Renal System Flashcards
explain how oral health impacts general health
there is association between oral health and cardiovascular health, arthritis, respiratory disease, metabolic diseases and kidney diseases
pathological inflammatory pathways underlie a wide raneg of chronic health problems
describe the gross, macroscopic and microscopic structure of the kidney
gross
- two kidneys produce urine
- ureters convery urine
- bladder stores urine
- urethra voids urine
- highly vascular, renal artery delivers blood from abdominal aorta
- 1.2 litres are processed per minute (1/5 CO)
macroscopic
- three distinct parts
- cortex, contains 85% of all kidney tubules
- medulla, the site where urine is concentrated, prevents excessive water loss
- pelvis, collection area for urine which is funnelled into the ureter
microscopic
- nephron is basic functional unit
- filters blood plasma and excretes waste products of metabolism in urine
- there are cortical nephrons and juxtamedullary nephrons
- composed of a renal corpuscle and a renal tubule
list the functions of the kidney
- excretory organs that process blood and rid the body of the waste products of metabolism via urine
- maintain internal homeostasis of fluid
describe the structure and function of the renal corpuscle in relation to glomerular filtration
renal corpuscle is composed of the glomerulus and bowmans space
glomerulus
- fine capillary network
- single layer of endothelial cells resting on a basement membrane
- fenestrated
- enables rapid filtration of blood plasma
- surrounded by bowmans capsule
bowmans capsule
- cuplike structure surrounding the glomerulus
- parietal outer layer
- inner visceral layer composed of podocytes
- pedicels of podocytes wrap around glomerular capillaries
filtration barrier
- formed from glomerular endothelium, basement membrane, pedicels
- freely permeable to water and small molecules but not large proteins or cells
- size and charge of filtration slits provide the barrier to determine which molecules are filtered
define glomerular filtrate rate and implications for kidney health
glomerular filtration is the first step in blood processing. has three stages
- unfiltered blood arrives at the glomerulus via the afferent arteriole
- blood components filtered through the filtration barrier
- filtered blood then exist the glomerulus via the efferent arteriole
hydrostatic pressure gradient faciliates this filtration.
glomerular filtration rate is the rate at which blood is filtered through the glomerulus into the bowman’s capsule, and is driven by glomerular hydrostatic pressure.
bowmans capsule hydrostatic pressure counteracts this, as well as glomerular osmotic pressure.
kidney damage reduces the GFR, and a reduced GFR means there is inefficient blood clearance and waste removal. waste products will accumulate in the blood and serum creatinine is measured to determine the GFR
99% of filtrate is reabsorbed.
180 litres of blood are filtered each day.
describe the relationship between structure and function for each section of the renal tubule
PCT
- reabsorption and secretion
- NaK pump on basolateral membrane uses 1 ATP to move out 3 Na and 2 K in.
- sodium moves against its concentration gradient.
- water follows sodium, glucose and amino acids are cotransported, and chloride and negative ions follow sodium too
- absorbs 2/3 filtrate (65% sodium reabsorption, 65% water, 65% negative ions, 100% nutrients)
loop of henle
- counter current multiplication in juxtamedullay nephrons only
- receives 60 litres
- thin descending has aquaporins, water flows out of filtrate into the medulla
- thin ascending limb has no aquaporins or sodium pumps
- thick ascending limb is the site of active sodium reabsorption via NKCC2 on the apical membrane
DCT
- reabsorption and secretion
- is acted on by hormones
collecting duct
- urine collection
describe the process by which sodium reabsorption facilitates reabsorption of nutrients and water in the proximal convoluted tubule
sodium moves against its concentration gradient in the NaK pump and then everything else just follows it
describe the process by which reabsorption of sodium facilitates water reabsorption in the loop of henle
water flows out of the tubule by osmosis into salty medulla.
reabsorbed water enters vasa recta
identify the hormones that act on the distal convoluted tubule and describe how they function to fine tune the filtrate
ADH - inserts aquaporins to increase water reabsorption
aldosterone - inserts channels to increase sodium reabsorption
ANH - promotes secretion of sodium and water by removal of aquaporins and channels
describe the processes by which the kidneys regulate blood pressure
identify components of the juxtaglomerular apparatus and describe their role in regulating GFR and blood pressure
kidneys measure GFR as a proxy for systemic blood pressure
describe the RAAS and its role in regulating fluid volume
describe the association between chronic kidney disease and heart disease
describe the mechanism of action of furosemide and how this drug relieves the symptoms of hypertension
describe the macroscopic structure of the kidneys
liver influences the position of the right kidney so it usually lower than the left
kidneys are surrounded by the ribs, abdominal wall muscles and a renal fat pad that surrounds each one.
renal vessels
- left renal vein is longer and must pass anterior to the aorta to drain into IVC
- left receives blood from the left gonodal vein
- IVC is more right and aorta is more left
longitudinal sectioning of the kidney
- outer kidney is the cortex, contains renal columns
- renal medulla is organised into pyramids
- apex of each medulla has a papilla, where waste fluid drains into minor calyces which drain into the renal pelvis.
- pelvis narrows to form the ureter
ureters
- retroperitoneal, lie against posterior structures of the abdomen
- blockages can occur where they pass anterior to the common iliac vessels to pass the pelvs inlet and enter the pelvis
location of the bladder
- posterior to the pubic symphysis
- entry of the ureters is at the posterior inferior wall of the bladder.
- urethra is at the inferior apex of the triangle
- wall is mostly muscle, retaining shape if distended and prevents rupturing.
female urethra
- anterior orifice of the pelvic floor, posterior to clitoris
- single distal connection from the urinary bladder
male urethra
- emerges from floor of bladder into prostate
- converged with vas deferens (ejactulatory ducts)
- supported by connective tissue and muscle when it is the membranous urthethra
- pendulous urethra is the urethra in the penis
- has three parts: internal sphincter to prevent ejaculate entering the bladder, external sphincter around membranous urtherthra to prevent urine leakage and provide voluntary control of urination.
- function inhibited during ejaculation
