A&P 1 Muscles

Which muscle's most powerful action is to supinate the forearm?

Biceps Bracchii - The largest muscle on anterior arm

What is the prime mover that flexes the forearm?

Brachialis muscle

_______________________________ is the synergist that flexes the forearm.

Brachioradialis muscle

Which type of muscle works together with the agonist?

Synergist

Which of the following is not a muscle of the rotator cuff?

Teres Major The Four muscles belong to the rotator cuff group: the supraspinatus, infraspinatus, teres minor, and subscapularis.

What two muscles are the principle lateral rotators of the arm?

Teres minor and infraspinatus

Myofilaments

The contractile proteins, actin and myosin, of muscle cells

Which Muscle is responsible for thumbs up

The extensor pollicis longus muscle extends the thumb in a ________________________________________

Agonist muscle

The muscle primarily responsible for movement of a bone.

What muscle protracts and depresses the scapula?

The pectoralis minor

What is the Key muscle in throwing a punch

The serratus anterior muscle is the prime mover of scapulain protraction.

________________________________muscle extends the forearm

Triceps brachii

Synergists, as their name implies, work together with the agonist. True or false

True

The antagonist usually lies on the opposite side of a joint from its agonist partner and tends to oppose and slow the action. True or false

True

Triceps brachii and biceps brachii perform opposing actions and are classified as

antagonists

The __________________________ AND ____________________________major both function in flexing the arm.

coracobrachialis and pectoralis

The extensor digiti minimi muscle extends the _______________________

fifth finger. pinky

The extensor digitorum muscle extends the __________________ and _________________.

fingers , hand

Teres (TEHR-eez) major

is not a muscle of the rotator cuff. The teres major muscle, which originates from the posteroinferior scapula and inserts on the humerus close to the latissimus dorsi tendon, shares similar actions with the latissimus dorsi (adduction, extension, and medial rotation of the humerus).

What muscle elevates the scapula?

levator scapulae

Which of the following bones is not attached to the sternocleidomastoid muscle?

mandible

The ________________________________protrudes the lower lip and chin for drinking and making a "doubtful" expression.

mentalis

Muscles are activated by

motor neurons

Synergist

muscle that aids a prime mover in a movement and helps prevent rotation

The _________________________ closes and protrudes lips (as in pursing the lips).

orbicularis oris

The ____________________________retracts the scapula.

rhomboid major

The _________________pulls the angle of the mouth laterally to make a closed-mouth smile or smirk.

risorius

The_______________________ AND _____________________ both laterally rotate the humerus and stabilize the shoulder joint.

teres minor and infraspinatus

myocin

thick filament

Actin

thin filaments

Supinate

to turn the palm of the hand upward

T tubules

tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the other side

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

steps 1-5, Number the following steps to show the order in which they occur at the neuromuscular junction. Steps 6-10, The next 5 steps of a muscle contraction. Steps 11-15, Cross Bridge Cycling in a muscle cell. steps 11-15

1. Nerve impulse is sent from the brain down the motor neurons to the axon terminal. 2. Calcium enters the axon terminal when the voltage gated channels open from the nerve impulse. 3. Calcium causes the synaptic vesicles to release the neurotransmitter acetylcholine into the synaptic cleft through the process of exocytosis. 4. The calcium ions in the axon terminal are pumped back out into the extracellular fluid. 5. The acetylcholine attaches to receptors on the motor end plate. These chemically-gated receptors open up and allow sodium in and potassium out of the muscle cell. 6. The influx of sodium ions causes an increase in membrane potential (depolarization) of the resting membrane potential. When the membrane electric potential shifts from -70mV to +30mV it is called depolarization of the motor end plate. 7. Depolarization spreads (or propagates) along the sarcolemma and is now referred to as an action potential. Voltage gated sodium channels open and sodium rushes into the muscle cell down the sarcolemma continuing the action potential. 8. The action potential also travels down the T-tubules, marking the beginning of the portion of the process known as excitation-contraction coupling. 9. Once the action potential reaches the terminal cisternae of the sarcoplasmic reticulum, calcium channels in the SR open releasing calcium ions into the sarcoplasm. 10. The released calcium binds to the troponin on the thin filament of the sarcomere, causing a conformational change. 11. The tropomyosin moves out of the way, exposing the myosin binding sites on the actin. 12. The myosin head attaches to the binding sites, forming a cross bridge. 13. The power stroke occurs when the myosin head flexes and pulls the actin toward the center of the sarcomere. 14. To release the cross bridge, ATP attaches to the ATP binding site on the myosin. When ATP binds, myosin detaches from the actin and the ATP is broken down and energizes the myosin head to prepare it for the next contraction (cocking the myosin head) 15. If there is no further stimulation, calcium ions leave the sarcoplasm and return to storage in the terminal cisternae of the SR.

The deltoid and supraspinatus both function in _________________of the arm.

ABDUCTION

Sarcomere

Contractile unit of muscle

latissimus dorsi muscle

Function: Extends and helps adduct upper arm, Insertion: Humerus, Origin: Vertebrae and illium muscle is a powerful agonist of adduction and medial rotation of the arm. The muscle has a broad origin from the iliac crest, the inferior thoracic vertebrae, and all of the lumbar vertebrae, and its fibers converge to a tendon that inserts into the proximal humerus

Myofibrils

Microscopic protein filaments that make up muscle cells.

Which fascicle arrangement has fascicles that attach to the tendon at an angle in such a way that the muscle resembles a feather?

Pennate

The _______________________muscle is a broad, flat, sheetlike muscle found in the superficial neck. It helps produce that open-mouthed, "jaw-dropping" look of horror, and also tightens the skin of the neck.

Platysma