Biology 30 - Endocrine system

Question 1

What does the endocrine system do?

Answer 1

The endocrine system works with the nervous system to coordinate and direct the activity of the body’s cells to maintain homeostasis.

Question 2

What are endocrine glands?

Answer 2

Endocrine glands produce hormones (proteins) and secrete them into the bloodstream.

Question 3

What are hormones?

Answer 3

Hormones are chemical messengers produced by endocrine glands, secreted into the bloodstream, and travel via the circulatory system to target cells.

Question 4

What are target cells?

Answer 4

Target cells have specific protein receptors that allow them to respond to hormones by triggering a metabolic/physiological effect.

Question 5

What is negative feedback in the endocrine system?

Answer 5

Negative feedback occurs when the accumulation of a biochemical switches off hormone synthesis to maintain homeostasis.

Question 6

What is positive feedback in the endocrine system?

Answer 6

Positive feedback occurs when a hormone’s effect stimulates its further secretion, enhancing the response (common in pregnancy, childbirth, and lactation).

Question 7

What hormones does the hypothalamus produce?

Answer 7

The hypothalamus produces releasing hormones that control the anterior pituitary, along with ADH and oxytocin, which are stored in the posterior pituitary.

Question 8

What does the posterior pituitary gland store and secrete?

Answer 8

It stores and secretes ADH and oxytocin, produced by the hypothalamus.

Question 9

What is the function of ADH?

Answer 9

ADH promotes water retention by the kidneys, producing more concentrated urine and increasing blood pressure.

Question 10

What does oxytocin do?

Answer 10

Oxytocin triggers milk ejection and stimulates labor contractions during childbirth through positive feedback.

Question 11

What is the function of growth hormone (GH)?

Answer 11

GH stimulates growth, especially in bones and muscles, and increases metabolism. It is important for normal development in children.

Question 12

What are GH disorders?

Answer 12

Gigantism: Excessive height with normal body proportions.
Acromegaly: Thickening of bones in the eyebrow ridge, lower jaw, hands, and feet.

Question 13

What does thyroid-stimulating hormone (TSH) do?

Answer 13

TSH stimulates the thyroid gland to secrete thyroxine.

Question 14

What does adrenocorticotropic hormone (ACTH) do?

Answer 14

ACTH stimulates the adrenal cortex to secrete aldosterone or cortisol.

Question 15

What does prolactin do?

Answer 15

Prolactin stimulates milk production in response to infant suckling.

Question 16

What are gonadotropic hormones and their functions?

Answer 16

FSH: Stimulates ova development in females and sperm development in males.
LH: Triggers ovulation and progesterone production in females; testosterone production in males.

Question 17

What is thyroxine (T4) and its functions?

Answer 17

Thyroxine (T4) increases metabolism, glucose use, and cellular respiration, raising body temperature.

Question 18

What is goitre?

Answer 18

Goitre is the enlargement of the thyroid gland due to a lack of iodine, causing excessive TSH secretion.

Question 19

What does calcitonin do?

Answer 19

Calcitonin lowers blood calcium levels by promoting calcium absorption into bones.

Question 20

What does parathyroid hormone (PTH) do?

Answer 20

PTH raises blood calcium levels by releasing calcium from bones.

Question 21

What hormones does the adrenal medulla secrete?

Answer 21

The adrenal medulla secretes adrenaline (epinephrine) and noradrenaline (norepinephrine), which increase heart rate, breathing, and blood glucose levels.

Question 22

What does aldosterone do?

Answer 22

Aldosterone promotes sodium and water reabsorption in the kidneys, increasing blood pressure.

Question 23

What does cortisol do?

Answer 23

Cortisol increases blood glucose by converting fats and proteins to glucose, reduces inflammation, and is part of the long-term stress response.

Question 24

What are the functions of insulin and glucagon?

Answer 24

Insulin: Lowers blood glucose by helping cells absorb glucose.
Glucagon: Raises blood glucose by stimulating glycogen breakdown in the liver.

Question 25

What hormones help regulate blood sugar levels?

Answer 25

Insulin, glucagon, adrenaline, cortisol, and thyroxine regulate blood sugar.

Question 26

What is hypoglycemia?

Answer 26

Hypoglycemia is low blood sugar caused by excess insulin or low glucagon, leading to hunger, weakness, or death.

Question 27

What is hyperglycemia?

Answer 27

Hyperglycemia is high blood sugar, often seen in diabetes mellitus, with symptoms like fatigue, thirst, and increased urination.

Question 28

What are the two types of diabetes mellitus?

Answer 28

Type I: Caused by degeneration of beta cells, leading to insulin deficiency, often before age 20.
Type II: Caused by insulin resistance or inability to use insulin, usually in older adults.