The Thyroid And Parathyroid

Question 1

What chemical is necessary through diet to produce hormones?

Answer 1

Iodine or else goiter

Question 2

How many parathyroid glands do mammals have?

Answer 2

4, 2 on each side

Question 3

What 2 hormones does the thyroid produce to regulate metabolism?

Answer 3

Through the production of 2 hormones:

1. Thyroxine (T4)
   • accounts for majority of thyroid secretions
   •made in thyroid from tyrosine (amino acid) and 4 iodines
2. Triiodothyronine (T3)
   • more potent than thyroxine but not produced in the same quantity
   •also made in thyroid from tyrosine and 3 iodines

Question 4

How does the thyroid gland regulate metabolism?

Answer 4

-T3 and T4 cause people to undergo cellular respiration at faster rate (generates ATP and heat)

Question 5

release of T3 and T4 is controlled by homeostatic control system

Answer 5

Sensor:

• drop in metabolism detected by receptors in hypothalamus
• the hypothalamus releases thyroid releasing hormone (TRH)

Integrator:
-TRH triggers pituitary gland

Effector:

• pituitary gland releases thyroid stimulating hormone (TSH)
• TSH stimulates release of T3 and T4 by thyroid (increasing metabolism)
• T3 and T4 are also released for stress or cold

Question 6

What does calcium do for the body?

Answer 6

-Ca2+ is available for enzyme activation, conduction if nerve signals, muscle contraction, blood clotting, and other uses*

• -muscle contractions
• send/ receive nerve signals
• activate enzymes
• increase bone/teeth strength
• helps increase absorption of other nutrients
• critical in disease prevention
• most abundant mineral in body

Question 7

How does the thyroid regulate [calcium] through the production of calcitonin?

Answer 7

• lowers the [calcium] by decreasing activity of osteoclasts (break down bone) while stimulating the activity of osteoblasts (build up bone)
• also decrease reabsorption of calcium in the nephrons

Question 8

How do the parathyroid glands regulate the [calcium] in the blood through the production of parathyroid hormone?

Answer 8

-raises the [calcium] by increasing activity of osteoclasts and increasing reabsorption of calcium in nephrons

Underproduction: results in poor nerve and muscle function
Overproduction: leads to osteoporosis