3.7 Homeostasis And The Kidney

Question 1

Explain negative feedback

Answer 1

A change in a system produces a second change, which reversed the first change

Question 2

Give an example of negative feedback

Answer 2

Glucose concentration in the plasma

Body temperature

Question 3

Explain the stages of negative feedback

Answer 3

The set point for a factor is the norm at which a system operates

A receptor detects that level of the factor has changed

The receptor sends instructions to a co-ordinator or controller

To co-ordinator communicates with one or more effectors, which makes responses that are corrective procedures.

The factor returns to normal, monitored by the receptor and information is fed back to the effectors, which stop making the correction.

Question 4

Give examples of positive feedback

Answer 4

Giving birth

Clot formation

Question 5

Define osmoregulation

Answer 5

The control of the water potential of the body’s fluids by the regulation of the water content of he body

Question 6

How are carbon dioxide and water excreted

Answer 6

In respiration the compounds are excreted in expired air out of the lungs

Question 7

How is urea excreted

Answer 7

Urea is produced in the break down of amino acids, and excreted in urine. The excretory gland is the kidney.

It is also produced when sweating and is excreted in sweat through the skin

Question 8

How is creative produced and secreted

Answer 8

Produced in muscle tissue breakdown. Excreted in urine, excretory gland is the kidney.

Question 9

How is uric acid produced and excreted

Answer 9

Produced in nucleic acid breakdown. Excreted in urine through the kidney.

Question 10

How are bile pigments produced and excreted

Answer 10

Produced in haemoglobin breakdown and excreted in faeces using the liver

Question 11

What are the two main functions of the kidney

Answer 11

Excretion and osmoregulation

Question 12

What are 3 ways of excreting water

Answer 12

Metabolic waste as a product of respiration

secreted in tears and saliva

Egested in faeces

Question 13

Define excretion

Answer 13

The removal of nitrogenous metabolic waste from the body

Question 14

Define osmoregulation

Answer 14

The control of the water potential of the body’s fluids (plasma, tissue fluid and lymph) by regulating the water content, and therefor the solute concentration.

Question 15

Give the chemical equation showing be production of urea

Answer 15

CHR.NH2.COOH
Amino acid 
             |
O=CHR.COOH + NH3
A-keto acid  +  Ammonia 
             |
O=C(NH2)
Urea

Question 16

CHR.NH2.COOH
Amino acid 
             |
O=CHR.COOH + NH3
A-keto acid  +  Ammonia 
             |
O=C(NH2)
Urea

What is this process called

Answer 16

Deamination

Question 17

How and why are amino acids produced

Answer 17

Dietary proteins are digested to amino acids. These are transported to the liver and then around the body where they are assimilated into proteins

Question 18

What happens to waste amino acids

Answer 18

Excess amino acids are deaminated in the liver and the amino group is converted to urea

Question 19

Name the blood vessels that deliver blood to and from the kidney

Answer 19

TO = The renal artery
FROM = the renal vein

Question 20

Name the tough capsule that covers the kidney

Answer 20

The renal capsule

Question 21

What carries urea from the kidneys to the bladder

Answer 21

The ureter

Question 22

Where are kidneys located?

Answer 22

Either side of the vertebral column

Question 23

Hat is the outlet layer of the kidney called

Answer 23

The cortex

Question 24

What parts of the kidney are contained in the medulla

Answer 24

Loops of Henle

Collecting duct

Question 25

What part of the kidney is in the cortex

Answer 25

Efferent arteriole
Glomerulus 
Afferent arteriole 
Proximal convoluted tubule
Bowman’s capsule
Distal convoluted tubule