Ch 11 Flashcards by Nelson Toggy

Excitability

A muscular tissue’s ability to generate Action Potential

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Contractility

A skeletal muscle’s ability to shorten

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Extensibilty

A muscle tissues ability to stretch

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Elasticity

A skeletal muscle tissue’s ability to get back to original length

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Muscle Cell germ layer

Mesoderm

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¿¿¿Muscle Cells are Multinucleated

1)Because muscle cells are very large and contain a fusion of many myocytes that produce/form myotube
2)Myotubes enable cells to produce proteins that fill the center of myofiber

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Myofiber

Part of a muscle cell that produces contraction

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3 PRIM Muscle Tissue Types

Skeletal Muscle
Cardiac Muscle
Smooth Muscle Tissue

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Skeletal M (MA&F)

-Cylindrical
-Multinucleated
-Long
-Striated
Voluntary Control

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Cardiac M (MA&F)

Branched
Single Nuclues
Striated
Intercalated discs
Autonomic Control

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Smooth M (MA&F)

Smooth
Tapered
No striations
Single Nucleus
Autonomic Control
Ex. Digestive Tract

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Epimysium

Outside Connective tissue cover around whole muscle

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Perimysium

Covering that gathers around group of muscle fibers/Fasicle

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Endo-Mysium

Deepest Covering that gathers around individual muscle cell

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Origination Place of Tendon

They come from the coming together of epi, peri, and endo-mysiums

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Aponeurosis- (ex)Latissimus Dorsi, abdominal aponeurosis

Aggregate of Endo/Peri/Epi mysium
-Flat Tendon that allows muscles to be attached to bones that won’t move so that when the muscle contracts it enables for other things to move

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Fascia

collagen rich Connective Tissue covering found around (MUSCLE GROUP)

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Sacrolemma

Membrane of muscle cell

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Alpha motor neurons

Neurons that stimulate Skeletal Muscle cell

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Regulatory Proteins of Muscle

(Control when Muscles are going to contract)

Contractile Proteins (2)

MYOSIN Protein-

ACTIN Protein

Structural Proteins

Maintain structure of myocyte

Myosin

-“Thick Filament”= Larger/Thicker

-Contains tail region that consists of 2 proteins that wrap around each other
-(Hinge Region/ “kneck region”) tension producing segment that sits between Tail region and globular heads
- Myosin protein ends have 2 globular heads
-Arranged in spiral around muscle fiber

Myosin Hinge region

-When hinge region changes its shape it pulls on actin protein and tension is produced between both proteins.

Myosin Globular head

-Contains actin binding site at the the tip of head -Contains enzymatic region where binding of ATP takes place and then carry out a hydrolic reaction so that phosphate bond is broken and allows for a release of chemical energy that uses in part to change hinge region shape and produces tension.

Actin Protein (3 components)

G- actin- individual monomer protein (Globular)- Actin protein F- Actin- Globular shaped actin Proteins bound together to form Filament(Filamentous Actin) Myosin Binding Site- Found at each individual actin Protein. Tropomyosin blocks binding of Myosin and Actin

Troponin (RGP) regulatory proteins

RGP that binds calcium (Ca2+ binding site)

Tropomyosin (RGP)

long protein that covers myosin binding site (on Actin) when muscle contraction is unwanted

Aplha-Motorneuron

Innervate/connect to skeletal muscle cells

Motor End Plate

Section of Sacrolemma where where axon terminal synapses

Cause of formation of a Crossbridge

Binding of Actin and Myosin head

Maximal Tension at sarcomere

Length- 2.0-2.3 microns

Why is Tension Maximal @ sarcomere length of 2.2 microns?

(2.0-2.3 microns) signifies that maximal crossbridges are formed between Myosin and Actin

Latent Period in Muscle Contraction

Skeletal muscle tissues need time dispel of slack within itself

Voltage gated channel

Opened by depolarization

Motor Unit

The alpha motor neuron and each of the individual muscle fibers/cells that it innervates

4 major phases of Muscle Contraction

1. Excitation 2. Excitation-Contraction coupling (ACh to Muscle AP) 3. Contraction 4. Relaxation

Muscular Fatigue

Decrease in muscular force production overtime -Main factors: Release of H+ that drops ph inside muscle cells : ADP and Pi concentration increase which causes ATP hydrolysis : (K+ efflux) Exit of Potassium from muscle cell : Central Fatigue

Wave Summation/Incomplete Tetanus/Temporal Summation

Upward increase in tension as a result of repeated stimuli, calcium isn’t given enough time to return back to SR

Fused Tetanus

Frequency of Stimuli is applied so rapidly that all troponin available binds calcium and maximal number of crossbridges are formed Horizontal line that is formed after Max tension is produced

Twitch

Stimuli is applied, cross-bridges are formed, and calcium is put away back in the SR (sarcoplasmic Reticulum) due to slow frequency of stimuli

Isometric Contraction

No movement is being produced, muscle is being contracted but does not shorten

CONCENTRIC iso contraction

Muscle shortens, (flexing of muscle against gravity) (tension is present)

Eccentric iso contraction

Extension of muscle( muscle is elongated as crossbridges are being formed)

(Slow Oxidative)-SO Fiber / Type l

Most Fatigue Resistant fiber, smallest of the 3, slowest contraction, Oxygen Capacity- High Force production- weak

Fast Oxidative FO(-type lla)

Contraction time- moderate/fast Oxygen Capacity- High Size- medium Fatigue Resistance- moderate Force Production- moderate

Fast Glycolytic

Contraction- very fast Oxygen Capacity- very low Size- largest Fatigue resistance- least/little Force Production- Very High

Fiber types are never mixed in a motor unit

Question 25