muscles and joint Flashcards
types of muscle
smooth
striated
cardiact
describe smooth
spindle shaped cells
centrally placed nuclei
no pattern
2 layers - longitudinal and circular layer
desribe cardiac muscle
short branched fibres
joined by intercalated dics
centrally placed nuclei
short contraction duration
what surrounds cardiac muscle
white parts which contain glycogen stores
what are in the intercalated disks
desmosomes
gap junctions
features of cariomyocutes
involuntary
pulsate without nervous stimulation
controlled by ANS (cardiac plexus)
where is smooth muscle found
visceral muscles and organs
describe skeetla/sttriated mscel
nucleus at the top
arranged in regular arrangement of contractile proteins
control of somatic NS
multinucleate, myoblast cells fuse
what are the layers which surround msucle
endomysium
perimyosium
epimysium
what surrounds the bundles of facials
epimysium
what surrounds facicles
perimysium
what surrounds individual fibres
endomysium
what do myofilaments contain
actin
myosin
describe myosin
globular heads
shafts wrapped around each other
describe actin
2 beaded chains which cross link
G actin to form F actin (polymer)
what happens during contraction
myosin pulls inwards
shortens sarcomere
myosin heads are hinged
what are the bands/lines
H band - myosin only A band - myosin and actin I band - only actin Z line - disk connection between sarcomeres M line - attachment site for myosin
types of skeletal muscle
1 - slow
2A - intermediate
2B - fast
describe type 1 fibres
slow twitch used in posture los of mitochondria and capillaries red appearance (myoglobin) areoci metablosims
desrbe type 2B fibres
fast twitch white appearance (lack of myoglobin) anaerobic conditions (glycolytic) fatigue easily powerful movements
descrie type 2A fibres
intermmediate
little of myoglobin
contract rapidly
oxidative and glycolytic metabolism
what innervates motor units
single motor neurone
what determines the amount of control of muscle
motor ratio
how many muscle fibres the neurone innervates
what is graded muscle contraction
recruits a certian amount of motor units depending on function and load
what control muscles
muscle spindles
what are the sensory receptors in. muscle
extrafusal and intrafusal muscle fibres
descibre intrafusal fibres
send proprioceptive info to SC and cerebellum
innervation from gamma neurones
describe extrafusal fibres
bulk of muscle
motor supply from alpha motor neurones inverted by defending motor pathways and sensory neurones from muscle spindsles
what determine regulation of amount of muscle contraction
density of muscle spindles
describe reflexes
CNS not involved
acts on ligament, muscle spindles stretched
signal to SC
motor neurone srecive impulses causing contractin
where are synovial joints formed
between two or more bones
forms of synovial joint
partially mobile
fully mobile
what is found in a synovial joint
articular cartilage synovial cavity synovial joint reinforcing ligament articular capsule
articular cartialge
covers inner C (i.e. articualting surfaces) for smooth movement
absorb compression
takes up synovial fluid during movment
synovial cavity
contains synovial fluid
lubrication
synovial fluid
viscous
contains phagocytic cells
secreted by synovial membrane
articular capsule
connective tissue
double layers (synovial membrane, outer fibrous capsule)
lines all surfaces without articular cartilage
reinforcing ligament
strengthen joint
intrinsic, extrinsic, intracapsular
sensory innervation in oints
Golgi tendon organs (proprioception)
free nerve endings (pain)
what is trismus
excess tone of muscle
