Test 5 Study Guide Part 5 Flashcards
Incontinence:
- Paraplegics:
- Treatment:
Inability to control bladder and poop production
- Paraplegics:
Cannot control external sphincter, incontinent
- Treatment:
Urinary catheter (Foley catheter)
Urination:
- Alternative Name:
- Alternative Name:
Micturition
The guarding reflex:
Controlled by spinal cord
Parasympathetic nerves of the detrusor inhibited.
Somatic nerves to external sphincter stimulated
The voiding reflex:
Stretch receptors stimulated in bladder ->
pons micturition center is stimulated ->
Parasympathetic nerves to detrusor activated, internal sphincter relaxed ->
feels urge to pee
Somatic neurons which innervate the external sphincter
Pudendal nerve:
Higher brain regions (cerebral cortex) affect on urination:
Inhibits the micturition center of the pons.
Decision to urinate -> relax inhibition of pons (activate micturition center) -> sensory stretch information from bladder can now activate micturition center -> pudendal nerve inhibited -> parasympathetic nerve to detrusor is activated -> voiding of urine
Collection bags for urinary catheters should be higher or lower than the patient?
Lower, so urine doesn’t flow backwards
Afferent means:
Towards the center of activity
How does blood reach the nephron?
Renal Artery -> afferent arterioles
Efferent Arteriole:
Drains the glomerular capillaries, brings to the peritubular capillaries
Is blood flow in the kidneys a portal?
No, because an arterial not a venule drains one capillary to the next
Blood flow to and through the kidney’s
Renal artery -> interlobar arteries (pass between pyramids) -> arcuate arteries (pass over pyramids) -> interlobular arteries -> afferent arterioles -> glomerulus -> efferent arterioles -> peritubular capillaries -> renal venules -> interlobular veins -> arcuate venules -> interlobar venules -> renal vein
peritubular capillaries:
- Function:
- Function:
Allows blood TAKE back nutrients from the filtrate in tubules or ADD
Tubular network of the nephron, all names:
Glomerular capsule -> proximal convoluted tubule -> descending limb of loop of henle -> ascending limb of loop of henle -> distal convoluted tubule -> collecting duct
Renal corpuscle:
Glomerulus
Glomerular (bowman’s) capsule
Glomerular capsule/bowman’s capsule:
channels it into the proximal tubule, helps to filter.
Two layers, the space between these layers is continuous with the lumen of the proximal convoluted tubules
Proximal tubules epithelial cells:
- Distinctive features:
- Function:
- Distinctive features: Brush border lots of mitochondria - Function: Active transport of molecules from the lumen, to the peritubular capillary network
Two types of nephrons and positions:
Juxtamedullary nephrons, lower 1/3 of cortex, descend into medulla:
Cortical nephrons, upper two thirds:
Endothelial cells glomerular capillaries fenestration:
large pores, prevent RBCs, WBCs and platelets from crossing but not proteins
Glomerular basement membrane:
Collagen IV and proteoglycans
Alport’s syndrome:
A defect in the collagen IV glomerular basement membrane, produces unusually thick membrane
Octopus like cells which coat the glomerular capillaries.
Podocytes:
Branching within podocytes:
Primary processes sprout into foot processes (which interdigitate)
Interdigitate:
Interlace, like a ziper or fingers
Slit diaphragm:
Slits between the foot processes of a podocyte. Very small, stop protein
Three filters plasma must pass through to become filtrate (in order) and mechanism for protein filtration:
Fenestrated endothelium of capillaries:
- Negative charge around pores, pushes away some protein
Glomerular basement membrane:
- Smaller, some barrier to protein
Slit membrane of podocytes:
- Stops protein from entering, very tight
Proteinurea results because:
More protein leaks through the slit diaphragm then can be pumped back by the proximal tubules
Does protein enter the proximal tubules?
Yes, it is pumped back their by active transport
What drive glomerular filtration?
Ventricular systole
Hypotension has what effect on glomerular filtration?
What might cause this hypotension?
Decreases it, increasing toxin levels in blood
Dehydration
What opposes the force of the ventricular force on glomerular filtration?
Hydrostatic pressure in the bowman’s capsule.
Does not completely oppose it. 10mmHg left over
What is the glomerular filtration rate:
The rate at which you produce urine (125 ml per minute) 45 gallons in a day!
How long does it take to filtrate our total blood volume?
40 minutes
What forces produce glomerular filtrate?
The same forces that work in other capillary beds
Extrinsic regulation of blood flow:
- Forms of it:
- Forms of it: Sympathetic innervation (fight or flight)
Obligatory water loss:
- Why?
- kind of related: what is the maximal water loss from
400 mls a day lost in urine. We cannot stop this.
- Why?
Collecting tubule can only concentrate to 1200 mOsm (the osmolality of the renal medulla)
- kind of related: what is the maximal water loss from
23 L in a day
Osmolality of filtrate is:
300 mOsm
Water and solute reabsorption in the proximal tubule:
- How?
- How much?
- How Quickly?
- Enters at ____ mOsm leaves at ____.
- How? Na+ ATPase pump moves Na out of filtrate. Cl- follows to balance charges Water follows by osmosis - How much? 65% - How Quickly? Immediately (fast) - Enters at \_\_\_\_ mOsm leaves at \_\_\_\_. 300 300
Water and solute reabsorption in the descending loop:
- Is impermeable to?
- How?
- How much?
- Enters at ____ mOsm leaves at ____.
- Is impermeable to? Na+ - How? Impermeable to Na -> renal medulla hyperosmotic -> H20 flows out -> water flows into capillaries - How much? 20% - Enters at \_\_\_\_ mOsm leaves at \_\_\_\_. 300 1200
Water and solute reabsorption in the ascending loop:
- Permeable to water?
- How is salt excreted?
- Enters at ____ mOsm leaves at ____.
- Salt excretion accomplishes what?
- Permeable to water? no - How is salt excreted? 1 Na+ moves down electrochemical gradient into cells -> 1 K+ and 2Cl- follow passively -> Na+/K+ antiporter pumps Na+ out, and K+ in -> Cl- follows by electrical attraction -> K+ diffuses passively back into the filtrate and the interstitial space - Enters at \_\_\_\_ mOsm leaves at \_\_\_\_. 1200 100 - Salt excretion accomplishes what? Increases osmolality of the renal medulla
What is the purpose of concentrating salt in the renal medulla?
It allows water to be excreted to control concentration urine
Water and solute reabsorption in the collecting duct:
- ADH:
- Where does water absorption vary?
- ADH:
ADH binds receptor -> cAMP increases -> aquaporins “exocytose” -> water can diffuse out -> collecting duct enters the high osmolarity of the renal medulla, drawing water out of the filtrate into you - Where does water absorption vary?
Here in the collecting ducts.
Where are aquaporins produced and how do they reach the membrane:
Rough ER -> golgi apparatus -> exocytosis
Beer and ADH:
Decreased ADH, large amounts of dilute urine
Reduced blood volume from blood loss will cause what in the hypothalamus?
Desire for thirst
Osmotic diuresis:
- Define:
- Example:
- Define: loss of water because of loss of high levels of salt, which water follows osmotically, increasing urine. - Example: Drinking sea water Diabetes mellitus
Renal Clearance:
- Equals:
- Equals:
Amount in glomerular filtrate - amount reabsorbed + amount secreted
Form of active transport which removes ions and particles to plasma from filtrate
Selective Reabsorption:
Form of active transport in which adds ions and particles to filtrate from plasma
Selective Secretion:
Xenobiotics are removed actively by:
Selective Secretion
