10/13
SI A ECL 365
1.
Why is water / salt regulation critical for life? a.
Body of vertebrates consists of 70-80% water i.
inside cells, surrounding cells ii.
most chemical reactions in the body occur in water b.
Many salt ions important for body function are dissolved in water i.
cofactors for metabolic reactions (e.g. muscle contraction) ii.
ions for regulation of pH
2.
What is the purpose of water balance? a.
Keeping body from drying out or getting flooded
3.
True / False Osmoregulation and salt balance are synonymous words. a.
True
4.
What is the purpose osmoregulation? a.
Keeping the body from getting too salty or not getting enough salt.
5.
Name methods of minimizing evaporative water loss. a.
Decreasing moisture of exhaled air i.
Turbinates and countercurrent heat exchange in homeotherms b.
Resistant skin – scales/plate, thick skin/hair/feathers c.
Poikilothermy – don’t need to eliminate excess heat d.
Behavioral adaptations i.
Burrowing / staying in shade ii.
Nocturnal activity iii.
Estivation
6.
What are other ways of reducing water loss in terrestrial vertebrates? a.
Produce concentrated urine b.
Produce very dry feces
7.
Approximately how much water do Kangaroo rats consume? a.
None – all comes from metabolic processes
8.
Is water loss proportionally greater in large or small animals? a.
Small animals – greater surface area to volume ratio
9.
True / False All organisms regulate their salt/water balance. a.
False
10.
What is dialysis? a.
Artificial filtering of the blood in people with kidney failure. Takes several hours a day?

11.
The ____________ is the primary organ of salt / water balance in reptiles, birds, and mammals and receives _____________% of blood flow, though is less than
______% of body mass of the animals. a.
Kidney, 20-25, <1
12.
What are 3 functions of the kidney a.
filtration of the blood b.
reaabsorption of useful materials c.
Secretion of waste materials
13.
The functional unit of the kidney is the _________________. a.
Nephron
14.
How is waste in the blood converted to urine? a.
Wastes are extracted from blood on nephron i.
Leaky capillary bed (glomerulus) surrounded by Bowman’s capsule of nephron ii.
Glomerular flow commences as blood ultrafiltrate forced

Bowman’s capsule iii.
Proximal tubule main site of reabsorption (nutrients, glucose, amino acids, vitamins; Na, Cl, K ) iv.
Loop of Henle main site for water reabsorption (urine concentration) (Desert animals have long loops of Henle) v.
Distal tubule main site for secretion of waste substances
1.
N wastes: ammonia, urea, uric acid
2.
Excess ions: Na, Cl, K, etc vi.
Collecting ducts collect the modified filtrate (urine) of many nephrons into larger tubes and directs them to the urinary tract for excretion.
15.
In what type of environment do animals with the longest loops of Henle reside? a.
Desert
16.
What vertebrate groups face challenges when it comes to osmoregulation? a.
Marine Fishes b.
Freshwater fishes and amphibians c.
Terrestrial vertebrates
17.
What are three ways marine fish combat their tendency to lose water and gain salts due to high osmolality (salt content) of environment? a.
Be as salty as the environment – hagfish i.
Conform to their environment

b.
Have as high osmotic pressure as environment (e.g. cartilaginous fish by use of urea) i.
Chondrycthyes increase their osmolality by having high levels of urea in body fluids. c.
Have mechanisms to counteract water loss and salt gain (e.g. most bony fish) i.
Osteichthyes have body fluids with lower osmolalities than sea water, so they tend to lose water and gain salts (mainly thru gills)
18.
How do bony fish osmoregulate? a.
Gill water-loss compensated by drinking water i.
(up to 80% body mass/day) b.
Kidney produces small amounts of urine c.
Excess salt pumped out through gills by special chloride cells i.
(energy costly process)
19.
What is a problem associated with living in fresh water for fish and amphibians? a.
Tendency to gain water and lose salts due to low osmolality (salt content) of environment
20.
How is the above problem solved? a.
Have mechanisms to counteract water gain and salt loss (similar in freshwater fish and amphibians) i.
Osteichthyes (and aquatic amphibians) have body fluids with higher osmolalities than freshwater, so they tend to gain water and lose salts (mainly thru gills in fish or skin in amphibians)
21.
Describe the regulatory mechanism utilized by fresh water bony fish (in reguards to osmoregulation). a.
Do not drink water b.
Kidney produces large amounts of dilute water c.
Salts actively pumped in through gills by special chloride cells i.
(energy costly process)
22.
Describe how freshwater amphibians osmoregulate. a.
Same to fish except that salt is absorbed by cells all over the body surface b.
Do not drink water c.
Kidney produces large amounts of dilute water d.
Salts actively pumped in through skin by special cells (energy costly process) e.
23.
What does stenohaline mean? a.
(narrow salt): cannot tolerate wide range of salinity and live only where salinity constant (either marine or freshwater).
24.
What does Euryhaline mean?

a.
(wide salt): tolerate wide range of salinity and can move between salt and freshwater
25.
What does Diadromous mean? a.
migrate between fresh and salt water
(involves progressive changes in physiology)
26.
______________________ organisms live most of their adult life in fresh and spawn in saltwater. ___________________ organisms live most of their adult life in salt and spawn in freshwater. a.
Catadromous, anadromous
27.
True / False Terrestrial vertebrates need not worry about their salt / water balance because they do not live in aquatic environments. a.
False - Need to conserve water due to lower water in environment (most extreme in desert animals).
28.
How is osmoregulation accomplished in terrestrial vertebrates? a.
Produce concentrated urine (done by kidneys) b.
Produce very dry feces (done by digestive tract) c.
Decrease evaporative water loss thru lungs and skin