PHYSIOLOGY - muscle, bone, cartilage, joints Flashcards
is skeletal muscle voluntary/involuntary and striated/unstriated
voluntary
striated
is smooth muscle voluntary/involuntary and striated/unstriated
involuntary
unstriated
is cardiac muscle voluntary/involuntary and striated/unstriated
involuntary
striated
what is a motor unit in skeletal muscle
single alpha motor neuron + all the muscle fibres it innervates (depending on the function the number of muscle fibres is different)
in something with precision (eg eye movement) are there lots or few muscle fibres in each motor unit
few
just have lots of motor units
in something with power over precision (eg muscles) are there lots or few muscle fibres in each motor unit
lots
no point in having lots of motor units/alpha motor neurones if all the muscles fibres are being programmed to do the same thing
is myosin a thick or thin filament
thick
is actin a thick or thin filament
thin
in muscle contraction, where does the Ca2+ come from
sarcoplasmic reticulum
what happens when Ca2+ is released from sarcoplasmic reticulum in muscle fibres
binds to troponin on actin
is Ca2+ present or absent when contraction occurs
present
is Ca2+ present or absent when relaxation occurs
absent (it is actually released)
is ATP required for muscle contraction to occur
yes
is ATP required for muscle relaxation to occur
yes
where is the Ca2+ pumped into when muscle relaxation occurs
from actin myosin crossbridge to sarcoplasmic reticulum
why does rigor mortis happen
bc theres no ATP for relaxation of muscles
what are the components of muscle tension (3)
number of muscle fibres involved
frequency of stimulation of fibres
summation of contractions
what happens when an action potential occurs before the previous twitch is finished
twitch summation (can eventually turn into one strong contraction)
how does twitching of muscles happen in cardiac muscle
it doesnt!
long refractory period prevents twitching from happening
what is the physiology of isotonic contraction
when is it used
muscle tension stays the same
length of fibre changes
(isoTonic = Tension same)
body movement and moving objects
what is the physiology of isomeric contraction
when is it used
length of muscle stays the same
muscle tension increases
maintain body pressure eg holding something for a long time
what are slow oxidative muscle fibres used for
prolonged low work aerobic activities
eg walking, posture
what are there lots of in slow oxidative muscle fibres
mitochondria (bc they need oxygen)
what are fast oxidative muscle fibres used for
prolonged but moderate work activities
eg jogging
do we have many fast oxidative muscles
no mainly slow oxidative and fast glytolytic muscle fibres
what are fast glytolytic muscle fibres used for
high intensity activities
eg jumping
what are there lots of in fast glytolytic muscle fibres (2)
glycogen
enzymes for glycolysis
not much mitochondria bc no oxygen needed
what are muscle spindles
sensory receptors for muscle stretching (increase firing when stretched)
what nerve is knee jerk testing
femoral
what nerve is ankle jerk testing
tibial
what nerve is biceps jerk testing
musculocutaneous
what nerve is brachioradialis jerk testing
radial
what nerve is triceps jerk testing
radial
how is cartilage nourished
diffusion from extracellular (it is avascular)
what are chondroblasts
immature chondrocytes
where are chondrocytes
in lacuna (extracellular matrix) of cartilage
what do chondrocytes secrete
extracellular matrix - water, type II collagen, proteoglycans
where do you find hyaline cartilage
nose
lots of places - most common
where do you find elastic cartilage
ear
where do you find fibrocartilage
pubic symphysis
intervertebral disc
is cartilage permeable
yes
is bone permeable
no
how are bones nourished
blood supply (vascular)
what are the blood vessel canals called that supply the bone
haversian canal
volkmanns canal
what is an osteocyte
cell in bone matrix
‘Chews’ bone
what is an osteoblast
bone forming cells on cell surface
osteoBlast = bone is ‘Born’
what is an osteoclast
responsible for bone resorption on cell surface
osteoClast = bone is ‘Chewed’
what is an osteoprogenitor cell
pool of reserve osteoblasts on bone surface
what happens to synovial fluid over time
replenished and absorbed
what colour is normal synovial fluid
clear and colourless
what is red synovial fluid caused by
haemorrhagic arthritis
what is yellow synovial fluid caused by
WBC
inflammatory or septic arthritis
where is articular cartilage
on the articular surfaces of bones at joints
function of articular cartilage
lubrication, reduce wear and tear
what happens when the breakdown of extracellular matrix > synthesis of extracellular matrix
osteoarthritis
what happens when the breakdown of extracellular matrix < synthesis of extracellular matrix
rheumatoid arthritis
what are the contents of extracellular matrix
water
type II collagen
proteoglycans
chondrocytes (make extracellular matrix)
where are muscle spindles
which direction do they run
muscle belly
parallel to muscle fibres
energy source for <4 secs eg weight lifting
ATP
energy source for <15 secs eg sprint
phosphocreatinine
energy source for <4mins
free circulating glucose
energy source for <77mins eg jog
glycogen stores
energy source for >4days
fat stores
