5. Homeostasis and Response (the kidneys)

Question 1

What are the functions of the kidneys?

Answer 1

• remove urea
• regulate ion levels
• regulate water levels

Question 2

What is deamination?

Answer 2

When excess amino acids are converted into lipids or carbohydrates, which can be stored as an energy source for later. This process also produces urea, which has to be excreted by the kidneys

Question 3

Where does deamination take place?

Answer 3

in the liver

Question 4

What 3 things are lost from the skin by sweat?

Answer 4

• water
• ions
• urea

Question 5

What is the two ways that water is lost from the body?

Answer 5

• via the lungs exhalation
• sweating

Question 6

Do the lungs and the skin have control over water, ion or urea loss?

Answer 6

no

Question 7

If there is too much water in the body, what could happen to our cells?

Answer 7

• the water could enter our cells by osmosis
• causing them to swell up and possibly even burst

Question 8

What are the millions of tiny units in the kidneys called?

Answer 8

nephrons

Question 9

What is filtration or (ultrafiltration) in the kidneys?

Answer 9

as blood passes through the kidneys, small substances like glucose, amino acids, and water are absorbed from the blood into the kidneys

Question 10

What is selective reabsorption in the kidneys?

Answer 10

the process whereby certain molecules are reabsorbed from the filtrate, as it passes through the nephron

Question 11

Which hormone is responsible for regulating water levels in the body?

Answer 11

Antidiuretic hormone (ADH)

Question 12

Which part of the brain detects the level of water in the body?

Answer 12

hypothalamus

Question 13

How does blood enter and leave the kidneys?

Answer 13

blood enters the kidneys via the renal arteries and leaves via the renal veins

Question 14

How does the body respond to low water levels?

Answer 14

1. The hypothalamus detects the low concentration of water in the bloodstream.
   2.This causes it to send a signal to the pituitary gland, which tells it to release more antidiuretic hormone (ADH).
   3.The ADH travels around the body in the blood, and stimulates the kidneys to reabsorb more water from the tubules into the blood.
2. so less urine will be made, and the concentration of water in the blood rises.

Question 15

Which structure carries the urine, from the bladder, out of the body?

Answer 15

the urethra

Question 16

True or false. Selective reabsorption takes place throughout the nephron?

Answer 16

true

Question 17

How much glucose and proteins are reabsorbed back into the blood?

Answer 17

almost all

Question 18

How much water and ions are reabsorbed back into the blood?

Answer 18

it depends on how much is already in the blood

Question 19

How much urea is absorbed back into the blood?

Answer 19

none