urinary Flashcards
functions of the kidney (including specifics regarding homeostatic regulation of the blood):
CHIRFPE
controls bv
homeostatic regulation of blood composition
influences bp
releases erythropoietin ,increase RBC
filters blood
produces urine
excretion of wastes
How does kidney stabilize blood pH? (homeostatic regulation of blood composition , ions, fluid balance and blood ph)
controlling excretion of H+ hydrogen ions and CO3 bicarbonate ions in the urine
homeostatic regulation of blood composition includes
ions, fluid balance, blood ph
What major wastes does the kidney filter?
nitrogenous wastes (Urea/Uric Acid, Creatinine)
the blood test to measure their level, and the condition that results when they are high
The blood test is the blood urea nitrogen, BUN
When the BUN is high, it is called
Azotemia
the anatomy of the kidney (the structures, locations, and general functions).
cacop cocacap
Renal capsule surrounds the kidney.
Renal cortex is the outer area that contains nephrons. This is where most urine production occurs.
Renal Pyramids are conical structures in the renal medulla. They hold the collecting ducts that collect urine from nephrons and channel it down towards the renal papilla/minor calyx.
Renal columns are bands of cortical tissue that go between the pyramids out to the cortex. The columns provide a path for vessels to get out to the cortex.
minor calyx collects urine from the renal pyramid and funnels it towards the major calyx. Multiple minor calices merge to form the major calyx.
major calices merge to form the renal pelvis. renal pelvis is the large funnel shaped structure that funnels urine into the ureter.
flow of BLOOD through the kidney
renal artery
segmental artery
Interlobar artery
arcuate artery
interlobular artery
Then blood flows into the afferent glomerular arteriole
glomerulus
out of efferent glomerular arteriole
peritubular capillaries
venule
interlobular vein
arcuate vein
interlobar vein
renal vein
What type of capillaries make up glomerulus?
fenestrated capillaries
What type of cells surround glomerulus?
Podocytes
What vessels bring blood into and out of the glomerulus?
Afferent arteriole goes in and efferent arteriole goes out.
Which of the 2 vessels in glomerulus is smaller and why does that matter?
Efferent arteriole brings blood out of the glomerulus. It is smaller than the afferent. This makes it harder for blood to leave the glomerulus so there is increased pressure in the glomerulus (pushes out to drive filtration).
3 layers of the filtration membrane in the glomerulus
Endothelial cells, dense layer, podocytes
Which things pass through the filtration membrane of glomerulus and which things remain in the blood?
Small things like water, ions, amino acids, fatty acids, and glucose are pushed thorough from the blood into the capsular space. wigaf
Large things like plasma proteins and blood cells remain in the blood and do not enter the urine.
flow of FLUID through the kidney
Capsular space
PCT
nephron loop
DCT
Collecting duct
Papillary
Minor calyx
Major calyx
Renal pelvis
Ureter
Bladder
Urethra
cortical nephrons :
location
structure
function
Location: cortex
structure: short loop of henle / nephron loop
Materials reabsorbed enter peritubular capillaries
juxtamedullary nephrons:
Location
structure
Function
Location: medulla of the kidney
structure: long loop of henle / nephron loop
Materials reabsorbed enter the vasa recta
Function: allow the body to excrete concentrated urine. They allow for the reabsorption of more water so the water isn’t lost in the urine.
What is the primary function of the PCT?
and How is water reabsorbed?
REABSORPTION of nutrients, ions and water
diffusion
Describe the reabsorption that occurs in the LOH/nephron loop (include the different processes that occur in the descending limb versus the ascending limb and the permeability of each segment).
The LOH/nephron loop is for reabsorption of
Na+ Cl- and water.
Water , osmosis -descending limb
(impermeable to solutes & ions, ONLY WATER IS permeable)
Na/Cl, water -ascending limb via active transport.
is permeable to water and impermeable to solutes
descending limb
A major function of the DCT is
“selective reabsorption”
What does this “selective reabsorption” mean?
and what hormones act in this segment?
Reabsorption of ions or water occurs but ONLY if a particular hormone is present.
What hormones act in this segment? Calcitonin, Parathyroid Hormone (PTH), Aldosterone, Antidiuretic Hormone (ADH)… ADH really works in the collecting duct too.
What are the functions of those hormones in the selective reabsorption?
Calcitonin: Decreased reabsorption of calcium to promote the loss of calcium in the urine.
PTH: Increased reabsorption of calcium to recover calcium from the urine back into the body.
Aldosterone: Increased reabsorption of sodium (Na+) and excretion of potassium (K+).
ADH: Inserts aquaporins into the DCT and collecting duct to allow water to be reabsorbed from the urine. This decreases urine volume and allows us to conserve water.
hormones that Decreased reabsorption of calcium to promote the loss of calcium in the urine.
calcitonin
hormones that Increase reabsorption of calcium to recover calcium from the urine back into the body.
PTH
hormones that Increase reabsorption of sodium (Na+) and excretion of potassium (K+).
Aldosterone
hormones that Inserts aquaporins into the DCT and collecting duct to allow water to be reabsorbed from the urine. This decreases urine volume and allows us to conserve water.
ADH
Overall, the reabsorption of most of the filtrate volume occurs in what part of the nephron?
Proximal Convoluted Tubule, PCT
is the water reabsorption that doesn’t happen on its own. This is the reabsorption that occurs in the DCT and COLLECTING DUCT in the presence of ADH. This water reabsorption has to be facilitated or helped by ADH (think facilitated = facultative).
Facultative water reabsorption
a reabsorption that water must be reabsorbed. This is the water that is reabsorbed in the PCT and LOH. It cannot be prevented (obligatory, like obligated).
Obligatory water reabsorption
an endocrine structure that secretes erythropoietin, renin and causes afferent arteriole constriction
JGC
the JGC is formed by?
Macula densa of DCT and
juxtaglomerular cells of afferent arteriole
is responsible for maintaining a homeostatic GFR
JGC
is released when the GFR is too HIGH
Adenosine
is released when the GFR is LOW.
Renin
The overall effects of the Renin-Angiotensin-Aldosterone system are to
increase blood pressure
increase Blood Volume
its overall effects are to increase blood pressure and to increase Blood Volume
Renin-Angiotensin-Aldosterone system
What are the specific functions of Angiotensin II?
It constricts the efferent arteriole to increase the pressure in the glomerulus (thus increase GFR). It stimulates the reabsorption of sodium ions and water in the PCT to increase BV & BP. It stimulates thirst (to increase BV). It causes systemic vasoconstriction to increase BP. Angiotensin II also stimulates the release of 2 other hormones that will complement its action: Aldosterone and Antidiuretic hormone.
What hormone is released from the kidney when oxygen delivery to the kidneys decreased?
Erythropoietin
What does erythropoietin do?
Stimulates red blood cell production in the bone marrow.
Stimulates red blood cell production in the bone marrow.
erythropoietin
it is when The plasma concentration above which a specific compound starts to appear in the urine
renal threshold
What happens if blood concentrations are above the renal threshold?
The compound will be present in the urine.
Glycosuria is when glucose appears in the urine.
Aminoaciduria is when amino acids appear in the urine.
when glucose appears in the urine
glycosuria
when amino acids appear in the urine
aminoaciduria
Why does compound like glycosuria, aminoaciduria appears in urine ,why does it happen?
When the blood concentration of the compound is so high, a ton of it gets pushed out of the blood into the filtrate (in the nephron). As that filtrate flows through the PCT, there is too much of the compound (like glucose or amino acids) for all of it to be reabsorbed. All the transporters are being used but there is still some of the compound that stays in the nephron and never gets reabsorbed. It ends up being released from the body in the urine.
Compare the renal threshold for glucose and AA (Is it more “normal” for one to appear in the urine?).
The renal threshold for glucose is much higher than the renal threshold for amino acids. You’re more likely to see amino acids in the urine than glucose. Glucose is only in the urine when something is wrong (like diabetes).
Glycosuria is associated with what disease? why?
Glycosuria is associated with Diabetes.
with high blood glucose concentrations. The blood glucose is so high (over the renal threshold) that it overwhelms the transporters in the PCT and some glucose remains in the urine instead of being reabsorbed.
Which filtration pressure pushes fluids out of glomerular capillaries (i.e. drives glomerular filtration)?
Hydrostatic pressure (capillary hydrostatic pressure)
What filtration pressure pushes fluids in to glomerular capillaries (opposed glomerular filtration)?
Osmotic pressure (blood colloid osmotic pressure)
Define Glomerular Filtration Rate, GFR:
The amount of filtrate the kidneys produce each minute (both kidneys). Note: This is NOT the amount of urine that the kidneys produce. A lot of fluid gets reabsorbed so the GFR is much higher than urine production.
Changing what factors may change the GFR?
Glomerular blood pressure or blood flow
If glomerular blood flow or blood pressure decreases, what happens? (according to autoregulation of GFR)
The nephron compensates by causing dilation of the afferent arteriole and glomerular capillaries (this brings more blood into the glomerulus). They also cause constriction of the efferent arterioles (this makes it harder for blood to leave the glomerulus and creates a back pressure). Overall, this increases the pressure in the glomerulus and increase GFR back to normal.
If glomerular blood flow or blood pressure increases, what happens? (autoregulation of GFR)
If glomerular blood flow or blood pressure increases, what happens? Constriction of the afferent arteriole (which decreases glomerular blood flow and pressure and so decrease GFR back to normal).
Natriuretic Peptides (hormonal regulation):
- ANP is released from the ______
atria
___ is released from the ATRIA.
ANP
____is released from the VENTRICLES
BNP
BNP is released from the____
ventricles
What causes the release of ANP,BNP ?
Excess stretching of the walls of the heart. This happens when there is too much blood volume.
What are the effects of ANP,BNP release in the nephron? (Natriuretic Peptides (hormonal regulation)
afferent arteriole: Dilation
efferent arteriole: Constriction
glomerular pressure: Increases
GFR: Increases
NA+ and Cl- reabsorption: Decreases
overall this promotes fluid loss and decreased blood volume.
Micturition:
Urination
process of Eliminating large volumes of urine
Diuresis
Drugs that stimulate diuresis (stimulate urination of large volumes of fluid).
diuretics
Microscopic examination of the urine
urinalysis
Urine should be clear (not cloudy), sterile, yellow, should be free of glucose, proteins, and blood cells (that means there should NOT be glucose or protein or blood cells) Waste products like urea and creatinine are present.
___carry urine from kidney to bladder.
Ureters ,Enter bladder at an oblique, slit like opening to prevent backflow of urine into ureter.
Regular _____ contractions push urine along ureter.
peristaltic
____ stores urine: Has rugae, folds in mucosa that disappear upon filling of the bladder.
Bladder
structure and function of the Trigone:
Triangle shaped area of smooth tissue at the back & bottom of the bladder. Triangle is formed by the 2 openings of the ureters (ureteral orifices) and the 1 entrance into the urethra.
Functions to funnel urine down towards the urethra (where it exits the bladder).
Internal urethral sphincter:
-Location:
- Type of muscle:
- Is it voluntary or involuntary?
Internal urethral sphincter:
-Location: Neck of the bladder
- Type of muscle: Smooth muscle
- Involuntary (NOT under our conscious control)
External urethral sphincter:
-Location:
- Type of muscle:
- Is it voluntary or involuntary?
External urethral sphincter:
-Location: Where the urethra passes through the urogenital diaphragm (the pelvic floor)
- Type of muscle: Skeletal muscle
- Voluntary (we can consciously control this to choose when we release urine)
The urethra is longer In men than in women why?
because it passes through the length of the penis
