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Exam 3 Flashcards

1
Q

What is pressure in the cardiovascular system produced by?

A

The heart

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2
Q

Flow is proportional to…

A

1/R

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3
Q

Why does pressure decrease as fluid travels along a tube?

A

Due to friction with wall of tube

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4
Q

What does each side of the heart function as?

A

An independant pump

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5
Q

What do elastic arteries serve as?

A

Pressure reservoir

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6
Q

Why are arterioles the site of variable reistance?

A

Arterioles have high proportion of muscle

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7
Q

Why are capillaries the site for exchange?

A

They are very thin

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8
Q

Why do veins serve as a volume reservoir?

A

Systemic veins have high compliance, not very elastic

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9
Q

What is allocation of blood flow to body structures determined by?

A

Changes in arteriolar resistance

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10
Q

What does vasoconstriction result in?

A

Decrease in pressure downstream & increase in pressure upstream

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11
Q

Why is velocity of blood flow lowest in capillaries?

A

Capillaries have large-cross sectional areas and therefore the lowest velocity. Low velocity allows time for diffusion

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12
Q

What does velocity of flow depend on?

A

Total cross-sectional area of vessels
-large cross-sectional area = low velocity

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13
Q

What are the 3 mechanisms of exchange at capillaries?

A
  1. Diffusion
  2. Vesicular Transport
  3. Bulk Flow
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14
Q

What exchange occurs from diffusion?

A

Small solutes

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15
Q

What exchange occurs from vesicular transport?

A

Large solutes & proteins

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16
Q

What is transcytosis?

A

Combination of endocytosis, vesicular transport, & exocytosis

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17
Q

What exchange occurs from bulk flow?

A

Water + Solutes

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18
Q

What are the two possibilities of exchange from bulk flow?

A
  1. Filtration = from plasma to interstitial fluid
  2. Absorption = from interstitial fluid to plasma
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19
Q

What is bulk flow exchange determined by?

A

-Hydrostatic pressure
-Colloid Osmotic pressure

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20
Q

What is hydrostatic pressure?

A

Lower at venous end due to friction

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21
Q

What is colloid osmotic pressure?

A

Osmotic pressure resulting from proteins restricted to plasma

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22
Q

What is the net filtration pressure (NFP)?

A

Hydrostatic pressure (Ph) - Colloid osmotic pressure (pi)

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23
Q

If NFP > 0, what happens?

A

Net filtration

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24
Q

If NFP < 0, what happens?

A

Net Absorption

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25
Q

Why do we lose about 3L of fluid from plasma per day?

A

Filtration at arterial end usually exceeds absorption at venous end

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26
Q

What is the lymphatic system?

A

System of vessels & nodes that:
-returns excess interstitial fluid to the blood
-returns any filtered protein to the blood
-“filters” out pathogens
-absorbs fats in small intestine

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27
Q

What is edema?

A

Excess interstitial fluid - net filtration exceeds removal by lymphatic system

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28
Q

What is driving pressure?

A

Pressure created in ventricles, transferred to arteries

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29
Q

As blood travels through arteries –> capillaries –> veins, the pressure _______.

A

Decreases

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30
Q

Why do elastic arteries serve as pressure reservoir?

A

-stretch during systole
-elastic recoil maintains driving pressure during diastole

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31
Q

What is backward flow during diastole prevented by?

A

Semilunar valves

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32
Q

When does systolic pressure occur?

A

During ventricular systole

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33
Q

When does diastolic pressure occur?

A

During ventricular diastole

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34
Q

What is pulse pressure (PP)?

A

sBP - dBP

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35
Q

What is the equation for MAP?

A

2/3dBP + 1/3sBP

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36
Q

What is mean arterial pressure?

A

-Reflects driving pressure for blood flow to tissues
-Indicates whether there’s enough pressure to perfuse all organs

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37
Q

What are the factors influencing MAP?

A
  1. Cardiac output
  2. Diameter of arterioles
  3. Blood volume
  4. Diameter of veins
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38
Q

What is the relationship between cardiac output and MAP?

A

Incr. CO = Incr. MAP

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39
Q

What is TPR?

A

Total peripheral resistance = resistance to flow, due to arterioles

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40
Q

What is the relationship between diameter of arterioles and MAP?

A

Decr. diameter = increase TRP = incr. MAP

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41
Q

How does NE change the diameter of arterioles?

A

Most systemic arterioles innervated by SNS neurons which release NE to incr. vasoconstriction through:
-alpha adrenergic receptors
-tonic control

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42
Q

What is the relationship between blood volume and MAP?

A

Incr. Blood Volume = Incr. MAP

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43
Q

What are the responses to changes in blood volume in the cardiovascular system and kidneys?

A

Cardiovascular system = rapid
Kidneys = slow

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44
Q

What is the cardiovascular control center? Where is it located?

A

Control of blood pressure & distribution of blood to tissues. Located in the medulla oblongata

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45
Q

What is the baroreceptor reflex?

A

-Primary reflex pathway for homeostatic control of MAP
-Rapid response
-Functioning all the time

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46
Q

What are baroreceptors?

A

Stretch-sensitive, respond to pressure

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47
Q

What does CVCC control?

A

Controls SNS output to specific regions of body to regulate blood distribution and enhance blood flow in fight-or-flight response.

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48
Q

What are the effects of the binding of NE to A-adrenergic receptors?

A

Widespread Vasoconstriction

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49
Q

What are the effects of the binding of Epi to B2-adrenergic receptors?

A

Vasodilation in skeletal muscle, heart, & liver

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50
Q

What is active hyperemia?

A

Local increase in blood flow due to increase in metabolic activity

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51
Q

Why is active hyperemia important for local control of distribution of blood flow?

A

Important strategy for tissues to regulate their own blood supply.

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52
Q

What are the paracrines causing local vasodilation?

A

-Incr. NO
-Incr. Adenosine
-Incr. Histamine
-Decr. O2
-Incr. CO2
-Incr. H+

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53
Q

What is cellular respiration?

A

Intracellular processes using oxygen to generate ATP + CO2 + H2O

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54
Q

What is external respiration?

A

Movement of gases between atmosphere & cells

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55
Q

What are the types of external respiration?

A
  1. Ventilation
  2. Gas exchange in the pulmonary circuit
  3. Gas transport in the blood
  4. Gas exchange in the systemic circuit
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56
Q

What are the functions of external respiration?

A

-support cellular respiration
-regulation of pH via retention or elimination of CO2

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57
Q

What is alveolar ventilation (Va)?

A

Volume of fresh air that reaches alveoli per minute

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58
Q

What is hyperventilation?

A

Increase Va

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59
Q

What is hypoventilation?

A

Decreased Va

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60
Q

What are the 2 outcomes if ventilation is inadequate?

A

-Hypoxia = insufficient O2 availability to cells
-Hypercapnia = elevated CO2 levels

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61
Q

What does gas exchange (diffusion) require at lungs & tissues?

A

A gradient in partial pressure.

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62
Q

What is partial pressure (Pgas)?

A

Pressure of a single gas

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63
Q

What is Dalton’s Law?

A

Total pressure exerted by mixture of gases = sum of pressures exerted by individual gases

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64
Q

At sea level what is the Patm?

A

760 mmHg

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65
Q

What happens to Pgas and Patm at different altitudes?

A

Pgas & Patm change, but % gas in atmosphere is constant

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66
Q

What is the normal Po2 in our alveoli?

A

100 mmHg

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67
Q

What is the normal Pco2 in our alveoli?

A

40 mmHg

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68
Q

What happens to alveolar Po2 & Pco2 if we hypoventilate?

A

PO2 Decr. & PCO2 Incr.

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69
Q

What happens to alveolar Po2 & Pco2 if we hyperventilate?

A

PO2 Incr. & PCO2 Decr.

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70
Q

In peripheral tissues what is the PO2?

A

40 mmHg

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71
Q

In peripheral tissues what is the PCO2?

A

46 mmHg

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72
Q

What are the factors that increase alveolar gas exchange?

A
  • Incr. partial pressure gradient
  • Incr. surface area
  • decr. diffusion distance
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73
Q

What are conditions that decrease alveolar gas exchange?

A

-Decr. surface area
- Decr. partial pressure gradient
- Incr. diffusion distance

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74
Q

What is Henry’s Law?

A

Movement of gas from air to liquid is proportional to:
1. Solubility
2. Pressure Gradient

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75
Q

What is the Law of mass action for plasma PO2?

A

-Incr. Plasma PO2 causes incr. in binding
-Decr. in plasma PO2 causes decr. in binding and more release O2

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76
Q

What does the amount of O2 bound to Hb depend on?

A

-% saturation of Hb due to Po2
-Number of O2 binding sites (# of RBCs & Hb content per RBC)

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77
Q

What is the oxyhemoglobin saturation curve?

A

Shows % of available binding sites occupied determined by plasma Po2

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78
Q

Why is the shape of the oxyhemoglobin saturation curve important?

A

Sigmodial “S” shape important for delivering O2 to active tissues

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79
Q

What does a right shift curve in the oxyhemoglobin saturation curve mean?

A

Right-shifted curve occurs in active or chronically hypoxic tissues and increases O2 delivery to cells

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80
Q

What is a right shift curve in the oxyhemoglobin saturation curve caused by?

A

-Incr. PCo2
-Decr. pH (due to more lactic acid)
-Incr. temperature
-Incr. 2,3-BPG

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81
Q

What is 2,3-BPG?

A

A molecule that is a byproduct of cellular metabolism in chronically hypoxic cells

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82
Q

What are the 3 ways CO2 is transported in the blood?

A
  1. Dissolved in plasma: 7%
  2. Bound to hemoglobin: 23%
  3. Converted to bicarbonate: 70%
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83
Q

What is the chemical equation for bicarbonate?

A

CO2 + H2O = H2CO3 = H+ + HCO3-

84
Q

What is the law of mass action for bicarbonate?

A

-Hypercapnia –> right shift –> incr. H+ = acidosis
-Hypocapnia –> left shift –> decr. H+ = alkalosis

85
Q

Where does CO2 enter RBC?

A

CO2 enters plasma at tissues –> enters RBC

86
Q

Where does CO2 leave RBC?

A

CO2 leaves plasma at lungs –> leaves RBC

87
Q

What are the features of ventilation?

A

-uses skeletal muscle
-controlled by CNS via somatic motor neurons
-rhythmic process
-does not require conscious effort

88
Q

How is the rhythmic pattern of ventilation generated by the medulla oblongata?

A

-pre-Botzinger complex = “pacermaker” neurons
-Dorsal respiratory group
-Ventral respiratory group

89
Q

What does the dorsal respiratory group of the medulla oblongata do?

A

Regulate inspiratory muscles

90
Q

What does the ventral respiratory group of the medulla oblongata do?

A

Regulate expiratory muscles

91
Q

What does the pontine respiratory groups do to regulate ventilation?

A

Smooths out rhythm

92
Q

What are output signals of ventilation modified by?

A

-Voluntary input from cerebral cortex
-limbic system
-fever
-chemoreceptors

93
Q

What do chemoreceptors do?

A

Monitor CO2, O2, and pH levels

94
Q

Where are chemoreceptors located?

A

-Central chemoreceptors in medulla oblongata
-Peripheral chemoreceptors at carotid arteries & aorta

95
Q

What do the central chemoreceptors do?

A

Sense changes in PCo2 detected as pH of CSF

96
Q

What do the peripheral chemoreceptors do?

A

Sense changes in PCo2, pH, and Po2 in blood

97
Q

What is ventilation normally controlled by?

A

pCO2 and pH

98
Q

What must pO2 fall below in order to affect ventilation?

99
Q

What is the shallow water blackout effect?

A

Swimmers will hyperventilate before diving in order to initially lower their Co2 levels and be able to stay underwater for longer, however blackout will kick in when O2 falls too low

100
Q

What are the mechanics of ventilation?

A

Air flows from regions of higher pressure to lower pressure

101
Q

What is Boyle’s Law?

A

Pressure is inversely related to volume of the container

102
Q

What happens during inspiration?

A
  1. The diaphragm contracts (flattens)
  2. Thoracic volume increases
  3. Lung tissue is stretched
  4. Alveolar volume increases
  5. Alveolar pressure decreases
  6. Air moves into the lungs
103
Q

What kind of muscle is the diaphragm? What kind of motor nerve innervates it?

A

Smooth muscle; somatic motor neuron

104
Q

What happens during expiration?

A
  1. Diaphragm relaxes (unflattens)
  2. Thoracic volume decreases
  3. Elastic recoil of lungs
  4. Decrease in alveolar volume
  5. Increase in alveolar pressure
  6. Air moves out of the lungs
105
Q

How does CO2 affect airway diameter?

A

High CO2 in expired air = bronchodilation

106
Q

How does histamine affect airway diameter?

A

Histamine from mast cells causes bronchoconstriction

107
Q

What influence does the parasympathetic NS have on airway diameter?

A

Parasympathetic –> ACh –> mAChR = constriction

108
Q

What influence does the sympathoadrenal NS have on airway diameter?

A

Sympathoadrenal –> Epi (through blood) –> B2-adrenergic = dilate

109
Q

What is compliance?

A

Ability of lungs to stretch

110
Q

What is elastance?

A

Ability to recoil after stretch

111
Q

What happens when compliance decreases?

A

Difficulty inspiring

112
Q

What happens when elastance decreases?

A

Difficulty expiring

113
Q

What does the narrowing of airways cause?

A

Increased resistance

114
Q

What is tidal volume (Vt)?

A

Volume of air that moves during a single inspiration or expiration

115
Q

What is inspiratory reserve volume (IRV)?

A

Additional Volume you can inspire above tidal volume (Vt)

116
Q

What is expiratory reserve volume (ERV)?

A

Amount of air that can be forcefully exhaled after end of normal expiration

117
Q

What is residual volume (RV)?

A

Volume of air remaining after maximal exhalation

118
Q

What is the equation for vital capacity (VC)?

A

VC = Vt + IRV + ERV

119
Q

What is the equation for total lung capacity (TLC)?

A

TLC = VC + RV

120
Q

What is the ventilation rate (VR)?

A

Breaths per minute

121
Q

What is the minute (total pulmonary) ventilation (Ve)?

A

Volume of air inhaled or exhaled per minute = VR x Vt

122
Q

What are the functions of the kidney?

A
  1. Filter Blood
  2. Play role in hormonal regulation of blood pressure
  3. Storage & release of urine
123
Q

Why does the kidney filter blood?

A

To retain vital substances, eliminate waste, and maintain homeostasis of water & ions

124
Q

What are the 4 processes that occur in the kidney?

A
  1. Filtration
  2. Reabsorption
  3. Secretion
  4. Excretion
125
Q

What function of the kidney occurs at Bowman’s capsule?

A

Filtration

126
Q

What function of the kidney occurs at the proximal tubule?

A

Reabsorption & secretion

127
Q

What function of the kidney occurs at the loop of henle?

A

Reabsorption

128
Q

What function of the kidney occurs at the distal nephron (distal tubule + collecting duct)?

A

Reabsorption & Secretion; final control of water, ions & pH

129
Q

What is the blood supply of the kidney?

A

Renal portal system = Afferent arteriole –> glomerulus –> efferent arteriole –> peritubular capillaries

130
Q

What is produced from filtration in the kidney?

A

Filtrate = filtered plasma without proteins or RBC

131
Q

What is filtration?

A

Passive leakage of plasma

132
Q

What is the renal corpuscle?

A

Glomerulus + Bowman’s capsule

133
Q

What is the filtration fraction?

A

% of plasma passing through glomerulus that is filtered = 20%

134
Q

What is the glomerular filtration rate (GRF)?

A

Volume filtered/ time

135
Q

What are the 3 barriers that substances leaving the plasma must pass?

A
  1. Fenestrated capillary endothelium
  2. Basement membrane
  3. Podocytes (filtration slits) of epithelium of Bowman’s capsule
136
Q

What is the filtration coefficient increased by?

A

-SA of glomerular capillaries
-Permeability of filtration slits

137
Q

What does the GFR in the renal corpuscle depend on?

A

-Glomerular hydrostatic pressure (Ph) = Blood pressure
-Colloid osmotic pressure (pi)
-Capsule fluid pressure

138
Q

What is colloid osmotic pressure?

A

-Due to plasma proteins
-Opposes filtration

139
Q

What is capsule fluid pressure?

A

-due to fluid within Bowman’s capsule
-opposes filtration

140
Q

What are the 2 ways of auto-regulation locally controlled by the kidney to maintain GFR?

A
  1. Autoregulation by myogenic response
  2. Autoregulation by tubuloglomerular feedback
141
Q

How does autoregulation occur by myogenic response?

A

If MAP is too high & GFR is too high this stretches the afferent arteriole smooth muscle
-open stretch-sensitive ion channels
-muscle cell depolarizes
-open Ca2+ channels
-vascular smooth muscle contracts
-vasoconstriction of afferent arteriole incr. resistance to flow
-blood flow through afferent arteriole decr.
-decr. GFR

142
Q

How does autoregulation by tubuloglomerular feedback happen?

A

If GFR too high there is faster fluid flow through tubules
-incr. NaCl detected by macula densa cells
-release paracrine signal to vasoconstrict afferent arteriole
-decr. GFR

143
Q

What are juxtaglomerular apparatus?

A

Specialized region where distal tubule & afferent arteriole meet for regulation of GFR & MAP

144
Q

What are macula densa cells?

A

Part of JGA in wall of tubule

145
Q

What are granular cells?

A

Part of JGA in wall of arteriole

146
Q

What happens under sympathetic input to neural & hormonal effects on GFR?

A

Incr. Epi, NEpi cause vasoconstriction of afferent arteriole to maintain high MAP and decr. GFR to decr. urine production and maintain blood volume

147
Q

What is the primary driving force for most reabsorption?

148
Q

What happens during reabsorption?

A

Filtrate –> interstitial fluid –> blood in peritubular capillaries

149
Q

How is Na+ reabsorbed?

A

Diffuses passively from filtrate into tubule cell via carriers then actively transported into interstitial fluid

150
Q

Why is Na+ the primary driving force for most reabsorption?

A

-Anions follow Na+
-Water follows solutes by osmosis

151
Q

What is the Na+-linked transport used for?

A

Used for reabsorption of many valuable substances such as glucose that is reabsorbed by SGLT transporter against its concentration gradient

152
Q

What is the transport maximum (Tm)?

A

Transport rate at saturation

153
Q

What is the renal threshold?

A

Plasma concentration at which saturation occurs

154
Q

What is secretion?

A

Active transport from blood to filtrate

155
Q

How is secretion different from filitration?

A

It is selective via carrier proteins

156
Q

What is secretion important for?

A

K+ & H+ homeostasis in the collecting duct

157
Q

What decreases secretion of a molecule?

A

Molecules competing for carriers

158
Q

What is excretion?

A

Removal from the body

159
Q

What is urine?

A

Filtrate that leaves the collecting duct

160
Q

What is the equation for excretion?

A

Excretion = Filtration - Reabsorption + Secretion

161
Q

What is the renal handling of a substance?

A

An accounting of how much reabsorption and/or secretion of that substance occurs

162
Q

What is clearance of a substance?

A

Volume of plasma cleared of that substance per minute

163
Q

If clearance of X = GFR what is happening?

A

X is neither reabsorbed nor secreted

164
Q

If clearance of X is < GFR, what is happening?

A

Net reabsorption of X

165
Q

If clearance of X is > than GFR, what is happening?

A

Net secretion of X

166
Q

What is micturition?

167
Q

What occurs at rest regarding micturition?

A

-Somatic motor neurons to external sphincter tonically active (=contracted)
-Internal sphincter (smooth muscle) passively closed

168
Q

What is the micturition reflex and what activates it?

A

Stretch receptors in the bladder wall activate micturition reflex:
-parasympathetic neurons cause contraction of smooth muscle in bladder wall which mechanically opens internal sphincter
-somatic motor neurons to external sphincter inhibited (=no contraction)

169
Q

What is the voluntary inhibition of micturition?

A

The cerebral cortex stimulates an excitatory input to somatic motor neurons causing them to contract/close external sphincter to override reflex inhibition

170
Q

Why is Na+ the most important ECF solute?

A

Primary determinant of ECF volume

171
Q

What is Na+ in ECF controlled by?

A

Aldosteron, ANP, angiotensin II

172
Q

What is K+ controlled by?

A

Aldosterone

173
Q

What is K+ a major determinant of?

A

Resting Vm

174
Q

What does dysregulation of ECF osmolarity causes?

A

Hypo/hypertonic environment which causes the cell to swell or shrink

175
Q

What is ECF osmolarity controlled by?

A

Vasopressin & thirst

176
Q

What is ECF volume controlled by?

A

Regulating Na+

177
Q

What does dysregulation of ECF volume cause?

A

Alters MAP (hypertension/hypotension)

178
Q

ECF osmolarity & volume can change ______________.

A

Independently

179
Q

What is the cardiovascular response to changes in blood volume?

A

-Fast, neural control
-Can’t be sustained
-Can’t add/remove fluid

180
Q

What is the renal response to change in blood volume?

A

-Slow, mainly endocrine controlled
-Can remove fluid

181
Q

What is the behavioral response to changes in blood volume?

A

-Thirst/drinking
-Slow
-Can add fluid

182
Q

How is ECF osmolarity maintained?

A

-High EDF osmolarity stimulates thirst to intake fluid
-Varying urine concentration

183
Q

What are the 3 key features of controlling urine concentration?

A
  1. Filtrate entering collecting duct is dilute
  2. Collecting duct is surrounded by medullary interstitial fluid with osmotic gradient
  3. Amount of reabsorption is regulated by altering permeability of collecting duct
184
Q

What is the osmotic gradient in the collecting duct?

A

-Reabsorbs water from collecting duct by osmosis
-Filtrate (becoming urine) traveling deeper through medullar becomes progressively more concentrated

185
Q

What does the Loop of Henle function as in the production of interstitial osmotic gradient?

A

Countercurrent multiplier: self-reinforcing = “multiplier” effect

186
Q

What does the thick portion of the ascending limb do?

A

-Actively reabsorbs Na+ & Cl- into interstitial fluid
-Not permeable to water
-Increases osmolarity of interstitial fluid
-Decreases osmolarity of filtrate as it ascends towards cortex

187
Q

What does the descending limb do?

A

-Passive reabsorption of water into interstitial fluid
-Impermeable to solutes
-Decreases osmolarity of interstitial fluid
-Increases osmolarity of filtrate progressively as it descends into medulla

188
Q

What is the vasa recta?

A

Peritubular capillaries associated with loop of Henle

189
Q

What does the vasa recta do?

A

-removes water & solutes reabsorbed by loop of Henle
-has similar osmotic gradient

190
Q

What is vasopressin?

A

Antidiuretic hormone secreted from the posterior pituitary

191
Q

What does vasopressin do?

A

-Causes collecting duct cells to insert aquaporin channels in membrane to increase. collecting duct permeability to water

192
Q

What happens to vasopressin if ECF osmolarity is too high?

A

Increase vasopressin secretion to increase permeability leads to more concentrated urine

193
Q

What happens to vasopressin if ECF osmolarity is too low?

A

Decr. in vasopressin secretion decreases permeability to dilute the urine

194
Q

What is the stimulus causing vasopressin secretion?

A

-An incr. in ECF osmolarity causes osmoreceptors in hypothalamus to shrink
-decr. blood pressure
-decr. in blood volume
-Angiotensin II

195
Q

What is Aldosterone?

A

Secreted by adrenal cortex and acts on principal (P) cells of distal nephron to causes incr. of Na+ reabsorption and K+ secretion

196
Q

What is the secretion of Aldosterone stimulated by?

A

Decr. blood pressure via RAAS pathway & incr. K+

197
Q

What is the Renin-Angiotensin-Aldosterone System (RAAS)?

A

An endocrine pathway promoting an incr. in MAP

198
Q

What is angiotensinogen?

A

Inactive plasma protein

199
Q

What is renin?

A

Enzyme secreted by granular cells that converts angiotensinogen to angiotensin I

200
Q

What is renin secreted in response too?

A

-Decr. MAP dectected by granular cells
-Decr. of GFR and decr. of NaCl detected by macula dense
-Decr. MAP through CVCC to incr. sympathetic input

201
Q

How is angiotensin I converted to angiotensin II?

A

Using angiotensin converting enzyme

202
Q

What does angiotensin II do?

A

Raises MAP by:
-incr. aldosterone secretion to incr. Na+ reabs. to incr. ECF volume
-incr. vasopressin secretion to incr. H2O reabs. to incr. ECF volume
-incr. thirst to incr. ECF volume

203
Q

How does angiotensin interact with the CVCC?

A

-incr. HR, SV, TPR
-incr. vasoconstriction
-incr. Na+ reabs.

204
Q

How does the atrial natriuretic peptide increase blood volume?

A

-in response to stretch of atria, indicates incr. of blood volume

205
Q

How does the atrial natriuretic peptide decrease blood volume and MAP?

A

-decr. vasopressin, renin, and aldosterone
-CVCC: decr. HR, SV, TPR
-vasodilate afferent arteriole to incr. GFR
-decr. Na+ reabs.

Human Physiology (10 decks)

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