Excretion / Homeostasis /

Question 1

Give four ways that water is removed from the body

Answer 1

• urine
• sweat
• faeces
• exhaling

Question 2

Give one difference between composition of tissue fluid and composition of blood

Answer 2

Tissue fluid lacks plasma proteins

Question 3

Give three examples of things the body controls

Answer 3

• carbon dioxide levels
• blood ph
• body temperature

Question 4

What is tissue fluid

Answer 4

Watery solution of salts, glucose and solutes that acts as a pathway to transport nutrients between the blood and cells

Question 5

Explain what would happen to the cells if the tissue fluid had too many solutes

Answer 5

Water would flow out of cells through osmosis, from a more dilute solution, to a less dilute solution, and would become crenated

Question 6

Give two examples of nitrogenous waste

Answer 6

Urea and ammonia

Question 7

Explain the difference in how carbohydrates and fats are stored by the body, and how protein is stored by the body

Answer 7

Carbohydrates and fats are either stored in the liver or as fat, surrounding organs
Protein can not be stored so is broken down into amino acids by the liver,
and converted into carbohydrates (stored as glycogen)
And nitrogenous waste product urea is formed

Question 8

Difference between excretion and egestion

Answer 8

Egestion is the removal of undigested food from the body

Excretion is the removal of metabolic waste products from the body

Question 9

Difference between ureter and urethra

Answer 9

Ureter transports urine from the kidney to the bladder

Urethra transports urine from bladder to body’s exterior

Question 10

Role of sphincter muscles

Answer 10

Contract and relax to control flow of urine out of the urethra

Question 11

Describe which two blood vessels take blood to the kidney and which two blood vessels take clean blood back to the heart

Answer 11

From the aorta, the renal artery takes unfiltered blood to the kidney
And then the renal vein takes filtered blood back to the vena cava of the heart

Question 12

Give two reasons why the glomerus has high blood pressure

Answer 12

• the renal artery has a thick muscular wall which is able to contract and expand, increasing the pressure
• because of the contraction of the left ventricle

Question 13

Where exactly in the kidney are nephrons located

Answer 13

Located in the cortex

Question 14

Fill in the blanks
The lighter outer region of the kidney is called the…..
The inner darker region of the kidney is called the…

Answer 14

Cortex

Medulla

Question 15

Where does ultrafiltration take place

Answer 15

In the bowman’s capsule

Question 16

Give names of the three layers between the glomerulus and the bowman’s capsule

Answer 16

Capillary wall
Basement membrane
wall of capsule

Question 17

What happens to the other 99% of glomerular filtrate that is not filtered through the capsules

Answer 17

It is reabsorbed back into the blood

Question 18

Where does selective reabsorbtion take place

Answer 18

In the tubule of the kidney

Question 19

Which part of the tubule is in the medulla

Answer 19

The loop of Henlie

Question 20

Why does the flow rate (concentration of water) decrease from the bowman’s capsule to the first part of the tubule

Answer 20

Because some water is absorbed back into the blood

Question 21

How is the nephron adapated for ultrafiltration of glucose molecules

Answer 21

Contains many mitochondria to provide energy for active transport of glucose molecules

Question 22

why does urea concentration increase from glomerular filtrate to tubule

Answer 22

water concentration decreases as is it absorbed back into blood through osmosis, so urea is more concentrated

Question 23

Why are kidney transplants often placed in lower abdomen rather than next to other kidney

Answer 23

Because it is closer to the bladder and other major blood vessels

Question 24

Explain why desert animals have concentrated urine

Answer 24

They have long loops of Henlie
Thus more water is reabsorbed into the blood to conserve water
And so concentration of urea is more

Question 25

Which capillaries supply the arteries of the glomerus?

Answer 25

Arterioles

Question 26

Explain what happens when you are dehydrated

Answer 26

1) receptors in the hypothalamus of the brain detect a change in the concentration of water in the blood 2) so they release more anti diuretic hormone from the pituatory gland 3) this travels to the kidney through the blood and makes the collecting duct more permeable to water, so more water is reabsorbed back into the body 4) so urine produced is very concentrated and in a small volume

Question 27

Explain what happens when you have drunk too much water

Answer 27

1) receptors in the hypothalamus of the brain detect a change in the concentration of water in the blood 2) so they release less anti diuretic hormone from the pituatory gland 3) this travels to the kidney through the blood and makes the collecting duct less permeable to water, so less water is reabsorbed back into the body 4) so urine produced is very dilute and in a large volume

Question 28

The kidney carries out two functions in the human body, state these functions

Answer 28

Osmoregulation | Excretion

Question 29

A kangaroo rat has a high concentration of ions in the tissue around the collecting duct. Explain how this helps it to survive in the desert

Answer 29

High concentration of ions means it has a lower concentration of water in the tissue Therefore water from collecting duct will move from a high concentration to a low concentration through a semi permeable membrane through the process of osmosis And so more water will be absorbed into the body and urine will be less concentrated

Question 30

Suggest where a kangaroo rat can get water from their body from

Answer 30

Through the process of respiration

Question 31

Which part inside of a kidney is the bowman’s capsule located

Answer 31

Located in the cortex | Although some of the nephron is in the medulla like the loop of henle

Question 32

Where is urea produced

Answer 32

In the liver

Question 33

What is meant by the term Osmoregulation

Answer 33

The maintenance of the balance of water going into the body and water going out of the body

Question 34

Describe how glomerular filtrate is produced in the body (3)

Answer 34

Blood enters the glomerus from the renal artery which comes from a very high pressure Which helps to filter only the small molecules through Into the bowman’s capsule to form the glomerular filtrate

Question 35

A runner went for a 10 mile jog on a hot day Her urine was darker than usual when she returned Explain why she produced darker colour urine(6mark)

Answer 35

1) water was lost from her body due to the heat as she was sweating 2) so osmorecpeptros in hypothalamus detected a change in water levels and signaled the pituitary gland to release more ADH 3) The collecting duct was now more permeable and more water could be reabsorbed into the body 4) so the urine contained less water and so was more concentrated and thus darker in colour

Question 36

What is the EFFECT of ADH on the body

Answer 36

It increases the permeability of the collecting duct to absorb more water and releases more concentrated urine ( when they ask for effect they’re not asking for its role. It’s role would be to control the water levels. But effect is when it is secreted what it actually does)

Question 37

Which blood vessel does the cleaned blood flow through

Answer 37

The renal vein

Question 38

Give 5 substances that are filtered into the bowman’s capsule

Answer 38

``` Glucose Urea Water Ions Amino acids ```

Question 39

Give 4 substances that are reabsorbed into the tubules

Answer 39

All glucose Some ions Some water All amino acids

Question 40

Give three substances that are present in the urine

Answer 40

Water Urea Excess Ions

Question 41

Why is it better to connect a vein to a kidney machine instead of an artery Give two reasons

Answer 41

Vein has less pressure | Veins are closer to the surface so easier to see

Question 42

What is an artériole

Answer 42

Blood vessel that connects arteries to the capillaries

Question 43

State which parts of the nephron are located in which parts of the kidney

Answer 43

Proximal and distal convoluted tubule are inside the cortex Loop of henle and collecting duct are inside the medulla