Kidneys Flashcards
Which of the following transports urine toward the urinary bladder?
A. Kidneys
B. Ureter
C. Urinary bladder
D. Urethra
B. Ureter
Ureter: transports urine toward the urinary bladder
Urethra: Conducts urine to exterior; in males, transports semen as well
Each kidney is protected and stabilized by three concentric layers of connective tissue. Which of the following layers surrounds the renal capsule?
A. Fibrous capsule
B. Perinephric fat capsule
C. Renal fascia
B. Perinephric fat capsule
Fibrous capsule = covers outer surface of entire organ
Perinephric fat capsule = surrounds renal capsule
Renal fascia = anchors kidney to surrounding structures
Each kidney is protected and stabilized by three concentric layers of connective tissue. Which of the following layers surrounds the outer surface of the entire organ?
A. Fibrous capsule
B. Perinephric fat capsule
C. Renal fascia
A. Fibrous capsule
Each kidney is protected and stabilized by three concentric layers of connective tissue. Which of the following layers anchor the kidneys to surrounding structures?
A. Fibrous capsule
B. Perinephric fat capsule
C. Renal fascia
C. Renal fascia
All of the following structures of the nephron are located within the cortex of the kidney EXCEPT:
A. Glomerulus
B. Bowman’s capsule
C. Loop of Henle
D. Proximal tubule
E. Distal tubule
C. Loop of Henle
note: Loop of Henle and collecting tubule are located in the medulla
All of the following are vascular components of the nephron EXCEPT:
A. Afferent arteriole
B. Efferent arteriole
C. Glomerulus
D. Peritubular capillaries
E. Bowman’s capsule
E. Bowman’s capsule
Which of the following components of the nephron carries blood from the glomerulus?
A. Afferent arteriole
B. Efferent arteriole
C. Glomerulus
D. Peritubular capillaries
B. Efferent arteriole
Afferent arteriole = carries blood TO the glomerulus
Efferent arteriole = carries blood FROM the glomerulus
Glomerulus = a tuft of capillaries that filters a protein-free plasma into the tubular component
Peritubular capillaries = supply the renal tissue; involved in exchanges with the fluid in the tubular lumen
Which of the following components of the nephron contains a tuft of capillaries that filters a protein-free plasma into the tubular component?
A. Afferent arteriole
B. Efferent arteriole
C. Glomerulus
D. Peritubular capillaries
C. Glomerulus
Which of the following components of the nephron collects glomerular filtrate?
A. Glomerulus
B. Bowman’s capsule
C. Proximal tubule
D. Loop of henle
E. Distal tubule and collecting duct
B. Bowman’s capsule
Uncontrolled reabsorption and secretion of selected substances occurs in the ______.
A. Glomerulus
B. Bowman’s capsule
C. Proximal tubule
D. Loop of henle
E. Distal tubule and collecting duct
C. Proximal tubule
Controlled reabsorption of sodium and water and secretion of potassium and hydrogen occur in the _______.
A. Glomerulus
B. Bowman’s capsule
C. Proximal tubule
D. Loop of henle
E. Distal tubule and collecting duct
E. Distal tubule and collecting duct
Which of the following establishes an osmotic gradient in the renal medulla that is important in the kidney’s ability to produce urine of varying concentrations?
A. Glomerulus
B. Bowman’s capsule
C. Proximal tubule
D. Loop of henle
E. Distal tubule and collecting duct
D. Loop of henle
Which of the following is a combined vascular and tubular component that produces substances involved in the control of kidney function?
A. Glomerulus
B. Bowman’s capsule
C. Loop of henle
D. Juxtaglomerular apparatus
D. Juxtaglomerular apparatus
Discuss the Glomerular capsule aka Bowman’s capsule:
- Discuss the structure and composition
- Discuss the outer layer
- Discuss the inner layer
Bowman’s capsule
- Double-walled structure composed of squamous epithelium
Outer layer is continuous with epithelium of proximal tubule
Inner layer composed of podocytes that are closely assoiated with glomerular capillaries
The glomerulur filtration membrane allows the passage of all of the following EXCEPT:
(select all that apply)
A. Glucose
B. Blood cells
C. Vitamins
D. Metabolic wastes
E. Most plasma proteins
B. Blood cells
E. Most plasma proteins
Mesangial cells provide support to glomerulur capillaries. What are the 4 functions of Mesangial cells?
- Contain actin and are contractile (can alter bood flow in capillaries)
- Secrete inflammatory cytokines
- Synthesize matrix
- Phagocytosis
All of the following are true about the Proximal convoluted tubule EXCEPT:
A. Continuous with epithelium of glomerular capsule
B. Lined with flat squamous cells that lack microvilli
C. Single layer of cuboidal cells containing microvili
D. Many mitochondria (energy for active transport)
B. Lined with flat squamous cells that lack microvilli
Proximal convoluted tubule
- Continuous epithelium of glomerular capsule
- Single layer of cuboidal cells containing microvilli
- Many mitochondria (energy for active transport)
Which of the following begins at the macula densa and is a mass of specialized epithelial cells of the tubule wall?
A. Proximal convoluted tubule
B. Ascending loop of henle
C. Descending loop of henle
D. Distal convoluted tubule
D. Distal convoluted tubule
Which of the following is true regarding the proximal convoluted tubule?
A. Single layer of cuboidal cells containing microvilli
B. Lined with flat squamous cells that lack microvilli
C. Lined with cuboidal cells that lack microvilli
D. Single layer of cuboidal cells that lack microvilli
A. Single layer of cuboidal cells containing microvilli
Proximal convoluted tubule:
- cuboidal cells containing microvilli
- Many mitochondra - energy for active transport
Which of the following contains a brush border?
A. Proximal convoluted tubule (PCT)
B. Distal convoluted tubule (DCT)
A. Proximal convoluted tubule (PCT)
What are the 3 functions of the Urinary system?
Excretion, elimination, and homeostatic regulation
What are the 10 functions of the kidney?
- Water balance
- Osmolarity
- Regulating quantity and concentration of most ECF ions (sodium, chloride, potassium, hydrogen)
- Maintaining plasma volume and regulating blood pressure
- Acid-base balance
- Eliminating wastes
- Excreting foreign compounds such as drugs
- Produces erythropoietin
- Produces renin
- Converting vitamin D
Blood in urine is termed ______.
A. Hematuria
B. Hemodialysis
C. Nocturia
D. Polyuria
E. Uremia
A. Hematuria
Which of the following is a method of clearing waste products from the blood?
A. Hematuria
B. Hemodialysis
C. Nocturia
D. Polyuria
E. Uremia
B. Hemodialysis
Which of the following is excessive urine output?
A. Hematuria
B. Hemodialysis
C. Nocturia
D. Polyuria
E. Uremia
D. Polyuria
Which of the following is night urination?
A. Hematuria
B. Hemodialysis
C. Nocturia
D. Polyuria
E. Uremia
C. Nocturia
_______ is the retention of urinary constituents in the blood.
A. Hematuria
B. Hemodialysis
C. Nocturia
D. Polyuria
E. Uremia
E. Uremia
_______ is “water in the kidney”.
A. Hematuria
B. Hemodialysis
C. Hydronephrosis
D. Polyuria
E. Uremia
C. Hydronephrosis
______ is inflammation of the urinary bladder.
A. Cystitis
B. Hemodialysis
C. Hydronephrosis
D. Polyuria
E. Uremia
A. Cystitis
What are the 6 main components of the Nephron?
- Glomerulus
- Bowman’s capsule
- Proximal convoluted tubule
- Loop of henle
- Distal convoluted tubule
- Collecting duct
Which of the following is permeable to H2O?
A. Ascending loop of henle
B. Descending loop of henle
C. Distal convoluted tubule
D. Macula densa
B. Descending loop of henle
Which of the following contain Principal cells?
A. Proximal convoluted tubule
B. Distal convoluted tubule
C. Loop of henle
D. Collecting duct
D. Collecting duct
Collecting duct
- Contains principal cells - absorb Na+, secrete K+ and responds to ADH
- Contains a-intercalated cells - secrete H+ and reabsorb bicarbonate for acid-base homeostasis
Which of the following responds to ADH?
(select all that apply)
A. Proximal convoluted tubule
B. Distal convoluted tubule
C. Loop of henle
D. Collecting duct
B. Distal convoluted tubule
D. Collecting duct
Which of the following cells of the collecting duct is responsible for acid-base homeostasis?
A. Principal cells
B. a-intercalated cells
B. a-intercalated cells
a-intercalated cells secrete H+ and reabsorb bicarbonate
Which of the following cells of the collecting duct responds to ADH, absorbs Na+ and secretes K+?
A. Principal cells
B. a-intercalated cells
A. Principal cells
How much fluid does the kidney filter a day?
45 gallons/day
Which of the following pulls the good stuff out?
A. PCT
B. DCT
A. PCT
DCT = bad stuff excreted
When arteriolar vasodilation occurs, Glomerular capillary blood pressure ________, Net filtration pressure ________ and ultimately GFR ________.
A. increases, increases, increases
B. decreases, decreases, descreases
C. increases, decreases, increases
D. decreaess, increases, decreases
A. increases, increases, increases
Vasodilation = increases GFR
Vasoconstriction = decreases GFR
When arteriolar vasoconstriction occurs, Glomerular capillary blood pressure ________, Net filtration pressure ________ and ultimately GFR ________.
A. increases, increases, increases
B. decreases, decreases, descreases
C. increases, decreases, increases
D. decreaess, increases, decreases
B. decreases, decreases, descreases
note: if you squeeze a waterhose less water will come out
note: vasoconstriction decreases blood flow into the glomerulus
All of the following are components of a podocyte EXCEPT?
A. Endothelial fenestrations
B. Basement membrane
C. Slit membrane between pedicels
D. All of the above are components of a podocyte
D. All of the above are components of a podocyte
Podocyte = fenestrations, slits, and basement membrane
Which of the following is a the normal Tm of glucose filtered?
(select all that apply)
A. 375 mg/min
B. 120 ml/min
C. 125 ml/min
D. 100 mg/min
A. 375 mg/min
Which of the following is a normal glomeurlar filtration rate (GFR)?
(select all that apply)
A. 375 mg/min
B. 120 ml/min
C. 125 ml/min
D. 370 mg/min
B. 120 ml/min
C. 125 ml/min
GFR = 120 ml/min
Tm of glucose = 375 mg/min
- _______ is the portion of the blood plasma that enter the glomerular capsule.
- How much is filtered a day?
Glomerular filtrate is the portion of the blood plasma that enter the glomerular capsule.
45 gallons
Discuss glomerular filtrate:
- Define glomerular filtrate
- How much is filtered a day?
- What are the 2 mechanisms that cause fluid fluid filtrate?
- What 3 things are too large to be filtered?
Glomerular filtrate is the portion of the blood plasma that enters the glomerular capsule.
- 45 gallons/day
- High hydrostatic pressure and Large quantities of pores
- Plasma proteins, Blood cells (WBCs and RBCs), and platelets
Glomerular filtrate contains all of the following EXCEPT:
A. water
B. glucose
C. electrolytes
C. plasma proteins
C. plasma proteins
Glomerular filtrate contains water, electrolytes and glucose
Only substances with a molecular weight less than ______ are able to fit through the tiny pores to enter the glomerular capsule and become glomerular filtrate.
60,000 daltons
note: albumin (MW = 68,000 daltons) is a plasma protein that is too large to be filtered
What is the GFR equation?
GFR = Urine x Urine / plasma
Normal GFR = 120 ml/min
What two things influence filtration rate?
- Glomerular blood pressure and flow
- Size of the filtration slits/pores
________ is the transfer of fluid and solutes out of the lumen of the nephron into the interstitial space, and into the peritubular capillaries.
Tubular reabsorption
Note: approximately 99% of the filtrate is reabsorbed from the renal tubules
Discuss tubular reabsorption:
- Where does tubular reabsorption primarily occur?
- The transport of substances occurs via ______ transport
- What two ways does this accomplish it? hint: one of the ways requires energy
Tubular reabsorption
- Occurs primarily in the proximal convoluted tubule
- The transport of substances occurs via trans-epithelial transport
- Diffusion - no energy; and Active transport - requires energy (thats why mitochondria are abundant)
99.5% of Na is reabsorbed in tubular reabsorption (67% is reabsorbed in the PCT). ______ is a hormone that regulates reabsorption in the DCT and collecting duct.
Aldosterone
List each of the following in order of where most Na+ reabsorption occurs to least:
- PCT
- DCT
- Loop of Henle
PCT > Henle > DCT
_______ regulates the reabsorption of Na+ in the DCT and collecting duct (renin-angiotensin-aldosterone system).
Aldosterone
Discuss tubular reabsorption regarding glucose:
- What percent of glucose filtered is reabsorbed in the proximal tubule?
- Occurs via ______ transport.
- The Transport maximum (Tm) of glucose filtered is _______.
Tubular reabsorption (glucose)
- 100% of glucose is reabsorbed in the proximal tubule
- Occurs via carrier-mediated transport
- Tm = 375 mg/min
Tubular secretion is the secretion of substances from the _______ into the _______ of the tubule for excretion in the urine.
Tubular secretion or movement of substances from the peritubular capillaries into the lumen of the tubule for excretion in the urine.
Tubular reabsorption is the transfer of fluid and solutes out of the lumen of the nephron into the interstitial space, and into the peritubular capillaries.
Tubular reabsorption = lumen —> capillaries
Tubular secretion = capillaries —> lumen
Tubules secrete each of the following EXCEPT:
A. H+
B. K+
C. Na+
D. Penicillin
C. Na+
Tubules secrete H+, K+ and penicillin
note: H+ secretion is important in the regulation of acid-base balance and can be secreted in all tubular regions
note: K+ is reabsorbed in the PCT and actively secreted in the DCT
note: K+ secretion is coupled to Na+ reabsorption
What is the difference between acidosis and alkalosis in tubular secretion?
Acidosis: increase in CO2 and decrease in HCO3; The net result is the H+ ions are excreted in the urine, and the Na+ HCO3 ions are retained.
Alkalosis: the ratio of HCO3 increases as the pH rises. The net result is that H+ ions are retained and bicarbonate ions are excreted
note: if acidosis occurs the body will excrete more H+ to bring the pH back to normal
What are the 5 mechanisms to regulate urine concentration?
(possibly an exam Q)
- Ascending limb actively transports negatively charged Cl- out of the tubular fluid into the medullary interstitium, Na+ follows because of charge
- The ascending limb is impermeable to water
- The fluid in the ascending limb becomes more dilute
- Ions are actively transported into the interstitium from the collecting duct; urea passively diffuses out of the collecting duct
- The thin-walled peritubular capillaries only contain about 1 to 2% of the total renal blood flow and as a result carries only a minute amount of medullary interstitial solutes are carried away from the renal medulla
How does ADH regulate urine concentration?
ADH = water retention
With low levels of ADH the distal tubules and collecting ducts become impermeable to water, despite the high osmotic gradient, little water is pulled into the medulla. Therefore, urine becomes very dilute.
More ADH = more water retention = less water is excreted in urine = urine is more yellow
________ is the ability of the kidneys to “clear” the plasma of substances in a specific length of time (usually ml/min).
Plasma clearance analysis
Discuss the juxtaglomerular apparatus:
- What does it regulate?
- What does it produce and secrete to regulate this?
Juxtaglomerular apparatus
- Regulates blood pressure by production and secretion of renin
- Renin increases BP
note: a decrease in blood volume of BP in afferent arterioles, or decrease in NaCl concentration in DCT (detected by macula densa) results in release of renin from juxtaglomerular cells
note: J cells (juxtaglomerular cells) secrete renin
Discuss the roles of the Macula densa and J cells in regards to blood pressure:
- Macula densa contains what type of receptors?
- J cells contain what type of receptors?
- How do each of the two systems above react to low BP?
Macula densa = Osmoreceptors
J cells = Mechanoreceptors
note: when BP is low, J cells release renin to increase BP
note: a decrease in BP causes osmoreceptors in the macula densa to signal J cells to release renin
note: a decrease in BP also directly signals J cells to release renin
Give a quick overview of 8 steps in the summary of renal function:
- basically just tell me what parts of the nephron are involved in which steps in the production of urine.
- Glomerulus
- PCT
- PCT and Descending limb
- Thick Ascending limb
- DCT and collecting ducts
- DCT and collecting ducts
- Vasa Recta
- Urine production
Discuss the first three steps in the production of urine through the nephron of kidneys:
- What part of the nephron is involved and what does it do?
- Glomerulus
* filtrate produced at renal corpuscle has the same compostition as blood plasma (minus plasma proteins) - PCT
- Active removal of ions and organic substances
- produces osmotic water flow out of tubular fluid
- reduces volume of filtrate
- keeps solutions inside and outside tubule isotonic
- PCT and Descending limb
- Water moves into peritubular fluids, leaving highly concentrated tubular fluid
- Reduction in volume occurs by obligatory water reabsorption
Discuss steps 4-6 in the production of urine through the nephron of kidneys:
What part of the nephron is involved and what does it do?
- Thick ascending limb
* Tubular cells actively transport Na+ and Cl- out of tubule - DCT and collecting ducts
- final adjustments in composition of tubular fluid
- osmotic concentration is adjusted through active transport (reabsorption or secretion)
- DCT and collecting ducts
- Final adjustments in volume and osmotic concentration of tubular fluid
- Exposure to ADH determines final urine concentration
Discuss steps 7-8 in the production of urine through the nephron of kidneys:
What part of the nephron is involved and what does it do?
- Vasa Recta
- absorbs solutes and water reabsorbed by nephron loop and the ducts
- maintains concentration gradient of medulla
- Urine production
* ends when fluid enters the renal pelvis
What are the 9 steps involved in micturition (urination)?
- bladder fills with urine
- stretch receptors in bladder send impulses to the sacral spinal cord
- sensory neurons send impulses to high brain centers
- parasympathetic nerve impulses stimulates detrusor muscle and the internal urethral sphincter
- detrusor muscle contracts and the internal sphincter relaxes
- the need to urinate is intensified
- urination can be prevented by voluntary contraction of the external urethral sphincter
- if decision is to urinate, the external urethral sphincter is relaxed
- The detrusor contracts and urine is released though urethra
