Muscle Tissue Flashcards Preview

Cell Biology Exam 2 > Muscle Tissue > Flashcards

Flashcards in Muscle Tissue Deck (40):
1

3 types of muscle

skeletal, cardiac, and smooth

2

Sarcomere

contractile unit of striated muscle. Expands from one Z disc to the next Z disc

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G-actin

globular actin monomer. assembles to form a polymer that kinda looks like a string of beads

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Filamentous actin

two polymers twisted together

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Thin filaments

made up of actin and troponin

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Tnt

attaches to tropomyosin

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TnC

binds calcium ions during muscle contraction

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TnI

attaches to actin monomer to block actin/myosin interation

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Tropomyosin

consists of two polypeptide chains that come together to form an alpha helix.

10

Myofibril

sacromeres attached to one another to form a large cylindrical series

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Vesiculus

msucel fibers come together to form these

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A-band

Dark band. contains thick and thin filaments. bisected by H band

13

I band

contains only thin filaments
bisected by Z disc

14

H band

contains only thick filaments

15

Sarcomere accessory proteins

attach, space, and align myofilaments for an even, prcise and orderly arrangment. HOld think and thick filaments in place

16

Nebulin

nonelastic protein. 2 molecules hold thin filament in place

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Titin

elastic protein. HOlds thick filament in place. Acts like an ianchor

18

Myomesin and c prtein

hold thick filaments in place

19

Endomysium (reticular fibers)

delicate layer of connective tissue. surrounds each muscle cell/fiber

20

Perimysium Icollagenous CT)

surround each bunch/bundle of muscle cells

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Epimysium (collagenous CT, deep fascia)

surrounds many bundels

22

Skeletal muscle

voluntary control.

23

T-tubules

run peripendicular to longitudinal acis of cell. Open into extraceullular space. Lumen is continuous.

24

Triad - at A-I of sarcomere

two terminal cisternae with a T-tubule. Contain calcium in lumen for muscle contraction

25

Axon terminal branches

nerve branch has dilated structure closely attached to skeletal muscle cells/fibers

26

Myoneural junction

point of contact between terminal and cell

27

Presynaptic terminal

contains synaptic vesciles.

28

Moto unit

nerve cell and all the muscle fibers it innervates

29

Myasthenia Gravis

autoimmune disease. Autoantibodies inferfere with muscle contraction. Specifically fucks with actylcholine

30

Duchenne Muscular Dystrophy

affect striated muscle. Most common and most severe form.

31

Purkinje Gibers

specialized cardiac muscle fibers. Relay electrical impulses to regular cardiac muscles to cause contractino. Located in endocardium

32

Smooth muscle

No sacromere. No alternating light and dark bands. Cells packed very tightly, without extracellular space. Has euchromatic nucleus located in wider part of cell

33

Smooth muscle cells

Has caveolae on interior surface of cell membrane to release Ca++ into cell fo rtraction. Pinocytotic vesciles located all along inner surface of smooth muscle membrane.

34

Dense bodies

found in smooth muscle cells. Can either be anchored to inner surface of cell membrane or locacted at point of contact of myofilament bundles imbedded within the cytoplasm.

35

What happens to nucleus when smooth muscle contracts

It curls

36

How does nerve impulse spread in skeletal muscle

Sweep oer entire sarcolemma, comes to openings of T-tubules along sacrolemma surface. Spread deep into muscle. Changes permeability of sarcoplasmic reticulum

37

Myofibrils

found in cytoplasm. Made of sarcomeres

38

How is Ca++ released

by terminal cisternae on myofibril surface

39

What does Ca++ do

binds to TC subunit, changes confirmation of troponin. TnT bound to tropomyosin pushes tropmyosin filament deeper into groove on actin filament. Myosin biding site of actin monomer on the actin filament is exposed. This whole process requires ATP

40

What happens during muscle contraction

-Thick filaments pull on thin filaments and slide over them
-Globular heads attach to thin filament actin sites and drag them to midline
-Z-discs get closer to each other and closer to midline
-The length of the thick and thin filaments stay the same.