endocrine system

Question 1

what is a gland?

Answer 1

an organ that makes a secretion (can be an enzyme, hormone, etc.)

Question 2

what is the function of the endocrine system?

Answer 2

to work with the nervous system to effect internal regulation and maintain homeostasis

Question 3

what is an exocrine gland?
what products does it make?
give example

Answer 3

it is a gland that secretes products through a duct leading to a specific target

• ducts can be short, long, branched, or simple
• makes variety of products including enzymes or ions
  eg. liver, sweat glands, salivary glands

Question 4

what is an endocrine gland?
what products does it make?
give example

Answer 4

it is a gland that secretes products into blood or lymph, does not use ducts

• secretions are hormones
  eg. pancreas, thyroid, ovary

Question 5

what is a hormone?

Answer 5

a hormone is a chemical messenger that is released in one part of the body and regulates the activity of another part of the body

Question 6

why do hormones only effect certain organs?

Answer 6

because organs have specific receptors that only work with specific hormones

Question 7

which 2 endocrine glands are part of the central nervous system?

Answer 7

1. hypothalamus

2. pituitary

Question 8

the pituitary gland is split into what? how many hormones do they produce?

Answer 8

1. the anterior pituitary gland
   - produces 6 hormones (4 releasing, 2 not)
2. the posterior pituitary gland
   - does not produce hormones, but stores 2 from hypothalamus

Question 9

what is the relationship between the hypothalamus and the pituitary gland? does the hypothalamus effect both pituitary glands the same?

Answer 9

the hypothalamus is the control center which targets the pituitary gland, which then directs other parts of the body
-no hypothalamus works differently on both

Question 10

what 3 things does the hypothalamus do?

Answer 10

1. make hormones that stimulate hormone production in the anterior lobe
2. makes ADH and oxytocin
3. Control of sympathetic output to adrenal medulla

Question 11

what are the 2 hormones stored in the posterior lobe? what do they do when released?

Answer 11

1. oxytocin
   - causes contraction of the uterus which is important during childbirth and causes the release of milk during
   breastfeeding
2. antidiuretic hormone (ADH)
   -increases water absorption in the kidney (triggered when blood has high osmolarity) and causes vasoconstriction (narrowing of blood
   vessels)

Question 12

how does the hypothalamus gland effect the anterior lobe? what effect does it cause? what other hormones does it cause?

Answer 12

The hypothalamus secretes 4 releasing hormones which instruct the anterior pituitary to “release” the corresponding hormone to have a further effect on a gland or tissue

• causes a cascading effect
• also produces prolactin inhibiting hormone to influence milk production
• and prolactin releasing hormone to influence milk production

Question 13

how many hormones does the thyroid produce? what are they?

Answer 13

1. thyroxin

2. calcitonin

Question 14

how is the production of thyroxin stimulated? what does thyroxin do in the body?

Answer 14

• Stimulated by thyroid stimulating hormone from anterior pituitary
• plays vital roles in digestion, heart and muscle function, brain development and maintenance of bones, and affects protein metabolism

Question 15

how is calcitonin regulated, what does it do?

Answer 15

• regulated by negative feedback of calcium ion levels in the blood
• works to reduce blood calcium and phosphate levels when they are too high

Question 16

where is the parathyroid in relation to the thyroid?

Answer 16

on the posterior side of the thyroid

-thyroid is located under vocal cords

Question 17

what hormone does the parathyroid produce? how it it regulated, what does it do?

Answer 17

the parathyroid hormone.

• also regulated by negative feedback loop of calcium ion levels in blood
• works to increase blood calcium levels when they are too low

Question 18

where are hormones produced in the pancreas?

Answer 18

in the islets of langerhans

Question 19

what hormones are produced by the pancreas, what cells produce them, and what is their main effect?

Answer 19

1. glucagon –> produced by alpha cells
   - main effect is to increase blood glucose levels
2. insulin –> produced by beta cells
   - main effect is to decrease blood glucose levels

Question 20

how many adrenal glands do humans have, where are they found?

Answer 20

2 –> 1 on top of each kidney

Question 21

what are the three layers of the adrenal glands?

Answer 21

1. capsule
2. adrenal cortex
3. adrenal medulla

Question 22

what hormones does the adrenal cortex produce, what zones are these in, what are their main effects?

Answer 22

1. aldosterone - outer zone
   - triggers reabsorption of sodium, which leads to increased water reabsorption
2. cortisol - middle zone
   - responds to stress, increases muscle metabolism, increases sugar storage
   - stimulated by anterior pituitary
3. testosterone/estrogen - inner zone
   - primary source of sex hormones until puberty and then sex glands take over
   - involved in the development of secondary sex characteristics

Question 23

what hormones does the adrenal medulla produce? what are their main effects?

Answer 23

1. epinephrine (adrenaline)
2. norepinephrine
   - Both are also neurotransmitters that respond to fear, excitement and danger
   - increase blood pressure
   - Epinephrine increases blood flow to heart and muscles
   - Norepinephrine decreases blood flow to the gut and skin