MODULE 5 - THE MUSCULAR SYSTEM: HISTOLOGY AND PHYSIOLOGY

The muscle system provides/enables what three things?

Movement, Posture, and heat production

Skeletal muscles are

striated and voluntary

Cardiac muscles are

striated and involuntary

Smooth muscles are

non-striated, involuntary

The three ends of muscles are

smooth, cardiac, and skeletal muscles.

what are the four major functional characteristics of muscle tissue?

Contractibility, excitability, extensibility, and elasticity

the belly of the muscle is composed of...

actual muscle cells

the whole muscle is divided into bundles called _______________

fascicles

You need to think Muscle fiber =

Muscle cell

Each muscle cell is rapped in ____________________ and each fascicles are wrapped in __________________ (aka _____________)

perimysium, epimysium, fascia

The skeletal muscle fibers are multinucleate. The nuclei are located under the _________________, which is the ______________ of the muscle fibers

sarcolemma, plasma membrane

the ____________________ ____________________ is just the endoplasmic reticulum of a muscle fiber

sarcoplasmic reticulum

The sarcolemma has tiny tubes called

T-tubules

sarcoplasmic reticulum surround regions that are packed with _____________

myofibrils

each basic unit of a myofibrils contain two types of filament called

actin myofilaments and myosin myofilaments

Sarcomere

The repeating unit of a myofibril

In the attached image, you see a protein called ______________, which forms ________________ Myofilament. The thinner Myofilament is made up of the protein called __________

Myosin, Myosin, actin

Actin myofilaments contain two other proteins besides actin:

troponin, and tropomyosin

Neuron

The functional unit of the nervous system, a nerve cell

Synapse

the interface between a neuron and another cell

neuromuscular junction

The result of the axon of a motor neuron reaching the perimysium surrounding several muscle fibers. and its branches connect with the muscle fiber.

synaptic cleft

The narrow gap that is between the end of the axon and the muscle fibers

presynaptic terminal

end of nerve cell (axon)

The membrane of the muscle fibers in the synaptic cleft are called

Postsnyaptic terminal

The snyaptic vesicles of neurons that stimulate muscle fibers hold an important chemical called

acetylcholine (ACh)

Neurotransmitters

a chemical released by a neuron, which diffuses across the synaptic cleft, enabling the neuron to communicate with another cell.

Rigor mortis occurs because ________.

no ATP is available to release attached actin and myosin molecules

antagonist muscle

a muscle which performs the opposite action of the muscle in question

motor unit

one motor neuron and all the muscle fibers it innervates

all-or-nothing law of skeletal muscle contraction

An individual muscle fiber contracts maximally in response to an action potential

subthreshold stimulus

a stimulus too small to create an action potential in a neuron

threshold stimulus

a stimulus strong enough to create one action potential in a neuron

submaximal stimuli

Stimuli of increasing strength that create more action potentials along more neurons

maximal stimulus

A stimulus that is strong enough to create action potentials on all motor neurons to a particular muscle

supramaximal stimulus

any stimulus stronger than a maximal stimulus. These stimuli cannot produce a greater frequency of action potentials than a maximal stimulus.

when the muscle fibers in the the motor unit contract, we say that the motor unit has been _________________

recruited

multiple motor unit summation is when...

...many motor units are recruited causing the whole muscle to contract with great force

muscle tone

the state of partial contraction in a muscle even when the muscle isn't being used.

three was the muscle fiber produces ATP:

Aerobic respiration, creatine phosphate, and anaerobic respiration

Creatine phosphate + ADP =

creatine + ATP

The two main reason you pay back oxygen debt

(1) you need to replace the ATP and creatine phosphate used while exercising (2) You need to remove the lactic acid from the muscle fiber.