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Semester 4 > deck_17307781 > Flashcards

deck_17307781 Flashcards

1
Q

urinary system maintains homeostasis by regulating the ____ and ____ of blood

A

volume & composition of blood

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2
Q

concentration of urine

A

855–1355 mOsm/L

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3
Q

kidneys excrete ____, especially ____

A

solutes

esp metabolic wastes

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4
Q

E.g. of metabolic wastes

A

Urea

Creatinine

Uric acid

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5
Q

urea

A

Most abundant organic waste

By-product of amino acid breakdown

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6
Q

creatinine

A

By-product of creatine phosphate breakdown in muscles

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7
Q

Uric acid

A

Formed during recycling of nitrogenous bases of RNA

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8
Q

three processes involved in urine formation:

A

1) filtration

2) reabsorption

3) secretion

____

secretion vs filtration?

“Filtration occurs in the glomerulus, while secretion occurs in the proximal and distal convoluted tubules.” (AI)

“secretion is the movement of solutes from the bloodstream into the filtrate.”

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9
Q

filtration

A

blood hydrostatic pressure forces water and solutes across the membranes of the glomerular capillaries into the capsular space

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10
Q

filtration ONLY happens in ____

A

ONLY happens in the glomerulus

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11
Q

The resulting fluid that enters the capsular space is _____

A

the glomerular filtrate

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12
Q

filtration occurs through ___

A

the filtration membrane

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13
Q

filtration membrane consists of

A

1) fenestrations of glomerular endothelial cells (capillaries)

2) basement membrane (collagen fibres & proteoglycans)

3) filtration slit = space between pedicels of podocytes

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14
Q

what is too big to cross the GLOMERULAR (capillary) ENDOTHELIAL CELLS?

A

blood cells & proteins too big too cross

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15
Q

what is too big to cross the BASEMENT MEMBRANE?

A

large negatively charged proteins do not fit

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16
Q

what fits through the filtrations slits

A

water, glucose, vitamins, amino acids, very small plasma proteins, ammonia, urea, & ions fit

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17
Q

NET FILTRATION PRESSURE

(NFP)

A

Glomerular Blood Hydrostatic Pressure (GBHP)

+

Capsular Hydrostatic Pressure (CHP)

+

Blood Colloid Osmotic Pressure (BCOP)

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18
Q

Glomerular Blood Hydrostatic Pressure (GBHP) =

A

55 mmHg

blood pressure in glomerular capillaries

Pro-filtration

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19
Q

Capsular Hydrostatic Pressure (CHP) =

A

15 mmHg

hydrostatic pressure pushing against filtration membrane by fluid already in capsular space

Anti-filtration

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20
Q

Blood Colloid Osmotic Pressure (BCOP) =

A

30 mmHg

osmotic pressure of large proteins pulling water into capillaries

Anti-filtration

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21
Q

so NFP is …

A

(GBHP) – (CHP) – (BCOP)

(55 – 15 – 30)

= 10 mmHg (under normal circumstances)

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22
Q

therefore, NFP dictates …

A

NFP dictates how much will move in which direction

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23
Q

filtration will stop if (for instance) …

A

*** Filtration stops if GBHP drops below 45mmHg

b/c in this example, opposing pressure = 45mmHg

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24
Q

Filtration Fraction (FF)

note two concepts

A

Renal plasma flow (RPF)

Filtration fraction (FF)

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25
Q

Renal plasma flow (RPF) =

A

volume of plasma that moves through the kidneys per unit time

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26
Q

Filtration fraction (FF) =

A

is the fraction of RPF that becomes GLOMERULAR FILTRATE

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27
Q

recall – what is glomerular filtrate?

A

The resulting fluid that enters the capsular space

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28
Q

normal Filtration Fraction (percentage)?

A

Normal FF = 16-20%

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29
Q

what is daily GLOMERULAR FILTRATE (avg)

A

Daily glomerular filtrate = 150L - 180L

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30
Q

what percentage of glomerular filtrate is RETURNED to bloodstream?

therefore, how much urine is actually produced?

A

99% of filtrate is returned to bloodstream

by tubular REABSORPTION

Therefore, 1-2L of urine produced daily

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31
Q

Glomerular Filtration Rate (GFR)

A

amount of filtrate formed per minute in all the renal corpuscles of both kidneys

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32
Q

normal glomerular filtration rate

A

Normal is 105-120 ml/min

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33
Q

Glomerular Filtration rate is DIRECTLY proportional to ____

A

Net Filtration Pressure
(NFP)

(Increased Net Filtration Pressure (NFP) INCREASES Glomerular Filtration Rate (GFR) )

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34
Q

how is Kidney function tested?

A

via eGFR (estimated)

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35
Q

what values indicate kidney disease vs kidney failure

A

An eGFR of <90 usually indicates kidney disease

An eGFR of <15 usually indicates kidney failure

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36
Q

what is the problem with GFR getting too high

A

If GFR ever gets too high, needed substances pass so quickly through renal tubules that they can’t be reabsorbed & are lost in urine

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37
Q

what is the problem with GFR getting too low?

A

If GFR ever gets too low, metabolic wastes will not get filtered from the blood and into the renal tubules

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38
Q

what THREE regulatory mechanisms are in place to maintain GFR?

A

1) Renal autoregulation

2) Neural regulation

3) Hormonal regulation

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39
Q

1) RENAL AUTOREGULATION (to maintain GFR)

involves TWO important structures …

A

Mesangial cells

Juxtaglomerular Apparatus (JGA)

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40
Q

renal autoregulation involves TWO important mechanisms

A

Myogenic mechanism (faster)

Tubuloglomerular feedback (slower)

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41
Q

Mesangial cells (of renal autoregulation, of GFR)

mesangial cells lie between ___

A

Lie between adjacent GLOMERULAR CAPILLARIES

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42
Q

mesangial cells control ____

A

capillary diameter and rate of blood flow

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43
Q

Juxtaglomerular Apparatus (JGA)

(of renal autoregulation, of GFR)

A

a specialized structure where the distal convoluted tubule meets the afferent arteriole

main function is to regulate blood pressure and the filtration rate of the glomerulus

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44
Q

Juxtaglomerular Apparatus (JGA) structures

A

Macula densa

Juxtaglomerular cells (granular cells)

Extraglomerular mesangial cells

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45
Q

macula densa

A

Specialized cells in the DCT

detectÂchanges in tubule NaCl concentration

—> therefore detects changes in GFR

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46
Q

Juxtaglomerular cells (granular cells)

A

Specialized cells in the AFFERENT arteriole

Secrete RENIN in response to low BP

–> + renin = +BP

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47
Q

Extraglomerular mesangial cells

A

can affect blood flow through the arterioles

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48
Q

Myogenic mechanism (faster type of renal autoregulation)

A

stretch receptors in afferent arterioles respond to increased or decreased blood pressure (BP)

Smooth muscle of afferent arteriole constricts or dilates to increase or decrease GFR to what it was previous to BP change

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49
Q

Tubuloglomerular feedback (slower)

A

Uses the juxtaglomerular apparatus

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50
Q

with the tubuloglomerular feedback, when BP is increased, GFR is increased

THEREFORE, in response, in order to DECREASE GFR, the following takes place:

A

macula densa cells (of JGA) detect increased concentration of Na+, Cl-

Macula densa cells release a vasoconstrictor (adenosine)

Afferent arterioles vasoconstrict = DECREASED GFR

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51
Q

with the tubuloglomerular feedback, when BP is decreased, GFR is decreased

THEREFORE, in response, in order to INCREASE GFR, the following takes place:

A

Macula densa cells (of JGA) detect decreased concentration of Na+, Cl-

Macula densa cells release vasodilators (nitric oxide)

Afferent arterioles vasodilate = INCREASED GFR

(Also, signal for juxtaglomerular cells to release RENIN which will work to get BP up (more later))

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52
Q

NEURAL REGULATION of GFR

A

at rest, not much sympathetic ANS stimulation

renal autoregulation prevails

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53
Q

neural autoregulation of GFR during fight-or-flight (stress) response

A

during fight-or-flight, sympathetic ANS fibres release norepinephrine to cause vasoconstriction of afferent arterioles

= DECREASED GFR

(no need to produce urine when in dangerous scenario)

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54
Q

If (overall systemic) blood pressure is very low (MAP < 65 mmHg) what happens to neural regulation of GFR?

A

sympathetic NS is activated

Increases BP systemically to make sure important tissues are perfused

vasoconstriction of afferent arterioles to conserve blood elsewhere = DECREASED GFR

—> Sacrifices GFR

(Also causes release of RENIN)

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55
Q

3) Hormonal Regulation of GFR

(important components)

A

Angiotensin II

ANP (Atrial Natriuretic Peptide)

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56
Q

Angiotensin II

A

Part of RAA system (renin-angiotensin-aldosterone system)

Increased in response to renin (from JGA)

FYI:
(Aim is to get blood pressure up without increasing GFR too much, so it will maintain or slightly increase GFR)

(—> vasoconstrictor = narrow afferent and efferent arterioles)

—> *also increases reabsorption (more later)

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57
Q

ANP (Atrial Natriuretic Peptide)

A

secreted by heart cells when blood in atria stretch walls

relaxes mesangial cells = INCREASES surface area of glomerulus = INCREASES GFR

—> *also limits reabsorption (more later)

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58
Q

REABSORPTION

A

Movement of solutes and water from renal tubules into the blood

(peritubular capillaries or vasa recta)

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59
Q

reabsorption can either be ___ or ___

A

paracellular

or transcellular

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60
Q

transcellular reabsorption utilizes …

A

primary and secondary active transport

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61
Q

primary active transport

A

moves solute across membrane with a pump using ATP (ie. Na+/K+ATPase)

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62
Q

secondary active transport

A

electrochemical gradient causes the movement of 2 ions across membrane; one ion moves with its gradient and other moves against its gradient

symporters: move 2 or more ions in same direction

antiporters: move 2 or more ions in opposite directions

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63
Q

MOST REABSORPTION takes place in

A

Proximal Convoluted Tubule (PCT)

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64
Q

what can get reabsorbed in PCT?

A

> 99 percent of glucose,
amino acids,
other organic nutrients

Sodium,
potassium,
bicarbonate,
magnesium,
phosphate,
sulfate ions

Water (about 108 liters each day)

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65
Q

Glucose Amino Acid Reabsorption from THE PCT

A

Various Na+ symporters in APICAL MEMBRANE reclaim:

—> 100% of filtered glucose & amino acids, HPO42, SO42-, & lactic acid

most use FACILITATED DIFFUSION to cross BASOLATERAL MEMBRANE and flow into interstitial fluid, and then PERITUBULAR CAPILLARIES

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66
Q

except for Na+ which crosses basolateral membrane via ___

A

via sodium-potassium pump (ATPase)

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67
Q

Bicarbonate Reabsorption from THE PCT

A

Antiporters move H+ from cytosol to lumen, and Na+ from lumen to cytosol

supply of H+ maintained by CO2 flowing into cell
—> Recall CO2 + H2O —> H2CO3 —> H+ + HCO3-

(this process also reabsorbs 80-90% of filtered HCO3-)

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68
Q

Water reabsorption from PCT is via

A

Via osmosis (obligatory water reabsorption)

& PARACELLULAR REABSORPTION (passive process through leaky tight junctions)

this is d/t solutes increased of osmolarity of cytosol, interstitial fluid, and then peritubular blood
—> Water follows the solutes

also,
tubule cells in PCT & descending limb of nephron loop have high amount of aquaporins in APICAL & BASOLATERAL membranes

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69
Q

remaining reabsorption from PCT

A

50% of filtered:
—> Cl-
—> urea

variable amount of filtered:
—> Mg2+
—> Ca2+
—> HPO42-

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70
Q

Secretion @ PCT

A

H+ is released into the lumen via Na+/H+ antiporters

H+ secretion controls blood pH

Also, substances eliminated from the body:
—> NH4+ and some medications

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71
Q

OVERVIEW OF reabsorption & secretion @ THE PCT

A

Reabsorption:
100% of filtered glucose, amino acids, HPO42, SO42-, & lactic acid
85-90% of filtered bicarbonate
65% of filtered H2O
65% of filtered sodium, potassium
50% of filtered chloride, urea

Secretion:
Ammonium (NH4+) and some medications

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72
Q

Nephron loop and reabsorption/secretion

why is fluid in nephron loop different from original filtrate

there is LOTS of ____ but VERY LITTLE ____

A

fluid here is quite different from original filtrate b/c glucose, amino acids & other nutrients are removed

enters this part of tubule more slowly d/t less H2O in fluid

Lots of reabsorption, VERY LITTLE TO NO SECRETION

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73
Q

reabsorption @ NEPHRON

what percentage of H2O?

ONLY IN WHICH part of the nephron loop?

A

15% of filtered H2O

in descending limb only

ascending limb impermeable to water

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74
Q

other substances reabsorbed @ nephron loop

A

20-30% of filtered Na+ & K+
35% of filtered Cl-
10-20% of filtered HCO3-
variable Mg2+ & Ca2+

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75
Q

REABSORPTION & SECRETION

(@ EARLY DISTAL CONVOLUTED TUBULE)

Why does fluid (filtrate) begin travelling slowly at this point?

A

Fluid travelling very slowly, as 80% water reabsorbed

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76
Q

what else reabsorbed @ DCT?

A

10-15% of remaining water via osmosis

5% of Na+ & Cl-

PTH acts here to reabsorb Ca2+

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77
Q

secretion @ EARLY DCT

A

none

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78
Q

Late Distal Convoluted Tubule and Collecting Duct

(reabsorption & secretion)

what percentage of water/solutes have been returned to blood at this point?

A

90-95% of water and solutes have been returned to blood

H2O and solute reabsorption & secretion here depend on body’s needs

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79
Q

reabsorption @ LATE DCT involves two cells

A

Principal cells & Intercalated cells

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80
Q

principal cells of late DCT – responsible for …

A

reabsorb Na+ & H2O

(Secrete K+)

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81
Q

intercalated cells of late DCT – responsible for …

A

(reabsorb K+)

reabsorb HCO3- to regulate pH

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82
Q

two hormones involved with increasing blood volume (@ DCT)

A

ADH

Aldosterone

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83
Q

ADH (@ late DCT)

A

ADH stimulates formation of aquaporins to reabsorb H2O

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84
Q

Aldosteron (@ late DCT)

A

stimulates reabsorption of Na+, Cl-, & H2O

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85
Q

Late Distal Convoluted Tubule and Collecting Duct

SECRETION

A

Principal cells: secrete K+

Intercalated cells: secrete H+

Urea

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86
Q

Hormonal Regulation of Tubular Reabsorption & Secretion

A

Many hormones play a role in regulating the amount of solute and water that is reabsorbed or secreted in the tubules

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87
Q

which hormones play a role in regulation of reabsorption & secretion

A

1) Renin-Aldosterone-Angiotensin System (RAAS)

2) Antidiuretic Hormone (ADH)

3) Atrial Natriuretic Peptide (ANP)

4) Parathyroid Hormone (PTH)

5) Calcitonin

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88
Q

1) Renin-Angiotensin-Aldosterone System (RAAS)

A

Angiotensin II
Already discussed: REDUCED GFR via vasoconstriction of afferent arterioles
—>
INCREASED reabsorption of Na+, Cl- and therefore H2O via Na+/H+ antiporters in PCT
—>
stimulates adrenal cortex to release ALDOSTERONE

Aldosterone
acts on principal cells to reabsorb more Na+, Cl-, and therefore H2O

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89
Q

2) Antidiuretic Hormone (ADH)

A

osmoreceptors in hypothalamus respond to low blood volume by stimulating posterior pituitary to release ADH
—>
Also released in response to angiotensin II

principal cells INCREASE number of aquaporins on apical surface to reabsorb more H2O
—>
REDUCED ADH = dilute urine
INCREASED ADH = concentrated urine

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90
Q

3) Atrial Natriuretic Peptide (ANP)

A

atrial cells in heart release ANP in response to increased stretch due to elevated BP

Already discussed: relaxes mesangial cells = INCREASE surface area of glomerulus = INCREASE GFR

inhibits reabsorption of Na+ and therefore H2O in PCT & collecting duct

**(also, suppresses secretion of ADH & aldosterone )

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91
Q

4) Parathyroid Hormone (PTH)

A

REDUCED blood Ca2+ = parathyroid glands release PTH

cells in early DCT INCREASE Ca2+ reabsorption = INCREASED blood Ca2+

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92
Q

5) Calcitonin

A

INCREASED blood Ca2+ = parafollicular cells (C cells) release calcitonin

REDUCED Ca2+ reabsorption in the distal tubule = REDUCED blood Ca2+

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93
Q

TWO TYPES OF WATER REABSORPTION

A

1) Obligatory water reabsorption

2) Facultative water reabsorption

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94
Q

1) Obligatory water reabsorption

A

Occurs in locations where water movements cannot be prevented

Rate cannot be adjusted

Recovers 85 percent of filtrate

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95
Q

where does obligatory water reabsorption take place?

A

PCT and descending limb of nephron loop

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96
Q

2) Facultative water reabsorption

A

Allows precise control of water reabsorption by ADH

Adjusts urine volume by reabsorbing a portion (or all) of the remaining 15 percent of filtrate volume

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97
Q

where does facultative water reabsorption take place?

A

Occurs in the DCT and collecting tubule

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98
Q

NORMAL URINE volume

A

Normal volume is about 1200 mL/day

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99
Q

NORMAL URINE osmotic concentration

A

Normal osmotic concentration of 600 - 1500 mOsm/L

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100
Q

urine values differ …

A

Values differ from person to person and from day to day

(Kidneys alter their function to maintain homeostasis)

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101
Q

The production of dilute urine

A

..

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102
Q

dilute urine is produced in the absence of ____

A

produced in the absence of ADH

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103
Q

No ADH =

A

Err:509

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104
Q

kidneys produce dilute urine b/c …

A

= no aquaporins = less water reabsorption

therefore
—>
urine up to 4X more dilute than blood plasma

(As low as 80 mOsm/L compared to 300 mOsm/L of blood)

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105
Q

Causes of dilute urine

A

Over hydration

Diabetes insipidus (more later)

Renal failure

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106
Q

The production of concentrated urine

produce with ____

A

Concentrated urine is produced in the presence of ADH

kidneys produce concentrated urine b/c large amounts of water are reabsorbed from the tubular fluid into the interstitial fluid

—>
therefore increasing solute concentration of the urine (urine up to 5X more concentrated than blood plasma)

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107
Q

THE COUNTERCURRENT MULTIPLICATION SYSTEM

A

A system in the nephron loop of juxtamedullary nephrons that allows the kidneys to produce concentrated urine

108
Q

countercurrent multiplication system generates ____

enables you to ____

A

generates anÂOSMOTIC GRADIENTÂin the renal interstitial fluid

—> enables you to reabsorb water from the tubular fluid and produce concentrated urine

(So don’t unnecessarily lose water in the urine)

109
Q

nephron loop — thin descending limb

permeable to ____
impermeable to ____

A

permeable to H2O

impermeable to Na+, Cl-, K+

110
Q

juxtamedullary nephrons BV

A

vasa recta

111
Q

nephron loop – THICK ascending limb

A

permeable to Na+, Cl-, K+

Impermeable to H2O

112
Q

how is Na+, Cl-, K+ pumped out of THICK ascending limb?

A

Pumped out of tubule due to Na+-K+-2Cl- cotransporters

113
Q

D/t to the DIFFERENCE in permeability b/w thin/thick limbs, we establish _____ in the _____

A

we establish an osmotic gradient in the renal medulla

114
Q

why is it called the “countercurrent multiplication system”

A

Countercurrent because the thin and thick limbs run in opposite directions to each other

Multiplication because the osmolality of the renal medulla increases or â€multipliesâ€ the deeper you go

115
Q

osmolality vs osmolarity

A

Osmolarity is the number of milliosmoles of solute per liter solution. This differs from osmolality (osm), which is the milliosmoles of solute per kilogram of solution.

116
Q

what does thick ascending limb do?

A

actively pumps Na+, Cl-, and K+ in the interstitial space of the renal medulla

117
Q

what happens to renal medulla in this area (of the thick ascending limb?)

Why?

A

it makes the renal medulla â€saltyâ€ or hypertonic in this area

Because the thick ascending limb is impermeable to water

118
Q

what does salty medulla lead to?

A

This allows for passive water absorption in the thin descending limb (obligatory) and the collecting duct (in the presence of ADH)

119
Q

NOTE WHAT UREA DOES IN COUNTERCURRENT MULTIPLICATION SYSTEM

A

it is reabsorbed in the collecting duct, but secreted in the ascending limb
—>
(Goes back)

“recycledâ€ in a process called urea recycling

120
Q

what is the purpose of urea recycling?

A

Also helps maintain the osmotic gradient in the renal medulla

(Helps reabsorb water passively)

121
Q

Countercurrent exchange

A

is the process by which solutes and water are passively exchanged between the blood of the vasa recta and interstitial fluid of the renal medulla

Helps to reabsorb water without “washing awayâ€ the osmotic gradient we worked so hard to set up

122
Q

the vasa recta is called ____

because ____

A

the vasa recta is called the countercurrent exchanger

b/c the descending and ascending portions also run opposite of each other and they exchange solutes and H2O

123
Q

vasa recta also supply ____ with _____

A

Vasa recta also supply the renal medulla with oxygen and nutrients

124
Q

Pathology

A

..

125
Q

Diabetes Insipidus

A

An inadequate response to ADH

or inadequate production of antidiuretic hormone (ADH)

126
Q

insipidus

A

“lacking flavour or zest”

127
Q

types of diabetes insipidus

A

Central DI (diabetes insipidus)

Nephrogenic DI

128
Q

Central DI

A

inability of the posterior pituitary/hypothalamus to secrete ADH

129
Q

nephrogenic DI

A

defects in ADH receptors

130
Q

DI SSx

A

excretion of large volumes of dilute urine

with resulting dehydration and thirst

131
Q

what happens if DI not treated

A

can experience SSx of dehydration

—> Feeling dizzyÂor lightheaded, nausea, fainting, fatigue

—> Having a dry mouth, lips and eyes

—> Difficulty performing simple mental tasks

132
Q

DI, Epidemiology

what is rate?

Who can it affect? (age)

A

Rare: It affects about 1 in 25,000 people worldwide

People of all ages can develop diabetes insipidus

133
Q

Etiology, central DI

A

Damage to the hypothalamus/posterior pituitary during surgery or due to head injury

Non-functional brain tumours

Genetic mutations

Autoimmune destruction of cells that make ADH

134
Q

nephrogenic DI, etiology

A

medications (lithium, tetracycline)

Inherited genetic mutations

135
Q

Central DI, Tx

A

Desmopressin (synthetic vasopressin or ADH)

136
Q

Nephrogenic DI, Tx

A

Thiazide diuretics (?)

In the absence of ADH (receptors?), these (anti-?)diuretics decrease urinary output by decreasing GFR

137
Q

DI, Px

A

Usually good if managed well and those affected drink enough water

138
Q

LECTURE 3

A

..

139
Q

Normal Urine Composition

A

..

140
Q

normal urine volume

normal urine osmolarity

A

Normal volume is about 1200 milliLiters/day

with an osmotic concentration of 1000 milliOsmole/L

141
Q

what can changes in urine indicate?

A

Changes in urine can be tested and measured to show abnormalities in the urinary system

or abnormalities elsewhere

142
Q

urine water composition

A

95% of total urine volume

143
Q

remaining 5% of urine composition

A

Electrolytes

“Solutes derived from cellular metabolism”

Exogenous substances such as drugs

Small quantities of fatty acids, pigments, enzymes and hormones

144
Q

what are “Solutes derived from cellular metabolism” ?

A

UREA from protein breakdown

CREATININE from creatine phosphate breakdown in mm. fibres

URIC ACID from nucleic acid breakdown

UROBILINOGEN from hemoglobin breakdown

145
Q

Urinalysis

A

sample of urine is taken and individual substances are analyzed

146
Q

what substances are analyzed in Urinalysis

A

RBC

WBC

nitrites

leukocyte esterase

proteins

glucose

among others…

147
Q

what does RBC in urine indicate

A

may indicate infection or kidney stones, but blood could be from other sources

148
Q

what does WBC in urine indicate

A

may indicate infection in urinary tract

149
Q

what does nitrites in urine indicate

A

some bacteria convert nitrates to nitrites, could indicate infection

150
Q

what does leukocyte esterase in urine indicate

A

indicates infection

151
Q

what does proteins in urine indicate

A

may indicate kidney disease

152
Q

what does glucose in urine indicate?

A

may indicate diabetes mellitus

153
Q

blood tests to evaluate kidney function

A

Blood Urea Nitrogen (BUN) (test)

Plasma Creatinine (test)

inulin clearance (test)

PAH clearance (test)

154
Q

Blood Urea Nitrogen (BUN) (test)

A

measures blood nitrogen
—>
(part of urea resulting from the catabolism and deamination of amino acids)

(rises steeply with severe decreases in GFR that can happen with renal disease )

155
Q

Plasma Creatinine (blood test)

A

measures plasma levels of creatinine
—>
(result from the catabolism of creatine phosphate in skeletal muscle cells)

rises steeply with severe decreases in GFR that can happen with renal disease

156
Q

Plasma creatinine blood test is used to estimate ____

A

Used to estimate GFR (eGFR)

157
Q

Inulin Clearance (blood test)

A

measures volume of blood that is cleansed of inulin (per?) unit of time

measures how efficiently the kidneys are removing inulin from the blood

158
Q

high renal clearance

A

High renal clearance = efficient filtration and excretion

159
Q

low renal clearance

A

Low renal clearance = inefficient filtration and excretion

160
Q

what is inulin?

How does it pass through kidneys?

why is it gold standard for eGFR?

A

Inulin (plant polysaccharide) passes through the kidneys with no amount of inulin secreted or reabsorbed.

—> therefore, clearance rate = GFR (can be used clinically to determine GFR)

(Gold standard for estimating eGFR, but not always accessible in a clinical setting)

161
Q

PAH clearance test (blood test)

A

measures the amount of plasma that passes through the kidneys in one minute (typically 650 mL/min)

(PAH (para-aminohippuric acid) is used to measure renal plasma flow b/c when administered via IV it is filtered and secreted in 1 single pass)

162
Q

kdiney failure

A

..

163
Q

kidney failure occurs when ____

A

when the kidneys cannot filter wastes from blood and can no longer maintain homeostasis

164
Q

what happens to GFR during kidney failure?

A

drops too low

165
Q

what are some ways kidney failure impair body systems?

A

Decrease in urine production

Rise in blood pressure
(d/t blood volume?)

Anemia from decline in erythropoietin production

CNS problems (sleeplessness, seizures, delirium, and coma)

166
Q

Chronic kidney failure

describe

A

Kidney function deteriorates gradually
—>
Associated problems accumulate over time

167
Q

can chronic kidney failure be reversed?

A

No.

Progression can be slowed, but the condition is not reversible

168
Q

management of chronic kidney failure involves ____

A

Management involves restricted water, salt, and protein intake

169
Q

restricting water, salt, proteins helps slow progression of chronic kidney failure by _____

A

Reduces strain on urinary system

—> reduce Volume of urine produced

—> reduce Amount of nitrogenous waste generated

170
Q

what is a common complication of reduced renal function?

A

Acidosis

171
Q

how can acidosis during renal failure be countered?

A

can be countered by ingesting bicarbonate ions

172
Q

what are most common causes of chronic kidney failure?

A

Diabetes and hypertension are the most common causes

173
Q

Acute Kidney Injury (AKI)

A

..

174
Q

what happens during AKI?

A

Kidney function deteriorates rapidly in just a few days

(May be impaired for weeks)

175
Q

AKI is a sudden ____

A

Sudden slowing or stopping of filtration (GFR)

176
Q

AKI is caused by

A

toxic drugs,
renal ischemia,
urinary obstruction,
trauma

177
Q

AKI can also be caused by

A

Allergic response to antibiotics or anesthetics in sensitized individuals

178
Q

can partial or complete function be recovered following AKI (acute kidney injury) ?

A

YES.

(only if patients survive the initial incident)

179
Q

Dialysis, define

A

“What is dialysis? Dialysis is a treatment for people whose kidneys are failing. When you have kidney failure, your kidneys don’t filter blood the way they should. As a result, wastes and toxins build up in your bloodstream. Dialysis does the work of your kidneys, removing waste products and excess fluid from the blood.”

“through” + “decompose”

180
Q

dialysis (from class notes)

A

Process of passive diffusion across a selectively permeable membrane

181
Q

hemodialysis

A

Uses an artificial membrane as an alternative to the kidney’s normal membrane around the glomerulus

Regulates the composition of blood using a dialysis machine

Membrane pores allow diffusion of ions, nutrients, and organic wastes, but not plasma proteins

Dialysis fluid containing specific concentrations of solutes is run on the other side of the membrane

182
Q

is dialysis a cure?

A

no

Dialysis relieves renal failure symptoms, but is not a cure

183
Q

what is the ultimate treatment for kidney failure?

A

Kidney transplant is the only real cure for severe renal failure

184
Q

patient survival 2 years post-transplant

A

> 90 percent at 2 years after the transplant

185
Q

what increases success rate of transplant?

A

Close relative donor increases success rate

186
Q

post-transplant complication?

A

immune response to transplant

Immunosuppressive drugs are necessary to reduce rejection of transplant

187
Q

urinary tract

A

..

188
Q

urinary tract functions

A

transports urine
Stores urine
eliminates urine

189
Q

urinary tract components

A

ureters

urinary bladder

urethra

190
Q

ureters

A

receive urine from the kidneys

Conduct urine to the urinary bladder by gravity and peristalsis

191
Q

urinary bladder

A

receives and stores urine

contraction of muscle in walls drives urination

192
Q

urethra

A

conducts urine from the bladder to outside the body

In the penis, also conducts semen

193
Q

ureters transports urine from ___ to ___

A

transport urine from renal pelvis —> bladder

194
Q

ureters, app length

A

Paired muscular tubes extending from the kidney to the urinary bladder
(about 30 cm)

195
Q

ureters positioning & attachment

A

Retroperitoneal and attached to the posterior abdominal wall

196
Q

ureters three layers (histology)

A

mucosa

muscularis

adventitia

197
Q

ureter mucosa structure

A

transitional epithelium (urothelium)

198
Q

ureters muscularis (structure)

A

2 layers of smooth muscle for peristalsis

199
Q

ureters adventitia

A

outer connective tissue layer

anchors ureters to wall of peritoneum

200
Q

urinary bladder, location

A

Located posterior to pubic symphysis

201
Q

urinary bladder, filled by ___ and drained by ___

A

Filled by the ureters and drained by the urethra

202
Q

bladder, dimensions

A

Dimensions vary with state of distension

203
Q

bladder, position vs peritoneum

A

outside the peritoneal cavity

subperitoneal

204
Q

bladder, attachment to pelvis (inc. pubis)

A

supporting ligaments:

Lateral umbilical ligaments
Middle umbilical ligament

205
Q

umbilical define

A
  1. : of, relating to, or used at the navel.
  2. : of or relating to the central region of the abdomen.

in this case, possibly referring to 2.

206
Q

urinary bladder – rugae

A

Folds in the bladder lining that disappear with expansion as the bladder fills

207
Q

urinary bladder – ureteric orifices

A

Two (one for each ureter) on the posterior inferior surface

Slit-like shape helps prevent backflow of urine into ureters with bladder contraction

208
Q

urinary bladder – internal urethral orifice

A

Where urine leaves the bladder and enters the urethra

209
Q

bladder, TRIGONE

A

Triangular area bounded by the two ureteral openings and the entrance to the urethra

210
Q

trigone define

A

“a smooth triangular area on the inner surface of the bladder limited by the apertures of the ureters and urethra.”

211
Q

Neck of the urinary bladder

what does neck “ contain?

A

Surrounds the urethral opening

Contains a muscular INTERNAL URETHRAL SPHINCTER

212
Q

is internal urethral sphincter voluntary?

A

involuntary smooth muscle

213
Q

External urethral sphincter

male vs female location

A

Located distal to prostate in males

In females, located in similar location to males, at pelvic floor boundary

214
Q

is external urethral sphincter voluntary or involuntary?

A

Under voluntary control

Must be voluntarily relaxed to permit urination

215
Q

urinary bladder, layers

A

mucosa, submucosa, muscularis, and connective tissue layers

216
Q

urinary bladder vs ureters — layers

A

bladder also has SUBMUCOSA

217
Q

bladder, mucosa

A

Contains rugae

Lined with transitional epithelium (urothelium)

Both allow for expansion to hold urine

218
Q

do ureters also have transitional epithelium (urothelium)

A

yes

219
Q

bladder, muscularis – three layers

A

Inner longitudinal layer
Circular layer
Outer longitudinal layer

220
Q

what are the three muscular layers of bladder called?

A

Collectively, the layers form the DETRUSOR muscles

221
Q

detrusor etymology

A

detrus-
–> “thrust down”

222
Q

urethra — from ____ to ____

A

Extends from the
A) neck of the urinary bladder

—> to the
B) exterior of the body

223
Q

urethra, male vs female

(length/function)

A

Male urethra is longer and transports semen as well as urine

224
Q

female urinary tract

A

4cm long

Opens into orifice between clitoris & vagina

225
Q

male urinary tract

A

20cm long

also carries semen

tube passes through prostate

226
Q

three sections of male urinary tract

A

prostatic urethra,
membranous urethra,
spongy urethra

227
Q

internal lining of urethra

A

stratified epithelium that varies by location

228
Q

urethra lining “at neck”

(below neck of bladder?)

A

“Transitional at the neck”

229
Q

urethra lining at midpoint

A

Stratified columnar

230
Q

urethra lining near external urethral orifice

A

Stratified squamous

231
Q

lamina propria of urethra

A

Thick, elastic lamina propria

232
Q

aside note: SEROSA vs ADVENTITIA

A

“Serosa covers intraperitoneal structures and is continuous with the parietal peritoneum. It is thin and consists of a double wall of simple squamous epithelium.”

“Adventitia covers retroperitoneal structures. It is made of fibrous connective tissue and fixes structures in place.”

____

“Some parts of the digestive tract have an adventitia as outer layer instead of a serosa.”

233
Q

note longitudinal folds in mucous membrane of URETHRA

A

Mucin-secreting cells in the epithelial pockets

234
Q

micturition

A

.

235
Q

micturition define

A

process where urine is expelled from the body.

236
Q

micturition etymology

A

From Latin micturio (“to urinateâ€).

237
Q

urine storage reflex

A

Stretch receptors of urinary bladder wall distort as it fills

Afferent impulses stimulate sympathetic stimulation to detrusor and stimulate contraction of internal urethral sphincter

Pontine storage center decreases parasympathetic activity and increases
somatic motor nerve activity
of external urethral sphincter

238
Q

sympathetic/parasympathetic nervous system, external urethral sphincter, detrusor mm

A

“parasympathetic fibers produce contraction of the detrusor muscle by acting at M3 receptors; and sympathetic innervation inhibits detrusor contraction through β3 receptors, and contraction of the internal urethral sphincter by α1 receptor activation.”

239
Q

Micturition reflex (urination)

A

Coordinates the process of urination

240
Q

is micturition reflex local or via CNS pathway?

A

BOTH.

Local reflex pathway
+
Central pathway through the cerebral cortex

241
Q

Urine voiding reflex

A

through pontine micturition center

Afferent information of sensation of bladder fullness relayed to the THALAMUS

242
Q

at what bladder volume do stretch receptors signal CNS?

A

200-400mL
—>
Stretch receptors signal spinal cord & brain when volume 200-400ml

243
Q

projection fibres relay information to ____

A

CEREBRAL CORTEX

Projection fibers relay the information to the cerebral cortex
—>
For voluntary relaxation of the external urethral sphincter

—> Causes contraction of the detrusor muscle and relaxation of the internal urethral sphincter

—> Since pressure is already increased, relaxing the sphincters leads to urination

244
Q

URINARY DISORDERS

A

…

245
Q

primary signs of urinary disorders

A

changes in volume and appearance of urine

246
Q

changes in volume and appearance of urine — E.g.

A

Polyuria

Oliguria

Anuria

247
Q

Polyuria

A

Excessive urine production

Results from hormonal or metabolic problems

—> Possibly DIABETES or GLOMERULONEPHRITIS

248
Q

Oliguria

A

Reduced urine production (50–500 mL/day)

249
Q

Anuria

A

Severely reduced urine production (0–50 mL/day)

250
Q

when does urination indicate potentially serious problem?

A

Oliguria and Anuria

indicate serious kidney problems and potential renal failure

251
Q

changes in frequency as sign of urinary disorders

A

Increased urgency or frequency

Incontinence

252
Q

Increased urgency or frequency

A

Can be from irritation of the lining of the ureters or urinary bladder

253
Q

urgency/frequency – potential causes

A

UTI, prostatitis, diabetes, kidney stones, etc.

254
Q

incontinence

A

Inability to control urination voluntarily

255
Q

incontinence types

A

stress incontinence

urge incontinence

overflow incontinence

256
Q

stress incontinence

A

periodic involuntary leakage

257
Q

urge incontinence

A

inability to delay urination

258
Q

overflow incontinence

A

continual trickle of urine from full bladder

259
Q

Urinary retention

A

Initially normal renal function

Urination does not occur

260
Q

males and urinary retention, vs prostate

A

(Urination function reduced (?))

In males, commonly results from enlarged prostate gland and compression of prostatic urethra

261
Q

pain and urination

A

Pain in the superior pubic region
—>
Associated with urinary bladder disorders

262
Q

Pain in the superior lumbar region or in the flank that radiates to the right or left upper quadrants

A

Associated with kidney infections (pyelonephritis)

Also associated with kidney stones (renal calculi)

263
Q

pyelonephritis

A

Pyelo: a prefix that means that a term is related to the renal pelvis, e.g. pyelonephritis, pyelogram.

264
Q

Dysuria

A

Painful or difficult urination

Can occur with cystitis or urethritis or urinary obstructions (possibly enlarged prostate in males)

265
Q

systemic/clinical signs of urinary system disorders

A

Commonly develops when urinary system is infected with pathogens

Cystitis (bladder infection)—usually low-grade fever

Pyelonephritis (kidney infection) can produce very high fevers

266
Q

cystitis vs pyelonephritis fever intensity

A

Pyelonephritis can produce very HIGH fevers

Semester 4 (30 decks)

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