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1

What are the 2 main period of the cardiac cycle and what do they do?

systole: ventricle contraction
diastole: ventricle relaxation

2

Why do valves open passively?

due to pressure gradients

3

What valves open when atrial pressure is greater than ventricular pressure?

AV

4

What valves open when ventricular pressure is greater than atrial pressure?

semilunar

5

What are the 4 phases of the cardiac cycle?

1. ventricular filling
2. isovolumetric ventricular contraction
3. ventricular ejection
4. isovolumetric ventricular relaxation

6

What is the first phase of the cardiac cycle?

ventricular filling: when atria pressure is greater than the ventricles and AV valves are open

7

What is the second phase of the cardiac cycle?

isovolumetric ventricular contraction: increases pressure due to ventricle contraction, AV and semilunar valves are closed and no blood enters or exits. the ventricle

8

What is the third phase of the cardiac cycle?

ventricular ejection (pumping): ventricle pressure is greater than in the arteries, semilunar valves open

9

What is the fourth phase of the cardiac cycle?

isovolumetric ventricular relaxation: ventricle can relax which decreases pressure, AV and semilunar valves are closed and no blood enters or exits the ventricle

10

What is an active phase?

when no atria or ventricles contract

11

What is a passive phase?

when atria contract

12

When is heart sound 1 between?

atrial systole and isovolumetric ventricular contraction

13

When is heart sound 2 between?

ventricular ejection and isovolumetric ventricular relaxation

14

What is the fourth phase of the cardiac cycle?

isovolumetric ventricular relaxation: ventricle can relax which decreases pressure, AV and semilunar valves are closed and no blood enters or exits the ventricle
- pressure is less than aorta so aortic valve closes

15

When is ventricular filling passive until?

until the atrium contracts

16

How long does ventricular systole last and how long is the entire cycle?

systole: 0.3 seconds
entire: 0.8 seconds
(therefore diastole is 0.5 seconds)

17

What makes the sound "lubb"?

the closure of the tricuspid and mitral valves at the beginning of systole (AV valve)

18

What makes the sound "dubb"?

the closure of the aortic and pulmonary semilunar valves at the beginning of diastole

19

What is the dicrotic notch?

a brief rise in aortic pressure caused by back flow of blood rebounding off semilunar valves (closure of aortic valve at the end of systole)

20

What is systolic pressure?

the pressure in the aorta in the first phase (ventricles to aorta)

21

What is diastolic pressure?

the lowest pressure in the aorta when blood leaves it

22

What makes the sound "lubb"?

the closure of the tricuspid and mitral valves at the beginning of systole (AV valves close simultaneously)
- soft sound

23

What makes the sound "dubb"?

the closure of the aortic and pulmonary semilunar valves (SL valves simultaneously) at the beginning of diastole
- louder sound

24

What does the aorta do during systole/diastole?

stores E during systole as the walls expand then releases it during diastole as the walls recoil inwards

25

What is end diastolic volume?

the volume of blood left in the ventricle at the end of diastole = 130ml

26

What is end systolic volume?

the volume of blood left in the ventricle at the end of systole = 60ml

27

What is stroke volume?

the volume of blood ejected from the ventricles each cycle = 70ml (1 heart beat)
(equal to end diastolic volume minus end systolic volume)

28

What is the ejection fraction?

stroke volume / end diastolic volume = 70/130 = 0.54 (54%)

29

Why does the heart make sounds?

its due to turbulent flow when the valves close

30

What is cardiac output?

the volume of blood pumped by each ventricle per minute (= stroke volume x heart rate)
- affected by animal size, is 8% of body weight (higher for larger animals)

31

What is an average cardiac output?

5 liters/min at rest

32

What is an average amount of heart beats per minute?

about 72-75 ish

33

What is extrinsic regulation?

the regulation of any organ function from factors originating outside the organ (neural and hormonal regulation)

34

What is intrinsic regulation?

the regulation of an orgran function by factors originating within the organ (autoregulation)

35

What does the ANS innervate?

the conduction system and the heart muscle (myocardium) SNS

36

Which system affects the contraction of the heart?

SNS

37

What is the SA node intrinsic firing rate

100 AP/min

38

What hormones increase sympathetic activity (excitatory)

epinephrine and nerves

39

Which receptors receive the signal that sympathetic activity have increased?

beta 1

40

What opens when beta 1 receptors are activated?

calcium funny (If) channels

41

What receptors generate a resting state?

acetylcholine on M receptor (parasympathetic - decreases heart rate to rest)

42

Which receptors respond to increased parasympathetic activity and where?

muscarinic cholinergic receptors in the SA node

43

What nerve through which does the parasympathetic system activity increases?

vagus

44

What do muscarinic receptors do?

increase open state of potassium channels and closed state of calcium channels

45

What do open potassium and closed calcium channels do?

decreases rate of spontaneous depolarization and hyperpolarizes cell, therefore decreasing heart rate

46

How does parasympathetic activity affect levels of depolarization and repolarization?

Decreases depolarization, increases repolarization

47

How does sympathetic activity affect levels of depolarization and repolarization?

increases depolarization, decreases repolarization

48

How does sympathetic activity affect AV node?

increases conduction velocity through the nerve

49

How does parasympathetic activity affect AV node?

decreases conduction velocity through the nerve

50

What does epinephrine do (x2) and where is it released from?

increases frequency of action potentials at the SA node and increases velocity of AP conduction through the cardiac muscle fibers (same effect as SNS) -- released by the adrenal gland

51

What hormones increase heart rate (force of contraction)?

glucagon, T3, T4 and insulin
- T3+T4 = thyroid hormones

52

How does glucagon increase heart rate?

it opens funny and calcium channels

53

What 3 factors affect stroke volume?

1. ventricular contractility (the force)
2. end diastolic volume
3. afterload

54

What is afterload?

the resistance that ventricles encounter to pump blood into arteries

55

What are the 2 extrinsic controls of stroke volume?

1. sympathetic drive to ventricular muscle fibers
2. hormonal control

56

What is the 1 intrinsic control of stroke volume?

changes in end diastolic volume

57

Whats a special feature of ventricles?

they never completely empty of blood

58

How do you increase cardiac contractility?

when norepinephrine binds to beta 1 adrenergic receptors in contractile cells (due to sympathetic innervation), which increases it
- parasympathetic innervation ain't important/significant

59

What 4 things affect ventricular contractility?

1. opening of calcium channels on the sarcolemma
2. enhancing the release of calcium from the sarcoplasmic returuclm (SR)
3. increasing the rate of ATPase activity and cross bridge cycling
4. enhancing the rate of calcium-ATPase (pump) activity on the SR and reuptake of calcium

60

What does protein kinase do?

increases calcium binding (affecting cross bridge cycle binding)

61

What 4 things increase when sympathetic activity is increased?

- epinephrine release
- strength of contraction
- rate of contraction
- rate of relaxation (relaxation period is shorter)

62

What are pressure gradients?

they drive flow from high pressure to low pressure

63

How is mean arterial pressure determined?

its the pressure of the aorta - 85-90 mmHg

64

What type of system is the circulatory system?

a closed system

65

What is pressure?

the force exerted by blood (from the left ventricle)

66

Flow rate is proportional to what?

directly proportional to the difference between the pressures at the 2 ends of the pipe and inversely proportional to the resistance of the pipe

67

What is bulk flow?

flow due to pressure gradients

68

What must exist to maintain blood flow?

a gradient throughout the circulatory system

69

What is a pressure gradient?

driving force of fluid from high to low pressure (aka the pressure in pulmonary arteries minus pressure in pulmonary veins)
- greater in systemic than pulmonary circuits (but more resistance in pulmonary cause shorter distance)

70

What is central venous pressure?

the pressure of the vena cava, 0mmHg

71

What is the amount of flow comparing systemic vs pulmonary circuits

they receive equal flow

72

What is a pressure gradient?

driving force of fluid from high to low pressure (aka the pressure in pulmonary arteries minus pressure in pulmonary veins)
- greater in systemic than pulmonary circuits (but less resistance in pulmonary cause shorter distance)

73

What 3 factors affect resistance to flow?

1. radius of vessel
2. length of vessel
3. viscosity of fluid (=n)

74

Which factor affects the length of the vessel

age is the only one

75

What creates higher resistance?

longer vessels

76

What is vasoconstriction?

the narrowing of arterioles and therefore increasing resistance

77

What is vasodilation?

the widening of arterioles and therefore decreasing resistance

78

What is total peripheral resistance?

the combined resistance of all blood vessels within the systemic circuit

79

What does resistance depend on?

resistance across a network of blood vessels depend on resistance of all vessels

80

What is microcirculation/

the vessels cannot be seen with our eyes, only with microscope (arterioles, capillaries and venules)

81

What do arteries and veins do?

arteries: carry blood away from the heart
veins: carry blood towards the heart

82

Where are endothelial cells located?

they line the inner layer of the blood vessels

83

What is collagen?

a tensile protein, enables blood vessels to withstand pressure (fibrous connective tissue)

84

What is elastin?

a stretchable protein, enables blood vessels to expand or contract (elastic connective tissue)

85

What are arteries?

they have the thickest wall, are stiff and have highly elastic pressure reservoirs (large diameter, little resistance) -- walls contain elastic and fibrous tissue

86

What are arterioles?

they are muscular, well innervated blood vessels that serve as a contractile vessel
- connect arteries to capillaries or metarterioles
- part of microcirculation

87

What are arteries?

they have the thickest wall, are stiff and have highly elastic pressure reservoirs (large diameter, little resistance) -- walls contain elastic and fibrous tissue

88

What are venules?

thin walled blood vessels that contain some smooth muscle, their only function is to return blood to the heart

89

What are veins?

thin walled blood vessels with a large internal diameter, are fairly muscular, highly distensible and can store blood in the body for use (have internal valves)

90

What is the basal lamina?

a thin extracellular layer that lies underneath epithelial cells and separates them from other tissues

91

What is the pericyte?

a stem cell that regenerates smooth muscle cells

92

What is an adipocyte?

a cell that stores fat

93

What are muscular arteries?

medium sized arteries that contain layers of smooth muscle allowing for involuntary control of vessel diameter, controlling blood flow -- smooth muscle regulates radius

94

What is compliance?

the ability of a vessel to distend and increase volume with increasing transmural pressure (used as an indication of arterial stiffness)

95

Where is systolic blood pressure at its max?

in the aorta due to ejection of blood into it (diastolic is minimum in it too)

96

What happens to the arteries during diastole/systole?

systole: expand
diastole: recoil

97

Why is arteriole blood pressure never 0?

due to elastic recoil

98

What is arterial blood pressure?

the pressure in the aorta

99

What are metarterioles?

short vessels that link arterioles and capillaries; also act as bypass channels for times when precapillary sphincters constrict

100

What is systolic blood pressure?

the maximum pressure due to the ejection of blood into the aorta

101

What is diastolic blood pressure?

minimum pressure that isn't 0 due to elastic recoil

102

What regulates radius / resistance in arterioles?

rings of smooth muscle (have alpha adrenergic receptors)

103

What provides greatest resistance to blood flow?

arterioles

104

What are precapillary sphincters?

close off capillaries in response to loca signals

105

What is arteriolar tone?

radius of the arteriole independent of extrinsic influences; typically, partially contracted

106

What does mean arterial pressure depend on?

on TPR which depends on the radius of arterioles

107

What is phosphatidyl inositol triphosphate?

the system that norepinephrine reacts with alpha adrenergic receptors on, causing vasoconstriction

108

What does norepinephrine bind to?

alpha adrenergic receptors

109

What does epinephrine bind to and what does it cause?

alpha: vasoconstriction
beta2: vasodilation

110

What is angiotensin 2?

synthesized from angiotensinogen and is responsible for vasoconstriction
- increases MAP

111

Where is angiotensinogen synthesized?

in the liver

112

What does renin do?

converts angiotensinogen to angiotensin 1

113

What does ACE (angiotensin-converting enzyme) do?

converts angiotensin 1 to angiotensin 2

114

What is another name for ADH?

vasopressin

115

What does ADH do?

comes from the hypothalamus (posterior pituitary), increases water reabsorption by the kidneys (minimizes water loss) which causes vasoconstriction
- increases MAP

116

Where does epinephrine come from and what effect does it have on MAP?

comes from the adrenal medulla (hormone) and increases MAP

117

What are capillaries?

sites of exchange between blood and tissue
- very close to cells
- pores
- slow blood velocity
- small diffusion barrier

118

Where are capillaries found?

in networks called capillary beds

119

What moves through pores between endothelial cells of capillaires?

protein free plasma

120

What are continuous capillaries?

most common capillaries, small gaps between endothelial cells that allow small water-soluble/lipid-soluble (fatty acids, steroids) through.

121

Where are continuous capillaries located?

located in skin, most nervous/connective tissue, muscle tissue

122

What are fenestrated capillaries?

capillaries with large gaps between endothelial cells forming pores/fenestrations; allow proteins and sometimes blood cells to move through.

123

Where are fenestrated capillaries located?

located in kidneys, endocrine glands, small intestine

124

What are sinusoidal capillaries?

capillaries that serve as discontinuous sheets of endothelium with very large pores; allow large molecules (proteins and cells) through capillary walls.

125

Where are sinusoidal capillaries located?

located in liver, lymphoid organs, bone marrow, spleen

126

What are sinusoids?

large blood filled spaces that function in the exchange of substances between blood and tissue

127

Where does blood cells move through in sinusoidal caps?

bone marrow and spleen

128

What 2 liver proteins are released into the blood through sinusoidal caps?

albumin and clotting factors

129

What are metarterioles?

intermediates between arterioles and capillaries that directly connect arterioles with venules
- shunts to bypass capillaries

130

What happens when metarterioles contract and relax?

contract: increases blood flow through capillaries
relax: decreases blood flow through capillaries

131

What are precapillary sphinctors?

rings of smooth muscle that surround capillaries on the arteriole end
- contract and relax due to local factors only

132

What happens when precapillary sphinctors contract and relax?

contract: constricts capillary and restricts blood flow
relaxes: increases blood flow

133

What pauses relaxation (vasodilation)?

CO2 and pH

134

What causes contraction (vasoconstriction)?

oxygen

135

What is a metabolite?

a specific product of a substance, formed by chemical processes in the body

136

What is the most common mechanism of exchange across capillary walls?

diffusion

137

What is transcytosis?

the movement of exchangeable proteins into, across, and then out of a cell

138

What is mediated transport?

the transport of specific proteins which takes place in the brain

139

What are the 4 pathways of exchanging material across a capillary wall?

1. transcytosis (pinocytosis/endocytosis)
2. diffusion (pressure driven bulk flow)
3. diffusion via junctions and fenestrations
4. diffusion across cells (lipid soluble molecules)

140

Filtration vs absorption

filtration: movement out of a capillary
absorption: movement into a capillary

141

What is the purpose of bulk flow?

to maintain balance between interstitial fluid and plasma (distribute ECF)

142

What is pinocytosis?

a type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

143

What is the hydrostatic pressure gradient?

forces due to fluid

144

What is osmotic pressure?

osmotic force exerted on water by non-permeating solutes (proteins)

145

What is oncotic pressure?

osmotic force of proteins

146

What are starling forces?

forces that drive movement of fluid into and out of capillaries

147

What is capillary hydrostatic pressure (Pcap)?

pressure due to the hydrostatic pressure of fluid inside the capillary (higher pressure at the arteriole end vs the venous end)

148

What is interstitial fluid hydrostatic pressure (Pif)?

pressure due to the hydrostatic pressure of fluid outside of the capillary

149

What is capillary osmotic pressure (Picap)?

pressure due to the presence of non-permeating solutes inside the capillary

150

What is interstitial fluid osmotic pressure (Piif)?

pressure due to the presence of non-permeating solutes outside the capillary

151

What does Pcap favour?

filtration

152

What does Pif favour?

reabsorption

153

What does Picap favour?

reabsorption

154

What does Piif favour?

filtration

155

What is the main determinant of oncotic pressure?

albumin (a protein)

156

What does the hydrostatic pressure gradient favour?

reabsorption

157

What does the osmotic pressure gradient favour?

reabsorption

158

What is net filtration pressure?

filtration pressure-absorption pressure

159

What does the arteriole end favour in net filtration?

filtration (more of it across the capillary)

160

What does the venous end favour in net filtration?

absorption

161

What does the lymphatic system do?

picks up excess filtrate and returns it to circulation

162

How much net filtration is there per day (amount of fluid left unabsorbed)?

3L

163

How much fluid is filtered in the body per day?

20L

164

What are venules?

- smaller than arterioles
- connect capillaries to veins
- single layer of endothelium and are porous (some exchange of material between blood and interstitial fluid)

165

What is the lymphatic system (open or closed)?

open

166

What is the lymphatic system composed of?

vessels, nodes and organs

167

What do vessels do?

are involved in returning excess filtrate to circulation

168

What is the colour of lympth?

yellow

169

What do lymphatic capillaries do and what do they have?

collect excess fluid from capillaries that is then returned to the veins (have valves)

170

Where does lymph enter?

enters veins near jugular veins and then into the right atrium

171

Which way does lymph move?

from capillaries to veins

172

What do lymph nodes do?

contain macrophages/immune cells that filter lymph flowing through

173

What is the size of veins?

have a large diameter but with thin walls

174

What are peripheral veins?

all veins outside the thoracic cavity

175

What are central veins?

all veins within the thoracic cavity

176

Where are there valves on veins?

in the peripheral veins, NOT central veins

177

What has a larger diameter, venae cavae or the aorta?

venae cavae (30 vs 12.5)

178

What is compliance?

property of veins that enables them to expand with little change in pressure

179

What is another vein function?

as a blood reservoir (readily available so that it can shift to the arterial side of the circulation)

180

What holds more blood: arteries or veins?

veins (at a given pressure)

181

What is a respiratory pump?

pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand

182

How will inspiration affect the pressure in the thoracic and abdominal cavities?

decreases pressure in thoracic cavity, increases pressure in abdominal cavity

183

Pressure on veins in the abdominal cavity due to inspiration creates a gradient that favours blood movement to where?

thoracic cavity

184

What is central venous pressure?

venous blood pressure within the right atrium that influences the pressure in the large peripheral veins

185

What is venous return?

the amount of blood returned to the heart by the veins

186

How will expiration affect the pressure in the thoracic and abdominal cavities?

increases in thoracic, decreases in abdominal

187

What does expiration favour?

movement of blood to abdominal veins

188

Backwards flow to the abdomen is prevented by what?

closure of valves in the abdominal cavity

189

How does an increase in blood volume affect venous pressure?

it increases it

190

How does an decrease in blood volume affect venous pressure?

it decreases it

191

How is blood pressure regulated?

through blood volume

192

What is venomotor tone?

smooth muscle tension in the veins; caused by contraction of smooth muscle in the wall of the vein, which then constricts it

193

How does a decrease in blood volume affect the body?

it activates mechanisms in the kidneys to lower water output elimination through urine (maintains blood volume and venus pressure)

194

Where are alpha adrenergic receptors located?

receptors present in the smooth muscle of the walls of veins

195

Smooth muscles in the walls of veins is innervated by what?

by the SNS

196

What causes venous constriction?

when norepinephrine stimulates the contraction of smooth muscle

197

What causes increased cardiac output?

an increase in venous pressure caused by increase in venomotor tone, causing an increase in SV

198

What is blood?

a vehicle for transport

199

What is the average blood volume in the body?

8% of body weight

200

What are the 4 components of blood?

plasma, erythrocytes (RBC), leukocytes (WBC) and platelets

201

What is serum?

plasma from which fibrinogen and other clotting proteins have been removed

202

What is most dense in blood?

plasma

203

What is hematocrit?

the fractional contribution of erythrocytes to the blood (aka hct)

204

What proteins are in blood?

albumins (most concentrated), globulins and fibrinogen

205

What 3 things is plasma composed of?

mostly water, then proteins then electrolytes (mostly Na and Cl, minimal H, HCO3, K and Ca)
- nutrients, wastes, dissolved gasses and hormones

206

What colour is plasma?

a pale yellow

207

What dissolved gas is most concentrated in plasma?

nitrogen

208

What is synthesized in the liver?

albumins and fibrinogen

209

What is synthesized by lymphocytes?

globulins

210

What does fibrinogen get converted to?

to fibrin in the clotting process

211

When are lymphocytes more populated?

when animals have more stomachs

212

Animals with less stomachs have more what?

neutrophils

213

What is the average blood pH and that is ideal for protein/enzyme function?

7.4

214

What does albumin do?

it is a major contributor to plasma oncotic pressure and is a carrier for steroids, fatty acids and thyroid hormones

215

What is fibrinogen synthesized by?

the liver

216

What is the key to blood clot formation?

fibrinogen

217

What are alpha and beta globulins?

produced by the liver, they are carriers for lipids, steroids and other compounds and act as:
- clotting factors
- enzymes
- precursor proteins (angiotensinogen)

218

What are gamma globulins?

immunoglobulins that are part of the immune system

219

What do lymphocytes do?

produce specific immune responses directed against invaders

220

What do monocytes do?

develop into macrophages after migrating into tissues

221

What do neutrophils do?

they are mobile phagocytes (bacteria killing) that ingest foreign substances and pathogens
- red and blue staining
- predominant white blood cell

222

What do eosinophils do?

produce toxic compounds directed against invading pathogens
- red staining

223

What do basophils do?

aka mast cells, defend against large parasites by releasing toxic substances
- contribute to allergic reactions (histamine/heparin)
- blue staining

224

What is the shape of an erythrocyte and its name?

biconcave disk -- has a large surface area and favours diffusion to enhance gas exchange
- lifespan is longer in larger animals

225

Why are erythrocyctes flexible (membrane)?

due to spectrin (forms hexagonal arrangements for maintenance and integrity)

226

What is the function of erythrocytes and what are they composed of?

are literally a bag of enzymes and hemoglobin (not efficient) -- they transport oxygen and CO2

227

How is glucose metabolized in RBC's and what is created?

metabolized by glycolysis yielding lactate which is excreted into the blood

228

How do red blood cells produce ATP?

glycolysis

229

What is necessary for generating energy needed to fuel active transport mechanisms involved in maintaining proper ionic concentrations within a red blood cell

glycolytic enzymes

230

What is essential for the transport of carbon dioxide?

carbonic anhydrase

231

What is a hemoglobin molecule composed of?

globin + 4 heme groups

232

What is hemoglobin?

an iron-containing protein in red blood cells that reversibly binds oxygen.

233

What is carbonic anhydrase?

its the enzyme inside of red blood cells that is essential for the transport of CO2, adds it to H20 to form H2CO3 for carrying

234

What is a globin?

4 chains of polypeptides

235

What is a heme?

an iron containing group

236

What 3 things can hemoglobin bind to?

CO, CO2 and H

237

What colour is oxygenated hemoglobin?

bright red (cause its in ferrous form)

238

What colour is deoxygenated hemoglobin?

dark red

239

Where do erythrocytes get produced and through what process?

in red bone marrow through erythropoiesis

240

Where do erythrocytes get filtered?

by the spleen and liver

241

What do macrophages do?

engulf old RBCs at the end of their lifespan through phagocytosis

242

What are hematopoietic stem cells?

cell in the bone marrow that gives rise to all types of blood cells

243

What is erythropoietin?

stimulates erythrocyte synthesis; secreted from kidneys under conditions of low oxygen levels in the blood flowing to the kidneys
- produces hemoglobin

244

What 3 substances are required for erythrocyte production?

folic acid, iron and vitamin B12

245

What does a lack of iron cause?

ammonia

246

Why are folic acid and vitamin B12 requirements?

for DNA replication and cell proliferation

247

What filters and removes old erythrocytes?

the spleen

248

What metabolizes byproducts from the breakdown of erythrocytes?

the liver

249

When is hemoglobin catabolized and by what?

after phagocytosis of red blood cells in the spleen by macrophages

250

What is heme turned into after iron is removed?

bilirubin (goes to the liver for further metabolism)

251

Where are products of bilirubin catabolism secreted?

in bile to the intestinal tract or released into the bloodstream and excreted in urine

252

How is iron transported in blood and where does it go?

bound to transferrin (from GI or liver to bone marrow)

253

Iron stored is bound to what and where is it (x3)?

bound to ferritin in the liver, spleen and small intestine

254

What are platelets?

cell fragments produced in the bone marrow from megakaryocytes; have no nucleus, but possess mitochondria, smooth ER, granules

255

What do platelets do?

stop blood loss, act as immune cells + mediators of inflammatory response

256

What are granules?

membrane bound vesicles filled with enzymes and proteins

257

What are leukocytes?

they function in defense of the body (immune system - defend against pathogens, identify and destroy cancer cells and the phagocytosis of debris from dead or injured cells)

258

Where are leukocytes found?

the bloodstream and in body tissues

259

What is a pressure gradient?

the force for air flow, created by changes in alveolar pressure

260

What are the 3 granulocytes (cytoplasmic granules)?

neutrophils, basophils and eosinophils

261

What are agranulocytes (no cytoplasmic granules)?

monocytes and lymphocytes

262

What 2 factors determine inter-alveolar pressure?

quantity of air and volume

263

What is a blood smear stained with and what does it reveal?

wrights stain and reveals different leukocytes

264

What does heparin do?

prevents blood clotting (released by basophil)

265

When is intra-alveolar pressure 0?

when air flow stops

266

What does histamine do?

dilates blood vessels (released by basophil)

267

What are monocytes?

phagocytes that make up a small portion of leukocytes, become macrophages

268

What are wandering macrophages?

mobile cell moving throughout the alveoli, ingesting foreign particles

269

What are fixed macrophages?

stationary phagocytic cell that engulfs cell debris and pathogens

270

What are lymphocytes?

agranulocyte. 30% of leukocytes and 99% of interstitial fluid cells;

271

What are the 3 types of lymphocytes?

1. b lymphocytes (b cells)
2. T lymphocytes (t-helper cells)
3. null cells / natural killer cells

272

What are b cells?

associated with antibodies and becomes a plasma cell upon contact with an antigen
- have proteins on their membrane

273

What cell lacks membrane proteins?

natural killer cells

274

What are Cytotoxic T cells?

they directly damage foreign cells and contact+kill virally infected, mutant or transplanted cells
- have proteins on their membrane

275

How do T cells kills bad cells?

their secretory products form pores in the target cell membrane and water enters and they die

276

What are natural killer cells?

attack virus infected cells and cause lysis (early immune response)

277

What is a plasma cell?

secretes immunoglobulin antibodies that mark invaders for destruction

278

What class of antibody that marks bacteria for destruction?

IgM

279

What is the largest class of antibody and where is it found?

IgA -- found on all epithelial layers

280

What does a T cell become and how?

becomes a cytotoxic t cell upon contact with a foreign cell

281

What activates B and T cells?

interleukin-2

282

How is a Th cell activated?

by contact with a macrophage

283

What does interleukin activate (x4)?

TH, B, TC, and NK cells

284

What are perforins?

proteins that poke holes in pathogens and allow toxins to enter

285

What is a memory B cell?

a B cell that responds to an antigen more strongly when the body is reinfected with an antigen than it does during its first encounter with the antigen

286

What is external respiration?

exchange of oxygen and carbon dioxide between atmosphere and body tissues

287

What is the function of oxygen?

generation of ATP in mitochondria and oxidative phosphorylation

288

What is internal respiration?

oxidative phosphorylation

289

What is pulmonary ventilation?

movement of air into and out of the lungs

290

What is pulmonary capillaries?

site of exchange between lungs and blood

291

What are systemic capillaries?

site of exchange between blood and body tissues

292

What is bulk flow?

the movement of air based on pressure gradients

293

What does upper airways refer to?

air passages in the head and neck

294

What are the 3 air passages of the head and neck?

nasal cavities, oral cavity and the pharynx

295

What is the larynx?

the voice box, contains vocal cords

296

Where does the respiratory tract go from?

in airways from pharynx to lungs

297

What is the respiratory tract composed of (x3)?

larynx, conducting and respiratory zone

298

Why is there less space on the left lung?

cause of the heart

299

What is the smaller lobe called on the lungs?

cranial lobe (top)

300

What is the larger lobe called on the lungs?

caudal lobe (bottom)

301

How many lobes do the right and left lungs have?

right: 4 // left: 2

302

What are the left lobes of a bovine lung?

cranial and caudal

303

What are the right lobes of a bovine, pig and dog lung?

cranial, middle, caudal and accessory lobes

304

What are the left lobes of a dog lung?

bilobed cranial and caudal

305

What are the left lobes of a pig lung?

divided cranial and caudal

306

What are the 3 structures of the conducting zone?

trachea, bronchi and secondary bronchi

307

What is the conducting zone?

includes respiratory passageways; serves as air passageway (dead space volume), increases air temperature to body temperature, humidifies air by adding water vapor until it reaches 100% humidity, filters inspired air through trachea and bronchi to prevent viruses, bacteria, and inorganic particles from reaching alveoli

308

What are bronchi?

two short branches located at the lower end of the trachea that carry air into the lungs

309

What are secondary bronchi?

branches of the primary bronchi that lead to each lobe of the lung; also called lobar bronchi

310

What marks the end of conducting zone?

terminal bronchioles (0.5mm)

311

What is the difference between the conducting and respiratory zones?

thickness of walls (determines whether gas exchange occurs)

312

What are tertiary bronchi?

branches of the secondary bronchi that divide into bronchioles; also called segmental bronchi. 16-23 orders of branching

313

What are bronchioles?

smallest branches of the bronchi; diameter <1mm
- have elastic fibers and smooth muscles
- prevent collapsing and help change diameter

314

What is the respiratory zone?

respiratory bronchioles and alveoli; site of gas exchange between air and blood via diffusion

315

What do goblet cells do?

they produce mucus that contain immunoglobulins

316

What happens when diameter of airways decrease?

the number of passageways increase

317

What is dead space?

when air does not participate in gas exchange with blood in a region

318

What is a cross sectional area?

a surface or shape exposed by making a straight cut through something at right angles to the axis

319

How does cross sectional area react to division of the airways?

it grows larger

320

What are ciliated cells?

they move particles towards the mouth (mucus containing trapped particles out of the lungs into the pharynx)

321

What is the mucus escalator?

it prevents mucus from accumulating in the airways and clears trapped foreign matter

322

What occurs if mucus accumulates?

infection might occur (due to bacteria colonizing)

323

What allows the mucus elevatory to function properly?

the secretion of a watery saline layer beneath mucus

324

What are the largest producers of mucus?

submucosal glands

325

What are respiratory bronchioles?

they are branches of the terminal bronchioles that subdivide into several alveolar ducts

326

What are the 4 structures of the respiratory zone?

respiratory bronchioles, alveolar ducts, alveoli and alveolar sacs

327

What is the respiratory membrane composed of?

epithelial cell layer of alveoli and an endothelial cell layer of capillary

328

What covers the majority of alveolar surface?

type 1 alveolar cells (used for gas exchange)

329

What do type 2 alveolar cells do?

they secrete surfactant which prevents collapsing of alveoli

330

What are alveolar macrophages?

they engulf foreign particles and pathogens

331

What are alveolar pores?

they connect adjacent alveoli and allow air to flow between alveoli which allows equilibration of pressure within the lungs

332

What are alveoli?

sites of gas exchange, over which capillaries form a sheet for a rich blood supply

333

What are the 3 barriers for diffusion between air and blood (on respiratory membrane)?

basement membranes, capillary endothelial cells and type 1 cells

334

What is the chest wall?

an air tight structure that protects the lungs

335

What is the chest wall composed of?

the ribcage and sternum

336

What are the 3 muscles in the thoracic cavity?

diaphragm, internal intercostals and external intercostals

337

What is the pleura?

a membrane lineing the lungs and chest wall

338

What surrounds each lung?

the pleural sac

339

What is intrapleural space filled with?

intrapleural fluid (15ml) -- creates a negative pressure

340

What is the driving factor of bulk flow?

a pressure gradient (high to low)

341

How is the pressure in the lungs during inspiration?

less than the atmosphere

342

How is the pressure in the lungs during expiration?

greater than the atmosphere

343

What is atmospheric pressure?

the pressure caused by the weight of the atmosphere. ~760 mmHg at sea level, decreases as altitude increases, increases under water. other pressures are given relative to this

344

What is intra-alveolar pressure?

the pressure of the air in the alveoli; difference between this and atmospheric pressure drives ventilation

345

When is intra-alveolar pressure negative?

during inspiration

346

When is intra-alveolar pressure positive?

during expiration

347

What are the 4 primary pressures that are associated with ventilation?

Atmospheric, intra-alveolar, intrapleural and transpulmonary pressure

348

What is intrapleural pressure?

the pressure inside the pleural sac, always negative (under normal conditions) and less than intra-alveolar pressure -- varies with phase of respiration and keeps lungs extended

349

What drives ventilation?

the difference between intra-alveolar and atmospheric pressure

350

What is elasticity

property of lungs and chest wall that results in the negative pressure of the intrapleural pressure

351

What is transpulmonary pressure?

difference between intrapulmonary and intrapleural pressure; represents distending pressures across the lung wall

352

What does an increase in transpulmonary pressure cause?

increases distending pressure across the lungs, causing them to expand (increases volume)

353

What is a pneumothorax?

air in the pleural cavity caused by a puncture of the lung or chest wall

354

What is a pressure gradient?

force for air flow; created by changes in alveolar pressure

355

What 2 factors of alveoli determine intra-alveolar pressure?

quantity of air and volume

356

What determines the direction of air movement?

changes in alveolar pressure

357

What is the equation for flow?

atmos - intra-a / R

358

What happens to the alveolar pressure and volume when the lungs expand?

volume increases and pressure decreases

359

What happens to the alveolar pressure and volume when the lungs contract?

volume decreases and pressure increases

360

What is boyle's law?

an increase in volume will create a decrease in pressure and vv

361

When is intra-alveolar pressure 0?

When air flow stops

362

What do inspiratory muscles do and what are the 2?

they increase the volume of the thoracic cavity (diaphragm and external intercostals)

363

What do expiratory muscles do and what are the 2?

they decrease the volume of the thoracic cavity (internal intercostals and abdominal muscles)

364

How does expiration occur?

it is a passive process that happens when the lungs and chest wall recoil to their original positions once the inspiratory muscles stop contracting

365

What is active expiration?

when the contraction of expiratory muscles create a greater and faster decrease in volume of the thoracic cavity

366

How are oxygen. and carbon dioxide levels?

they remain relatively constant (move at the same time they are produced/consumed by cells)

367

What is the composition of air?

79% nitrogen and 21% oxygen

368

What is the pressure of nitrogen at 0% humidity?

600mmHg

369

What is the pressure of oxygen at 0% humidity?

160mmHg

370

What is the pressure of carbon dioxide at 0% air humidity?

0.23mmHg

371

What is the total pressure of a gas mixture equivalent to?

the sum of the pressures of the individual gases that make up the mixture

372

What is the pressure of nitrogen at 100% humidity?

563mmHg

373

What is the pressure of oxygen at 100% humidity?

149mmHg

374

What is the pressure of water at 100% humidity?

47mmHg

375

What is the pressure of CO2 at 100% humidity?

0.21mmHg

376

How do gas molecules exist?

in gas form or dissolved in liquid

377

What types of gases exert partial pressures and what are their partial pressures at eq?

vaporized and dissolved gases = equal at equilibrium

378

What is the solubility of oxygen like in water?

low solubility

379

What is the concentration of oxygen in water at 100mmHg partial pressure?

0.15mmoles/liter

380

What is the concentration of carbon dioxide in water at 100mmHg partial pressure?

3.0mmoles/liter

381

Is oxygen or carbon dioxide more soluble in water?

carbon dioxide is 20x more soluble in water and blood than oxygen

382

How do gases diffuse down gradients?

by partial pressure

383

Where is oxygen partial pressure = 100mmHg (x3)?

alveolar air, pulmonary veins and systemic arteries

384

Where is oxygen partial pressure less than or = 40mmHg?

in cells

385

Where is oxygen partial pressure 40mmHg (x2)?

pulmonary arteries and systemic veins

386

What is the partial pressure of oxygen in atmospheric air?

160mmHg

387

What is the partial pressure of CO2 in atmospheric air?

0.3mmHg

388

Where is the partial pressure of carbon dioxide 40mmHg (x3)?

alveolar air, pulmonary veins and systemic arteries

389

Where is the partial pressure of CO2 less than or equal to 46mmHg?

cells

390

Where is the partial pressure of CO2 46mmHg?

systemic veins and pulmonary arteries

391

What is the diffusion between alveoli and blood like?

very rapid since its a small diffusion barrier and very thin with a large SA

392

How long does it take for blood to equilibrate with alveolar air?

0.25 seconds

393

What concludes eq?

by the time blood has travelled 1/3 of the length of a capillary bed

394

How do oxygen and carbon dioxide diffuse?

oxygen: from blood to cells
carbon dioxide: from cells to blood

395

What is mixed venous blood?

a mixture of venous blood from the upper and lower extremities, complete

396

Where does venous blood get mixed and go to?

in the right ventricle and goes to the pulmonary artery

397

What is minute alveolar ventilation?

the volume of fresh air that reaches the alveoli each minute, similar to minute ventilation but air in anatomical dead space must be accounted for

398

What percentage of arterial blood oxygen is dissolved in plasma?

1.5%

399

What percentage of arterial blood oxygen is transported by hemoglobin?

98.5%

400

What is the law of mass action?

an increase in the concentration of the reactants drives the reaction to the right, resulting in the generation of more product

401

What is the max # of oxygen molecules that one hemoglobin can bind to?

4

402

How soluble is oxygen in plasma?

not very

403

Where is oxyhemoglobin formed and what is it?

oxygenated hemoglobin, formed in the lungs

404

Where is deoxyhemoglobin formed and what is it?

deoxygenated hemoglobin, formed in the tissues

405

How do you measure how much oxygen is bound to hemoglobin/

the saturation of hemoglobin

406

What is positive cooperativity?

the first substrate changes the shape of the enzyme allowing other substrates to bind more easily

407

How much oxygen does 1g of hemoglobin carry when 100% saturated?

1.34

408

What is 100% saturation?

a state in which all 4 binding sites on hemoglobin have oxygen bound to them

409

What are normal blood hemoglobin levels?

12-17gm/dL (150g/L)

410

What % of hemoglobin is saturated in venous blood?

75%

411

How much oxygen is released to the tissues?

250mL/min

412

What causes a rightward shift?

less loading of oxygen and more unloading

413

What causes a leftward shift?

more loading of oxygen and less unloading

414

How does high temperature affect oxygen loading?

causes a right shift

415

How do lower pH levels affect oxygen loading?

results in a right shift

416

What is the bohr effect

lower pH increases oxygen unloading

417

What happens when oxygen binds to hemoglobin?

certain amino acids in the protein release hydrogen ions

418

What happens when theres an increase in H+ ion concentration (decrease in pH)?

pushes the reaction leftward and oxygen dissociates (decreases the affinity of hemoglobin for oxygen)

419

What is the carbamino effect?

a decrease in the affinity of hemoglobin (conformation change) for oxygen when carbon dioxide binds to hemoglobin (caused by increased metabolic activity)

420

What is carbaminohemoglobin?

the compound formed by the union of carbon dioxide and hemoglobin (has a lower affinity for oxygen than normal hemoglobin)

421

What is 2,3-DPG?

is produced in red blood cells under conditions of low oxygen such as anemia and high altitude (decreases affinity of hemoglobin for oxygen, therefore enhancing oxygen unloading)

422

What is the synthesis of 2,3-DPG inhibited by?

oxyhemoglobin

423

What does hemoglobin have a greater affinity for (carbon monoxide or oxygen)

CO than O2 (that's why it can kill you)

424

What does carbon monoxide do?

it prevents oxygen from binding to hemoglobin

425

Is CO2 concentrations higher in systemic arterial or venous blood?

in systemic venous blood

426

How much carbon dioxide transported is dissolved in plasma?

5-6%

427

How much carbon dioxide transported is bound to hemoglobin?

5-8%

428

Is CO2 more soluble in plasma or oxygen?

plasma

429

How is CO2 transported in plasma?

erythrocytes convert it to bicarbonate (86-90% transported)

430

What is carbonic anhydrase?

the fastest enzyme to convert CO2 and water to carbonic acid

431

What is the law of mass action/

an increase in carbon dioxide causes an increase in bicarbonate and hydrogen ions

432

Where does chloride go in the erythrocyte when CO2 goes to the alveoli

goes in (VV)

433

What is a chloride shift?

the movement of chloride ions into the RBCs as H ions move out to maintain the electrochemical eq

434

How does the urinary system regulate plasma ionic composition?

by regulating uptake/excretion of: Na, K, Ca, Mg, Cl, bicarbonate, H and phosphates

435

How does the urinary system regulate plasma volume and blood pressure?

by controlling the rate at which water is excreted in the urine, the kidneys regulate plasma volume and blood pressure

436

How does the urinary system regulate plasma osmolarity?

by regulating solute concentration (osmolarity) by regulation of water excretion

437

How does the urinary system regulate plasma pH

by regulating concentration of bicarbonate and hydrogen ions in the plasma they contribute to regulation of blood pH

438

How does the urinary system remove metabolic waste products and foreign substances from plasma?

the kidneys excrete waste and undesirable substances in the urine (ex. urea (proteins) / uric acid (nucleic acids) )

439

What are the 3 foreign substances that kidneys excrete in urine?

drugs, feed additives and pesticides

440

What does the secretion of erythropoietin stimulate?

erythrocyte production (RBC by bone marrow)

441

What does the secretion of renin do?

it raises blood pressure by influencing vasoconstriction -- necessary for the production of angiotensin 2

442

What is calcitriol?

the active form of vitamin D that gets activated by the kidneys -- regulates calcium and phosphorus metabolism (synthesized in skin)

443

What is gluconeogenesis?

formation of glucose from noncarbohydrate sources; supplies glucose to plasma by degrading certain amino acids and glycerol

444

What 6 things does the urinary system consist of?

2 kidneys, 2 ureters, a urinary bladder and the urethra

445

What do kidneys do?

form urine

446

What do ureters do?

transport urine from the kidneys to the bladder

447

What does the bladder do?

stores urine

448

What does the urethra do?

excretes urine from the bladder outside of the body

449

What lines the abdominal cavity?

a membrane called the peritoneum

450

What does retroperitoneal mean?

something located between the peritoneum and abdominal wall

451

What are renal arteries?

the 2 branches of the abdominal aorta that supply the kidneys

452

What is the renal hilus?

a location where renal arteries enter the kidney and renal veins exit the kidney

453

Where are most abdominal organs located?

they are enclosed within the peritoneum

454

What is the capsule?

a tough, fibrous connective tissue that surrounds the outside of the kidney

455

What is the renal cortex?

a reddish brown outer layer of the kidney

456

What is the renal medulla?

the inner region of the kidney

457

What is the renal pyramid?

a triangular shaped division of the medulla of the kidney -- also aka papillae

458

What do collecting ducts do?

several nephrons share a collecting duct which serve to carry urine to the renal pelvis; originate at the tips of papillae

459

Where do collecting ducts drain to?

minor calyces

460

The convergence of minor calyces form what?

2-3 major calyces

461

Where do major calyces drain to?

the renal pelvis

462

Polylobed vs monolobed

monolobed means there is one lobe on the kidney (ex. pigs, sheep, horses, dogs an cats) whereas polylobed means there are multiple (ex. chicken or cattle)

463

What are nephrons?

the functional unit of the kidney (over a million of them in the kidney)

464

What is the renal corpuscle composed of?

bowmans capsule and the glomerulus

465

What is bowmans capsule?

a spherical structure at the inflow end of the renal tubules (where urine is formed)

466

What is the glomerulus?

a network of capillaries that bring blood to the nephron

467

What are renal tubules?

a system of tubes into which filtered fluid in the nephron flows

468

What occurs at the renal corpuscle?

where blood is filtered and where filtrate originates

469

What is the proximal tubule?

In the vertebrate kidney, the portion of a nephron immediately downstream from Bowman's capsule that conveys and helps refine filtrate.

470

What is the proximal convoluted tubule?

first section of the renal tubule that the blood flows through; reabsorption of water, ions, and all organic nutrients

471

What is the proximal straight tubule?

commonly referred to as the thick descending limb of the loop of henle, descends into the medulla

472

What is the loop of henle?

section of the nephron tubule that conserves water and minimizes the volume of urine

473

What is the descending limb?

the limb of the loop of Henle that carries fluid from the cortex towards the medulla of the kidney

474

What is the thin ascending limb?

receives concentrated fluid from descending limb and allows diffusion of Na+ and Cl- into the interstitial fluid

475

What is the thick ascending limb?

impermeable to water, active solute transport

476

What is the distal convoluted tubule?

between the loop of Henle and the collecting duct; selective reabsorption and secretion occur here, most notably to regulate reabsorption of water and sodium

477

What is the collecting duct?

a segment of the nephron that returns water form the filtrate to the bloodstream.

478

What is the juxtamedullary nephron?

accounts for 15-20% of the nephrons. long loop of henle extending into medulla, responsible for medullary osmotic gradient, important in conserving water and reabsorption

479

What is the cortical nephron?

accounts for 80-85% of nephrons; in mammals and birds, a nephron with a short loop of Henle located almost entirely in the renal cortex

480

What is the juxtaglomerular apparatus?

produces substances involved in the control of kidney function; consists of the macula densa and juxtaglomerular cells

481

What is the macula densa?

it senses NaCl and releases prostaglandin or renin

482

What are juxtaglomerular cells?

aka granular cells, these produce renin

483

What is the renal sinus?

space within kidney that is adjacent to renal medulla, contains calyces and renal pelvis

484

What are segmental arteries?

branches of renal artery after it passes through the hilum

485

What are interlobar arteries?

segmental arteries further divide into these arteries which supply blood to the arcuate arteries

486

What are arcuate arteries?

small vessels found at the base of the renal pyramids; appear as echogenic structures

487

What are interlobular arteries?

branches off of the arcuate arteries which ascend into the cortex, giving off afferent arterioles

488

What are afferent arterioles?

the small blood vessels approaching the glomerulus (proximal part of the nephron); split from interlobular arteries

489

What are glomerular capillary beds?

branch from afferent arterioles and form a network

490

What are efferent arterioles?

the small blood vessels exiting the glomerulus. at this point blood has completed its filtration in the glomerulus.

491

What do efferent arterioles give rise to?

2 capillary beds: peritubular capillaries and the vasa recta

492

What is responsible for reasorption in the loop of henle and where does it come from?

the vasa recta -- branches from the efferent arteriole

493

What is responsible for reabsorption in the distal convoluted tubule and where does it come from/

the peritubular capillaries, branch from the efferent arteriole

494

What are interlobular veins?

reuniting of the vasa recta and drain into arcuate veins

495

What are arcuate veins?

receive blood that drains from the interlobular veins and feeds into the interlobar veins

496

What are the interlobar veins?

receive blood that drains from the arcuate veins before feeding into the renal veins

497

What are renal veins?

removes deoxygenated blood from the kidneys

498

What 3 exchange processes occur within the renal nephrons?

glomerular filtration, reabsorption and secretion

499

What is glomerular filtration?

from the glomerulus to bowmans capsule

500

What is reabsorption?

from the tubules to the peritubular capillaries (tubules back into the plasma)

501

What is secretion?

from peritubular capillaries to tubules (same transport mechanism and barriers as for reabsorption)

502

What is excretion?

from the tubules out of the body

503

Where does the bulk flow of plasma occur?

from glomerular capillaries to renal bowmans capsule

504

What do starling forces do?

they drive filtration at the renal corpuscle

505

How much glomerular filtration occurs? (blood filtered)

125mL/min or 180L/day

506

What 3 barriers must. the glomerular filtrate cross to enter the bowman's capsule?

- capillary endothelial cell layer
- epithelial cell layer
- barement membrane

507

What does the basement membrane do?

it prevents filtration of proteins in glomerular capillaries

508

What 4 starling forces play roles in glomerular filtration?

glomerular capillary hydrostatic pressure (Pgc), Bowmans capsule oncotic pressure (Pibc), bowmans capsule hydrostatic pressure (Pbc) and glomerular oncotic pressure (Pigc)

509

What is the glomerular filtration pressure?

the sum of starling forces in the renal corpuscle

510

What is the glomerular capillary hydrostatic presssure (Pgc)?

high due to resistance of efferent arteriole (60mmHg) and favours filtration

511

What is the bowmans capsule oncotic pressure (Pibc)?

low due to lack of protein in filtrate (0mmHg), favours filtration

512

What is bowmans capsule hydrostatic pressure (Pbc)?

relatively high due to large volume of filtrate inclosed space (15mmHg), opposes filtration

513

What is the glomerular oncotic pressure (Pigc)?

higher than in systemic capillaries due to plasma proteins in smaller volume of plasma (29mmHg), opposes filtration

514

What are the net pressures favouring and opposing filtration at the renal corpuscle?

favouring: 60mmHg
opposing: 44mmHg
Total = 16mmHg

515

What is the rate of renal plasma flow?

625mL/min

516

What is the filtration fraction?

the fraction of blood plasma in the afferent arterioles of the kidneys that comes glomerular filtrate (20%)

517

What is the proximal tubule?

the primary location in which reabsorption, unregulatd movement of solute and water from tubules into peritubular capillaries takes place

518

Is reabsorption regulated or unregulated?

unregulated

519

Where does reabsorption often occur?

in the proximal convoluted tubule (little bit in distal convoluted tubule)

520

What are the 2 barriers for reabsorption?

epithelial cells of renal tubules an endothelial cells of capillaries

521

Which way does the apical membrane face?

faces the lumen

522

Which way does the basolateral membrane face?

faces the interstitial fluid and is indirectly in contact with the blood

523

As X and Y get reabsorbed, what occurs>

they increase the osmolarity of the plasma

524

To be passively reabsorbed by diffusion, what must a substance be able to permeate?

the plasma membrane of the capillary and tubule endothelium

525

Which 5 things are actively transported?

K, H, choline, creatinine and penicilin

526

What do intercalated cells do?

regulate absoprtion of acids from nephrons

527

What do principle cells do?

regulate the reabsorption of water

528

What does the proximal convoluted tubule (PCT) do?

consists of simple cuboidal epithelial cells with prominent brush borders of microvilli; enables mass unregulated absorption

529

What 2 sections of the loop of henle consist of simple squamous epithelial cells

descending and thin ascending

530

Which section of the loop of henle consists of simple cuboidal to low columnar epithelial cells?

the thick ascending limb

531

Which section consists of simple cuboidal epithelial cells with small invaginations?

the distal convoluted tubule

532

What is the location of nonregulated reabsorption?

the proximal tubule (70% water and sodium and 100% glucose reabsorption)

533

What is the location of regulated reabsorption and secretion?

the collecting duct and distal tubule

534

What is the location of water conservation?

the loop of henle

535

What is the mass reabsorber?

proximal tubule -- brush border provides a larger SA

536

Water reabsorption is regulated by what?

ADH

537

What does paracellular transport mean?

through junctions between adjacent cells

538

What do leaky tight junctions do?

they enable paracellular transport in proximal tubules

539

What barrier is transport regulated in the distal tubule and collecting duct?

the epithelium

540

What do tight junctions do?

limit paracellular transport in the distal tubule and collecting duct

541

What 3 factors that the amount excreted depends on?

filtered load, reabsorption rate, secretion rate

542

What is the amount of substance excreted = to?

amount filtered + amount secreted - amount reabsorbed

543

Whats another term for urination?

micturition

544

Where does urine get formed?

in the renal tubules

545

What collects urine and passes it to the ureter?

the renal pelvis

546

What is the ureter?

the tube that carries urine from the kidney to the urinary bladder

547

What does the bladder do?

stores urine until excretion

548

What does detrusor muscle do?

compresses the urinary bladder and expels urine through the urethra; powered via parasympathetic innervation (parasympathetic innervation causes contration, VV)

549

What is the internal urethral sphincter?

a circular muscle innervated by the sympathetic neurons that prevents leakage

550

What holds urine in the bladder?

voluntary skeletal muscle in the external urethral sphincter

551

What is the opening of the urethra to the outside called

the external urethral orifice

552

What is the pelvic floor?

a muscular base of the abdomen attached to the pelvis

553

What is micturition reflex?

relaxation of the urethral sphincter in response to increased pressure in the bladder