The kidney Flashcards
What oral disease has a link to kidney disease.
Periodontitis.
Describe the path of urine in the body.
Kidneys produce urine, travels to the ureters, stored in the bladder and is passed via the urethra.
Where does the kidney sit in the abdomen? (peritoneum)
Retroperitoneal.
What is the kidney encased in?
Renal fat pad.
Name the macroscopic features of the kidney.
Capsule, cortex, medulla and the pelvis.
What macroscopic feature contains Nephrons? What are nephrons?
Nephrons (kidney tubules) are the basic functional units.
Some structures are found in the Cortex (convoluted tubules and the renal corpuscle) some are found in the medulla (loop of Henle and collecting ducts).
What is the purpose of the kidney medulla?
Concentrate urine.
Water reabsorption.
What vessel does the renal artery receive blood from?
Abdominal aorta.
What vessel does the renal vein deliver blood to?
Vena cava.
What is the function of the nephron?
Filter blood plasma and exert waste products.
What is unique about the blood vessels of the kidney?
There are capillary beds between arterioles.
What is the glomerulus?
Capillary mesh surrounded by the bowman’s capsule.
What is the function of the juxtamedullary nephron?
Reaches deep into the kidney’s medulla and concentrates urine.
What is the function of the proximal convoluted tubule?
Reabsorbs nutrients water and waste.
What is the function of the Loop of Henle?
resorbs water and concentrates urine. (more water resorbed = more conc urine.)
What is the function of the distal convoluted tubule?
Fine tuning of the filtrate. Additional water and electrolytes absorbed.
What is unique about the inner lining of the bowman’s capsule?
Specialised epithelium lined with podocytes.
feet processes wrap around the glomerulus capillaries creating the filtration barrier..
Where is the primary site of filtration?
Renal corpuscle.
What forms the renal corpuscle?
The glomerulus and the bowman’s capsule.
What is the filtration barrier permeable to?
Water, (small molecules) glucose, amino acids, urea, creatinine, phosphate, chloride, sodium, potassium, bicarbonate.
What does the filtration barrier prevent entry of?
Negatively charged molecules and large proteins i.e. haemoglobin.
What is the primary driving force of glomerular filtration?
The glomerular hydrostatic pressure gradient.
How does the glomerular hydrostatic pressure gradient work?
The afferent arteriole has a wider diameter than the efferent arteriole therefore blood arrives quicker than it can leave, forcing small molecules through the filtration barrier.
What pressures are responsible for counteracting the glomerular filtration rate?
Bowman’s capsule hydrostatic pressure.
Glomerular osmotic pressure.
(Proteins trapped in the glomerulus drive water back in)
Why does kidney disease go undetected for so long?
Kidney has an excess capacity.
At what stage is kidney disease usually detected at?
Stage 3. Significant damage can occur before symptoms start to show.
What percentage of sodium is reabsorbed into the blood?
98%
65% PCT
25% ascending LofH
8% in DCT
In the prox CT how does water move?
Via aquaporins.
Water moves due to the osmotic forces generated by Na and Cl movements.
Water follows Na.
Passive movement.
In the proximal CT how do glucose and amino acids move?
Via Na co-transporters.
In the proximal CT, what percentage of movement is via passive diffusion?
50%
Na/K pumps on the basolateral membrane of kidney tubules are reabsorption for what percentage of Na movement?
65%
Describe tubule fluid flow in the loop of Henle.
Opposite direction.
Describe the limbs of the loop of Henle.
Descending limb is thin.
Ascending limb is thin AND thick.
In terms of water; the thin limb is..?
Permeable to water. (mostly impermeable to ions)
In terms of water; the thick limb is..?
impermeable to water.
In the thick limb of the ascending loop of henle, what creates the osmotic gradient?
Active movement of Na and Cl
What is the osmotic gradient in the medulla?
High : hypertonic.
In the loop of Henle, where is the tubule fluid most concentrated?
At the loop.
What is the osmotic pressure of the fluid entering the Distal CT?
hypotonic.
What is reabsorption controlled by in the distal CT?
Hormones.
ADH
Aldosterone
ANH
What is the function of ADH?
Increases water reabsorption.
Main control of water balance.
Assisted by aquaporins.
What structures of the nephron does ADH act on?
Increases the water permeability of The DCT and collecting tubules. (permeability also increased by aquaporin channels)
What effect does ADH have on urine?
Concentrates urine.
What is the function of Aldosterone?
Increases Na reabsorption and indirectly regulates water reabsorption
What structures of the nephron does Aldosterone act on?
The DCT and collecting tubules.
What effect does aldosterone have on urine?
Concentrates urine.
What is the function of ANH?
Increases excretion of Na by working against ADH and aldosterone.
What effect does ANH have on urine?
Dilutes urine.
Describe the events that would occur if there was an excess of tubular fluid.
Elevated blood volume.
Elevated blood pressure.
Large volume of dilute urine.
Reduces blood pressure.
Describe the events that would occur if there was an reduction in tubular fluid.
Reduced blood volume
Reduced blood pressure.
Small volume of concentrated urine.
Elevated blood pressure.
What are the functions of the juxta-glomerular cells?
Modified smooth muscle cells.
Surrounds the afferent arteriole and adjusts the diameter.
Regulates sodium concentration.
Name the 2 main cell types in the kidney tubules.
Macula densa cells.
Juxtaglomerular cells.
What do the macula densa cells do?
Specialised epithelium that measures the concentration of sodium as is passes.
What is the native conformation of juxtaglomerular cells?
Dilated
How do the macula densa and the juxtaglomerular cells work in response to increased blood pressure?
Increase in BP
Increase in hydrostatic pressure and the filtration rate.
Increased concentration of sodium.
Macula densa sense the change in sodium and release adenosine.
Adenosine is recognised by the juxta cells and they constrict.
Constriction reduces pressure and rate.
Sodium conc returns to normal.
What is the purpose of the renin-angiotensinogen system?
Restores blood pressure and volume via the action of ADH and aldosterone.
Describe how the angiotensinogen system works.
Angiotensinogen released into the circulation in response to low blood pressure/volume.
Renin converts angiotensinogen into angiotensin 1.
Angiotensin 1 is converted to 2 by renin.
Angiotensin 2 is a vasoconstrictor, rapidly increases blood pressure.
What are the effects of Chronic Kidney disease.
Decreases rate and function.
What are some of etc symptoms of CKD?
Nausea.
Oedema.
Anaemia.
What drugs can cause kidney disease?
Ibuprofen.
Non steroidal anti-inflammatory drugs.
What is a cause and a symptom of CDK?
hypertension. (High BP)
How can hypertension be regulated?
ACE: Blocks angiotensin 1 being converted to 2 (vasoconstriction doesn’t occur and blood pressure not increased)
Beta blockers: Block sympathetic nerve stimulation.
What is the action of Furosemide?
Blocks the Na/K pump in the loop of Henle.
Prevents Na and water resorption.
In terms of pharmokinetics; What dosages are those with CKD prescribed?
Lower dosages- harder to remove drugs from their systems.
What manages kidney failure?
Dialysis
What is dialysis?
Artificial removal of water and waste/toxins from the blood.
Name the 2 types of dialysis.
Haemodialysis.
Peritoneal.
What is haemodialysis?
Blood filtered through a machine
What is peritoneal dialysis?
Fluid inserted into the peritoneum which forms a semi-permeable membrane.
Dialysis occurs through the membrane.
What are the pros of the peritoneal dialysis?
Is mobile.
Can be carried out at home/sleeping etc.
What is movement in the proximal convoluted tubule driven by?
Sodium. Everything follows sodium.
What factors determine what enters the nephron?
Size and charge.
What process occurs in the loop of henle?
Countercurrent multiplication: in the descending limb water is reabsorbed passively as a result of ions being active reabsorbed in the thick ascending limb. .
What is the function of the juxta-glomerular apparatus?
Controls blood pressure.
List functions of the kidneys.
Water balance.
Ionic balance.
Regulating blood pressure.
Regulating calcium.
What is the roles of aldosterone in the kidney?
Steroid hormone that promotes Na resorption in exchange for K.
In the DCT so Allows fine tuning of the filtrate.
Describe water resorption in the kidney. (3)
Follows Na resorption.
Water is reabsorbed by the osmotic forces generated by the movement of Na and Cl.
Passive movement. Not regulated.
