Physiology of Muscles Flashcards
functions of the muscular system
movement, posture and position, constriction of organs and vessels, guard entrances and exits, body temperature, respiration, communication
general properties of muscle
contractility, excitability, extensibility, elasticity
anatomy of skeletal muscle
gross anatomy
- connective tissue: fascia
- epimysium
-tendon
- perimysium
- fascicule
- endomysium
nerves and blood vessels
connective tissue: fascia
connective tissue around whole muscle, keeps muscle separate from skin
epimysium
connective tissue around whole muscle
tendon
connective tissue coming off the muscle, going to bone
perimysium
divides muscle into smaller sections. blood vessels and nerves travel through to get where they need to go
fascicule
one section of muscle tissues
endomysium
connective tissue around individual muscle cells
nerves and blood vessels
changeable, can change the number of blood vessels and nerve connections you have
microanatomy
-fiber
-sarcolemma
-sarcoplasm
-transverse tubules
-sarcoplasmic reticulum
-myofibrils
- sarcomere
- actin
- myosin
fiber
cell, long and skinny
sarcolemma
membrane
sarcoplasm
cytoplasm, fluid inside muscle fiber
transverse tubules
tubes that go deep into muscle fibers from surface. can carry electrical charges
sarcoplasmic reticulum
parallel to axis of fiber. holds calcium
myofibrils
bundles of proteins in muscle fiber, run the whole length of the fiber
sarcomere
functional unit of a muscle
actin
thin protein strand in the sarcomere
myosin
thick band of protein with multiple heads
muscle contraction
mechanics inside a myofibril/sarcomere
- cross bridges
- troponin
- tropomyosin
cross bridges
myosin head connected to action. myosin head connects to active sites on the action. ATP is used to let go
troponin
bead like protein attached to actin and tropomyosin, likes to connect with calcium. when calcium connects to troponin it changes the shape, when this happens, the tropomyosin is moved off the active sites
tropomyosin
ribbon like protein. lies along actin, covering active sites. its job is to cover and get pulled of the active sites
inside a muscle fiber, outside myofibril
- transverse tubule
- sarcoplasmic reticulum
T tubule
an action potential travels down the T tubule and hits a VSP, which changes shape when it gets hit. VSP has a foot like projection that is connected to calcium gate in the SR…opens gate
sarcoplasmic reticulum
high concentration of calcium in it, so when gate opens, Ca will flood out through diffusion
surface of the muscle fiber
- motor endplate
- sarcolemma
motor endplate
part of sarcolemma that receives neurotransmitter. motor endplate starts and action potential
sarcolemma
action potential goes all over sarcolemma and down the T tublules
muscle stimulation
motor neuron
kind of neuron that tells something what to do
euromuscular junction
where neuron and muscle communicate, don’t actually touch
acetylcholine
name of neurotransmitter that tells muscle to contract
motor units
a neuron and all the muscle fiber it contains
motor learning gives us coordination…which unit to fire and in what order
energy for contraction
ATP
CP
anaerobic respiration
aerobic respiration
oxygen debt
ATP
always making and using
2-3 seconds worth floating in muscle cell
CP
creatine phosphate, energy in bond that is easily broken. that energy can be used to make ATP, there is no waste product.
it also holds energy in the muscle cell
you can only use what you have…have 6 seconds worth in the muscle cell. it takes 5-8 min to put it back together
anaerobic respiration
using food and getting energy out of it
without oxygen
glycolysis
happens in sarcoplasm
can do for 30-40 seconds before creating waste product/Lactic acid
outside the mitochondria-high intensity(sprinting)
lactic acid changes the PH which causes fatigue
at rest ATP remakes creatine phosphate
+2ATP, +2NADH
aerobic respiration
just in the mitochondria, no limit. always going until die
gives more ATP than anaerobic
in mitochondria… 2 processes, Krebs and oxidative
glucose(C6H12)6) becomes pyruvate during glycolysis then pyruvate goes to mitochondria then is changed into 6H2O and 6CO2
+2ATP, + 36 ATP
1 glucose molecule gives grand total of 38 ATP
waste product = CO2 and H2O
oxygen debt
when breathing heavy after exercise is done
- anaerobic to the point of making LA
4 reasons
- need extra O to help restore stored ATP
- so can replace CP
- to help get rid of LA, along with breathing heart rate up LA goes into heart and use as fuel
- repair the muscle cell
muscle fatigue
high intensity exercise
- change in PH of cell, doesn’t contract as well
- run out of ATP
- sprinting and jumping
low intensity exercise
- jogging
1. decrease motivation drive: motivation trumps fatigue…physiological
2. decreased intra muscle fuel supply: run out of fuel in muscle cell - glucose
3. decreased extra muscle fuel: extra glucose, sugar in blood
4. decreased O2 delivery to working skeletal muscle: less blood to working muscles, temp-rather run in the cold than hot
muscle fiber types
type 1
type 2a
type 2b
always uning type 1 fibers. harder activity, more type 2a and type 2b used
type 1
“slow twitch”
endurance, always used
stay skinny
posture and leg muscles
myoglobin(high)
blood vessels(many)
mitochondria(high)
ATPase(slow)
type 2a
“fast twitch”
speed
get bigger
legs
myoglobin(med)
blood vessels(med)
mitochondria(med)
ATPase(med)
type 2b
“fast twitch”
power(explosive), last recruit
get bigger
arms
myoglobin(low)
blood vessels(low)
mitochondria(low)
ATPase(fast)
Isotonic
contraction where use same amount of force
isometric
same length
using muscle
-working but not changing length
-posture muscles
using all the time to stay still
isokintic
speed controled
prime mover
main muscle doing action
synergist
helper muscle
antagonist
muscles that do the opposite action
concentric
when muscle that’s working gets shorter
eccentric
when muscle that’s working gets longer
origin
where a muscle is anchored
less movable
insertion
where a muscle is moving a bone
more moveable
smooth muscle
no striations/strips…gets name from what looks like
involuntary
around BV and air passageways, intestines: more internal
stretching makes it contract, helps blood pressure-always pushing
less than 1% mitochondrial volume
cardiac muscle
has stripes
involuntary
40% mitochondrial volume
-never going anaerobic
-aerobic 100% of time
