Urinary system Flashcards
What metabolic waste products are exreted in the urine?
- Urea
- Creatinine
- Uric acid
- Bilirubin
What does urea come from?
The breakdown of amino acids
What does creatnine come from?
The breakdown of creatine phosphate in muscles
What does uric acid come from?
The catabolism of nucleic acids
What does billirubin come from?
The catabolism of hemoglobin
Generally, how does the urinary system regulate blood volume?
By conserving or elminating water in urine
What controls blood composition?
- Na
- K
- Ca
- Cl
- Phosphate ions
Generally, how does the urinary system regulate blood pressure?
Secretion of renin
Generally, how does the urinary sytem regulate blood pH?
- Extretion of H+ions in urine
- Conservation of bicarbonate ions in blood
Generally, how does the urinary system regulate blood glucose levels?
By producing and releasing glucose into the blood (much like the liver)
How does the urinary sytem regualte calcium homeostaisis?
By producing calcitrol (active form of vitamin D)
What does erythorpoietin cause in the urinary system?
Stimulates the production of RBC
Is sodium an intercellular or extracellular fluid?
Extracellular
Is potassium an intracellular fluid or an extracellular fluid?
Intracellular fluid
What ion repolarizes the membrane potential?
Potassium
What kidney is more inferior and why?
The right kidney is more inf. because of the liver
What part of the kidney is most posterior?
The superior part
What vertebral level are the kidneys located at?
T12-L3
How do we best demonstrate the right kidney?
LPO oblique of 30 degrees to make it parrellel to the IR
Which way are the kidneys obliqued naturally?
Obliqued 30 degrees anteriorly
What are the kidneys protected by?
Ribs 11 and 12
In situ, what structures are located anterior to the right kidney?
- Right lobe of liver
- Descending duodenum
- Hepatic flexure
- Ascending colon
In situ, what structures are located anterior to the left kidney?
- Tail of pancreas
- Stomach
- Splenic flexure
- Descending colon
What type of exam is this?
KUB contrast
Label 3-6
- Ascending colon
- Descending colon
- Abominal aorta
- IVC
What is the renal capsule?
The inner most layer surrounding the kidney
What are the 3 layers that surround the kidney from deep to superficial?
- Renal capsule
- Adipose capsule
- Renal facia
What is the adipose capsule?
The middle layer surrounding the kidney
What is the function of the adpose capsule?
Protection and to help hold the kidney in place
The dropping of the kidney by 2in/5cm from supine to erect is refered to as what?
Ptosis
What body type is ptosis greatest with? Why?
Asthenic body types because they have the least amount of fat to hold the kidneys in place
What is the renal capsule?
The outermost, dense tissue layer that surrounds the kidneys
What does the renal fascia connect the kidney to?
- Abdominal wall,
- lumbar vertebrae,
- diaphragm
What is the renal cortex?
The outer layer of the inside of the kidneys
What is the renal column?
The anchor for cortex located between the renal pyrimids that allow for the passage way for vessels
What is the renal medulla?
The inner layer of the kidney that consists of series of pryimids
What are the renal pryramids? How many do we have on average?
Cone-shaped structures located within the medulla
-We have 8-18 on average
What is the renal papilla?
The distal part of the pryamids that drain into the minor calyces
How many minor calyces do we have on average?
8-18
What do the minor calyces drain into?
The major calyces
How many major calyces do we have on average?
2-3
What do the major calyces comine to form?
Combine to form the renal pelvis
What is the renal hilum?
The indented area on the medial side of the kidney
What does the renal hilum contain?
- Renal artery
- Renal vein
- Ureter
- Nerves
- Lymphatics
What are the 2 main parts of the nephron?
- Renal corpuscle
- Renal tubule
How many nephrons do we have on average?
1 million/kidney
What is the nephron? Where is it located?
The functional unit of the kidney located in the renal cortex AND the renal medulla (pyramid)
What part of the nephron is located in the medulla?
The loop of henle
During inspiration, which way does the kidney move?
Down
During expiration, which way does the kidney move?
Up
What is a renal lobe?
1 pyramid that consists of everything from the minor calyx to the renal cortex
How many renal pelvis’ do we have?
1
How many ureters do we have?
Only 1
What does the renal pelvis drain into?
The ureter
What are the 2 parts of the renal corpuscle in the nephron?
- Glomerulus
- Bowmans capsule/glomerular capsule
What occurs in the renal corpuscle?
Blood plasma is filtered from glomerular capillaries to the the glomerular capsule/bowmans
What is the glomerulus?
A network of capillaries surrounded by the bowmans capsule
What is the bowmans capsule?
A double-walled cup that surrounds the glomerulus
What are the 3 parts of the renal tubule?
- Proximal convoluted tubule
- Loop of henle (nephron loop)
- Distal convoluted tubule
What is the pathway of blood starting at the renal arteries?
- Renal arteries
- Segmental artery
- Interlobar artery
- Arcuate arteries
- Cortical radiatiate arteries
- Afferent arterterioles
- Glomerulus
- Efferent arteriole
- Peritubular capillaries
- Cortical radiate veins
- Arcuate veins
- Interlobar veins
- Renal vein
What percentage of the resting cardiac output do the kidneys recieve?
20-25%
Which renal arteries is longer?
The right
How many renal arteries do we have in total (both sides)
2 in total
How many segmental arteries are there?
Supplies one to each segment
Where does the the segmental arteries and interlobar arteries pass through?
The renal columns
Where are the arcuate arteries located?
The arch between the renal medulla and cortex
Where do the cortical radiate arteries radiate towards?
Radiate outwards into the renal corex
How many afferent arterioles do we have?
1 per nephron
What is the function of the efferent arteriole?
Carries blood away from the glomerulus
Where are the peritubular capillaries located?
They surround the tubular parts of the nephron
Which arteriole is larger; the efferent or the afferent?
The afferent
What arteriole has higher pressrure; efferent or afferent? Why?
The afferent arteriole because of the increase in its size
Check
What are the 2 types of nephrons?
- Cortical nephrons
- Juxtamedullary nephrons
What percentage do the cortical nephrons make up?
80-85%
What percentage of nephrons do the juxtamedullary nephrons make up?
15-20%
Where is the renal corpuscle located in the kidney?
Lies in the outer part of the renal cortex
True or false?
The jextamedullary nephrons have a short loop of henle.
False; long
True or false?
The cortical nephrons have a short loop of henle.
True
Where are the renal corpuscles in juxtaglomerular nephrons?
Deep in the renal cotex (close to the medulla)
What additional blood supply do juxtaglomerular nephrons have that cortical nephrons do not?
The vasa recta
What are the 2 parts of the loop of henle in juxtaglomerular nephron?
- Thick portion
- Thin portion
What is the purpose of the juxtaglomerular nephrons having a long loop of henle?
Aloows the kidneys to excrete very dilute or very concentrated urine
True or false?
The glomerulus is very leaky and lets out allows all of the solutes to leak out into PCT.
False; it is very leaky but does not allow blood cells to leak out
What are the 2 layers to the glomerulus?
- Parietal
- Visceral
What is located between the visceral and parietal layers of the bowmans capsule?
The capsular space where filtrate is collected
What is blood called as it goes from the glomerulus to the bowmans capsule?
Filtrate
What are the two parts of the loop of henle?
- Decending loop
- Ascending loop
Where is the macula densa located?
On the acending loop in contact with the afferent arteriole
What are the juxtaglomerular cells and where are they located?
They are smooth muscle fibers located along the sides of the afferent arteriole and the macula densa.
(next to the glomerulus)
What is the juxtaglomerular complex?
The macula densa+juxtaglomerular cells that helps to regulate blood pressure within the kidney
What are the two cell types within the distal convoluted tubule?
- Prinicpal cells
- Intercalated cells
What is the function of the prinicpal cells?
They are the receptors for anti duretic hormone (ADH) and aldostrone
What is the function of the intercalated cells?
Regulates homeostasis of the pH of blood
What are the three steps that fluid takes as it goes through the nephron?
- Glomerular filtration
- Tubualr reabsorption
- Tubular secretion
True or false?
Volume of fluid filtered by the renal corpuscle is much lesser than other capillaries
False; Volume of fluid filtered by the renal corpuscle is much greater than other capillaries
What allows the glomerulus to filter so much fluid?
- Large surface area
- Thin and purous filtration membrane
- High glomerular blood pressure
What controls the surface area in the glomerulus?
Mesangial cells
When the mesangial cells are relaxed; what does this indicate about the surface area and filtration?
Maximal surface area and filtration occuring
When the mesangial cells are contracted; what does that indicate about the surface area and filtration?
Minimal filtration and surface area occuring
How wide is the filtration membrane in the renal glomerulus?
.1mm
True or false?
The glomerulus is 50 times less leaky than other capillaries.
False; 50 times more
What happens during tubular reabsorption?
Water, ions and other substances get reabsorbed from the renal tubule lumen into the peritubular capillaries and ultimetly into the blood.
What happens during tubular secretion?
Wastes, drugs and excess ions get secrted from peritubular capp. into the renal tubule. These substances ultimetly make their way into the urine.
Where is tubular reabsorption and secretion occuring?
In the renal tubule and collecting duct
True or false?
The pores of the glomerular cells alllow components of blood plasma to pass through.
True; just not blood cells themselves
How do you calculate net filtration pressure (NFP)?
GBHP-CHP-BCOP=10
What is glomerular blood hydrostatic pressure?
GBHP
Most responsible for the formation of filtrate and forces water and solutes through the filtration membrane
What is the pressure in the glomerulus? Why is there so much pressure?
55mmHg-because the afferent arteriole is larger than the efferent arteriole
What is capsular hydrostatic pressure?
CHP
The back pressure exerted by fluids already in the capsular space as the fluid is being pushed out of the glomerulus
What is the capsular hydrostatic pressure?
15mmHg
What is blood colliod osmotic pressure?
BCOP
The presenece of protiens in the blood that cannot pass through the membrane, and the final result is it tries to pull water into the blood stream
What is the blood colloid osmotic pressure?
30 mmHg
If the GBHP is below 40 mmHg, what will occur?
NO FITLRATION
If the afferent arteriole dialates, what will occur to NFP?
A greater NFP will occur
If the efferent arteriole constricts, what will occur with the NFP?
A greater NFP will occur
What is glomerular filtration rate?
The amount of filtrate formed by both kidneys each minute that measures how well the kidneys are working
What is the average glomerular filtration rate in both males and females?
Males: 125 mL/min
Females: 105 mL/min
How many L of fluid are filtered out by the kidneys in an average male per day?
DO MATH EQUATION
180L of fluid filtered out by kidneys per day in an avereage male
Can we measure Glomerular Filtration Rate (GFR)
No
What test do we do since we cannot measure the glomerular filtration rate?
An eGFR blood test to measure the creatinine levels
True or false.
GFR increases with age.
False; GFR decreases with age
What factors affect creatnine levels?
- Age
- Gender
- Race (black or other)
What is the realtionship between GFR and NFP?
Directly related
How is GFR regulated by?
- Adjusting the blood flow into and out of the glomerulus
- Altering the glomerular capillary surface area avalible for filtration
If the GFR is too high, what does that mean?
Needed substances are lost within the urine since they have been filtered out into the bowmans capsule (i.e. protiens make thier way into urine)
If the GFR is too low, what does that mean?
Waste products in the glomerulus are not exreted into the urine as they should be.
What is GFR controlled by?
- Renal autoregulation
- Neural regulation
- Hormonal Regulation
When does renal autoregulation occur?
Occurs at all times
The kidneys look after themselves
How do all mechanisms of controlling GFR work?
They work by:
1. Adjusting the blood flow into or out of the glomerulus
2. Altering the glomerular capillary surface area
Do black people have higher or lower creatnine levels?
Black people have higher creatnine levels
What is the function of autoregulation?
- Helps the kidneys to maintain a normal blood flow and GFR even during excercise
When is GFR nearly constant?
When the mean arterial blood pressure is anywhere between 80-180 mmHg
What are the 2 mechanisms of autoregualation?
- Myogenic mechanism
- Tubuloglomerular feedback
What is the myogenic mechanism?
Myogenic=muscle
If blood ressure rises, stretch receptors trigger the smooth muscle cells to constrict in the afferent arterioles and blood pressure drops.
The opposite occurs when blood pressure is too low
What is tubuloglomerular feedback?
The macula densa provides feedback to the glomerulus by detecting increases in Na+Cl and inhibits the relase of nitric oxide from cells in the juxtaglomerular apparatus and thus causes constriction of the afferent arterioles.
If there is increased Na+Cl within the glomerulus, why is this a bad thing?
Because that means there is less time for reabsorption
True or false?
Nitric oxide causes vasodilation.
True
True or false?
Tubuloglomerular feedback is much slower than the myogenic mechanism.
True
When is neural regualtion working?
Only works in extreme conditions such as a massive hemorage. At rest, this system is not controlling GFR,
What type of nerves are supplied to the kidneys?
ANS nerves
What does sympathetic nerve stimulation cause in the afferent and efferent arterioles?
Causes vasoconstriction
When blood pressure drops due to hemorrhage or severe dehydration, what does neural regulation do?
Neural regulation causes both the afferent and efferent arterioles to constrict, decreasing renal blood flow, GFR, + urine output, thus permting greater blood flow to the heart and brain
What 2 hormones are in charge of hormonal regulation?
- Angiotensin ll
- Atrial natriuretic peptide (ANP)
What is angiotensin ll and what does it do?
-It is a potent vasoconstricter
-It reduces renal blood flow in both the afferent and efferent arterioles
-It reduces GFR
What is ANP and what does it do?
-It is released from the heart when stretched
-Happens when there is too much blood volume
-Causes afferent arteriole to get bigger which increases GFR
What are the 2 types of tubular reabsorption?
- Passive transport
- Active transport
True or false?
In 45 minutes of tubular reabsorption, more fluid has entered the PCT than there is total blood volume.
True
Where is tubular reabsorption taking place and what substances of the filtrate are reabsorbed back into the blood stream?
-Takes place in the PCT
-Water, glucose, protiens, urea, ions
What are the 2 types of transporters in active transport with tubular reabsorption?
- Symporters
- Antiporters
What are symporters?
Membrane protiens that move 2 or more substances in the same direction across a membrane (require E)
What are antiporters?
Membrane protiens that move 2 or more subtances in the opposite direction across a membrane (require energy)
Give 2 examples of antiporters and symporters:
- Symporters: Na, Glucose
- Antiporters: Na, H+
How much water is being reabsorbed during water reabsorption
99% of water reabsorbed
What are the 2 types of water reabsorption?
- Obligatory water reabsorption
- Facultative water reabsorption
What type of transportation does is water reabsorbed by? What drives it?
Reabsorbed through osmosis and driven by solute reabsorption
What percentage of water reabsorption is obliatory water reabsorption?
90%
What percentage of water reabsorption is facultative water reabsorption?
10%
True or false?
Water moves from high concentration to low concentration.
True
Where does obligatory water reabsorption take place?
- PCT
- Descending loop of henle
Where does facultative water reabsorption take place?
- DCT
- Collecting ducts
What is facultative water reabsorption regulated by?
ADH
What is tubular secretion?
The movement of substances from the capillaries which surround the nephron into filtrate
Where does tubular secretion take place?
- PCT
- DCT
- Collecting ducts
(at a site other the the filtration membrane)
What type of transport drives tubular secretion?
Active transport
What type of process controls pH?
1. Tubular reabsorption
2. Water reabsorption
3. Tubular secretion
Tubular secretion; by conserving biocarbonate
What compounds decrease the acidity in the blood?
Secretion of Hydrogen and amonium ions
How much water is filtered per day? (i.e. enters the glomerular capsule)
180 L
How much water is reabsorbed per day? (i.e. returned to the blood)
178-179 L
How much water is secreted per day? (i.e. to become urine)
1-2 L
How much glucose is secreted per day? (i.e. to become urine)
0g
What type of diabetes presents with sugar in the urine?
Diabetes mellitus
Should blood cells be filtered out of the glomerular capsule?
NO
What 2 processes occur in the PCT?
- Reabsorption
- Secretion
How much water is reabsorbed by the PCT?
65%
What percentage of glucose and amino acids are reabsorbed in the PCT?
Almost 100%
What ions are transported through active transport in the PCT?
- Sodium
- Potassium
- Magnesium
- Phosphate
- Sulfate
What happens during secretion in the PCT?
Na+ and H+ (antitransporters) promotes absorption of Na+ and secretion of H+
What process occurs in the loop of Henle?
Reabsorption
What ions are reabsorbed in the loop of henle?
- Sodium
- Potassium
- Choloride
- Calcium
- Magnesium
What percentage of water reabsorption occurs in the loop of henle?
15%
What is the descending loop of henle impermeable/permeable to?
Impermeable: To solutes
Permeable: To water
What is the ascending loop of henle impermeable/permeable to?
Impermeable: To water
Permeable: To sodium and cholride ions
What are the two parts of the loop of henle?
(including their subsections)
- Ascending (thick and thin)
- Decending (thick and thin)
By the time that filtrate has gone through the DCT how much of water and solutes are reabsorbed?
95% of water and solutes reabsorbed
What are the 2 cells located in the DCT?
- Principle cells
- Intercalated cells
What is the function of the principal cells in the DCT?
- Contains receptors for ADH and aldosterone
- Controls faculative water reabsroption
What is the function of intercalated cells in the DCT?
Homeostasis of blood pH
Watch video and take notes on countercurrent multiplicaton.
Additional notes avabile in lecture slide
What two systems are able bring the blood pressure up when blood pressure is low?
- Renin angiotensin-aldoserone system
- Antiduiretic hormone (ADH)
Describe the process of how the renin-angiotensin-aldosterone system increases blood pressure:
- Renin is released from the kidneys
- Renin activates angiotensin l (inavtive)
- Angiotensin-convertining enzyme (ACE) convertes angiotensin l to angiotensin ll
- Angiotensin ll causes constricution of the arterioles, increasing B.P.
- Ang.T. ll triggers adrenal glands to release aldostrone, increasing blood pressure
What is angiotnsin ll?
An active potent vasocontrictor
How does aldostrone increase B.P.?
It promotes sodium reabsorption which leads to water retention and thus increases B.P.
Describe the process of how ADH increases B.P.:
- Low blood pressure causes the relase of ADH from the posterior pituitary gland
- ADH promotes FACULTATIVE water reabsorption in the kidney back into the blood and thus; increases B.P.
What hormone decreases blood pressure because of increased volume?
Atrial Natriuetic peptide (ANP)
How does ANP decrease blood pressure?
- ANP released from the heart when stretched (due to too much blood V)
- Causes afferent arterioles to get bigger by signaling the kidneys
- Increase in GFR which causes more water to be released
When does filtrate become urine?
The minor calcyx
When was this image taken, and where is the contrast?
-Image taken immediatly after injection
-Contrast in the nephron (hasnt been filtered out yet)
When was this image taken, and where is the contrast?
-Image taken after 5-10 following contrast administration
-Contrast located from the minor calyces to the bladder
What muscle sits directly posterior to the ureters?
PSOAS muscle
How long are the ureters?
10-12 inches
What part of the ureter is the most anterior?
The middle part of the ureter
True or false?
Peristalsis moves the urine to the urinary bladder.
True; gravity also helps
As the ureters approach the bladder, which way do they curve, and what do they pass through?
Curve medially and passes through the posterior wall of the bladder on an oblique angle
Where do the ureters end?
The trigone
Where does the renal pelvis of the kidney meet the ureter?
The UPJ (uretropelvic junction)
Where does the ureter meet the bladder?
UVJ (urterovesicle junction)
How do we represent the right UPJ?
RPO 30 degrees
How do we represent the Right UVJ?
LPO 45 degrees
True or false;
The rugae is located in the urinary blader.
T+F; located in the urinary bladder, but NOT in the trigone
What is hydronephrosis? What can it be caused by?
-It is an acess of fluid in the bladder
-Caused by kidney stones
What are the 3 most common places for kidney stones to get stuck?
- Uretropelvic junction
- Ureterovesical juntion
Label 1-3
- Ureteropelvic junction
- Pelvic brim
- Ureterovesical junction
What are phleboliths?
Calcified veins
How much urine can be stored in the bladder?
700-800 mL
Where is the bladder located in relation to the symphysis?
Posterior to the symphysis
What structures are located in the trigone?
- 2 uretral openings
- 1 internal urethral orifice
What is the purpose of the rugae in the bladder?
Increase in EXPANSION
(NOT SA)
Label this image
Label the blue boxes in this image
Where is the bladder located in males?
Directly anterior to rectum
Where is the bladder located in females?
- Anterior to the vagina
- Inferior to the uterus
How long is the male urethra?
20 cm
How long is the female urethra?
4cm
What are the three different parts of the urethra in males?
- Prostatic urethra
- Membranous urethra
- Spongy urethra
What is the function of the urethra in males?
- Carries urine
- Carries sperm
Which way is the urethra directed in females?
DIrected inferiorly and anteriorly
Label 10, 11, 15
10=Urinary bladder
11=Urethra
15=Pubic symphysis
Label 6, 11, 12, 20
6=Spongy urethra
11=Membranous urethra
12=prostatic urethera
20=Urinary bladder
What vertebral level are the kidneys located at?
T12-L3
What pathology is shown here?
Prostate cancer
-Ostoblatic appearance