u2: endocrine system

Question 1

is the endocrine or nervous system faster?

Answer 1

• endocrine can take seconds to days
• nervous reacts to stimuli within 1 to 10 sec
• thus, endocrine is slower + longer acting effects

Question 2

paracrine signalling

Answer 2

cell to cell communication where a cell releases a chemical messenger, causing changes in NEARBY cells

Question 3

endocrine signalling

Answer 3

signals (hormones) produced in one part of the body travel through circulation to reach far-away targets

Question 4

wht is the endocrine system comprised of?

Answer 4

all hormone-secreting cells and glands in the body

Question 5

what are the types of hormones?

Answer 5

• lipid (steroid)
• water-soluble

Question 6

define lipid (steroid) hormones

Answer 6

diffuse through lipid bilayer and bind to receptor proteins to activate specific genes

Question 7

define water-soluble hormones

Answer 7

attach to receptor on plasma membrane which activates enzymes (or effector molecules) inside cell that trigger protein prod’n

Question 8

examples of lipid (steroid) hormones

Answer 8

• estrogen
• progesterone
• testosterone
• aldosterone

Question 9

examples of water-soluble hormones

Answer 9

• epinephrine
• norepinephrine
• Thyroid-stimulating hormone (TSH)
• human growth hormone (hGH)

Question 10

how does the thyroid gland system work?

Answer 10

1. thyroid gland releases thyroxine (T3 nd T4)
2. anterior pituitary gland releases TSH which causes thyroid to release thyroxine.
3. since thyroxine increases, it is noticed by hypothalamus and anterior pituitary gland and the prod’n of TSH is stopped

Question 11

menstrual cycle

Answer 11

monthly cycle of events in a sexually mature female which prepares the uterus for implantation of a fertilized egg

Question 12

endometrium

Answer 12

tissue lining the uterus

Question 13

follicle

Answer 13

structure in ovary which contains an oocyte (immature egg/ovum)

Question 14

corpus luteum

Answer 14

• temporary endocrine structure found in ovary which secretes progesterone and estrogen
• follicle after egg has been released

Question 15

menstrual cycle: day 1-6

Answer 15

• drop in hormone lvls (estrogen/progesterone) indicate body isn’t pregnant
• triggers shedding of endometrium

Question 16

menstrual cycle: day 7-14

Answer 16

• FSH lvls rise, follicle begins developing
• as follicle develops, estrogen lvls increase = increase in LH
• endometrium thickens + blood supply increases to prep for fertilization

Question 17

menstrual cycle: day 14-15

Answer 17

follicle produces a mature egg which bursts from ovary (ovulation)

Question 18

menstrual cycle: day 16-28

Answer 18

• egg travels down fallopian tube where it may be fertilized
• corpus lutem develops and secretes progesterone to thicken endometrium
• if fertilization doesn’t happen, cycles starts again at day 1

Question 19

how does stress make u hungrier?

Answer 19

1. cortisol and adrenaline hormones rise, causing removal of glycogen from liver to get energy
2. once stress is gone, body replaces glycogen from liver

Question 20

male reproductive system

Answer 20

1. hypothalamus in brain releases GnRH
2. GnRH signals pituitary gland to release LH and FSH: (LH increases prod’n of testosterone, which helps make sperm + FSH increases prod’n of molecules for spermatogenesis) = positive feedback loop
3. if testosterone lvls too high, GnRH/FSH/LH restrcited = negative feedback loop