Module: The Excretory System and Homeostasis

Question 1

what is excretion?

Answer 1

the process by which waste and harmful substances, produced by chemical reactions occuring inside body cells

Question 2

list the 4 excretory organs

Answer 2

kidneys
lungs
liver
skin

Question 3

list the waste products excreted by each excretory organ

Answer 3

lungs: carbon dioxide, water vapour
kidneys: urea, water, some salts
liver: bile pigment
skin: urea, excess salts, water

Question 4

what do renal arteries do?

Answer 4

bring oxygenated blood from the heart (contains salts, urea, glucos, water

Question 5

what do renal veins do?

Answer 5

take deoxygenated blood that has been purified to the heart.

Question 6

list the 7 parts of the urinary system

Answer 6

renal veins
renal arteries
kidneys
ureters
bladder
sphincer muscles
urethra

Question 7

what is ultra filtration?

Answer 7

process of forcefully filtering the filtrate from the glomurelus into the Bowman’s capsule

Question 8

by what is urea produced and when?

Answer 8

it is produced by the liver in a process called deamination. this is the conversion of glucose and protein in the liver

Question 9

explain the process of how the nephrons work

Answer 9

• the blood is filtered from the glomorelus (bundle of blood capillaries) and moves into the Bowman’s capsule
• at the Bowman’s capsule, ultrafiltration takes place, and that filtrate moves to the proximal convoluted tubule.
• at the proximal convoluted tubule glucose, sodium (67%), and water (80%)
• at the loop of henly, urine is more concentrated so more water is conserved
• water regulation with the help of the anti-deuretic hormones occurs in the distal convu=oluted tubule.
• the filtrate moves to the collecting duct and once it leaves the nephrons/kidneys it is then known as urine.

Question 10

what is dialysis?

Answer 10

the process by which blood is filtered/cleaned artificially by a machine that imitates the kidneys

Question 11

list the 11 parts of the kidneys

Answer 11

renal artery
renal vein
pelvis
cortex
ureter
pyramid
medulla
glomerulus
Bowman’s capsule
nephron

Question 12

what is negative feedback?

Answer 12

correction to whatever change is going on in the body

Question 13

what 2 things would occur in the body if it is overheating? explain

Answer 13

vasodilation: cools down the body by causing the blood capillaries to get wider and move closer to th eskin to release excess heat

sweating

Question 14

what 2 things would occur in the body if it is overcooling? explain them

Answer 14

shivering: allows the body to produce heat (while shaking) in order to heat up the body

vasoconstriction: traps heat from the skin in order to bring heat to the internal part of the body.

Question 15

what is homeostasis?

Answer 15

the maintenance of a constant internal environment

Question 16

what two important substances correct glucose levels in the body?

Answer 16

glucogon and insulin

Question 17

what occurs when the glucose levels are too high in the body?

Answer 17

the pancreas stimulates and secrets the insulin to change it into glycogen (fat) - this conversion is done in the liver and muscle cells

Question 18

what occurs when glucose levels are low?

Answer 18

glucogon reverts glycogen to glucose