Chapter 9.3 Flashcards
What does the water reabsorbed from filtrate do?
Influences 2 important characteristics of blood
What 2 things does water reabsorbed from filtrate influence in blood?
Its volume and its concentration of plasma solutes
What is osmotic pressure?
The force generated as water moves by osmosis
What does blood volume influence?
Blood pressure and thus the health of the cardiovascular system
How is the concentration of solutes in the blood affected by water?
It is not affected by the amount of water ingested. It remains constant
What does the body do in response to the amount of water taken in by the body?
If water is scarce the kidneys conserve water by producing concentrated urine
If water is plentiful the kidneys allow more water to pass into the urine
What are osmoreceptors?
Cells that are sensitive to osmotic pressure
Where are osmoreceptors found?
In the hypothalamus
What is the hypothalamus?
The part of the brain that regulates hunger, thirst, blood pressure, body temperature, fluid balance, and salt balance. Or the part of the body that regulates homestasis
What happens to osmotic pressure when blood plasma becomes too concentrated (dehydration)?
Osmotic pressure increases
What happens in the hypothalamus in response to an increase in osmotic pressure?
Osmoreceptors in the hypothalamus send impulses to the pituitary gland that causes the release of an antidiuretic hormone
What does the antidiuretic hormone released by the pituitary gland do?
Inhibits the excretion of urine by traveling through the blood and to the kidneys by increasing the permeability of the distal tubule and collecting duct.
What does the increase of permeability of the distal tubule and collecting duct do?
Allows more water to be reabsorbed into the blood
What happens when more water is reabsorbed into the blood?
It dilutes the blood and lowers osmotic pressure to normal
What happens to osmoreceptors if blood plasma is to dilute?
They stop or prevent the release of ADH by making the distal tubule and the collecting duct less permeable to water
What happens when the distal tubule and the collecting duct is less permeable to water?
It allows more water to be excreted in urine concentrating solutes in the blood
When happens when the solutes in the blood become concentrated enough for the body?
The osmotic pressure of plasma and tissue fluids rise to normal
What is diabetes insipidus?
A condition where ADH activity is insufficient and a person urinates excessively
What happens as a result of diabetes insipidus?
Thirst is intense but water is excreted more quickly than consumed
What does diabetes insipidus lead to?
Severe dehydration and ion imbalances
What is the treatment for diabetes insipidus?
Taking synthetic ADH
What is an example of a common diuretic?
Ethanol in alcoholic beverages
How does alcohol stimulate urine production?
By increasing water loss through urination by decreasing ADH release which decreases permeability of tubules and collecting ducts
What does drinking an alcoholic beverage do to thirst?
Because it increases water loss to urine it intensifies thirst which leads to dehydration
How do the kidneys regulate salt balance in the blood?
By controlling the excretion and reabsorption of ions
What is the most abundant ion in the plasma?
Sodium ion
What is a drop in sodium ion concentration compensated by?
The kidneys under the influence of the hormone aldosterone
What does aldosterone do?
Stimulates distal tubule and collecting ducts to reabsorb the sodium ions
What is the reabsorption of sodium ions followed by?
Chloride ions and water
What is the net effect of aldosterone?
it retains salt and water because when it is reabsorbed water follows
How does aldosterone affect potassium ions?
It stimulates the secretion of potassium ions into the distal tubules and collecting ducts if concentration in the blood is too high
What is the regular pH of the blood?
7.4
How does the acid base buffer system prevent changes in the body’s pH?
By adding or removing hydrogen
What do the key reactions in the acid base buffer system involve?
Carbonic acid and bicarbonate ions
What does an increase in H+ do to the body’s pH?
Decreases the pH
Which reaction helps to prevent major changes in blood pH?
The reaction of carbonic acid to bicarbonate ions and H+ or the reaction of carbonic acid to water and carbon dioxide
What is the acid base buffer reaction aided by?
An increased breathing rate that pulls the reaction of carbonic acid to produce CO2 quicker
What is the reaction of the acid base buffer system?
H + HCO3← → H2CO3← → H2O + CO2
pH increases ← → pH decreases
What are the mechanisms of acid base control aided by?
The mechanisms of the kidneys
What happens if the blood is too acidic in the kidneys?
H+ is excreted and HCO3 is reabsorbed in the kidneys
What happens if the blood is too basic in the kidneys?
H+ is not excreted and HCO3 is not reabsorbed
What does the composition of urine reflect?
The amount of solutes that the kidneys removed or retained to maintain homeostasis
When can glucose occur in urine?
After a sugary meal
When can proteins occur in urine?
After vigorous exercise
What are ketones?
Acids that result from digestion of fats when the body lacks sufficient stores of carbohydrates
What do ketones result from?
Short term fast or a specially designed low carbohydrate diet
What is the most common disorders of the excretory system?
Urinary Tract infections
What is cystitis?
When the bladder has a bacterial or viral infection
What is urethritis?
When the urethra has a bacterial or viral infection
Why are urinary tract infections more common in women?
Because of anatomy. In women the anus and urethra are closer together allowing bacteria to get there easier
What are symptoms of a uti?
Painful burning during urination
A need to urinate frequently
Bloody or brown urine
What is treatment for UTIs?
Antibiotics sometimes if serious surgery is needed
What are kidney stones due to?
Excess calcium in the urine
What contributes to kidney stone formation?
Repeated UTI’s
Insufficient water consumption
Low activity levels
What is renal insufficiency?
A general term used to describe the state in which kidneys cannot maintain homeostasis due to damgae of the nephrons
What are causes of nephron damage?
Kidney infection HBP Diabetes Mellitus Trauma Poisoning Atherosclerosis Blockage of the tubules
What is dialysis?
The diffusion of dissolved substances through a semi permeable membrane
What are the 2 types of renal dialysis?
Hemodialysis and Peritoneal dialysis
What does hemodialysis?
Utilizing an artificial membrane in an external device that is connected to an artery and a vein
What does peritoneal dialysis utilize?
The lining of the intestines
What happens in peritoneal dialysis?
Dialysate is introduced to the abdominal cavity where there is a large surface area and a rich supply of blood. this is where blood is filtered
What 2 sources can transplant organs come from?
Cadavers and live donors
Why can’t anti rejection drugs be used for kidney transplants?
Because they cause kidney damage
What is one of the main reasons that kidneys fail?
High Blood Pressure
Why does high blood pressure cause kidney failure?
HBP causes the heart to pump a greater volume of blood and blood vessels to be damaged. Vessels in the kidneys are very sensitive to changes and can become damaged by HBP and the amount of waste that can be filtered decreases
What can happen as a result of fluid accumulates in the body due to kidney failure?
The extra fluid will increase blood volume and cause blood pressure to rise further
Why is exercise effective for blood pressure?
It stimulates the release of nitric oxide that is produced by the cells on the inside of blood vessels
