chapter 9 Flashcards
All prefixes for muscle
Myo, mys,sacro
skeletal
attached to bones ( or some facial muscles) to skin
Cardiac
Walls of the heart
Smooth
Unitary muscle in walls of hollow visceral organs ( other then the heart ) multi unit muscle in intrinsic eye, muscles, airways ,large arteries
innervation
It has neural input, atleast one neuron is intact with that muscle
vascularity
A typical characteristic of connective tissues, denoting that they have a rich blood supply
epimysium
a sheath of fibrous elastic tissue surrounding a muscle.
Perimysium
Connective tissue surrounding a fascicle
Endomysium
Connective tissue surrounding a muscle fiber
Connective tissue sheaths
epimysium, perimysium, endomysium
origin and insertion
-Origin: immovable end of muscle
-Insertion: movable end of muscle
direct vs indirect
Taking action oneself versus enlisting the help of an intermediary who takes the direct action
Sarcolemma
muscle cell membrane
Sarcoplasm
cytoplasm of a muscle cell
glycosomes
glycogen storage
modified organelles
myofibrils, sarcoplasmic reticulum, t-tubules
myofibrils
protein structures that make up muscle fibers
sarcoplasmic reticulum
Organelle of the muscle fiber that stores calcium.
t-tubules
Also called transverse tubules, these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.
myofilaments
actin, myosin, titin
clinical consideration
Duchenne muscular dystrophy, almost exclusively male, defective dystrophin gene
sarcoplasm reticulum
stores ca2+ , releases and reuptakes ca2+, terminal cisternae, t-tubules, triad
relaxed muscle fiber
area that overlaps myosin and actin
Four steps for skeletal muscle to contract
- events at neuromuscular junction
2.muscle fiber excitation
3.Excitation-contraction coupling
4.Cross bridge cycling
NMJ Events
-axon
-axon terminal
-action potential
-VGCS open
-Vesicular exocytosis
-acetocholine diffusion
-ACh binds, open Na+ channels
Events at the neuromuscular junction
- Action potential at axon terminal
2.Ca VGC opens, Ca enters - ACh exocytosis
4.ACh diffuses to NA chemical gates - ACh binds to receptors opens gates, Na enters = end plate potential
6.Achase degrades ACh
Generation of End Plate Potential
- End plate potential is generated
- Depolarization
- Repolarization
Excitation contraction coupling
events that link the action potentials on the sarcolemma to activation of the myofilaments, thereby preparing them to contract
cross bridge cycle
- cross bridge formation
2.power stroke - cross bridge detachment
- Cocking of myosin head
Calcium (Ca2+) and ATP concentration
- low intracellular ca2+
- high intracellular ca2+
-insufficient ATP concentration - sufficient concentrations
Whole muscle contraction
- contraction produces muscle tension
- contraction =/= shortened muscle
motor unit
one neuron and all the skeletal muscle fibers intermix
muscle twitch phases
- latent period
2.period of contraction
2.period of relaxation
graded muscle Reponses
Changing frequency of stimulation
- temporal summation
Graded muscle responses
changing strength of stimulation
type of contractions
isometric contractions, isotonic contractions
muscle tone
Constant slightly contracted state of all muscles
direct phosphorylation of ADP by creatin phosphate
creatine phosphate, creatine kinase
Anaerobic pathway glycoses and lactic acid formation
glucose to glycoses to pyruvic acid to lactic acid
aerobic pathway
glucose broken into CO2, H2O and 32 ATP
