Renal Physiology and Renal Function Tests (1)

Question 1

Which of the following parts of the nephron acts a sieve?
a) DCT
b) PCT
c) Glomerulus
d) Loop of Henle

Answer 1

c) Glomerulus

Question 2

Each kidney contains approximately 1 to 1.5 million functional units called

• Basic functional unit of the kidney
• When the kidney filters the blood, the filtrate will go to the bowman’s capsule. The filtrate will stay here

Answer 2

nephrons

Question 3

two types of nephrons

Answer 3

Cortical nephrons and Juxtamedullary nephrons

Question 4

• make up approximately 85% of nephrons, are situated primarily in the cortex of the kidney.
• They are responsible primarily for removal of waste products and reabsorption of nutrients

Answer 4

Cortical nephrons

Question 5

longer loops of Henle that extend deep into the medulla of the kidney.

• Their primary function is concentration of the urine.

Answer 5

Juxtamedullary nephrons

Question 6

What is inside the PCT, blood or filtrate?

Answer 6

Filtrate

Question 7

What is the inside afferent arteriole, blood or filtrate?

Answer 7

Blood

Question 8

Total renal blood flow

Answer 8

1200 mL/min

Question 9

Before returning to the renal vein, blood from the efferent arteriole enters the _____and flows slowly through the cortex and medulla of the kidney
close to the tubules.

Answer 9

peritubular capillaries and the vasa recta

Question 10

• Innermost layer
• Lined by: Endothelial cells
• Contain numerous pores (fenestrae)

Answer 10

Capillary wall membrane

Question 11

• <70,000 MW (66,000)
• negatively charged, the proteins are negatively charged as well when in contact with one another they will
  repel.

Answer 11

Glomerular basement membrane (basal lamina)

Question 12

• Slit membranes prevent filtration of proteins

Answer 12

Visceral epithelium (podocytes)

Question 13

• acts as a filtration barrier.
• Another reason why proteins can’t go out is because of the outermost layer of the capillary membrane which is formed
  by the
• CONTAINS SHIELD OF NEGATIVITY ,

Answer 13

PODOCYTES

Question 14

what are the three GLOMERULAR FILTRATION (layers)

Answer 14

1. Capillary wall membrane
2. Glomerular basement membrane (basal lamina)
3. Visceral epithelium (podocytes)

Question 15

Pressure that forces the fluid outside a vessel.

Answer 15

Hydrostatic pressure

Question 16

Oncotic pressure

Answer 16

Pressure that maintains the fluid inside the vessel

Question 17

• Increased hydrostatic pressure in the glomerular capillary
• Increased GFR

Answer 17

Constriction of the efferent arteriole

Question 18

• Decreased hydrostatic pressure in the glomerular capillary
• Decreased GFR

Answer 18

Constriction of the afferent arteriole

Question 19

Normal GF

Answer 19

120/min

Question 20

• Must pass through three glomerular filtration barrier cellular layers

Answer 20

Plasma filtrate

Question 21

by containing pores and
are referred to as______
- increase capillary permeability but do not allow the passage of large
molecules and blood cells.

Answer 21

fenestrated endothelium

Question 22

What contains the barrier that repels molecules with a negative charge even through they are small enough to pass through the three layers of the barrier.

• It is very important because it is the place where albumin ( primary
  protein associated with renal disease )
• has a negative charge and
  is repelled

Answer 22

Shield of negativity

Question 23

When blood pressure drops prevent a marked decrease in blood flowing through the kidney
- It prevents an increase in the blood level of toxic waste products.

Answer 23

Dilation or action of the afferent arterioles and constriction or pressure of the efferent arterioles

Question 24

increase in blood pressure results in ______ to prevent overfiltration or damage to the glomerulus

Answer 24

constriction of the afferent arterioles

Question 25

- Triggering factor or stimulant: l - Decreases water retention within the circulatory system - resulting in a decreased overall blood volume and subsequent decrease in blood pressure

Answer 25

Low plasma sodium

Question 26

low plasma pressure and low plasma sodium. This will be sensed by the_____ - an enzyme produced by the juxtaglomerular cells, is secreted and reacts with the bloodborne substrate angiotensinogen to produce the inert hormone angiotensin I.

Answer 26

Renin

Question 27

This will be sensed by the _______ which will trigger the juxtaglomerular cells to release renin

Answer 27

Macula densa

Question 28

After the renin secretion, angiotensinogen will be released by the liver and be converted to______ - which is inactivated or non-functional.

Answer 28

angiotensin I

Question 29

If you already have angiotensin I you need an enzyme which is the_____ - released by the lungs.

Answer 29

angiotensin converting enzyme (ACE)

Question 30

When we have Angiotensin

Answer 30

blood flow start to normalize

Question 31

will promote vasoconstriction (constriction of blood vessel) which will normalize the flow of blood and blood pressure

Answer 31

Angiotensin II

Question 32

Angiotensin II will directly act on the PCT to reabsorb sodium and will activate ______ will promote sodium reabsorption in the DCT (indirectly) and paired with sodium reabsorption is water reabsorption.

Answer 32

aldosterone

Question 33

* Dilates (widen) the afferent arteriole * Constricts (hinihigpitan) the efferent Arteriole * Stimulates PCT reabsorption of sodium * Triggers the release of “aldosterone” (Na retaining hormone) from the adrenal cortex * Triggers ADH release by the hypothalamus

Answer 33

ACTIONS OF THE ANGIOTENSIN II

Question 34

* Specific Gravity: 1.008-1.010 * pH: 7.4 * GFR= 120ml/min

Answer 34

GLUMERULAR FILTRATE

Question 35

: plasma concentration of a substance at which active transport stops and increased amounts are excreted in the urine

Answer 35

Renal threshold

Question 36

Glucose renal threshold

Answer 36

160 to 180 mg/dL

Question 37

Are the glomerular filtrate, filtrate and urine the same?

Answer 37

No. Filtrate still needs to undergo processes before becoming urine

Question 38

* Tubule after Bowman’s capsule * Has urine filtrate

Answer 38

PROXIMAL CONVULUTED TUBULE

Question 39

PROXIMAL CONVULUTED TUBULE Reabsorbs:

Answer 39

- Water - K+ - Amino acids 100% - Na+ 65% - Glucose - Vitamins - HCO3 80-90% - Urea 50% - Chloride

Question 40

Substance combines with carrier protein * Electrochemical energy transfers the substance across the cell membrane

Answer 40

Active Transport

Question 41

Active Transport examples

Answer 41

Glucose - PCT amino acids- PCT chloride - Ascending LH Sodium – PCT and DCT*

Question 42

* Differences in their concentration gradient or electrical potential on opposite sides of the membrane

Answer 42

Passive Transport

Question 43

gradual change in the concentration of solutes in a solution as a function of distance through a solution.

Answer 43

Concentration gradient

Question 44

Passive Transport example

Answer 44

Water Urea: PCT and Ascending LH Sodium: Ascending LH**

Question 45

Important in regulating osmolarity of the medullary interstitial fluid

Answer 45

Loop of henle

Question 46

- Imbedded system in the loop of Henle - Two limbs of the loop of henle has different activity

Answer 46

Countercurrent multiplier system

Question 47

* Water is passively reabsorbed * Permeable to water

Answer 47

Descending limb

Question 48

* Na+ and Cl- are actively and passively reabsorbed * Impermeable to water (no reabsorption of water)

Answer 48

Ascending limb

Question 49

Where do the final concentration of the filtrate takes place?

Answer 49

Distal convoluted tubule and collecting duct.

Question 50

antidiuretic hormone [ADH]).

Answer 50

vasopressin

Question 51

increases permeability; increased reabsorption of water; low-volume urine

Answer 51

High ADH

Question 52

determined by the state of body hydration.

Answer 52

Production of ADH

Question 53

* Passage of substances from the blood in the peritubularcapillaries to the tubular filtrate * Eliminates of waste products not filtered by the glomerulus * Regulates of the acid-base balance

Answer 53

TUBULAR SECRETION

Question 54

final process or step in urine formation

Answer 54

Secretion

Question 55

substances in the capillaries will be transported to the renal tubules

Answer 55

Tubular secretion

Question 56

alkaline urine; the tubules cannot produce the hydrogen ion.

Answer 56

Renal tubular acidosis

Question 57

Blood must buffer and eliminate excess acids - Secretion of hydrogen ions causes reabsorption of bicarbonates

Answer 57

Acid –Base balance

Question 58

reflects the ability of the kidney to maintain normal hydrogen ion concentration in plasma and extracellular fluid

Answer 58

pH-

Question 59

* H+ ions are buffered by phosphate or ammonia and excreted into the urine in the form of:

Answer 59

- Ammonium ions - Dihydrogen phosphate - Weak organic acids

Question 60

Each time a H+ ion is secreted into the renal tubule, _____ are absorbed from the tubule

Answer 60

a sodium (Na+) and bicarbonate ion

Question 61

Nephron: PCT * Secretes:

Answer 61

Creatinine (minute), Urea, H+, NH4

Question 62

Filtration

Answer 62

Glomerulus

Question 63

(DCT, PCT Loop of Henle) - Reabsorption and secretion

Answer 63

Tubules

Question 64

Major reabsorption occurs

Answer 64

PCT

Question 65

Exchanges of water and salts

Answer 65

Loop of Henle