physiology:: Skeletal Muscle Structure & Contraction Flashcards

1
Q

skeletal muscle

  • classification
  • typical location
  • function
A
  • striated voluntary muscle
  • attached to bone of skeleton
  • movement of body in relation to external environment
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2
Q

cardiac muscle
-classification
typical location
function

A
  • striated involuntary muscle
  • wall of heart
  • pumping blood out of heart
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3
Q

smooth muscle
-classification
typical location
function

A
  • unstriated involuntary muscle
  • walls of hallow organs and tubes …eg blood vessels and stomach
  • movement of contents within hallow organs
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4
Q

description of skeletal muscle

  • grouped
  • length
  • thickness
  • shape
  • striated
  • type of cells
A
  • bundles
  • long
  • thick
  • cylindrical
  • striated
  • contractile multinucleate
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5
Q

description of smooth muscle

  • grouped
  • length
  • thickness
  • shape
  • striated
  • type of cells
A
  • interlinked network
  • short
  • slender
  • cylindrical
  • striated
  • contractile cell connected by interculated disk
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6
Q

description of cardiac muscle

  • grouped
  • length
  • thickness
  • shape
  • striated
  • type of cells
A
  • loose network
  • short
  • slender
  • spindle -shaped
  • unstriated
  • contractile cells arranged in sheets
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7
Q

Skeletal Muscle: Structure

what are muscles made up of

A

-group of Fascicles (these contain bundles of muscle fibres)

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8
Q

muscle fibers are surrounded by

A

connective tissue

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9
Q

Layers (of / encompassing) Muscle Tissue

A
sarcolemma
endomysium
perimysium
edimysium
fascia
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10
Q

sarcolemma

A

cell membrane that encloses each muscles cell (muscle fibers)

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11
Q

endomysium

A

connective tissue that wraps each muscle fiber

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12
Q

perimysium

A

connective tissue that wraps bundles of muscle fibres (bundles aka fasciles)

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13
Q

epimysium

A

connective tissue that wraps the whole muscle

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14
Q

fascia or aka deep fascia

A

layer of thickened connective tissue that covers all of muscle

right above epimysium

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15
Q

Skeletal Muscle: Contraction Basics

what do skeletal muscles need in order to contract
how does this work

A

-stimulation by nervous system

-communication at nueromuscular junction…..
impulse travels down nerve and reaches NMJ which causes chemical transmitter to be released causing to trigger muscle contraction

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16
Q

Skeletal muscle is supplied by the

A

efferent arm of somatic nervous system (SNS)

17
Q

Motor neuron activity is

A

cholinergic, nicotinic and only excitatory

18
Q

Muscle Fibre Organisation

A
  • sarcolemma: plasma membrane
  • transverse T tubules :folds of sarcolemma
  • sarcoplasm: cytoplasma (contains many myofibrals)
  • sarcoplasmic recticulum: smooth ER
19
Q

muscle fibre structure

A

regular striated patterns of filaments and organelles hint at functionality

20
Q

Muscle Fibre Organisation

A

muscle fibre composed of myofibrils
myofibrils are repeating units of sarcomeres
sacromeres are regular arrays thick filaments (myosin polymer) and thin filament (actin polymer)

21
Q

Myofibrils give skeletal (and cardiac) muscle

A

striated appearance

22
Q

striations

A

due thin and thick filaments that run parrell to long axis

23
Q

what forms sarcomeres

what are sarcomeres

A

filaments

functional unit…… z line to z line

24
Q

sarcomere dimensions

A

H zone - thick filament (myosin only)
A band- thick filament. and overlapping thin filament(actin)
I band -thin. filament only

25
Q

sarcomere dimensions during contraction

A

H zone decreases in size due to more overlapping in thick and thin filaments

26
Q

Proteins of the Sarcomere

A

contractile - actin and myosin

structural - titin dystrophin

Regulatory- troponin-Complex, tropomysoin