BIOL 235 Midterm 2 Exam 2026/2027 COMPREHENSIVE
REVIEW AND DETAILED EXPLANATIONS
• insertion -✓✓ The attachment of a muscle tendon to a moveable bone
opposite of the origin
• Belly (body) -✓✓ the fleshy portion of the muscle between the tendons
• Reverse Muscle Action (RMA) -✓✓ during specific movements of the body the actions
are reversed; therefore, the positions of the origin and insertion of a specific muscle are
switched.
• Fulcrum -✓✓ fixed point on a lever
• Effort -✓✓ causes the movement
force exerted by muscle contraction
• Load -✓✓ opposes the movement
• Mechanical Advantage (MA) -✓✓ load is closer to the fulcrum and effort is farther from
the fulcrum
only a small amount of effort needed to move the load over a small distance
• mechanical disadvantage -✓✓ load is farther from fulcrum than effort applied,
large effort is required to move a small load
• First class levers -✓✓ The fulcrum is between the effort and the load
ex: see saw, scissors
can produce a mechanical advantage and disadvantage
in the body: head sitting on the Atlanto-axial joint
• second class levers -✓✓ the load is closer to the fulcrum than the effort
like a wheelbarrow
always produce mechanical advantage, sacrifices speed for force
ex: standing up on your toes
• third class levers -✓✓ The effort is between the fulcrum and the load
always produce a mechanical disadvantage
ex: biceps brachii muscle
• prime mover (agonist) -✓✓ muscle that contracts to produce a particular movement
• antagonist muscle -✓✓ Stretches and yeilds to the effects of the prime mover
,• Syngerists -✓✓ - aid the movement of the prime mover
contract and stabilize the intermediate joints
prevent any unwanted movements
• Fixators -✓✓ Stabilize the origin of the prime mover so that the prime mover can act
more efficiently
• Compartment -✓✓ A group of skeletal muscles, their associated blood vessels, and
associated nerves, all of which have a common function
• fusiform fascicle -✓✓ fascicles run parallel to long axis of muscle but converge at the
ends forming a spindle shape
belly is larger
• pennate fascicles -✓✓ short fascicles in relation to total muscle length; tendon extends
nearly entire length of muscle
- uni, bi, and multi
• Rectus -✓✓ Parallell to midline
• Brevis -✓✓ short
• Occipitofrontalis (frontal belly) -✓✓ raises eyebrows, wrinkles forehead
draws scalp anteriorly
• Occipitofrontalis (occipital belly) -✓✓ - at the back of the head, superficial to occipital
bone
- draws scalp posteriorly
• Orbicularis oris -✓✓ - muscles circling the mouth
- shapes lips in speech, closes and protrudes lips
• zygomaticus major -✓✓ draws mouth superiorly and laterally: smiling
on the cheekbone
• Buccinator -✓✓ major muscular portion of the cheek
compresses the cheeks: blowing, sucking, assists in chewing
• orbicularis oculi -✓✓ closes the eyes
circular muscle around the eyes
• Massester -✓✓ Origin: maxilla & zygomatic arch
Insertion: Angle & ramus of mandible
,Elevates mandible, closing mouth
*strongest muscle of mastication
• Temporalis -✓✓ Origin: Temporal bone
Insertion: coronoid process and ramus of mandible
Elevates & retracts mandible
• Sternocleidomastoid -✓✓ origin: manubrium and clavicle
insertion: mastoid process of temporal bone
Flex the cervical portion of vertebral column, flexes laterally and rotates head
*divides the neck into triangles
• Rectus Abdominis -✓✓ Origin: pubic crest and symphysis
Insertion: xiphoid process and costal cartilages of ribs 5-7
Action: flexes and rotates vertebral column, compress abdomen, aid in defecation,
urination
• External Oblique -✓✓ Compresses abdomen; laterally flexes and rotates vertebral
column
Diagonal to midline, superficial muscle
• Internal Oblique -✓✓ Intermediate flat muscle
Compress abdomen, laterally flex and rotate vertebral column
• Transversus Abdominis -✓✓ Transverse around the abdominal wall, deep muscle
Compress the abdomen
• Diaphragm -✓✓ Dome shaped muscle that powers breathing
• External Intercostal -✓✓ Occupy the superficial layer
elevate ribs during inhalation= expanding thoracic cavity
• Internal Intercostals -✓✓ Occupy the intermediate layer
draw ribs together during exhalation = decreases size of thoracic cavity
• Pectoralis Minor -✓✓ abducts scapula and rotates it downward
assists in forced inhalation (elevating ribs 3-5)
• Trapezius -✓✓ -Origin: spinous processes of vertebrae C7-T12
-Insertion: Clavicle and acromion + spine of scapula
-Rotate scapula upwards, adduct, depress scapula
• levator scapulae -✓✓ origin: transverse processes of C1-C4
insertion: superior vertebral border of scapula
Elevates and rotates scapula downward
, posterior portion of the neck
• rhomoid major -✓✓ Diamond shaped, lie deep to the trapezius
stabilizes scapula, rotates it up and downward
• pectoralis major -✓✓ Origin: Clavicular head, sternum, costal cartilages of ribs 2-6
Insertion: Greater tubercle of humerus
Adducts and medially rotates arm, extends arm to the side of trunk
• latissimus dorsi -✓✓ Extends, adducts, and medially rotates the arm; draws the
shoulder downward and backward
elevates vertebral column and torso
• Deltoid -✓✓ Origin: acromial extremity of clavicle, acromion of scapula
Insertion: deltoid tuberosity of humerus
Abduct arm, laterally and medially rotate arm,
• Subscapularis -✓✓ medially rotates arm at shoulder joint
fills the sub scapular fossa, below the scapula
• Supraspinatus -✓✓ lies deep in the trapezius, superior to scapula
origin: supraspinous fossa of scapula
insertion: greater tubercle of humerus
assists deltoid muscle in abducting the arm
• Infraspinatus -✓✓ rotates arm laterally
• teres major -✓✓ Assists the extension of the humerus, medially rotates and adducts
the humerus
helps form the wall of the axilla
• teres minor -✓✓ laterally rotates and extends arm at shoulder joint
lies on top of the teres major
• biceps brachii -✓✓ Origin: tubercle above glenoid cavity of scapula (long), coracoid
process of scapula (short)
Insertion: Radial tuberosity of radius
Flexes and supinates arm
2 heads of origin
• Brachialis -✓✓ flexes forearm at elbow joint
is the "workhorse" of the elbow
• Brachioradialis -✓✓ flexes forearm, supinates and pronates forearm
REVIEW AND DETAILED EXPLANATIONS
• insertion -✓✓ The attachment of a muscle tendon to a moveable bone
opposite of the origin
• Belly (body) -✓✓ the fleshy portion of the muscle between the tendons
• Reverse Muscle Action (RMA) -✓✓ during specific movements of the body the actions
are reversed; therefore, the positions of the origin and insertion of a specific muscle are
switched.
• Fulcrum -✓✓ fixed point on a lever
• Effort -✓✓ causes the movement
force exerted by muscle contraction
• Load -✓✓ opposes the movement
• Mechanical Advantage (MA) -✓✓ load is closer to the fulcrum and effort is farther from
the fulcrum
only a small amount of effort needed to move the load over a small distance
• mechanical disadvantage -✓✓ load is farther from fulcrum than effort applied,
large effort is required to move a small load
• First class levers -✓✓ The fulcrum is between the effort and the load
ex: see saw, scissors
can produce a mechanical advantage and disadvantage
in the body: head sitting on the Atlanto-axial joint
• second class levers -✓✓ the load is closer to the fulcrum than the effort
like a wheelbarrow
always produce mechanical advantage, sacrifices speed for force
ex: standing up on your toes
• third class levers -✓✓ The effort is between the fulcrum and the load
always produce a mechanical disadvantage
ex: biceps brachii muscle
• prime mover (agonist) -✓✓ muscle that contracts to produce a particular movement
• antagonist muscle -✓✓ Stretches and yeilds to the effects of the prime mover
,• Syngerists -✓✓ - aid the movement of the prime mover
contract and stabilize the intermediate joints
prevent any unwanted movements
• Fixators -✓✓ Stabilize the origin of the prime mover so that the prime mover can act
more efficiently
• Compartment -✓✓ A group of skeletal muscles, their associated blood vessels, and
associated nerves, all of which have a common function
• fusiform fascicle -✓✓ fascicles run parallel to long axis of muscle but converge at the
ends forming a spindle shape
belly is larger
• pennate fascicles -✓✓ short fascicles in relation to total muscle length; tendon extends
nearly entire length of muscle
- uni, bi, and multi
• Rectus -✓✓ Parallell to midline
• Brevis -✓✓ short
• Occipitofrontalis (frontal belly) -✓✓ raises eyebrows, wrinkles forehead
draws scalp anteriorly
• Occipitofrontalis (occipital belly) -✓✓ - at the back of the head, superficial to occipital
bone
- draws scalp posteriorly
• Orbicularis oris -✓✓ - muscles circling the mouth
- shapes lips in speech, closes and protrudes lips
• zygomaticus major -✓✓ draws mouth superiorly and laterally: smiling
on the cheekbone
• Buccinator -✓✓ major muscular portion of the cheek
compresses the cheeks: blowing, sucking, assists in chewing
• orbicularis oculi -✓✓ closes the eyes
circular muscle around the eyes
• Massester -✓✓ Origin: maxilla & zygomatic arch
Insertion: Angle & ramus of mandible
,Elevates mandible, closing mouth
*strongest muscle of mastication
• Temporalis -✓✓ Origin: Temporal bone
Insertion: coronoid process and ramus of mandible
Elevates & retracts mandible
• Sternocleidomastoid -✓✓ origin: manubrium and clavicle
insertion: mastoid process of temporal bone
Flex the cervical portion of vertebral column, flexes laterally and rotates head
*divides the neck into triangles
• Rectus Abdominis -✓✓ Origin: pubic crest and symphysis
Insertion: xiphoid process and costal cartilages of ribs 5-7
Action: flexes and rotates vertebral column, compress abdomen, aid in defecation,
urination
• External Oblique -✓✓ Compresses abdomen; laterally flexes and rotates vertebral
column
Diagonal to midline, superficial muscle
• Internal Oblique -✓✓ Intermediate flat muscle
Compress abdomen, laterally flex and rotate vertebral column
• Transversus Abdominis -✓✓ Transverse around the abdominal wall, deep muscle
Compress the abdomen
• Diaphragm -✓✓ Dome shaped muscle that powers breathing
• External Intercostal -✓✓ Occupy the superficial layer
elevate ribs during inhalation= expanding thoracic cavity
• Internal Intercostals -✓✓ Occupy the intermediate layer
draw ribs together during exhalation = decreases size of thoracic cavity
• Pectoralis Minor -✓✓ abducts scapula and rotates it downward
assists in forced inhalation (elevating ribs 3-5)
• Trapezius -✓✓ -Origin: spinous processes of vertebrae C7-T12
-Insertion: Clavicle and acromion + spine of scapula
-Rotate scapula upwards, adduct, depress scapula
• levator scapulae -✓✓ origin: transverse processes of C1-C4
insertion: superior vertebral border of scapula
Elevates and rotates scapula downward
, posterior portion of the neck
• rhomoid major -✓✓ Diamond shaped, lie deep to the trapezius
stabilizes scapula, rotates it up and downward
• pectoralis major -✓✓ Origin: Clavicular head, sternum, costal cartilages of ribs 2-6
Insertion: Greater tubercle of humerus
Adducts and medially rotates arm, extends arm to the side of trunk
• latissimus dorsi -✓✓ Extends, adducts, and medially rotates the arm; draws the
shoulder downward and backward
elevates vertebral column and torso
• Deltoid -✓✓ Origin: acromial extremity of clavicle, acromion of scapula
Insertion: deltoid tuberosity of humerus
Abduct arm, laterally and medially rotate arm,
• Subscapularis -✓✓ medially rotates arm at shoulder joint
fills the sub scapular fossa, below the scapula
• Supraspinatus -✓✓ lies deep in the trapezius, superior to scapula
origin: supraspinous fossa of scapula
insertion: greater tubercle of humerus
assists deltoid muscle in abducting the arm
• Infraspinatus -✓✓ rotates arm laterally
• teres major -✓✓ Assists the extension of the humerus, medially rotates and adducts
the humerus
helps form the wall of the axilla
• teres minor -✓✓ laterally rotates and extends arm at shoulder joint
lies on top of the teres major
• biceps brachii -✓✓ Origin: tubercle above glenoid cavity of scapula (long), coracoid
process of scapula (short)
Insertion: Radial tuberosity of radius
Flexes and supinates arm
2 heads of origin
• Brachialis -✓✓ flexes forearm at elbow joint
is the "workhorse" of the elbow
• Brachioradialis -✓✓ flexes forearm, supinates and pronates forearm
