osmoregulation

Question 1

typical vertebrate water balance

Answer 1

Wdrink+Wfood+Wair-Wevaporated-Wsecreted; food and drink are the primary source and evaporation is the primary loss

Question 2

small organisms

Answer 2

higher water loss due to increased respiration for their high metabolic rates

Question 3

keratinized skin

Answer 3

prevents evaporative water loss through the skin but water is still lost through sweat and moist surfaces like the nostrils

Question 4

tree frogs

Answer 4

prevent water loss by spreading a waxy substance that they secrete over their skin

Question 5

nasal turbinates

Answer 5

maze like structure that cools expired air to prevent water loss because cool air holds less water than hot air

Question 6

water saving mechanisms

Answer 6

behavioral adjustments such as becoming nocturnal, raising the body temperature to reduce evaporative cooling, or concentrating and dehydrating waste

Question 7

concentrating excretory products

Answer 7

concentrating ability of the kidneys varies among groups but only birds and mammals can concentrate waste more than the body fluids; all groups but mammals also use another method

Question 8

salt glands

Answer 8

found in marine birds and reptiles, typically located in the orbit or the nasal cavity, secreted highly concentrated volumes of excess salt, salt is removed by a sodium potassium pump and concentrated via countercurrent flow

Question 9

vertebrate kidneys

Answer 9

weakest in fish and strongest in mammals, glomerulus determines amount of ultrafiltration and the length of the loop of Henle determines concentration

Question 10

glomerulus

Answer 10

made up of a net of fenestrated capillaries in the kidney that have holes allowing solutes to filter out, surrounded by the Bowman’s capsule

Question 11

blood flow through the kidney

Answer 11

blood enters through the efferent artery and flow is controlled by constriction there, blood enters the glomerulus where water and solutes filter out of the fenestrated capillaries and then flows out the afferent artery, water and solutes flow into bowman’s capsule and then into the nephron

Question 12

nephron

Answer 12

functional unit of the kidney serves to refine filtrates and concentrate urine

Question 13

distal tubule

Answer 13

collects filtrate and funnels it into the collecting duct where it will become urine

Question 14

cortical nephrons

Answer 14

85% of human nephrons located in high in the renal cortex that serve a regulatory role

Question 15

juxtamedullary nephrons

Answer 15

15% of human nephrons located close to the renal medulla, have a long loop of Henle that extends deep into the medulla

Question 16

proximal convoluted tubule

Answer 16

located at the beginning of the nephron after the Bowman’s capsule, reabsorb roughly 2/3 of glomerular filtrate

Question 17

loop of Henle

Answer 17

located after the PCT, sets up a large gradient of NaCl in the extracellular fluid of the medulla

Question 18

tubular portion

Answer 18

made up of a thin descending portion, thin ascending portion and a thick ascending portion, only the descending segment is permeable to water

Question 19

Single effect

Answer 19

the thick ascending segment is not permeable to water but is permeable to NaCl increasing osmotic pressure in the medulla even which enables concentration of filtrates in the collecting duct

Question 20

diureses

Answer 20

more water passes through creating dilute urine

Question 21

antidiureses

Answer 21

more water is reabsorbed creating concentrated urine

Question 22

ammonia

Answer 22

highly toxic waste generated by aquatic organisms because it is energetically inexpensive and soluble in water

Question 23

urea

Answer 23

produced during protein breakdown in the kidneys and transport, requires some energy to produce and is moderately toxic, produced by mammals and most amphibians

Question 24

uric acid

Answer 24

fairly non toxic highly concentrated preventing water loss but highly energetically expensive, excreted as a white paste or powder such as by birds

Question 25

crab eating frogs

Answer 25

maintain hyper osmosis while living in brackish water via high amounts of Urea and TMAO in the body fluids resulting in a net gain of water