Urinary System Flashcards
Urinary System
composed of 2 kidneys, 2 ureters, one bladder, and one urethra
each ureter drains from the kidneys to the urinary bladder wehre wasted is carried from the urethra to exit the body
kidneys
- bean-shaped organ that is about 5 oz. (size of a soup can)
- right kidney is slighly lower due to the liver aboce it
- both are protected by the rib cage btw T-12 & L-3
function: maintain homeostais of the bodys fluid, blood volume and chemical composition, as well as filter waste
is a cleft in the medial convcave surface of the kidneys that lead to the renal sinus
renal hilus
where the ureters, blood vessels and nerves are, which enter the kidney at the hilus
renal sinus
inner protective layer of the kidney that has a tough fibrous outer skin to protect it from injury and infection
renal capsule
is a fatty protective layer that protects the kidney from trauma outside the renal capsule
adipose capsule
a dense fibrous connective tissue that keeps the kidney in place within the abdominal cavity
renal fascia
is a continous outer region with several projections inside the renal capsule
renal cortex
several projections that extend down btw the renal medulla pyramids
cortical columns
extensions of the pelvis that collect urine and drains it into the renal pelvis
calyces
are divided sections that point toward the center of the kidney in the renal medulla
renal pyramids
What is the centermost section of the kidney near the renal hilis that forms a funnel-shaped tube?
renal pelvis
it connects to the ureters when leaving hilus
What transports urine from the kidneys to the bladder to be stored by these thin muscular tubes
Ureters
- where the kidney and nervous system interact here
- its fibers follow the renal arteries to reach the kidney
renal plexus
where are the sphincters located when the ureters enter bladder?
ureterovesical valves
the downward flow of urine through here helps to prevent back flow of urine to the kidneys
is a hollow, muscular, elastic pouch that revives and stores urine exreted by the kidneys before disposal through the urethra
bladder
What’s the different btw male and female bladder
male bladder is located at the base of the rectum and behind the pubic symphysis
female bladder is located below the uterus and in front of the vagina
the max capacity of the bladder is lower than males b/c there are more organs
are where the ureters open into the bladder
ureteral orifices
smooth, triangular center region of the bladder
trigone
is the middle muscular layer of the bladder that contains inner and outer longitudinal layers
detrusor muscle
specialized cells that enable cellular expansion in order to absorb fluid
this makes up the inner mucosal layer of the bladder wall
transitional epithelium
What are the folds in the bladder wall that extend to help internal bladder capacity?
Rugae
what is the release of urine from the bladder through the urethra and urethral orifices
micturition
- is the amount of pressure inside the blood of the capillaries which drives fluid out of them
- varies from person to person depending on BP from their heart and vessels
- it has a direct relationship with BP (when one increases, the other increases)
blood hydrostatic pressure
What is the measurement in which all fluid pressures in glomerular fliltration are recorded?
mmHg (milimeters of mercury)
This depends on the amount of proteins in the blood and opposes hydrostatic pressure by driving fluids back into capillary beds to draw water out of fitrate?
also known as oncotic pressure
colloid osmotic pressure (COP)
What is the mechanical pressure exerted by recoil of the elasticiy inside the glomerular arterioles that also opposes blood HP and drives fluid back into the glomerular capillaries?
capsular hydrostatic pressure
What is the difference in pressure btw ougoing and incoming forces at the glomerulus?
Net filtration pressure (NFP)
what is the flow of blood through the vessels of the kidney?
Renal artery Segmental artery (5) Lobar artery Interlobar artery Arcuate artery Interlobular artery Afferent arteriole Glomerular capillaries Efferent arteriole Peritubular or vasa recta capillaries Interlobular vein Arcuate vein Interlobar vein Renal vein
How much can the bladder hold?
500 ml, and 1000ml if completely necessary
what is the tube from bladder to exterior and has
sphincters to the control exit of urine
the ureters
What has a normal range btw 25 - 32 mmHg
Colloid osmotic pressure (COP)
what is the functional and structural unit of a kidney?
A nephron
How many times does the kidneys filter the blood plasma volume each day?
60 times
also uses about 25% of the body’s resting energy to excrete wastes
How much glomerular filtrate is removed daily?
About 47 gallons containing water, nutrients, and essential ions are removed daily
by the time filtrate enters the collecting ducts, it contains only about 0.5 gallonsof urine
what are the 3 processes essential for filtering the blood?
Filtration, Reabsorbtion and Secretion
What is urochrome?
It is a pigmented blood product that gives the yellow color of urine
What are solutes are found in the urine?
Na+, K+, HCO3-, Urea, Uric acid, creatinine, NH3, etc
What are solutes are NOT found in the urine?
glucose, blood, proteins, RBCs, hemoglobin, WBCs (pus), bile
Why do the kidneys have a rich blood supply?
they continuously cleanse the blood and adjust its composition
What are the two main structures of a nephron?
The renal tubule and the glomerulus
What prevents the passage of blood from exiting the capillaries?
The size of the capillary fenestrations, which also prevents most of the blood proteins from exiting as well
What does a three regions of the inner kidney are shown in a vertical cross section ?
The renal pelvis, renal cortex and medulla.
What adjusts the diameter of the renal arteries thereby regulating renal blood flow. ?
in put from the sympathetic nervous system
What is the amount of blood filtered by the glomerulus over time called?
the glomerular filtration rate
What is the normal GFR rate?
120-125 ml/min or 180L/day due to large surface area of glomerular caillaires
What causes the GFR to increase?
An increase in the arteriral/glomerular blood pressure in the kidneys
What causes the GFR to decrease?
An increase in glomerular osmotic pressure due to dehydration
Why is it important to maintaina constant GFR?
to allow adequate reabsoprtion of water and other needed substances from the filtrate and filtration of wates
What happens if the GFR flow is too slow?
`nearly all the filtrate is reabsorbed, which includes most of the wastes that should be excreted
What happens if the GFR flow is too fast?
Needed substances cannot be adequately reabsorbed
What are the 3 mechanisms that regulate renal blood and GFR?
renal autoregulation, nervous system control, and hormone control
what is the mechanism in which the kidney controls its own rate of blood flow by controlling the diameter of afferent and eferent arterioles?
renal autoregulation
What mechanism occurs in an emmergency to divert blood away from kidnyes to vital organs (brain, heart, skeletal muscles)?
nervous system control
What happens when nervous system control takes over?
It supersedes renal autoregulation, and causes the afferent arterioles to narrow in diameter caused by the sympathetic nerv fibers
What hormone is released by the adrenal medulla in the adrenal glands?
Epinephrine
What does the release of epinephrine do?
It causes a decrease in the renal blood flow and decreases the glomerular filtration rate (GFR)
What would happen if the nervoys system constricted lood flow to the kidneys for a long time?
Damage to the kidneys may occur b/c of the decreased blood supply to the kidney’s cells
what is the hormonal mechanism that controls renal flow and GFR called?
The renin-angiotensin-aldosterone (RAA) system?
what are the 3 layers of the ureter walls
- outer adventitia - fibrous connective tissue
- middle muscular layer: 1 longitudinal and 1 circular
- inner lining - transitional epithelium and is continuous with the kidney’s linings.
When does the RAA system respond?
When the body’s blood pressure drops too low
Is a pre-enzyme that is produced by the liver and freely circulates in the blod
angiotensinogen
this enzyme is released by the juxtaglomerular cells of the nephron when blood pressure drops and causes the afferent and efferent arterioles to constrict
renin
what does renin convert angiotensinogen to?
angiotensin 1
What do the lungs convert angiotensin 1 into?
Angiotensin 2
what triggers the thirst mechanism of the hypothalamus to cause someone to feel thristy
angiotensin 2
TRUE/FALSE: Drinking water helps to increase blood volume and therefore blood pressure.
True
what causes vasoconstriction to increase blood pressure
angiotensin 2
is a hormone released after angiotensin 2 reaches the adrenal cortex
aldosterone
what causes the renal tubules in the neprhon to reabsorb more sodium ions (and water in as a result?)
aldosterone
what helps in the reabsoption of more water and sodium from filtrate?
The RAA system (The Renin-Angiotensin-Aldosterone System)
what is the normal blood pH?
4.5 - 8.0
what is the process of fluid an substances moving from filtrate back into blood?
reabsorption
what happens if rebsportion didn’t occur?
the blood plasma would be filtered wth it –> death
this is a passive process that doesn’t need energy
diffusion
where do the greatest amount of renal tubular reabsoprtion take place?
the proximal convulted tubules (PCT)
ths includes Na+, HCO3- (bicarbonate), water, Cl- (chloride) K+ and some Calcium, phosphate and magnesium
All the glucose and amino acids are actively reabsorbed here in addition to most of the water and other ions
PCT
True/False: reabsoprtion characteristics of the descending and ascenidn glimbs of the loop of Henle act in different ways from each other
True
what can leave the descening limb but not the ascending limb?
water
what can leave the ascending limb but not the descending limb?
sodium and potassium
what are the three types of capillaries associated with nephrons?
the glomerular capillaries, peritubular capillaries and the vasa recta.
functions to remove toxins, maintain water volume homeostasis, and blood pressure
the urinary system
what are the 3 regions of the male urethra?
- the prostatic urethra which runs through the prostate gland
- membranous urethra whch uruns through urogenital diaphragm
- spongy (penile) urethra which runs within penis and oens external ureteral opening
what is located near the bladder, involuntarily controlled and keeps the urethra closed to prevent urine from leaving
the internal urethral sphincter
what is voluntarily-controlled, made of skeletal muscle and surrounds the urethra as it passes the pelvic floor
the external urethral sphincter
What is a problem that some females face with having shorter urethra’s?
females are at risk of getting a UTI (Urinary tract infection) with poor hygien, fecal bacteria can enter the uruetha since the urethra is near the anus
what helps to eliminate waste, regulate blood volume, pH, pressure and control electrolyte levels?
nephrons
What does each nephron have?
a glomerular capsule (Renal corpuscle) and a renal tubule that are connected by associated collecting ducts
what 3 parts make up the renal tubule?
the Proximal convuluted tubule, loop of Henle, and the distal convuluted tubule
Is a network of blood capillaries that are extremely porous and filter the blood?
glomerulus
Is a double-walled cup of simple squamous epithieum of the glomerulus
The glomerulus (Bowman’s) capsule
what reabsorbs needed materials in the kidney?
the renal tubule
what carry the reaining material away as urine to be excreted?
collecting ducts
What is made of the glomerulus thats surrounded by the glomerular (Bowman’s) capsule?
renal corpuscle
What is fed by the interlobular artery and is much larger in diameter?
afferent arteriole
What causes an extremely high blood pressure in the glomerular capillaries, forcing water and solutes out of the blood, thus making filtration possible?
The difference in diameter of the afferent and efferent arterioles
Becomes this once water and solutes leave the blood and enter the glomerular capsule
Filtrate
What make up 85% of the kidney’s nephrons and are found in the cortex region of the kidney that extend into the medulla?
Cortical nephrons
Nephrons that pass deeply into the medulla
juxtamedullary nephrons
What is specialized to reabsorb water and many solutes from the glomerular filtrate into the low-pressure peritubular capillaries that surround the renal tubule as well as secrete certain unwanted substances?
PCT
What part of the Loop of Henle allows water loss?
The descending limb
What part of the Loop of Henle allows salt loss?
The ascending limb
what is highly coiled, allows for hormonally controlled reabsorption of water and solutes, and mostly responsible for secretion of uneeded substances?
DCT
when does filtrate turn into urine?
when it reaches the renal pelvis
Collecting ducts converge to make these, which drain into calyces and then renal
papillary ducts
These are highly coiled capillary beds formed from the afferent arteriole, leaving as the efferent arteriole
glomerular capillaries (glomerulus)
What closely follow the renal tubules and drain into the interlobular vein?
Peritubular capillaries
what are adapted for absorption, reclaming water and solutes from filtrate due to their low pressure and porosity?
Peritubular capillaries
are capillaries that follow the loop of Henle in the juxtamedullary nephrons of medulla
vasa recta
What is the inability to voluntarily control micturition?
Incontinence
what is the inability to expel stored urine?
urinary retention
Steps of Micturition?
- rugae (folds in bladder wall) thin and stretch to expand and store greater amounts of urine w/o increasing pressure
- after 200ml of urine being accumulated, the urge begins causing the walls to distend and a visceral reflex arch to react
- detrusor muscle contracts and the internal sphincter relaxes –> forcing urine through uppper part of urethra
- after, person has consciousness to resist urge due to voluntary external sphincter
what is the normal range of COP?
25-32 mmHg
what is NFP?
Outgoing forces (Hydrostatic pressure) - incoming forces (COP + Capsular Pressure)
What is a mechanical pressure that is exercised by the recoil of the elasticity within the glomerular arteries. This pressure also opposes hydrostatic pressure and drives fluid back into the capillaries.
Capsular pressure
About what percentage of Na+ is reabsorbed in the PCT? The loop of Henle? The DCT?
About 65% of Na+ is reabsorbed in the PCT
25% of Na+ n the loop of Henle
and 10% reabsorbed in the DCT (reclaims nearly all when necessary)
Is the process in which substances enter the filtrate from surrounding fluids to excrete undesirable substances (urea, drugs, excess K+ ions)
Secretion
describes the movement of fluids in opposite directs
filtrate flows in one direction through renal tubules, while blood flows in the opposite direction
countercurrent flow
when the solute outside a membrane is equivalent in concentration and pressure to the solute within a membrane. This is found in the PCT.
isosmotic
What is the concentration of the filtrate in the PCT vs. the bottom of the loop of Henle?
The filtrate concentration in the PCT is 300 mOsm/L versus 1200 mOsm/L in the bottom of the loop of Henle.
ADH is produced by what secreted by what?
produced by hypothalamus and secreted by the posterior pituitary gland
True/False: ADH increases water output.
False
what inhibits urine output by increasing the number of channels in the collecting ducts’ cells to allow water to pass easily from filtrate into interstitial space?
ADH (antidiuretic hormone)
is a hormone that is released by the adrenal cortex by the RAA system tha places several types of ion channels within the collecting ducts’ cells of the kidney.
Aldosterone
substances that act on the nephron in order to increase urinary output.
diuretics
are in the aorta and carotid arteries by control of the vagus and glossopharangeal nerves
inhibit sympathetic nervoys system signals to kidney if blood volume and BP rises
dilate afferent arterioles and dramatically increases filtration rate to increase output of water and Salt to reduce blood volume
cardiovascular barocreceptors
What is found primarily in the intracellular and extracellular fluids inside cells of the body?
water
what is the noram GFR?
120-125ml/min or 180L per day
when BP drops, renin is realeased by which cells of the nephron?
juxtoglomerular cells (next to glomerulus)
is a result of when blood pH levels start to drop and become more acidic
causes the respiratory center to become excited and remove addition CO2
used by respiratory control mechanism
Hyperventilation
if blood pH starts to rise and become more basic/alkaline
respiratory system becomes depressed and accumulates more CO2
used by respiratory control mechanism
this happens
Hypoventilation
How does the respiratory center control pH?
chemoreceptors in the medulla (of brainstem) monitor CO2 in the blood
Bicarbonate is the form in which CO2 is transported in blood plasma
Occurs when too much alkaline is in the blood, pH rises higher than 7.8, CNS becomes too excited, extreme nervouseness, covultions and even cessation of breath
alkalosis
occurs when too much acid is in the blood, pH drops below 7.0, CNS becomes too depressed; no intervention can cause coma or death
acidosis
whats the normal blood serum level for HCO3-?
22-26 mEq/L.
What’s normal blood serum level for PCO2?
35-45 mmHg
What’s the process in which some substances present in peritubular capillaries must be removed by?
Tubular secretion
Is a substance converted from ammonia to be excreted as urine
urea
is the principal pigment of urine determined from the metabolic breakdown of hemoglobin
urochrome
is the fluid inside the cells, accounting fro 60% of fluid in body
ICF
is the fluid outside the cells, accounting for 40% of fluid in body
ECF
found in the microscopic spaces btw cells - about 12 L
Interstitial fluid
passive process that doesn’t require energy
Diffusion
secretion of HCO3- (bicarbonate) and H+ (hydrogen ions) controls what?
blood pH
refers to the concentration of solutes inside a solution, measured in milliosmoles/liters (mOsm/L)
Osmotic gradient
channel caused by aldosterone that increases Na+ reabsoption by excreting H+, which causes water reabsorption
sodium-hydrogen ion channel
Action of aldosterone that increases K+secretion, Na+ is pumped out to return to blood and K+ is excreted in urine –> this increases Blood volume and BP when needed
sodium-potassium pumps
(chemical reactions inside a cell to maintain life) is the principal method through which acids enter the human body.
cellular metabolism
is a negatively charged ion, for example the bicarbonate ion (HCO3-)
anion
is a positively charged ion, such as ammonium (NH4+).
cation
acts as the main buffer of the interstitial and plasma fluids
bicarbonate system
acts as a buffer in urine and ICF
phosphate system
acts as a main buffer of ICF that has the largest buffering capacity
protein system
CO2 reacts reversibly with water to form?
carbonic acid (H2CO3)
carbonic acid dissociates when dissolved in water to form H+ and what?
bicarbonate ions (HCO3-)
is the form in whcih CO2 is transported in the blood plasma
