Lesson 4- Excretory System

Question 1

how is fluid balance maintained between the extracellular and intracellular fluid?

Answer 1

electrolyte homeostasis

Question 2

The function of the excretory system?

Answer 2

-eliminate body wastes
-maintaining osmolarity of body fluids

Question 2

what are electrolytes?

Answer 2

obtained from ingested foods, electrolytes are minerals that populate the intracellular and extracellular (including intravascular & interstitial fluid) fluid compartments

Question 3

what does the extracellular compartment include?

Answer 3

• the interstitial fluid bathing body cells
• the intravascular fluid in blood vessels

Question 4

what is our most important extracellular electrolyte?

Answer 4

sodium
other important ones are chloride and calcium ions

Question 5

which are the principal intracellular electrolytes?

Answer 5

potassium and magnesium

Question 6

what is osmosis? (amount of electrolytes control osmosis)

Answer 6

the flow of water between the extracellular and intracellular fluid compartments

Question 7

what happens if we consume too much sodium?

Answer 7

drives water into the extracellular compartment and increases its volume – increase in volume of the intravascular compartment causes an increase in blood pressure

Question 8

what happens when we consume too much sodium?

Answer 8

drives water into the extracellular compartment and increases its volume – increase in volume in the intravascular compartment causes an increase in blood pressure

Question 9

what happens when magnesium and potassium concentrations increase?

Answer 9

drive fluid out of the extracellular compartment and into body cells

Question 10

what is the primary system of osmoregulation in marine birds?

Answer 10

salt glands

Question 11

what is the primary system of osmoregulation in fishes?

Answer 11

gill filaments

Question 12

which organs consume the most energy (BMR) in humans?

Answer 12

liver - 27%
brain - 19%
skeletal muscles 18%

Question 13

what are the costs of osmoregulation?

Answer 13

1. difference in osmolarity of the animal<s body fluid and its environment
2. permeable skin= harder to maintain a fixed gradient
3. the amount of ATP required to operate the active transport pumps involved with moving solutes in and out of the body

Question 14

who is an osmoregulator?

Answer 14

freshwater animals
terrestrial animals

Question 15

who is an osmoconformer?

Answer 15

marine animals

Question 16

how do mammals (not flying birds) get rid of nitrogenous wastes?

Answer 16

the liver converts ammonia into urea- a less toxic but metabolically expensive to generate- urea requires water though

Question 17

how do animals without access to much water get rid of nitrogenous wastes?

Answer 17

birds, reptiles, insects and land snails eliminate wastes in the form of uric acid

Question 18

what is the excretory tubule called for invertebrates?

Answer 18

nephridium

Question 19

what is the excretory tubule called for vertebrates?

Answer 19

nephron
1. cortical nephron in a segment called the renal cortex
2. longer juxtamedullary nephrons that extend well into the renal medulla segment of the kidney

Question 20

what is the most basic type of excretory system?

Answer 20

the proto-nephridium in flatworms-
dead end tubules
cilia inside flame bulb drives interstitial fluid through bulk flow

Question 21

who has malpighian tubules?

Answer 21

animals with open circulatory systems

Question 22

what is the excretory system of annelids?

Answer 22

the metanephridia - convoluted tubules associated with blood capillaries