Chapter 10- Muscles Flashcards Preview

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Flashcards in Chapter 10- Muscles Deck (66)
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1

Myology

scientific study of muscles

2

how much mass do muscles account for

~45%

3

functions of muscles

maintain posture and body position
movement
heat production
guard orifices
support visceral organs

4

properties of muscle tissue

Excitability
-the ability to receive and respond to electrical or chemical stimuli
Contractility
-the ability to shorten forcibly when stimulated
Extensibility
-ability to be stretched without damaging the tissue
Elasticity
-ability to return to original shape after being stretched

5

composition of mucles

-muscles are organs
-consist of many tissue types
-connective tissue
-arteries/veins
-nerves
-lymphatics
-contractile muscle cells

6

skeletal muscle characteristics

-attaches to bone, skin, or fascia
-striated with light and dark bands
-voluntary control
-long, thin and multi-nucleated fibers
-arranged into packages that attach to and cover the bony skeleton
-contracts rapidly, but tire easily
-may exert great force
-fiber=1 muscle cells

7

muscle structure

-belly: main portion of a muscle (thick part)
-belly is attached to tendons
-tendons are attached to bone

8

fascia

-deep fascia
--dense irregular CT around muscle
--holds it in place and separates it form other muscles
-subcutaneous fascia
--loose CT beneath skin, surrounds several muscles

9

skeletal muscle organization

-many muscle fibers are bundled together into groups called fascicles
-10-100 muscle cells
-several fascicles make up a muscle (so several hundred fibers(cells))

10

skeletal muscle CT

-epimysium
-perimysium
-endomysium

11

epimysium

surrounds the whole muscle

12

perimysium

surrounds fascicles

13

endomysium

separates individual muscle fibers

14

tendon formed from what

all connective tissue extended beyond the muscle belly

15

aponeuroses

tendons that form thick flattened sheets

16

myoblasts

embryonic cells that fuse to form muscle fibers
-causes the length and multinucleation

17

myosatellite cells

myoblasts that do not fuse
-assist in repair of damaged cells

18

fiber structure

-sarcoplasm: fiber cytoplasm
-sarcolemma: plasma membrane of a fiber
-transverse (T) tubule: extensions of the sarcolemma into the sarcoplasm

19

myofibrils

contractile organelles
-extend the length of fiber

20

sarcoplasmic reticulum

surrounds the myofibrils
-similar to ER
-contains calcium ions which tell muscle to contract

21

sarcomere

functional unit of the myofibril
-made of thick and thin filaments

22

thick filaments

myosin
-twisted protein with globular heads

23

thin filament

actin
-structural protein
-coiled "beads"
regulatory proteins
-allow/prohibit attachment between actin and myosin
-tropomyosin
-troponin

24

sarcomere bands

cause the striated appearance
bands
-A band: entire thick filament range
-I band: only thin filaments
-H band: only thick filaments
- Zone of overlap: both filaments

25

Sarcomere lines

divide and flank the sarcomere
-Z line:
--end of sarcomere
--made of actin protein
--anchor thin filaments
-M line:
--middle of the sarcomere
--stabilize thick filaments

26

structural proteins

titin: anchors a thick filament to a Z line
-accounts for elasticity and extensibility
nebulin: holds F actin together on thin filaments (runs through center)
actinin: makes up Z line

27

sliding filament theory

actin slides over myosin
-zone of overlap enlarges
-h band shrinks
-I band shrinks
- A band remains the same
- Z line moves closer to A band

28

Neuromuscular junction is made up of

-motor unit
-neuromuscular junction
-synaptic termical
-motor end plate
-synaptic cleft
-neurotransmitter

29

motor unit

neuron and all the muscle cells stimulated by the neuron

30

neuromuscular junction

point of contact between the neuron and the muscle