Groeth And Ageing

Question 1

What does growth involve

Answer 1

Hyperplasia
Hypertrophy

Question 2

What is hyperplasia

Answer 2

Increase in cell numbers

Question 3

What is hypertrophy

Answer 3

Increase in cell size

Question 4

Give examples of some cells that can regenerate

Answer 4

Liver, skin, blood cells

Question 5

Give some examples of cells that cannot regenerate

Answer 5

Neurons

Question 6

What is growth effected by

Answer 6

• genes, heredity
• enviroment

Question 7

What is included in enviroment

Answer 7

• nutrition
• disease
• growth factors, such as hormones

Question 8

What are hormones that influence growth

Answer 8

• thyroid hormones
• growth hormones
• sex hormones

Question 9

Describe thyroid hormones

Answer 9

• essential for normal development and growth
• essential for protein synthesis in brain of fetus and infant
• required for normal development of neurons
• necessary for childhood growth
• indirect, rather than direct effects on growth

Facilitates actions of growth hormones and systematic nervous system

Question 10

What is hypothyroidism

Answer 10

• overactive thyroid
• fetal/ neonate hypothyroidism
• sparse hair
• large tongue
• permanent mental impairments

Question 11

How does hypothyroidism effect the tooth eruption

Answer 11

Delayed tooth eruption

Question 12

What is the function of growth hormone

Answer 12

Has metabolic and growth promoting actions

Question 13

What are the metabolic actions of growth hormone

Answer 13

• increase in blood glucose levels
• decrease in glucose uptake by cells
• increase in lipolysis, making fatty acids available for energy production
• facilitates uptake of amino acids for protein synthesis

Question 14

Why is orthodontic treatment carried out under the age of 12

Answer 14

Because the face is still growing

Question 15

When does the brain finish growing

Answer 15

About 8 years old

Question 16

What is the effect of insulin like growth factor

Answer 16

Cartilage proliferation in long bones, until epiphyses (growth centres) close

Question 17

What are examples of sex hormones

Answer 17

Testosterone and oestrogen

Question 18

What are sex hormones responsible for

Answer 18

Responsible for pubertal growth spurt

Question 19

What are the effects of the sex hormones mediated by

Answer 19

Mediated by increased secretion of GH and IGF-1

Question 20

What are the effects of testosterone

Answer 20

Anabolic effects on protein synthesis, increasing muscle bulk

Is the anabolic steroid

Question 21

What is the effect of sex hormones on bones

Answer 21

Stimulates bone growth, but accelerate the closure of epiphyseal growth plates

Question 22

What can hypothyroid cause in children

Answer 22

Dwarfism, infant proportions, overweight

Question 23

What does a hypopituitary dysfunction cause in an 8 year old boy

Answer 23

Dwarfism, slimmer

Question 24

What are some other hormones that can affect growth

Answer 24

• insulin
• corticosteroids
• vitamin D
• parathyroid hormone

Question 25

Describe how insulin contributes to growth

Answer 25

- promoting foetal growth - promoting post natal growth by stimulating IGF-1 - facilitating protein synthesis (by making glucose available for energy production)

Question 26

When present at higher than normal levels cortisol can…

Answer 26

Inhibit growth

Question 27

What are the functions of cortisol in growth

Answer 27

- stimulates protein catabolism - supresses bone growth and promotes Reabsorption Raised levels of cortisol in stress and illness account for the growth retarding effects of childhood illness

Question 28

How does vitamin D and PTH contribute to growth

Answer 28

Vitamin D is responsible for Calcium absorption in the gut PTH raises plasma calcium levels They are responsible for ensuring adequate amounts of calcium and phosphate for bone formation

Question 29

Excess growth hormone in childhood does what

Answer 29

Accelerates normal growth - gigantism

Question 30

What happens when there is excess growth hormone in adults

Answer 30

- appositional growth in the extremities - hands and feet and jaw increase in bulk, acromegaly

Question 31

What is acromegaly

Answer 31

Excess growth hormone leads to hands, feet and jaw increase in bulk

Question 32

What is achondroplasia

Answer 32

- defective cartilage growth - affects long bones and cartilage growth centres eg spheno-occipital synchondrosis in cranial base

Question 33

What is diastema

Answer 33

Spaces in between teeth Food may get stuck

Question 34

What can patients that have acromegaly have

Answer 34

Increased risk of tumor of the pituitary gland

Question 35

What does ageing involve

Answer 35

Gradual detioration of all parts of the body Complicated by disease

Question 36

What does an individuals life span depend on

Answer 36

- genetics - enviroment - no evolutionary advantage in old age

Question 37

What is included in the enviroment pod longevity

Answer 37

- good nutrition - lifestyle - absence of disease

Question 38

Describe cellular ageing

Answer 38

Decline in the ability of cells to divide over time Accumulation of damage as the cells divide in old age

Question 39

Give some examples of apoptosis

Answer 39

- in development, tooth germ, nervous system - to replace worn out cells - to destroy tumour cells