Ch 11 Flashcards
Excitability
A muscular tissue’s ability to generate Action Potential
Contractility
A skeletal muscle’s ability to shorten
Extensibilty
A muscle tissues ability to stretch
Elasticity
A skeletal muscle tissue’s ability to get back to original length
Muscle Cell germ layer
Mesoderm
¿¿¿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
Myofiber
Part of a muscle cell that produces contraction
3 PRIM Muscle Tissue Types
Skeletal Muscle
Cardiac Muscle
Smooth Muscle Tissue
Skeletal M (MA&F)
-Cylindrical
-Multinucleated
-Long
-Striated
Voluntary Control
Cardiac M (MA&F)
Branched
Single Nuclues
Striated
Intercalated discs
Autonomic Control
Smooth M (MA&F)
Smooth
Tapered
No striations
Single Nucleus
Autonomic Control
Ex. Digestive Tract
Epimysium
Outside Connective tissue cover around whole muscle
Perimysium
Covering that gathers around group of muscle fibers/Fasicle
Endo-Mysium
Deepest Covering that gathers around individual muscle cell
Origination Place of Tendon
They come from the coming together of epi, peri, and endo-mysiums
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
Fascia
collagen rich Connective Tissue covering found around (MUSCLE GROUP)
Sacrolemma
Membrane of muscle cell
Alpha motor neurons
Neurons that stimulate Skeletal Muscle cell
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
- Excitation
- Excitation-Contraction coupling (ACh to Muscle AP)
- Contraction
- 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
