Please enable JavaScript.

Coggle requires JavaScript to display documents.

Renal system, blood vessels part of the nephron -->, increased activity…

- - - - it remains isotonic even after Na+ and water is absorbed in equal amounts through the proximal tubule
        
        filtrate concentration increases a lot in the descending loop of Henle
        
        filtrate concentration decreases by the end of the ascending loop
        
        the late distal tubule and collecting duct both reabsorb water and Na+ while secreting K+
  - - - simple diffusion
      - Na+/glucose transporter
      - Na+/H+ exchanger
        
        regulated by angiotensin II
  - - - causes lots of glucose to filter through glomerulus
        
        Na+ /glucose co-transporter cannot absorb it all in the filtrate
        
        some glucose is secreted in urine (major symptom)
        
        the co-transporter becomes saturated
        
        Decreases paracellular transport of water and K+
  - - - water diffuses in by osmosis using aquaporins
        
        reabsorbs using paracellular transport and transcellular transport
  - - - solvent drag
        
        K+ is dragged along with the water as it gets reabsorbed
      - simple diffusion
        
        as H2O leaves, K+ is more concentrated in the filtrate
        
        diffuses to interstitial space of kidneys by paracellular route
  - - - K+ use paracellular transport (already there)
        
        after interstitial fluid, they are reabsorbed into circulation by starling forces
        
        capillary hydrostatic force (pc) (13mmHg)
        
        interstitial hydrostatic force (PIF) (6mmHg)
        
        osmotic force due to proteins in plasma (32 mmHg)
        
        interstitial osmotic force (15mmHg)
      - Na+ uses the Na+/K+ pump
      - glucose and amino acids use specific facilitated diffusion transporters
- - - - impermeable to water
      - very permeable to Na+, K+ and Cl-
        
        ion transport is done with the concentration gradient made by the Na+/K+ pump
        
        the Na+/K+ pump drives the Na+, K+ and Cl- pump, moving the ions in at the same time
        
        due to the high increase of K+, K+ leaks back out into the filtrate by simple diffusion
        
        another way Na+ is reabsorbed is the through the Na+/H+ exchanger, reabsorbing Na+ while secreting H+ in the filtrate
        
        25% of the filtered filtrate is reabsorbed here, causing a massive decrease in filtrate concentration
        
        similar to proximal tubule
  - - - during descent the interstitial fluid concentration increases from 300 - 1200 mOsm/kg water to help with reabsorption in the loop of Henle
      - Is permeable to water through osmosis but not ions due to it's impermeable nature
        
        causes the filtrate concentration to increase due to the loss of water. The concentration of the filtrate then matches that of the interstitial space
  - - - 12% of Na+ is reabsorbed
      - in the early segment reabsorption of Na+ is caused by the concentration gradient by the Na+/K+ pump
        
        in the late segment (close to collecting duct), aldosterone increases the activity of the Na+/K+ pump, pumping na+ out
        
        aldosterone increases synthesis of the Na+ channels, diffusing for Na+ in, down the concentration gradient
        
        Na+ is then transported out nephrons by the increased Na+/K+ activity
        
        aldosterone increases K+ secretion into the lumen of the nephron (Na+/K+ pump)
        
        more K+ channels are also getting made on the luminal membrane, secreting K+ in the lumen of the late distal tubule(goes backwards into filtrate)
    - - can vary from 0-15% depending on the person's hydration
      - regulated by the antidiuretic hormone (ADH/vassopressin)
  - - - only reabsorbs 10% of all filtered Na+ and H2O
      - reabsorption always regulated by hormones here
        
        water reabsorption is regulated by ADH
        
        Na+ reabsorption regulated by aldosterone
        
        similar to the distal tubule mechanism, K+ is secreted into the lumen of the collecting duct due to aldosterone
- - - - renal cortex
      - renal medulla
      - calyces
        
        drains into the central renal pelvis
      - renal pelvis
        
        drains into the ureter
      - renal pyramids
        
        contains nephrons
        
        each nephron drains into a collecting duct into a calyx
        
        nephron anatomy
        
        functional unit of the kidneys
        
        over 1 million in each kidney
        
        function
        
        filter blood
        
        reabsorb essential substance
        
        excrete nonessential molecules and waste
        
        parts
        
        glomerular capsule/bowman's capsule
        
        surrounds the glomerulus
        
        1 more item...
        
        tubular portions of the nephrons
        
        proximal convoluted tubule
        
        ascending/descending limb of the loop of Henle
        
        distal convoluted tubule
        
        collecting duct
        
        afferent arteriole
        
        efferent arteriole
        
        peritubular capillary
        
        Vasa recta
        
        blood supply to the nephron
        
        blood from renal artery goes to the interlobular artery
        
        afferent arteriole
        
        1 more item...
        
        processes along the nephron
        
        important definitions
        
        filtration
        
        1 more item...
        
        filtrate
        
        1 more item...
        
        reabsorption
        
        1 more item...
        
        secretion
        
        1 more item...
        
        excretion
        
        2 more items...
      - collecting duct
      - renal arteries
      - renal papillae
      - renal veins
      - ureter
- - - - has it's own negative feedback system
        
        water
        
        controlled variable
        
        effector
        
        amount of water
        
        osmoreceptors
        
        2 more items...
  - - - osmoreceptors signals the posterior pituitary to release ADH
        
        ADH causes water reabsorption in the distal tubule and collecting ducts
        
        reabsorbed water can enter peritubular capillaries due to Starling Forces
    - - volume change detected by volume receptors in the walls of left atrium
        
        more ADH release
        
        more reabsorption in distal tubule and collecting duct
        
        more aquaporins are made
        
        more reabsorption than excretion
  - - - osmoreceptors cause less ADH to be released
        
        less water is reabsorbed in distal tubule and collecting ducts
        
        more water is secreted as urine
    - - volume change detected by volume receptors in the walls of left atrium
        
        cause less ADH release
        
        less reabsorption in distal tubule and collecting duct
        
        less aquaporins are made
        
        more excretion than reabsorption
        
        this can also be caused by alcohol
- - - - regulate electrolyte levels
      - regulate blood pH
      - regulate long-term regulation of arterial pressure
      - regulate water balance
  - - - large arteries branch into many interlobar arteries
        
        interlobar arteries branch into arcuate arteries
        
        blood then flows into the interlobular arteries
        
        blood goes to nephrons
        
        blood drains into the interlobular vein
        
        arcuate vein
        
        1 more item...
- - - - substance diffuse between the tubular cells' tight junction
      - usually non-regulated (no regulation mechanism)
    - - substances go across the tubular cell membrane
        
        goes from lumen into the cell
        
        then from interstitial fluid into the blood
      - can be regulated by hormones but usually non-regulated
    - - uses the Na+/K+ pump to maintain high Na+ outside and high K+ inside
        
        this pump powers other pumps by secondary active transport such as
        
        Na+/glucose co-transporter
        
        when 1 Na+ diffuses in(down its concentration gradient), 1 glucose is carried in along (both goes into the cell)
        
        Na+/H+ exchanger
        
        moves one H+ out of cell for every Na+ that diffuses in
      - secretion
        
        removes unwanted substance from blood into the lumen of the nephron
        
        usually regulated by hormones
        
        can occur without hormones
        
        usually secreted out in the urine
        
        secretes H+ and K+
        
        dependent on the Na+/K+ pump
      - tubular transport mechanism
        
        reabsorption and secretion
        
        Na+ reabsorption
        
        non-regulated mechanisms areas
        
        proximal tubule
        
        site where glucose at glomerulus is reabsorbed
        
        site where amino acids are reabsorbed
        
        ascending loop of Henle
        
        early distal tubule
        
        regulation by the hormones aldosterone and angiotensin II
        
        late distal tubulle
        
        collecting duct
        
        H2O reabsorption
        
        nonregulated mechanisms
        
        proximal tubule
        
        descending loop of Henle
        
        regulated mechanisms with ADH and
        
        late distal tubule
        
        collecting duct
        
        K+ reabsorption
        
        proximal tubule
        
        ascending limb of the loop of Henle
        
        small amounts of K+ secretion occurs in the ascending limb of loop of Henle
        
        more secretion occurs in the distal tubule and collecting duct with aldosterone (regulated here)
        
        K+ secretion is not regulated by hormones at the ascending loop
        
        H+ secretion
        
        regulated mechanism
        
        proximal tubule
        
        ascending limb of the loop of Henle
        
        non-regulated meachanism
        
        proximal tubule
        
        ascending limb of the loop of Henle
        
        can also occur in the late distal tubule and collecting duct
- - - - includes renin-angiotensin system (RAS)
        
        regulates Na+ through reabsorption of Na+ in proximal convoluted tubule
        
        performs chemical reactions converting inactive angiotensinogen to active angiotensin II
        
        angiotensinogen is made by the liver
        
        reacts with renin(enzyme) made in the juxtaglomerular cells found in the walls of afferent and efferent artery, before and after the glomerular capsule
        
        this reaction occurs in low blood pressure or low plasma Na+ levels are low
        
        angiotensinogen is converted to angiotensin I
        
        1 more item...
        
        effects of angiotensin II
        
        strong vasoconstrictor that can increase blood pressure
        
        triggers feelings of thirst
        
        causes you to drink that increases blood volume which in turn increases blood pressure
        
        stimulates release of antidiuretic hormone in the pituitary, increasing water reabsorption by the kidneys
        
        can also cause absorption of water and Na+ from the digestive tract
      - includes the hormone aldosterone
        
        steroid hormone made by adrenal glands (specifically from the adrenal cortex)
        
        secreted during low Na+ levels or high K+ levels
        
        aldosterone returns these ions to normal concentration
        
        cause secretion of K+ and reabsorption of Na+ in the late distal tubule and collecting duct
        
        done by making tubule cells make more Na+ and K+ channels that are inserted into the luminal membrane
        
        aldosterone also increases activity of the Na+/K+ pumps, forming a large Na+ and K+ concentration gradient
        
        secreted in small amount by adrenal corticotropic hormone, in response to angiotensin II
        
        secretion is done by adrenal corticotropic hormone