10.2 Endocrine Glands

Question 1

Thyroid and Parathyroid Gland Hormones

Answer 1

• The thyroid gland is a
  butterfly-shaped
  gland located in front
  of the throat in all
  vertebrates.
• Thyroid hormones
  have a wide range of
  effects

Question 2

Thyroid hormones stimulate

Answer 2

Growth,
development, maturation, and metabolism
in all vertebrates
- Increase sensitivity of body cells to the
effects of epinephrine and norepinephrine
- Increased thyroid hormones increases
metamorphosis of tadpoles, and seasonal
moulting in some birds and mammals

Question 3

Thyroid Hormones

Answer 3

• Primary thyroid hormone is thyroxine (T4)
• Dietary Iodine is necessary to produce
  hormone; not enough iodine in diet results
  in overstimulated thyroid gland (goiter)
• T4 is a lipid soluble hormone

Question 4

Calcitonin

Answer 4

• Thyroid secretes calcitonin, which lowers
  the level of Ca2+ in the blood (prevents
  release from bones)
• Secreted when blood calcium rises above
  normal range
• Inhibited when blood calcium falls below
  normal range
• Hormone can also be synthesized in the
  lungs and intestines

Question 5

Parathyroid Hormone (PTH)

Answer 5

• Secreted when blood calcium levels fall
• Stimulates bone cells to dissolve tissue,
  releasing calcium and phosphate levels
• Calcium is used in the body for enzyme
  activation, nerve impulses, muscle contractions, blood clotting, and other uses

Question 6

Adrenal Medulla

Answer 6

Produces two hormones:
Epinephrine (Adrenaline)
- Accelerates heart rate and body reactions
Norepinephrine (Noradrenalin)
- Increased heart rate and blood sugar

Stimulated by NERVES to secrete hormones
in times of stress

Question 6

Adrenal Glands

Answer 6

• The adrenal glands are located above each
  kidney
• Each gland is made up of two glands encased
  in one shell
• The inner gland, the ADRENAL MEDULLA is
  surrounded by an outer casing called the
  ADRENAL CORTEX

Question 7

Adrenal Cortex: Produces Three different types of Hormones:

Answer 7

GLUCOCORTICOIDS, MINERALOCORTICOIDS, SEX HORMONES

Question 8

GLUCOCORTICOIDS –

Answer 8

Helps the body meet the demands
of continued stress
- (Ex. CORTISOL = increases amino acids in the bloodstream
to be converted to sugar)

Question 9

MINERALOCORTICOIDS –

Answer 9

Regulates salt/water balance
(Increases blood volume/pressure)
- (Ex. ALDOSTERONE = helps increase water reabsorption by
increasing Na+ retention)

Question 10

SEX HORMONES -

Answer 10

Helps to regulate sex organs

Question 11

Pineal Gland

Answer 11

• Located in the brain
• Secretes melatonin, which maintains biorhythms
• Light inhibits melatonin secretion, darkness activates it