Exam 3 Flashcards
muscle structure
functional unit= sarcomere with Z line borders
muscle fiber(cell) >myofibril> myofilaments (actin and myosin)
how does an action potential trigger a muscle contraction
acetylcholine, from synaptic terminal of motor neuron, depolarizes the muscle cell-which causes the action potential
role of ATP in muscle contraction
role of calcium in muscle contraction
cross bridge cycle
role of sarcoplasmic reticulum in regulating muscle contractions
smooth muscle
actin and myosin are not arranged in any particular way
spongey, contracts in same direction all over
striated muscle
striped in appearance, skeletal and cardiac muscle, actin and myosin arranged in parallel
tetanus
summation of muscle twitches
graded contractions
muscle recruitment
motor neuron recruitment results in stronger contractions- rapid gains upon first lift
muscle growth and repair
the number of actin and myosin filaments within a myofibril can increase, muscle cells do not increase
role of satellite cells
repair and growth
regeneration and production of actin and myosin filaments
stimulated by insulin-like growth factor (IGF) released by stressed muscles
energy metabolism in muscles (1)
mitochondrial aerobic metabolism
oxidative phosphorylation
allows for long term steady state activity
energy metabolism in muscle (2)
glycolysis
high intensity activities
produces lactic acid in bloodstream
burning feeling comes from decrease in pH since glycolysis produces H+
energetic shortfalls when glycogen stores are out
glycolytic fibers
use glycolysis as their primary source of ATP
less myoglobin and tire more easily
fast twitch fibers -type 2
contract rapidly and forcefully, shorter contractions
glycolytic- type 2a
glycolytic and oxidative- type 2b (majority)
oxidative fibers
aerobic respiration to generate ATP-produced by mitochondria, produces ATP slower but more efficient
fibers contain a lot of mitochondria and myoglobin
very red in color
slow twitch fibers, type 1
lactate (lactic acid) as fuel? as problem?
lactate converted to glucose in liver
lactate oxidized to CO2 by mitochondria in aerobic muscle
has to get used quickly to get H+ donor out of blood because H+ will drive pH down-more acidic muscle
oxygen debt
rates of oxygen consumption remain elevated after exercise has ceased- high respiration rate
metabolic transitions
for prolonged exercise, metabolic fuels must be mobilized for ATP production
type of fuel being used can be monitored by measuring the respiratory quotient (RQ)
hormones cause transitions between fuel type
respiratory quotient
CO2 production/O2 consumption
lipids= 0.7
carbohydrate= 1.0
fuels and hormones
cortisol- release lipids
epinephrine- burn glucose
during steady state activity- utilize whichever fuel is abundant
oxygen delivery
diffusion: small animals with low metabolic rates (O2 from water down concentration gradient into body)- nematodes and flatworms
cardiovascular system: vertebrates
tracheae (indentations in body): active insects like bees and grasshopers
how is capacity to deliver O2 increased within muscles
hypoxic zones cause capillaries to grow
hormonal role in oxygen delivery
capillaries and capillarization
hypoxic zones
hypoxic zones cause capillaries to grow
hormone involvment in capillarization
myoglobin
skeleton types
skeleton-muscle interactions
type 1 lever
type 2 lever
type 3 lever
mechanical advantage
energy storage
force and velocity
power
receptor cell structure and function
afferent nerves
generator potential
receptor potential
graded potentials
receptor types
adequate stimulus
ampullae of lorenzini
encoding of stimulus
theory of labeled lines
receptive fields
lateral inhibition
dynamic range
range fractionation
tonic receptors
phasic receptors
