Urinary System Flashcards
(43 cards)
what are the urinary organs?
kidneys, ureters, bladder and urethra
write a short note on the kidneys
location: either side of the vertebral column under the diaphragm.
structure: bean shaped, red/brown, fist size. covered in connective and adipose tissue
describe the structure and location of the ureters
Extend from kidney to bladder. Small muscular tubes which are 25cm in length, 5-7mm diameter. Consist of smooth muscle. Peristalsis occurs here. Lined by transitional epithelium, underlying connective tissue, muscularis and adventia (fibrous layer with blood vessels)
what is the Hilum
where the renal artery enters the kidney, and the renal vein and ureters exit the kidney
write a note on the bladder
Balloon shaped. Thin and transparent. Holds 400-600mls urine. Has 2 sphincters where urethra exits.
write a sentence on the urethra
extends from bladder to outside. 4 cm in length in women, 20cm in men
what are the 4 functions of the kidneys
excretion of metabolic waste. maintenance of salt/water balance. pH maintenance. hormone secretion
what wastes are excreted by kidneys
Nitrogenous waste:
1. urea ( formed in liver - ammonia + CO2)
2. Creatinine: produced by creatine phosphate in muscles
3. Uric acid: nucleotide metabolism waste (purines). Uric acid dissolves in blood and is filtered by kidneys
explain the water/salt balance function of kidneys
Salt balance influences blood volume as water follows salt. So, increased salt in blood = increased blood volume. A higher blood volume then = hypertension. Kidneys regulate the amount of ions in blood
How do the kidneys maintain pH
Blood should be pH of 7.4. Kidneys excrete H+ and reabsorb HCO3- to maintain pH
What hormones are secreted by the kidneys?
Renin which stimulates aldosterone secretion which reabsorbs sodium ions.
Erythropoietin: stimulates RBC production.
What relationship do the kidneys have with vitamin D
They activate vitamin D. This vitamin activates calcitrol which promotes Ca2+ absorption in the digestive tract.
What are the three regions of the kidney?
cortex, medulla and pelvis
what is a nephron?
an independent urine forming unit
function of renal artery?
oxygenated blood to kidneys
function of afferent and efferent arterioles?
afferent: blood to glomerulus which supplies the nephrons.
Efferent: blood away from glomerulus
function of peritubular capillaries?
supplied by efferent arteriole. travel along nephrons and allow reabsorption and secretion between blood and inner lumen.
They surround the proximal and distal tubules and the loop of Henle (called vasa recta here)
function of renal veins?
carry filtered blood away
what are the functions of the nephrons
- initial filtration of blood
- selective re-absorption of filtered substances back into blood
- secretion of unwanted substances
the nephron has two components, what are they?
tubular and vascular
what are the parts of the tubular component
Bowmans capsule, Proximal convoluted tubule (PCT), Loop of Henle, Distal convoluted tubule (DCT), collecting duct
write a note on Glomerular (Bowmans) capsule
located at the beginning of tubular component of nephron. Performs first step of blood filtration. Glomerulus is enclosed in a sac.
Outer layer: squamous epithelium
Inner layer: made of podocytes (long cytoplasmic extensions)
Allow the passage of materials but not blood (aka glomerular filtration)
write a note on the Proximal Convoluted Tubule (PCT)
This is beside glomerulus. Lined with cuboidal epithelium. Has microbilli for increased surface area for filtrate absorption. Cells of PCT have many mitochondria for active transport energy
write a note on the function and structure of the Loop of Henle
This can be divided into descending and ascending limbs.
Epithelium lining has special filtration abilities that can re-absorb water and concentrate the filtrate.