Physiology lecture Flashcards

1
Q

renal artery–> segmental artery –> ?

A

interlobar artery

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2
Q

the interloper arteries are connected by:

A

arcuate arteries

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3
Q

the ______ veins are the collecting vessel of the nephron capillary system

A

interlobar

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4
Q
  1. high blood flow

2. 2 capillary beds

A

renal blood flow

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5
Q

_____% of cardiac output goes to the kidneys

A

21

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6
Q

high hydrostatic pressure in

A

glomerular capillary

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7
Q

low hydrostatic pressure in

A

peritubular capillaries

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8
Q
  • filtration
  • reabsorption
  • secretion
  • excretion
A

4 main processes of renal physiology

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9
Q
  • first step in urine formation
  • bulk transport of fluid from blood to kidney tubule
  • result of hydraulic pressure
  • GFR = 180 L/day
A

Filtration

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10
Q
  • process of returning filtered material to bloodstream
  • 99% of what is filtered is reabsorbed
  • may involve transport proteins
A

Reabsorption

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11
Q

Is glucose normally totally reabsorbed?

A

YES

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12
Q
  • material added to lumen of kidney tubule from blood

* active transport (usually) of toxins and foreign substances (saccharine, penicillin)

A

Secretion

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13
Q

*loss of fluid from body in form of urine

A

Excretion

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14
Q

(Amount filtered + amount secreted) - amount reabsorbed =?

A

Amount of solute excreted

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15
Q

Occurs as fluids move across the glomerular capillary in response to glomerular hydrostatic pressure

A

glomerular filtration

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16
Q
  • blood enters glomerular capillary
  • filters out of renal corpuscle
  • large proteins and cells stay behind
  • everything else is filtered into nephron
  • glomerular filtrate
  • plasma like fluid in glomerulus
A

glomerular filtration

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17
Q
  1. molecular weight

2. charges of the molecule

A

factors that determine glomerular filterability

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18
Q

Mechanism: Bulk flow
Direction of movement : From glomerular capillaries to capsule space
Driving force: Pressure gradient (net filtration pressure, NFP)

A

glomerular filtration

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19
Q

Types of pressure:
Favoring Force: Capillary Blood Pressure (BP) Opposing Force: Blood colloid osmotic pressure(COP) and Capsule Pressure (CP)

A

Glomerular filtration

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20
Q

Amount of filtrate produced in the kidneys each minute.

**125mL/min = 180L/day

A

GFR

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21
Q

what does increased renal blood flow do to GFR?

A

increases GFR

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22
Q

what does increased plasma protein do to GFR?

A

increase GFR, causes edema

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23
Q

what does hemorrhage to do GFR?

A

decreases GFR (bc decreased capillary BP)

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24
Q
  1. Renal Autoregulation
  2. Neural regulation
  3. Hormonal regulation
A

Regulate GFR

*all adjust renal blood pressure and resulting blood flow

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25
Q

Sympathetic nerve fibers innervate afferent and efferent arteriole
Normally sympathetic stimulation is low but can increase during hemorrhage and exercise
Vasoconstriction occurs as a result which conserves blood volume(hemorrhage)and permits greater blood flow to other body parts(exercise)

A

Neural regulation of GFR

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26
Q

Several hormones contribute to GFR regulation

  • Angiotensin II. Produced from Renin, released by JGA cells is a potent vasoconstrictor. Reduces GFR
  • ANP(released by atria when stretched) increases GFR by increasing capillary surface area available for filtration
  • NO
  • Endothelin
  • Prostaglandin E2
A

Hormonal regulation of GFR

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27
Q

If a substance is filtered but neither reabsorbed nor secreted, then the amount present in urine is its…..

A

plasma clearance

*amount in plasma cleared/min by glomerulus

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28
Q

125ml of plasma is cleared/min in glomerulus, which is about how many L per day?

A

180L/day

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29
Q
Freely filterable at glomerulus
Does not bind to plasma proteins
Biologically inert
Non-toxic, neither synthesized nor metabolized in kidney
Neither absorbed nor secreted
Does not alter renal function
Can be accurately quantified
Low concentrations are enough (10-20 mg/100 ml plasma)
A

Inulin

*can measure GFR

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30
Q

End product of muscle creatine metabolism
Used in clinical setting to measure GFR but less accurate than inulin method
Small amount secrete from the tubule

A

Creatinine

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31
Q

Transcellular pathway

Paracellular transport

A

2 pathways of absorption

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32
Q
  1. Primary Active Transport
  2. Secondary Active Transport
  3. Pinocytosis
  4. Passive Transport
A

Mechanisms of transport

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33
Q

Some parts of the tubule, especially the proximal tubule, reabsorb large molecules such as proteins by…

A

pinocytosis

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34
Q

Sodium, water and chloride reabsorption in proximal tubule, including….

A
  1. proximal convoluted tubule

2. thick descending loop

35
Q

Sodium, water and chloride are reabsorbed in the…

A

proximal tubule

36
Q

proximal tubule REABSORBS about __% of filtered sodium, chloride, bicarb and potassium.
*also reabsorbs almost all of the filtered glucose and amino acids

A

65%

37
Q

Proximal tubule ______ organic acids, bases and hydrogen ions into tubular lumen

A

secretes

38
Q

major vehicle for reabsorption of sodium, chloride and water

A

Soidum-potassium ATPase

39
Q

in the first half of the PROXIMAL tubule, Na+ is reabsorbed by co-transport along with..

A

Glucose
AAs
other solutes

40
Q

in the second half of the PROXIMAL tubule, sodium is reabsorbed mainly with…

A

Cl-

41
Q

The second half of the proximal tubule has a relatively ____ concentration of chloride compared with the early proximal tubule

A

HIGH

140 mEq/L vs 105 mEq/L

42
Q

In the second half of the proximal tubule, the higher chloride concentration favors the _____ of this ion from the tubule lumen through the intercellular junctions into the renal interstitial fluid.

A

diffusion

43
Q

3 functionally distinct segments of Loop of Henle

A
  1. thin descending
  2. thin ascending
  3. thick ascending
44
Q

Glucose is reabsorbed along with Na+ in the early portion of the

A

proximal tubule

45
Q

Glucose is typical of substances removed from the urine by secondary

A

active transport

46
Q

The amount of glucose reabsorbed is proportionate to the amount ______

A

filtered

47
Q

is the plasma level at which the glucose first appears in the urine.

A

renal threshold for glucose

48
Q

The actual renal threshold for glucose is about 200 mg/dL of arterial plasma, which corresponds to a venous level of about

A

180 mg/dL

49
Q

Hydrogen secretion through secondary

A

active transport

50
Q

Secretion occurs mainly at the proximal tubules, loop of Henle, and early distal tubule

A

H+ secretion (via secondary active transport)

*more than 90% of HCO3 is passively reabsorbed in this manner

51
Q

Beginning in the late distal tubules and continuing through the reminder of the tubular system

  • It occurs at the luminal membrane of the tubular cell
A

Primary active transport

52
Q

Hydrogen ions are transported directly by…

A

hydrogen transporting ATPase

53
Q
  • accounts for only about 5 percent of the total hydrogen ion secreted
  • important in forming a maximally acidic urine
  • hydrogen ion concentration can be increased as much as 900-fold in the collecting tubules
  • decreases the pH of the tubular fluid to about 4.5, which is the lower limit of pH that can be achieved in normal kidneys
A

Hydrogen secreted through proton pump

54
Q

Excretion of Excess Hydrogen Ions and Generation of New Bicarbonate by the…

A

ammonia buffer system

55
Q

Calcium is both filtered and reabsorbed in the kidneys but not

A

secreted

56
Q

Only about 50 per cent of the plasma calcium is

A

ionized

*remainder being bound to plasma proteins

57
Q

Parathyroid hormone (PTH) _____ calcium reabsorption in the thick ascending Loop of Henle and distal tubules

A

increases

58
Q

PTH ______ urinary excretion of calcium

A

reduces

59
Q

When there is excess water in the body and body fluid osmolarity is reduced, the kidney can excrete urine with an osmolarity as low as __ mOsm/liter, a concentration that is only about one sixth the osmolarity of normal extracellular fluid

A

50

60
Q

when there is a deficit of water and extracellular fluid osmolarity is high, the kidney can excrete urine with a concentration of about _______ mOsm/liter

A

1200-1400

61
Q

regulates the permeability of the distal tubules and collecting ducts to water

A

ADH

62
Q

a high osmolarity of the renal medullary interstitial fluid, which provides the osmotic gradient necessary for water reabsorption to occur in the presence of high level of

A

ADH

63
Q

loop of henle
DCT
collecting duct

..all impermeable to?

A

Urea

64
Q

Whether the water actually leaves the collecting duct (by osmosis) is determined by

A

ADH

65
Q

in the hypothalamus detect the low levels of water (high osmolarity), so the hypothalamus sends an impulse to the pituitary gland which releases ADH into the bloodstream.

A

Osmoreceptors

66
Q

ADH makes the wall of the collecting duct more permeable to

A

water

  • Therefore, when ADH is present more water is reabsorbed and less is excreted.
67
Q

Using sodium and other solutes.
Water follows solute to the interstitial fluid (transcellular and paracellular pathway).
Largely influenced by sodium reabsorption

A

Obligatory water resorption

68
Q

Occurs mostly in collecting ducts
Through the water poles (channel)
Regulated by the ADH

A

Facultative (selective) water resorption

69
Q

Nerves from the renal plexus (sympathetic nerve) of the autonomic nervous system enter kidney at the

A

hilus

70
Q

Sensory nerves located in the renal pelvic wall are activated by stretch of the renal pelvic wall (which may occur during diuresis or ureteral spasm/occlusion).

A

renorenal reflex

71
Q

Activation of these nerves leads to an increase in afferent renal nerve activity, which causes a decrease in efferent renal nerve activity and an increase in urine flow rate and urinary sodium excretion

A

Renorenal reflex

72
Q
  1. ADH
  2. aldosterone
  3. ANP
A

humoral regulation of kidneys

73
Q

retention of water is controlled by…

A

ADH

74
Q

Decrease in Blood Volume
Decrease in Blood Pressure
Increase in extracellular fluid (ECF) Osmolarity

A

stimulates ADH release

75
Q

Sodium balance is controlled by…

A

Aldosterone

76
Q

Steroid hormone
Synthesized in Adrenal Cortex
Causes resorption of Na+ in DCT & CD
Also, K+ secretion

A

Aldosterone

77
Q

The primary site of aldosterone action is on the principal cells of the cortical…

A

collecting duct

78
Q

The net effect of ______ is to make the kidneys retain Na+, water resorption and K+ secretion

A

aldosterone

79
Q

The mechanism of ______ is stimulating the Na+K+ ATPase pump on the basolateral side of the cortical collecting tubule membrane.

A

aldosterone

80
Q

is released by atrium in response to atrial stretching due to increased blood volume

A

ANP

81
Q
  • inhibits Na+ and water resorption, also inhibits ADH secretion
  • promotes increased sodium excretion (natriuresis) and water excretion (diuresis) in urine
A

ANP

82
Q

The bladder fills progressively until the tension in its wall rises above a threshold level, and then
A nervous reflex called the micturition reflex occurs that empties the bladder.

A

2 processes of micturition

83
Q

The _____ reflex is an automatic spinal cord reflex; however, it can be inhibited or facilitated by centers in the brainstem and cerebral cortex.

A

micturition

84
Q

Decline in the number of functional nephrons
Reduction of GFR
Reduced sensitivity to ADH
Problems with the micturition reflex

A

changes with aging