W11 Flashcards
List the major organs of the urinary system
Kidneys (2): process blood and form urine.
Ureters (2): Tube running from each kidney to urinary bladder.
Urinary bladder: reservoir for urine before leaves body - expels urine.
State and describe 5 functions of the kidneys other than urine formation
Blood plasma filtration - the kindeyys act as a blood filter to identify and excrete toxic waste products.
- Regulation of blood volume - by conserving H2o or elimination H2o.
- Regulation of body fluid osmolarity: regulate salt in plasma (Na+, K+, Ca2+, Cl-)
- Regulation of blood pressure: kidney secrete renin which ↑ bp by activating renin-angiotension-aldosterone pathway.
- Produces erythropoietin: production of RBC
- Production of calcitriol (vit D): helps in absorption of calcium from GIT, regulating calcium homeostasis.
- Regulate blood pH ; kidneys excrete H+, maintains balance of body fluids
- Gluconeogenesis: kidneys can use amino acid glutamine to synthesis new glucose,
Name the major nitrogenous wastes and state their sources
- Urea - Protein catabolisim → amino acids → -NH2 removed and converted by the liver → urea. Urea is most abundant nitrogenous waste.
- Uric acid: nucleic acid catabolisim
- Creatinine: creatine phosphate catabolisim
Describe the location and gross anatomy of the kidneys
Kidneys lie against posterior abdominal wall at level of T12 to L3. Retroperitoneal (located behind the peritonum) along with ureters, urinary bladder, renal artery and vein w adrenal glands. Right kidney is slight lower due to the large lobe of right liver.
Size of fist, roughly oval. Has a slit for nerves, blood vessels, lympathics.
Internal structure: Renal cortex: outter tissue Renal medulla: inner tissue Renal colums: between medullary pyramind (comlums) Calyx: urine collecting region
Trace the flow of blood through the kidneys & identify the vessels
Renal artery: brings blood into each kidney
Interlobular arteries: extending towards the cortex
Describe the nephron and its 2 parts (renal corpuscle and renal tubule)
The nephron is the functional unit of the kidney, responsible for urine formation. Made up of two regions (renal corpuscle and tubule) connects to a shared collecting duct.
Afferent arterioles enters glomercular capillary network.
Efferent arteriole leaves glomerulus and extends to the peritubular blood supply. Then Vasa Recta capillary network surrounding Henleys loops required for urine formation.
The renal corpuscle:
Rental Tube: PCT is the first part of the renal tubule; segment nearest to the Bowmans capsule
Describe the filtration membrane and the process by which the kidney filters the blood plasma
Filtration is the first step in blood processing. Occurs in the renal corpuscles as a result of a pressure gradient. Glomerular filtration rate (GFR) determined mainly by glomerular hydrostatic pressure and therefore directly related ti systemic bp.
Filtration membrane: three barriers through which fluids pass.
1. Fenesrated endothelium of glomerular capillaries: are highly permeable, excludes RBC from filmtration.
2. Basement membrane: small protein bound solutes don’t pass - charge.
3, Filtration slits of podocyte:
Explain the forces/factors that promote and oppose filtration
MORE INFO Filtration pressure: GFR
Promote: Rental artery ↑ volume of blood
Describe how renal autoregulation controls glomerular filtration rate
MORE INFO Myogenic mechansim: based on the tendency of smooth muscle
Tubuloglomerular mechanism: involved Juxtaglomerular apparatus: volume and concerntration of filtrate analysed by Marcula densa cells at the distal tubule → signsals to Juxtaglomerular cells to regulate blood flow.
Describe how the nervous system controls glomerular filtration rate
SNS control of GFR strenous exercise/constriction can stimulate afferent arterioles to constrict. This leads to ↓ GFR and urine production redirecting blood flow to heart, brain
Describe tubular reabsorption and how it takes place
Reclaiming water and solutes from the filtrate and returning them to the blood.
Tubular reabsorption: Na+ transported into blood. Glucose: passively transported. Chloride
Mechanisims
Describe tubular secretion and state solutes that are excreted
The movement of substance out of the blood into tubular fluid. Secrete potassium and amonium. Waste removal: waste products. Acid-base balance.
Describe how the nephron regulates water conservation
The Nephron Loop (Loop of Henley). It generates salinity gradient, allows the collecting duct to concerntrate urine.
Discuss the roles of aldosterone, atrial natriuretic hormone (ANH) and parathyroid hormone (PTH) on kidney function
Aldosterone: secreted by adrenal cortex ↑ distal tubule absorption of sodium, ↑ Na+ in blood. ↑ Na+ reasborption and collecting duct in Na+ channels
ANP:
PTH: Secreted by parathyroid for in response to calcium deficiency. ↑ phosphate content and ↓ calcium in urine
Explain how the collecting duct and antidiuretic hormone (ADH) regulate the volume and concentration of urine
MORE INFO Dependant on hydration. Drinking large amounts of water will produce large volume of hypostatic urine