9renal physiology week 9 LSB258

Question Answer
what a the remaining roles of the kidney regulation of blood pressure, fluid composition, fluid pH, and hormone secretion for regulating water and salt balance
explain the basic anatomy of the kidney 2 kidneys L & R, surrounded by a connective tissue capsule, the external region is referred to as the cortex the internal region is referred to as the medulla that is segmented into renal pyramids.
explain the gross anatomy of urinary system l and r right kidney with a corresponding ureter, urinary bladder
explain the venous system of the kidney Blood filters in through renal artery and out through renal vein. Interlobar artery is located in between renal pyramids. Arcuate artery and vein is located around the base of renal pyramids. Interlobular artery and vein travels through the cortex
what are the two types of nephrons Cortical nephrons (sit higher in there cortex) Juxtamedullary nephron (sit next to/closer to medulla)
what are the components of the nephron Corpuscle Proximal convoluted tubuleDescending loop of henle Ascending loop of henleDistal convoluted tubuleCollecting ducts, collecting tubules (where concentrated urine is formed)
explain the basic anatomy of the renal corpuscle Afferent arteriole &sphincter (leads into corpuscle)- unfiltered blood enters Glomerulus (capillary bed),covered with podocytesCapsular space (surround glomerulus)Where filtered fluid is collected to further move onto the proximal convoluted tubule Bowman capsule (outer later)Efferent arteriole Filtered blood leaves the renal corpuscle Macula densa cells: monitor concentration of filtrate
what are the 3 components associated with glomerulus filtration Afferent arteriole – carries blood to the glomerulusGlomerulus – a tuft of capillaries that filters an ‘essentially’ protein free plasma into the Bowman’s capsuleBowman’s capsule – collects filtrate
explain the process of filtration in the glomerulus filtration in the capillaries is driven by the hydrostatic pressure of the blood. the endothelium contains fenestrations for small solute molecules to pass through and the basement membrane prevents plasma proteins from being filtered out of the bloodstream. the epithelium made of specialised cells – podocytes wrap around the capillaries leaving fenestration slits that act as a final filtration barrier before fluid enters the capsule space in the bowmans capsule
how much blood from the heart enters the kidneys for filtrations 20-25%
what is the glomerular filtration rate approx. 125ml/min
what controls the glomerular filtration rate The afferent arteriole sphincter which is under sympathetic control
what are the factors that affect glomerular filtration rate the afferent arteriole sphincter, baroreceptors and mean arterial blood pressure, vasoconstriction of the afferent arteriole decreases GFR
what is the hydrostatic pressure of the glomerular 55mm Hg
what is the role of the proximal convoluted tubule where filtered salt and water are reabsorbed. tubular reabsorption.
what is the role of the loop of henle where the counter current multiplier system occurs
what is the role of the distal convoluted tubule to make adjustments of extracellular sodium levels. controls sodium balance through the exchange of sodium and potassium.
what is the role of the collecting ducts to form concentrated urine due to the counter current multiplier system in the loop of henle
explain the capillaries of the nephron the efferent arterioles extended into the peritubular capillary network which leads into specialised vasa recta which is associated with the loop of henle
explain the process of tubular reabsorption sodium is transported into the tubule cell from the filtrate, and co transports by glucose, amino acids, ions, vit. sodium then gets pumped out of the cell in exchange for potassium. the sodium is picked up by the peritublue capillary. where ever sodium goes so does water as well. chlorine is also absorbed along with some urea and fat soluble substances.
what is the most concentrated in salt that urine can be 1200 miliosmals
what is the concentration of salt in blood plasma 300 miliosmals
what is osmolarity the number of particles per litre of solution
what is osmolality the number of particles per kg of solvent (water)
what hormones do the kidneys secrete renin and erythropoietin
what products are reabsorbed by the body 99% water, 99.5% sodium, 100% glucose, amino acids, water soluble vit but only 44% urea
what does passive transport mean the molecules diffuse across the membrane
what does active transport mean pumps are required for a molecule to pass through the membrane
explain the permeability of the defending and ascending loops of henle depending is highly permeable to water but impermeable to sodium. ascending is impermeable to water and there is active transport of sodium, potassium, chloride ions into interstitial space
how is Anti diuretic hormone released osmoreceptors from hypothalamus monitor osmotic pressure. when omostic pressure increases due to the decrease in H2O/dehydration, neurones in hypo. produce ADH and it is released from the poster pituitary.
explain the molecular means of the counter current multiplier system CCMS creates a osmotic gradient through opposite directional flow in the ALH,DLH and the multiplication of osmolarity towards the apex of the medulla. this is cripple for the formation of urine-but not formed here. molecularly NA+Cl and K+ are pumped out of the ALH to causes an osmotic gradient in the ISF; further cause H2O to pump out as well. as H2O is pumped out the filtrate becomes hypertonic (more dilute). filtrate is most concentrated at apex as this is where osmolarity is greatest.
what is the function of Antiduretic hormone to increase reabsorption of h20 in the descending convoluted tubules by opening channels in the cells. this is done by ADH binding to cell receptors to create more aquaporins for the H20, and creating sensation of thirst to replace lost H2O.
What are the effects of the antipyretic hormone Descending convoluted tubules become permeable to H2O, water moves into medullary and urine increases in concentration
how is Antiduretic hormone signalled through either an increase in osmolarity and increase in sodium in the blood stream or a decrease in blood pressure
what receptors control osmolarity and blood pressure osmoreceptors for osmolarity and baroreceptors for BP
Explain the chain of occurrence for ADH osmoreceptors or baroreceptors sense a change in homostasis -> hypothalamus -> posterior pituitary -> ADH -> targets collecting ducts -> water reabsorption increases. negative feedback is from increase in water reasoption to posterior pituitary
what are the juxtaglomerular cells important they contain renin granules for controlling sodium balance
what is the function of aldosterone to open sodium channels in the distal convoluted tubules and collecting ducts. the indirect effect is water reabsorption as sodium and water travel together
explain the sodium balance pathway increase in potassium or sodium in plasma or renin-angiotensin mechanism occurs -> adrenal cortex becomes stimulated -> AC releases aldosterone -> aldosterone targets kidney tubules which creates increase in sodium reabsorption and potassium secretion -> this restores homeostasis of potassium and sodium. negative feed back occurs from restoration to adrenal cortex stimulation
explain the renin-angiotensin system for sodium balance blood vessels in liver have an inactive protein called angiotensinogen circulating -> kidney releases renin to convert into angiotensin 1 -> lungs release ACE to convert to angiotensin 2 -> A2 stimulates adrenal cortex to create aldosterone that acts on kidney to increase sodium and water uptake and also creates arteriole vasoconstriction to increase blood pressure to increase sodium and water uptake in the kidney as well.
what is the function Erythrpoielin and where is it produced EPO increase oxygen carrying ability of erythrocytes due to hypoxia
explain the drainage of the lower urinary tract renal papilla drain into minor and major calyx which drain out through the renal pelvis into the ureter which enters the bladder at openings in the trigone
what s the muscular wall of the baller called detrusor muscle
what keeps urine in the bladder and releases it the voluntary control of the external urethral sphincter which controls micturition reflex
why is the muscular walls important for urine transportation in the ureter important for propelling the urine through peristalis
what is the composition of the musclaris in the ureter circular and longitudinal muscularis
what epithelium is in the ureter transitional epithelium in the mucosa layer
what are the two major roles of the kidney elimination of waste products by filtering the blood and expelling the waste through urine. waste consists of drugs, pesticides, food additives, metabolic waste such as ammonia, potassium, hydrogen ions. and reabsorption of nutrients and water. the body recycles water as a survival mechanism.

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