1. Thymus, Pineal, Thyroid, Parathyroids

2. The Thymus Location: upper thorax, posterior to sternum Description:
Large in infants/children
Decreases in size throughout adulthood
Made of fibrous connective tissue and fat

3. Thymosin Main hormone of the thymus
Essential for development of T-cells (a group of white blood cells) and immune response

4. The Pineal Gland Location: brain (roof of 3rd ventricle) Description:
Small, cone-shaped gland
Not a lot is known about it beyond the secretion of melatonin

5. Melatonin Main hormone of the pineal Peak levels at night- drowsiness
Lowest levels around noon
In animals, also helps regulate mating behavior and rhythms

6. Seasonal Affective Disorder
Type of depression
Related to changes in seasons
May occur due to drops in serotonin (reduced sunlight) and affect melatonin (sleep patterns, mood)
Begins and ends about the same time each year (fall/winter)
Saps energy, moodiness
Treatment: light therapy, psychotherapy, medication

7. Summary- be ready to answer! Match the location of each gland.
Hypothalamus
Above pituitary
Pituitary
3rd ventricle
Thymus
Sella turcica
Pineal
Thorax

8. Summary- be ready to answer! Match the function of each hormone.LH
Melatonin
OXT
PRL
Thymosin
TSH
Mammary gland development and lactation
Plays a major part in the immune response
Plays a role in sleep-wake cycles
Tells the thyroid to make thyroid hormones
Induces ovulation and the release of other hormones
For bonding, promoting labor, and milk ejection

9. Summary- be ready to answer! Match the function of each hormone.
ACTH
ADH
FSH GH
GH-IH
ICSH
Inhibits urine production
Prevents secretion of growth hormone
In males, stimulates androgen production
Makes adrenal cortices release hormones
In females, induces follicle & egg development
Maintenance and repair of body tissues

10. Thyroid Gland Location: in the neck Description:
Base of throat, inferior to Adam’s apple
Description:
Two lobes joined by an isthmus
Composed of follicles
Regulates metabolism
Influences mental & physical abilities
For normal growth (along with GH)
Requires iodine

11. Thyroid Hormone
Controls the rate at which glucose is oxidized (“burned”) and converted into heat and energy
Every cell in the body is a target cell

12. Thyroid Hormone 2 similar, iodine-containing hormones
Thyroxine (T4)- major thyroid hormone
Triiodothyronine (T3)- most formed at target tissues when T4 is converted to T3
Made and stored in follicles
Constructed from two tyrosine amino acids linked together plus bound iodine (T3=3; T4=4)

13. Calcitonin
Decreases blood calcium levels (deposits the calcium in bones)
Is the antagonist of parathyroid hormone
Made by parafollicular cells (connective tissues between follicles)

14. Abnormal Growths Nodule- any abnormal growth that forms a lump
Goiter- enlargement of the thyroid
Results from iodine deficiency
Can also result from overproduction of hormones

15. Goiter

16. CRETINISM: hyposecretion of thyroxine in early childhood
Lack of physical growth
Lack of mental development
If caught early, hormone replacement can prevent mental retardation and some other symptoms

17. MYXEDEMA: hyposecretion of thyroxine as adult
Physical and mental sluggishness
Puffiness of the face, obesity
Fatigue, poor muscle tone, low body temperature
Treat with oral thyroxine

18. HASHIMOTO’S DISEASE: autoimmune hypothyroidism
Autoimmune thyroiditis- immune system attacks the thyroid
May result in goiter
Treat with hormone replacement, surgery

19. HYPERTHYROIDISM Overactive thyroid Metabolism increases, weight loss
Rapid pulse, tremors, sweating, anxiety
Treat with thyroid-blocking drugs, radioactive iodine to kill thyroid cells, or surgical removal of part of the thyroid

20. HYPERTHYROIDISM GRAVE’S DISEASE: autoimmune hyperthyroidism
Symptoms of hyperthyroidism
Thyroid enlarges
Eyes may bulge or protrude anteriorly (exophthalmos)

21. THYROID CANCER Papillary: most common (70-80% of cases).
Usually diagnosed age 30-50
Occurs 3x more often in women
Least aggressive type
May spread, but usually not beyond the neck

22. THYROID CANCER Follicular: 10-15% of cases Women 3x more
Usually diagnosed between ages 40-60
Cancer cells may invade blood vessels and travel
Can be more aggressive in older patients

23. THYROID CANCER Medullary: 5-10% of all cancer cases
Tends to run in families
Often diagnosed ages 40-50
Males/females affected equally
Develops in parafollicular cells; elevated calcitonin levels can indicate cancer

24. THYROID CANCER Anaplastic (rare- fewer than 5% of all cases)
Generally in older people (over the age 65)
Females affected more often than males
Aggressive and invasive
Very difficult to treat

25. Thyroid Neck Check
(start at 0:29)

26. Parathyroid Glands
Location: Posterior surface of thyroid gland (embedded)
Description:
Four tiny masses of glandular tissue
Regulate blood calcium homeostasis

27. Parathyroid Hormone (PTH) or parathormone
Released when blood calcium (Ca+2) levels drop
Major target tissue: bone
Stimulates osteoclasts to break down bone matrix and release Ca+2 into blood
Also stimulates kidneys and intestine to absorb more Ca+2

28. Parathyroid Hormone Diseases
TETANY: uncontrollable muscle spasms due to hypocalcemia (makes neurons irritable and overactive)
May be fatal

29. Parathyroid Hormone Diseases
Hyperparathyroidism
If too much calcium is removed and put in blood, bones become fragile
Kidneys excrete calcium; too much can lead to kidney stones
If severe, bones undergo massive destruction. Likely to experience spontaneous fractures.

30. Be ready to answer!
Why is iodine important for proper thyroid function?
Some thyroid diseases are autoimmune. What does “autoimmune” mean?
Which hormone is hypercalcemic (increases blood calcium levels)? Which gland makes it?
Which hormone is hypocalcemic (decreases blood calcium levels)? Which gland makes it?
How are the thyroid and parathyroids linked anatomically?