Lec 4 Flashcards
what are the two types of ossification?
intramembranous ossification
endochondral ossification
what type of ossification is long bones?
endochondral ossification
what are the 5 steps of endochondral ossification
- collar formation
- cavitation
- invasion of vascular supply
- secondary ossification, medullary cavity, formation, elongation
- Epiphyseal ossification
How does a long bone increase in length whilst maintaining its shape?
by remodelling and appositional growth.
Growth in width (appositional growth) and remodelling
Growth - cartilage grows on top of bone then on inside the cartilage is replaced by bone.
remodelling - bone is resorbed around the head of the long bone. then it is deposited on the outside of the shaft. then bone is resorbed on inside of shaft
what makes bones grow?
hormones
how does bone structure change with aging?
- everyone starts to lose bone mass between 30 and 40
- skeletal system becomes thinner and relatively weaker
- osteoporosis can occur in old age
What is myogenisis?
Growth of muscles
when does myogenisis happen
- increase in muscle cells (hyperplasia)
mostly in last trimester - 4 moths of age - becomes active during injury or stress
what is hyperplasia?
- Increase number of cells in an area
what is hypertrophy?
increase in muscle fibre size
what are the three muscle fibre types?
Type I (slow twitch) - oxidative Type IIa (fast twitch) - oxidative and glycolytic type IIx (fast twitch) - more glycolytic
do males or females aged 20-30 have more type II fibres?
the males have a larger amount of type II fibres. although they are similar before puberty
what happens with muscle mass with age
boys - increase until around 30 then slowly decline
girls - very steady and then drecreases
when is the peak muscle
around ages 20-30
how do you prevent muscle loss?
regular physical activity
how does “learning” occur?
learning occurs by both addition and subtraction of synaptic processes
when does synaptic density peak?
at age 2. this is when you are learning like a sponge
why is infant reflexes so important?
because absent or abnormal reflexes in an infant may suggest significant central nervous system, nerve trunk, or peripheral problems
what are some neurological conditions that effect children and elderly individuals
Autism, epilepsy, ADHD, mental retardation
what are some diseases that elderly can get?
Alzheimers disease, parkinsons, multiple sclerosis
how does multiple sclerosis occur?
demylenated sheaths = results in slow uncoordinated movement
