Lecture 15 - Excretion

Question 1

Diffusion

Answer 1

Movement of solutes from an area of higher concentration to an area of lower concentration to reach equilibrium

Question 2

Osmosis

Answer 2

Diffusion of water through a selectively permeable membrane

Question 3

Osmolarity

Answer 3

The sum of osmotically active particles in solution

Question 4

Osmoregulation

Answer 4

is the controlled movement of solutes between internal fluid and environment

Question 5

Stuff transferred by active transport

Answer 5

Water
Salt
Nutrients
Waste

Question 6

Osmoregulation

Answer 6

the control of solute concentrations and water balance

Question 7

Human excretory system divided into three steps

Answer 7

Step 1: Filtration
Step 2: Reabsorption and secretion
Step 3: Concentration-counter current multiplier

Question 8

Osmoregulation in freshwater challenges

Answer 8

• invertebrates and vertebrates have a similar challenge
• tendency to gain water and lose salts
• low environmental osmolarity

Question 9

solutions to Osmoregulation in freshwater

Answer 9

• reducing permeability
• active transport
• usually uptake ions in respiratory surfaces

Question 10

Marine organisms Osmoregulation challenges tend to be that?

Answer 10

they lose water by osmosis and gain salt

Question 11

Are most marine vertebrates are osmoregulators

and ionoregulators?

Answer 11

yes

Question 12

how do the gills aid osmoregulation in marine vertebrates?

Answer 12

Active secretion of NaCl

Question 13

What doe the kidneys excrete in marine vertebrates?

Answer 13

MgSO4 and very little water

Question 14

What do the kidneys excrete in freshwater vertebrates?

Answer 14

dilute urine

Question 15

how do the gills aid osmoregulation in freshwater vertebrates?

Answer 15

gills actively absorb NaCl but water does tend to enter osmotically

Question 16

What animal groups produce urine hyperosmotic to blood?

Answer 16

mammals(including marine)

birds

Question 17

What animal groups produce urine hyperosmotic to blood?

Answer 17

amphibians

freshwater fish

Question 18

What animal groups produce urine Isosmotic to blood?

Answer 18

marine fish

marine reptiles

Question 19

Vertebrate kidney general structure

Answer 19

• Thousands or millions of nephrons
• Convoluted tubules (prx & dist) collecting duct
• Mammals & some birds have loop of Henle

Question 20

Metanephros kidney

Answer 20

kidney found in adult reptiles,birds and mammals

Question 21

Opisthonephros

Answer 21

kidney found in lampreys, fish and amphibians

Question 22

functional unit of the kidney?

Answer 22

nephron

Question 23

What are the steps in human excretion?

Answer 23

Step 1: filtration
Step 2:reabsorption & secretion
Step 3: concentration

Question 24

What structures does filtration involve?

Answer 24

Glomerulus

Bowman’s capsule

Question 25

How many litres of filtrate a day do humans produce?

Answer 25

180 L of filtrate per day