Chapter 9 Flashcards by Kaelin Alumbaugh

What are the three types of muscles?

Skeletal
Smooth
Cardiac

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Is skeletal muscle tissue striated?

Yes

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Skeletal muscle tissue contractions

Are rapid, and in return it tires easily

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Explain blood supply to skeletal muscle tissue

Arteries deliver oxygen and nutrients, veins take waste away

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Is smooth muscle tissue striated?

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Is cardiac muscle tissue striated?

Yes

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Sarcolemma is the

Plasma membrane

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Sarcoplasm is the

Cytoplasm of the muscle cell

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Excitability/Irritability is

The ability to receive and respond to stimuli

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Contractibility is

The ability to shorten

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Extensibility is

The ability to be extended or stretched

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Muscles maintain

Posture
Stabilize joints
Generate heat

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Organization of a skeletal muscle

Muscle
Fascicle
Muscle fiber
Myofibril
Sarcomere
Myofilament

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Fascicles are a portion of

The muscle

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Muscle fibers are also known as

Muscle cells

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Myofibrils are complex

Organelle

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Myofibrils have a ________ structure

Rod-like

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Myofibrils occupy most of the

Muscle cell volume

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What are myofibrils composed of?

Sarcomeres arranged end to end

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Are myofibrils striated?

Yes

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What make up the striations of myofibrils?

A bands and I bands

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Sarcomere is a segment of

A myofibril

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What is the smallest contractile unit?

The sarcomere

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Sarcomere are composed of

Myofilaments

Where are sarcomeres found?

Between two Z-discs

What are the two contractile myofilaments?

Myosin and Actin

Myosin is what kind of filament?

Thick filament

Actin is what kind of filament?

Thin filament

What kind of structure does myosin have?

A head and a tail

Myosin tails are

Two interwoven polypeptide heavy chains

Myosin heads are

Two light/smaller polypeptide chains

Within actin, what two proteins play a part?

Tropomyosin and Troponin

Tropomyosin and Troponin are

Regulatory subunits that are bound to actin and play a role in contractions

How are myosin and actin involved contractions?

They slide past one another which causes shortening and contraction

What are the three connective tissue sheaths?

Epimysium Perimysium Endomysium

Sarcoplasmic reticulum functions in

The regulation of intracellular calcium levels

T tubules conduct

Impulses to the deepest region of muscle

The impulse from the t tubules signals

The release of calcium

Myosin extend the entire length of

The A band

Actin extend across

The I band

Z discs do what?

Anchor thin filaments

Where do thin filaments not overlap thick filaments?

In the H zone

The M line connects

Thick filaments

Sliding filament model of contraction (7)

(1) In a relaxed state,myosin and actin only overlap a little bit (2) Upon stimulation, one myosin head will bind to actin and sliding begins (3) Calcium binds to troponin (4) Troponin changes shape (5) When troponin changes shape, tropomyosin moves and uncovers head sites (6) Myosin heads bind to actin (7) ATP binds to the head and the head releases

The neuromuscular junction is made up of

Axonal endings

Axonal endings contain

Acetyl Choline (ACh)

Acetyl Choline is a

Neurotransmitter

What holds in ACh?

Axonal vesicles

The synaptic cleft is the

Space between the neuron and muscle tissue

Muscle Contraction (7)

(1) Nerve impulse travels to axon terminal (2) Causes voltage gated calcium channels to open (3) Influx of calcium (4) Calcium causes sacs with ACh to fuse to the membrane (5) Causes the release of ACh into the synaptic cleft (6) ACh binds to ACh receptors on the sarcolemma (7) ACh binding initiates an action potential

Breaking down steps 6 and 7 of the muscle contraction (7)

(1) Sarcolemma becomes permeable to Na and K (2) Causes change in polarity; Inside of the cell becomes more negative (depolarization) (3) Depolarization causes the action potential to travel down t tubules (4) Causes release of calcium (5) One calcium is released, it binds to troponin, which causes tropomyosin to move (6) Allows myosin heads to bind to actin (7) Allows contraction

What destroys ACh?

Enzyme acetyl cholinesterase (ACh enzyme)

Where is ACh destroyed?

Within the synaptic cleft

The deconstruction of ACh does what?

Prevents continued contractions

What would happen in a lack of ACh enzymes?

Contractions would be able to be stopped

would would happen with a lack of ACh receptors?

It would be hard to contract or possibly no contraction at all

Myasthenia Gravis is caused by

A lack of ACh receptors

What are symptoms of Myasthenia Gravis?

Weak muscles, weak vision, drooping eyelids, hard to speak or swallow