Rachel Floyd Flashcards
As a percentage of total body weight, how much do your kidneys weigh?
0.5% of total body weight
What is the average weight of the kidneys combined?
300g
how much cardiac output do the kidneys receive?
~20% of total cardiac output. This is approx 1200ml a minute.
What are the four key functions of the kidneys?
- regulate blood pressure
- stimulate synthesis of red blood cells
- maintain body’s calcium levels
- regulation of blood composition (ion conc, fluid regulation, waste removal, acid/base balance)
What is the role of the renal corpuscle?
Production of filtrate
The proximal convoluted tubule…
reabsorbs water, ions and all organic nutrients
The distal convoluted tubule…
Secretes ions, acids, drugs and toxins. It also has variable reabsorption of water, Na ions, and Ca ions (under hormonal control)
The collecting duct has
variable amounts of reabsorption of water and reabsorption or secretion of sodium, potassium, hydrogen and bicarbonate ions.
The papillary duct
delivers urine to minor calyx
The Nephron loop
further reabsorbs water in the descending limb and both sodium and chloride ions in the ascending limb
How many layers make up the filtration unit of the glomerulus?
3
Why is the glomerulus highly fenestrated?
it allows most molecules to pass but not cells or large proteins
Both cell layers of the glomerulus contain ……………… charged glycoproteins
negatively
………………, foot like processes which integrate forming a filter bed
Podoctytes
In the glomerulus, what is the area of the filtration surface per kidney?
~6m^2
What is the filtration rate?
~125ml/min (180L/day)
How many times does your entire blood volume get filtered each day?
20-25 times
Where does the filtrate filter into?
the Bowmans capsule and then into the Proximal tubule
What are the factors that affect reabsorption?
- rate of flow of the filtrate
- concentration of small moelcules in the fltrate
Where is Anti-diuretic hormone (ADH) secreted?
the pituitary gland
What does ADH control?
the ability of water to pass through the cells in the walls of collecting ducts
What happens if there is no ADH present?
No water can pass through the walls of the ducts so there is more urine
Which receptors in the hypothalamus sense Na concentration?
osmoreceptors
What is the major adaptation to an increased acid load?
increased ammonium secretion
