Urinary Flashcards
how much of our body weight is water both female and male
male = 60% females = 55%
how much of our TBW is intracellular and extracellular?
extra - 1/3
intra - 2/3
how does the urinary system maintain balance of the body?
by filtering blood and expelling water, salts, waste, drugs and toxin
what part of metabolism is let out as waste?
urea and drugs
how much blood flows through the kidneys per min?
1200ml
and the urine we make is 800- 2000ml per day
what is urine?
Waste product excreted to maintain balance within the body
what is the pH of urine?
4.6-8.0
what do we not want in urine?
large proteins. blood cells. glucose
what does the urine system need to do to be effective?
delivery system for blood
selective filtration system
to be able to recover things that have been filtered
return fluid back to the body
protection and storage
to coms with other parts of the body
adaptable to meet bodies needs
what are the major organs of the urinary system?
kidneys, ureters, urinary bladder, urethra
what can the kidneys do?
allows blood to be close with the nephrons for filtering
blood leaving has been filtered
protection
where are the kidneys located?
under 11th and 12th ribs
T12 vertebra and L3 vertebra
what surrounds the cortex of a kidney?
FCT
where does the urine get made?
nephrons
what are the structures that provide external protection for the kidneys?
11th and 12th rib
renal fat pad
fibrous capsule
where in the kidney does filtration occur
in the cortex
what do veins do in the kidneys?
return filtered blood from the cortex to renal vein then to the inferior vena cava
what is the afferent arteriole?
delivers blood from the arteries to the glomerulus
the peritubular capillaires carry blood to the?
veins
what is the order of blood flow through the kidneys?
into the cortex abdominal aorta renal artery series of arteries afferent arteriole glomerular capillary
which of the following structures don't pass through the hilum in the kidney? 1- renal vein 2- urethra 3- lymphatics 4- renal nerves 5- renal artery
2
functions of the nephron?
filtration, reabsorption, secretion
what makes up the walls of the glomerular capillaries?
fenstrated endothelial cells
what wraps around the renal tubules?
peritubular capillaries
what do the peritubular capillaries do?
receives reabsorbed filtrate from the nephron
What is the vasa recta?
extensions that follow the nephron loop deep into the medulla but only found in jux nephrons
What is the renal corpuscle?
where the capillary and the nephron meet
and the site of filtration barrier
what is bowman’s capsule?
First part of nephron where filtrate is collected
what are the two layers of the glomerular capsule?
parietal layer of simple squamous cells
and visceral layer of podocytes
what is the capsular space?
Space in-between the Bowman’s Capsule and Glomerulus which receives the filtrate
What are podocytes?
cells in the Bowman’s capsule in the kidneys that wrap around capillaries of the glomerulus
these have filtration slits between to filter blood to the capsular space
what surrounds the proximal convoluted tubule
peritubular capillaries
what is the structure of the proximal convoluted tubule?
cuboidal epithelial cells
microvilli
highly folded basolateral membrane
many mitochondria
leaky epithelium
what is the anatomical structure of Distal convoluted tubule?
NO BRUSH BORDER
few mito
influenced by aldosterone
what cells make up the collecting duct
cuboidal
what are principle cells?
reabsorption
what are intercalated cells?
acid/base balance
what causes reabsorption in the collecting duct?
ADH and aldosterone
What is the juxtaglomerular apparatus (JGA)?
Specialised zone in every nephron
controlling glomerular filtration rate and stabilises blood pressure
what two cells are in the juxtaglomerular?
macula densa cells (DCT) juxtaglomerular cells (afferent arteriole)
what cells form the visceral layer of the glomerular capsule called? 1- pedicels 2- podocytes 3- mesangial cells 4- filtration slits 5- macula densa
2
the cells of the JGA on the afferent arteriole are called? 1- juxtaglomerullary 2- macula densa 3- mesangial cells 4- juxtaglomerular 5- podocytes
4
what two epithelial cells would you find in the nephron loop?
cuboidal and simple squamous
what is transitional epithelium?
Stratified - rounded cells
Flattened when stretched
For protection
what are the three layers of the ureters?
transitional epithelium
muscularis (inner long and outer circle)
adventitia (FCT)
folded protein plaques
where are the long and smoith muscle in this layer?
long is on the inside and it is circular on the outside
the Gi tract is the opposite way round
why is the ureter running obliquely through the bladder wall ?
to act as a sphincter as when the bladder increases it blocks the pipe due to it being full of urine and to prevent back flow
how much can the bladder expand?
500ml
and goes above the pubic symphysis
more spherical
why do we get bladder infections?
when the water gets pooled in the trigone and isnt released out when peeing
Where is the male bladder located?
The male bladder is located above the prostate gland in front of the rectum.
where is the female bladder located?
anterior to vagina and uterus
in front
what are the layers of the bladder wall?
mucosa (transitional ep) , submucosa, detrusor (thick smooth muscle), visceral peritoneum
what three structures protect the urinary tract?
- transitional epithelium
- protein plaques
- entrance to bladder prevents back flow
what is the name of the muscles that form the wall of the bladder? And what is its function?
detrusor muscle
expels urine
what are the epithelial changes in the uretha
transitional near the bladder
columnar
stratified squamous
what are the 3 sections in a male urethra?
prostatic, membranous, spongy/penile
job of the internal urethra sphincter?
detrusor muscle
involuntary control
this opens when the bladder contracts
what statement is incorrect about the bladder?
1- detrusor muscle forms the bladder wall
2- lined with transitional epithelium
3- collapsible sac which stores urine
4- the trigone is a triangular area between the openings of the ureter and the urethras
5- when emptying, the bladder collapses along folds called rugae
4
what three places in the urinary tract would you find transitional epithelium?
ureters, urinary bladder, initial part of the urethra
what is normal urine made out of?
water creatinine urea h, nh3 na k drugs toxins
what would you see in unhealthy urine?
glucose protein haemogolbin leuocytes bacteria blood
what is the effect of the diet on ph?
vegetarians have a 7.2
meat-eaters have a 4.8
normal urine? 1- amino acids 2- 20 L per day 3- does not contain H ions 4- contains Na and K 5- tastes sweet
3
what are the general functions of the kidney?
hormone production filters blood metabolism ph regulation reabsob nutrients excretion of drugs and toxins salt and ion homeostasis water homeostasis
What is erythropoietin (EPO)?
hormone that stimulates RBC production
when low O2 levels are detached by kidney it release EPO to stimulate more RBC creation
chronic renal failure (CRF)
anaemia (low level of rbc therefore low o2 levels)
what is salt ion homeostasis good for?
- action potentials
- rhythm generation in pace maker cells
- contractions
- signalling
what is excreted by the kidneys after metabolism in the liver?
lidocaine
what is secreted directly by the kidneys?
aspirin
what controls bicarbonate concentration in the blood?
by the lungs (exhalation of CO2) and the kidneys by reabsorbing it or the secretion of H ions
which of the following is not a function of the kidney? 1- gluconeogenesis 2- secretion of glucose 3- filtration of blood 4- K reabsorption 5- drug secretion
2
where is glucose only reabsobed?
proximal tubule
Does the renal proximal tubule facilitate? 1- fine tunning 2- secretion of k 3- reabsorption of drugs 5- filtration of blood 6- secretion of drugs and metabolites
6
salt and water control what?
blood pressure
what kind of filtration is in the nephron?
ultrafiltration
how fast is filtration?
125ml/min (180L/day)
how much urine do we produce in a day?
1.5L
What defines renal filtration?
renal blood flow, filtration barrier, driving forces
when does the juxtaglomerular apparatus secrete renin?
when glomerular pressure in the blood decreases
where is the primary urine is made?
capsular space
how much blood do the kidneys get from the cardiac output?
25%
what determines filtration?
- pressure gradients between glomerular capillary and capsular space
- permeability of glomerular capillary
- surface area
what are the 2 driving forces for glomerular filtration(capillary exchange)?
glomerular hydrostatic pressure (GHP)
capsular hydrostatic pressure (CsHP)
What are 2 opposing forces in capillary exchange (glomerular filtration) ?
1) capillary hydrostatic pressure(CHP)
2) blood colloid osmotic pressure (BCOP)
filtration of the kidney…
1- dependant on osmotic force in the capsular space
2- results in high protein load of the primary urine
3- results in an isotonic primary filtrate
4- results in an absence of glucose in the primary urine
5- is independent of serum albumin
3
renal clearance equation
Cx = UsV/Ps
us - concentration of s in urine (s = substance)
v- volume of urine produced per unit time
ps= concentration of s in plasma
what does the clearance equation tell us?
the rate at which the substance S is cleared by the kidneys per unit time
what does s stand for?
all substances we can detect in the plasma
what does the glomerular filtration rate (GFR) measure?
amount of fluid filtered per unit time
what must the substance have to measure GFR?
not to be reabsorbed from tubule
not be secreted into tubule
not metabolised
what substances can you use to measure GFR?
inulin and creatine
what is inulin?
Polysaccharide that is not absorbed by the renal system and is ejected in the urine
what is creatine?
waste product of muscle metabolism
already in the body
why can we use creatinine for measuring GFR?
its freely filtered at the glomerulus and not reabsorbed, secreted or metabolised
how much blood actually gets filtered?
125ml and the rest flows through the efferent arteriole
What is the filtration fraction?
GFR/RPF
filtered load?
Amount of a particular substance filtered per minute
filtration load equation?
GFR* solute plasma conc
the glomerular filtration rate (GFR) is defined?
1- amount of substance filtered per time
2- volume of urine produced per day
3- amount of water both kidneys reabsorb per day
4- volume of plasma filtered per time
5- amount of sodium filtered per time
4
what is the main driving pressure?
blood pressure
osmotic pressure is the main opposing force
facts
what does clearance measure?
can measure the plasma
water reabsorption is based on what
Na
how much is plasma filtered?
60 times over
what is osmolarity based on?
Number of osmotically active ions or solutes
e.g. 145mM NaCl has an osmolarity of 290mosmol/L
Can be estimated by specific gravity (density of solutions)
the ECF ?
1- has a normally higher osmolarity compared to the ICF
2- Shows a sodium concentration of the 145mM
3- has normally a higher tonicity than the cells
4- stores 2/3 of the total body water (TBW)
5- is mostly affected by sweating
2
How much Na is reabsorbed in the PCT?
67%
How much Na is reabsorbed in the TAL?
25%
How much Na is reabsorbed in the DCT?
5%
How much Na is reabsorbed in the CD?
3%
what is used to reabsorb glucose?
sodium glucose co-transporter
water reabsorption in the kidneys is 1- mainly facilitated by the TAL 2- facilitated by potassium reabsorption 3- independent of sodium reabsorption 4- facilitated by glucose reabsorption 5- facilitated by sodium secretion
4
what makes up the obligatory water reabsorption ?
first half of the loop
92%of the total water reabsorption
what makes up the facultative water reabsorption?
the right side of the nephron
a change in the water content causes ??
a change in osmolarity
what does total body weight alter?
plasma osmolarity
this gets detected by the brain and then sends a hormone ADH so water balance can change in the collecting duct
what does ADH do ?
Facilitates reabsorption of water in the nephron of the kidney by producing aquaporins in the surface of the plasma membranes
anti diuresis
has ADH
diuresis
has no ADH
the urine osmolarity is 1- high without ADH 2- independant of plasma osmolarity 3- controlled by the pituitary gland 4- independent of ADH 5- high in diuresis
3
what do the densa cells sense?
changes in sodium reaching the DCT and when it is too low it leads to a release of renin from the jux
