Endocrine Control Of Growth And Development

Question 1

What are somatomedians

Answer 1

Insulin like growth hormones - IGF’s

Prod in somatotrophs and cause sec of GH

Question 2

What are the thyroid hormones

Answer 2

T3 - triiodothyronine

T4 - tetrauidothyroinine

Question 3

What does calcitonin, vit d and PTH all functionally have in common

Answer 3

They help regulate the calcium balance in the body

Question 4

What are oestrogens and testosterone important for

Answer 4

Imp for the development of secondary sexual differentiations

Question 5

Explain GH secretion

Answer 5

In daily bursts not continuous
Initiated by GHRH
Secretion terminated by somatostatin

Question 6

Where is GHRH and somatostatin produced

Answer 6

The hypothalamus

Question 7

What is diurnal rhythm

Answer 7

Sleep/wake pattern

Peak sec highest in morning and decreases though the day

Question 8

What happens if GH is injected to a hypophysectomised animal

Answer 8

Stimulation of bone growth
Stim of protein syn
Stim RBC prod
Anti insulin effect - increase hepatic glucose, promote lipolysis and decreased glucose uptake

Question 9

What are the effects of GH

Answer 9

Growth by increasing protein syn in tissues it increase num and size of cells
In bone it promotes IGF1 which bone growth at epiphyseal plates before close off

Has metabolic actions

• increase net syn of protein
• decreases glucose uptake
• increase lipolysis

Question 10

What are the stimulants for GH secretion

Answer 10

Deficiency of energy substrate 
Hypoglycaemia 
Exercise and fasting 
Increases in blood amino acids arg or leu
Glucagon 
Stress
Deep sleep

Question 11

What are the inhabitants of GH

Answer 11

Rapid eye movement sleep 
Hyperglycaemia 
Cortisol 
Free fatty acids 
GH 
Hypothyroidism 
Ageing

Question 12

What does GH do to carbohydrates

Answer 12

Increases blood glucose
Decreases peripheral insulin sensitivity
Increases hepatic glucose output

Question 13

What does GH do to proteins

Answer 13

Increase the tissue amino acid uptake
Increase incorporation into proteins
Decrease urea production

Question 14

What does gh do to lipids

Answer 14

Lipolysis - activates hormone sensitive lipase (ligase stimulated by adrenaline and GH) yield FA’s

Question 15

What does GH do to IGF’s

Answer 15

Stimulates production of IGF’s
Stimulates growth
Is mitigenic ( stim grow in soft tissues)

Question 16

What produces IGF-1

Answer 16

The liver

Question 17

What causes the production of IGF-1

Answer 17

The sce of GH

Question 18

What does IGF-1 do

Answer 18

Stimulate the bone growth and cell proliferation leading to soft tissue growth

Question 19

What can sometimes happening dwarfism

Answer 19

That GH is norm,a but IGF-1 hormone subnormal

Question 20

What happens when there is an adenoma in the anterior pituitary in children and adults

Answer 20

Children - leads to gigantism - excess GH to epiphyseal plates deal - long bone prod

Adult - acromegaly - thickening of bones coarsened facial features and thickend fingers hands and feet

Question 21

What 3 hormones does the thyroid gland produces

Answer 21

Triiodothyronine
Tetraiodothyronine
Calcitonin

Question 22

What mech regs t3/t4

Answer 22

Negative feedback loop

Question 23

How are t3 and t4 ttansported in the blood

Answer 23

Bound to thyroxine- binding globulin plasma protein (TBG)

Question 24

What is the structure of the thyroid gland

Answer 24

Follicular cells - spheres on the outer layer

Filled with colloid - extracellular storage for th
Tyrosine containing thyroglobulin filed spheres enclosed by follicular cells

Question 25

What is required for new thyroid hormones and how are they obtained

Answer 25

Iodine and tyrosine and taken up by follicle cells

Question 26

How are new thyroid hormones prod

Answer 26

Iodine and tyrosine taken up In colloid iodine attach to tyrosine residue to form MIT and DIT If DIT+DIT= T4 Or. DIT+ MIT = T3 Sited in colloid until needed

Question 27

What does t3 and t4 do

Answer 27

Promote accelerate metabolism Increase carbohydrate fat and protein turnover Increase oxygen consumption and increased heat production Imp during Dev if hypothyroidism in child = CRETIN

Question 28

What is sympathomimetic action

Answer 28

Increases responsiveness to catecholamines adrenaline and noradrenaline by increasing number of adrenal receptors

Question 29

What is hyperthyroidism

Answer 29

``` Lead to heat intolerance Nervousness Insomnia Weight loss High nitrogen exertion ```

Question 30

What is hypothyroidism

Answer 30

Lead to cold intol Excess sleep Muscular fatigue Weight gain

Question 31

What is the basal metabolic rate

Answer 31

Amount of energy con husked during a testing individual so energy r reunited to just be in living state (energy for brain activity, pump blood and cellular processes)

Question 32

What is the primary regulatory hormone of BMR

Answer 32

Thyroid hormone

Question 33

What is the condition hypothyroidism in adults

Answer 33

Myoxedema

Question 34

What is goitre

Answer 34

Swell of thyroid gland Iodine deficiency - red t3/t4 promote excessive TSH secretion a nd growth of thyroid Graves' disease - TSI promote thyroid growth Excess TSH form ant pit

Question 35

What is when there is no goitre

Answer 35

Hypothyroidism secondary to hypothalamus or ant pit failure (thyroid is not excessively stimulated) Overactive thyroid TSH suppressed by excessive t3/4

Question 36

What are testosterones actions

Answer 36

In fetal Dev imp for reproductive organs | During puberty stim bone growth and SECINDARY sexual characteristic

Question 37

What does estradiol

Answer 37

``` Oestrogen Stimulates growth of uterus Imp for follicular growth Stim bone growth Delay bone loss during menopause ```

Question 38

Where is GH prod

Answer 38

Anterior pituitary