Exam III Flashcards Preview

A. White- Human Physiology > Exam III > Flashcards

Flashcards in Exam III Deck (200):
1

What are the three components of the filtration barrier?

Endothelium

Basement membrane

Podocytes

2

What is the glomerular filtration rate determined by?

osmotic and hydrostatic forces.

capillary filtration coefficient

3

What is the daily glomerular filtration rate

125 mL/min or 180 L/day

4

What are some diseases that lower the glomerular filtration coefficient?

diabetes, hypertension

5

What is minimal change nephropathy?

A loss of negative charge in the basement membrane

6

What is hydronephrosis?

Distension and dilation of renal pelvices

7

How is glomerular filtration rate calculated?

GFR = K1(Pg-Pb-Lg+Lb)

Pg = glomerular hydrostatic pressure
Pb = Bowman's capsule hydrostatic pressure
Lg = glomerular capilly coilloid osmotic pressure
Lb = colloid osmotic pressure of Bowman's capsule

8

Increasing what factor will increase glomerular colloid osmotic pressure?

filtration fraction

9

What effect does arterial pressure have on GFR?

it increases it.

10

What effect does afferent pressure have on GFR?

It decreases it

11

What effect does efferent pressure have on GFR?

It increases it

12

What effect does activation of the sympathetic system have on GFR?

It constricts arterioles and decreases blood flow and GFR.

13

What hormones affect GFR?

Norepinephrine

Endothelin

Angiotensin II

Endothelial-derived NO

Prostaglandins and bradykinin

14

What is endothelin released by?

damaged vascular endothelial cells of the kidneys and other tisues.

15

What effect does endothelin have on GFR?

it leads to vasoconstriction and reduced GFR.

16

How does angiotensin affect GFR?

It constricts Efferent arterioles, which increases GFR.

Afferent arterioles are protected against the effects of angiotensin II.

17

What is the origin of nitric oxide?

endothelial cells.

18

What is the effect of nitric oxide on GFR?

It helps maintain renal vasodilation

19

What is the effect of prostaglandins and bradykinins on GFR?

It offsets effects of sympatheti and angiotensin II vasoconstrctor effects.

20

What does autoregulation refer to?

maintaining a relatively consant GFR and renal blood flow.

21

What are the two tubuloglomerular feedback mechanisms for autoregulation?

afferent

efferent

22

What are the comonents of the juxtraglomerular complex (autoregulation)?

macula densa cells

juxtaglomerular cells in afferent and efferent arterioles.

23

When GFR decreases, how is the flow rate affected?

The flow rate int he loop of Henle slows down. There is increased reabsorption of sodium and chloride ions here, and less at the macula densa.

24

Once the macula densa reabsorbs less sodium chloride, what does it signal?

increased renin release from the JG cells. This increases angiotensin and efferent arteriolar resistance.

25

Where is glucose absorbed?

proximal convoluted tubule

26

What receptor reabsorbs 90% of glucose in the early proximal tubule?

SGLT2 via secondary active transport

27

What is the difference between sodium absorption in the first and second half of the proximal tubule?

In the first half, reabsorption is via co transort along with glucose, amino acids, and other solutes.

In the second half, reabsorption is mostly with chloride ions.

28

How is sodium transported in the peoximule tubule?

via antiport with H+

29

What is the thin descending segment of the loop of henel highly permeable to?

water.

It is also moderately permeable to most solutes, including urea and sodium.

30

What is the thin ascending segment of the loop of Henle impermeable to?

water

31

What diuretics are used at the thick ascending segment of the loop of Henle?

furosemide

etacrynic acid

bumetanide

32

What is the distal tubule impreameble to?

water and urea

33

Where are principal and intercalated cells found?

In the late distal tubule and collecting tubules

34

What do principal cells reabsorb and secrete?

reabsorb Na+, secrete K+

35

What diuretics are used at the principal cells?

spironolactone, eplerenone, amilrodie, triameterene

36

What do intercalated cells reabsorb and secrete?

reabsorb potassium, secrete hydrogen ions.

It also reabsorbs water in the presence of ADH

37

What is the permeability to water in the medullary collecting duct controlled by?

ADH

38

what does the collecting duct reabsorb and secrete?

reabsorb: Na, Cl, H2O (in the presence of ADH), urea, HCO3

secrete: H+

39

What is the source of aldosterone?

adrenal cortex

40

What is the functon of aldosterone?

increase sodium reabsorption and stimulate potassium secretion.

41

Where is the site of actionof aldosterone?

the principal cells of cortical collecting ducts

42

An increase of what ionin the extracellular fluid causes the secretion of aldosterone?

potassium

43

What happens in Addison's disease?

A marked loss of sodium and accumulation of potassium due to the absence aldosterone.

44

What syndrome involves the hypersecretion of aldosterone?

Conn's syndrome

45

What does angiotensin II directly stimulate?

sodium reabsorption in proximal tubules, loops of Henle, distal tubules and collecting tubules.

46

What is he source of ADH?

posterior pituitary

47

What is the function of ADH?

to increase water reabsorption

48

Where does ADH bind?

to V2 receptors in late distal tubules, collecting tubules and collecting ducts.

It increases the formation of cAMP

49

What is the source of ANP?

cardiac atrial cells in response to distension

50

what is the function of ANP?

to inhibit reabsorption of sodium and water.

51

What is the source of PTH?

parathyroid glands

52

What is the function of PTH?

increases calcium reabsorption

53

How much water can be excreted by the kidneyes per day when there is a large excess of water in the body?

20 L/day

54

What is the maximal urine concentration that the kidneys can produce?

1200 - 1400 mOsm/L

55

What are the requirements for forming concentrated urine?

presence of ADH

High osmolarity of the renal medullary interstitial tubule.

56

What is the obligatory urine volume, and why is it necessary?

0.5 L/day; it is excreted in order to get rid of waste products of metaolism and ions that are ingested.

57

Where in the kindey tubule are most of the filtered electrolyetes reabsorbed?

in the proximal tubule.

58

What is the descending loop of Henle permeable to?

water

59

When does the tubular fluid become more dilute?

as it moves up the thin ascending loop of Henle. Sodium chloride is reabsorbed here.

60

What is the role of the osmoreceptor ADH feedback mechanism?

It controls extracellular fluid sodium concentration and osmolarity.

61

When the extracellular fluid osmolarity is high, what effect does this have on osmorecetor ells in the anterior hypothalamus?

The cells shrink. ADH is then released, which increases water permeability in distal nephron segments.

62

When does extracellular osmolarity increase?

When therei s a deficit in water. This causese ADH secretion and subsequent water reabsorption.

63

What is the extracellular fluid potassium concentration?

4.2 mEq/L

64

What is the relationship between insulin and potassium?

Insulin stimulates potassium uptake by cells.

65

What is the relationship of aldosterone and potassium?

Aldosterone increases potassium uptake by cells.

66

what is the disorder that involves an excess secretion of aldosterone?

Conn's syndrome

67

What is the disorder that invovles a deficiency in aldosterone secretion?

Addison's disease

68

What is the relationship between beta-adrenergic stimulation and potassium?

epinephrine stimulates potassium uptake by cells.

69

What is the relationship between metabolic acidosis and extracellular potassium?

extracellular potassium increases in metabolic acidosis due to reuctionin activity of the Na/K ATPase pump.

70

What are the effects of hyperkalemia?

cell lysis

strenous exercise

increased extracellular fluid osmolarity

71

What is a buffer?

A substance that can reversibly bind H+.

72

What are three important buffer systems?

bicarbonate

phosphate

proteins as buffers

73

What is the most important extracellular buffer system?

bicarbonate buffer system

74

What is metabolic acidosis?

a decreased concentration of bicarbonate

75

What is metabolic alkalosis?

an increased concentration of bicarbonate

76

What is respiratory acidosis?

an increased concentration of carbon dioxide

77

What is respiratory alkalosis?

a decreased concentration of carbon dioxide.

78

What role does the phosphate buffer system play?

It biffers renal tubular fluid and intracellular fluids

79

What is the primary method for removing nonvoltaile acids?

by excretion.

80

In order to reabsorb bicarbonate, what must happen to it?

It must react with secreted hydrogen ion to form carbonic acid before it can be reabsorbed.

81

What are the three ways that extracellular H+ is regulated?

Reabsorption of filtered bicarbonate ions

Secretion of hydrogen ions

Production of new bicarbonate ions.

82

Where in the kidney tubules does hydrogen ion secretion and reabsorption occur?

Hydrogen ion secretion occurs via secondary active transport in all parts of the tuules except the descending and ascending limbs of the loops of Henle.

83

Where does primary acive hydrogen secretion begin?

In thelate distal tubules (intercalated cells)

84

Where does the majority of bicarbonate reabsorption occur?

proximal tubule

85

How are acidosis and alkalosis corrected?

via incomplete titration. Each time a hydrogen ion is formed in the tubular epithelial cells, a bicarbonate ion is formed and released back into the blood.

86

How does the tubular epithelium secrete hydrogen?

via primary active transport

87

How does the proximal tubule secrete hydrogen?

via secondary counter-transport.

88

What is the lower limit of pH that can be achieved in normal kidneys?

4.5

89

The loss of bicarbonate ions is the ___ as adding hydogen ions to the extracellular fluid.

same

90

Why can only a small partof the excess hydrogion secrete be excreted in the ionic form in urine?

Because the minimal urine pH is about 4.5.

91

How are excess hydrogen ions eliminated?

Through binding with phosphate or ammonia ions.

92

How can the kidneys correct alkalosis?

by failing to reabsorb all the filtered bicaronate ion

93

When does acidosis occur?

when the ratioof bicarbonate ion to carbon dioxide in extracellular fluid decreases.

94

What is the primary compensatory resonse of respiratory acidosis?

Increase in plsam bicarbonate ion

95

What is the primary compensatory response for metabolic acidosis?

increase ventilation rate

96

When does alkalosis occur?

When there is an increase in the ratio of bicarbonate to hydrogen ion concentration.

97

What is the primary compensatory response of alkalosis?

reduction in plasma bicarbonate ion concentration caused by renal excretion of bicarbonate ion.

98

what is the primary compensatory response of metabolic alkalosis?

decreased ventilation\
Increased renal bicarbonate ion excretion.

99

What is total lung capacity?

the maximum volume of gas the lungs can hold.

100

What is tidal volume?

the volume of air that is inspired or expired with each breath at rest. 500 ml

101

What is insiratory reserve volume?

Volume f air that can be inspired in addition to tidal volume with forceful inspiration. 3000 mL

102

What is expiratory reserve volume?

Additional volumeof air that can be expired at end of tidal volume by forceful expiration. 1100 mL

103

What is residual volume?

volume of air remaining in lungs after force expiration. 1200 mL.

104

What vital capacity?

The sum of all the volumes that can be insired or exhaled. 4600 mL

105

What is total lung capacity?

The sum of all the volumes = vital capacity plus residual volume. 5800 mL.

106

What is inspiratory capacity?

The sum of all volumes above resting capcity = tidal volume plus inspiratory reserve volume. 3500 mL

107

What is functional residual capcity?

2300 mL. The sum of volumes below resting capacity = expiratory reserve volume + residual volume.

108

What is minute ventilation?

Total volume of gases moved into or out of the lungs per minute; calculated as breaths per minute x tidal volume.

109

What is alveolar ventilation?

Total volume of gases that enter spaces participating in gas exchange per minute. Calculated as breaths per minute x (tidal volume - dead space).

110

What is anatomic dead space?

trachea, bronchi and bronchioles

111

What is physiological dead space

anatonmic dead space + ventilated alveoli with poor or absent perfusion.

112

What is the total dead psace in a normal individual?

0.15 L.

113

How is alveolar ventilation calculated?

0.35 x breathing rate.

114

What is pleural presure?

pressure of the fluid between parietal pleura and the visceral pleura.

115

What is alveolar pressure?

Pressure of the air inside the alveoli

116

What is transpulmonary pressure?

Difference between the alveolar pressure and the pleural pressure.

117

What is compliance?

The extent to which lungs will expand for each unit increase in the transpulmonary pressure. it is a measure of the expansibility of the lungs and trachea.

118

How is compliance calculated?

increase in volume/increase in pressure

119

What is surfactant produced by?

type II alveolar ells.

120

Why does a saline-filled lung expand more easily than an air-filled lung?

beacuse there is an absence of surface tension forces. Therei s no air-fluid interface.

121

What happens if air passages laeading from the alveoli are blocked?

the surface tension in he alveoli collapses the alveoli.

122

What would happen if there were no surfactant?

Pressure would be about 4.5 times as great in the lungs.

123

What is the high pressure, low flow irculation?

thoracic aorta to bronchial arteries

124

What is the low pressure, high flow circulation?

pulonary artery and branches to alveoli.

There is high compliance.

125

What is pulmonary arterial pressure?

24/9 mm H

126

What is mean pulmonary arterial pressure?

15 mm Hg

127

What is let atrium pressure?

8 mm Hg

128

What is the pressure gradient in the pulmonary system?

7 mm Hg

129

How does failure of the left side of the heart affect pressure?

pressure builds up in pulmonary circulation. Blood volume and pressure are increased.

130

What is a physiologic shunt?

it contains blood that has bypassed the pulmonary capillaries.

131

What occurs when oxygen concentration in the alveoli is 70% or more below normal?

adjacent vessels constrict. Those alveoli that are poorly ventilated get even less blood while those with adequate ventilation get more blood.

132

What is the flow in zone 1?

no blood flow

133

What is the flow in zone 2

intermittent blood flow only during systole

134

What is the flow in zone 3?

continuous blood flow

135

What flow is found in the apices?

zone 2 flow. Exercise can convert apices from zone 2 to zone 3 flow.

136

What is the result of obstructing blood supply to one normal lung?

blood flow through the other lung is doubled. The pulmonary pressure in the other lungs is only slightly increased.

137

What are agents that constrict pulmonary arterioles?

norepinephrine

epinephrine

angiotensin II

some prostaglandins

138

What are some agenst that dilate pulmonary arterioles?

isoproterenol

acetylcholine

139

What is the result of sympathetic vasoconstriction in the pulmonary system/

pulmonary blood flow is decreased by 30%, and blood is mobilized from pulmonary reserves.

140

Pulmonary arterial pressure rises little during maximum exercise. Why is this so?

becaue capillaries open and flow rate increases.

141

In left heart failure, what occurs at the left atrium?

blood begins to dam up.

142

What is the mean filtration pressure in the lungs?

1 mm Hg

143

What is the most common cause of pulmonary edema?

left sided heart failure or mitral valve disease.

Damage of pulmonary blood capillary membranes can also occur.

144

What happens if the pressure in the lungs becomes positive (greater than -4 mm Hg)?

the lungs tend to collapse.

145

What are causes of pleural effusion?

blockage of lymphatic drainage from pleural cavity

Cardiac failure

Reduced plasma colloid osmotic presure

Infection/inflammation

146

How does hypoxia affect presure in the pulmonary artery?

pressure is increased due to prostaglandins.

147

What are the results of a bronchial obstruction?

Decline in pH and vasoconstriction of pulmonary vessels.

148

What is the most abundant gas in air?

nitrogen

149

What is daltons law?

Ptotal = sum of partial pressures

150

What is Boyle's law?

P = 1/V

151

What is Henry's law?

the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

152

What is pressure directly proportional to?

the concentration of the gas molecules.

153

How is partial pressure calciulated?

partial pressure = [dissolved gas]/sol. coefficient

154

What is the relationship between vapor pressure and temperature?

as vapor pressure increases, temperature increases.

155

What factors affect the rate of gas diffusion in a fluid?

solubility of gas in the fluid

Cross sectional area of the fluid

Distance through which the gas must diffuse

Molecular weight of the gase

Temperature of the fluid

156

What is oxygen concentration in the alveoli controlled by?

rate of absorption of oxygen into the blood

rate of new oxygen entry into the lungs

157

Carbon dioxide concentration is controlled by what factors?

rate of carbon dioxide excretion

alveolar ventilation

158

What factors determine how rapidly a gas will pass through the respiratory membrane?

membrane thickness

surface area

diffusion coefficient of gas

partial pressure difference of gas between two sides of the membrane.

159

What does the Va/Q ratio refer to?

alveolar ventilation/blood flow

160

When Va/Q = 0, what type of obstruction i spresent?

an airway o bstruction. There is no ventilation, but there is perfusion. The blood gas composition remains unchanged.

161

When Va/Q = infinity, what type of obstruction is present?

a vessel obstruction. There is ventilation, but no gas exchange.

A physiologic shunt is made.

162

What is physiologic dead space?

shunted blood + anatomic dead space

163

When diffusing capacity increases during exercise, what happens in the lungs?

There is a more ideal V/Q ratio

There is increased surface area of capillaries participating in diffusion.

164

What factors determine tissue PO2?

Rate of oxygen transport to the tissues

Rate of oxygen consumption by the tissues

165

When PO2 is ___, oxygen binds with hemoglobin

high

166

When PO2 is ___, oxygen is released from hemoglobin.

low

167

What factors cause the oxygen-hemoglobin curve to shift to the right?

increased hydrogen ions

increased CO2
Increased temperature

increased BPG

168

What direction is the oxygen-hemoglobin curve shifted when there is an increase in carbon dioxide and H+ ions?

to the right

169

What direction is the oxygen-hemoglobin curve shifted when there is a decrease in blood carbon dixode and H+ ions?

to the left

170

How is carbon dioxide transported?

A small amount is dissolved in the blood

70% is transported as carbonic acid

Remainder is transported as carbamino hemoglobin

171

What is the bohr effect?

An increase in blood carbon dioxide causese oxygen to be displaced from hemoglobin. This shifts the oxygen-hemoglobin curve to the right.

172

What is the Haldane effect?

Binding of oxygen with hemoglobin displaces carbon dioxide from blood. The binding of oxygen cauese hemoglobin to become a stronger acid, and more acidic hemoglobin ha less of a tendency to bind with carbon dioxide.

173

What two respiratiory groups are located in the medullary respiratory centers?

dorsal respiratory group

ventral respiratory group

174

What respiratory groups are located in the pontine respiratory centers?

apneustic center

pneumotaxic center

175

What is the functionof the dorsal respiratory group?

It sets the basic rhythm of respiration.

176

What respiratory group establishes the ramp signal?

dorsal respiratory group

177

How is respiration controlled?

by limiting the point at which ramp suddenly ceasese. The earlier ramp ceases, the shorter the duration of inspiration and respiration.

178

What does a strong PRG signal result in?

30 - 40 breaths/minute

A weak PRG signal results in 3-5 breaths/minute.

179

What does the pneumotaxic center conrol?

the rate and depth of breathing.

180

The loss of function of what respiratory center causese prolonged inspiratory gasping?

apneustic center

181

What respiratory group is inactive during normal quiet respiration?

ventral respiratory group

182

What complex generates the timing and length of the respiratory rhythm?

the pre-botzinger complex

183

What is the Hering-breuer inflation reflex?

Stretch receptors in muscular portions of walls of bronchi and bronchioles activate dorsal respiratory group neurons. This inhibits the inspiratory ramp signal.

184

What is the relationship between chemoreceptors and hypoxia/hypercapnia?

chemoreceptors increase their rate of activity when hypoxia or hypercapnia occur.

185

Where are central chemoreceptors located?

on the ventral surfae of the medulla. They are indirectly sensitive to carbon dioxide levels int he blood.

186

Where are peripheral receptors located?

in the aortic arch. They are sensitive to concentrations of oxygen, carbon dioxide and hydrogen ions.

187

What are central receptors sensitive to?

H+.

188

Sensitivty to increased levels of carbon dioxide lasts for several hurs, but then begins to decline. This is due to adjustments by what organ?

The kidneys.

They increase bicarbonate levels in the blood.

189

Where are most peripheral receptors located?

in the carotid bodies at the bifurcation of the common carotids.

190

What are the two types of carotid body cells?

type I (glomus) and type II (sustenacular cells)

191

What effect does decreased PO2 have on channels?

It closes channels and results in a depolarization that opens calcium channels, leading to neurotransmitter release.

192

Where are slow-adapting stretch receptors located?

within the airways of the lungs.

193

What do signals from the slow adapting stretch receptors do?

terminate inspiration

prolong expiration

194

What are signals for the slow adapting stretch receptors important for?

controlling respiration in infants and adults during exercise.

195

What is the function of rapidly-adapting pulmonary stretch receptors?

eliciting a cough.

196

Where are J receptors located?

in the alveolar wall.

197

What are J receptors sensitive to?

pulmonary edema

198

What does the stimulation of J receptors elicit?

a cough and tachypnea

199

What is Cheyne stokesbreathing

hyperpnea

gradual decrease

apnea

repeat of pattern

200

What factors can cuase Cheyne-Stokes breathing?

A long delay in the transport of bood from the lungs to the brain.

Increased negative feedback.