2. Homeostasis Pt 5

Question 1

What does Urine contain?

Answer 1

• mostly water, with varying amounts of slats & urea dissolved in it
• these are all colourless
• but the yellow part of the urine is due to urobilins which are created by the liver as it breaks down haemoglobin

Question 2

Quickly go through the the states urea goes through to be turned into urine?

Answer 2

1. Urea is made the liver
2. Flows in the blood
3. Urea, ions, glucose and water pass into kindness tubules
   (Glucose, some ions and some water is reabsorbed)
4. Urea, some ions and some water flows down ureters
5. Urine is stored in the bladder
6. Urine is expelled out of urethra

Question 3

What substances are present in blood?

Answer 3

1. Cells
2. protein
3. Glucose
4. Water
5. Mineral ions
6. Urea

Question 4

What substances are present in kindness tubules?

Answer 4

3. Glucose
4. Water
5. Mineral ions
6. Water

Question 5

What substances are present in urine?

Answer 5

4. Some water
5. Some mineral ions
6. Urea

Question 6

Where is ADH produced?

Answer 6

It’s produced by the pituitary gland

Question 7

What does ADH stand for and what does it do?

Answer 7

• anti-diuretic hormone
• it increases the permeability of the kidney tubules
• it will increase the amount of water re-absorbed back into the body

Question 8

Explain what happens in your body when you become dehydrated

Answer 8

1. Hypothalamus detects high concentration of solutes in blood.
   (Hypothalamus creates the feeling of thirst)
2. Pituitary gland releases ADH
3. kidneys maintain blood water level high.
   (By retaining water and making Urine more concentrated with salts and urea)(when the person drinks water)
4. So less water is lost in urine (urine is more concentrated)
5. Blood water level returns to normal

Question 9

What happens your water levels are too high?

Answer 9

1. Hypothalamus detects low solute concentration
2. Pituitary releases less ADH
3. Kindness reabsorbs less water

Question 10

What 4 things cause kindness failure?

Answer 10

-Genetic diseases
-infections
-drugs/poisons
-physical damage
This can lead to dangerous toxins to build up and your salt and water balance will be disrupted

Question 11

What are the 2 solutions to kidney failure?

Answer 11

• transplant

- kidney dialysis (this is a temporary solution)

Question 12

How does a kidney dialysis work?

Answer 12

• blood is sent to a partially permeable artificial membrane
• this prevents blood cells and large proteins from leaving the blood but allows small, soluble molecules to move freely
• the fluid around the membranes has no urea in it creating a steep concentration gradient and causing urea to diffuse out of the blood
• the dialysis fluid also has the correct concentration of glucose, ions and water which will diffuse either way until the blood reaches the right levels

Question 13

What are disadvantages of the kidney dialysis?

Answer 13

• it takes approx 8 hours to complete and is usually done in hospital 2 or 3 times a week
• this can be very disruptive for your normal life

Question 14

How does a kidney transplant work?

Answer 14

• its taken from an appropriate donor

- and attached to the blood vessels and ureter of the patient

Question 15

What’s the risk of kidney transplants? How is this risk reduced?

Answer 15

• every person has different antigens on the surface if their cells
• the immune system of the recipient may attack the new kidney, causing it to be rejected and destroyed
• this is reduced by matching donors abs recipients are closely as possible by checking they’re blood type and if they have similar surface antigens

Question 16

What happens if the surface antigens of the transplanted kidney are too dissimilar?

Answer 16

-the body’s white blood cells will produce antibodies that bind to and destroy the cells of the donated kidney

Question 17

What can the patient do to reduce the risk of rejection?

Answer 17

-take immunosuppressants drugs to reduce the immune response so that the kidney is accepted

Question 18

What are the advantages of kidney transplant?

Answer 18

• no longer needing regular dialysis sessions making life easier
• no longer needing a controlled diet
• cheaper then long-term dialysis

Question 19

What are the disadvantages of kidney transplant?

Answer 19

• require drug treatment for the rest of your life
• kidney rejection may occur
• regular check-ups needed
• limited availability of kidneys
• average kidney only works for around 9 years (but can be longer)

Question 20

What’s xenotransplants?

Answer 20

• is organs from other animals

- research into xenotransplants or using stem cells to grown organs could reduce the shortage of kidneys

Question 21

What are primary sexual characteristics?

Answer 21

• ones you’re born with

- ovaries in girls and testes in boys

Question 22

What are secondary sexual characteristics?

Answer 22

• they’re stimulated by the release of oestrogen from the ovaries or testosterone from the testes
• during puberty reproductive hormones cause secondary sex characteristics to develop

Question 23

List all 7 secondary sexual characteristics in females?

Answer 23

• growth spurt
• growth of pubic and underarm hair
• external genitalia
• eggs start to mature each month in the ovaries until they run out (menopause)
• deposition of fat on hips, buttocks and thighs
• the brain changes and matures
• the uterus grows becomes active and mensuration starts

Question 24

List all 7 secondary sexual characteristics in males?

Answer 24

• growth spurt
• growth of pubic, underarm and facial hair
• external genitalia grows
• sperm production begins in the testes and continues for life
• increased muscle development broader chest and shoulders
• the brain changes and matures
• the larynx gets bigger and the voice breaks

Question 25

What’s the menstrual cycle?

Answer 25

- a 28 day sequence to control a woman’s ability to support a developing baby - it’s controlled by 4 main hormones

Question 26

What does FSH do?

Answer 26

1. Follicle stimulating hormone (FSH) is secreted by the pituitary gland in the brain - it makes the egg start to mature in the ovaries - it also stimulates the ovaries to secret oestrogen

Question 27

What does oestrogen do?

Answer 27

2. Oestrogen is released by the ovaries - it causes the lining of the womb (uterus) to thicken, ready to receive a fertilised egg - it stops further FSH production - it triggers LH to be released by the pituitary gland

Question 28

What’s LH?

Answer 28

3. Luteinising hormone | - LH from the pituitary gland stimulates the mature egg to be released from the ovary (ovulation)

Question 29

What’s progesterone?

Answer 29

4. It’s produced in the ovaries by the remains of the follicle after ovulation - maintains the lining of the uterus during the second half of the cycle. When the level of progesterone falls the lining breaks down - it stops the release of LH and FSH

Question 30

What are the 4 stages of the menstrual cycle?

Answer 30

Stage 1-mensuration starts. The uterus lining breaks down for about 4 days Stage 2- the uterus lining builds up again from day 4 to 14, into a thick layer full of blood vessels, ready to receive a fertilised egg Stage 3- an egg develops and is released from the ovary on day 14 (this is called ovulation) Stage 4- the wall is then maintained for about 14 days until day 28. If no fertilised egg lands on the uterus wall by day 28. The spongy lining breaks down and the whole cycle starts again