ch 10 connect AP 150

label the figure to illustrate your understanding of muscle attachements

(look at connect print out, pg 4) origin relaxed muscle insertion contacted muscle

label the structures of a skeletal muscle fiber

(look at connect print out, pg 5) sacrolemma myofibril sarcoplamic reticulum nucleus myofilament

label the structures of sacromere

(look at pg 6 of connect print out) m line i band a band z disc

based on your understanding of the process of skeletal muscle contraction, indicate whether each figure represents a relaxed, partially contracted, or fully contracted skeletal muscle

(look at pg 6 of connect print out) partially contracted fully contracted relaxed

label the connective tissue in the figure

(look at the connect ) deep fascia perimysium epimysium endomysium

label the components of skeletal muscle

(look at the connect print out pg 2) skeletal muscle fascicle muscle fiber myofibril

place the events involved in muscle contraction in the correct order

-a nerve impulse causes ACh release at a neuromuscular junction -ACh binds receptors on the motor end plate, initiating a muscle impulse -calcium ions bind to troponin, causing tropomyosin to move and expose active sites -myosin heads attach to actin and form crossbridges -a cyclic "attach, pivot, detach, return" event occurs -calcium ions are moved back into the sarcoplasmuc reticulum by ATP-driven pumps -myofilaments passively return to their original state

true statements regarding cardiac and smooth muscle

-cardiac muscle cells can generate a muscle impulse without nervous stimulation -smooth muscle contraction is fast and fatigues easily -smooth muscle is not striated

Arrange the following in the proper order in which they occur at the post-synaptic side of a neuromuscular junction. 1. Action potential is propagated over the muscle cell membrane 2. Depolarization of the post-synaptic membrane 3. Sodium ions move into muscle cell

3. Sodium ions move into muscle cell 2. Depolarization of the post-synaptic membrane 1. Action potential is propagated over the muscle cell membrane

Muscle contraction is dependent upon proper nervous system stimulation. The region where the neurological signal is transferred to the muscle is called the neuromuscular junction.

A motor unit consists of a single motor neuron and all of the muscle fibers it innervates. The production of an action potential by the motor neuron results in the release of the neurotransmitter acetylcholine. Acetylcholine diffuses across the fluid-filled synaptic cleft and binds to receptors present on the motor end- plate of the muscle fiber. The resulting excitation of the muscle fiber is the first step in eliciting muscle contraction.

Myosin heads directly use ______________ to transition to their _____________________ conformation, which enables them ready to bind to actin.

ATP; energized

The ability of a muscle cell to lengthen in response to antagonistic muscles contracting is referred to as

Extensibility

The excitation of a muscle fiber occurs when there is sufficient depolarization at the motor end-plate to produce an action potential. This electrical signal propagates along the sarcolemma and into the muscle fiber by way of the transverse tubules (T-tubules). At the triad, the electrical signal gets converted to a mechanical signal when calcium is released from channels found at the terminal cisternae of the sarcoplasmic reticulum.

LOOK AT CONNECT TO SEE THE CORRECT ANSWER

The primary neurotransmitter at the neuromuscular junction is

acetylcholine.

proteins of thin filaments

actin- a protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells titin-(also known as connectin, is a protein that, in humans, is encoded by the TTN gene. Titin is a giant protein, greater than 1 UM in length, that functions as a molecular spring which is responsible for the pasive elasticity of muscle)

Stand on both feet and bring one foot up to touch the heal of your foot to your buttocks. The hamstring muscles are acting as what?

agonist

The brachialis muscle is the prime mover of elbow flexion, while biceps brachii assists. In other words, during elbow flexion brachialis is the ______ and biceps brachii serves as the ________.

agonist; synergist

After wearing a cast on your wrist for several weeks, you notice that your forearm muscles appear smaller and are weaker than before. This wasting of muscle tissue is termed muscle ______________.

atrophy

what are the function of skeletal muscle tissue

body movement maintenance of posture temperature regulation storage and movement of material support

striated, autorhythmic

cardiac

active generation of force

contraction

ability to return to original length

elasticity

surrounds each muscle fiber

endomysium

surrounds the whole skeletal muscle

epimysium

ability to respond to stimuli

excitabilty

ability to extend in length

extensibility

each muscle fiber may contract completely, partially, or not at all, depending on the strength of the stimulus

false

in the limbs, the insertion of a muscle typically lies proximal (closer to the trunk) to its origin.

false

in the gulteus maximus, each motor unit controls a(n) _____amount of muscle fibers than a motor in the eye muscles

greater

Your school wins the homecoming football game against its biggest rival. You watch as the smallest cheerleader tries to lift up the heaviest linebacker in her excitement. As she strains against his 300 lb. load and does not move him, what type of muscle contraction are her muscles experiencing?

isometric

the specialized region of the sacrolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the

motor end plate

place the organizational level of muscle tissue in order, beginning with muscle and ending with the smallest component

muscle fascicle muscle fiber myofibril myofilament

a motor neuron transmits the effect of a nreve impilse to the muscle fiber at a _____ ______

neruromuscular juntion

Acetylcholine causes an end-plate potential by triggering the ______________________.

opening of sodium channels

surrounds the fascicles

perimysium

striated, multi nuclei

skeletal

unstriated, single nucleus

smooth

Acetylcholine (ACh) is released from motor neurons and enters the __________________.

synaptic cleft

at the ends of the muscles, the connective tissues merge to form a ____, which attaches the muscle to other structures

tendon

the component of a muscle fiber that quickly transports a muscle impulse from the sacrolemma throughout the entire muscle fiber is called the

transverse tubule (t-tubule)

The area between the pre-synaptic nerve cell and the post-synaptic muscle cell is termed the synaptic cleft.

true

Thin filaments connect to and extend from either side of a ___________. These thin filaments are composed largely of the myofilament ____________.

z disc; actin