Endocrine System & Hormones

Question 1

Define homeostasis

Answer 1

the condition of equilibrium (balance) in the body’s internal environment

Question 2

What are 2 examples of positive feedback loops?

Answer 2

Blood clotting
Contractions

Explain.

Question 3

What are 2 examples of negative feedback loops?

Answer 3

high body temperature
low body temp

Explain.

Question 4

What is a hormone?

Answer 4

mediator molecules (chemical signals) that are released by an endocrine gland, too regulate activities in cells in other parts of the body

Question 5

What are 3 types of endocrine glands?

Answer 5

Pituitary, thyroid, parathyroid

Question 6

What are 3 types of endocrine tissues/organs?

Answer 6

hypothalamus, thymus, kidneys

Question 7

What is considered the “master gland”?

Answer 7

hypothalamus

Question 8

What are 3 functions of hormones?

Answer 8

Helps regulate composition and volume of interstitial fluid

Control growth and development

Helps regulate metabolism and energy balance

Question 9

What will hormones bind to?

Answer 9

Specific receptors on specific target cells/tissues

Question 10

What are the two types of hormones (in terms of travel)?

Answer 10

Circulating and local

Question 11

How do lipid soluable hormones illicit a response?

Answer 11

Diffuse directly into cell and bind to receptors on the nucleus

(need protein through blood stream)

Question 12

How do water soluable hormones illicit a response?

Answer 12

Cannot diffuse directly into a cell, signal 2nd messenger response

(independent through blood stream)

Question 13

Responsiveness of target cell depends on what 3 things?

Answer 13

• Concentration of hormone in the blood (increased = increased response of target cell)
• Abundance of receptors on a cell (increased = increased response of target cell)
• Influence of other hormones

Question 14

What is synergism?

Answer 14

the combined effect of 2 hormones is greater than each on its own

Question 15

What are the two pituitary glands?

Answer 15

Anterior and posterior

Question 16

Which pituitary gland releases hormones that regulate body function?

Answer 16

Anterior pituitary gland

Question 17

What are the two thyroid hormones?

Answer 17

T3 and T4

Question 18

What is the role of thyroid hormones?

Answer 18

• Sets basal metabolic rate (oxygen consumption, energy expedition at resting state)
• Metabolism (synthesis of carbs, proteins, fats)
• Heat production (increased metabolic activity, leads to increased heat)
• Regulates tissue growth and development (CNS)
• Cardiovascular system (effects on heart rate and blood pressure)

Question 19

What is hyperthyroidism? What is the opposite?

Answer 19

overactivity of thyroid gland causing increased thyroid hormone secretion

Hypothyroidism - underactivity of thyroid gland causing decreased thyroid hormone secretion

Question 20

Explain the negative feedback control of thyroid hormone release

Answer 20

Low blood levels of T3/T4 or metabolic rate occur in blood and are detected
Hypothalamus releases TRH (Thyrotropin-releasing hormone)
TRH travels from hypothalamus down hypophyseal portal veins to anterior pituitary glands
Anterior pituitary glands are stimulated to release TSH (thyroid-stimulating hormone)
TSH enters blood stream and travels to thyroid gland to stimulate thyroid follicles
Follicles are stimulated and release T3 and T4 into blood stream
T3 inhibits TSH and TRH, therefore stops stimulus from producing thyroid hormone