The Endocrine System

Question 1

What are the four principal functions of communication from cell to cell in the endocrine system?

Answer 1

1. gap junctions - join single unit smooth muscle cell.
2. neurotransmitters - released by neurons.
3. Paracrine - secreted by one cell and diffuse to nearby cells.
4. Hormones - chemical messengers transported by the bloodstream that stimulate response.

Question 2

What are the endocrine glands?

Answer 2

Hypothalamus
Pituitary 
Thyroid 
Parathyroid 
Adrenal
Pancreas
Gonads (ovaries & testes)
Thymus
Pineal

Question 3

How is the T cell activated?

Answer 3

1. antigen recognition
2. Costimulation (are you sure)
3. Clonal selection (creates more cells)
4. Attack

Question 4

How are B cells activated?

Answer 4

1. Antigen recognition
2. Antigen Presentation
3. Colonal Selection (creates more cells)
4. Differentiation
5. Attack

Question 5

What hormones do the posterior pituitary store?

Answer 5

Oxytocin and ADH
OT - sexual arousal, stimulate contractions, stimulate flow of milk.
ADH- vasopression and H2O retention (urine volume)

Question 6

What Hormones do the anterior pituitary store?

Answer 6

FOLLICLE STIMULATING HORMONE (FSH)- sex hormones, secretion of estrogen
LUTEINIZING HORMONE (LH) - ovulation, secrete testosterone
ADRENOCORTICOTROPIC HORMONE (ACTH) - secrete glucocorticoids
THYROID HORMONE (TSH) - stimulate secretion of thyroid
PROLACTIN PRL- synthesize milk
GROWTH HORMONE (GH) - stimulates mitosis and cellular differentiation.

Question 7

What are the four tropic hormones and the hormones the release?

Answer 7

FSH - estrogen, testosterone, progesterone
LH - estrogen, testosterone, progesterone
ACTH - Aldosterone, cortisol, and sex hormones
TSH - T3 (thyroxine) and T4 (triiodothyronine)

Question 8

What are the three chemical classes?

Answer 8

Steroids (derived from cholesterol; sex steroids), Peptides (chains of amino acids 3-200; hormones from- pituitary, hypo., and insulin), and Monomines (made from amino acids, catecholamines, melatonine; thyroid hormone)

Question 9

STEROIDS HORMONES:

Answer 9

penetrate plasma membrane and bind to internal receptors, influence expression of target cells, takes hours.

Question 10

PEPTIDE HORMONES:

Answer 10

CAN NOT penetrate target cells and need second messengers.

Question 11

How are hormones synthesized/transported to target organs?

Answer 11

NEURAL STIMULI: sympathetic nervous system stimulates adrenal medulla during stress. EX. child birth
HORMONAL STIMULI: Releasing and inhibiting hormones from the hypo. Only go to cells that have their receptors. EX. TSH, ACTH, FSH, LH
HUMORAL STIMULI:blood-borne stimuli. EX. increase in blood glucose release insulin. Decrease in blood glucose parathyroid hormone.

Question 12

What are transport proteins?

Answer 12

albumins and globulins synthesized by liver.

Question 13

How do target cells regulate their sensitivity to circulatory hormones?

Answer 13

Change the number of receptors. 2 ways:
UP-REGULATION- increase the number of receptors= increased sensitivity.
DOWN REGULATION - decrease the number of receptors= less sensitivity and long term exposure to hormone.

Question 14

How do hormones affect one another when targeting the same cell?

Answer 14

SYNERGIST- multiple hormones work together for greater effect.
PERMISSIVE - one hormone enhances the target organs response to the other hormones.
ANTAGONIST- one hormone opposes the action of another.

Question 15

How are hormones received from circulation?

Answer 15

hormones must be turned off after they serve their purpose. This is achieved by them being taken up or degraded by the Liver or Kidney. It is then excreted in bile or urine.