renal system Flashcards
what are the components of the renal system?
kidneys, ureters, bladder and urethra
what are the different functions of the kidneys?
maintain proper fluid volume, regulate electrolyte levels and acid base balance in the blood.
Kidneys also eliminate waste products liek urea, uric acid, ammonia and creatinine.
Regulate blood pressure through release if renin.
Enable RBC production through release of erythropoietin.
Also convert vitamin D to its active form which is necessary for absorption of calcium.
what are the different functions of the kidneys?
maintain proper fluid volume, regulate electrolyte levels and acid base balance in the blood.
Kidneys also eliminate waste products liek urea, uric acid, ammonia and creatinine.
Regulate blood pressure through release if renin.
Enable RBC production through release of erythropoietin.
Also convert vitamin D to its active form which is necessary for absorption of calcium.
Simple order that filtrate goes through to become urine and be elminated
Blood enters nephron through afferent arteriole and the glomerus will filter the blood at a rate of about 125 ml per minute.
Non-filterable components will exit the glomerulus through the efferent arteriole. This can include proteins and blood cells.
The glomerular filtrate will move on through the tubular structures, including the : proximal convoluted tubule, loop of Henle, Distal convoluted tubule to the collecting ducts.
-As filtrate moves through structures, water, electrolytes and other substances are reabsorbed into circulation or excreted into urine.
what is the functional unit of the kidneys?
Nephron. Responsible for urine formation
describe structure of nephron
Each nephron consists of a glomerulus which is surrounded by a Bowman’s capsule, and tubule structures.
what does RAAS stand for and what is this?
RAAS
Renin-angiotensin-aldosterone system
———
When there is low blood pressure in the body this will cause decreased blood flow to the kidney so decreased renal flow which will cause the kidneys to release renin.
Renin converts angiotensin into angiotensin I, which is then converted into angiotensin II by ACE (angiotensin converting enzyme produced by lungs). This will cause 3 things to happen whihc will INCREASE BLOOD PRESSURE.
1) Vasoconstriction of the afferent arterioles in nephrons which causes increased sodium and water reabsorption.
2) Release of aldosterone from the adrenal cortex which then causes reabsorption of water and sodium at the kidneys.
3) Vasoconstriction of the peripheral blood vessels which will bring up BP of the body.
what is ADH? what is its effect on the kidneys?
So antidiuretic hormone, or ADH, is secreted by the posterior pituitary gland in response
to an increase in the blood osmolarity, meaning the blood is concentrated.
ADH will cause the kidneys to reabsorb water, so not water and sodium but just water, and
that will help to dilute the blood.
It also brings up blood volume as well as blood pressure.
what is the effect of natriuretic hormones on kidneys and blood pressure ?
Then we have natriuretic hormones, which include ANP and BNP, which are released by the cardiac
muscle cells in response to stretch.
So if the heart is being stretched due to excess volume, that will cause the release of BNP and ANP.
In turn, ANP and BNP will stimulate diuresis, so it will cause the kidneys to excrete more
water and more sodium, and this will bring down the body’s blood volume as well as the
blood pressure.
what does it mean when referring to urine’s specific gravity?
electrolytes and urine osmoality
When doing a urinalysis what should the patient’s urine specific gravity be?
1.01-1.025
what does it mean i the urine specific gravity is elevated?
elevated- concentrated
decreased- dilute urine
when doing a urinalysis what should NOT BE present?
glucose, ketones, blood, protein, bilirubin, nitrates and leukocyte esterase.
What are the 2 key blood tests for the renal system?
Creatinine and BUN (blood urea nitrogen)
what are the normal levels of creatinine and what is unhealthy?
normal levels are 0.6-1.2
If we have elevated levels this could indicate kidney dysfunction