What are 4 examples of how the urinary system regulates blood volume and pressure?
1. Regulating NaCl levels in the blood
2. Adjusting the volume of water lost in urine
3. Releasing erythropoietin
4. Releasing renin
List the order of structures in the renal corpuscle that a substance must pass through during filtration
1. Capillary endothelium
2. Dense layer
3. Filtration slit
4. Capsular space
Under resting conditions, what is the typical rate of renal blood flow?
List in order the blood vessels that carry blood to the kidney.
1. Renal artery
2. Segmental artery
3. Interlober artery
4. Arcurate artery
5. Cortical radiate artery (interlobular)
6. Afferent arteriole
8. Efferent arteriole
9. Peritubular capillaries
Label the structures:
1. Renal cortex
2. Renal medulla
3. Renal pyramid
4. Minor calyx
5. Major calyx
6. Renal columns
7. Fibrous capsule
9. Renal papilla
11. Renal pelvis
12. Renal sinus
What is the normal composition of urine and why should we be concerned if urine contains protein?
2. Hydrogen ions
4. Amino acids
5. Proteins are not normally present in urine because they are too big to pass through the filtration membrane. If protein (or RBCs) are present in urine, it means that there is structural damage in the glomerulus
What is the renal threshold for glucose and what happens if the level of glucose exceeds the threshold?
2. If plasma glucose levels exceed 180mg/dL, glucose appears in urine
What are the effects of sympathetic stimulation of the kidney?
1. Vasoconstriction of afferent arterioles
2. Decreased GFR (slows the production of filtrate)
3. Reduces blood flow to kidneys
4. Triggers release of renin
5. Renal ischemia
Approximately how many liters of filtrate enter the glomerular capsule each day?
1. 180L per day
How do you calculate the Net Filtration Pressure (NFP)?
1. NFP =BHP - (CsHP + BCOP)
2. BHP - CsHP = Net hydrostatic pressure (NHP)
What are some mechanisms the kidney uses to increase blood pressure?
1. Stimulate production of RBCs through secretion of EPO
2. Increase secretion of renin from juxtaglomerular complex
What structure in the kidneys allows for the ability to form concentrated urine?
1. The collecting duct (depends on the presence of ADH)
What happens to the concentration of urine when ADH is present and absent?
1. ADH present: Highly concentrated urine
ADH causes aquaporins to be inserted in plasma membrane of DCT and collecting duct
Increases permeability of membrane to water for reabsorption
2. ADH absent: Highly diluted urine
Absence of ADH prevents water reabsorption in DCT and collecting ducts
All fluid reaching DCT is lost in urine
What are the actions of angiotensin converting enzyme (ACE)?
1.Converts angiotensin I to angiotensin II
2. Angiotensin II: stimulates adrenal production of aldosterone (Na+ retention and K+ loss)
3. Stimulates secretion of ADH
4. Stimulates thirst
5. Triggers constriction of arterioles
What ions/molecules undergo tubular secretion?
What is the kidney's response to increased levels of aldosterone?
1. Promotes Na+ retention
2. Promotes K+ loss
Where on the nephron does most of the nutrient reabsorption occur?
1. 99% of nutrient reabsorption occurs in the PCT
What areas of the nephron are most sensitive to ADH?
2. Collecting duct
Where on the nephron does most of the tubular secretion occur?
Where on the nephron does obligatory water reabsorption occur? Where does facultative water reabsorption occur?
1. Obligatory reabsorption: PCT and descending loop of Henle (mostly descending loop)
2. Facultative reabsorption: DCT and collecting duct (requires presence of ADH)