Hormonal Flashcards
Homeostasis for blood composition
The amount of water reabsorbed from the filtrate back into the blood influences two characteristics of blood
It’s blood volume, which is between 4 to 6 L
It’s plasma solute concentrations which is normal levels of salts ions, etc.
These characteristics must remain constant despite changes in environmental conditions, such as amount of water, consumed amount of salt, amount of perspiration, etc.
Osmoreceptors
Special receptors called Osmo receptors are found in the hypothalamus of the brain these receptors pick up changes and solute concentration of the blood if the Osmo receptors pick up changes and saw your concentration, they sent a signal to the pituitary gland, the pituitary gland releases, anti-dicrectic hormone ADH in response to changes in solute concentration.
ADH
Is a hormone released in the pituitary gland (because of Osmoreceptors ) antidiuretic hormone ADH in response to changes in solute concentration
The ADH travels where and what it does
Travels to the distal tubule and the collecting duct causing these tubules to become more permeable to water
In the influence of ADH more water will be absorbed back into the blood diluting it and retaining water in times of water loss
ADH response order
Osmoreceptors in hypothalamus detect high solute concentration in. Blood
Pituitary gland receives message from hypothalamus and secretes ADH
ADH increases permeability of tubule walls to water= urine becomes more concentrated
Blood becomes more diluted, ADH production is stopped
Diabetes insipidus
Is a disease in which ADH production is lower than it should be
The individuals kidneys are not transporting water from the filterate
As a result the volume of water released by urination greatly increases
Blood volume and pressure
Blood volume influences blood pressure and affects health of the cardiovascular system
Solute concentration remains relatively constant
If we drink too much, kidneys allow more water to pass into urine
If water is scarce, kidneys conserve water and concentrate urine
If we take in too many salts kidneys allow for more to pass through the urine or take in water to compensate
Aldosterone
Is a hormone produced by the adrenal gland, and it affects the permeability of nephrons to salts
It is secreted in response to low blood pressure detected in the afferent arteriole
By absorbing ions, solute levels of the plot increase which draws water back into the blood through osmosis
As water flows back into the blood, the volume of the blood increases, which causes the pressure to increase
Hypertension
Hypertension is the leading cause of kidney failure high blood pressure can cause the delicate filters of the nephron to become damaged resulting in blood, not being filtered and water not being reabsorbed
Maintaining blood pH
Bicarbonate ions act as a buffer to regulate blood pH blood pH should be 7.4 if blood is too acidic kidneys will H plus ions and reabsorb HCO if blood is too alkaline H plus is not secreted and HCO is not reabsorb
Kidney Failure
High blood pressure reduced blood, flow, diabetes, or poisoning can cause damage to nephrons
Nephrons can regenerate, but overtime may become permanently damaged
Solution one is dialysis, which is a filter connected to a person’s artery and vein to filter blood via an external artificial kidney
Solution two is a kidney transplant. A donor with matching markers provides a kidney to a patient. The donor may be alive or recently deceased
ADH response reverse
The reverse occurs if blood solute concentration is too low. ADH secretions are prevented and more water is excreted in the urine.
If blood is too diluted Osmoreceptors stop the release of ADH
Distal tubule and collecting duct become less permeable to water and salts
Hemodialysis
Kidney outside body
Peritoneal dialysis
Kidney inside body
