excretory system

Question 1

What is Excretion?

Answer 1

Excretion is the process of removing metabolic wastes, toxic substances, and substances in excess (more than what the body needs such as e.g. water and salt) from the body.

Question 2

Define the term metabolic waste

Answer 2

Metabolic wastes are substances left over from metabolic processes which cannot be used by the organism, and must therefore be excreted

Question 3

What is metabolism

Answer 3

Metabolism is the chemical reactions in the body’s cells that change food into energy.

Question 4

What is the goal of Excretion

Answer 4

Goal of Excretion: Maintain homeostasis!!

Question 5

What is Homeostasis?

Answer 5

-the process that maintains a constant internal environment in a living organism

Question 6

What are the conditions that need to be maintained

Answer 6

• Amount of water in the body ( water concentration)
• Amount of carbon dioxide (CO2 concentration)
• Amount of salts
• Body temperature
• blood glucose levels

Question 7

What are the metabolic wastes ?

Answer 7

• waste products are CO, nitrogen compounds and salt

1. CO, produced during cellular respiration (in addition to water)
2. Nitrogen compounds - urea -produced by the breakdown of amino acids (obtained when protein is digested) in process of deamination that occurs in the liver, and other nitrogenous waste in very small amounts such as ammonia, uric acid.
3. Salts produced by metabolism

urea, salt, and water

Question 9

What are the parts of the excretory system?

Answer 9

Kidneys, ureter, urethra, and bladder

Question 10

What are the functions of the kidneys

Answer 10

• remove waste products from blood
• maintain blood pH
• control water content of blood (osmoregulation)

Question 11

What does the lungs excrete and How is it removed

Answer 11

• carbon dioxide and it is removed as Gas in expired air.
• Excess water is removed as Water vapor in expired air

Question 12

What does the kidneys excrete and how is it removed?

Answer 12

1. excrete Urea( from deamination of excess amino acids in the liver) it is removed by urine
2. Mineral salts
3. Uric acid fron breakdown of nucleic acid
4. Creatinine from breakdown of muscle tissue.
5. Excess lungs

( all is removed by urine)

Question 13

What does the skin excrete and how is it removed?

Answer 13

The skin excretes water, salts, urea (small amounts) and heat and it is removed by the sweat glands that excrete water and some urea, helps regulate heat loss.

Question 14

What does the liver excrete and how is it removed?

Answer 14

The liver excretes Bile pigments and it removed through the faeces

Question 15

How does the Excretory system work

Answer 15

1. Blood enters kidneys from renal artery
2. Blood is filtered by passing through millions of nephrons
3. Wastes pass through ureter to the bladder as urine
4. Clean blood returns to body through renal vein
5. Bladder stores urine and passes urine out of the body through the urethra

Question 16

What are the Nephrons and ehat does it produce?

Answer 16

Nephrons (or Kidney Tubule): The functional unit of the Kidney that make urine in the body.

These long coiled tubes are where the blood is actually filtered and urine is produced