BIOS 252 Week 8 Final Exam | 2025|
Chamberlain University| Actual Exam
Questions and Correct Answers
1. Define spinal reflex and provide an example from the body to illustrate it.
Answer: A spinal reflex is an involuntary, rapid response to a stimulus mediated by the spinal
cord without brain involvement. Example: Patellar reflex—tapping the patellar tendon stretches
the quadriceps, triggering sensory neurons to signal motor neurons in the spinal cord, causing leg
extension.
Explanation: The reflex arc (receptor → sensory neuron → motor neuron → effector) bypasses
the brain for speed, as seen in the monosynaptic patellar reflex, which maintains posture.
2. Describe sleep, its major stages, and contrast it with coma (similarities and differences).
Answer: Sleep is a reversible state of reduced consciousness with four stages: Non-REM (Stage
1: light sleep; Stage 2: deeper, spindles; Stage 3: deep, delta waves) and REM (dreaming, muscle
atonia). Similarities with coma: reduced consciousness, minimal movement. Differences: sleep is
cyclical, reversible, purposeful (memory consolidation); coma is pathological, prolonged,
unarousable, with no sleep cycles.
Explanation: Sleep involves organized EEG patterns and active brain functions, unlike coma’s
diffuse slowing, reflecting their distinct physiological roles.
3. Explain language usage and comprehension, including the two major language areas of the
brain, their location, specialization, and effects of damage.
Answer: Language usage (expression) and comprehension (understanding) rely on:
Broca’s Area: Posterior inferior frontal gyrus (left); speech production, grammar. Damage:
Broca’s aphasia (halting speech, preserved comprehension).
Wernicke’s Area: Posterior superior temporal gyrus (left); comprehension, semantics. Damage:
Wernicke’s aphasia (fluent, nonsensical speech, poor comprehension).
Explanation: These areas, connected by the arcuate fasciculus, specialize in distinct language
functions, and damage disrupts specific aspects, highlighting their roles.
,4. Compare and contrast the cochlea and vestibular apparatus (anatomical and physiological
differences).
Answer:
Cochlea: Spiral, three chambers, organ of Corti with hair cells; detects sound vibrations,
transduces to cochlear nerve (hearing).
Vestibular Apparatus: Utricle, saccule, semicircular canals; hair cells in maculae (linear motion)
and cristae (angular); transduces to vestibular nerve (balance).
Anatomical: Cochlea is coiled; vestibular has otoliths/cupulae. Physiological: Cochlea for sound
frequency; vestibular for motion/gravity.
Explanation: Both use hair cells for mechanotransduction but differ in structure (coiled vs.
chambers) and function (auditory vs. equilibrium).
5. Explain how light reflecting off an object passes through the eye, including relevant structures
and photon transduction into an electrochemical signal, with major regions involved.
Answer: Light passes: cornea (refracts) → aqueous humor → pupil (regulates) → lens (focuses)
→ vitreous humor → retina (photoreceptors). Transduction: Photons activate rhodopsin
(rods)/photopsins (cones), hyperpolarizing cells, signaling bipolar → ganglion cells → optic
nerve. Regions: Retina (transduction), optic nerve/tract, LGN (thalamus), visual cortex
(occipital).
Explanation: Refraction focuses light; retinal photoreceptors convert photons to signals, relayed
via thalamus to cortex for visual processing.
6. Explain the control of estrogen and progesterone through the endocrine system.
Answer: Hypothalamus releases GnRH → pituitary secretes FSH/LH → ovaries produce
estrogen (follicles) and progesterone (corpus luteum). Estrogen rises, inhibits FSH/LH (negative
feedback), then triggers LH surge (positive feedback) for ovulation. Progesterone prepares
uterus; high levels inhibit GnRH.
Explanation: The HPG axis uses feedback loops to regulate ovarian hormones, balancing
reproductive cycles.
7. Explain calcium regulation in the body using homeostasis and negative feedback.
Answer: Blood Ca²⁺ maintained (~8.5-10.5 mg/dL) via: Low Ca²⁺ → parathyroid releases PTH
→ bone resorption, kidney reabsorption, vitamin D activation (intestinal absorption). High Ca²⁺
, → thyroid releases calcitonin → bone deposition, kidney excretion. Negative feedback restores
balance.
Explanation: Sensors (parathyroid/thyroid) detect deviations, triggering effectors (bones,
kidneys) to counteract changes, maintaining homeostasis.
8. How is sugar regulated in the body (up- and downregulation)?
Answer: Upregulation: Low glucose → pancreatic alpha cells release glucagon → liver
glycogenolysis/gluconeogenesis → raises glucose. Downregulation: High glucose → beta cells
release insulin → cell uptake, glycogenesis → lowers glucose.
Explanation: Pancreas hormones (insulin/glucagon) use negative feedback to stabilize blood
glucose, preventing hypo/hyperglycemia.
9. Discriminate between paracrine, autocrine, endocrine, and exocrine secretions.
Answer:
Paracrine: Local; affects nearby cells (e.g., histamine in inflammation).
Autocrine: Self; acts on same cell (e.g., cancer growth factors).
Endocrine: Blood-borne hormones; distant targets (e.g., insulin).
Exocrine: Ducts to surfaces (e.g., salivary amylase).
Explanation: These secretions differ in target distance and delivery (local, self, systemic, or
external).
10. Describe each endocrine gland, its hormone(s), function(s), and regulation.
Answer:
Hypothalamus: GnRH, CRH (pituitary control); neural/hormonal feedback.
Anterior Pituitary: FSH/LH (reproduction), ACTH (stress), TSH (thyroid), GH (growth),
prolactin (milk); hypothalamic hormones.
Posterior Pituitary: ADH (water), oxytocin (contraction); neural.
Thyroid: T3/T4 (metabolism), calcitonin (Ca²⁺); TSH/Ca²⁺.
Parathyroid: PTH (Ca²⁺); blood Ca²⁺.
Adrenal Cortex: Cortisol (stress), aldosterone (Na⁺), androgens; ACTH/renin.
Adrenal Medulla: Epinephrine (fight-or-flight); sympathetic nerves.
Chamberlain University| Actual Exam
Questions and Correct Answers
1. Define spinal reflex and provide an example from the body to illustrate it.
Answer: A spinal reflex is an involuntary, rapid response to a stimulus mediated by the spinal
cord without brain involvement. Example: Patellar reflex—tapping the patellar tendon stretches
the quadriceps, triggering sensory neurons to signal motor neurons in the spinal cord, causing leg
extension.
Explanation: The reflex arc (receptor → sensory neuron → motor neuron → effector) bypasses
the brain for speed, as seen in the monosynaptic patellar reflex, which maintains posture.
2. Describe sleep, its major stages, and contrast it with coma (similarities and differences).
Answer: Sleep is a reversible state of reduced consciousness with four stages: Non-REM (Stage
1: light sleep; Stage 2: deeper, spindles; Stage 3: deep, delta waves) and REM (dreaming, muscle
atonia). Similarities with coma: reduced consciousness, minimal movement. Differences: sleep is
cyclical, reversible, purposeful (memory consolidation); coma is pathological, prolonged,
unarousable, with no sleep cycles.
Explanation: Sleep involves organized EEG patterns and active brain functions, unlike coma’s
diffuse slowing, reflecting their distinct physiological roles.
3. Explain language usage and comprehension, including the two major language areas of the
brain, their location, specialization, and effects of damage.
Answer: Language usage (expression) and comprehension (understanding) rely on:
Broca’s Area: Posterior inferior frontal gyrus (left); speech production, grammar. Damage:
Broca’s aphasia (halting speech, preserved comprehension).
Wernicke’s Area: Posterior superior temporal gyrus (left); comprehension, semantics. Damage:
Wernicke’s aphasia (fluent, nonsensical speech, poor comprehension).
Explanation: These areas, connected by the arcuate fasciculus, specialize in distinct language
functions, and damage disrupts specific aspects, highlighting their roles.
,4. Compare and contrast the cochlea and vestibular apparatus (anatomical and physiological
differences).
Answer:
Cochlea: Spiral, three chambers, organ of Corti with hair cells; detects sound vibrations,
transduces to cochlear nerve (hearing).
Vestibular Apparatus: Utricle, saccule, semicircular canals; hair cells in maculae (linear motion)
and cristae (angular); transduces to vestibular nerve (balance).
Anatomical: Cochlea is coiled; vestibular has otoliths/cupulae. Physiological: Cochlea for sound
frequency; vestibular for motion/gravity.
Explanation: Both use hair cells for mechanotransduction but differ in structure (coiled vs.
chambers) and function (auditory vs. equilibrium).
5. Explain how light reflecting off an object passes through the eye, including relevant structures
and photon transduction into an electrochemical signal, with major regions involved.
Answer: Light passes: cornea (refracts) → aqueous humor → pupil (regulates) → lens (focuses)
→ vitreous humor → retina (photoreceptors). Transduction: Photons activate rhodopsin
(rods)/photopsins (cones), hyperpolarizing cells, signaling bipolar → ganglion cells → optic
nerve. Regions: Retina (transduction), optic nerve/tract, LGN (thalamus), visual cortex
(occipital).
Explanation: Refraction focuses light; retinal photoreceptors convert photons to signals, relayed
via thalamus to cortex for visual processing.
6. Explain the control of estrogen and progesterone through the endocrine system.
Answer: Hypothalamus releases GnRH → pituitary secretes FSH/LH → ovaries produce
estrogen (follicles) and progesterone (corpus luteum). Estrogen rises, inhibits FSH/LH (negative
feedback), then triggers LH surge (positive feedback) for ovulation. Progesterone prepares
uterus; high levels inhibit GnRH.
Explanation: The HPG axis uses feedback loops to regulate ovarian hormones, balancing
reproductive cycles.
7. Explain calcium regulation in the body using homeostasis and negative feedback.
Answer: Blood Ca²⁺ maintained (~8.5-10.5 mg/dL) via: Low Ca²⁺ → parathyroid releases PTH
→ bone resorption, kidney reabsorption, vitamin D activation (intestinal absorption). High Ca²⁺
, → thyroid releases calcitonin → bone deposition, kidney excretion. Negative feedback restores
balance.
Explanation: Sensors (parathyroid/thyroid) detect deviations, triggering effectors (bones,
kidneys) to counteract changes, maintaining homeostasis.
8. How is sugar regulated in the body (up- and downregulation)?
Answer: Upregulation: Low glucose → pancreatic alpha cells release glucagon → liver
glycogenolysis/gluconeogenesis → raises glucose. Downregulation: High glucose → beta cells
release insulin → cell uptake, glycogenesis → lowers glucose.
Explanation: Pancreas hormones (insulin/glucagon) use negative feedback to stabilize blood
glucose, preventing hypo/hyperglycemia.
9. Discriminate between paracrine, autocrine, endocrine, and exocrine secretions.
Answer:
Paracrine: Local; affects nearby cells (e.g., histamine in inflammation).
Autocrine: Self; acts on same cell (e.g., cancer growth factors).
Endocrine: Blood-borne hormones; distant targets (e.g., insulin).
Exocrine: Ducts to surfaces (e.g., salivary amylase).
Explanation: These secretions differ in target distance and delivery (local, self, systemic, or
external).
10. Describe each endocrine gland, its hormone(s), function(s), and regulation.
Answer:
Hypothalamus: GnRH, CRH (pituitary control); neural/hormonal feedback.
Anterior Pituitary: FSH/LH (reproduction), ACTH (stress), TSH (thyroid), GH (growth),
prolactin (milk); hypothalamic hormones.
Posterior Pituitary: ADH (water), oxytocin (contraction); neural.
Thyroid: T3/T4 (metabolism), calcitonin (Ca²⁺); TSH/Ca²⁺.
Parathyroid: PTH (Ca²⁺); blood Ca²⁺.
Adrenal Cortex: Cortisol (stress), aldosterone (Na⁺), androgens; ACTH/renin.
Adrenal Medulla: Epinephrine (fight-or-flight); sympathetic nerves.
