24. Osmoregulation and Excretion

Question 1

define osmoregulation

Answer 1

balancing uptake and loss of water and solutes such as salt inside the body

Question 2

define osmlarity

Answer 2

the number of particles in a solution

Question 3

define osmosis

Answer 3

when two solutions seperated by a membrane differ in osmolarity, its the passive movement (no energy required) of WATER between each side of the membrane. kind of like diffusion except its only with water molecules

Question 4

define iso-osmotic

Answer 4

both solutions have the same osmolarity, no net moemvent of water

Question 5

define hyper-osmotic

Answer 5

solution which has greater concentration of solutes (has less water) so water will move into this solution through the plasma membrane (osmosis)

Question 6

define hypo-osmotic

Answer 6

solution whihc has lower concentration of solutes (more water), so water moves away from this solution (osmosis)

Question 7

what are osmoconformers?

Answer 7

marine animals (such as sea urchins and flatworms) that dont adjust their osmolarity. their body fluids are iso-osmotic to the enviornment.

OPPOSITE OF OSMOREGULATORS

Question 8

what are osmoregulators?

Answer 8

animals that control their body fluids at differnt osmolarity than the envionrment. allow animals (such as arthropods, reptils and mammals) to live in a larger variable of enviornments

Question 9

where does osmoregulation get its energy from? why is this important?

Answer 9

osmoregulation uses transport epithelia (TE) which allows movement of specific solutes between the plasma membrane

Question 10

what do tight junctions do in transport epithelia?

Answer 10

prevent passive flow of water and solutes between cells

Question 11

what are the two categories of tolerance to variability in the osmolarity in the evironment? what do each do?

Answer 11

stenhaline animals - cant tolerate much change in the external osmoregularity

euryhaline animals - can tolerate larger changes in external osmolarity

Question 12

how do terrestrial animals cope with water loss? three points

Answer 12

impervious body cover (reptiles)

lifestyle (notcturnal)

drinking water and eating moist foods

Question 13

what are the osmoregulatory systems of marine inveritbrates?

Answer 13

mostly osmoconformers (body changes with enivronmet) drinking sea water and excreting salt through gills with transport epithelia energy

Question 14

how do marine catiligious fish osmregulate?

Answer 14

they maintain high levels of urea in body fluids which increase osmolarity - hypersomotic to the environment

Question 15

what does excretion involve in terms of osmoregulation?

Answer 15

getting rid of nitrogenous aste

Question 16

what are the three types of waste excreted? what type of organisms excrete them?

Answer 16

urea - amphibians, sharks, reptiles and mammals

uric acid - birds insects reptiles

ammonia - aquatic species

Question 17

what is a benefit and negative impact of ammonia?

Answer 17

very soluable and passes easily through membranes hwever it is very toxic - therefore tolerable in low concerntrations

aquatic species

Question 18

what is a positve and a negative impact of excreting urea?

Answer 18

its must less toxic so it can be stored, therefore requires less water to excrete. however it costs a lot more energy to converty the ammonia to urea

(mammals, sharks, turtles and adult amphibians)

Question 19

what is a positive and negative of excreting uric acid?

Answer 19

its non toxic and INSOLUABLE in water - so its excreted as a semi solid paste (requires little water). very costley to produce because a very small amount of water is used.

(reptiles and all birds, insects)