Lec 4

Question 1

what are the two types of ossification?

Answer 1

intramembranous ossification

endochondral ossification

Question 2

what type of ossification is long bones?

Answer 2

endochondral ossification

Question 3

what are the 5 steps of endochondral ossification

Answer 3

1. collar formation
2. cavitation
3. invasion of vascular supply
4. secondary ossification, medullary cavity, formation, elongation
5. Epiphyseal ossification

Question 4

How does a long bone increase in length whilst maintaining its shape?

Answer 4

by remodelling and appositional growth.

Question 5

Growth in width (appositional growth) and remodelling

Answer 5

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

Question 6

what makes bones grow?

Answer 6

hormones

Question 7

how does bone structure change with aging?

Answer 7

• everyone starts to lose bone mass between 30 and 40
• skeletal system becomes thinner and relatively weaker
• osteoporosis can occur in old age

Question 8

What is myogenisis?

Answer 8

Growth of muscles

Question 9

when does myogenisis happen

Answer 9

• increase in muscle cells (hyperplasia)
  mostly in last trimester - 4 moths of age
• becomes active during injury or stress

Question 10

what is hyperplasia?

Answer 10

• Increase number of cells in an area

Question 11

what is hypertrophy?

Answer 11

increase in muscle fibre size

Question 12

what are the three muscle fibre types?

Answer 12

Type I (slow twitch) - oxidative
Type IIa (fast twitch) - oxidative and glycolytic 
type IIx (fast twitch) - more glycolytic

Question 13

do males or females aged 20-30 have more type II fibres?

Answer 13

the males have a larger amount of type II fibres. although they are similar before puberty

Question 14

what happens with muscle mass with age

Answer 14

boys - increase until around 30 then slowly decline

girls - very steady and then drecreases

Question 15

when is the peak muscle

Answer 15

around ages 20-30

Question 16

how do you prevent muscle loss?

Answer 16

regular physical activity

Question 17

how does “learning” occur?

Answer 17

learning occurs by both addition and subtraction of synaptic processes

Question 18

when does synaptic density peak?

Answer 18

at age 2. this is when you are learning like a sponge

Question 19

why is infant reflexes so important?

Answer 19

because absent or abnormal reflexes in an infant may suggest significant central nervous system, nerve trunk, or peripheral problems

Question 20

what are some neurological conditions that effect children and elderly individuals

Answer 20

Autism, epilepsy, ADHD, mental retardation

Question 21

what are some diseases that elderly can get?

Answer 21

Alzheimers disease, parkinsons, multiple sclerosis

Question 22

how does multiple sclerosis occur?

Answer 22

demylenated sheaths = results in slow uncoordinated movement