Muscles: True/False & Multiple Choice

True/False statements

• Synergists are muscles that assist an agonist in performing a movement
• Contraction of the rectus abdominis does not result in rotation of the vertebral column
• The internal and external oblique muscles both insert on the linea alba
• Muscles of the vertebral column are not simple, and have more than one attachment
• Vertical dimensions of the thoracic cavity decrease as the diaphragm contracts
• The flexor pollicis longus muscle does not attach proximally to the medial epicondyle of the humerus
• Most muscles within the medial compartment of the thigh adduct the thigh
• Hamstring muscles extend the thigh
• The quadriceps femoris do not flex the leg

Multiple choice/Check all that apply statements

• When a muscle fiber is at rest:
• There is a charge difference across the sarcolemma
• Sodium-potassium pumps are active
• Calcium is stored in the sarcoplasm
• Extensibility is the characteristic of muscle that allows it to be passively stretched
• Possible functions of skeletal muscles:
• Maintenance of posture.
• Both highly coordinated and localized simple movements.
• Temperature regulation.
• Support of certain body organs.
• Regulation of the movement of material through certain body tracts.
• Conductivity is the property of muscle tissue allowing an impulse to travel down the entire length of the cell membrane
• The hierarchy of skeletal muscle’s components from smallest to largest: Myofibrils, muscle fiber, fascicle, skeletal muscle
• Correct order of connective tissue layers of a skeletal muscle, beginning with the most superficial: Epimysium, perimysium, endomysium
• A tendon is responsible for attaching muscle to bone
• A flat, thin structure made of dense connective tissue to attach a muscle to a bone (or to another muscle) is an aponeurosis
• Motor neurons stimulate muscle contraction
• The membranous network that warps around myofibrils and holds calcium is the sarcoplasmic reticulum
• Invaginations of the muscle cell membrane extending deep into the cell are known as T-tubules
• Myosin makes up thick filaments
• Myosin is not a protein in thin filaments
• The letter A is associated with the dark bands in a sarcomere
• The letter is associated with thin protein structures serving as an attachment site for thin filament ends. Double check this one- the text had what looks to be a typo
• The letter H is a zone in a relaxed muscle and it is a little more lightly shaded with only thick filaments
• The letter I is associated with the light band and contains thin filaments only
• Actin has the active sites to which the heads of the thick filaments will bind
• A sarcomere is defined as the distance from one Z disc to the next adjacen Z disc
• Myoglobin is a molecule that can bind to oxygen in muscle cells
• The presence of mitochondria and myoglobin facilitate aerobic respiration
• The narrow space separating the motor neuron and skeletal muscle fiber in a neuromuscular junction is called the synaptic cleft
• Synaptic vesicles are the reservoirs that store acetylcholine
• Calcium enters through voltage-gated channels upon impulse arrival, triggering the release of the transmitter from the motor neuron knob
• Acetylcholine exerts its effect by binding to receptors at the motor end plate
• Acetylcholine is a neurotransmitter causing the release of calcium ions from reservoirs within the muscle cell, initiating the steps of contraction
• Calcium ions in skeletal muscle contraction bind to troponin
• Muscle fiber action potentials occur along the sarcolemma and down the T-tubules
• Repolarization of the action potential involves the opening of voltage-gated K+ channels
• Sequence of changes for sliding thick and thin filaments: Attach - pivot - detach - return
• A power stroke involves a myosin head pulling a thin filament toward the center of the sarcomere
• A drug that inhibits acetylcholinesterase results in enhanced muscle stimulation due to decreased ACh breakdown
• For relaxation to occur: ACh receptors close and Ca++ channels on the sarcoplasmic reticulum close
• For relaxation to occur: sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin
• When a muscle relaxes: crossbridges stop forming and muscle elasticity returns the muscle to rest length
• Glycolysis is an anaerobic process in the cytosol
• The net energy yield from one glucose molecule through the process of glycolysis is 2 ATP
• Oxidative fibers are red and fatigue-resistant
• Slow-twitch fibers are specialized for extended contraction, useful in events such as marathon running
• "Intermediate fiber" is another name for a fast-twitch, oxidative fiber
• Slow-twitch fibers are dominant in body-positioning muscles i.e back and calf muscles
• Muscles of the eye and hand have a high percentage of fast-twitch fibers, for quick, responsive movements
• Events of excitation contraction coupling, such as calcium are released during the latent period of a muscle twitch
• Crossbridge release and a decline in muscle tension characterize the relaxation period of a twitch
• Muscle tone results from involuntary nervous system activity, stabilizing a joint position
• Isometric contraction occurs when trying unsuccessfully to move a wall
• Fast-twitch fibers are the most prevalent of skeletal muscle fibers
• Increased phosphate ion concentration is believed to cause fatigue by interfering with phosphate release by myosin heads during crossbridge cycling
• With increased age, skeletal muscles show a decrease in the number of myofibrils
• Lifting weights primarily causes muscles to enlarge due to an increase in the size of muscle cells
• Atrophy describes the change in muscle following a lack of exercise
• Smooth muscle fibers have only one nucleus and have both thick and thin filaments, but no Z discs
• Smooth muscle tissue sending individual signals to contract (not in unison) is multiunit
• The iris of the eye (nonstriated and involuntarily controlled muscle) must contain multiunit smooth muscle
• Single-unit smooth muscle, also known as visceral smooth muscle, is the most abundant form of smooth muscle
• Striated muscle fibers forming Y-shaped branches, joined by intercalated discs are cardiac muscle
• Multiunit smooth muscle is innervated most similarly to skeletal muscle with muscle cells arranged as motor units and each cell stimulated by a single motor neuron
• An antagonist muscle opposes the action of the prime mover
• For elbow flexion: the biceps brachii is the agonist and triceps brachii is the antagonist
• The word "biceps" describes the muscle has two tendons of origin
• When a person blinks, the muscle they are using is their orbicularis oculi
• The "kiss muscle," used for puckering the lips, is the Orbicularis oris
• A nursing baby uses the buccinator muscle to suckle
• Shifting of eyes caused by a sharp noise requires the left eye's lateral rectus and the right eye's medial rectus
• The superior oblique extrinsic eye mucle moves through a pulleylike loop
• The lateral rectus extrinsic eye muscle is innervated by the abducens nerve (CN VI)
• The trochlear nerve innervates the superior oblique muscle
• Four muscles of mastication: Masseter, temporalis, lateral pterygoid, medial pterygoid
• Genioglossus does not move the mandible
• The ending “glossus” refers to the tongue
• Pharyngeal constrictor muscles are important for swallowing
• The sternocleidomastoid has has its inferior attachment on the manubrium and sternal end of the clavicle and its superior attachment on the mastoid process
• Unilateral contraction of the right sternocleidomastoid results in lateral flexion of the head to the right and rotation of the head to the left
• External intercostals elevate the ribs, originating on the inferior border of a superior rib and inserting on the superior border of the inferior rib
• When contracted, the diaphragm causes expansion of the thoracic cavity but an increase in pressure in the abdominopelvic cavity
• The diaphragm forms a partition between the thoracic and abdominal cavities
• External intercostals elevate the ribs
• The deepest of the abdominal muscles are the transversus abdominis
• The rectus abdominis forms the traditional "six-pack" of a well-toned abdominal wall
• Tendinous intersections are fibrous, perpendicular insertions betweensuccessive sheets or blocks of muscle
• The rectus abdominis are abdominal muscles innervated by spinal nerves T7–T12
• The external oblique abdominal muscles has its fibers running in an inferomedial direction
• The external urethral sphincter is part of the urogenital diaphragm, constricting the urethra to voluntarily inhibit urination
• The anterior border of the perineum is the pubic symphysis
• Muscles that arise from the skull and attach to the skin are muscles that move the tongue
• Muscles of mastication help us in the initial breakdown of food
• Muscles of the pectoral girdle attach proximally on the axial skeleton and attach distally on the clavicle and scapula
• The rhomboid major muscle elevates and retracts (adducts) the scapula
• The serratus anterior is a large, saw-toothed, flat, fan-shaped muscle positioned between the ribs and the scapula
• Muscles moving the glenohumeral joint attached proximally on the axial skeleton include the latissimus dorsi and pectoralis major
• The supraspinatus is the exception to all the listed muscles that adduct the arm
• The pectoralis major is an exception to most muscles’ proximal attachment on the scapula.
• The triceps brachii are the muscles that move the glenohumeral joint but do not attach distally to the humerus
• The principal elbow flexors on the anterior side of the humerus are biceps brachii, brachialis, and brachioradialis
• When a baseball pitcher winds up to throw, they medially rotate their arm by contracting thier subscapularis
• The teres major is not one of the rotator cuff muscles
• The Latissimus dorsi as the “swimmer's muscle"
• The prime extensor of the elbow joint is the triceps brachii
• The pronator teres is not innervated by the radial nerve
• Besides the supinator, the biceps brachii is a powerful supinator of the forearm
• Many anterior forearm muscles that flex the wrist have a proximal attachment on the medial epicondyle of the humerus
• The flexor pollicis longus in the anterior compartment of the forearm is located on the deep layer
• Tennis elbow is caused by damage to the common extensor tendon of the posterior forearm muscles
• The extensor digitorum muscle is in the superficial layer of the posterior compartment of the forearm
• Thenar group muscles form a thick, fleshy mass at the base of the thumb
• Adductor pollicis would bring your thumb toward your first finger if all fingers have been spread wide
• Palmar interossei would bring fingers 2-5 together if all fingers (including the thumb) have been spread out wide
• When a child raises her hand to show you she is five years old, she is using all of the following muscles except the flexor digitorum
• The gluteus maximus is one of the largest muscles in the body and the one most responsible for extending and laterally rotating the thigh
• Rectus femoris is not one of the hamstring muscles
• Adductor longus does not attach proximally to the ischial tuberosity
• Biceps femoris attaches distally to the head of the fibula
• The sartorius is the longest muscle of the body
• Biceps femoris functions to extend the thigh and flex the leg
• The quadriceps femoris is the primary action in extending the leg for kicking in soccer
• Crural muscles are those that move the ankle, foot, and toes
• The tibialis anterior is the primary dorsiflexor of the foot at the ankle
• The extensor hallucis longus is located in the anterior compartment of the leg
• Anterior compartment leg muscles function to dorsiflex the foot and extend the toes
• The soleus is exposed when the gastrocnemius muscle is removed
• The gastrocnemius and soleus are known as the triceps surae and together are the most powerful plantar flexors of all of the leg muscles
• The gastrocnemius are not innervated by the deep fibular nerve
• The flexor digitorum longus is located in the deep layer of the posterior compartment of the leg, and it flexes toes 2–5
• The gastrocnemius and soleus attach distally to the calcaneal tendon
• The extensor digitorum brevis muscle is not innervated by the plantar nerve
• The gluteus medius abducts the thigh

Muscles associated with figure labels

• #1 upper limb muscle: Brachioradialis
• #1 right thigh muscle (anterior view): Gracilis
• #1 right thigh muscle (lateral view): Vastus lateralis
• #1 muscles with facial expression: Platysma
• #2 muscles with facial expression: Nasalis
• #3 muscles with facial expression: Orbicularis oculi
• #4 muscles with facial expression: Masseter
• #5 muscles with facial expression: Buccinator
• #6 muscles with facial expression: Orbicularis oris
• #7 muscles with facial expression: Levator labii superioris
• #8 muscles with facial expression: Mentalis
• #9 muscles with facial expression: Depressor labii inferioris
• #1 muscles with facial expression (lateral view): Masseter
• #2 muscles with facial expression (lateral view): Temporalis
• #3 muscles with facial expression (lateral view): Buccinator
• #4 muscles with facial expression (lateral view): Platysma
• #5 muscles with facial expression (lateral view): Sternocleidomastoid
• #2 muscle shown: Superior oblique
• #3 muscle shown: medial rectus
• #4 structure shown: Trochlea
• #1 muscle: lateral rectus
• #2 muscle: medial rectus
• #4 feature: Optic Canal
• #1 muscle movement for the tongue: Hyoglossus
• #2 muscles movement for the tongue: Genioglossus
• #3 muscles movement for the tongue: Stylohyoid
• #1 muscle anterior neck: Trapezius
• #2 muscle anterior neck: Sternohyoid
• #3 muscle anterior neck: Sternocleidomastoid
• #1 muscles of respiration: Internal intercostals
• #2 muscle of respiration: External Intercostols
• #3 muscles of respiration: Scalenes
• #4 muscle of respiration: Diaphragm
• #2 abdominal muscle: Rectus abdominis
• #3 abdominal muscle: Linea alba
• #1 muscle anterior trunk: Pectoralis major
• #3 muscle anterior trunk: Pectoralis minor
• #1 muscle posterior trunk: Trapezius
• #3 muscle posterior trunk: Rhomboid major
• #2 muscle posterior trunk: Infraspinatus
• #1 muscle deep arm muscles: Brachialis
• #2 muscle deep arm muscles: Coracobrachialis
• #1 muscle right anterior forearm: Pronator Teres
• #2 muscle right anterior forearm: Palmaris longus
• #3 muscle right anterior forearm: Flexor carpi radialis
• #1 muscle view of hand: Lumbrical #2-# muscle view of hand: Abductor pollicis brevis
• #1 muscle view of right thigh: Semimembranosus
• #2 muscle view of right thigh: Semitendinosus
• #3 muscle view of right thigh: Adductor magnus
• #1 muscle of the view of the right leg: Tibialis anterior
• #2 muscle of the view of the right leg: Soleus
• #3 muscle of the view of the right leg: Fibularis longus

Fill in the blank question solutions

• Relaxation is facilitated by the release of passive tension that developed in cablelike CONNECTIN proteins that were compressed during contraction.
• The muscles between the ribs that function to depress the ribs during forced expiration (exhalation) are the INTERNAL intercostal muscles.
• The muscles that form the fleshy mass at the base of the little finger are known as the HYPOTHENAR group.
• The large muscle in the calf that has lateral and medial heads is the GASTROCNEMIUS