wendy_reddyPLUS
Terms in this set (151)
What does the Urinary System consist of?
-kidneys
-ureters
-bladder
-urethra
-associated nerves and blood vessels
In what ways does the Urinary System maintain homeostasis?
-regulating blood volume, blood pressure, pH, and concentration (osmolarity) of electrolytes (Na+, K+, Ca2+, Cl-, HPO4-3, Mg2+, HCO3-)
-reabsorbing glucose and excreting wastes
-releasing certain hormones like renin and EPO
What shape are the kidneys? Where are they located?
-bean shaped
-just above the waist between the peritoneum and the posterior wall of the abdomen (in the retroperitoneal space)
What are the three layers of tissue surrounding the kidney from deep to superficial?
1. renal capsule (deep layer)
2. adipose capsule (middle layer)
3. renal fascia (superficial layer)
Which ribs are the kidneys protected by?
-eleventh and twelfth pair of ribs
Because of the position of the liver, which kidney is positioned slightly lower?
-the right
A ureter is approximately how long?
-25cm (9.84 almost 10 inches)
A ureter originates near an indented area of each kidney called the _________________ and travels to the base of bladder.
-hilum
In addition to the ureter, what else emerges from the hilum?
-renal blood vessels
From the bladder, what structure allows urine to be excreted? what is the length of this structure in males and in females?
-males: 24cm (9.44 in)
-females: 4 cm (1.5 in)
If one takes a frontal section through the kidneys, it will reveal two distinct regions of internal anatomy. What are these two distinct regions?
1. renal cortex
2. renal medulla
What is the main function of the renal cortex?
-filtration to form urine
What is the main function of the renal medulla?
-collect and excrete urine
The renal medulla consists of several cone shaped what?
-renal pyramids
The renal pyramids consist of how many conical subdivisions within the medulla?
-8 to 18
The subdivisions in the renal pyramids within the medulla contain what?
-the kidney's secreting apparatus and tubules
________________ are composed of lines of blood vessels and fibrous material which allow the cortex to be better anchored.
-renal columns
What is the location where the medullary pyramids empty urine into cuplike structures called minor and major calyces?
-renal papilla
How many minor calyces are there? How many major calyces are there?
-2 to 3
What is it that receives urine from the papilla of one renal pyramid?
-minor and major calyces
Once the filtrate enters the calyces, what does it become? And why?
-urine
-because no further reabsorption can occur
Once urine goes through the minor calyces and into the major calyces, it then drains into a single large cavity called what?
-renal pelvis (then it goes out through the ureter)
The hilum expands into a cavity within the kidney called the __________________, which contains part of the renal pelvis, the calyces, and branches of the renal blood vessels and nerves.
-renal sinus
The ureter transport urine from the renal pelvis of the kidneys to the bladder, using what three things to move the urine?
-peristaltic waves
-hydrostatic pressure
-gravity
Note: there is no anatomical _____________ at the opening of the ureter into the bladder.
-valve
The urinary bladder is a hollow, distensible, and muscular organ with a capacity that averages _____________.
-700 to 800 mL
The act of emptying the bladder is called _______________ or urination and requires a combination of voluntary and involuntary muscle contractions.
-micturition
When volume of the bladder increases, stretch receptors send signals to a micturition center in the spinal cord triggering a spinal reflex called the ______________ reflex.
-micturition reflex
(note: in early childhood we learn to initiate and stop the reflex voluntarily)
The urethra is a small tube leading from the _____________________ in the bladder floor to the exterior.
-internal urethral orifice (picture of woman)
The urethra is a small tube leading from the internal urethral orifice in the bladder floor to the exterior. In males, what is the urethra used for in addition to urination?
-discharge of semen
The renal artery and renal vein pass into the substance of the kidney at the hilum. Arterial blood enters via the renal artery and exits the renal vein. The renal arteries are very large branches of the aorta, and up to how much of total cardiac output can pass through them to be filtered by the kidneys.
-a third
What is the functional portion of the kidney called?
-the parenchyma
List the path that blood follows through the kidney. It consists of 11 steps.
1. Renal arteries
2. Segmental arteries
3. Interlobar arteries
4. Arcuate arteries
5. Interlobular arteries
6. Afferent arterioles
7. Glomerular capillaries
8. Efferent arterioles
9. Peritubular capillaries
10. Intertobular arteries
11. Arcuate Veins
12. Interlobar veins
13. Segmental veins
14. Renal veins
What is the functional unit of the kidney?
-the nephron
The nephron is a microscopic structure composed of ______________ and ______________ that collect filtrate which ultimately become urine.
-blood vessels
-tubules
What is the structures difference between afferent and efferent arterioles?
-afferent arterioles are big and wide
-efferent arterioles are super tiny and small
What is one common thing that is extremely necessary for kidney function?
-blood pressure (No BP no PP)
Each nephron receives one afferent arteriole which divides into a tangled ball-shaped capillary network called the what?
-glomerulus
In the nephron, the glomerular capillaries then reunite to form what? This is what carries blood out of the glomerulus.
-efferent arteriole
The glomerulus is a small tuft capillaries containing two cell types. What two types of cells are these?
1. endothelial cells (large fenestrae)
2. Mesangial cells (modified smooth muscle cells that lie between capillaries and glomerulus)
The Bowman's capsule has an outer parietal layer composed of simple squamous epithelium and a visceral layer composed of modified simple squamous epithelium cells called _______________.
-podocytes
Podocytes have foot processes and pedicels that wrap around glomerular capillaries. These pedicels interdigitate with pedicels of adjacent podocytes forming what?
-filtration slits
Podocytes are also called what? They are cells of the visceral epithelium in the kidneys and form a crucial component of the glomerular filtration barrier, contributing size selectively and maintaining a massive filtration surface.
-visceral epithelial cells
Fluid filtered from the glomerular capillaries enters what?
-Bowman's Space (the space between two layers of capsule) which is the lumen of the urinary tube.
Blood plasma is filtered through the glomerular capillaries into the glomerular capsule (bowman's capsule). Filtered fluid passes into the ______________, which has three main sections. What are these sections?
-renal tubule (note: remember blood plasma is filtered but the formed elements like red and white blood cells have to stay in because they're too big).
1. proximal convoluted tubule (PCT)
2. the loop of henle
3. distal convoluted tubule (DCT)
The distal convoluted tubules of several nephrons empty into a single _________________.
collecting duct
Collecting ducts unite and converge into several hundred large ___________________, which drain into what?
-papillary ducts
-minor calyces, major calyces, renal pelvis, and ureters
How many minor calyces are there?
The first part of the loop of henle, the ________________, dips into the renal medulla. It then makes a hairpin turn and returns to the renal cortex as the ______________.
-descending limb
-ascending limb
The descending limb of the loop of Henle is composed of what kind of tissue? The ascending limb of the loop of Henle is composed of what kind of tissue?
-simple squamous epithelium
-thin or thick: simple squamous epithelium or simple cuboidal to low columnar
(note: some nephrons contain both thick and thin ascending limbs)
Based on the length of the Loop of Henle and the presence of thin segments in the ascending limb, nephrons can be assorted into two different populations. What are they?
1. cortical (short)
2. juxtamedullary (long)
(nephrons with long loops of Henle enable the kidneys to create a concentration gradient in the renal medulla and to excrete very dilute or concentrated urine)
Cortical nephrons: their renal corpuscles (glomerulus and bowman's capsule) are located in the outer portion of the ______________, with short loops of Henle that penetrate only a small way into the _____________.
-cortex
-medulla
Cortical nephrons: their ascending limbs of their loops of Henle consist of only a ____________ segment, lacking any ____________ portions. Nephrons with short loops receive their blood supply from ____________ capillaries that arise from efferent arterioles.
-thick
-thin
-peritubular
List the steps of the flow of fluid through a cortical or juxtamedullary nephron. (pattern is same. It's just the long loop that allows for concentration and such)
1. Glomerular (Bowman's) Capsule -->
2. Proximal convoluted tubule -->
3. Descending limb of nephron loop -->
4. Ascending limb of nephron loop -->
5. Distal convoluted tubule -->
(drains into collecting duct)
Juxtamedullary nephrons: their renal corpuscles lie deep in the _____________, close to the _____________, and they have long loops of Henle that extend into the deepest regions of the medulla.
Juxtamedullary nephrons: the ascending limbs of their hoops of Henle consist of _______________ segments. Nephrons with long loops receive their blood supply from the _____________ that arise from peritubular capillaries before becoming peritubular venules.
-thick and thin
-vasa recta
In each nephron, the final part of the ascending limb of the Loop of Henle makes contact with the afferent arteriole serving that renal corpuscle. Because the columnar tubule cells in this region are crowded together, they are known as the _____________.
-macula densa
The cells of the macula densa are sensitive to the ionic content and water volume of the fluid in the tubule. If low water volume is detected by these cells, they will produce molecular signals that promote _____________ secretion by other cells of the juxtaglomerular apparatus called the juxtaglomerular cells.
-renin
The release of renin is an essential component of the renin-angiotensin-aldosterone system (RAAS), which regulates _________________.
-blood pressure and volume
Alongside the macula densa, the wall of the afferent arteriole contains modified smooth muscle fibers called _________________.
-juxtaglomerular (JG) cells
Together, the macula dense and juxtaglomerular cells constitute the ___________________.
-juxtaglomerular apparatus (JGA)
The juxtaglomerular apparatus helps regulate ______________ in the kidneys.
-blood pressure
Regulating glomerular blood pressure regulates _________________.
-glomerular filtration rate (GFR)
What are the three basic functions performed by the nephrons and collecting ducts?
1. glomerular filtration
2. tubular reabsorption
3. tubular secretion
Glomerular filtration: pressure forces filtration of waste-laden ______________ in the glomerulus. The _____________ is the amount of filtration formed in all of the renal corpuscles of both kidneys each minute.
-blood
_______________ is the process of returning important substances from the filtrate back to the body.
-tubular reabsorption
_______________ is the movement of waste materials from the body to the filtrate.
-tubular secretion
_______________ is the formation of a protein-free filtrate (ultrafiltrate) of plasma across the plasma membrane
-glomerular filtration
Only a portion of the blood plasma delivered to the kidney via the renal artery is filtered. Plasma which escapes filtration, along with its protein and cellular elements, exits the renal corpuscle via the _______________, perfuses the capillary beds, and is eventually connected in the renal venous system
What percent of blood gets filtered and what percent doesn't?
-20% gets filtered
-80% doesnt
In the average adult, the body's entire extracellular fluid volume is filtered about ____ times per day. Since we cannot afford to lose that amount of fluid, the vast majority must be reclaimed, with just a small portion being excreted in the urine.
The average human might produce ____________ or more gallons a day.
How much water is in the total amount of plasma?
-3L
Filtration is controlled by 2 opposing ___________ forces and 2 opposing _____________ forces at the glomerular membrane called ______________.
-hydrostatic
-osmotic
-starling forces
_______________ is the main force that "pushes" waters and solutes through the filtration membrane (promotes filtration)
-blood hydrostatic pressure (55mmHg)
______________ is the force exerted against the filtration membrane by fluid in the capsular space (opposes filtration)
-capsular hydrostatic pressure (15mmHg)
_____________ is the pressure of plasma proteins "pulling" on water (opposes filtration)
-blood osmotic (oncotic) pressure (30mmHg)
(there is also capsular osmotic pressure but normally, very little protein escapes through the filtration membrane, making capsular oncotic pressure a neglible or unimportant force except in disease states)
Normally, 3 Starling Forces are active and at work in glomerular filtration. What are they?
1. blood hydrostatic pressure (55)
2. capsular hydrostatic pressure (15)
3. blood colloid osmotic pressure (30)
Say whether the substances are passive or active in glomerular filtration.
-water
-protein
-glucose
-passive
-active
Comparing daily composition of plasma, filtrate, and urine are compared: Water.
-How much is in total amount of plasma?
-What is the amount in 180L of filtrate a day?
-What is the amount returned to the blood (reabsorbed)?
-What is the amount in urine a day?
-180L
-178-179L
-1-2L
Comparing daily composition of plasma, filtrate, and urine: _____________ is completely reabsorbed and not in urine while _______________ is all in urine and none is reabsorbed by the blood and body.
-creatinine
Regulation of the glomerular filtrate rate is critical to maintaining homeostasis and is regulated by an assortment of local and systemic mechanisms: name the three of them we've discussed.
1. renal autoregulation
2. neural autoregulation
3. hormonal regulation
Regulation of GFR: ________________ occurs when the kidneys themselves regulate GFR.
-renal autoregulation
Regulation of GFR: neural autoregulation occurs when the ___________ regulates renal blood flow and GFR.
-ANS (autonomic nervous system)
Regulation of GFR: hormonal regulation involves _______________ and ________________.
-angiotensin II
-atrial natriuretic peptide (ANP)
Renal autoregulation occurs by two means:
1. stretching in the glomerular capillaries triggers _____________ of smooth muscle cells in _____________ arterioles. Does this increase or decrease GFR?
-myogenic contraction
-afferent
-decrease
2. Pressure and flow monitored in the _________________ provides ____________________ to the glomerulus, causing the afferent arterioles to constrict (doing what to GFR?) or dilate (doing what to GFR?) appropriately.
-tubuloglomerular feedback
-decrease GFR
-increase GFR
Neural regulation of GFR is possible because the renal blood vessels are supplied by ______________________ fibers that release ________________, causing vasoconstriction.
-sympathetic ANS
-norepinephrine
____________ input to the kidneys is most important with extreme drops of Blood Pressure (as occurs with hemorrhage)
-sympathetic
(car accident bleeding out example: stopping blood to kidneys so it can go to more important places)
Two hormones contribute to glomerular filtration rate: what are they?
1. angiotensin II
2. atrial natriuretic peptide (ANP)
Angiotensin II is a potent _______________ of both afferent and efferent arterioles, increases or decreases GFR?
-vasoconstriction
-decreases
A sudden large increase in blood pressure stretches the cardiac atria and releases _______________.
-ANP (atrial natriuretic peptide)
_______________ causes the glomerulus to relax, increasing or decreasing the surface area for filtration?
Angiotensin II ________________ GFR while ANP _________________ GFR.
-increases
The Filtration Membrane has three filtration barriers:
1. _________________ (pores) of glomerular _____________ cells: prevents filtration of blood cells but allows all components of blood ____________ to pass through
-fenestrations
-endothelial
-plasma
2. _______________ of glomerulus: prevents filtration ____________ proteins.
-basal lamina
-larger
3. ______________ between pedicels: prevents filtration of _______________ proteins.
-slit membrane
-medium sized
Renal blood flow can be regulated by adjusting:
-blood flow in and out of the glomerular capillaries
-_______________ of glomerular capillaries
-There are three main ways to make these adjustments
2. neural regulation
-surface area
What are the three pressures that drive glomerular filtration?
1. blood hydrostatic pressure (55mmHg)
2. capsular hydrostatic pressure (15mmHg)
3. blood colloid osmotic pressure (30mmHg)
(note: Test question might be Dr. Huggins giving us the different pressures and us have to give him net filtration pressure: GBHP - CHP - BCOP
_______________ is the process of returning important substances ("good stuff") from the filtrate back into the renal interstitium, then into the renal blood vessels...and ultimately back in the body.
What is some of the "good stuff" in tubular reabsorption?
-electrolytes
-vitamins
-amino acids
-any small proteins that might have inadvertently escaped from the blood into filtrate
What percentage of filtrate is reabsorbed?
-99% (most of it before the end of the proximal convoluted tubule - PCT)
In addition to being filtered and reabsorbed, the urea is also _______________.
-secreted
After virtually all filtered K+ is reabsorbed in the ________________ and ______________, a variable amount of K+ is ______________ by the _____________ cells in the collecting duct.
-convoluted tubules
-loop of Henle
-principal
(principal cells secrete K+)
Reabsorption into the renal interstitium has two routes: what are they?
1. paracellular reabsorption
2. transcellular reabsorption
Paracellular reabsorption is a _____________ process that occurs between _________________ (tight junctions do not completely seal off interstitial fluid from tubule fluid)
-adjacent tubule cells
(note: para means around)
Transcellular reabsorption is movement through a ______________.
-individual cell
(note: transcellular means across the cell)
It is a tremendous feat to reabsorb all of the nutrients and fluid we must to survive, while still filtering out, concentrating, and excreting toxic substance. To accomplish all of this, the kidney establishes a _____________ between the filtrate in the limbs of the Loop of Henle and the blood in the peritubular capillaries and vasa recta.
-countercurrent flow
Two types of countercurrent mechanisms exists in the kidneys: what are they?
1. countercurrent multiplication
2. countercurrent exchange
Countercurrent multiplication is the process by which a progressively increasing ____________ gradient is formed in the interstitial fluid of the ________________ as a result of countercurrent flow.
-renal medulla
Countercurrent exchange is the process by which solutes and water are _____________ exchanged between the blood of the ____________ and interstitial fluid of the _____________ as a result of countercurrent flowl
-passively
The vasa recta is seen to function as a __________________.
-countercurrent exchanger
Both countercurrent multiplication and countercurrent exchange contribute to reabsorption of fluid and electrolytes and the formation of concentrated urine. Countercurrent flow in the loop of Henle established an osmotic gradient that increases from ________________ in the outer medulla to ______________ in its deeper portions.
-300 mOsm/L
-1200 mOsm/L
Reabsorption of water can be ______________ or ______________, but it always moves by osmosis down its concentration gradient depending on the ____________ of the tubule cells (which vary between the PCT, the different portions of the Loop of Henle, DCT, and collecting ducts)
-obligatory
-facultative
-permeability
Obligatory reabsorption of water occurs when it is ____________ to follow the solutes as they are reabsorbed (to maintain osmotic gradient)
-obliged
Principal cells become more _____________ to water, which increases or decreases facultative reabsorption?
-permeable
This graphic depicts the formation of concentrated urine by the action of ADH on the DCT and collecting ducts of juxtamedullary nephrons.
What's another name for dilute urine? What's another name for concentrated urine?
-hypo osmotic or hypotonic
-hyper osmotic or hypertonic
Regulation of osmolarity of body fluid depends on:
- formation of ______________ osmotic gradient
-amount of _______ present at the collecting ducts
-medullary
-ADH
If higher than normal amounts of a substance are present in the filtrate, then the _____________ for reabsorption of that substance may be surpasses
-renal threshold
When the renal threshold is surpassed, the substance cannot be reabsorbed fast enough, and it will be what?
-excreted in the urine
________________________ is the movement of substances from the capillaries which surround the nephron into the filtrate.
Tubular secretion occurs at a site other than the filtration membrane (in the PCT, DCT, and collecting ducts) by what?
-active transport
What does the process of tubular secretion control?
______________ and _____________ ions are secreted to decrease acidity in the body
-hydrogen
-ammonium
While hydrogen and ammonium ions are secreted to decrease acidity in the body, _______________ is conserved.
-bicarbonate
If our bodies are really acidic, we want to get rid of __________ and save ____________ because they are alkalinic.
-hydrogens
-bicarbonates
Maintaining the body's proper pH requires cooperation mainly between the _____________ and the ____________
-lungs
When it comes to maintaining proper pH, the lungs eliminate ___________, provided a rapid response within minutes
-CO2
The alimentary canal (digestive) and _____________ provide minor contributions as well.
-integumentary (skin)
There are five hormones that affect the extent of Na+, Cl-, Ca2+, and water reabsorption as well as K+ secretion by the renal tubules. These hormones, all of which are key to maintaining homeostasis of not only the renal blood flow and blood pressure, but systemic blood flow and blood pressure. What are these five hormones?
2. antidiuretic hormone (ADH) <--- says to save water and don't tinkle
3. aldosterone <--- goes after sodium
5. parathyroid hormone (PTH) <--- calcium
ADH is released by the posterior ________________ in response to __________ blood flow in this part of the brain. ADH affects facultative water reabsorption by doing what to the permeability of principal cells in the last part of the DCT and throughout the collecting duct.
-pituitary
-low
-increases permeability
In the absence of ADH, the apical membrane of principal cells are almost ________________ to water.
-impermeable
Secretion of the hormones angiotensin II and aldosterone are tied to one another: When volume and blood pressure decrease or the sympathetic nervous system is stimulated, the walls of the ______________ are stretched less, and the cells of the ____________ secrete renin.
-afferent arteriole
-JGA
(memorize picture on slide 63)
Renin clips off a _______ amino acid peptide called ____________________ from angiotensinogen, which is synthesized by hepatocytes. By clipping off two more amino acids, (ACE) converts angiotensin I to _______________________, which is the active form of the hormone.
-angiotensin I
-angiotensin II (active form)
Angiotensin II has three main effects: what are they?
1. vasoconstriction decreases glomerular filtration rate (GFR)
2. It increases blood volume by increasing reabsorption of water and electrolytes in the proximal convoluted tubule (PCT)
3. It stimulates the adrenal cortex to release aldosterone
The osmotic consequence of reabsorbing more Na+ and Cl- is that more water is reabsorbed, which increases what?
-blood pressure and blood volume
Aldosterone makes principal cells more permeable to water, which increases _____________________.
-facultative water reabsorption
At end of PCT, tubular fluid is still ___________. to blood at about ____________ mOsm/L. At the end of the loop of Henle, tubular fluid is _______________ at about __________mOsm/L. Tubular fluid leaving the collecting duct is ____________ when __________ level is low
-isotonic, 300
-hypotonic, 150
What do increases in glomerular filtration rate (GFR) usually lead do? However, as we have seen, the mechanisms which control electrolyte and water reabsorption in the various parts of the nephron and collecting ducts are subject to many complex controls. What is the normal UOP (urine output)?
-increase in urine
-1 to 2 L (1.5L) a day
Characteristics of normal urine: Color: yellow or amber, varies with urine concentration or diet. Color - due to urochrome (the pigment produced from breakdown of ______________), and urobilin (produced from the breakdown of _____________). Concentrated urine is darker in color. Color can also be affected by diet (like eating reddish beets), medications, and certain diseases. Kidney stones may produce blood in urine.
-bile
-hemoglobin
Characteristics of normal urine: Turbidity (cloudiness): Transparent when freshly voided; becomes cloudy on _______________.
Characteristics of normal urine: Odor. Mildly aromatic; becomes ______________ like on standing. Some people inherit ability to form methylmercaptan from digested ___________, which gives odor. Urine of diabetics have a fruity odor due to presence of ______________ bodies.
-ammonia
-asparagus
-ketone
Characteristics of normal urine: pH. Urine pH ranges from ___________ to ___________. The average is __________. This varies considerably with diet. High protein diets increase _______________ while vegetarian diets increase ___________________.
-acidity
-alkalinity
Characteristics of normal urine: Specific Gravity Density: specific gravity (density) is a ratio of weight of volume of substance to weight of equal volume of distilled water. In urine, ________________ to ______________ . The higher the concentration of solutes, the higher the specific ____________.
a ________________ analyzes the physical, chemical, and microscopic properties of urine.
-urinalysis
Water accounts for what percentage of total urine volume?
If disease alters metabolism or kidney function, traces of substances normally not present or normal components in abnormal amounts may appear. For example, bacteria, ____________ protein, glucose, white blood cells, red blood cells (just to name a few).
-albumin
In addition to urinalysis, two blood tests are commonly done clinically to assess the adequacy of renal function. What are they?
1. Blood urea nitrogen (BUN)
2. Serum Creatinine
Blood urea nitrogen (BUN) measures nitrogen wastes in blood from catabolism and deamination of ____________________.
The Serum Creatinine test measures the amount of creatinine in blood, which increases in the state of renal _____________.
-dysfunction
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