T9 Muscular Tissue

muscle tissue functions

movement, heat generation, posture, joint stabilization

muscle tissue properties

irritability, contractility, extensibility, elasticity

skeletal muscle morphology

striations, multinucleated at peripheral

smooth muscle morphology

fusiform shape with one nucleus in center

cardiac muscle morphology

only one nucleus that is bigger, presence of intercalated disks and branching, striated, more space between

muscle fiber

muscle cell

myofilaments

actin (thin), myosin (thick)

sarcolemma

plasma membrane

sarcoplasm

cytoplasm

epimysium

wrap around whole bundle

muscle fascicle wrapped by

perimysium

muscle fiber wrapped by

endomysium

endomysium contains

satellite stem cells, capillaries, nerves

sacromere

unit of muscle contraction, z disc to z disc contracting towards m line

z disc

actin filament anchor

m line

light striation

A band

overlapping area of actin and myosin; dark

I band

actin only; light

sarcoplasmic reticulum (SR)

store calcium

T tubule

cell membrane extension into sarcoplasm

terminal cisternae

area of SR for calcium storage

muscle triad

T tubule and 2 cisternae

myosin structure

golf club shape with actin binding site and atpase site

actin structure

g actin with myosin binding site arranged in chain, tropomyosin run along myosin binding site, troponin bind to calcium to free the binding site

neuromuscular junction release

acetylcholine

acetylcholine triggers

action potential

action potential propagates along

T tubules

calcium binds to

troponin

myasthenia gravis

auto-antibody of acetylcholine receptor which blocks acetylcholine and inhibits muscle contraction

duchenne’s muscular dystrophy

inherited, dystrophin degeneration leading to muscle atrophy

intercalated disc

gap junction to transmit ions as fast as we can so heart contracts at same time

cardiac muscle organization

diad (1 T tubule, 1 cisternae)

smooth muscle arrangements

inner circular, outer longitudinal

smooth muscle cell needs

extracellular calcium

“sacromere” of smooth muscle is called

dense bodies

myosin head orientation

side polar