Physiology Flashcards
name the 3 types of muscle
cardiac, smooth, skeletal
T/F: cardiac muscle is voluntary
fales..
innervated by the ANS and is involuntary
what are the 2 types of muscles that are striated
cardiac and skeletal
smooth muscle is…
unstriated and involuntary
T/F: skeletal muscle is voluntary
true, innervated by somatic nervous system
the excitation for cardiac muscle is?
Ca++ and extra cellular fluid
excitation for skeletal muscle is?
neuromuscular junction
how does strength of contraction mechanisms vary in cardiac and skeletal muscle?
cardiac: pre-load
skeletal: motor unit recruitment and summation
what is the NT for skeletal muscle?
Ach
breakdown a motor neurone complex?
1 alpha motor unti and parallel skeletal muscle fibres attached to skeleton via tendon
there are 2 types of skeletal muscle contractions; what are they?
isotonic- muscle tension constant, muscle length changes
isometric- muscle length constant, muscle tension develops
give an example for isotonic movement…
body movement or object movement
isometric contraction example…
posture
what are the 3 skeletal muscle fibres and what they’re best suited for?
T1: slow oxidative- long low aerobic
T2a- fast oxidative- long moderate aerobic
T2b- fast glycolytic- short anaerobic
what determines speed of contraction?
activity of myosin ATPase
T/F: 1 motor unit can contain multiple fibre types
F: can only contain 1 type
muscle organisation…
sarcomere>
sarcomere> myofibril> muscle fibre> muscle
what actually is a sarcomere and how it creates muscle tension?
arrangement of myosin and actin- actin slides on myosin
define a sarcomere…
the most basic contractile unit of muscle
fill in the gaps…
sarcomere is found between 2 _ ____ and have 4 zones- A and _ bands, _ zone and _-___.
found between 2 Z-lines and have 4 zones- A and I bands, H zone and M-line
what is the main power that causes actin over myosin sliding?
ATP which powers cross bridge formation and relaxation
what is the mineral component that drives cross-bridge formation?
Ca++
what is the action of Ca++ in cross-bridge formation?
bind to troponin pulling troponin-tropomyosin complex aside revealing cross-bridge site.
where is Ca++ released from and how
released from sarcoplasmic reticulum when AP spreads down t-tubules
where does ATP come from for AP production resulting in cross-bridge formation?
oxidative phosphorylation (aerobic) and glycolysis (anaerobic)
what determines grade of muscle contraction?
no of muscle fibres and tension developed by each contracting fibre (further determines by its length, freq of stimulation etc)
inc no of APs results in..
longer muscle twitch
what are 2 types of skeletal muscle activity?
excitatory/inhibitory and reflex
what is reason for reflex?
maintains optimal muscle resting length
what are the sensory receptors for stretch reflex and where are they located in the muscle?
muscle spindles found in belly of muscle
what are the 4 mechanisms of action for pain?
transduction, transmission, modulation, perception
pathway for nociceptors?
sensory afferents activated by noxious stimuli > 2nd order neurones which ascend spinal cord > reaches thalamus and synapses with 3rd order neurones > sensory cortex of brain
what are the 4 types of pain
nociceptive: provoked by intense nociceptor stimulation
inflammatory: immune system provoked
referred: caused by convergence of visceral and skin afferents at same spinal level
pathological
pathological pain is subdivided into…
neuropathic: damage to neural tissue
dysfunctional: no damage or infection
T/F: neuropathic pathological pain is localised, sharp pain
false: more general- burning, shooting, numbness
what are the 3 types of joints
synovial, fibrous and cartilaginous
what are synovial joints?
joints filled with synovial fluid and bones are united by a fibrous capsule
what are fibrous joints?
bones united by fibrous tissue
what are cartilaginous joints?
bones united by cartilage
T/F: synovial joints are the least mobile
False: fibrous are the least mobile > cartilaginous > synovial
how do joints support motion
stress distribution and synovial fluid (lubrication)
give 3 functions of synovial fluid?
lubricates joint, aids nutrition of articular cartilage and supplies chondrocytes with nutrients
T/F: synovial fluid is viscous
true: viscosity changes during movement- rapid movement= dec viscosity
what is the function of articular cartilage?
distributes contact pressure to subchondral bone
what is the structure of articular cartilage?
superficial zone middle zone deep zone calcified zone - made up of chondrocytes
which is the most common type of articular cartilage?
hyaline
which cartilage is sponge like and has extra-cellular membrane (water, T2 collagen, proteoglycans)?
hyaline
extracellular matrix is synthesised by which cells?
chondrocytes
what is responsible for the breakdown of extracellular matrix?
IL 1 & TNF-a
what 2 features can be used in a synovial tap to detect degradation?
- serum and synovial keratin sulphate
2. T2 collagen in synovial fluid
describe the innervation of muscle with reference to the NMJ…
a-motor neurones divide into unmyelinated branches to reach individual muscle fibres > then further divide into fn branches > these end at terminal bouton which synapses with muscle membrane (NMJ)
NMJ transmission…
- Ach synthesised in cytoplasm of bouton (choline + acetyl CoA)
- ach uptake into vesicles for storage
- Ca++ dependent release of Ach into synaptic cleft
- Ach binds to nicotinic Ach receptors opening gates causing Na+ influx and K+ efflux
- once certain no of gates opened end plate potential reached and triggers AP
- AP propagates over sarcolemma and down t-tubules causing Ca++ release switching on cross-bridge formation and contraction occurs
how does NMJ transmission terminate?
hydrolysis of Ach by acetylcholinesterase
