Section 4 Flashcards Preview

Physiology > Section 4 > Flashcards

Flashcards in Section 4 Deck (208):
1

Avg plasma conc of Na+, Cl-, HcO3-, K+, Ca2+, and P:

140mM, 100mM, 24mM, 4mM, 2.5mM, 1mM

2

Osmolarity of blood:

300 mOsm

3

Fxns of kidney:

To REGULATE body fluid osmolality and V, electrolyte balance and acid balance, to EXCRETE wastes and foreign substances, and to PRODUCE and SECRETE hormones

4

How many liters do the kidneys filter per day?

180L

5

Daily urine output:

1.5L

6

Plasma V:

2L

7

% of plasma that enters the glomerular capillaries that is filtered into the nephrons:

15%

8

Blood supply to the renal tubules:

efferent arteriles

9

What are the renal tubules?

peritubular capillaries

10

The peritubular capillaries merge to form:

renal vein

11

What type of a filtrate enters Bowman's space?

Protein-free plasma unltrafiltrate

12

What makes up the glomerulus?

Glomerular capillaries and mesangial cells

13

What are mesangial ells?

modified s.m. cells, regulatory roles

14

Components of renal corpuscle:

Glomerulus and Bowman's Capsule

15

Components of juxtaglomerulus apparatus:

Mesangial cells of G, macula dense (ThickAL), and Renin secreting granular cell (afferent arteriole/ juxtaglomerular apparatus)

16

What cells secrete renin?

Granular cells of afferent arteriole

17

In which portion of the tubule system are the macula densa?

ThickAL

18

Solutes entering cells of macular dense from tubules:

Na, Cl, and K

19

Solutes moving in and out of cells of macula dense on side opposite tubule:

K in, Na and ATP out

20

ATP released from manual dense cells acts on:

ADO/A1 and ATP/P2X (of Granular and VSM cells) (check)

21

Too much fluid fluid through G and into Bowman's space is controlled via signaling from:

cells of macula densa that sense high NaCl conc in the DT fluid

22

Where in tubule system are macula dense cells found?

ThickAL and DT? Or do the cell of the ThickAL sense the higher conc of NaCl in the adjacent DT?

23

What signals inhibit renin release?

Ca2+

24

Effects of inhibition of renin release:

constriction of afferent arterioles and decrease in GFR

25

Filtration barrier is formed by;

leaky endo cells of G caps, BM around endo cells, foot processes of podocytes

26

What type of barrier is the BM?

Charge-selective

27

What type of barrier is the filtration slit?

size-selective

28

GFR:

fluid flow across filtration barrier (V/t)

29

Often a first sign of kidney disease:

fall in GFR

30

How is GFR monitored?

blood/urine tests

31

What is used for the calculation of GFR?

clearance, also (V/t)

32

Clearance:

volume of blood that can be cleared of a substance/ t

33

T or F? The clearance rate is always the same as the urine flow.

F.

34

Rate of appearance of a substance in urine must equal:

its rate of removal from plasma

35

Rate of appearance in urine:

U(x) (conc of X in urine) X (V*) (urine flow rate)

36

Rate of removal from plasma:

P(x) (conc of X in plasma) X Clearance

37

Clearance =

(conc of X in urine / conc of X in plasma) X flow rate: part over whole times flow rate

38

Large clearance value indicates:

well removed from plasma

39

When does clearance = renal plasma flow?

when substance is completely cleared

40

Clearance for an substance that is not completely cleared is calculated using;

sum of filtration, reabsorption, and secretion

41

Substances hat are neither reabsorbed or secreted:

inulin and creatine

42

Estimate for GFR:

usually from plasma conc of creatinine, can also be done by dividing urine conc by blood conc and multiplying by the urine output in that 24 hour time frame

43

How is GFR controlled?

Starling Forces (hydrostatic vs. oncotic P's)

44

Hydrostatic P:

force exerted by plasma fluid on cap walls

45

Oncotic P:

Osmotic pull exerted by plasma proteins

46

Afferent arteriole P vs. efferent:

17 mm Hg vs. 8 mm Hg

47

What does the ultrafiltration coefficient account for?

variations in permeability and s.a. of the cap

48

3 forces to bo considered in the the filtration capsule when calculating ultrafiltration pressure:

hydrostatic P's of both GC and BS and ONLY oncotic P of GC (no protein in BS)

49

Precise equation for GFR:

K(f) X ultrafiltration P

50

ultrafiltration P:

P(GC) - P(BS) - pi (GC)

51

What changes the GFR bw the afferent and efferent arterioles?

difference in resistances

52

Cells of the DT and CD:

principal and intercalated cells

53

Portions of tubules in outer medulla:

Thick and DL, Thick AL, and CD

54

Portions of tubules in inner medulla:

ThinDL, ThinAL, and CD

55

Proteins forming tight junctions:

claudins

56

Are the N terminal and C terminal ends of the cloudiness facing the apical side?

N terminal

57

How many mOsmol per day must the kidney excrete?

600, regardless of water V excreted

58

Omolar clearance =

(Urine osmolarity / Plasma osmolarity) X Urine flow

59

Urine flow =

osmolar clearance + free water clearance

60

What info does the value of free water clearance provide?

ability of kidney to conc or dilute urine

61

Will C water be positive or negative if water is being generated in the tubule lumen?

positive

62

How do the kidneys create a positive free water in tubule lumen?

reabsorbing NaCl and urea in excess of water along nephron segments with low water permeability

63

How is water added to the the tubule fluid to create a positive free water in the tubule lumen?

Its not! NaCl and urea are taken out in a segment not permeable to water so it can't follow

64

How does the kidney remove water from the tubule fluid to create a negative C water?

by allowing water to exit down its gradient into medullary interstitial fluid

65

Is more or less water being excreted if there is a neg C water?

less

66

How is the fluid in the loop of Henle diluted?

both the single effect and countercurrent multiplier

67

Effects of the the single effect and countercurrent multiplier:

dilute tubule fluid in loop of Henle and concentrate fluid in the medullary interstitium

68

in which segments of the tubule system is the concentration of the tubule fluid compared to that of the plasma remaining constant?

PT, early part of CD, and urine

69

in which segments of the tubule system is the concentraion of the tubule fluid compared to that of the plasma rising?

DL of loop of Henle, DT, and later part of CD

70

only segment of the tubule in which the concentraion of the tubule fluid compared to that of the plasma is decreasing:

Ascending limb of loop of Henle

71

ADH affects which part of the tubule system?

CD

72

How does ADH increase permeability of the CD?

inc # of AQP2 in pm

73

The macula dense of the ThickAL is adjacent to:

afferent and efferent arterioles entering G

74

1st half of PT paracellular pwy:

water, K, and Ca

75

1st half of PT transcellular pwy:

Lumen side: Na, Ca, glucose/P/ or AA and water in, H out plasma membrane: Na, Ca, (glucose/P/ or AA), HCO3-, water out and K, Na, H, and Ca in

76

Solutes reabsorbed via transcellular pwy in the 1st part of PT:

Na, P, glucose, AA

77

Via which route(s) does water follow along an osmotic gradient in the

both trans and para

78

What solutes are moved via solvent drag in the PT?

K and Ca via the para pwy

79

Major site of HCO3- reabsorption, HCO3- generation, and H+ secretion:

first half of PT

80

Movement of what solutes in the PT require energy?

Na, K, and H

81

2nd half of PT transcellular pwy:

Lumen: Na, Ca, Cl in, H and OA- (organic acid) out, plasma membrane: Na, K, Ca, and Cl out, K, H, Na, OA- in

82

2nd half of PT para pwy:

Cl, Na, K, Ca2+, H20

83

Site of transcellular organic acid secretion:

2nd half of PT

84

Site of Cl reabsorption:

2nd half of PT

85

T or F? Cl is reabsorbed in both 1st and 2nd half of PT.

F. 2nd half only and via both trans and para

86

Solutes that move across both para and trans pwys in the 2nd part of PT:

Na, Cl, K,

87

Solutes that move via the para pwy only in the 2nd part of PT:

Ca and water

88

Solutes that move via the trans pwy only in the 2nd part of PT:

H, OA-

89

What generates a transepi electrical gradient that promotes paracellular Na, K, and Ca reabsorption?

movement of unaccompanied Cl

90

T or F? Cl moves via the para pwy in the 2nd part of PT but water can not follow.

F. it does

91

How is Ca moved transcellularly?

bound to calbindin

92

What prevents in inc in intracellular Ca concentration when moving Ca through the cell?

it is bound to calbindin

93

In which portion of the cell does Ca/calbindin binding occur?

cytosol

94

How can Ca sequestered by proteins in plasma be released?

H+ in acidosis

95

is the thin DL permeable to water?

yes

96

Via what pwy does water leave the thin DL?

trans

97

Via which type of aquaporin does water flow out of the thin DL?

AQP1

98

t or F? The thin DL contributes tot he countercurrent multiplier mechanism.

T

99

AQP1 is found here and AQP2 is found here:

thin DL, CD

100

T or F? The Thin AL is permeable to salt.

T

101

T or F? The Thin AL is permeable to water.

F.

102

Why does the conc of the tubular fluid decrease as the fluid ascends in the ascending limb?

salt leaves via para pwy

103

Via what pwy does salt leave the ascending limb?

para

104

T or F? The Thin AL contributes to the countercurrent multiplier system.

T

105

What solutes are reabsorbed via the trans pwy in the Thick AL?

Na, K, and Cl

106

Is the Thick AL permeable to water?

no

107

T or F?The Thick AL contributes to both the single effect and the countercurrent mechanisms.

T

108

The single effect and the countercurrent mechanisms both contribute to:

urine concentration and transepi voltage that promotes reabsorption of Na, K and Ca via the para route

109

Solutes moved via trans pwy in the Thick AL:

Lumen: Na, K, Ca, and Cl in, K out, plasma membrane: Na, K, Ca, and Cl out, K, Na, and H in

110

Solutes moved via the para pwy in the Thick AL:

Na, K and Ca

111

The early DT is similar to the TAL except:

it is independent of K

112

Is the lumen side apical or basal?

apical

113

What provides the permeability to the apical side of the early DT?

Na/Cl contransporter (NCC)

114

What is the NCC?

Na/Cl co-transporter

115

What hormone increases the abundance of NCC?

aldosterone

116

What does increasing the abundance of NCC do?

inc salt reabsorption when BP is low

117

Solutes moved via the trans pwy in the early distal tubule:

Lumen side: Na and Cl in, plasma membrane: Na and Cl out, K in

118

What cells provide transcellular water permeability?

principal cells

119

Na permeability of the principal cells is provided by these channels:

ENac

120

T or F? ENac channel are found on both eh apical and basal side of the principal cells.

F. (check, only shown on apical side)

121

What provides an electrical driving force for transcellular K secretion ad Cl reabsorption in the principal cells?

na reabsorption

122

What channels provide an electrical gradient in principal cells by transporting K into the lumen?

ROMK

123

What channels provide an electrical gradient in principal cells by transporting Na into the cell from the lumen?

ENac

124

What solutes are transported via the paracellular pwy bw principal cells?

Cl-

125

What cells do all the fine tuning of urine/plasma content?

Principal

126

This is a major site of regulation in the tubule system?

Principal cells

127

Does aldosterone increase or decrease the activity of ENac when BP is low or K plasma conc is too high? ? what about ROMK? What about Na,K ATPase?

increase activity of all

128

Location of low pressure sensors:

wall of atria, R vent, and pulmonary vessels

129

T or F? An increase in dissension of the low-pressure sensors causes signals to be sent to the brainstem that stimulate sym n. activity.

F. dec in distension

130

Activation of low-pressure sensors leads to:

inc sym n. activity to inc Na reabsorption, stimulate renin/angiotensin/ aldosterone release to inc BP and Na reabsorption, stimulate ADH release to inc water reabsorption

131

These effects inc Na reabsorption:

sym n activity and renin/angiotensin/aldosterone release

132

T or F? ADH release leads to Na reabsorption.

F. water reabsorption

133

Location of high-pressure sensors:

walls of aortic arch, carotid sinus, and afferent arterioles

134

Activation of high-pressure sensors leads to:

reduce sym n. activity to increase Na excretion, inhibit ADH release to inc water excretion, heart cells release ANP and BNP

135

ANP and BNP are both:

natriuretic peptides

136

Effect of natriuretic peptides:

inc salt and water excretion

137

When is the RAAS activated?

dec Na/water reabsorption that lowers the ECF

138

From where is renin released?

granular cells, also produced and stored here

139

Where are the granule cells that store renin located?

afferent arteriole

140

What leads to the release of renin?

dec P in arteriole, low P in BV's, dec Na delivery sensed by macula densa

141

What happens when the macula densa senses a reduction in Na delivery?

the macula densa stops sending inhibitory input to the renin producing cells

142

What intrinsic signaling capability does the macula dense have?

none

143

T or F? Renin is a protease.

T. helps generate Angiotensin II

144

Effects of Ang II:

sm contraction in BVs to inc BP during water/salt depletion, inc Na/H20 reabsorption by the PT, release of aldosterone

145

What hormone triggers the release of aldosterone?

Ang II

146

On what transporters does activated Ang II receps act?

Na/H exchangers, Na/K pump, and Na?HCO3- co-transporter

147

What type of hormone is aldosterone?

steroid hormone

148

Where is aldosterone both synthesized and secreted?

glomerulosa cells in cortex of adrenal gland

149

Triggers for aldosterone secretion:

inc levels of Ang II indicating dec Bp and Na delivery to macula densa, inc innervation of the adrenal cortex by symp nn. triggered by low P sensors in circulation

150

On which portions of the tubules does aldosterone exert its effects?

DT ad CD

151

Where does Ang II exert its effects?

PT and vasculature

152

2 types of intercalated cells:

alpha and beta

153

alpha intercalated cells:

secrete acid, maximize H+ secretion in acidosis

154

B-intercalated cells:

secrete base, secrete HCO3- in alkalosis

155

Which cells are active during acidosis?

alpha intercalated cells

156

What cells are active during alkalosis?

beta-intercalated

157

Difference bw alpha and beta intercalated cells in terms of location of channels:

alpha: Cl/HCO3- exchanger on plasma membrane and pumps H and Cl out into lumen, beta: Cl/HCO3- exchanger on lumen side and pumps H and Cl out into blood

158

On which side of the beta intercalated cell is the Cl/HCO3- exchanger?

luminal side

159

Changes in HCO3- concentration can lead to both:

metabolic acidosis and alkalosis

160

changes in dissolved CO2 concentrations can lead to both:

respiratory acidosis and alkalosis

161

When the efferent arteriole is constricted does P(GC) increase or P(GS)?

P(GC)

162

Ultrafiltration calculation:

Hydro P of G - Hydro P of Bowman's Space - oncotic P of G

163

Who does aldosterone increase the Na permeability of the DT?

inc # of Na/Cl co-transporters in the plasma membrane

164

A dec in plasma Co2 conc wo a change in plasma HCO3- conc is:

resp alkalosis

165

This leads to dec in renal Na reabsorption:

ANP release

166

Why is it called a multiplier system/

Bc the effects of the gradient are multiplied by the countercurrent system.

167

In which limbs does water leave the tubule passively?

the descending limb and the CD

168

The characteristic yellow color of urine is attributed to:

urobilin

169

The kidneys are located:

behind the peritoneal membrane

170

Blood flow through the kidney includes a feature seen in only a few organs. What is it?

portal system

171

Glucose and amino acids are reabsorbed by:

sodium coupled symporter

172

Primary mode of transport of glucose across kidney epi:

symport with a cation

173

Primary mode of transport of urea across kidney epi:

passive reabsorption/diffusion

174

Primary mode of transport of small plasma proteins across kidney epi

transcytosis

175

These lie between and around the glomerular capillaries:

mesangial cells

176

The specialized cells found in the capsule epithelium are called __________. These cells have long cytoplasmic extensions called __________.

podocytes, foot processes

177

Damage to the renal medulla would interfere first with the functioning of the:

collecting ducts

178

If blood flow through the afferent arterioles increases:

stretch reflexes trigger vasoconstriction to reduce the flow

179

How and where is urea reabsorbed?

passively, proximal tubule

180

In the lumen of the proximal tubule, the Na+concentration __higher/less/same________ the Na+concentration inside the cells of the tubule epithelium.

is much higher than

181

One substance has no membrane transporters to move it but can diffuse freely through open leak channels if there is a concentration gradient. Initially, this substance's concentrations in the filtrate and extracellular fluid are equal. Later, however, the active transport of Na+and other solutes creates a gradient by removing water from the lumen of the tubule where it is located. What substance is this?

urea

182

Which of the following “real” volumes plays the most important role in determining an optimum effective circulating volume?

plasma volume

183

Which of the following fluid compartments has the smallest volume?

plasma volume

184

What percentage of the body weight of a normal adult human is composed of water?

60%

185

Aldosterone stimulates sodium reabsorption

cortical collecting duct.

186

Tubulo-glomerular feedback is an important mechanism that

balances tubular filtration with reabsorption

187

The primary route for ion loss from the body is the __________ system

urinary

188

Cell volume (and therefore cell function) in most cells is dependent upon careful regulation of:

osmolarity of extracellular fluid

189

The two organ systems that work together to regulate mostaspects of the body's water balance are:

urinary and cardiovascular

190

Where is most body water located?

inside cells

191

Kidneys regulate:

water loss, not water gain

192

When a body is dehydrated, water in the urinary bladder:

can be returned to the circulation directly.(?)

193

The hormone that regulates water excretion by the kidneys

ncreases water permeability throughout the kidney tubules

194

The primary osmoreceptors are located in the:

hypothalamus

195

Osmoreceptors depolarize after they __________ in response to __________ plasma osmolarity.

shrink, increase

196

2 fxns of atrial natriuretic peptide:

increases the GFR and inhibit release of renin

197

Thirst is triggered:

when plasma osmolarity is elevated above normal

198

Angiotensin I is converted to angiotensin II by enzymes primarily located in the:

blood vessels

199

The primary role of the carbonic acid-bicarbonate buffer system is:

the prevention of pH changes caused by organic and fixed acids

200

As a result of respiratory alkalosis:

the body retains less carbon dioxide

201

A person who suffers from emphysema will exhibit signs of:

resp acidosis

202

When the pH of body fluids begins to fall, proteins will

bind a hydrogen at the amino group

203

When the pH of the extracellular fluid declines:

the pH of the urine decreases

204

Dehydration may cause some ions to become concentrated. If a person was suffering from severe hyperkalemia, you would expect

the skeletal muscles to be unresponsive and cardiac arrest could occur

205

The hydrostatic pressure in the glomerular capillary is 68 mmHg. The hydrostatic pressure in Bowman’s capsule is 24 mmHg. The oncotic (colloid) osmotic pressure in the glomerular capillary is 18 mmHg. The filtration coefficient is 0.5 ml/min/mmHg. The net filtration pressure is _____ mmHg.

26

206

Which of the following is/are directly involved in autoregulation of the GFR?

A myogenic mechanism in which the afferent arteriole automatically constricts when it is stretched AND a feedback mechanism in which vasoactive chemicals released from the juxtaglomerular apparatus bring about afferent arteriolar vasoconstriction

207

The osmolality of the tubular fluid exiting the earlydistal tubule is always:

hypo-osmotic to plasma

208

Which of the following substances has the highest renal clearance?

Para-amino hippurate (PAH)