Shared Flashcard Set

Details

Muscular System
Gideon Shemer's BIOL 252
28
Anatomy
Undergraduate 3
11/02/2011

Additional Anatomy Flashcards

 


 

Cards

Term
perimysium
Definition
The outer sheath of connective tissues that groups muscles together to form fasicles.
Term
Endomysium
Definition
Layer of connective tissue that sheaths the muscle fiber specifically composed from reticular fibers. Overlies the sarcolemma.
Term
epimysium
Definition
Outer layer of connective sheath that holds together all the fascicles. Ensheaths the entire muscle. Dense irregular connective tissue
Term
sarcolemma
Definition
Plasma membrane of the muscle fiber cell.
Term
T-Tubules
Definition
Tubular infoldings that penetrate through the cell and emerge on the other side. Function to convey electrical signals from the cell surface to its interior- signals the SR when to release the calcium bursts to activate muscle contraction
Term
myofibril
Definition
Long cylindrical protein chains in the cytoplasm that are composed of myosin and actin. Muscle contraction occurs when these slide past each other.
Term
Sacromere
Definition
Each segment of a myofibril from one Z disc to the next. The functional contractile unit of the muscle fiber.
Term
Z-line
Definition
Protein disc found in the middle of the I bands that anchors thin filaments at the end of sacromeres
Term
Actin
Definition
Found on the thin filaments, F unit is composed of G units. Each has an active site that binds to the head of myosin, blocked by the tropomyosin heads.
Term
Myosin
Definition
Protein that makes up the thick filaments. Heads directed outward in helical array around bundle, bind to actin sites.
Term
I-band
Definition
Light band composed of thin filaments only.
Term
H-band
Definition
Thick filament portion of sacromere
Term
A-Band
Definition
The Dark band formed by the thick and thick/thin filaments overlying each other.
Term
Tropomyosin
Definition
Regulatory protein that lies in F actin and blocks the myosin binding active sites.
Term
Troponin
Definition
Receptor for Ca++ found on the tropomyosin. Alters configuration of tropomyosin to allow active sites for actin-myosin binding to take place
Term
Neuromuscular Junction
Definition
The point where a nerve fiber meets a muscle fiber. This is the actual synapse. Several points of stimulation. Release of ACh reaches on of 50mil receptors
Term
Motor End Plate
Definition
Another name for the neuromuscular junction.
Term
Acetylcholine
Definition
Released from nerve cells via synaptic vesicles. Acts as the chemical messenger from nerve cell to muscle cell. (SOMATIC MOTOR TO SKELETAL MUSCULAR)
Term
Acetylcholinesterase
Definition
Enzyme that is responsible for breaking down ACH after it has stimulated the muscle cell for contraction.
Term
Excitation-Contraction Coupling
Definition
Events that link the action potentials on sarcolemma to activation of myofilaments.
1. AP spreads from NMJ through T-Tubules+Sarcolemma
2. AP open voltage regulated ion gates in T Tubules, allowing calcium into SR, SR opens and calium diffuses into cytosol
3. Calcium bind to troponin, altering configuration of tropomyosin exposing active sites for actin heads to bind.
Term
Myasthenia Gravis
Definition
Autoimmune disease found in women where antibodies attack NMJ and bind ACH receptors together. Muscle fibers remove clusters, making them less sensative to ACh. Leads to double vision, diffiuclaty swallowing, weakness of limbs. Treated with cholinerase inhibitors that prevent breakdown of ACh.
Term
Muscular Tension
Definition
The force exerted by a contracting muscle on an object by the muscle as an organ
Term
Motor Unit
Definition
One nerve fiber and all the muscle fibers innervated by it.
Term
Isometric Contraction
Definition
Muscles contract without changing length and without causing movement
Term
Isotonic Contraction
Definition
Muscle lengths change during muscle contraction, movement takes place (shortens or lengthens).
Term
Twitch
Definition
Response of a muscle fiber to a single action potential
Term
Dense Bodies
Definition
Thin bodies attach to this, rather than the Z-disc.
Term
Gap Junctions
Definition
Innervation of single-unit smooth muscle cells that conducts electrical signals through the muscle cell.
Supporting users have an ad free experience!