Urinary System Flashcards
Name the organs in the urinary system
- kidneys
- ureter
- urethra
- urinary bladder
The _______ gland sits atop the kidneys. Blood vessels enter and leave the kidney at the renal _________.
- adrenal
- hilum
The functional units of the kidneys are the ________. They are called _______ _________ if they are located mainly in the cortex. They are called _________ _________ if they are located in both the cortex and the medulla.
- nephrons
- cortical nephrons
- juxtamedullary nephron
Blood enters the kidney through the _________ artery. The artery branches into smaller and smaller arteries and arterioles. Complete the sequence below:
________ arteriole —-> _________ capillaries —–> ________ arteriole —-> _________ capillaries and vasa recta
- renal
- afferent
- glomerulus
- efferent
- peritubular
Complete the sequence below showing all parts of the nephron:
Glomerular (Bowman’s) capsule —-> ________ convoluted tubule —-> _____________ —-> _________ convoluted tubule —-> ______________
- proximal
- loop of henle
- distal
- collecting duct
The renal corpuscle consists of two parts: _______ capillaries and the __________.
- glomerulus
- Bowman’s capsule
The filtration membrane consists of ____________ capillary endothelium, porous ________ membrane, and the _______. This filtration membrane permits (large or small) molecules to be filtered.
- fenestrated
- basement
- podocytes
- small
The simple cuboidal cells of the proximal tubule contain numerous microvilli. The microvilli increase the ____________ for reabsorption.
-surface area
The thin descending limb of the loop of henle is highly permeable to _____ but not _________.
- water
- ions (salt)
The thick ascending limb of the loop of henle is highly permeable to ________ but not to ______.
- ions (salt)
- water
The juxtaglomerular apparatus consists of
________ cells serve as baroreceptors sensitive to blood pressure within the arteriole.
________ cells monitor and respond to changes in the osmolarity of the filtrate in the tubule.
________ cells that can contract and can act as phagocytes.
- JG cells
- macula densa
- mesangial
The cortical collecting duct contains two functional types of cells:
_______ cells - hormones regulate their permeability to water and solutes.
_______ cells - secrete hydrogen ions for acid-base regulation.
- principal
- intercalated
What force drives filtration at the glomerulus?
hydrostatic pressure of glomerulus
Blood pressure in the glomerulus is about ___ mmHg.
55
What two pressures oppose filtration and what are their values?
- Hydrostatic pressure - 15 mmHg
2. Osmotic Pressure - 30 mmHg
What is the normal net filtration pressure?
10 mmHg
In an exercising individual the afferent arteriole will (dilate or constrict) to avoid excess fluid loss.
constrict
(True or False)
When the sodium concentration in the filtrate is high, the macula densa cells vasodilate that afferent arteriole.
false
If a tumor of the glucocorticoid-secreting cells of the adrenal gland crowds out the cells that produce aldosterone, what is the likely effect on urine composition and volume?
- aldosterone levels decrease
- sodium in urine increases
- volume of urine increases because H2O follows sodium
(True or False)
The bicarbonate buffer system is the most important buffer in the intracellular compartment.
false
*Extracellular
How would the body compensate for metabolic acidosis?
increase in breathing rate
What is not a function of the kidney?
vitamin deactivation
Tubular reabsorption ____________.
could use secondary transport as a way to transport substances to the blood
(True or False)
Blood pressure in the renal glomerulus is higher than in most parts of the body.
true
Hyperventilation could cause
respiratory alkalosis
The fluid in the glomerular capsule is similar to the plasma. However, you will not see the presence of
erythrocytes
(True or False)
The GFR is between 140-155 mL/min
false
Know the different membranes covering the kidney and the importance for each one.
- Renal capsule: fibrous capsule that prevents kidney infection
- Adipose capsule: fatty mass that cushions the kidney and helps attach it to the body wall
- Renal fascia: outer layer of dense fibrous connective tissue that anchors the kidney
Be able to understand the anatomy of the kidney including, calyces, cortex, medulla, renal hilum, renal corpuscle renal pelvis, etc.
- major calyces: large branches of renal pelvis, collect urine draining from papilla, empty urine into the minor calyces and then pelvis
- minor calyces: branches of major calyces which collect urine formed in the papilla from the medullary pyramids
- cortex: light colored; superficial region
- medulla: consists of renal pyramids
- renal hilum: indentation where blood vessels, lymphatics, ureters, and nerves exits and enter the kidney
- renal corpuscle: the glomerulus region
- renal pelvis: middle of kidney
Be able to demonstrate knowledge on the flow of blood through a kidney
aorta —> renal artery —> segmental artery —> interlobar artery —> arcuate artery —> cortical radiate artery —> afferent arteriole —> glomerulus —> efferent arteriole —> peritubular capillaries or vasa recta —> cortical radiate vein —> arcuate vein —> interlobar vein —> renal vein —> inferior vena cava
What is the structural and functional unit of the kidney?
the nephron
Know the structures that make up the nephron and their histology.
- glomerulus: filters small solutes from the blood
- PCT: reabsorbs ions, water, and nutrients; removes toxins and adjusts filtrate pH
- descending LOH: aquaporins allow water to pass from the filtrate into the interstitial fluid
- ascending LOH: reabsorbs sodium and chloride from the filtrate into the interstitial fluid
- DCT: selectively secretes and absorb different ions to maintain blood pH and electrolyte balance
- collecting duct: reabsorbs solutes and water from the filtrate
Contrast blood pressure in the glomerulus and other parts of the body. What other structural differences exist between the glomerulus and other body capillaries?
Due to arterioles being high-resistance vessels and afferent arterioles having larger diameters than efferent, blood pressure is high.
What is the chief force pushing water and solutes out of the blood into the glomerular capsule?
glomerular hydrostatic pressure
Explain the differences between blood plasma and renal filtrate and relate the differences to the structure of the filtration membrane.
Renal filtrate is a solute-rich fluid without blood cells or plasma proteins because the filtration membrane is permeable to water and all solutes smaller then plasma proteins.
What is the filtration membrane and what is it made of?
- filtration membrane: made up of three layers
1. fenestrated capillary endothelium: capillary pores prevent passage of blood cells
2. podocytes: restricts all but small proteins
3. intervening basement membrane: provides no restriction in passage of molecules
How much blood is filtrated in one day and how much urine is eliminated from the body in one day?
- 200 liters of blood is filtrated
- anywhere between thirty-two to sixty-four ounces of urine
What is the juxtaglomerular apparatus (JGA) responsible for? What cells make part of the JGA and what are their functions?
play important role in forming concentrated urine, responsible for reabsorption of organic molecules, vitamins, and water.
- JG cells: sensing cells blood pressure in the walls of afferent arterioles near the glomerulus
- Macula densa cells: osmoreceptors responding to changes in solute concentration of filtrate
- Mesangial cells: these cells in glomerulus of the JGA can contract changing surface area of capillaries available for filtration
What is GFR and what is the normal GFR in the kidney? What happens to the reabsorption of substances if GFR is too high or too low?
Glomerular Filtration Rate: the total amount of filtrate formed per minute by the kidneys; 120 - 125 ml/min
-if too high (higher than 125 ml/min)
needed substances can not be reabsorbed quickly enough and are lost in the urine
-if too low (lower than 120 ml/min)
everything is reabsorbed, including wastes that are normally disposed of
Name the two types of nephrons and their percentage.
cortical: 85% of nephrons are located in the cortex of the kidney except for small part of loop of henle that dip into outer medulla
juxtamedullary: 15% of nephrons are involved in production of concentrated urine part of the loop henle located at the cortex medullary junction, penetrates into medulla, have extensive thin segments.
Study the table we did in class. Reabsorption
*LOOK AT BACK OF NOTES
What is Tm and what is its importance? What happens to nutrients when the nutrient abundance is higher?
a transport maximum (Tm) reported in mg/min:
-reflects the number of carriers available to ferry each particular substance in the renal tubules
Define osmolality
- The number of solute particles in 1L of water
- Reflects the solutions ability to cause osmosis
What is the purpose of the countercurrent mechanism?
- filtrate flow in the LOH
- creates and maintains an osmotic gradient in medulla
- allow the kidneys to vary urine concentration
What are the main functions of the ureter, bladder and urethra?
- ureters: transport urine from the kidneys to the bladder ( stratified, transitional epithelium)
- bladder: provides a temporary storage reservoir for urine (transitional epithelium)
- urethra: transports urine from the bladder out of the body (stratified columnar epithelium)
How does the urinary bladder anatomy support its storage function?
- the bladder has three layers of smooth muscle and a transitional epithelium
- the mucosa is heavily folded, this helps to accomodate for large volume changes
- the transitional epithelial lining can stretch until it looks like stratified squamous epithelium
Define micturition. What can trigger the initiation of micturition?
The act of emptying the bladder
Parasympathetic
- contraction of detrusor muscle
- relaxation of internal urethral sphincter
Motor neurons - inhibited
- skeletal muscle - relaxed
- external urethral sphincter opens
Be able to discuss characteristics of urine.
color and transparency
- clear, pale to deep yellow
- concentrated urine has a deeper yellow color
- drugs, vitamin supplements, and diet can change the color of urine
- cloudy urine may indicate infection of the urinary tract
odor
- fresh urine is slightly aromatic
- standing urine develops an ammonia odor
- diabetes mellitus makes urine smell fruity
slightly acidic (pH 6) with a range of 4.5 to 8.0
specific gravity ranges from 1.001 to 1.035
urine is 95% water and 5% solutes
nitrogenous wastes: urea, uric acid, and creatinine
Freshly voided urine has very little smell, but shortly after voiding it can take a very strong smell. Why?
standing urine develops an ammonia odor
What are the sources of gain or loss of water?
- gain: ingestion, ingested food, and metabolism
- loss: urine, perspiration, lungs, and GI
Name the body fluid compartments, noting their location and the approximate fluid volume in each.
-intracellular fluid (ICF):
2/3 by volume contained in cells
-extracellular fluid (ECF):
1/3 by volume
plasma- the fluid portion of the blood
interstitial fluid- fluid in spaces between cells
How is the movement among compartments regulated?
osmotic and hydrostatic pressures
What situations could trigger thirst?
- plasma volume 10%-15%
- plasma osmolality 1%-2%
- moistened mucosa of mouth/throat
- activation of stomach/intestinal
- dry mouth
Why are salts important in your body?
- controlling fluid movements
- membrane permeability
What two main organs are involved in the buffer systems?
- lungs
- kidneys
Which ion is linked blood pressure?
sodium
What is major homeostatic challenge of the acid-base balance? Or what could your body control to maintain the proper pH of the body fluids?
- keeping hydrogen ion concentration (pH) of body fluids
- Blood and other fluids, lungs, and kidneys
What is the most important blood buffer system?
protein buffer system
Name the sources of hydrogen ions.
- aerobic respiration of glucose release: carbonic acid
- anaerobic respiration of glucose produces: lactic acid
- oxidation of sulfur-containing amino acids: sulfuric acid
- incomplete oxidation of fatty acids yield: acidic ketone bodies
- hydrolysis of phosphoproteins and nucleic acids releases: phosphoric acids into ECF
- transporting carbon dioxide as bicarbonate: releases hydrogen ions
