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Flashcards in Chapter 10 Deck (91)
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1

The three types of cells in muscle tissue are

1. skeletal
2. cardiac
3. smooth

2

What function do all three muscle tissue types share in common?

generate muscle tension

3

What are some other functions of muscle tissue?

creates movement, maintains posture, stabilizes joints, generates heat, and regulates the flow of materials through hollow organs.

4

What do skeletal muscle cells and cardiac muscle cells have in common?

they are both striated

5

What makes smooth muscle different from skeletal and cardiac muscle tissues?

no striations

6

Define contractility

the ability of proteins within a cell to draw together. Contraction does not mean shorten

7

Define excitability.

muscle cells are responsive to stimuli

8

Define conductivity.


when a muscle cell is excited, the electrical changes rapidly conduct along the entire length of the plasma membrane

9

Define extensibility

stretching of muscle cells up to 3 x's their length

10

Define elasticity

the ability for cells to return to their original shape after stretching

11

What are myocytes? What is the sarcoplasm? What is the sarcolemma?

muscle cells. sarcoplasm is a myocytes cytoplasm. sarcolemma is the myocytes plasma membrane (phospholipid bylayer)

12

What does the sarcoplasmic reticulum store and release?

calcium

13

which is the most abundant organelle of skeletal muscle cells, and is made up of contractile proteins?

myofibrils

14

What surrounds the myofibrils and stores and releases calcium ions?

sarcoplasmic reticulum

15

Transverse tubules (T-tubules) are deep inward extensions of............. that are filled with extracellular fluid.

sarcolemma

16

Terminal cisternae are enlarged sections of ............. found flanking each T- tubule. Two terminal cisternae and their corresponding T-tubule form a ................

sarcoplasmic reticulum. Triad

17

What are the 3 types of myofilaments?

thick, thin, and elastic

18

Thick filaments are composed of bundles of............

many molecules of the contractile protein, myosin

19

What 3 proteins are thin filaments composed of?

actin, tropomyosin, troponin

20

Tropomyosin is a long rope-like regulatory protein that twists around ............ , covering up its active sites.

the 2 actin strands so it covers up the active sites, while at rest.

21

Troponin is a small globular regulatory protein that holds ............. in place and assists with turning contractions on and off.

tropomyosin

22

Elastic filaments are composed of a single massive, spring-like structural protein called ............ that stabilizes the myofibril structure and resists excessive stretching force.

titin

23

Striations appear microscopically as alternating light, or I, bands, where only ............. filaments are found and dark, or A, bands, where both
............... and .............. filaments are found.

thin, thick and thin

24

In the middle of the A band where only thick filaments exist is the........... The ............. line is a dark line in the middle of the A band made up of structural proteins. The ......... disc is found in the middle of the I band and is composed of structural proteins.

H zone. M line. Z disc

25

what is a sarcomere? A sarcomere extends from one .............. to the next.

z disc. It is the functional unit where contraction occurs.

26

During a contraction, both the ............. and the ........... narrow while the A band remains unchanged.

I bands and the H zone

27

Myosin heads attach to actin to pull the thin filaments towards the M line, which brings ............... closer together, shortening the sarcomere.

z discs

28

What are membrane potentials due to?

an unequal distribution of ions near the plasma membrane resulting in a polarized resting state.

29

What is the resting membrane potential? How many milivolts does it measure?

the electrical potential across the sarcolemma of a resting muscle fiber. 70 millivolts

30

when does resting membrane potential change?

when the barrier to ion movement is removed from the plasma membrane.