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Flashcards in Topic 7 Deck (35)
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1

Skeletal mm is formed from a fusion of hundreds of embryonic cells called _________?

Myoblasts

2

Plasma membrane of skeletal mm is called the __________?

Sarcolemma

3

The cytoplasm of skeletal mm cell is ka _________ and it contains structures that allow the cell to generate the ____ needed for contraction.

Sarcoplasm
ATP

4

Structures found in sarcoplasm

Glycogen (glucose polymer)
Mitochondria
Myoglobin (O2 storing protein)

The majority of the sarcoplasm contain myofibrils - rod like cylinders.

5

Each myofibril is composed of __________ and consist of a repeating orderly arrangement of units ka sarcomeres.

What are the proteins they are made from?

Myofilaments
Made from the proteins actin and myosin

6

Is referred to as the thick filament

Myosin

7

Is referred to as the thin filament

Actin

8

The _______ consist of the following pattern; a region of just thin filaments followed by region of thin and thick filaments that overlap

Myofibril

9

This region of thin filament appears light and is referred to as the ___ band

I band

10

This region of overlap appears dark and is referred to as the ____ band

A band

11

The dark A band has a small lighter area in the midsection known as the ___ zone which is vertically bisected by the dark line called the ___ line

H zone
M line

12

The ___ zone contains thick filament only and has no overlap

H zone

13

Each I band is also bisected vertically by a dark line known as the _________

Z disk

14

The basic functional unit of the muscle cell.
___________ is a defined segment of a myofibril.

Sarcomere

15

The linkage between actin and myosin is known as

A cross bridge

16

During the act of muscle contraction, what gets smaller?

The muscle fiber, the myofibrils within the muscle fiber, sarcomeres, distance between the Z discs, I band, H zone

Note: that the A band move closer together but they do not decrease in size

17

What tissue types are found in skeletal muscle?

Skeletal muscle tissue, nervous tissue, epithelial tissue, and connective tissue

18

What tissue surrounds the skeletal muscle? (Epimysium)

Dense irregular CT

19

Within the muscle there are bundles of skeletal muscle fibers known as _________.

Fascicles

20

Each fascicle is surrounded by layer of fibrous CT ka _________

Perimysium

21

What is comprised of the endomysium?

A loose sheath of CT

22

The attachment of a skeletal mm to a bone is usually classified as an ________ (the bone that does not move) or an _______ (the bone that moves)

Origin and insertion

23

The arrival of an action potential at the axon terminal will promote the release of ______________ into the synaptic cleft

Acetylcholine (ACh)

24

ACh Will diffuse across the synaptic cleft and bind to the __________ _________ on the motor and plate

Cholinergic receptors

25

These cholinergic receptors are chemical gated ion channels. The binding of acetylcholine causes these channels to open. This results in the influx of ________ and membrane depolarization known as a graded potential. If it is strong enough it will cause an action potential.

Na+ (sodium)

26

The stimulation of the motor endplate by the acetylcholine is short live it since the synaptic cleft contains the enzyme _________________________ which quickly breaks down acetylcholine.

Acetylcholinesterase

27

The endoplasmic reticulum of the muscle cell is known as

The sarcoplasmic reticulum

28

The action potential will spread down the membrane of the

T tubules

29

The rise in sacroplasmic _______ levels will begin the process of contraction

Ca2+ (calcium)

30

Under resting conditions, myosin cannot latch onto actin and form cross bridges because the myosin-binding sites on actin are blocked by a protein called

Tropomyosin