Urinary System Flashcards
Main functions of the urinary system
Maintains homeostasis by
filtering the blood,
reabsorbing nutrients
and secreting wastes like
Urea
Amomnia and
Creatinine
As urine
What does the pituitary secrete
Hormones
Other functions of the urinary system
- Regulates blood volume (by conserving or secreting less or more water)
- Regulates blood pressure ( by secreting renin, activating the RAAS system increasing blood presssure
- Regulates blood PH ( by excreting H+ ions or conserving HCO3 -ions)
- Regulates blood glucose levels :
- Helps maintain concentrations of electrolytes like Na+, K+, Ca2+, Cl-, HPO4 3-, Mg 2+ and HCO3-
- Maintains blood osmolarity
- Production of hormones
How much urine do we produce on average in a day?
1-2 litres
Medical term for urination is
Micturition
how much can the bladder hold?
700-800 mls
What does caffiene and alcohol inhibits/stops what hormone?
ADH
Anti- diuretic hormone
Renal hilum-what does it contain?
Contains
renal pelvis,
calyces,
blood vessels
and nerves
Renal cortex
Superficial outer region,
functions to filter the blood to form urine
Renal medulla (pyramid)
Deep inner region, function to collect and concentrate urine, then excrete it
Renal papilla
Where pyramids empty urine into minor and major calyces, become urine here.
Papillary ducts
Receives urine from the minor and major calyces
Glomerulus
What is it composed of?
What happens here?
Composed of a capsule and capillaries, blood is filtered here through a leaky membrane
Glomerular capsule or bowman’s capsule what does it contain- describe wall
Surrounds the glomerular capillaries:
Visceral layer : inner wall, contains podocytes with pedicels that wrap around the capillaries
Parietal layer : forms the outer wall of the capsule
Glomerular capillaries…3 layers
Have 3 layers called “filter action membrane”
1. Fenestrations: endothelial cells are very leaky, allows everything except blood cells through
2. Basement membrane: basal laminate made of collagen with holes in it, allows water, small solutes, small proteins through
3. Podocytes with pedicures: foot like processes that form filtration slits, allows smaller proteins, water and vitamins through
what elements does urine excrete
Urea
Amomnia and
Creatinine
As urine
Nephron and renal
Both mean kidney
Latin and?
Cortex meaning
Outside
Internal and external urethral sphincter which one is voluntary and not?
Internal= involuntary- always closed - don’t have to think about it
External = choose to pee- external
Chemoreceptors detect levels of what?
Oxygen
Carbon dioxide
Hydrogen ions (ph)
How much fluid does the urinary bladder hold on average?
700-800ml
Which levels of the spinal cord control the micturition reflex?
S2
S3
Which layer of the bladder contains the internal sphincter?
Middle
Which of the following is not a part of the hilum?
Renal artery
Renal vein
Renal calyces
Renal pelvis
Renal nerves
None of the above?
None of the above
Which layer of the bladder contains the internal sphincter?
Middle
Which hormones INCREASE filtration rate?
ANP
atrial natriuretic hormone
The micturition reflex involves- explain what is involuntary and voluntary- contraction vs relaxed
Involuntary relaxation
Of the
Internal sphincter
Which hormones DECREASE glomerular filtration rate?
angiotensin 2
What is the order that filtrate passes through a nephron?
Proximal convoluted tubule
Descending limb
Ascending limb
Distal convoluted tubule
Collecting duct
The juxtaglomerular apparatus is made up of?
Macula cells
Juxtaglomerular cells
Urea is reabsorbed and recycled predominantly from where?
Collecting duct
What is NOT secreted into the filtrate at the proximal convoluted tubule?
Glucose
What is secreted into the filtrate at the distal convoluted tubule?
K+
H+
Potassium and hydrogen
The measure of how many solutes are in a solution is that solutions……..?
Osmolarity
In tubular reabsorption
Which method of transport utilizes symporters and antiporters?
Secondary active transport
Which fraction of water is RE-absorbed in the loop of henle?
15%
Fenestrations- what are they? Where are they?
Glomerular endothelial cells
Are very leaky
Allows everything
except blood cells
to filter through
The glomerular filtration membrane has 3 distinctive layers-
What are they?
And
What can get through each layer?
Fenestrations - very leaky- everything but RBC
Basement membrane - collagen with holes allows water and small solutes or small proteins
Podocytes with Pedicels allow smaller proteins, water, vitamins to filter through
What are the 5 layers of the walls of the ureter?
Mucosa
Lamina
Propria
Muscularis
Adventitia
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What are the 3 muscle layers of the urinary bladder?
Muscularis layer = detrusor muscle
Made of 3 layers of
smooth muscle
Inner longitudinal
Middle circular- these form an internal urethral sphincter involuntary
Outer longitudinal - voluntary control
Path of urine drainage?
Nephron
Collecting duct
Papillary duct
Minor calyx
Major calyx
Renal pelvis
Ureter
Urinary bladder
Urethra
What is the order of blood supply - kidneys
Renal artery off the ABD aorta into the hilum
Segmental arteries
Interlobar
Arcuate
Cortical radiate
Afferent arterioles
Glomerular capillaries efferent arterioles
What is the visceral and parietal layer of the bowman’s (glomerular) capsule?
Visceral layer- Inner wall contains podocytes and pedicels that wrap around glomerular capillaries
Parietal layer- outer wall
Why in the loop of Henle (nephron) does it have a part that is thinner?
The thin part of the loop of Henle is lined by simple squamous epithelium.
The thin limb is divided into two parts:
the ascending
and
descending limbs - The descending limb is highly permeable to water, but not to salt.
Permeability is largely dependent on the concentration of Aquaporin 1 in the epithelium.
What is the Juxtaglomerular apparatus (JGA)made of?
What are all the cells involved?
Juxtaglomerular Apparatus (JGA):
made up of
macula densa
and
juxtaglomerular cells
Macula Densa Cells : specialized cells in the ascending limb of Loop of Henle.
Juxtaglomerular Cells : modified smooth muscle fibres that are specialized cells in the wall of the afferent arteriole.
What is Glomerular blood hydrostatic pressure?
Capsular hydrostatic pressure &
Blood colloid osmotic pressure?
Glomerular blood hydrostatic pressure - promoting filtration Pushing solutes out of the blood into the bowman’s capsule
opposing filtration
Capsular hydrostatic pressure
Blood colloids osmotic pressure
What is
Dysuria
Enuresis
Nocturnal enuresis
Polyuria
Uremia
Dysuria: painful urination
Enuresis: involuntary voiding
Nocturnal enuresis: night time bed wetting, young children (up to 5) Polyuria: excessive urination
Uremia: toxic levels of urea in the bloodstream
What are the 2 types of nephrons?
Juxtamedullary nephron
Cortical nephron
What percentage of nephrons is juxtamedullary nephrons?
15-20 %
What percentage of nephrons are cortical nephrons?
80-85%
Tubular reabsorption
Primary active transport- what is it?
ATP fuels the Na+/K+ pumps
Tubular reabsorption
Secondary active transport- what is it?
Secondary active transport:
symporters move 2 or more substances in the same direction,
anti-porters move 2 or more substances in opposite directions
Numbers for reabsorption in the
Proximal convoluted tubule
Descending loop
Distal convoluted tubule
Proximal convoluted tubule - 65%
Descending loop 15%
Distal convoluted tubule- 20%
Where is the most salty place in the nephron?
PCT
What is Na+
Sodium
Hat is K+
Potassium
Ca2+
Calcium
HCO3-
Bicarbonate
Mg2+
Magnesium
Cl1-
Chloride
P?
Phosphorus
What cells produce Renin?
Juxtaglomerular cells
What makes the ascending loop of henle unique?
No water can go through it
Why are podocytes with Pedicles (foot like processes) structurally the way they are?
Foot like processes form filtration slits allowing smaller proteins
Water
Vitamins
Through
What is a simple blood pressure explanation?
Pushes the
solutes out of the blood through the filter action membrane
into the
capsule and capsular pressure
and
blood colloid pressures pushes back
