Physiology

Question 1

Two types of nephrons and their functions

Answer 1

1. Superficial (cortical) nephrons: Reabsorption and secretion
2. Juxtamedullary nephrons: Concentration of urine

Question 2

Bowman’s/Glomerular capsule general function

Answer 2

Site of filtration

Question 3

Proximal convoluted tubule (PCT) general function

Answer 3

Reabsorption of water, electrolytes, glucose.

Secretion

Question 4

Loop of Henle general function

Answer 4

Form osmotic gradient for water reabsorption

Question 5

Distal convoluted tubules and collecting ducts general functions

Answer 5

Fine tuning of reabsorption of water, ions, urea

Question 6

Basic process of urine formation (4 steps)

Answer 6

1. Glomerular filtration
2. Reabsorption
3. Secretion
4. Excretion

Question 7

Describe reabsorption (general)

Answer 7

Fluid transported from tubular lumen into peritubular capillaries
99% of filtrate is reabsorbed to compensate for high glomerular filtration rate (GFR) of 180L/day

Question 8

Describe the process of secretion (basic)

Answer 8

Transfer of metabolic anions and cations from peritubular capillaries into tubule

Question 9

Describe the process of excretion (general)

Answer 9

Unwanted substances (urea, uric acid, drugs, chemicals) and excess electrolytes exit through collecting ducts and into ureteric/urethral passages

Question 10

Glomerular filtration barrier filters on basis of both ____ and _____ of proteins

Answer 10

Size and negative charge

Question 11

What are the functions of glomerular slit diaphragms

Answer 11

Nephrin proteins link neighboring podocyte feet. Pores permit passage of small molecules to medium sized proteins.

Question 12

Describe nephrotic syndrome proteinuria (pathophysiology)

Answer 12

Low GFR and excess excretion of proteins

Proteinuria due to cell detachment or apoptosis of podocytes.
Fewer intracellular spaces decrease GFR. Large pores between hypertrophied podocytes generates significant loss of proteins.

Question 13

Symptoms of nephrotic syndrome proteinuria

Answer 13

Frothy urine, edema, CNS problems, anorexia, malaise, abdominal pain

Question 14

PCT reabsorbs ___ of the 180L/day filtered

Answer 14

2/3 or 60-80% (130 L/day)

Question 15

All reabsorption depends on ____ pumps generating a ____ concentration gradient

Answer 15

Na/K pumps

Na concentration gradient

Question 16

Glucose, galactose, fructose, amino acids, acetate, water soluble vitamins, etc. are all cotransported with _____ during reabsorption

Answer 16

Na+

Question 17

With increases in filtered glucose, the capacity of tubule reabsorption reaches a plateau called _____ _____, where SGLTs are saturated, limiting further reabsorption. What pathology is this associated with?

Answer 17

Transport Maximum (Tmax)

Diabetes mellitus

Question 18

__-__% of protein is filtered, then reabsorbed into the ______

Answer 18

1-3%

PCT

Question 19

Most organic ions and drugs are ____ bound, not filtered, and secreted into the _____

Answer 19

Protein bound

PCT

Question 20

What pathology is inflammation of tubules and interstitium?

Answer 20

Tubulointerstitial nephritis 
(E.g. UTI, pyelonephritis)

Question 21

What pathologies are associated with ischemic or toxic injury to the tubules

Answer 21

Acute tubular injury, acute kidney injury

Question 22

How much glucose is in the plasma clearance of a healthy individual?

Answer 22

0ml/min

Question 23

Blood osmolarity is ____ related to the urine concentration

Answer 23

Inversely

Question 24

Low levels of ADH causes (more/less) urine that is (pale/dark)

Answer 24

Low ADH = more urine, pale

Question 25

Nausea, nicotine, and morphine (stimulate/inhibit) ADH release

Answer 25

Stimulate

Question 26

Alcohol (stimulates/inhibits) ADH release

Answer 26

Inhibits

Question 27

Blood Volume: What condition is associated with dehydration, vomiting, hemorrhage, excessive perspiration, diuretics, or inadequate fluid intake

Answer 27

Hypovolemia

Question 28

Blood Volume: What condition is associated with excess salt intake

Answer 28

Hypervolemia

Question 29

5-10% blood volume changes are sensed by __________ in cardiac atria, right ventricle, large pulmonary vessels, aortic arch and carotid sinus. These sensors generate responses mostly with ____ and sympathetic activity

Answer 29

5-10% blood volume changes are sensed by ( BARORECEPTORS ) in cardiac atria, right ventricle, large pulmonary vessels, aortic arch and carotid sinus. These sensors generate responses mostly with ( ADH ) and sympathetic activity

Question 30

Na+ excretion is regulated by 2 primary mechanisms:

Answer 30

GFR and Reabsorption of Na+/water

Question 31

Hypovolemia: This condition is corrected by neuroendocrine factors that (increase/decrease) reabsorption and (increase/decrease) excretion in response to a drop in volume/pressure.

Answer 31

Hypovolemia: This condition is corrected by neuroendocrine factors that ( INCREASE ) reabsorption and ( DECREASE ) excretion in response to a drop in volume/pressure.

Question 32

Hypovolemia: Which (4) neuroendocrine factors increase reabsorption and decrease excretion in response to a drop in volume/pressure

Answer 32

Angiotensin II Aldosterone Sympathetic nervous system ADH

Question 33

Thirst is induced by what peptide hormone?

Answer 33

Angiotensin II

Question 34

A drop in blood pressure in afferent arterioles triggers _____ release from JGA cells

Answer 34

Renin

Question 35

Renin converts angiotensinogen into _______

Answer 35

Renin converts angiotensinogen into ( Angiotensin I )

Question 36

Angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II. What are the functions of angiotensin II

Answer 36

Stimulate renal reabsorption (directly and indirectly via aldosterone and ADH) General vasoconstriction Increases sympathetic activity

Question 37

Explain how ACE inhibitors work

Answer 37

Inhibit conversion of Angiotensin I to Angiotensin II which causes a reduction in: - Na+ and water reabsorption from proximal/distal tubules - Aldosterone and ADH release More excretion of salt and water = lower blood pressure

Question 38

Aldosterone actions

Answer 38

Regulates Na+ reabsorption in distal tubule and collecting ducts Upregulates Na/K ATPases, Na+ channels (ENaC) and ATP levels in principal cells of distal tubule and collecting ducts Increases reabsorption of Na+ (and water osmotically) to restore volume Increases K+ secretion

Question 39

What is the RAAS System

Answer 39

Renin Angiotensin II Aldosterone Sympathetic

Question 40

Congestive heart failure and renovascular hypertension (renal artery stenosis) inappropriately stimulate a correction for which condition

Answer 40

Hypovolemia