USMLE Step 1 Questions With Correct Answers

What gland is found in the muscular triangle of the neck? - Answer Thyroid gland Is an afferent or efferent pupillary defect described as B/L pupillary constriction when light is shined in the unaffected eye and B/L paradoxical dilation when light is shined in the affected eye? - Answer Afferent pupillary defect (CN II lesion); in an efferent pupillary defect (CN III), B/L constrict when light is shined in the unaffected eye and consentual pupil constriction occurs when light is shined in the affected eye. What is the name of the spinal cord passing within the subarachnoid space and forming the spinal nerves that exit the lumbar and sacral foramina? - Answer Cauda equina Name the laryngeal muscle described by the following: • Pulls the arytenoids cartilages closer to the thyroid, relaxing the vocal ligaments and thereby decreasing the pitch - Answer Thyroarytenoid muscles Name the laryngeal muscle described by the following: • Tenses the vocal ligaments, increasing the distance between the cartilages, thereby increasing the pitch - Answer Cricothyroid muscles Name the laryngeal muscle described by the following: • Adducts the vocal ligaments, closes the air passageway during swallowing, and allows phonation - Answer Lateral cricoarytenoid muscles Name the laryngeal muscle described by the following: • Only muscle to abduct the vocal cords - Answer Posterior cricoarytenoid muscles Where does the parotid (Stensen's) duct enter the oral cavity? - Answer Opposite the second upper molar tooth From what aortic arch are the following structures derived? • Common and internal carotid arteries - Answer Third aortic arch MS CARD is my mnemonic for the aortic arch derivatives From what aortic arch are the following structures derived? • Degenerates - Answer Fifth MS CARD is my mnemonic for the aortic arch derivatives From what aortic arch are the following structures derived? • Stapes artery - Answer Second MS CARD is my mnemonic for the aortic arch derivatives From what aortic arch are the following structures derived? • Maxillary artery - Answer First MS CARD is my mnemonic for the aortic arch derivatives From what aortic arch are the following structures derived? • Arch of the aorta and right subclavian artery - Answer Fourth MS CARD is my mnemonic for the aortic arch derivatives From what aortic arch are the following structures derived? • Right and left pulmonary arteries and the ductus arteriosus - Answer Sixth MS CARD is my mnemonic for the aortic arch derivatives What abdominal muscle contributes to the anterior layer of the rectus sheath, forms the inguinal ligament, and in men gives rise to the external spermatic fascia of the spermatic cord? - Answer External abdominal oblique Name the compartment of the lower extremity and the nerve based on its movements. • Adduct the thigh and flex the hip - Answer Medial compartment of the thigh, obturator nerve Name the compartment of the lower extremity and the nerve based on its movements. • Plantar flex the foot, flex the toes, and invert the foot - Answer Posterior compartment of the leg, tibial nerve Name the compartment of the lower extremity and the nerve based on its movements. • Dorsiflex the foot, extend the toes, and invert the foot - Answer Anterior compartment of the leg, deep peroneal nerve Name the compartment of the lower extremity and the nerve based on its movements. • Flex the hip and extend the knee - Answer Anterior compartment of the thigh, femoral nerve Name the compartment of the lower extremity and the nerve based on its movements. • Extend the hip and flex the knee - Answer Posterior compartment of the thigh, tibial nerve Name the compartment of the lower extremity and the nerve based on its movements. • Plantar flex the foot and evert the foot - Answer Lateral compartment of the leg, superficial peroneal nerve What are the five branches of the posterior cord of the brachial plexus? - Answer STARS 1. Upper Subscapularis 2. Thoracodorsal 3. Axillary 4. Radial 5. Lower Subscapularis Name the correct artery. • The right recurrent laryngeal nerve passes around it. - Answer Right brachiocephalic artery Name the correct artery. • The left recurrent laryngeal nerve passes around it. - Answer Arch of the aorta The inferior mesenteric artery drains into it. - Answer The splenic vein Are the quadrate and caudate lobes of the liver functionally part of the left or right lobe? - Answer Functionally they are part of the left lobe of the liver because they receive their blood supply from the left hepatic artery. Anatomically they are considered part of the right lobe of the liver. What bones make up the acetabulum? - Answer Pubis, ilium, and ischium What is the anatomic positioning of the right and left gastric nerve plexus of the esophagus as they pass through the diaphragm? - Answer LARP: Left goes Anterior and Right goes Posterior (because of the rotation of the gut; remember your embryology!) What vessel is lacerated in an epidural hematoma? - Answer Middle meningeal artery True or false? Below the arcuate line, all the aponeurotic fibers run anterior to the rectus abdominis. - Answer TRUE What ocular muscle • Adducts the eyeball and is involved in horizontal conjugate gaze? - Answer Medial rectus (CN III) (LR6 SO4)3 What ocular muscle • Elevates and adducts the eyeball? - Answer Superior rectus (CN III) (LR6 SO4)3 What ocular muscle • Depresses and abducts the eyeball? - Answer Superior Oblique (CN IV) (LR6 SO4)3 What ocular muscle • Elevates and abducts the eyeball? - Answer Inferior Oblique (CN III) (LR6 SO4)3 What ocular muscle • Abducts the eyeball and is involved in horizontal conjugate gaze? - Answer Lateral rectus (CN VI) (LR6 SO4)3 What ocular muscle • Depresses and adducts the eyeball? - Answer Inferior rectus (CN III) (LR6 SO4)3 Which muscles of the eye are under parasympathetic control? - Answer Constrictor pupillae and ciliary muscles Which direction does the uvula deviate in a left vagus nerve lesion? - Answer A left CN X lesion results in the uvula deviating to the right. (Uvula points away from the affected side.) Is a subdural hematoma an arterial or venous bleed? - Answer Subdural hematoma is a rupture of the cerebral veins where they enter the superior sagittal sinus. Which CNs are found in the midline of the brainstem? - Answer CN I, II, III, VI, and XII Add 1 + 1 = 2, 1 + 2 = 3, 1 + 2 + 3 = 6, 1 + 2 + 3 + 6 = 12 What muscles insert in or on the intertubercular groove of the humerus? - Answer "Lady between two Majors": latissimus dorsi, pectoralis major, and teres major What nerve supplies taste sensation to the anterior two-thirds of the tongue? - Answer Chorda tympani of CN VII What part of the heart forms • The right border? - Answer Right atrium What part of the heart forms • Left border? - Answer Left ventricle and auricle of left atrium What part of the heart forms • Apex? - Answer Tip of the left ventricle What part of the heart forms • Base? - Answer Left atrium and tip of the right atrium What part of the heart forms • Superior border? - Answer Conus arteriosus of the right ventricle and right and left auricles What part of the heart forms • Anterior wall? - Answer Right ventricle What part of the heart forms • Posterior wall? - Answer Left atrium What part of the heart forms • Diaphragmatic wall? - Answer Left ventricle and tip of right ventricle What nerves carry the sensory and motor components of the blink reflex? - Answer CN V1 carries the sensory and CN VII carries the motor component of the blink reflex. What muscle keeps the stapes taut against the oval window? - Answer Stapedius muscle Name the components of the femoral canal, working laterally to medially. - Answer NAVEL: Femoral Nerve, Artery, Vein, Empty space, and Lymphatics/Lacunar ligament What muscle is most superior in the orbit? - Answer Levator palpebrae superioris What portion of the pericardium adheres to the tunica adventitia of the great vessels? - Answer Fibrous pericardium What two veins form the portal vein? - Answer The superior mesenteric vein and the splenic vein (after it receives the inferior mesenteric vein) join to form the portal vein. What CNs are responsible for the sensor and motor components of the light reflex? - Answer CN II is the sensory limb and CN III is the motor component through parasympathetic stimulation. Arrange the following layers in the correct sequence through which a needle must pass in a lumbar puncture. • Skin • Subarachnoid space • Interspinous ligament • Dura mater • Deep fascia • Epidural space • Superficial fascia • Interlaminar space • Supraspinous ligament • Arachnoid mater - Answer During a lumbar puncture the needle passes through the interlaminar space in the midline of L3-L4, with the tip of the iliac crest in the flexed position as the landmark. Order of puncture: 1. Skin 2. Superficial fascia 3. Deep fascia 4. Supraspinous ligament 5. Interspinous ligament 6. Interlaminar space 7. Epidural space 8. Dura mater 9. Arachnoid mater 10. Subarachnoid space. (They ask this in some variation every year, so know it.) What ocular ganglion is affected if the pupil on the affected side sluggishly responds to light with normal accommodation? - Answer Ciliary ganglion producing a tonic pupil What is the name for the most prominent spinous process? - Answer Vertebra prominens (C7 in 70% of cases, C6 in 20%, T1 in 10%) What muscles make up the rotator cuff? - Answer SITS—Subscapularis, Infraspinatus, Teres minor, Supraspinatus What is the function of white rami communicantes? - Answer They are preganglionic sympathetic axons. They are white because they are myelinated. What muscle or muscles are innervated by the following nerves? • Suprascapular nerve - Answer Supraspinatus and infraspinatus What muscle or muscles are innervated by the following nerves? • Upper subscapularis nerve - Answer Subscapularis What muscle or muscles are innervated by the following nerves? • Thoracodorsal nerve - Answer Latissimus dorsi What muscle or muscles are innervated by the following nerves? • Long thoracic nerve - Answer Serratus anterior What nerve is associated with the following functions? • Flex the wrist and digits, pronate the wrist and the LOAF (Lumbricales, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis) muscles of the hand - Answer Median nerve What nerve is associated with the following functions? • Flex the shoulder, flex the elbow, and supinate the elbow - Answer Musculocutaneous nerve What nerve is associated with the following functions? • Innervation of the flexor carpi ulnaris, flexor digiti profundus (pinky and ring fingers), and the intrinsic muscles of the hand - Answer Ulnar nerve What nerve is associated with the following functions? • Supinate the wrist, extend the wrist and digits, extend the shoulder and elbow - Answer Radial nerve What abdominal muscle runs horizontally, contributes to the posterior rectus sheath, and contributes to form the conjoint tendon? - Answer Transverse abdominis Which CNs act as the sensory and motor components of the gag reflex? - Answer The sensory limb is via CN IX, and the motor limb is from CN X. Which kidney is lower? Why? - Answer The right kidney is lower in the abdominal cavity because of the amount of space the liver occupies. What two regions of the vertebral column are considered primary curvatures? - Answer Thoracic and sacral What vein drains the lower third of the thoracic wall? - Answer Hemiazygous vein At what point does the axillary artery become the brachial artery? - Answer When it crosses the teres major What direction would the tongue protrude in a left CN XII lesion? - Answer Left CN XII lesion would result in the tongue pointing to the left (points at the affected side). At what vertebral level does the common carotid artery bifurcate? - Answer C4 (the upper border of the thyroid cartilage) True or false? Males are more likely to develop femoral hernias than females. - Answer False. Females are more likely to develop femoral hernias then males (remember Female's Femoral). In what compartment of the thigh is the profundus femoris artery found? - Answer Anterior compartment (it's the blood supply to the posterior compartment) Where is the cupola of the lung in relation to the subclavian artery and vein? - Answer The cupola of the lung is posterior to the subclavian artery and vein. It is the reason one must be cautious when performing subclavian venipuncture. True or false? The first cervical vertebra has no vertebral body. - Answer True. The odontoid process of C2 acts as the vertebral body of C1 allowing lateral rotation of the head. What is the largest muscle in the body? - Answer Gluteus maximus At what vertebral levels does the aortic arch begin and end? - Answer It both begins and ends at T4 (sternal angle [of Louis]). What artery travels with the following veins? • Great cardiac vein - Answer Left anterior descending artery What artery travels with the following veins? • Middle cardiac vein - Answer Posterior interventricular artery What artery travels with the following veins? • Small cardiac vein - Answer Right coronary artery The ophthalmic artery is a branch of what vessel? - Answer Internal carotid artery What structure or structures cross the diaphragm at • T8 level? - Answer IVC Remember: 1 at T8, 2 at T10, and 3 at T12 What structure or structures cross the diaphragm at • T10 level? - Answer Esophagus and esophageal nerve plexus (CN X) Remember: 1 at T8, 2 at T10, and 3 at T12 What structure or structures cross the diaphragm at • T12 level? - Answer Aorta, azygos vein, and thoracic duct Remember: 1 at T8, 2 at T10, and 3 at T12 Is the carotid sinus sensitive to pressure or oxygen? - Answer The carotid sinus is a pressure-sensitive (low) receptor, while the carotid body is an oxygen-sensitive (low) receptor. (Remember "Sinus Pressure"). What nerve or nerves supply general sensation and taste to the posterior third of the tongue? - Answer CN XI and X Which muscle of the eye is under sympathetic control? - Answer Dilator pupillae muscle True or false? both the left and right lungs have an oblique fissure? - Answer True. on the right lung the oblique fissure divides the middle from the inferior lobe and the horizontal fissure further divides the middle from the upper lobe. On the left the oblique divides the superior from the inferior lobe. What are the three branches of the lateral cord of the brachial plexus? - Answer 1. Lateral pectoral 2. Lateral head of the median 3. Musculocutaneus What is the major difference between the veins in the face and the veins in the rest of the body? - Answer There are no valves and no smooth muscle in the walls of the veins in the face. Name the bony articulations of the following sites. Be specific. • Shoulder - Answer Clavicle, acromion, and glenoid fossa of the scapula and the humerus Name the bony articulations of the following sites. Be specific. • Elbow - Answer Humerus with ulna (major) and radius (minor) Name the bony articulations of the following sites. Be specific. • Wrist - Answer Radius with scaphoid and lunate and ulna with triquetrum and pisiform (Remember, for major articulations, wrist/radius and humerus/ulna = elbow) What is the only laryngeal muscle innervated by the external laryngeal nerve? - Answer Cricothyroid muscle; all other laryngeal muscles are innervated by the recurrent laryngeal nerve. What seven structures are found in more than one mediastinum? - Answer Esophagus, SVC, vagus nerve, azygos vein, thoracic duct, thymus, and phrenic nerve How many bronchopulmonary segments are on the right lung? Left lung? - Answer There are 10 bronchopulmonary segments on the right and 8 on the left. The duodenal-jejunal flexure is suspended from the posterior abdominal wall by what? - Answer Ligament of Treitz What is the only tongue muscle innervated by CN X? - Answer Palatoglossus muscle is innervated by CN X; all other tongue muscles are innervated by CN XII. What abdominal muscle runs in a posteroinferior direction, splits to contribute to the rectus sheath, contributes to the formation of the conjoint tendon, and in men gives rise to the middle spermatic fascia and the cremasteric muscle of the spermatic cord? - Answer Internal abdominal oblique What are the five branches of the superior mesenteric artery? - Answer Inferior pancreaticoduodenal, middle colic, right colic, ileocolic, and 10 to 15 intestinal arteries What spinal nerves contribute to the pelvic splanchnic (parasympathetic) nerves that innervate the detrusor muscle of the urinary bladder? - Answer S2, S3, S4—keeps the pee-pee off the floor! What connects the third and the fourth ventricles? - Answer Cerebral aqueduct What nerve and artery could be affected in a humeral neck fracture? - Answer Axillary nerve and posterior humeral artery What type of hernia is described as passing through the deep lateral ring of the inguinal canal? - Answer Indirect hernia passes in the inguinal canal; a direct hernia passes directly through Hesselbach's triangle. What two vessels come together to form the external jugular vein? - Answer 1. Posterior auricular vein 2. Posterior division of the retromandibular vein What is the only vein in the body with a high O2 content? - Answer The pulmonary vein, which carries oxygenated blood from the lung to the left atrium. What are the three branches of the celiac trunk? - Answer The left gastric, splenic, and common hepatic arteries What region of the pharynx does the eustachian tube enter? - Answer Nasopharynx What is the only muscle of the soft palate that is innervated by CN V3? - Answer The tensor veli palatine is innervated by the mandibular division of the trigeminal nerve; all others are innervated by CN X. How many pairs of spinal nerves exit from the spinal cord? - Answer 31 pairs What artery turns into the dorsalis pedis when it crosses the extensor retinaculum? - Answer Anterior tibial artery What is the term for pupils that react normally to accommodation but have bilateral loss of constriction in response to light? - Answer Argyll Robertson pupils What connects the lateral ventricles to the third ventricle? - Answer Foramen of Monro What nerve supplies general sensation to the anterior two-thirds of the tongue? - Answer Lingual nerve of CN V3 What type of pleura is adherent to the surface of the organ? - Answer Visceral pleura What artery supplies the left ventricle, left atrium, and interventricular septum? - Answer Left coronary artery Where are the tonsillar tissues? - Answer Waldeyer's ring What is the name of the superficial subcutaneous fascia of the abdomen containing fat? - Answer Camper's fascia; Scarpa's fascia is devoid of fat. (Remember campers are fat.) What are the three anatomic characteristics that differentiate the large bowel from the small bowel and the rectum? - Answer 1. Tinea coli 2. Haustra 3. Epiploic appendages What area of the posterior aspect of the eye has no photoreceptors? - Answer The optic disk is the blind spot. At the level of rib 6, the internal thoracic artery divides into what two arteries? - Answer Musculophrenic and superior epigastric arteries What is the name of inflammation of the prepatellar bursa? - Answer Housemaid's knee What nerve roots constitute the cervical plexus? - Answer C1 through C4 Name the compartment of the mediastinum associated with the following thoracic structures: • Heart and pericardium - Answer Middle Name the compartment of the mediastinum associated with the following thoracic structures: • Descending aorta - Answer Posterior Name the compartment of the mediastinum associated with the following thoracic structures: • Thymus - Answer Superior and anterior Name the compartment of the mediastinum associated with the following thoracic structures: • Phrenic nerve - Answer Superior and middle Name the compartment of the mediastinum associated with the following thoracic structures: • Esophagus - Answer Superior and posterior Name the compartment of the mediastinum associated with the following thoracic structures: • Trachea - Answer Superior Name the compartment of the mediastinum associated with the following thoracic structures: • Ascending aorta - Answer Middle Name the compartment of the mediastinum associated with the following thoracic structures: • Thoracic duct - Answer Superior and posterior Name the compartment of the mediastinum associated with the following thoracic structures: • Azygos vein - Answer Superior and posterior Name the compartment of the mediastinum associated with the following thoracic structures: • SVC - Answer Superior and middle Name the compartment of the mediastinum associated with the following thoracic structures: • Splanchnic nerves - Answer Posterior Name the compartment of the mediastinum associated with the following thoracic structures: • Aortic arch - Answer Superior Name the compartment of the mediastinum associated with the following thoracic structures: • IVC - Answer Middle Name the compartment of the mediastinum associated with the following thoracic structures: • Vagus nerve - Answer Posterior Name the compartment of the mediastinum associated with the following thoracic structures: • Brachiocephalic vein - Answer Superior Name the compartment of the mediastinum associated with the following thoracic structures: • Pulmonary artery and veins - Answer Middle Name the compartment of the mediastinum associated with the following thoracic structures: • Left common carotid artery - Answer Superior Name the compartment of the mediastinum associated with the following thoracic structures: • Left subclavian artery - Answer Superior What is the only organ in the body supplied by preganglionic sympathetic fibers? - Answer Adrenal medulla The left subclavian artery is a branch of what artery? - Answer The left is a branch of the aortic arch, while the right is a branch of the brachiocephalic trunk. What are the four muscles of mastication? - Answer 1. Masseter 2. Temporalis 3. Medial pterygoid 4. Lateral pterygoid With what thoracic vertebra or vertebrae does rib 7 articulate? - Answer Rib 7 articulates with T7 and T8. Each rib articulates with the corresponding numerical vertebral body and the vertebral body below it. What are the three branches of the inferior mesenteric artery? - Answer Left colic, superior rectal, and sigmoidal arteries What is the only valve in the heart with two cusps? - Answer Mitral (bicuspid) valve What are five clinical signs of portal HTN? - Answer Caput medusa, internal hemorrhoids, esophageal varices, retroperitoneal varices, and splenomegaly What three muscles constitute the erector spinae? - Answer 1. Iliocostalis 2. Longissimus 3. Spinalis ("I Love Science" muscles) What nerve is compromised in carpal tunnel syndrome? - Answer Median nerve What vascular injury may result from a supracondylar fracture of the femur? - Answer The popliteal artery, the deepest structure in the popliteal fossa, risks injury in a supracondylar fracture of the femur. What nerve and artery could be affected in a midshaft humeral fracture? - Answer Radial nerve and the profunda brachii artery Name the 10 retroperitoneal organs. - Answer . Duodenum (all but the first part) 2. Ascending Colon 3. Ureters 4. Pancreas 5. Supra renal glands (adrenals) 6. Descending colon 7. Aorta 8. Kidneys 9. Rectum 10. IVC D CUPS DAKRI is the mnemonic, everything else is covered with peritoneum Ventral rami of what cervical nerves constitute the phrenic nerve? - Answer C3, C4, and C5 keep the diaphragm alive! What is the region of the fallopian tube where fertilization most commonly occurs? - Answer Ampulla What foramen must be traversed for entry into the lesser peritoneal sac? - Answer Foramen of Winslow Name the structure that enters or exits the following foramina: • Foramen magnum - Answer CN XI, vertebral arteries Name the structure that enters or exits the following foramina: • Foramen spinosum - Answer Middle meningeal artery Name the structure that enters or exits the following foramina: • Foramen rotundum - Answer CN V2 Name the structure that enters or exits the following foramina: • Foramen ovale - Answer CN V3 and the lesser petrosal nerve Name the structure that enters or exits the following foramina: • Jugular foramen - Answer CN IX, X, and XI; sigmoid sinus Name the structure that enters or exits the following foramina: • Carotid canal - Answer Internal carotid artery and sympathetic plexus Name the structure that enters or exits the following foramina: • Stylomastoid foramen - Answer CN VII Name the structure that enters or exits the following foramina: • Hypoglossal canal - Answer CN XII Name the structure that enters or exits the following foramina: • Internal auditory meatus - Answer CN VII and VIII Name the structure that enters or exits the following foramina: • Optic canal - Answer CN II and ophthalmic artery Name the structure that enters or exits the following foramina: • Cribriform plate - Answer CN I What vessel can be found atop the scalene anterior? - Answer Subclavian vein What component of the corneal reflex is lost in a CN VII deficit? - Answer Motor aspect A motor lesion to the right CN V results in deviation of the jaw to which side? - Answer A right CN V lesion results in weakened muscles of mastication, and the jaw deviates to the right. What two arteries join to form the superficial and deep palmar arches of the hand? - Answer Ulnar and radial arteries (ulnar is the main supplier) What two ligaments of the uterus are remnants of the gubernaculum? - Answer Round and ovarian ligaments What segments of the lumbosacral plexus form the following nerves? • Tibial nerve - Answer L4 to S3 (L2 to L4, thigh; L4 to S3, leg) What segments of the lumbosacral plexus form the following nerves? • Common peroneal nerve - Answer L4 to S3 (L2 to L4, thigh; L4 to S3, leg) What segments of the lumbosacral plexus form the following nerves? • Femoral nerve - Answer L2 to L4 (L2 to L4, thigh; L4 to S3, leg) What segments of the lumbosacral plexus form the following nerves? • Obturator nerve - Answer L2 to L4 (L2 to L4, thigh; L4 to S3, leg) What three structures are in contact with the left colic flexure? With the right colic flexure? - Answer Left: stomach, spleen, and left kidney; right: liver, duodenum, and right kidney What three muscles constitute the pes anserinus? - Answer 1. Sartorius 2. Gracilis 3. Semitendinous What is the only pharyngeal muscle not innervated by CN X? - Answer Stylopharyngeus muscle is innervated by CN IX; all other pharyngeal muscles are innervated by CN X. What vessels carry deoxygenated blood into the lungs from the right ventricle? - Answer The right and left pulmonary arteries, the only arteries that carry deoxygenated blood Fracture of the fibular neck, resulting in foot drop, is an injury of what nerve? - Answer Common peroneal nerve What vein is formed by the union of the right and left brachiocephalic veins? - Answer Superior vena cava If inserting a needle to perform a pleural tap or insertion of a chest tube, do you use the inferior or the superior border of a rib as your landmark? Why? - Answer The superior border of the inferior intercostal rib is your landmark for a pleural tap because along the inferior border of each rib is the neurovascular bundle, and you would risk injury if you went below the rib. What muscle laterally rotates the femur to unlock the knee? - Answer Popliteus What chamber of the eye lies between the iris and the lens? - Answer Posterior chamber What artery supplies the right atrium, right ventricle, sinoatrial and atrioventricular nodes? - Answer Right coronary artery What four branches of the brachial plexus arise prior to the first rib? - Answer 1. Dorsal scapular 2. Suprascapular 3. Long thoracic 4. Nerve to subclavius What vertebral level is marked by the xiphoid process? - Answer T9 What lower extremity nerve is described by the following motor loss? • Loss of eversion; inversion, dorsiflexion, and plantarflexion of the foot - Answer Common peroneal nerve What lower extremity nerve is described by the following motor loss? • Loss of flexion of the knees and toes, plantarflexion, and weakened inversion - Answer Tibial nerve What lower extremity nerve is described by the following motor loss? • Loss of knee extension, weakened hip flexion - Answer Femoral nerve What lower extremity nerve is described by the following motor loss? • Loss of abduction of the hip resulting in Trendelenburg gait - Answer Superior gluteal nerve What lower extremity nerve is described by the following motor loss? • Loss of flexion of the knee and all function below the knee, weakened extension of the thigh - Answer Sciatic nerve What lower extremity nerve is described by the following motor loss? • Loss of adduction of the thigh - Answer Obturator nerve What nerve lesion presents with ape or simian hand as its sign? - Answer Median nerve lesion What muscle acts in all ranges of motion of the arm? - Answer Deltoid What is the first branch of the abdominal artery? - Answer Inferior phrenic artery What vessel does the right gonadal vein drain into? - Answer The right gonadal vein drains into the inferior vena cava directly, and the left gonadal vein drains into the left renal vein. What two muscles do you test to see whether CN XI is intact? - Answer Trapezius and sternocleidomastoid What two CNs are responsible for the carotid body and sinus reflexes? - Answer CN IX and X At what vertebral level does the trachea bifurcate? - Answer T4 vertebral level posteriorly and anteriorly at the sternal angle (angle of Louis). What is the function of the arachnoid granulations? - Answer Resorb CSF into the blood Damage to what nerve will give you winged scapula? - Answer Long thoracic nerve. To avoid confusing long thoracic nerve and lateral thoracic artery: long has an n for nerve; lateral has an a for artery. What portion of the intervertebral disk is a remnant of the notochord? - Answer Nucleus pulposus What component of the pelvic diaphragm forms the rectal sling (muscle of continence)? - Answer Puborectalis What are the five branches of the median cord of the brachial plexus? - Answer Four Ms and a U 1. Median 2. Medial antebrachial 3. Medial pectoral 4. Medial brachial cutaneus 5. Ulnar What bone houses the ulnar groove? - Answer Humerus (between the medial epicondyle and the trochlea) What CN is associated with the sensory innervation of • Nasopharynx? - Answer Maxillary division of CN V and glossopharyngeal nerves What CN is associated with the sensory innervation of • Oropharynx? - Answer Glossopharyngeal nerve What CN is associated with the sensory innervation of • Laryngopharynx? - Answer Vagus nerve What protective covering adheres to the spinal cord and CNS tissue? - Answer Pia mater What is the name of the urinary bladder where the ureters enter and the urethra exits? - Answer Urinary trigone What is the term when the brachial artery is compressed, resulting in ischemic contracture of the hand? - Answer Volkmann's contracture What attaches the cusps of the valves to the papillary muscles in the heart? - Answer Chordae tendineae What is the lymphatic drainage of the pelvic organs? - Answer Internal iliac nodes What bursa is inflamed in clergyman's knee? - Answer Infrapatellar bursa What muscle is the chief flexor of the hip? - Answer Psoas major What component of the ANS, when stimulated, results in bronchoconstriction? - Answer Parasympathetic stimulation, via the vagus nerve, results in bronchoconstriction, whereas sympathetic stimulation results in bronchodilation. What muscles in the hand adduct the fingers? - Answer The Palmar interosseus ADducts, whereas the Dorsal interosseus ABducts (PAD and DAB) What type of cerebral bleed is due to a rupture of a berry aneurysm in the circle of Willis? - Answer Subarachnoid hematoma What are the five terminal branches of the facial nerve? - Answer 1. Temporal 2. Zygomatic 3. Buccal 4. Mandibular 5. Cervical (Two Zebras Bit My Clavicle.) What structure of the knee is described thus? • C-shaped shock absorber; aids in attachment of the tibia to the femur via the medial collateral ligament - Answer Medial meniscus What structure of the knee is described thus? • Prevents posterior displacement and has medial-to-lateral attachment on the tibia - Answer Posterior cruciate ligament What structure of the knee is described thus? • Prevents adduction - Answer Lateral collateral ligament What structure of the knee is described thus? • Prevents anterior displacement and has lateral-to-medial attachment on the tibia - Answer ACL What structure of the knee is described thus? • Prevents abduction - Answer Medial collateral ligament What branches of CN X are the sensory and motor components of the cough reflex? Be specific. - Answer The sensory component is through the superior laryngeal nerve, and the motor limb is via the recurrent laryngeal nerve. What nerves provide sensory innervation above the vocal cords? Below the vocal cords? - Answer The internal laryngeal nerve supplies sensory information from above the vocal cords while the recurrent laryngeal nerve supplies sensory information below. From what pharyngeal groove is the external auditory meatus derived? - Answer First pharyngeal groove; all others degenerate. What embryonic structure forms the adult male structure? • Corpus cavernosus, corpus spongiosum, and glans and body of the penis - Answer Phallus What embryonic structure forms the adult male structure? • Scrotum - Answer Labioscrotal swelling What embryonic structure forms the adult male structure? • Urinary bladder, urethra, prostate gland, bulbourethral gland - Answer Urogenital sinus What embryonic structure forms the adult male structure? • Testes, seminiferous tubules, and rete testes - Answer Gonads What embryonic structure forms the adult male structure? • Ventral part of the penis - Answer Urogenital folds What embryonic structure forms the adult male structure? • Gubernaculum testes - Answer Gubernaculum What embryonic structure forms the adult male structure? • Epididymis, ductus deferens, seminal vesicle, and ejaculatory duct - Answer Mesonephric duct Which PG is associated with maintaining a PDA? - Answer PGE and intrauterine or neonatal asphyxia maintain patency of the ductus arteriosus. Indomethacin, ACh, and catecholamines promote closure of the ductus arteriosus. When does the primitive gut herniate out of the embryo? When does it go back into the embryo? - Answer 6 weeks 10 weeks What results when the palatine prominences fail to fuse with the other side? - Answer Cleft palate What is the term for a direct connection between the intestine and the external environment through the umbilicus because the vitelline duct persists? - Answer Vitelline fistula Where do the primordial germ cells arise? - Answer From the wall of the yolk sac What disorder is due to a 5--reductase deficiency, resulting in testicular tissue and stunted male external genitalia? - Answer Male pseudo-intersexuality (hermaphrodite); these individuals are 46XY. Does the zygote divide mitotically or meiotically? - Answer The zygote divides mitotically; only germ cells divide meiotically. During what embryonic week does the intraembryonic coelom form? - Answer Third week Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Cerebral hemispheres - Answer Proencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Midbrain - Answer Mesencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Cerebellum - Answer Rhombencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Medulla - Answer Rhombencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Diencephalon - Answer Proencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Metencephalon - Answer Rhombencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Telencephalon - Answer Proencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Thalamus - Answer Proencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Eye - Answer Proencephalon* *diencephalon derivative Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Pons - Answer Rhombencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Myelencephalon - Answer Rhombencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Pineal gland - Answer Proencephalon* *diencephalon derivative Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Cerebral aqueduct - Answer Mesencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Neurohypophysis - Answer Proencephalon* *diencephalon derivative Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Third ventricle - Answer Proencephalon Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Hypothalamus - Answer Proencephalon* *diencephalon derivative Name the primary vesicle the following structures are derived from (proencephalon, mesencephalon, or rhombencephalon). • Lateral ventricles - Answer Proencephalon What malignant tumor of the trophoblast causes high levels of hCG and may occur after a hydatidiform mole, abortion, or normal pregnancy? - Answer Gestational trophoblastic neoplasia (GTN or choriocarcinoma) What syndrome is due to a deficiency of surfactant? - Answer Respiratory distress syndrome; treatment with cortisol and thyroxine can increase production of surfactant. How many oogonia are present at birth? - Answer None; they are not formed until a girl reaches puberty. What right-to-left shunt occurs when the aorta opens into the right ventricle and the pulmonary trunk opens into the left ventricle? - Answer Transposition of the great vessels arises from a failure of the aorticopulmonary septum to grow in a spiral. What are the adult remnants of the following structures? • Left umbilical vein - Answer Ligament teres What are the adult remnants of the following structures? • Foramen ovale - Answer Fossa ovale What are the adult remnants of the following structures? • Right and left umbilical arteries - Answer Medial umbilical ligaments What are the adult remnants of the following structures? • Ductus arteriosus - Answer Ligamentum arteriosum What are the adult remnants of the following structures? • Ductus venosus - Answer Ligamentum venosum Mandibular hypoplasia, down-slanted palpebral fissures, colobomas, malformed ears, and zygomatic hypoplasia are commonly seen in what pharyngeal arch 1 abnormality? - Answer Treacher Collins syndrome What is the tetrad of tetralogy of Fallot? - Answer SHIP: Shifting of the aorta, Hypertrophy of the right ventricle, Interventricular septal defect, Pulmonary stenosis What is the term for the external urethra opening onto the ventral surface of the penis? - Answer Hypospadia What CN is associated with the • First pharyngeal arch? - Answer CN V What CN is associated with the • Second pharyngeal arch? - Answer CN VII What CN is associated with the • Third pharyngeal arch? - Answer CN IX What CN is associated with the • Fourth pharyngeal arch? - Answer CN X What CN is associated with the • Fifth pharyngeal arch? - Answer None; it degenerates. What CN is associated with the • Sixth pharyngeal arch? - Answer CN X What disease results in a failure of neural crest cells to migrate to the myenteric plexus of the sigmoid colon and rectum? - Answer Hirschsprung's disease (colonic gangliosus) What immunologic syndrome is due to a pharyngeal pouch 3 and 4 failure? - Answer DiGeorge's syndrome What embryonic structure, around day 19, tells the ectoderm above it to differentiate into neural tissue? - Answer The notochord What is the term for failure of the testes to descend into the scrotum? - Answer Cryptorchidism; normally the testes descend into the scrotum within 3 months of birth. Is a membranous septal defect more commonly interventricular or interatrial? - Answer Membranous septal defects are interventricular; a persistent patent ovale results in an interatrial septal defect. What pharyngeal pouch and groove persist when a pharyngeal fistula is formed? - Answer The second pharyngeal pouch and groove How early can a pregnancy be detected by hCG assays in the blood? In urine? - Answer hCG can be detected in the blood by day 8 and in the urine by day 10. From what pharyngeal pouch is the following structure derived? • Middle ear - Answer First M PITS for pharyngeal pouch derivatives From what pharyngeal pouch is the following structure derived? • Superior parathyroid gland and ultimobranchial body of the thyroid - Answer Fourth M PITS for pharyngeal pouch derivatives From what pharyngeal pouch is the following structure derived? • Inferior parathyroid gland and thymus - Answer Third M PITS for pharyngeal pouch derivatives From what pharyngeal pouch is the following structure derived? • Palatine tonsil - Answer Second M PITS for pharyngeal pouch derivatives What is the term for the external urethra opening onto the dorsal surface of the penis? - Answer Epispadia True or false? In females, meiosis II is incomplete unless fertilization takes place. - Answer True. The elimination of the unfertilized egg is menses. What adult structures are derived from preotic somites? - Answer Muscles of the internal eye What disorder is associated with jaundice, white stools, and dark urine due to biliary duct occlusion secondary to incomplete recanalization? - Answer Extrahepatic biliary atresia What hormone, produced by the syncytiotrophoblast, stimulates the production of progesterone by the corpus luteum? - Answer hCG How many mature sperm are produced by one type B spermatogonium? - Answer Four All primary oocytes in females are formed by what age? - Answer They are all formed by the fifth month of fetal life. From what embryonic structure are the following structures derived? • The ascending aorta and the pulmonary trunk - Answer Truncus arteriosus From what embryonic structure are the following structures derived? • The sinus venarum, coronary sinus, and the oblique vein of the left atrium - Answer Sinus venosus From what embryonic structure are the following structures derived? • The right and left ventricles - Answer Primitive ventricle From what embryonic structure are the following structures derived? • The aortic vestibule and the conus arteriosus - Answer Bulbus cordis From what embryonic structure are the following structures derived? • The right and left atria - Answer Primitive atrium After a longstanding left-to-right shunt reverses, causing cyanosis, and becomes a right-to-left shunt, what is it termed? - Answer Eisenmenger's syndrome True or false? The thyroid gland is an embryologic foregut derivative. - Answer True. The thyroid gland, the lungs, and the pharyngeal pouches are foregut derivatives that are not a component of the gastrointestinal system. What embryonic structure forms the following adult structures? • Collecting ducts, calyces, renal pelvis, and ureter - Answer Mesonephric duct (ureteric bud) What embryonic structure forms the following adult structures? • Urinary bladder and urethra - Answer Urogenital sinus What embryonic structure forms the following adult structures? • External genitalia - Answer Phallus, urogenital folds, and labioscrotal swellings What embryonic structure forms the following adult structures? • Nephrons, kidney - Answer Metanephros What embryonic structure forms the following adult structures? • Median umbilical ligament - Answer Urachus True or false? The epithelial lining of the urinary bladder and the urethra are embryologic hindgut derivatives. - Answer TRUE Name the four ventral mesentery derivatives. - Answer 1. The lesser omentum (consisting of the hepatoduodenal and hepatogastric ligaments) 2. Falciform ligament 3. Coronary ligament of the liver 4. Triangular ligament of the liver Liver is ventral; all other ligaments are dorsal mesentery derivatives. Projectile nonbilious vomiting and a small knot at the right costal margin (olive sign) are hallmarks of what embryonic disorder? - Answer Hypertrophic pyloric stenosis due to hypertrophy of the muscularis externa, resulting in a narrowed pyloric outlet The separation of 46 homologous chromosomes without splitting of the centromeres occurs during what phase of meiosis? - Answer Meiosis I; disjunction with centromere splitting occurs during meiosis II. Blood and its vessels form during what embryonic week? - Answer Third week; they are derived from the wall of the yolk sac. What embryonic structure forms the adult female structures? • Glans clitoris, corpus cavernosus, and spongiosum - Answer Phallus What embryonic structure forms the adult female structures? • Gartner's duct - Answer Mesonephric duct What embryonic structure forms the adult female structures? • Ovary, follicles, rete ovarii - Answer Gonads What embryonic structure forms the adult female structures? • Uterine tube, uterus, cervix, and upper third of the vagina - Answer Paramesonephric ducts What embryonic structure forms the adult female structures? • Labia majora - Answer Labioscrotal swelling What embryonic structure forms the adult female structures? • Labia minora - Answer Urogenital folds What embryonic structure forms the adult female structures? • Ovarian and round ligaments - Answer Gubernaculum What embryonic structure forms the adult female structures? • Urinary bladder, urethra, greater vestibular glands, vagina - Answer Urogenital sinus What direction does the primitive gut rotate? What is its axis of rotation? - Answer The gut rotates clockwise around the superior mesenteric artery. What syndrome occurs when a 46XY fetus develops testes and female external genitalia? - Answer Testicular feminization syndrome (Dude looks like a lady!) Preeclampsia in the first trimester, hCG levels above 100, 00 mIU/mL, and an enlarged bleeding uterus are clinical signs of what? - Answer Hydatidiform mole True or false? The foramen ovale closes just prior to birth. - Answer False. It closes just after birth because the change in pulmonary circulation causes increased left atrial pressure. At ovulation, in what stage of meiosis II is the secondary oocyte arrested? - Answer Metaphase II What is the name for failed recanalization of the duodenum resulting in polyhydramnios, bile-containing vomitus, and a distended stomach? - Answer Duodenal atresia What remains patent in a hydrocele of the testis, allowing peritoneal fluid to form into a cyst? - Answer A patent processus vaginalis True or false? The respiratory system is derived from the ventral wall of the foregut. - Answer True. The laryngotracheal (respiratory) diverticulum is divided from the foregut by the tracheoesophageal septum. -------------------------------------------------------------------------------- What is the name for failure of the allantois to close, resulting in a urachal fistula or sinus? - Answer Patent urachus What structure is derived from the prochordal plate? - Answer The mouth What is the only organ supplied by the foregut artery that is of mesodermal origin? - Answer Spleen What tumor is derived from primitive streak remnants and often contains bone, hair, or other tissue types? - Answer Sacrococcygeal teratoma What two pathologic conditions occur when the gut does not return to the embryo? - Answer Omphalocele and gastroschisis True or false? For implantation to occur the zona pellucida must degenerate. - Answer True. Remember, it degenerates 4 to 5 days post fertilization, and implantation occurs 7 days post fertilization! What results when the maxillary prominence fails to fuse with the medial nasal prominence? - Answer Cleft lip What is the direction of growth for the primitive streak, caudal to rostral or rostral to caudal? - Answer The primitive streak grows caudal to rostral. During what embryonic week do somites begin to form? - Answer Third week In men, at what embryonic week do the primordial germ cells migrate to the indifferent gonad? - Answer Week four, and they remain dormant there until puberty. What embryonic week sees the formation of the notochord and the neural tube? - Answer Third week What right-to-left shunt occurs when only one vessel receives blood from both the right and left ventricles? - Answer Persistent truncus arteriosus What three embryonic cell layers form the chorion? - Answer 1. Cytotrophoblast 2. Syncytiotrophoblast 3. Extraembryonic mesoderm Where are the preganglionic neuron cell bodies, the CNS or the PNS? - Answer They are in the grey matter of the CNS. Which three CNs send sensory information to the solitary nucleus? - Answer CN VII, IX, and X; taste and general sensation for the tongue is sent to the solitary nucleus. What syndrome is associated with the following brainstem lesions? • Vertebral artery or anterior spinal artery occlusion, resulting in contralateral corticospinal tract and medial lemniscus tract deficits and an ipsilateral CN XII lesion - Answer Medial medullary syndrome What syndrome is associated with the following brainstem lesions? • Contralateral corticospinal and medial lemniscus tract deficits and an ipsilatera medial strabismus secondary to a lesion in CN VI - Answer Medial pontine syndrome What syndrome is associated with the following brainstem lesions? • Slow-growing acoustic neuroma producing CN VII deficiencies - Answer Pontocerebellar angle syndrome What syndrome is associated with the following brainstem lesions? • Occlusion of the PICA, resulting in ipsilateral limb ataxia, ipsilateral facial pain and temperature loss, contralateral pain and body temperature loss, ipsilateral Horner's syndrome, and ipsilateral paralysis of the vocal cords, palate droop, dysphagia, nystagmus, vomiting, and vertigo - Answer Lateral medullary (Wallenberg's) syndrome What syndrome is associated with the following brainstem lesions? • AICA or superior cerebellar artery occlusion, resulting in ipsilateral limb ataxia, ipsilateral facial pain and temperature loss, contralateral loss of pain and temperature to the body, ipsilateral Horner's syndrome, ipsilateral facial paralysis, and hearing loss - Answer Lateral pontine syndrome What syndrome is associated with the following brainstem lesions? • Posterior cerebral artery occlusion resulting in a contralateral corticospinal tract signs, contralateral corticobulbar signs to the lower face, and ipsilateral CN III palsy - Answer Medial midbrain (Weber's) syndrome What CNs are affected if there is a lesion in • The midbrain? - Answer CN III and IV What CNs are affected if there is a lesion in • The upper medulla? - Answer CN IX, X, and XII What CNs are affected if there is a lesion in • Pontomedullary junction? - Answer CN VI, VII, and VIII What CNs are affected if there is a lesion in • The upper pons? - Answer CN V What is the only CN nucleus found in the cervical spinal cord? - Answer Accessory nucleus What component of the trigeminal nuclei • Supplies the muscles of mastication? - Answer Motor nucleus of CN V What component of the trigeminal nuclei • Receives sensory input (all but pain and temperature) from the face, scalp, dura, and the oral and nasal cavities? - Answer Spinal trigeminal nucleus What component of the trigeminal nuclei • Forms the sensory component of the jaw jerk reflex? - Answer Mesencephalic nucleus What deep cerebellar nuclei receive Purkinje cell projections in • The flocculonodular lobe? - Answer The lateral vestibular nucleus What deep cerebellar nuclei receive Purkinje cell projections in • The vermis? - Answer The fastigial nucleus What deep cerebellar nuclei receive Purkinje cell projections in • The lateral cerebellar hemispheres? - Answer The interposed nucleus What deep cerebellar nuclei receive Purkinje cell projections in • The intermediate hemispheres? - Answer The dentate nucleus What is the only excitatory neuron in the cerebellar cortex, and what is its neurotransmitter? - Answer The granule cell is the only excitatory neuron in the cerebellar cortex, and it uses glutamate as its neurotransmitter. All the other cells in the cerebellum are inhibitory neurons, and they use GABA as their neurotransmitter. What three CNs are associated with conjugate eye movements? - Answer CN III, IV, and VI What is the term to describe the soft, flabby feel and diminished reflexes seen in patients with acute cerebellar injury to the deep cerebellar nuclei? - Answer Hypotonia (rag doll appearance) What bedside test is used to differentiate a dorsal column lesion from a lesion in the vermis of the cerebral cortex? - Answer The Romberg sign is present if the patient sways or loses balance when standing with eyes open. In a dorsal column lesion, patients sway with eyes closed. (Don't forget this one.) Which one of the cerebellar peduncles is mainly responsible for outgoing (efferent) information? - Answer Superior cerebellar peduncle; the inferior and the middle consist mainly of incoming (afferent) tracts and fibers. What tract carries unconscious proprioceptive information from the Golgi tendon organs and muscle spindles to the cerebellum, helping monitor and modulate muscle movements? - Answer Lower extremity and lower trunk information travels in the dorsal spinocerebellar tract. The upper trunk and extremity information travels in the cuneocerebellar tract. (Cuneocerebellar and fasciculus cuneatus both apply to upper extremities.) What reflex, seen in lesions of the corticospinal tract, is an extension of the great toe with fanning the of remaining toes? - Answer The Babinski reflex is present in UMN lesions. Muscle atrophy due to disuse, hyperreflexia, spastic paralysis, increased muscle tone, and weakness are commonly seen in UMN lesions. What is the triad of Horner's syndrome? - Answer Ptosis (eyelid drooping), miosis (pupillary constriction), and anhydrosis (lack of sweating) occur when the preganglionic sympathetic fibers from T1-to T4 are obstructed. What component of the inner ear • Contains perilymph and responds to angular acceleration and deceleration of the head? - Answer Semicircular canal What component of the inner ear • Contains endolymph and responds to head turning and movement? - Answer Semicircular duct What component of the inner ear • Contains endolymph and gravity receptors monitoring linear acceleration and deceleration of the head, noting changes in head position? - Answer Utricle and saccule What is the name of demyelination of the corticospinal tract and the dorsal column in the spinal cord due most commonly to a vitamin B12 deficiency? - Answer Subacute combined degeneration, which is bilateral below the level of the lesion. What encephalopathy causes ocular palsies, confusion, and gait abnormalities related to a lesion in the mammillary bodies and/or the dorsomedial nuclei of the thalamus? - Answer Wernicke's encephalopathy Which thalamic nucleus receives auditory input from the inferior colliculus? - Answer MGB Where are the postganglionic neuron cell bodies, the CNS or the PNS? - Answer They are in ganglia in the PNS. What disease is a cavitation of the spinal cord causing bilateral loss of pain and temperature at the level of the lesion? - Answer Syringomyelia What nucleus of the hypothalamus receives visual input from the retina and helps set the circadian rhythm? - Answer Suprachiasmatic nucleus Are white rami preganglionic or postganglionic fibers? - Answer White rami are preganglionic fibers, whereas grey rami are postganglionic fibers. What area of the hypothalamus is responsible for recognizing a decrease in body temperature and mediates the response to conserve heat? - Answer Posterior hypothalamic zones; lesions here result in poikilothermy (environmental control of one's body temperature). What CN transmits sensory information from the cornea? - Answer CN V1, the occulomotor division of the trigeminal nerve, is the sensory component of the corneal reflex. What preganglionic sympathetic fibers are responsible for innervating the smooth muscle and glands of the pelvis and the hindgut? - Answer Lumbar splanchnics Where are the cell bodies for the DCML and spinothalamic sensory systems? - Answer The first sensory neuron is in the dorsal root ganglia. It carries ascending sensory information in the dorsal root of a spinal nerve, eventually synapsing with second sensory neuron. In the brainstem (DCML) and the spinal cord (spinothalamic) the second neuron cell body sends its axons to synapse in the thalamus. The third sensory neuron cell body is a thalamic nuclei that sends its fibers to the primary somatosensory cortex. What term describes the reflex that increases the curvature of the lens, allowing near vision? - Answer Accommodation What CN carries preganglionic parasympathetic fibers that innervate the viscera of the neck, thorax, foregut, and midgut? - Answer CN X (Remember, the vagus nerve supplies the parasympathetic information from the tip of the pharynx to the end of the midgut and all between.) What area of the hypothalamus is responsible for recognizing an increase in body temperature and mediates the response to dissipate heat? - Answer Anterior hypothalamic zone; lesions here result in hyperthermia. What excitatory fibers arise from the inferior olivary nuclei on the contralateral side of the body? - Answer Climbing fibers;, they are monosynaptic input on Purkinje cells. Mossy fibers, also excitatory, are axons of all other sources and synapse on granule cells. What four CN carry preganglionic parasympathetic fibers? - Answer CN III, VII, IX, and X