Osmoregulation Flashcards
Whats the pituitary gland ?
- The pituitary gland is a pea-sized structure located at the base of the brain, below the hypothalamus, to which it is attached via nerve fibres.
- It is part of the endocrine system and produces critical hormones.
- All vertebrates have one.
Whats the 2 sections of the pituitary gland which each secrete their own hormones?
Anterior gland and posterior gland
3 hormones secreted by anterior gland are…
GH – Growth Hormone - bones
ACTH – adrenal stimulating
LH – lutinising hormone – lining of womb/stimulates testosterone
2 hormones secreted by posterior gland are…
Oxytocin – Stimulates uterus to contract during childbirth and releasing milk from ducts
ADH – Kidneys – prevents water loss
Define osmoregulation
Osmoregulation is the process by which organisms regulate the water content of the body.
What happens if theres an increase in water potential?
1)normal water potential of blood
2)increase in water potential
3)change detected by osmoreceptors in the hypothalamus
4)pituitary gland releases less ADH
5)Decrease in permeability of collecting ducts - less water reabsorbed
6)dilute urine
…in order to EXPEL excess water
What happens if theres an decrease in water potential?
1)normal water potential of blood
2)decrease in water potential
3)change detected by osmoreceptors in the hypothalamus
4)pituitary gland releases more ADH
5)ADH increases permeability of collecting ducts
6)concentrated urine
…in order to CONSERVE water
Whats urea?
Urea is a waste product that is made when the LIVER breaks down proteins that are not needed by the body.
Urea contains the element Nitrogen.
Whats the function of the kidneys? 1
The kidneys “clean” the blood of waste products and control how much water is kept in the body. The waste products and water make up urine which is excreted via the ureter and then stored in the bladder.
“Dirty” blood enters the kidney through the renal artery. Then, several things happen to clean the blood… After which, clean blood leaves the kidney via the renal vein
Whats the order of the nephron process?
1) Ultrafiltration
2) Selective rebsorbtion
3) Excrete the waste
What happens in ultrafiltration?
1) Blood enters the tubule area in a capillary.
2) The capillary forms a small “knot” near the kidney tubule called the glomerulus.
3) The blood is filtered so all the small particles go into the tubule.
4) The capillary then carries on to run next to the tubule.
5) The kidney tubule now contains lots of blood components including:
- glucose
- ions
- water
- urea
What happens during selective reabsorption?
Reabsorb sugar:
The body needs to have glucose in the blood for cells to use in respiration. So all the glucose is reabsorbed back into the capillary.
Reabsorb water:
Water and ions are the next to be absorbed. It depends on how much is needed by the body.
What happens in the excrete waste stage?
Everything that is left in the kidney tubule is waste:
- All the urea
- Excess water
This waste is called urine. It is excreted via the ureter and is then stored in the bladder.
The “clean” blood leaves the kidney in the renal vein.
Whats adh do?
ADH controls the ability of water to pass through the cells in the walls of the collecting ducts.
If no ADH is present, then no water can pass through the walls of the ducts.
If the Na concentration of the blood is low, ADH is not secreted.
Wheres ultrafiltration occur?
Bowmans capsule
Wheres selective reabsorption occur?
Proximal convoluted tubule
and
distal convoluted tubule
whats adh stand for?
antidiuretic hormone (ADH)
What are the kidneys ?
The kidneys are essentially blood filters.
Blood is brought to the kidneys to be filtered by the Renal Artery. After filtering, the blood is taken away again by the Renal vein.
What are the functions of the kidneys?
The kidneys have four functions:
Filter your blood.
Remove excess water from your blood, but conserve water when needed.
Remove excess mineral ions from your blood but conserve them when needed.
Remove urea from your blood.
What do osmoreceptors do?
Osmoreceptors in the hypothalamus monitor the water potential of the blood. This varies the amount of antidiuretic hormone (ADH) released into the bloodstream.
Whats nephrotic syndrome?
An autoimmune disorder where there is a change in the glomeruli. They become more leaky, and so some proteins pass
through, leaving the body in urine. The main protein that leaks out is albumin which is quite a small protein and more
likely to leak through the glomeruli. Albumin helps keep fluid in the blood
Symptoms of nephrotic syndrome?
Oedema –Tissue Swelling
High Fat levels in blood
Low thyroid hormone levels
Blood Clots
Tired , Decreased appetite, Nausea/Diarrhoea, Pain in the abdomen.
How do we monitor nephrotic syndrome?
Urine Tests – Dipstick
Blood Tests
Imagining Tests (Ultrasound, Chest X-Ray)
Kidney Biopsy
Regular Hospital trips and check ups
How do we treat nephrotic syndrome?
Low Salt Diet (High sodium can cause high blood pressure, increase pressure in kidneys)
Steroid Treatment (Can increase risk of infection)
Kidney Failure = Transplant or Dialysis (12 hours on machine/ 3 times a week)
How does kidney dialysis work?
In the absence of a suitable kidney donor, kidney dialysis is used
The patient needs to be on the machine for around 12 hours, repeated three times a week.
The patient needs to be careful what they eat & drink. Too much salt & protein between dialysis treatments can cause problems. Also the amount of fluid which may be taken is very restricted, as the body has no way of getting rid of it.
Define negative feedback loop.
When the body responds to a negative change to bring it back to normal values.
Define hypertonic
Blood with too low a water potential and high in solutes
Define hypotonic
Blood with too high a water potential and low in solutes
