lecture 28 Flashcards
describe the anatomy of the kidneys
- located posteriorly
- they are retroperitoneal meaning they are behind the peritoneal which is a connective tissue encasement that hold in all your organs in your abdominal cavity
describe the anatomy of the adrenal gland
- sits like a hat over the kidneys
anatomy and function of ureter
- 2 tubes that lead from kidney to bladder
- drain urine from kidney where it is produced to bladder where urine is stored and then excreted from bladder
describe the anatomy of the urethra
the tube connecting the urinary bladder to external environment
what is the breakdown product of hemoglobin
uribilinogen
renin
- an enzyme that is important for regulating blood pressure
- produced by the kidneys
General functions of the kidney
- kidneys essentially dictate how much water leaves in urine and how much water stays, and by regulating water loos and water keep we regulate extracellular volume fluid and therefore also blood volume. And if we’re regulating plasma volume we’re also regulating blood pressure
- Regulation of osmolarity
- Maintenance of ion balance (Na+ and K+)
- Homeostatic regulation of pH because kidneys can secrete/offload H+ and HCO3- as needed
- Excretion of wastes (creatinine, urea, hormones, uribilinogen)
- Production of hormones (erythropoietin and renin)
renal pelvis
- all nephrons lead here
- a hollow space that fills with urine and drained into bladder via the ureter
nephrons
the functional unit of the kidney
approximately how many nephrons are there per kidney?
1 million
what does the cortex contain
- bowman’s capsule
- proximal tubule
- distal tubule
what does the medulla contain
- loop of henle
- collecting duct
Why is the anatomy of the loop of henle important
because it is a hair pin like structure it creates a motor that allows us to excrete a very dilute urine or a very concentrated urine depending on bodies needs
what is the role of the loop of henle
regulating urine concentrations
renal artery
takes blood to your kidneys and filters it
renal vein
is blood coming out of kidneys after being filtered and being put back into circulation
peritubular capillaries
- deliver nutrients to the nephron (blood)
- serves as a re-entry point for reabsorbed substances to get back into circulation
which is the correct order of structures a molecule of glucose might pass through
- glomerulus
- bowman’s space
- proximal tubule
- loop of henle
- distal tubule
- collecting duct
- renal pelvis
- ureter
- bladder
Give the % of total plasma volume that filters into the tubule
- 100% plasma volume entering via afferent arterioles
- 80% of plasma will re-enter circulation via efferent arteriole and 20% of volume filters
- 99% of that 20% will be reabsorbed
- Leaving 1% to be excreted
Podocyte
- single cell epithelium
- have foot processes that create windows called fenestrations
- out of capillary through fenestrations and now we’re in bowman’s space
Functional anatomy of the nephron
Bowman’s capsule :
- filtration occurs because glomerulus is leaky because there is very few tight junctions, stuff being filtered is glucose, Na+, water, K+
- Stuff will leak into bowman’s space because glomerulus is leaky
- Filter 180 L/ day of blood a day
proximal tubule:
- glucose and Na+ are reabsorbed
- H+ and K+ are secreted
Loop of Henle
- Reabsorption
Distal tubule/ collecting duct
- somewhere here vasopressin causes insertion of water channels for water reabsorption as needed
- How much water we let go (filter) vs. how much we reabsorb will determine concentration of urine but more importantly determines blood volume and blood pressure
- We excrete 1.5 L/ day in form of urine (urea, k+, h+, h2o), this means vast majority of what our kidneys filter is reabsorb
Water will move towards
Highest concentration of solutes
What pressure is GFR influenced by?
Hydrostatic pressure (Ph): is the blood pressure of blood that enters the glomerulus and it’s gonna cause a push therefore being for filtration
Colloid osmotic pressure gradient (π) water will move from a lower concentration of solutes to a higher concentration of solutes, so if protein is getting left behind and protein acts as a solute that will oppose filtration because it’s gonna tend to pull fluid or plasma back.
Fluid pressure within bowman’s capsule (Pfluid): as fluid collects in bowman’s there will be a hydrostatic pressure that pushes back
Give values to pressures GFR
Hydrostatic pressure (Ph) = 55 mm Hg
Colloid osmotic pressure gradient (π) = 30 mm Hg
Fluid pressure in bowman’s capsule (Pfluid) = 15 mm Hg
Ph - π - Pfluid = 10 mm Hg (net filtration pressure)
