Muscle Flashcards
sliding-filament model
hypothesis that thin filaments (actin) & thick filaments (myosin) slide past one another during contraction
- sliding shortens sacromere
- 1954 - proposed by Huxley & Hanson (individually @ same time)
evidence of sliding filament model of muscle contraction
light & dark bands in sacromere changed when muscles relaxed or contracted
- light bands become narrower
- dark bands no change
types of muscle
(1) cardiac muscle
(2) smooth muscle
(3) skeletal muscle
cardiac muscle
type of muscle
location: heart
function: move food & help regulate blood pressure
properties: involuntary
striated due to sacromeres
smooth muscle
type of muscle
location: intestines, arteries, digestive tract, lungs, etc.
function: pump blood
properties: involuntary
skeletal muscle
type of muscle
location: attached to skeleton
function: move skeleton
properties: voluntary
striated due to sacromeres
level of muscle organization
(1) muscle
(2) muscle fiber/cell
(3) myofibril
(4) sacromere
adenosine triophosphate (ATP)
causes conformational change by releasing head from actin in thin filament
adenosine diphosphate (ADP)
causes myosin neck to straight & head to pivot
- mysosin head bonds to new actin subunit
sacromere
smallest component of muscle
- contractile unit
- Z disc to Z disc
myosin
binding sites on thin filament
tissue
group of cells that function as a unit
types of tissue
(1) epithelial
(2) connective
(3) muscle
(4) nervous
epithelial tissue
tissues that cover or line
connective tissue
if not other 3 tissue then it is connective tissue
(ie) bone tissue & blood cells
thick filament
purely myosin
MC
thin filament
actin
location of myosin binding
regulated by: troponin & tropomyosin
AN
Z disc
where sacromere attaches
- protein
crossbridge cycle
(1) myosin/myosin
(2) myosin/actin
(3) myosin/ATP
rigor mortis
muscles are contracted
ATP hydrolizes
you’re stiff because you’re stuck
“stiffness of death”
motor neuron
neuron that make up muscle
- action potential firing
- acetylcholine
acetylcholine
not a protein, lipid, sugar or nucleic acid
“other” category
action potential
(1) receptor binds to channel (acetylcholine)
(2) channel signals through T-tubule
(3) releases Ca+ ions
muscle relaxed
ATP cannot attach
troponin binds Ca+, which causes shift in tropomyosin (allowing it to be accessible)
muscle contraction
ATP attached
tropomyosin accessible
