Urinary System 1 Flashcards
What are parts of the urinary system + what they do?
Kidneys (pressure filter producing urine from blood)
Renal Pelvis (into which urine is drained)
Ureters (carry urine to urinary bladder)
Bladder (stores urine)
Urethra (tube between bladder and external environment)
What are the functions of the kidneys? (7)
1.Regulate blood volume and electrolytes
2.Removal of urea from the bloodstream
3.Conserving nutrients
4.Regulate acid-base balance
5.Regulate blood pressure
6.Calcium homeostasis
7.Production of erythropoeitin and renin
What are some kidney disorders/ damage conditions?
*Acute Kidney Injury
*Chronic kidney disease
*Polycystic Kidneys
*Kidney infection
*Kidney stones
What are some regions that excrete metabolic waste?
*skin
*lungs
*liver
*kidneys
What are the three major renal processes?
1.Filtration
2.Tubular reabsorption: passive and active process returning material to the blood from the filtrate
3.Tubular secretion: Removing material from the blood into the filtrate
How much do kidneys quantify for? + cardiac output?
Kidneys are < 1% of body weight
Yet receive about 25% of Cardiac Output
¼ of all ‘work’ performed by heart is to perfuse kidneys
What is the kidneys functional unit?
Functional unit is the nephron
Approx 2.5 million
Each approx 5 cm in length about 50 µm in diameter
Approx 125 km of tubing (not including blood vessels)
What does the kidney process?+how much
Processes 180 L plasma/day
Only about 1.5 drops per nephron
Of which ~ 1% ends up as urine
About 600g of sodium reabsorbed per day
What substances are filtered and reabsorbed in the kidney?
- water glomerular filtrate = 180-200L/day
- sodium chloride
- glucose
reabsorbed as long as plasma glucose < 200mg/100ml
*hydrogen ions - urea - H2N-CO-NH2 2/3 filtered is passed out
*toxic substances
body metabolites drugs + drug metabolites
some of these may be actively secreted
What is urine composed of?
Relatively high concentrations of:
Urea
Uric acid
Creatinine
K+
Other substances that are toxic
Rest reabsorbed
How is the nephron distributed?
The functional unit of the kidney (renal corpuscle and tubule)
Each nephron has two components
Vascular (blood)
Tubular (filtered fluid)
Some of the nephron is in renal cortex
outer region
granular
Some of the nephron is in renal medulla
inner region,
made up of triangles (renal pyramids)
What is the path of urine?
glomerulus → Bowman’s capsule → proximal CT → loop of Henle → distal CT → collecting tubule → collecting ducts → calyces → renal pelvis → ureter → urinary bladder → urethra
