Lecture 7 - Muscle Histology Flashcards
______is a single mature muscle cell.
Myofiber or muscle fiber or myocyte
the muscle cell membrane
Sarcolemma
the cytoplasm of the muscle cell
Sarcoplasm
smooth endoplasmic reticulum (sER) known as what in muscle
Sarcoplasmic reticulum
dense connective tissue sheath covering the entire muscle.
Epimysium
derives from epimysium and surrounds the bundles or fascicles of muscle cells
Perimysium
delicate layer of reticular fibers and extracellular matrix surrounding each muscle cell
Endomysium
Sarcomere extends from where to where
Z line to Z line, consits of 1/2 I band, complete A band, 1/2 I band
The A band is bisected by a light region called the _______
H band
The major component of H band is the enzyme _________ , which catalyzes the formation of ATP from creatine phosphate and ADP .
Creatine Kinase
Running through the middle of the H band is the ________
M line
Thick filaments known as
Thin filaments known as
Myosin
Actin
Regulatory proteins on actin
tropomyosin and troponin
Triad consists of what
2 Terminal cisternae and 1 T tubules
What does the triad do?
depolarization of sarcolemma in a T tubule to affect the sarcoplasmic reticulum and trigger release of Ca⁺⁺ ions into the cytoplasm around the thick and thin filaments , which initiate contraction of the sarcomeres
Is an autoimmune disorder in which antibodies are produced against acetylcholine receptors.
Antibodies bind to the receptor , preventing the binding of acetylcholine .
This blocks the normal nerve – muscle interaction and results in progressive muscle weakness .
The extra ocular muscles of the eye are commonly affected first .
Myasthenia gravis
Each muscle spindle has concentric layers of flattened cells , containing interstitial fluid and a few thin muscle fibers , called
Intrafusal fibers (Sense changes in length and send infot to spinal cord
much smaller encapsulated structures that enclose the sensory axons penetrating the collagen bundles at the muscle – tendon junction .
They detect changes in tension within tendons produced by muscle contraction and act to inhibit motor activity if tension becomes excessive.
Golgi tendon organs
are adapted for slow contractions over long periods without fatigue. They have many mitochondria , rich capillary network and much myoglobin ( dark fibers or red fibers)
Slow oxidative muscle fibers
specialized for rapid , short term contraction , have few mitochondria , few capillaries and depend largely on anaerobic metabolism of glucose from stored glycogen. These fibers appear white and they fatigue rapidly
Fast glycolytic fibers
have physiological and histological features intermediate between those of other 2 types
Fast oxidative – glycolytic fibers
- are of considerable significance in muscle maintenance, repair and regeneration .
- are mitotically quiescent in adults , but can resume self – renewal and proliferation in response to stress or trauma. This is the basis of stem cell therapy of a number of muscle injuries and degenerative diseases including muscular dystrophies.
Satellite cells
