Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/10

Click to flip

10 Cards in this Set

  • Front
  • Back
Muscular Tissue
organized single direction contraction
MYOCYTE=Muscle Fiber =Myofiber
-acidophilic due to microfilaments
Organization
-Epimysium: each muscle covered by dense irregular CT/fascia
-Perimysium: covers ind. muscle fasicles
-Endomysium: each cell surrounded by CT
Light Microscopic structure
-elongated cell with peripheral multiple nuclei
-contian many myofibrils
-myofibrils contain many thick and thin myofilaments
-I band=isotropic does not change plane of light so light in color, only thin myofilaments
-A band=anisotopic changes plane of light, dark colored, thick and thin filaments overlap

in btw myofibrils are mitochondria and glycogen

nucleus on periphery due to myofibrils filling up the cell

adv to longer fibers is more force of contraction more rapid single nerve can innervate many fibers (motor unit)
ELectron microscopic
T-tubule system of skeletal muscle:
invaginations from sarcolemma at level of A-I bands
encircle myofibrils

Conducting system (muscle triad)
-Sarcoplasmic reticulum (sER) network surrounds individual myofibrils
-sarcoplasmic reticulum dilate to form terminal cisterae at A-I band level
-One t-tubule and two terminal cisternae form a triad
-take wave of depolarization from nerve on surface inside cell
cont'd
conduction system (motor end plate)
-nerve axon-muscle cell contact

Myofibrils
-muscle cells contain myofibrils composed of myfilaments
-thick myosin2
-thin actin tropomyosin and troponin
-binding proteins actinins and tinin at z-line and m-line proteins
-nebulin regulates assembly and length of actin, desmin links adjacent myofilaments, spectrin and dystrophin connect myofilaments to cell surface
Thick and Thin myofilaments
Thick
-2 heavy chains
-4 light chains associated with globular heads
-globular head have binding site for actin and Atp

Thin
-double helix of f-actin having myosin binding sites
-tropomyosin located in groove covering binding sites
-troponin binds actin thus preventing myosin from binding
-increased calcium moves troponin and tropomyosin allowing binding
Banding
A
thick overlapping with thin
I
thin myofilaments
H
w/o thin
M
thick connected contains creatinine kinase enzyme for atp maintenance
Z
thin of adjacent sarcomeres anchored
alpha-actinin, myosin2 attach to z line by spring like protein, tinin
classification
see table in notes
myogenesis
hypertrophy
by satellite cell division
individual myocytes do not divide
atrophy
loss of nuclei and myofibrils
regeneration
small repair done by satellite cells by fusion with existion myocytes and forming new myocytes
large repair by replacing with CT scar
satellite cells
stem cells sit with them
-spindle shaped
-heterochromatic, single nucleus
-inactive myoblast in adult
-immature muscle cell