Structure of Muscle Tissue X Flashcards
Muscle Fxns
Movements
Support
Heat
Muscle Classification
Skeletal, Cardiac, Smooth
Striated/Non-Striated
Voluntary/ Non-Voluntrary
Striated Muscle
Skeletal
Cardiac
Involuntary Muscle - types, control
Cardiac
Smooth
Autonomic Nervous System (vs. Cerebral Cortex)
Muscle levels (Macro->Micro)
Muscle -> Muscle Fascicle -> Fiber -> Myofibrils -> Sarcomere -> Actin (thin) & Myosin (thick)
Epimsyium
**
dense irregular CT surrounding - all fascicles that constitute a muscle-
Perimysium
**
dense irregular CT surrounding - individual fascicles -
Endomysium
**
Reticular fibers surround - individual muscle fibers
CT layers on muscle - types, fxn
Epimysium, Perimysium, Endomysium
Conduit for circulatory and nervous supply to muscle
Thin Filaments - COmponents
Actin
Tropomyosin
Troponin Complex
Tropomyosin
**
protein - forms double helical structure lying in the groove of actin helix. Acts with troponin complex to regulate myosin- actin binding
Troponin complex - components/fxns
**
TnI - actin binding protein - prevent actin to myosin
TnT - tropomyosin binding protein - troponin complex to actin
TnC - calcium binding protein for contraction
Thick Filaments - components
Myosin Heavy Chain
Myosin Light Chain 1
Myosin Light Chain 2
Myosin Heavy Chain - def, fxn
**
protein with alpha helical ‘rod’ and globular ‘head’
binds ATP and actin
Myosin Light chain 1 & 2 - fxn
phosphorylation helps regulate calcium stimulation of contraction. (smooth muscle)
Sacromere - Components
Z line/disc I band A band H band M-line
Z line
anchor for actin
M line
center of sacromere
anchor for myosin
I band
thin filaments NOT overlapping with thick filaments
light staining
A band
length Myosin
thick filament and overlapping thin filaments
dark staining
H band
thick filament NOT overlapped by thin filaments
straddles center
Effect of Contraction on sacromere components
I and H bands shorten
Z lines move together (towards M center)
A DOES NOT change
Transverse Tubeles - def., fxn
***
Tubular invagination of the muscle cell plasma membrane closely aligned with cisternae of sarcoplasmic reticulum
T-tuble allows for changes in membrane electrical potentials to reach SR (a Ca2+ reservoir) thereby regulating calium concnetration anf nuscle contraction
Triad
**
triple structure consisting of two terminal cisternae flanking a T-Tubule at the A-I band junction
neuromuscular junction - def, a.k.a
**
synaptic connection between a motor axon and the muscle fiber
motor end plate
junctional folds - def
where axon terminates on the muscle cell
Denervation Atrophy
loss of stimulation to the muscle cell at the neuromuscular junction leading to muscle atrophy
Muscle spindle - fxn, sturcture, significance
**
Detect the amount of stretch of a muscle
Basis of stretch reflexes
Modified muscle fibers inside inner of two capsules allows for proprioception
Hypertrophy - action, affected by
**
increases the size of myofibrils and the number of myofibrils per muscle cell
Age
Nutrition
Hormones
Myasthenia gravis
**
autoimmune disease with progressive muscular weakness and atrophy
reduction in # of ACH receptors in sarcolemma at NMJ
Muscular Dystrophy
**
congenital muscle disease
Severe weakness atrophy and destruction of muscle fibers
caused by genetic mutations in transmembrane proteins of dystrophin-glycoprotein complex
Cardiac Muscle - components
**
one centrally located nucleus
Intercalated disks
Dyads
Increased mitochondria, lipid droplets, glycogen and myoglobin
contraction controlled by both autonomic nervous system and circulating horones
Intercalated Disks - fxn
**
highly specialized attachments that join cardiac muscle fibers together
Junctional Complexes in Cardiac Muscle
**
Fasciae Adherens
Maculae Adherens
Gap Junctions
Smooth Muscle - components
**
Fusiform
Lack of cross-striations and T-tubules
Single centrally located nucleus
Smooth Muscle - locations
tubuar organs - lining iris and ciliary body of the eye scrotum blood vessels hair follicles
Gap Junctions in Smooth muscle - fxn
allow intercellular communication regulating contraction of sheets
Smooth muscle capable of hyperthrophy and hyperplasia
**
KNOW
Regenration in muscle
**
Skeletal - Yes
Smooth - Sort of
Cardiac - None
Promotion of Muscle Fiber Shorterning
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Hyperplaisia
Increase in cell number
Smooth muscle capable of hyperplasia and hypertrophy
