Urinary system Flashcards
The urinary system consists of what 6 organs ?
Kidneys(2, Ureters (2), urinary bladder, and urethra
True or false the Right kidney is slightly lower than left due to space occupied by liver
True
What does it mean to say that the kidney is retroperitoneal?
It lies between the peritoneum and body wall at the level of T12-L3
What 8 things do the kidneys do?
1 Filter blood plasma (eliminates waste), regulates blood volume and pressure, regulates osmolarity of body fluids , Secretes Renin(activates angiotension and aldosterone), secretes erythropoietin(controls RBC count), regulates acid and base balance, detoxifies free radicals and drugs, and glucogenisis.
What are the 5 nitrogenous wastes?
Urea, uric acid, creatine, renal failure, and BUN
Define BUN
quantitative expression of blood nitrogenous waste products
Define azotemia
abnormally elevated BUN in blood that may indicate renal insufficiency
Define uremia
toxic effects as wastes accumulate
Define excretion
Separation of wastes from body fluids and eliminating them using four organ systems
What are the four organ systems the body uses to excrete waste? What do they excrete?
Respiratory System: CO2,
Integumentary system: water, salts, lactic acid, urea, and sweat
Digestivesystem: water, salts, CO2, lipids, bile pigments, cholesterol
Urinarysystem: many metabolic wastes, toxins, drugs, hormones, salts, H+and water
True or false the kidneys are about the size of a bar of soap
True
Define Hilum
slit where it receives the renal artery, vein, ureter and lymphatic vessels
True or false the kidney is protected by three layers of C.T
True
What is the outer most layer of the kidney ?
Renal fascia-binds the kidney and associated organs to the abdominal wall
What is the middle protective layer of the kidney?
Adipose tissue , layer of fat that holds kidney in place.
What is the inner most protective layer of the kidney ?
Renal capsule-a fibrous sac that is anchored at the hilum and encloses the rest of the kidney like a cellophane wrapper, and protects it from trauma and infection
What is the Renal parenchyma and what two zones is it divided into?
Its the glandular tissue that forms the urine, appears C shaped and encircles the renal sinus . It is divided into the renal cortex and inner medulla
What does the renal sinus contain?
containing blood vessels, nerves, and urine collecting structures
_______ divides the medulla into 6-10 renal pyramids
Renal columns
Each pyramid is conical with a broad base facing the cortex and a blunt point called _______
Renal papilla
One pyramid and the cortex above it constitute a ____
Lobe
Starting with a minor calyx how does urine make its way to the ureter?
Each renal pyramid releases its urine to a minor calyx which converges with others(2 or 3) to create a major calyx which converges (2 or 3 ) into a funnel like Renal pelvis which connects to a ureter
True or false the kidneys receive 21% of the cardiac output
True
True or false each kidney is supplied by a renal artery
True
Renal arteries enter the hilum and divide to ____ arteries
segmental
Segmental arteries divide into ___ arteries which penetrate each renal column.
interlobar
interlobar arteries travel up to the cortico-medullary junction where they form ___ arteries
arcuate
What kind of arteries branch upward into the cortex coming off of the arcuate areries?
interlobular
What kind of artery gives off afferent arterioles to the gomerulus of each nephron?
interlobar
True or false The glomerulus is drained by an efferent arteriole
True
True or false Each kidney contains 1.2 million functional units called nephrons
True
A nephron consist of what two principal parts? What are their functions?
Renal corpuscle-(glomerulus) where the blood plasma is filtered
Renal tubule-processes the filtrate into urine
What is the glomerulus?
a ball of capillaries
What is the glomerular (Bowmans)capsule?
A two layered capsule . The parietal layer is simple squamous and the visceral consists of podocytes wrapped around the capillaries.
Define glomerular filtrate and capsular space
fluid that filters from the glomerular capillaries collects in the capsular space between the parietal and visceral layer and then flows into the renal tubule.
Define Renal (Uriniferous) Tubule
a duct (divided into 4 regions) that leads away form the glomerular capsule and ends at the tip of a medullary pyramid
Name the four majore regions of the Renal tubule
Proximal convoluted tubule
Nephron loop(loop of Henle)
Distal convoluted tubule
Collecting duct(not really a part of the nephron-receives urine from many nephrons
True or false the PCT is the longest and most coiled and has simple cuboidal epithelium with microvilli
True
Thin segments are made if simple squamous have low metabolic rate but are very ____ to water
permeable
Thick segments have simple cuboidal with lots of mitochondria due to high metabolic activity of ___ _____.
Active transport
True or false the DCT is less coiled than the PCT
True and SCT has cubiodal epithelium
True or false both the DCT and the collecting duct are made of cuboidal epithelium
True
What does the juxtaglomerular apparatus consist of?
DCT, afferent, efferent arterioles
True or false the collecting duct has several DCT’s that join it
True
True or False Near the papilla, several collecting ducts merge to form a larger papillary duct where they converge more to become a minor calyx
True
Define cortical nephrons
(85%) nephrons close to the kidney surface
Define Juxtamedullary nephron
-(15%) nephrons close to the medulla
what nephrons Have very long loops that extend to the apex of the renal pyramid
Juxtamedullary
True or false Juxtamedullary Responsible for maintaining the salinity gradient
True
The kidney converts blood plasma to urine in what three stages
Glomerular filtration
Tubular reabsorption and secretion
Water conservation
True or false Glomerular filtrate is fluid in the capsular space that is similar to blood plasma except that it has almost no protein
True
Define tubular fluid
fluid from the PCT through the DCT
When is fluid officially called urine?
When they exit DCT and enter the collecting ducts
Define the filtration membrane
barrier through which the fluid must pass to enter the capsular space
What three things compose the filtration membrane?Deep to superficial
fenestrated endothelium of the capillary, The basement membrane and, Filtration slits.
True or False Pedicles have a negatively charged filtration slits
True
Where exactly does filtration take place?
glomerulus
True or false
Kidney trauma and infections can damage the filtration membrane and allow albumin or blood cells to filter through
Define Proteinuria(albuminuria)
the presence of protein in the urine
Define Hematuria
the presence of blood in the urine
What can cause an temporarily cause proteinuria or hematuria
Strenuous exercise
Define Nephrotic syndrome
A group of symptoms caused by excessive loss of protein in the urine(Hypoalbuminemia, hypercholesterolemia,edema)
What are the two types of hematuria?
Microscopic- amount of blood so small that it can only be seen under a microscope.
Gross/macroscopic- Urine is pink or red and may contain some blood clots
Define pseudohematuria
Excessive consumption of beets, berries, or rhubarb; food coloring; and certain laxatives and pain medications can produce pink or reddish urine.
True or false the blood hydrostatic pressure is much higher in the glomerulus than most other capillaries
True, the afferent arteriole is substantially larger than the efferent arteriole, giving the glomerulus a large inlet and small outlet
True or false The glomerular filtrate is almost protein-free and has no significant COP (colloid osmotic pressure)
True
Define Glomerular filtration rate GFR
the amount of filtrate formed per minute by the two kidneys combined
True or false 99% of the filtrate is reabsorbed and approx. 1-2 L of urine are excreted per day
True
What can happen if the GFR is too high?
Fluid flows to fast for them to reabsorb the usual amounts of water and solutes .
Urine output rises and creates a threat of dehydration and electrolyte depletion
What can happen if the GFR is too low?
Fluid flows sluggishly through the tubules and they reabsorb wastes that should be eliminated and azotemiamay occur
What 3 ways can GFR be adjusted by adjusting glomerular blood pressure?
- Renal auto-regulation
- Sympathetic control
- Hormonal control
Define Renal-Autoregulation
ability of the nephrons to adjust their own blood flow and GFR without external (nervous or hormonal) control.
What are the two mechanisms of auto regulation?
Myogenic mechanism and Tubuloglomerular feedback
How does the myogenic mechanism work to keep GFR constant ?
afferent arteriolar vasoconstrictionwould serve to protect the glomerulus from uncontrolled systemic hypertension
while afferent arteriolar vasodilatationwould allow for greater blood flow into the glomerulus in times of hypotension
The juxtaglomerular apparatus is made up of specialized cells in the walls of afferent, efferent, and DCT. The cells make up the ______ _____
Macula Densa
True or false the Juxtaglomerular apparatus is innervated byadrenergic fibersand the granular cells carry renin in intracellular granules
True
Define the tubuloglomerular feedback (TGF) loop
JGA adapts to the GFR to early distal tubule fluid by modulating renin synthesis and release
renin release is pricipally controlled by what 3 things
altered sodium concentration at the macula densa of the distal tubule
changes in the blood flow patterns of the afferent arteriole
adrenergic stimulation
True or false When blood pressure drops, the sympathetic nerves stimulate the JGA cells to secrete renin
True
Renin acts on angiotinsinogen to create _______
angiotensin I
Angiotensin I is converted to angiotensin II by the action of angiotensin-converting enzyme (ACE) from the ____
Lungs
Treu or false Renin-Angiotensin Mechanism Stimulates the adrenal cortex to secrete aldosterone, which in turn promotes sodium and water retention
True
True or false Renin-Angiotensin Mechanism Stimulates the sense of thirst and encourages water intake
True
Angiotensn II release is dependent on____release
renin
Sympathetics can ______urine production, redirecting blood flow to heart, brain and skeletal muscles
decrease
Tubular reabsorption removes useful solutes and returns them to the ___ and tubular secretion removes waste from the blood and adds them to the ______.
Blood, Filtrate
True or false PCT reabsorbs greater variety of chemicals than other parts of the nephron and use 6% of resting ATP and calories
True
What are the two routes PCTS reabsorb chemicals?
Transcellular (through epithelial cells of PCT) paracellular route (between epithelial cells of PCT)
What creates the osmotic and electrical gradient ?
sodium
Whats the primary function of the nephron loop ?
water conservation, also involved in electrolyte re-absorption
DCT and collecting ducts Controls fluid and sodium/potassium balance because cells are subject to _____ control
Hromonal control , (esp. aldosterone, atrial natriuretic peptide, ADH, and parathyroid hormone)
DCT and collecting ducts have what two kinds of cells?What are they involved in?
Principle cells(most abundant ) have receptors for hormones and are involved chiefly in salt and water balance Intercalated cells: reabsorb K+ into the tubule lumen and involved mainly in acid-base balance
How does atrial natiuretic factor (ANF) lower BP?
↑BP stimulates right atrium
atrium secretes ANF
ANF promotes Na+and water excretion
BP drops
How does ADH help raise BP?
dehydration stimulates hypothalamus
hypothalamus stimulates posterior pituitary
posterior pituitary releases ADHADH ↑water reabsorption
urine volume ↓
True or false Osmolarity 4x as high deep in medulla
True
True or false Medullary portion of Collecting duct is permeable to water but not to NaCl
True
The Kidney Has an Osmotic Gradient From _____ to _____.
Cortex to medulla
The countercurrent mechanism is based upon the ___ pump
Na , sodium is pumped out into the interstitial fluid in medulla
The concentration of the urine is adjusted in the ____ of the kidney
collecting ducts
Because there is such a high concentration of sodium in the medulla of they kidney Water will be sucked out of the tubules by osmosis if the tubules are _____.
permeable
The permeability of the collecting duct is determined by water pores(aquaporin-2) which are under the control of ______________________ from the posterior pituitary
antidiuretic hormone(ADH-also called vasopressin)
If ADH is high the kidney makes _____ urine and conserves water
concentrated
When a person is dehydrated the blood osmotic pressure_____.
rises
The ADH will cause the kidney collecting ducts to insert ______ pores.
Water pores
Define Diabetes insipidus
is the continuous production of large amounts of watery urine(5-10 L/day
Aldosterone acts by turning on genes (transcription), so its stimulation of Na retention is relatively ___.
slow
___ causes production of NA pump molecules
Aldosterone, secreated by adrenal gland in response to lowerd blood pressure.
True or false Parathyroid Hormone Effects the Kidney by promoting calcium reabsorption and Stimulates the kidney to complete the synthesis of calcitriol (Vit. D)
True
Define diuretic
causing increased passing of urine.
caffeine and alcohol are ____
Diuretics
Diabetes Mellitus-_______ urine reabsorption
decrease
Define Urinalysis
The examination of the physical and chemical properties of urine
What do abnormal pee colors mean?
red urine can be caused by red blood cells or hemoglobin in the urine or by the red pigments found in beets
beer-brown or yellow-brown urine is most often seen when bilirubin is present
black urine occurs when melanin is found in the specimen
orange, blue and green are often associated with the presence of drug, dye or food metabolites.
What does cloudy urine probably mean?
upon standing can develop bacteria growth
Define Pyuria
-pus in the urine, suggesting infection
Define Specific gravity
the ratio of the density of a substance to the density of distilled water
what are the two primary reasons why the kidney produces concentrated urine with a high specific gravity.
Dehydration and increased secretion of anti-diuretic hormone (ADH). can occur because of trauma, stress reactions, and surgery
Define oliguria
the production of abnormally small amounts of urine.
Define Azotemia
-A higher than normal blood level of urea or other nitrogen containing compounds in the blood due to low urine output
What are the three layers of the ureters?
adventitia –connective tissue
muscularis -2 layers of smooth muscle,Urine stretches tube causing the muscularis to contract in paristaltic waves, milking urine down to the bladder
mucosa -transitional epithelium
Explain the Micturition reflex
urine in bladder, stretch receptors send signal to spinal cord, parasympathetic reflex arc from spinal cord, stimulates contraction of detrusor muscle,relaxation of internal urethral sphincter.
The hypogastric nerve sympathetically surpresses ____________________________________________
contractions of the detrusor muscle and relaxation of the internal sphincter
The pelvic nerve parasympathetically ________
cause the detrusor to contract and relaxation of the internal sphincter.
The external sphincter is innervated by what nerve?
puendal
