B12 Excretion in Humans T16

Question 1

Define excretion

Answer 1

removal of waste products and toxic substances from the body

Question 2

3 human organs of excretion

Answer 2

1. lungs
2. skin
3. kidneys

Question 3

What do organs excrete?

Answer 3

1. Lungs - carbon dioxide
2. skin - excess water and salts -> sweat
3. kidneys - excess water, urea and ions and salts

Question 4

How and where is urea produced?

It’s formed in the ____ from the breakdown of unecessary ____________ in the body. It travels in the ____ and is removed by the kidneys

Answer 4

1. liver
2. amino acids
3. blood

Question 5

How and where is urea produced?

It is produced by respiring ____ and is transported by the ____ to the lungs where it’s excreted.

Answer 5

1. tissues
2. blood

Question 6

structure of urinary system

Answer 6

● The inner part of the kidney is called the medulla and the outer part is called the cortex.
● The ureter carries from kidneys to the bladder to be excreted out the body.
● The kidney is supplied by the renal artery and a renal vein takes blood away.
● Each kidney contains millions of kidney tubules or nephrons

Question 7

Order of the urinary system

Answer 7

1. kidney
2. ureter
3. bladder
4. urethra

Question 8

Describe the structure of the urinary system

Answer 8

• The inner part of the kidney is called the medulla and the outer part is called the cortex.
• The ureter carries from kidneys to the bladder to be excreted out the body.
• The kidney is supplied by the renal artery and a renal vein takes blood away.
• Each kidney contains millions of kidney tubules or nephrons

Question 9

renal artery

Answer 9

oxygenated blood to the kidney

Question 10

renal vein

Answer 10

deoxygenated blood out of the kidney

Question 11

ureter

Answer 11

takes urine from kidneys to bladder

Question 12

urethra

Answer 12

tube that carries urine out the body during urination

Question 13

What do the kidneys do?

Answer 13

filters blood
makes urine

Question 14

Urine

Answer 14

watste product of kidney
contains:
1. excess water
2. urea
3. ions (salts)

Question 15

What 3 functions does the nephron do?

Answer 15

1. ultrafiltration
2. selective reabsorption
3. osmoregualtion

Question 16

Order of nephron

Answer 16

1. glomerulus
2. Bowman’s capsule
3. first convoluted tubule
4. goes through cortex to medulla
5. loop of Henle
6. out of medulla into cortex
7. second convoluted tubule
8. collecting duct
9. ureter

Question 17

Describe the process of ultrafiltration in the glomerulus

Answer 17

1. renal artery transports oxygenated blood under high pressure to glomerulus through arterioles
2. fluid (filtrate) from blood forced through walls of capillaries into Bowman’s capsule
   3.

Question 18

Why is there a wider dimater of the arteriole entering the golmerulus, compared to the arteriole leaving

Answer 18

to produces a high pressure in the glomerulus -> forces the fluid from blood into the capillaries of Bowman’s capsule
ULTRAFILTRATION -> water, salts, glucose, urea

Question 19

what is ADH and what does it do

Answer 19

released into the pancreas by the pituitary gland when a receptor in the brain detects that the blood is too concentrated

● It travels in the bloodstream to the kidney tubules
● An increased amount of ADH reaching the tubules increases their permeability to water,
so more moves out of the tubule and back into the bloodstream
● This results in a smaller volume of more concentrated (yellow) urine and the blood becoming less concentrated as more water moves into it

little water in blood - adh released, more water absorbed by kidneys, less water lost in urine, blood water returns to normal level

too mcuh water in blood - adh released, less water absorbed by kidneys, more water lost in urine, blood water returns to normal level

Question 20

on a hot day, explain levels of sweat and urine

Answer 20

lots of sweat - leads to dehydration, leads to salt loss, so kidneys make up for it by increasing how much salt the body keeps - makes us thirsty and drink more
barely any urine

Question 21

explain why protein and glucose are found in blood plasma but not in urine

Answer 21

protein - too large to pass through filter, not absorbed
glucose - passes through kidney filter and is reabsrobed