Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
Fascicles
|
groups of muscle fibers/myofiber
|
|
|
Perimysium
|
c.t. that surrounds each fascicle
|
|
|
Muscle Fiber/Myofiber
|
elongated, multinucleated, striated cell
|
|
|
Endomysium
|
c.t. that surrounds individual muscle fibers/myofibers within a fascicle
|
|
|
Sarcolemma
|
cell membrane of a muscle fiber/myofiber
|
|
|
Myofibril
|
hundreds of thousands of closely-packed, parallel, threadlike structures within the muscular fiber/myofiber
intracellular the banding makes it appear striated |
|
|
Sarcoplasmic Reticulum (SR)
|
Myofibril are covered by elaborate sleeves of smooth endoplasmic reticulum
|
|
|
Terminal Cisternae
|
SR tubules fuse into sac-like elements
Store and release Calcium when the fiber is stimulated to contract |
|
|
T-Tubules
|
extensions of muscle fiber membrane (sarcolemma) that penetrate the cell and extend from one side to the other
|
|
|
myofilament
|
make up the myofibrils
consists of proteins |
|
|
Thin Filaments
|
"Actin Filaments"
|
|
|
G Actin
|
active sites for binding, on thin filaments
|
|
|
synaptic cleft
|
the space between the terminal end of the axon and the single muscle fiber
|
|
|
vesicles
|
in the axon end, contain acetylcholine (ACh)
|
|
|
Motor end plate
|
highly folded sarcolemma, post-synaptic
|
|
|
polarized
|
the inside of the cell membrane is negative compared to the outside of the cell
|
|
|
exocytosis
|
vesicle fusion to presynaptic membrane
|
|
|
2 Factors that influence muscle contraction
|
-Changing frequency of stimulation
-Changing strength of stimulus (Motor Unit Recruitment) |
|
|
Motor Unit Recruitment
|
varying the number or size of motor units recruited, to control the degree of contraction
|
|
|
3 Types of Skeletal Muscle Fibers
|
1. Slow Twitch (red) oxidative fibers
2. Fast Twitch (red) oxidative fibers 3. Fast Twitch (white) glycolytic fibers |
|
|
motor unit
|
motor neuron and ALL the muscle fibers it innervates
|
|
|
motor nerve
|
each muscle has at least one
contains hundreds to several thousand nerve cell axons |
|
|
Isotonic Contraction
(includes concentric and eccentric) |
-"Same Tension"
-once tension is developed to lift the load, tension remains constant -Muscle changes length -Thin Filaments slide |
|
|
concentric Contraction
|
muscle shortens, does work
|
|
|
Eccentric Contractions
|
muscle generates force when it lengthens
|
|
|
Isometric Contraction
|
-Pushing over a wall
-Tension increases until reaching peak tension -muscle neither shortens or lengthens -thin filaments do not move |
|
|
Tonic Contraction
|
-motor units contacted asynchronously
-produces a continual, partial contraction -delays fatigue |
|
|
3 roles of ATP in muscle contraction:
|
1. Disconnect the myosin cross bridge at conclusion of power stroke
2. Re-energize myosin head in preparation for next power stroke 3. Actively transport Ca back into the SR |
|
|
What are the ONLY cells that are excitable?
|
nervous and muscular tissue
|
|
|
What is the ONLY cell that has contractility
|
Muscle Tissue
|
|
|
4 Muscle Functions
|
1. Produce Movement
2. Maintain Posture 3. Stabilize Joints 4. Generate Heat |
|
|
Skeletal Muscle is what percentage of body mass?
|
40%
|
|
|
Curare
|
Indian arrowhead poison that binds strongly to acetylcholine receptors but does not change membrane permeability
|
|
|
Botulinum Toxin
|
block release of synaptic vesicles at the NMJ
|
|
|
Cholinesterase inhibitors
|
in a number of pesticides, prevent the break down of ACh at NMJ
cannot breathe out |
|
|
Approximately how long is the refractory period?
|
1 millisecond (1/1000 seconds)
|
