Excretory system & Homeostasis

Question 1

What are the labels of the excretory system

Answer 1

Renal artery
Renal vein
Kidney
Ureter
Bladder 
Urethra

Question 2

What is the function of the Bladder

Answer 2

Stores urine

Question 3

What is the function of the Ureter

Answer 3

Caries urine from the kidney to the bladder

Question 4

What is the function of the Urethra

Answer 4

Connects bladder to the outside

Question 5

Define metabolism

Answer 5

The sum of chemical reactions in the body

Question 6

Define homeostasis

Answer 6

keeping the conditions within the body constant

Question 7

Why is homeostasis necessary

Answer 7

1. To allow metabolic reactions to take place at a suitable rate.
2. To provide a suitable temp for enzymes to work properly

Question 8

Define osmoregulation

Answer 8

maintaining water and salt balance in the body

Question 9

Define excretion

Answer 9

the removal of the waste products of metabolism from the body

Question 10

Define egestion

Answer 10

the removal of the undigested materials from the body

Question 11

What controls temp in the body

Answer 11

1. metabolism (produces heat)

2. sweating (cools the body)

Question 12

What is hypothermia

Answer 12

When your core body temp drops

Question 13

What organs are involved in excretion

Answer 13

1. Kidneys: Urea, excess salts and water in urine
2. Lungs: Carbon dioxide and water in breath
3. Skin: water and salt through sweat

Question 14

What is the function of the renal artery

Answer 14

Brings impure blood from heart

Question 15

What is the function of the renal vein

Answer 15

Brings purified blood to vena cava

Question 16

What is the nephron

Answer 16

The Nephron is the Functional Unit of Kidney

Question 17

In terms of urine formation, what is filtration?

Answer 17

It occurs in the cortex.

- Blood in the arteriole is under pressure due
to narrowing of blood vessels
- Plasma and small molecules forced from
glomerulus into Bowman’s capsule
- Large molecules and blood cells cannot
pass into Bowman’s capsule as they are
too big

Question 18

In terms of urine formation, what is reabsorption?

Answer 18

1. Proximal Tubule: substances needed by the body such as glucose, vitamins, amino acids, some salts
   and water pass from glomerular filtrate back into the blood by diffusion, active transport and osmosis
2. Loop of Henle and the distal convoluted tubule: more water is reabsorbed.and salt is balanced
3. Collecting Duct: final water reabsorption under the influence of ADH (anti-diuretic hormone)

Question 19

What is diffusion

Answer 19

The movement of substances from high concentration to low concentration. It does not require energy

Question 20

What is active transport

Answer 20

The movement of substances from low concentration to high concentration. Energy is needed

Question 21

what is osmosis

Answer 21

Osmosis is diffusion of water across a semi-permeable membrane

Question 22

What happens when there is Low water concentration in blood

Answer 22

• if not enough water in blood due to sweating or salty food, more ADH (vasopressin) released
• Which allows more water to be reabsorbed into blood by the
  collecting duct
• Resulting in small amounts of strong urine

This process is monitored by medulla

Question 23

What happens when there is high water concentration in blood

Answer 23

• If too much water in blood due to drinking excess water,Less ADH (vasopressin) released
• Which allows less water to be reabsorbed into blood by the collecting duct
• Resulting in large amounts of watery urine called diuresis.

Question 24

What are endotherms

Answer 24

animals whose body temperature is constant Eg: mammals

Question 25

What are ectotherms

Answer 25

animals whose body temperature varies with environmental temperature
e.g. fish, reptiles

Question 26

What happens when the body is too cold

Answer 26

a) Hair stands erect to trap layer of insulating air
b) Arterioles leading to capillaries in the skin narrow to keep
blood flow away from skin. (vasoconstriction)
c) This reduces heat loss
d) Lack of blood near the surface makes the skin pale
e) Shiver to produce heat by muscle movement
f) There is also a layer of fat to insulate body against
heat loss

Question 27

What happens when the body is too hot

Answer 27

a) Hair lies flat, so no insulating air trapped
b) Sweat produced. Water evaporates which cools the skin
g) Arterioles leading to capillaries in the skin relax to allow blood to flow nearer the surface (vasodilatio)
c) This allows heat to escape more easily
d) Large amounts of blood near the surface makes the skin red

Question 28

Carbon dioxide levels in the blood

Answer 28

• monitored by the brain
   Used to control breathing rate
   As CO2
  levels rise the blood becomes more acidic
   This results in an increase in breathing rate and depth

Question 29

CO2 levels in plants

Answer 29

• low levels of CO2 in the air spaces in the leaf stimulate the opening of the stomata
• High levels of CO2 in the air spaces in the leaf stimulate the closing of the stomata

Question 30

What is the location of the kidney

Answer 30

The rear abdominal cavity

Question 31

The nephron’s diagram labels

Answer 31

1. Afferent arteriole: blood under pressure because of narrowing of blood vessel
2. Glomerulus: ultrafiltration under pressure removes soluble impurities
3. Bowmans capsule: collects filtrate
4. Proximal convoluted tubule: useful substances reabsorbed into capillaries
5. Efferent arteroile: blood with little plasma
6. Distal tubule: salt and water balance.
7. Collecting ducts: final salt water balance, water reabsorbed under influence of ADH
8. Capillary network: reabsorbs materials from filtrate into plasma
9. Loop of henle: salt balance happens here

Question 32

The kidneys diagram labels

Answer 32

1. Cortex: (outside) contains bowmans capsules
2. Medulla: (middle) contains PCT, Loop of Henle, DCT and collecting ducts here
3. Pelvis: (inside) Collects urine from collecting ducts