Lecture 30 Flashcards
Developing Control of Ourselves
what are the mechanical functions of bones
- structural framework
- stable foundation for posture and movement
- protection of important organs
what are the non mechanical functions of bones
- reservoir for mineral deposition, blood regulation of calcium and phosphorus
- supports haematopoiesis
- defends against acidosis
- absorbs / captures potentially toxic minerals
when does bone formation begin
prenatal = 5 weeks
what changes to bone occur in infancy + childhood + adolescence
mechanical stimulation of epiphyseal plates affects long bone growth
when does rapid bone growth occur and what is important that needs to happen
1-4 years, puberty
- important that forces are applied against the bones
when does peak height velocity occur
~12.5 (males)
~13.5 (females)
what age do epiphyseal plates close
~25 years
what age is maximal bone mass
~30 years
what is osteopenia
components of bone fail to develop, loss of bone mineral density = weaker bones
what is osteomalacia
related to calcium and phosphate deficiencies
what is osteoporosis
decreased bone formation of new bone = brittle bones
what happens to the walls and width of bones as we age
walls become thinner and bones become a bit wider
what happens to the muscular system at ~5 weeks prenatal
myotubes formed
when are the first muscle fibres formed
~20 weeks
at birth what % of body mass is muscle
~25%
when do muscles mature but what does this mean
muscles mature in childhood, but this doesn’t mean they can behave physiologically like adult muscles can
at 10 years old muscle relaxation occurs, what does this mean
speed reaches adult levels, likely to improve contraction speed
what is sarcopenia
loss of muscle mass
in their 70s, what is the prevalence of men and women with sarcopenia
19% men and 34% women
in their 80s, what is the prevalence of men and women with sarcopenia
55% men and 52% women
inside muscles, what changes in the elderly
change in muscle protein synthesis
change in contractile proteins
at 16 the average male is stronger than what
stronger than a very strong female
at the age of 30 what % muscle mass occurs per decade
5%
what type of strength is maintained better in old age
eccentric strength is maintained better than concentric strength
what is the saying of endurance as we age
use it or lose it
what are 3 adaptations to central and peripheral nervous systems with age
- neural plasticity
- neuron cell death
- response to injury
what is neuroplasticity
ability of nervous system in particular the cortico-cerebellar system to change
what is experience dependent plasticity
ability to reorganise its structure and function to sensory input, learning and environmental experiences
what is experience expectant plasticity
given typically experience in daily activities we expect the brain will rewire its self accordingly
why does neuron cell death occur
there is overproduction of neurons to ensure sufficient number to complete “wiring”, so some culled
what is apoptosis
programmed cell death
what is axon pruning
trimming of extraneous axon connections, occurs without damage to cells
when does axon pruning peak
around puberty
if there is an injury to the PNS can it regenerate
yes, given ideal conditions can happen around 30mm month
if there is an injury to the CNS can it regenerate
no
when is the inital formation of CNS
~3 weeks
when do synapse formations begin and myelination
~6-7 weeks
at birth the brain is what fraction of their weight
1/4
at 6 months the brain weight has what
doubled
at 13 the brain is …
morphologically mature but not physically mature
when is peak myelination
~50 years
what are the reductions to the basal ganglia like with age
no significant reductions
what does the vestibular sense provide
provides information about the bodies position relative to gravity
most important sense
vision
three forms of sensory intergration
intrasensory integration
intersensory integration
sensorimotor integration
what is another word for proprioception
kinasethesis
when does adult like depth perception occur
aged 12
