Homeostasis

Question 1

Homeostasis

Answer 1

Physiological processes operate within limits
-bodys tendency toward internal stability
challenged by 1)metabolic needs and byproduces 2)external environment changes
-maintained by the coordinated activities of bodily systems and organs

Question 2

regulating body temp

Answer 2

radiation-transfer of heat by electromagnetic radiation
conduction-direct ranger of heat between objects touch cold/warm surface
convection-transfer of heat via movement of gas/liquid (windy day)
evaporation-energy needed to transfer grom liquid to gas

Question 3

Classify body temp in animals

Answer 3

1_ warm-blooded vs cold-blooded
Problem- cold-blooded animals achieve warm body temp
2) homeotherm vs poikotherm
-homeotherms regulate their body temp around an elevated set point
-poikilotherms conform to their environment
problem- somve poik have stable temps, some home modulate their temps.
Endotherm vs ectotherm-
Endotherms rely on metabolic head (birs/mammals)
Ectotherms rely on external sources of heat. (fish, amphibians, reptiles, arthropods.

Question 4

Endotherm vs ectotherm-

Answer 4

Endotherms rely on the metabolic head (birds/mammals) Endotherms have a narrow range of temp. use most of their energy to maintain body temperature, etc.

Ectotherms rely on external sources of heat. (fish, amphibians, reptiles, arthropods) tolerate wider ranges of temps than endo. Their activity is constrained by environmental temperature: endotherm is less affected.

Question 5

Ectotherms

Answer 5

gain lose heat from the external environment
temperature regulation via behavioral
1)orientation to sun
2)color change
3)changes in shape and posture
4)shutting behavior
5)basking and shivering

Question 6

Endotherms

Answer 6

the heat produced by metabolism
1)large quantities of food needed
2)behavior can reduce energy demands
Heat lost by radiation, conduction, convection, evaporation
-influenced by size and insulation
-control blood flow to the surface and adjust hair/fur
-sweating and panting, but losing water

freezing adaptations
countercurrent heat exchange can limit heat loss- cold blood is heated as it returns to core
thermogensis- via shivering and fa metabolism

Question 7

freezing adaptations

Answer 7

countercurrent heat exchange can limit heat loss- cold blood is heated as it returns to core
thermogensis- via shivering and fa metabolism

Question 8

Heat lost adaptations

Answer 8

by radiation, conduction, convection, evaporation
-influenced by size and insulation
-control blood flow to the surface and adjust hair/fur
-sweating and panting, but losing water

Question 9

Torpor

Answer 9

temporary reduction in body temp during periods of inactivity slows metabolism
Hummingbirds in the morning and night reduce heat
Smaller endotherms only
Hibernation- extended torpor that lasts several weeks.

Question 10

Osmotic regulation

Answer 10

Regulation of internal fluid and its composition, another form of homerostatis

Question 11

Osmoconformers

Answer 11

fluids inside animals are isotonic with sea water, therefore no osmotic gradient exists
-marine invertebrates
-cartilaginous fishes

Question 12

Osmorgulators

Answer 12

-most vertebrates must regulat blood osmoliarty to achieve homeostasis
-water loss from respiration, evaporation and excretion
replaced by drinking, food, and metabolic water
Humans get water by drinking
Rodendts metabolic water

Question 13

nitrogenous waste

Answer 13

ammonia is a toxic byproduct of protein oxidation
direct elimination-immediate removal via gills or dilute urin (fish)
Urea-less toxic than ammonia can be diluted, source of water loss (urine) fros, monkey us
Uric acid- crystal can be exerted without water, energetically expensive eg) birds lizzards

Question 14

Osmoregualry organs

Answer 14

goal-removal of harmful byproducts
a)protonephridia with flame cells (flatworms)
b)nephridium (annelids, mollusks)
c)Malpighian tubules (insects)
d) kidneys (vertebrates)

Question 15

Freshwater fish excretion

Answer 15

water tends to enter the body from the environment
solutes tends to leave the body and enter environment
excrete large volumes of dilute urine

Question 16

marine ray-finned fish excretion

Answer 16

water tends to leave the body and enter environment
solute tend to enter water
drink large amounts of water and produce little urine

Question 17

sharks and rays excreteion

Answer 17

osmoconformers-blood isotonic with water

Question 18

Mammalian kidney

Answer 18

-an organ of water regulation and nitrogenous waste removal
1) Blood enters glomerulus(bowman’s capsule)
-acts as filter that removes water and small molecules(not blood cells or protein) from blood
-filtrate continues to the proximal convoluted tubule
2)Proximal convoluted tubules
- 2/3 of filrate volume and all its glucose, amino acids, and vitamins are reabsorbs via active tranporation
3)loop of henie
- Descending lim permeable only to water
4)distal convoluted tubule
-ascending lim impermeable to water and solutes, actively transports NaCl to surrounding
5)collecting ducts
-fluid moves to collecting ducts solute outside the collecting ducts cause more water to leave urine
6)uterer to bladder

Question 19

glomerulus(bowman’s capsule)

Answer 19

1) Blood enters glomerulus(bowman’s capsule)
-acts as filter that removes water and small molecules(not blood cells or protein) from blood

Question 20

Proximal convoluted tubules

Answer 20

Proximal convoluted tubules
- 2/3 of filrate volume and all its glucose, amino acids, and vitamins are reabsorbs via active tranporation

Question 21

loop of henie

Answer 21

loop of henie
- Descending lim permeable only to water

Question 22

distal convoluted tubule

Answer 22

4)distal convoluted tubule
-ascending lim impermeable to water and solutes, actively transports NaCl to surrounding

Question 23

collecting ducts

Answer 23

5)collecting ducts
-fluid moves to collecting ducts solute outside the collecting ducts cause more water to leave urine
6)uterer to bladder

Question 24

Role of hormones

Answer 24

-the final concentration of urine depends on the permeability of the walls of the duct and the collecting duct
-permeability is controlled by antidiuretic hormone (ADH)
- when osmotic pressure is low eg(dehydration) ADH is released and increases the permeability of ducts
-more water is reabsorbed urine becomes more concentrated, thirst stimulated
- Absence of ADH, collecting ducts remain impermeable, dilute urine

Question 25

Longer loop of Henle

Answer 25

Deeper into renal medulla, allowing for more reabsorption of water