CH 53 Kidney and Urinary function Flashcards
- Urine formation
- Excretion of waste products
- Regulation of electrolytes
- Regulation of acid-base balance
- Control of water balance
- Control of blood pressure
- Renal clearance
- REgulation of RBC production
- Synthesis of Vit. D to active form
- Secretion of prostaglandins
- Regulates calcium and phosphorus balance
functions of kidney
Amount of cardiac output received by the kidneys
20-25%
the tuft of capillaries forming the part of the nephron through which filtration occurs.
glomerulus
Blood LEAVES the glomerulus through through this arteriole and flows back to the inferior vena cava.
efferent arteriole
These are located in the renal parenchyma and are responsible for urine formation. If there are less than 20% of these are functioning then renal replacement therapy should be considered.
nephrons
The usual capacity of the adult bladder, but it can distend.
400-500mL
These substances are normally filtered by the glomerulus, reabsorbed by the tubules, and excreted in the urine.
Sodium, chloride, bicarbonate, potassium, urea, creatnine, and uric acid
these substances are reabsorbed in the blood so that neither are excreted in the urine.
amino acids and glucose
Normal blood flow through the kidneys per minute
1,000-1,300 mL/min
Blood goes INTO the glomerulus through this arteriole.
afferent
A horomone secreted by the posterior pituitary gland in response to changes of the osmolarity of the blood. If there is decreased water intake blood osmolality tends to increase causing a release of ADH
ADH
refers to the ratio of solute to water.
osmolarity
The degree of dilation or concentration of the urine is measure in terms of this.
osmolality
A hormone that is synthesized and released by the adrenal cortex. It regulates the amount of sodium volume excreted..
Increased levels means less sodium excreted.
-It is largely controlled by angiotensin II
aldosterone
The two major functions performed by the kidneys to assist in acid-base balance.
- To reabsorb and return to the body’s circulation any bicarb. from the urinary filtrate.
- To excrete acid in the urine
Two important buffers
Phosphate ions and ammonia(NH3)
specialized vessels of the kidneys that monitor BP.
vasa recta
the most powerful vasoconstrictor known which causes BP to increase
angiotensin II
refers to the ability of the kidneys to clear solutes from the plasma.
Renal clearance
This is done as the primary test of renal clearance used to evaluate how well the kidney performs excretory function.
24 hour urine collection
an endogenous waste product of skeletal muscle that is filtered at the glomerulus, passed through the tubules with minimal change and excreted in the urine.
Creatnine
the amount of plasma filtered through the glomeruli per unit of time.
GFR
This is released by the kidneys when they detect a decrease in oxygen in renal blood flow. It stimulates RBC production
erythropoietin
The kidneys are responsible for the final conversion of inactive vitamin D to its active form. Vit. D is necessary for maintaining calcium balance in the body
Vitamin D
These are prostaglandins produced by the kidneys. They have a vasodilatory effect and are important in maintaining renal blood flow.
Prostaglandin E and prostacyclin
This is the major waste product of the kidneys. It must be excreted through the urine otherwise it will accumulate in the tissues.
Urea
The reservoir for urine. Filling and emptying are controlled by SNS and PNS and the detrusor muscle.
the bladder
an expression of the degree of concentration of the urine that measures the density of a solution compared to the density of water which is 1.000. It is altered by the presence of blood, protein, and casts in the urine.
specific gravity
- When fluid intake decrease specific gravity increases and vice versa.
- In patients with kidney disease the patient’s urine is said to have a fixed specific gravity( It does not fluctuate with fluid intake)
specific gravity
This is the most accurate measurement of the kidney’s ability to dilute and concentrate urine. Normal serum osmolality is 200-300 mOsm/kg and normal URINE osmolality is 200-800 mOSm/kg for a 24 hour sample 300-900 mOsm/kg
Osmolality
renal concentration test, creatinine clearance, and serum creatinine and BUN
Renal function tests
what stimulates Renin?
low BP
remember renin raises
stored in the liver
angiotensogen
holds on to sodium and water gets rid of potassium. This is blocked in ACE inhibitors thats why they cause hyperkalemia
aldosterone
