Osmoregulation

Question 1

What regulates changes in the internal environment of an animal?

Answer 1

Homeostasis mechanisms.

Question 2

What is the internal environment of vertebrates?

Answer 2

The interstitial fluid.

Question 3

What is homeostasis?

Answer 3

The maintenance of a relatively stable internal environment despite changes to external environment - internal (usually) changes less than external.

Question 4

How do homeostasis mechanisms maintain internal conditions with in a small range of values?

Answer 4

It is not constant and only occurs via the coordination of chemical and electrical processes.

Question 5

What are the two extremes that animals can undergo to cope with environmental fluctuations?

Answer 5

Regulator or conformer

Question 6

What is a regulator?

Answer 6

A regulator uses homeostasis mechanisms to moderate internal changes in the face of external fluctuations. (Endotherms = thermoregulation)

Question 7

What is a conformer?

Answer 7

A conformer changes some conditions in the body that vary with external changes.

Question 8

How is heat produced?

Answer 8

Metabolism

Question 9

What is ingested energy in animals used for?

Answer 9

It is used for work, it can be stored, excreted as waste and released as heat

Question 10

What is the metabolic rate of an animal?

Answer 10

It is the amount of energy an animal uses in a unit of time; the sum of all energy that requires biochemical reactions that occur over a given interval.

Question 11

How is the metabolic rate of an animal measured?

Answer 11

Measured by monitoring an animal’s rate of heat loss, oxygen consumption and co2 prodution.

Question 12

What is the Basal Metabolic Rate? (BMR)

Answer 12

It is the stable rate of energy metabolism measured in mammals and birds under conditions of minimal environmental and physical stress.

Question 13

What is the Standard Metabolic Rate? (SMR)

Answer 13

An animal with varying body temperatures is maintained at a selected body temperature and their resting and fasting metabolism at a given body temperature.

Question 14

What are some influences on metabolic rate?

Answer 14

Size, internal and external work, tissues growth and repair, time, season, age, sex, stress, type of food

Question 15

What are some ways that birds and mammals acclimate and acclimatize?

Answer 15

They can adjust their amount of insulation and vary capacity for metabolic heat production.

Question 16

What are some ways ectotherms acclimate and acclimatize?

Answer 16

They make adjustments at a cellular level (like production of cryoprotectants)

Question 17

What is torpor?

Answer 17

The physiological state in which activity is low and metabolism decreases. Conserves energy during environmental extremes.

Question 18

What is an example of long-term torpor?

Answer 18

Hibernation: evolved as an adaptation to cold and food scarcity

Question 19

What is an example of summer torpor

Answer 19

Estivation: slow metabolism and inactivity due to heat

Question 20

What animal undergoes daily torpor?

Answer 20

The hummingbird

Question 21

What is osmoregulation?

Answer 21

The management of the body’s water content and solute composition

Question 22

What is osmolarity?

Answer 22

Osmoles of solute particles/volume (L)

Question 23

What is one osmole?

Answer 23

One mole of osmotically active particles

Question 24

What does isoosmotic with a medium mean?

Answer 24

It means that an organism’s body fluids have the same osmotic pressure as a medium (most marine invertebrates)

Question 25

What does being hyperosmotic with the environment mean?

Answer 25

It means that the organism has a higher osmotic concentration than the medium (fresh water organisms)

Question 26

What does being hypoosmotic with the environment mean?

Answer 26

It means that the organism has a lower concentration that the medium (marine body fish)

Question 27

What is an osmoconformer?

Answer 27

An animal not actively adjusting its internal osmolarity because it is isoosmotic with its environment.

Question 28

What is an osmoregulator?

Answer 28

An animal thats body fluid has a different osmolarity than its environment and spends energy to control its internal osmolarity.

Question 29

What happens to an organism when they are hypoosomotic with their environment (like marine body fish)

Answer 29

Since the organism will have a higher internal concentration of solute compared to the outside and cause an influx of water, the organism will discharge excess H2O.

Question 30

What happens to an organism when they are hyperosmotic with their environment (like fresh water fish)

Answer 30

Since the organism will have a lower internal concentration of solute compared to the outside and cause a discharge of water, the organism will take in water to prevent this

Question 31

Describe characteristics of organisms that have a fresh water osmotic balance (ex, fresh water fish)

Answer 31

Fresh water osmotic balance organisms are osmoregulators that gain water (hyper) via osmosis and food. They lose salts by diffusion and excretion and regain salts in food and active uptake from surroundings

Question 32

Describe characteristics of marine invertebrates that have a seawater osmotic balance

Answer 32

Marine invertebrates are osmoconformers that are also isoosmotic with their environment. However, their individual solute concentration does not equal that of the sea water; the total osmolarity does. They conform to the osmolarity of the ocean and regulate internal ionic composition.

Question 33

Describe characteristics of marine vertebrates that have a seawater osmotic balance

Answer 33

Marine vertebrates are osmoregulators that lose H2O by osmosis (hypo) and gain water and salt in food and lose salt by active transport out of gills and urine.

Question 34

What are stenohaline organisms?

Answer 34

They cannot tolerate changes in external osmolarity

Question 35

What are euryhaline organisms?

Answer 35

They can tolerate substantial changes in their external osmolarity

Question 36

Describe characteristics of the osmotic balance in land animals

Answer 36

They have a risk of desiccation and have adaptions to reduce H2O loss: body coverings, nocturnal habits, drinking/eating moist foods, metabolic water

Question 37

How is water balance and disposal regulated?

Answer 37

It depends on the transport epithelia and animals can regulate the solute content of their body fluid that bathes cells.

Question 38

What are transport epithelia and their function?

Answer 38

They are layers of specialized cells that regulate solute movement; they move specific solutes in controlled amts in particular directions, joined by tight junctions and arranged in tubular networks with high surface area

Question 39

What is anhydrobiosis?

Answer 39

The ability to survive in a dormant state when the habitat dries up