1. Endocrine System
SBI4U
Nov 9

3. The Pituitary Gland: Master Gland Posterior Anterior

4. Anterior vs posterior pituitary lobe
Posterior (back lobe) : stores & releases hormones.
Anterior (front lobe) : produces hormones.

5. Thyroid Gland Controlled by TSH T3+ T4 Calcitonin In liver T4 T3+I to
become active.

7. Thyroid disorders
Goiter
Graves’ disease

8. Parathyroid Gland 4 small glands Secrete PTH Need vitamin D for
Calcium reabsorption.
N.B: 2 anatagonistic
hormones control
Ca 2+ levels in blood

9. Regulation of calcium levels through negative feedback control

11. Ricket Disease
-Vitamin D deficiency
-Most frequent childhood disease.

12. Acitvity- Questions

13. Hormone
Stimulus
Secreted by
Target
Effect
TSH
nutrition
Anterior pituitary
Thyroid gland
Stimulates the secretion of T3 and T4
ACTH
stress
Anterior pituitary gland
Adrenal cortex
Glucocoticoids secretion
STH
FSH

14. GH
puberty
Anterior pituitary gland
Growth
growth/mitosis LH
folicle
ovulation
PRL
suckling
Mammary gland
Lactation
Oxytocin
Uterine contractions

15. ADH
Insulin
Amylin
A decrease in blood glucose
Epinephrine
Thyroxine
Triiodothyroxine

16. Increase in blood calcium
PTH
Aldosterone
TRH
spermatogenesis
estrogen
progesterone
Renin

17. Q2- Why do some people eat lots and gain no weight?

18. Answer:
The lower the thyroxine is released the slower blood sugar is used therefore the faster fat stores build up. These individuals secrete high levels of thyroxine which oxidize sugars and other nutrients at a faster rate.
Food 60 % heat (these individuals feel very warm)
40% ATP production

19. Q3- As a person ages growth hormone production decreases
Q3- As a person ages growth hormone production decreases. Explain the link between growth hormone production and aging?

20. As a person ages growth hormone (GH) production begins to decline therefore cellular and protein replacement is compromised.GH increases cell size in muscle cells & connective tissues by promoting protein synthesis and inhibiting protein degradation. As you age protein is often replaced by fat causing changes in body’s shape.

21. Q4. A nuclear accident in Chernobyl caused the release of radioactive wastes in air. The effect of the problem is still unknown but the effect on children has been the most extreme. One of the most radioactive materials released was Iodine- 131 which causes inflammation and can lead to cancer. Draw a feedback loop that shows how thyroxine levels might be affected.

22. Increase in Iodine-131 levels-thyroid damagedthyroid cannot detect TSH levels T3+T4 production reduced low T4 levels do not turn off hypothalamus therefore increased production of TRHhypothalamus increases production of TRH anterior pituitary produces TSH thyroid cannot detect levels of TSH.