test review

Question 1

what is homeostasis

Answer 1

stable bodily equilibrium, any self-maintaining physiological processes

Question 2

Fully explain thermoregulation and childbirth as examples of feedback systems (- and +)

Answer 2

thermo:
1. capillaries are flushed with warm blood and release heat from skin
2. body temperature decreases
3. hypothalamus heat-loss center shuts off (nervous system feedback)

reverse: low body temperature -> hypothalamus heat promoting center activates -> skin blood vessels constrict and minimizes heat loss -> body temp increases from heat retention, shutting heat promoting center off

childbirth: fetus’ head pushes against cervical opening -> nerve impulses transmit this to brain -> oxytocin is secreted -> thru bloodstream reaches cervix, promoting cervix to contract and push fetus’ head closer for childbirth

Question 3

osmoregulators vs osmoconformers, give examples

Answer 3

osmoregulators: organisms that can keep or regulate the solute concentrations of their body fluids to be more or less concentrated than their external environment. (e.g. humans, birds)

osmoconformers: marine animals that can regulate their internal environment as isotonic to that of the external environment (e.g. sea stars, molluscs)

Question 4

where, and from what molecules is urea generated?

Answer 4

amino acid remnants

Question 5

compare ammonia urea and uric acid; why do different organisms excrete different nitrogenous wastes?

Question 6

How is the structure of the nephron critical to it achieving its functions? (hint: concentration gradients, passive vs active transport, glomerulus, capillaries)

Answer 6

loop of henle and collecting duct are integral for concentrating the urine and reabsorbing key elements like water and salt

Question 7

Describe the hormonal system that impacts water balance, including the location of cells detecting osmotic potential, and the mechanism to respond to the stimulus of high blood osmotic potential.

Answer 7

aldosterone affects blood vessel water balance

adh triggers aquaporin movement in nephron lumen, allowing for increased water reabosrption when dehydrated

Question 8

In general, describe two different ways that you can increase blood pressure. Now describe the hormonal system to
regulate blood pressure and explain how it triggers the two responses described in the first part of this Q.

Answer 8

1. retrict diameter of vessels (angiotensin)
2. increase fluid volume in vessels (aldosterone increase na ion concentration, water follows)

Question 9

Why is constant hypertension a health risk

Answer 9

primary cause of kidney failure

Question 10

compare spermatogenesis and oogenesis

Answer 10

sperm: mitosis for more diploid, meiosis 1 and 2 to make 4 haploid spermatids, mature into spermatozoa

oocytes: create polar bodies which degenerate, one diploid oogonium duplicated through mitosis makes only one haploid egg through meiosis

Question 11

In general, describe two different ways that you can increase blood pressure. Now describe the hormonal system to regulate blood pressure and explain how it triggers the two responses described in the first part of this Q.

Answer 11

1. decrease diameter of blood vessels (angiotensin)
2. increase amount of fluid in the vessels (aldosterone increase na ion concentration in blood, water follow thru osmosis)