Muscle Tissue Ch 9 Flashcards Preview

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Flashcards in Muscle Tissue Ch 9 Deck (53)
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1

Skeletal Muscles

Organs that attach to and cover the skeleton
Have striations
Voluntary muscle

2

Cardiac Muscle

Only in heart
Striated
Involuntary

3

Smooth Muscle

In walls of hollow, visceral organs.
Nonstriated
Involuntary

4

4 Characteristics of Muscle Tissue

Excitability
Contractility
Extensibility
Elasticity

5

4 Major Muscle Functions

Movement
Posture
Stabilize joints
Generate heat

6

Additional functions of muscle

Protect internal organs
Form valves
Dilate and constrict pupils
Arrector pili in hair follicles

7

Nerve and blood supply

Generally 1 nerve, 1 artery, and 1 or more veins for each muscle.

8

3 Connective tissue sheaths of muscle

Epimysium: Surround whole muscle
Perimysium: Surrounds each fascicle
Endomysium: wispy sheath that surrounds each muscle fiber

9

Attachments

Direct: fleshy attachments, epimysium is attached directly to outside of bone or cartilage.
Indirect: more common, tissue extends beyond muscle as tendon or aponeurosis and anchors to bone or cartilage.

10

Insertion

The attachment at the movable bone

11

Origin

The attachment at the immovable or less movable bone.

12

Sarcolemma

Plasma membrane

13

Sarcoplasm

Cytoplasm of a muscle cell
Contains large amounts of glycosomes (glycogen) and myoglobin (oxygen).

14

Myofibrils

80% of cellular volume
rod-like cylinders that run the length of the cell

15

Sarcomere

smallest, contractile, functional unit of skeletal muscle.

16

Striations

Dark and light bands that wrap around the myofibril.
Dark:A bands
Light: I bands

17

Myofilaments

Smaller structures in sarcomeres: think and thin

18

Thick filaments

Central
Myosin (red)
Length of A band

19

Thin filaments

Lateral
Actin (blue)
Extend across I band into A band

20

Tropomyosin

rob-shaped protein, spiral around the actin core. Stabilize it and block myosin-binding sites.

21

Troponin

Globular-polypeptide complex
TnI: Inhibits, binds to actin
TnT: binds to tropomyosin, positions actin
TnC: binds calcium ions

22

Elastic filiments

Giant protein titin
Extends from Z disc
Forms thick filament core
Holds think in place
Helps muscle spring back

23

Sacroplasmic Reticulum

Interconnecting tubules surround each myofibril. Regulates calcium

24

T Tubules

Transverse, at each A band I band junction
Increase muscle fibers surface area
continuous with extra cellular space
Encircle each sarcomere
Ensures synchronized contraction

25

Terminal Cisterns

"end sacs"
Perpendicular cross channels at A-I band junctions
Involved in energy production

26

Triad Relationship

T tubules, SR and Terminal Cisterns.
T-tubules: act as voltage sensors
SR: gated channels through which terminal cisterns release Ca2+

27

Sliding filament model of contraction

During contraction thin filaments slide past thick so that the actin and myosin filaments overlap to a greater degree.

28

Neuromuscluar junction (NMJ)

or end plate, is a synapse between a muscle cell and neuron. Only one per each muscle fiber, located midway.

29

Acetylcholine

Neurotransmitter released into the synaptic cleft and open NA+ and K+ channels. Triggers action potential.

30

Achetylcholinestrase

enzyme that breaks down ACh and prevents continues muscle fiber contraction.