excretion, topic 5 pt1

Question 1

what is homeostasis?

Answer 1

the ability of an organism to maintain it’s internal makeup

Question 2

why is homeostasis sometimes called dynamic equillibrium?

Answer 2

because the body bounces between two set limits, one high and one low

Question 3

what is excretion?

Answer 3

the process of removing metabolic wastes from the body

Question 4

what is the product of excretion?

Answer 4

urine

Question 5

how are waste products removed from cell production site?

Answer 5

by the blood

Question 6

what does the kidney remove?

Answer 6

the waste and excretes it from the environment

Question 7

what are the 3 functions of the excretory system?

Answer 7

1. excretion of metabolic wastes
2. osmoregulation
3. regulation of body fluid composition (pH etc…)

Question 8

what is osmoregulation?

Answer 8

regulation of water and salt in body fluids

Question 9

what are 3 waste products in the excretory system?

Answer 9

-carbon dioxide
-water
-nitrogenous wastes (products of protein and nucleic acids digestion)

Question 10

how is carbon dioxide excreted?

Answer 10

through the skin and respiratory surfaces

Question 11

how is water excreted?

Answer 11

through the skin, respiratory surfaces and kidneys

Question 12

how are nitrogenous wastes excreted?

Answer 12

mainly through the kidneys, and some from the skin

Question 13

what are 3 nitrogenous wastes?

Answer 13

1. ammonia
2. uric acids (in birds)
3. urea (in mammals)

Question 14

can ammonia accumulate in body?

Answer 14

no

Question 15

why and what does ammonia need to convert into?

Answer 15

Because it is very toxic.
-converts into less toxic uric acid and urea

Question 16

what is uric acid converted from?

Answer 16

ammonia
-uric acid is non toxic

Question 17

is uric acid soluble?

Answer 17

not really, can be excreted as a paste with little water loss

Question 18

what is urea converted from?

Answer 18

ammonia
-urea is less toxic than ammonia

Question 19

what is urea produced by?

Answer 19

the liver

Question 20

how is urea excreted?

Answer 20

in a concerntrated form
-requires more water to excrete than uric acid

Question 21

what do the kidneys produce?

Answer 21

urine by filtering the blood

Question 22

what do the 2 ureters do?

Answer 22

transport urine from kidneys to bladder

Question 23

what does the urinary bladder do?

Answer 23

stores urine

Question 24

what does the urethra do?

Answer 24

carries urine to environment

Question 25

what are the 3 kidney parts?

Answer 25

1. cortex: outer region
2. medulla: just below the cortex
3. pelvis: a hallow chamber within the medulla

Question 26

what are the cortex and medulla of each kidney made up of?

Answer 26

about one million nephrons

Question 27

what is a nephron?

Answer 27

structural and functional unit of the kidney

Question 28

what is the bowman’s capsule?

Answer 28

double walled chamber (start of the tube)

Question 29

what is the glomerulus?

Answer 29

a network of capillares within the bowman’s capsule

Question 30

what happens in the glomerulus?

Answer 30

filtration of blood plasma (particle size and blood pressure)

Question 31

what does high pressure do regarding the glomerulus?

Answer 31

plasma passes through holes in the glomerulus into the bowman’s capsule

Question 32

what happens when plasma enters the capsule?

Answer 32

it is filtrated

Question 33

what does the proximal tubule do?

Answer 33

active transport of valuble substances back into the blood
-glucose, amino acids, sodium ions

Question 34

do all substances get reabsorbed in the proximal tube?

Answer 34

no
-urea, toxic subtances, some salt and alot of water dont get reabsorbed here