lab exam 3

what is a sarcomere

the fundamental repeating unit of a muscle causing the contraction

what are the parts of a sarcomere

what are the component parts of a muscle fiber

the myofilaments actin and myosin along with the dark a band and the light i band making up the sarcomeres and the transverse tubules and sarcoplasmic reticulum

what is occurring at a neuromuscular junction

the space between the nerve and the muscle and is responsible for transmission of electrical impulse from a nerve to the muscle

what are the parts of a neuromuscular junction

what are the three phases of a muscle twitch

lag phase, contraction phase, relaxation phase

what is the lag phase

the time when the electrical impulse travels across the muscle cell membrane and calcium ions are released from the sarcoplasmic reticulum

what is the contraction phase

the myofilaments slide across one another and the muscle fiber shortens causing a contraction

what is the relaxation phase

the phase in which the fiber returns to a resting state

what are the parts of the sliding filament model

what types of filaments are present at the a band

actin (thin) and myosin (thick) filaments

what types of filaments are present at the i band

actin (thin) filaments

what types of filaments are present at the h zone

myosin (thick) filaments

what happens at the neuron axon during a skeletal contraction

the action potential reaches the end of the axon and acetylcholine is released

what happens when a neurotransmitter binds to receptors on the muscle cell membrane

channels are opened and sodium ions enter the cell

how is action potential delivered to the interior of a muscle cell

the t tubules carry the action potential into the interior of a cell

what ion is released in skeletal muscle contraction

calcium

what is a motor unit

a motor neuron and all the muscle fibers innervating it

what are the parts of a motor unit

what is a graded response

the amount of action potentials necessary for a muscle contraction

what is temporal summation

changing the frequency of simulation

what is multiple unit summation or recruitment

changing the strength of a stimulation

what is fused tetanus

no relaxation between contractions

what is unfused tetanus

the muscle fibers do not completely relax

what is an all or nothing response

the muscle fiber either contracts or it doesn’t

epimysium

dense irregular elastic tissue covering the entire muscle

perimysium

dense irregular elastic tissue covering muscle fascicles

endomysium

areolar connective tissue covering the individual muscle fibers

what are the structures of a skeletal muscle fiber

origin

the stationary part of a muscle end

insertion

the more mobile part of a muscle end

muscle function or action

the effects the muscle has on a part of the body

innervation

the name of the nerve that controls the muscle

what are the 8 criteria used to name muscles

shape, location, size, orientation, origin and insertion, number of heads, action and length

what is an example of a muscle named for its location

the tibialis or the frontalis

what is an example of a muscle named for its size

the adductor magnus or gluteus minimus

what is an example of a muscle named for its shape

the deltoid

what is an example of a muscle named for its orientation

the transversus

what is an example of a muscle named for its origin and insertion

the infraspinatus or hallucis

what is an example of a muscle named for its number of heads

the triceps or biceps

what is an example of a muscle named for its action

the extensor

what is an example of a muscle named for its length

the longus or brevis

what are the four muscles of the rotator cuff

subscapularis, infraspinatus, teres minor and supraspinatus

what are the four muscles that make up the quadriceps femoris group

vastus medialis, vastus lateralis, rectus femoris and vastus intermedius

what three muscles make up the hamstring group

biceps femoris, semitendinosus, semimembranous

what three muscles make up the achilles

gastrocnemius, soleus, and the plantaris

what is a a function of the deltoid

arm abduction (raising over ones head)

what is a function of the triceps brachii

extension of the elbow joint

what is a function of the subscapularis

internal rotation of the head of the humerus

what is a function of the infraspinatus

provides glenohumeral stability

what is a function of the biceps brachii

flexion and supination of the forearm

what is a function of the pectoralis major

adduction of the arm

what is a function of the supraspinatus

stabilizes the humerus head on the glenoid fossa

what is a function of the teres major

extend, adduct, and internally rotate the humerus

what is a function of the brachialis

provides flexion of the elbow

what is a function of the supinator

to supinate the forearm

what is a function of the pronator teres

pronates the forearm

what is a function of the latissimus dorsi

adduct and extend the arm at the glenohumeral joint

what is a function of the brachioradialis

flexes the forearm at the elbow

what is a function of the flexor retinaculum

serves as a pulley for the carpal flexor muscles

what is a function of the teres minor

stabilizes the glenohumeral joint by helping hold the humeral head

what is a function of the trapezius

helps to stabilize and move the scapula

what is a function of the tensor faciae latae

assist in movement and stabilization of the hip and knee

what is the function of the vastus medialis

extends the knee and assists in stabilization of the patella

what is the function of the biceps femoris

thigh extension, knee flexion and external rotation

what is the function of the adductor magnus

flexes and extends the thigh

what is the function of the pectineus

flexes and adducts the thigh at the hip joint

what is the function of the gracilis

assists in hip adduction and knee flexion

what is a function of the vastus lateralis

extend the knee

what is a function of the tibialis anterior

dorsiflexion

what is the function of the semimembranous

knee flexion and internal rotation

what is the function of the illiotibial tract

overall important structure involved in lower extremity motion

what is the function of the extensor retinaculum

connect the tibia and the fibula

what is the function of the sartorius

helps in rotating the thigh laterally

what is the function of the rectus femoris

extend the knee

what is the function of the extensor digitorum longus

to extend the lateral four tarsals

what is the function of the gluteus medius

assist in flexion and medial rotation of the hip

what is the function of the achilles (calcaneal) tendon

causes plantar flexion of the foot allowing in locomotion

what is the function of the gastrocnemius

helps in walking and posture

what is the function of the vastus intermedius

knee extension

what is the function of the semitendinosus

extend at the hip and flex at the knee

what is the function of the gluteus maximus

extend the hip

what is the function of the adductor longus

adduct the thigh at the hip joint

what is the function of the soleus

provide plantar flexion and posture

what is the function of the linea alba

to maintain the abdominal muscles at a certain proximity to each other

what is the function of the transverse abdominus

to maintain abdominal tension and support abdominal viscera

what is the function of the rectus abdominis

to move the body between the ribcage and the pelvis

what is the function of the diaphragm

to assist in breathing

what is the function of the external abdominal oblique

to help rotate the trunk

what is the function of the internal abdominal oblique

movement of the trunk

what is the function of the serratus anterior

to lift the rib cage and assist in breathing

what is the function of the sternocleidomastoid

rotation of the head

what is the function of the occipitofrontalis

to move the scalp forwards

what is the function of the orbicularis oris

allows in movement of the lips

what is the function of the orbicularis oculi

closes the eyelids

what is the function of the sternohyoid

depresses the hyoid bone during speech and swallowing

what is the function of the temporalis

to produce movements of the mandible

what is the function of the buccinator

to assist in swallowing, sucking, etc.

what is the function of the digastric

swallowing, chewing, and speech

what is the function of the masseter

responsible for chewing