Renal Structure and Function

Question 1

Which metabolic waste products are excreted by the kidneys?

Answer 1

• Urea
• Uric acid
• Creatinine
• Bilirubin

Question 2

How is urea produced?

Answer 2

Proteins -> Amino acids-> NH2 removed-> forms ammonia-> liver convert ammonia to urea

Question 3

Uric acid is produced from _________ catabolism.

Answer 3

Nucleic acid

Question 4

Creatinine is produced from _______ catabolism.

Answer 4

Creatine phosphate

Question 5

Azotemia

Answer 5

Nitrogenous wastes in blood

Question 6

Uremia

Answer 6

Toxic effects as wastes accumulate

Question 7

There are two types of bilirubin. What are they and where are they located?

Answer 7

• Unconjugated (indirect) bilirubin
  
  • ​Created from rbc breakdown
  • Travels in the blood to the liver
• ​Conjugated (direct) bilirubin
  
  • ​Bilirubin once it reaches the liver
  • Undergoes a chemical change
  • Moves to the intestines before being removed through your stool

Question 8

Normal total bilirubin

Answer 8

• Under 18: 1 mg/dl
• Over 18: 1.2 mg/dl
• In urine: <1 mg/dl

NOTE: Normal results for conjugated bilirubin should be less thab 0.3 mg/dl

Question 9

Normal serum creatinine concentrate

Answer 9

0.6 to 1.2 mg/dL

Question 10

Normal BUN concentration

Answer 10

8 to 25 mg/dL

Question 11

BUN to creatinine ratio is elevated in ____________.

Answer 11

Preranal acute kidney injury

NOTE: An elevated level would be a ratio greater than 20:1

Question 12

Pre-Renal vs. Post-renal acute kidney injury

Answer 12

• Pre-Renal
  
  • ​Inadequate Perfusion
    
    • ​Not enough blood at sufficient pressure to allow filtering
• Renal
  
  • ​Cellular Damage/Intristic
    
    • ​Damage to the cells that make filtering mechanism possible
• Post- Renal​
  
  • ​Obstruction
    
    • ​Urine unable to drain adequately-system “backed up”

Question 13

Which chemicals are excreted from the kidneys?

Answer 13

• Pesticides
• Food additives
• Toxins
• Drugs

Question 14

What hormones are produced in the kidney?

Answer 14

• Renal erythropoetic factor
• 1,25 dihydroxycholecalciferol (Vitamin D)
• Renin

Question 15

What hormones are metabolized and excreted by the kidney?

Answer 15

• Most peptide hormones

Examples: Insulin, angiotensin II, etc.

Question 16

How do the kidneys regulate erythrocyte production?

Answer 16

1. Decreased O2 delivery to kidney
2. Increased erythropoetin
3. Increased erythrocyte production in kindeys

Question 17

The kidneys produce the ___ (active/inactive) form of vitamin D.

Answer 17

Active

*1,25 dihydroxy vittamin D3

Question 18

Vitam D3 is important in ___ and _____ metabolism.

Answer 18

Phospahate; calcium

Question 19

How do kidneys regulate acid- base balance?

Answer 19

• Excrete acids
• Regulate body fluid buffers

NOTE: KIdneys are the only means of excreting non-volatile acids

Question 20

Kidneys role in gluconeogenesis

Answer 20

Kidneys synthesize glucose from precursors during prolonged fasting

Question 21

How do kidneys regulate arterial pressure?

Answer 21

Endocrine organ

• ​Renin-angiotensin system
• Prostoglandins
• Kallikrein-kinin system

Control of extracellular fluid volume

Question 22

Nephron Tubular Segments

Answer 22

Question 23

Function of proximal convoluted tubule

Answer 23

Reabsorption of water, ions, and all organic nutrients

Question 24

Function of distal convoluted tubule

Answer 24

Secretion of ions, acids, drugs, toxins

NOTE: Distal convoluted tubules also have reabsorption ability of water, sodium ions, and calcium ions, under hormonal control

Question 25

Function of collecting duct

Answer 25

Variable reabsorption of water and reabsorption or secretion of sodium, potassium, hydrogen, and bicarbonate ions

Question 26

Function of renal corpuscle

Answer 26

Production of filtrate

Question 27

Function of Loop of Henle

Answer 27

* Further reabsorption of water (descending limb) and both sodium and chloride (ascending limb)

Question 28

Function of papillary duct

Answer 28

Delivery of urine to minor calyx

Question 29

What are the basic mechanisms of urine formation?

Answer 29

1. Filtration 2. Reabsorption 3. Secretion 4. Excretion

Question 30

Distinguish between the variability and selectivity of filtration, reabsorption, and secretion.

Answer 30

**Filtration** * Somewhat variable * Not selective **Reabsorption** * Highly variable * Selective **Secretion** * Highly variable

Question 31

Renal Handling of Different Substances

Answer 31

Question 32

Renal Handling of Water and Solutes

Answer 32

**NOTE:** Glomerular filtration rate decreases with age, which can lead to varies stages of kidney disease

Question 33

What affect can NSAIDs have on glomerular filtration rate?

Answer 33

**Decrease** * NSAIDs block the protective prostaglandin effect. **GFR is not maintained**. Acute kidney injury can ensue **NOTE:** In the absence of NSAIDs, in the setting of decreased effective circulating volume, the afferent arterioles vasodilate via prostaglandin whileefferent arterioles vasoconstrict. GFR is maintained

Question 34

\_\_\_\_\_\_\_\_\_\_ are the primary regulators of the extracellular fluid volume.

Answer 34

Kidneys

Question 35

How do the kidneys control blood pressure?

Answer 35

By increasing the ECF **NOTE:** Kidneys maintain blood plessure by keeping fluid balance and metabolite balance

Question 36

Createnine is used to measure\_\_\_\_\_\_\_\_\_\_.

Answer 36

Glomerular filtration rate

Question 37

What factors to can lead to a decrease in perfusion?

Answer 37

* Decrease in blood pressure * Increase in resistance for efferent arteriole

Question 38

What are the major stimuli for the renin-angiotensin system?

Answer 38

* Low blood pressure * Decrease in salt * Hyperkalemia

Question 39

Mechanism by which low salt leads to an increased production of aldosterone

Answer 39

1. Low salt stimulates renin 2. Renin produces angiotensin I 3. That is converted to angiotensin II 4. Angiotensin II stimulates the adrenal cortex to release aldosterone 5. Aldosterone acts of Na-K- ATPase that is on the basal lateral membrane to promote sodium reabsorption and potassium secretion

Question 40

The cortex contains ______ of the blood supply in the kidney.

Answer 40

80%

Question 41

Outside of the colelcting duct is the \_\_\_\_\_\_\_, which serves as a reservoir for the filtration to travel into the pelvis and then into the ureters.

Answer 41

Minor calyx

Question 42

What the two capillary beds of the kidneys and what takes place in each?

Answer 42

* **Glomeruli capillary** * **​**Where filtration takes place * **Peritubular capillary** * **​**Where reabsorption and secretion occurs **NOTE:** The afferent arteriole brings blood into glomeruli capillary where it is filtered. The remaining blood from the glomerular capillary and goes back to efferent arteriole and back to circulation

Question 43

Tubular glomerular feedback mechanism

Answer 43

States that the filtrate that travels in the proximal tubule, and loop of henle goes across the macula densa cells. These cells sense sodium concentration and flow rate.

Question 44

Is the proximal tubule considered hypo-osmotic, hyper-osmotic, or iso-osmotic?

Answer 44

Iso-osmotic \*This means that reabsorbing water and electrolytes in similar concentration and the reabsorption of filtrate has the same osmolarity as the plasma