Circulatory system

Question 1

Into how many areas can the functions of the circulatory system be divided?

Answer 1

3.

Question 2

Which are the three areas of the functions of the circulatory system?

Answer 2

1. Transportation.
2. Regulation.
3. Protection.

Question 3

What happens to the transportation area based on the substances of cellular metabolism?

Answer 3

All of the substances essential for cellular metabolism are transported by the circulatory system.

Question 4

What is a substance essential for cellular metabolism which is transported by the circulatory system?

Answer 4

Oxygen.

Question 5

What happens at the transportation area, based on the nutrients?

Answer 5

The digestive system is responsible for the mechanical and chemical breakdown of food so that it can be absorbed through the intestinal wall into the blood and lymphatic vessels. The blood then carries these absorbed products of digestion through the liver to the cells of the body.

Question 6

What happens at the transportation phase, based on waste products?

Answer 6

Metabolic wastes , urea, excess water and ions, and other molecules not needed by the body are carried by the blood to the kidneys and excreted in the urine.

Question 7

What happens to the regulation phase in general?

Answer 7

The circulatory system contributes to both hormonal and temperature regulation.

Question 8

What happens at regulation phase, based on hormonal level?

Answer 8

The blood carries hormones from their site of origin to distant target tissues where they perform variety of regulatory functions.

Question 9

What happens to regulation phase, based on temperature?

Answer 9

Temperature regulation is aided by the diversion of blood from deeper to more superficial cutaneous vessels or vice versa. When the ambient temperature is high, diversion of blood from deep to superficial vessels helps cool the body, when the ambient temperature is low, the diversion of blood from superficial to deeper vessels helps keep the body warm.

Question 10

What happens at protection phase in general?

Answer 10

The circulatory system protects against blood loss from injury and against pathogens, including foreign microbes and toxins introduced into the body.

Question 11

What happens at protection phase, based on clotting?

Answer 11

The clotting mechanism protects against blood loss when vessels are damaged.

Question 12

What happens at protection phase, based on immune?

Answer 12

The immune function of the blood is performed by the leukocytes, white blood cells, that protect against many disease-causing agents, pathogens.

Question 13

How many layers do the large and medium veins and arteries have in common?

Answer 13

3.

Question 14

Which are the 3 layers that large and medium veins and arteries have in common?

Answer 14

Tunica externa.
Media.
Interna.

Question 15

What is the critical difference between large and medium veins and arteires?

Answer 15

The presence of the endothelium in large veins and arteries.

Question 16

Where else is an endothelial layer present?

Answer 16

In venules and arterioles.

Question 17

What is the endothelial layer?

Answer 17

The main structural component of the capillaries.

Question 18

What does the thick muscle layer of the arteries allow them to do?

Answer 18

To trans-port blood ejected from the heart under high pressure.

Question 19

What does the thinner muscle layer of veins allow them to do?

Answer 19

To fill out when an increased amount of blood enters them.

Question 20

What does the one-way valves of the veins do?

Answer 20

Ensure that blood flows back to the heart.

Question 21

What do capillaries facilitate?

Answer 21

The rapid exchange of materials between the blood and interstitial fluid.

Question 22

What do blood vessels form?

Answer 22

A tubular network throughout the body.

Question 23

What does a tubular network throughout the body permit?

Answer 23

Blood to flow from the heart to all the living cells of the body and then back to the heart.

Question 24

Where does the blood leaving the heart pass?

Answer 24

Through vessels of progressively smaller diameters.

Question 25

How are the vessels of smaller diameters called?

Answer 25

Arteries. Arterioles. Capillaries.

Question 26

What are the capillaries?

Answer 26

Microscopic vessels.

Question 27

What do the capillaries join?

Answer 27

The arterial flow to the venous flow.

Question 28

Where does the blood returning to the heart from the capillaries pass?

Answer 28

Through vessels of larger diameters.

Question 29

How are the vessels with larger diameters called?

Answer 29

Venules. | Veins.

Question 30

Of what are the walls of arteries and veins composed?

Answer 30

Of 3 coats/tunics.

Question 31

What is the outermost layer?

Answer 31

The tunica externa.

Question 32

What is the middle layer?

Answer 32

The tunica media.

Question 33

What is the inner layer?

Answer 33

The tunica interna.

Question 34

Of what is the tunica externa composed?

Answer 34

Of connective tissues.

Question 35

Of what is the tunica media composed?

Answer 35

Of smooth muscle.

Question 36

Of how many part does the tunica interna consist?

Answer 36

Of 3 parts.

Question 37

Which are the 3 parts of the tunica interna?

Answer 37

1. Endothelium. 2. A layer of glycoproteins. 3. Elastin.

Question 38

What is the endothelium?

Answer 38

An inner-most simple squamous epithelium.

Question 39

What is a layer of glycoproteins?

Answer 39

The basement membrane overlying some connective tissue fibres.

Question 40

What is elastin?

Answer 40

A layer of elastic fibres.

Question 41

What does elastin form?

Answer 41

An internal elastic lamina.

Question 42

What is the diameter of small muscular arteries?

Answer 42

100um/less.

Question 43

Why do small muscular arteries branch?

Answer 43

To form smaller arterioles.

Question 44

What is the diameter of smaller arterioles?

Answer 44

20-30um.

Question 45

What can the blood from the arterioles enter in some tissues?

Answer 45

The venules through arterio-venous anastomoses.

Question 46

What are the arterio-venous anastomoses?

Answer 46

Direct connections between small arteries and small veins.

Question 47

Into what does blood from arterioles pass in most cases?

Answer 47

Into capillaries.

Question 48

What are the capillaries?

Answer 48

The narrowest of blood vessels.

Question 49

What is the diameter of capillaries?

Answer 49

7-10um.

Question 50

Where are gases and nutrients exchanged?

Answer 50

In capillaries. | Between the blood and the tissues.

Question 51

What does the contraction of arteriolar smooth muscle cause?

Answer 51

Vasoconstriction.

Question 52

What does relaxation of arteriolar smooth muscle cause?

Answer 52

Vasodilation.

Question 53

What does the arterial system do?

Answer 53

It branches extensively.

Question 54

Why does the arterial system branch extensively?

Answer 54

To deliver blood to over 40 billion capillaries in the body.

Question 55

What is the number of capillary branches?

Answer 55

So great.

Question 56

How far away is any cell in the body from a blood capillary?

Answer 56

60-80um.

Question 57

What do the tiny capillaries provide?

Answer 57

A total surface area of 1,000 square miles.

Question 58

Why do the tiny capillaries provide a 1,000 square miles surface area?

Answer 58

For exchanges between blood and tissue fluid.

Question 59

On what does the amount of blood flowing through a particular capillary bed depend?

Answer 59

On the resistance to blood flow in the small arteries and arterioles that supply blood to that capillary bed.

Question 60

What does vasoconstriction in the small arteries and arterioles decrease?

Answer 60

Blood flow to the capillary bed.

Question 61

What does vasoconstriction of the small arteries and arterioles increase?

Answer 61

Blood flow.

Question 62

Where does high resistance occur in small arteries and arterioles?

Answer 62

In resting skeletal muscles.

Question 63

What does the high resistance in the small arteries and arterioles in resting skeletal muscles reduce?

Answer 63

The capillary blood flow to 5-10% of its maximum capacity.

Question 64

By what does the blood flow in some organs like intestine be regulated?

Answer 64

By circular muscle bands.

Question 65

How are the circular muscle bands that regulate the blood flow in some organs called?

Answer 65

Precapillary sphincters.

Question 66

Where do precapillary sphincters exist?

Answer 66

At the start of the capillaries.

Question 67

Where is the most of the total blood volume contained?

Answer 67

In the venous system.

Question 68

What do arteries provide to the blood flow from the heart?

Answer 68

Resistance.

Question 69

What can veins do as they collect additional amounts of blood?

Answer 69

They can expand.

Question 70

How much is the average pressure in the veins?

Answer 70

2 mmHg.

Question 71

How much is the average arterial pressure?

Answer 71

100 mmHg.

Question 72

How is the low venous pressure characterised?

Answer 72

Insufficient to return blood to the heart form the lower limbs.

Question 73

Where do veins pass?

Answer 73

Between skeletal muscle groups.

Question 74

What do skeletal muscle groups provide as they contract?

Answer 74

A massaging action.

Question 75

What is ensured to the heart, as the veins are squeezed by contracting skeletal muscles?

Answer 75

A one-way flow of blood.

Question 76

By what is the one-way flow of blood ensured to the heart, as the veins are squeezed by contracting skeletal muscles?

Answer 76

By the presence of venous valves.

Question 77

How is the effect of the massaging action of skeletal muscles on the venous blood flow often described?

Answer 77

As the skeletal muscle pump.

Question 78

On what does the rate of venous return to the heart depend?

Answer 78

On the action of skeletal muscle pumps.

Question 79

Across which part does the exchange occur?

Answer 79

A continuous capillary wall.

Question 80

Where do slit like gaps occur?

Answer 80

Between adjacent endothelial cells.

Question 81

What do slit like gaps between adjacent endothelial cells form?

Answer 81

Pores within the capillary wall.

Question 82

What do the pores within the capillary wall allow?

Answer 82

Fluid to escape the circulation wash the tissue cells --> form extracellular/interstitial fluid.

Question 83

As what is the composition of extracellular/interstitial fluid same?

Answer 83

A the blood plasma.

Question 84

What are some small water-soluble substances?

Answer 84

Salts. Sugars. amino acids.

Question 85

Between what are small water-soluble substances exchanged?

Answer 85

Between the plasma and the interstitial fluid.

Question 86

Through what do small water-soluble substances pass to be exchanged between the plasma and the interstitial fluid?

Answer 86

Through the water-filled pores.

Question 87

Where are lipid-soluble substances exchanged?

Answer 87

Across the capillary wall.

Question 88

By what do the lipid-soluble substances pass to be exchanged across the capillary wall?

Answer 88

Through the endothelial cells.

Question 89

By what are proteins to be moved across exchanged?

Answer 89

By vesicular transport.

Question 90

What can plasma proteins not generally do?

Answer 90

Escape from the plasma across the capillary wall.

Question 91

What does the low diffusion distance between the capillary walls and tissue cells permit?

Answer 91

Rapid diffusion of solutes down their concentration gradients.

Question 92

From where does oxygen move does its concentration gradient?

Answer 92

From the blood to the respiring cell.

Question 93

From where does CO2 move down its concentration gradient?

Answer 93

From the respiring cells to the blood.

Question 94

What is the lymphatic system?

Answer 94

A network of tissues and organs.

Question 95

What does the lymphatic system help?

Answer 95

The body of toxins, wastes and other unwanted materials.

Question 96

What is the primary function of the lymphatic system?

Answer 96

To transport lymph.

Question 97

What is lymph?

Answer 97

A fluid.

Question 98

What does lymph contain?

Answer 98

Infection-fighting white blood cells throughout the body.

Question 99

What is CV?

Answer 99

A closed system.

Question 100

What is lymphatic system?

Answer 100

An open system.

Question 101

What is one of the main functions of the lymphatic system?

Answer 101

To provide an accessory return route to the blood.

Question 102

Why does lymphatic system provide an accessory return route to the blood?

Answer 102

For interstitial fluid.

Question 103

What does interstitial fluid surround and fill out?

Answer 103

Organs.

Question 104

What is a characteristic of the lymphatic system?

Answer 104

An extensive branching throughout the body.

Question 105

For what can the lymphatic system be a primary route?

Answer 105

For certain cancers.

Question 106

What is an example of cancers where the lymphatic system can be a primary route for?

Answer 106

Breast cancer.

Question 107

Why can the lymphatic system be a primary route for cancers?

Answer 107

To spread to other parts of the body.

Question 108

What do blind-ended initial lymphatics pick up?

Answer 108

Excess fluid.

Question 109

By what is the excess fluid picked up by the blind-ended initial lymphatics filtered?

Answer 109

By blood capillaries.

Question 110

Where do the blind-ended initial lymphatics return the excess fluid once it is filtered by blood capillaries?

Answer 110

To the venous system in the chest.

Question 111

What do the overlapping edges of the endothelial cells create?

Answer 111

Valve-like openings.

Question 112

Where do the overlapping edges of the endothelial cells create valve-like opening?

Answer 112

In the vessel wall.

Question 113

Where does fluid pressure occur in the endothelial cells?

Answer 113

On the outside and the inside of the vessel.

Question 114

What does the fluid pressure on the outside of the endothelial cells push?

Answer 114

The endothelial cell's free edge inward.

Question 115

What does the fluid pressure on the outside of the endothelial cells permit?

Answer 115

Entrance of interstitial fluid = lymph.

Question 116

What does the fluid pressure on the inside of the endothelial cells force?

Answer 116

The overlapping edges together.

Question 117

Why does the fluid pressure on the inside of the endothelial cells force the overlapping edges together?

Answer 117

So that lymph cannot escape.

Question 118

What is the blood pressure in the capillaries?

Answer 118

Very low. | Close to zero.

Question 119

Why is the blood pressure in the capillaries very low?

Answer 119

A a consequence of the extensive branching.

Question 120

Where does the large increase cross sectional area in the capillaries result?

Answer 120

In a large drop in blood pressure.

Question 121

How is the flow rate through a vessels calculated?

Answer 121

Volume of blood passing through/unit of time.

Question 122

To what is the flow rate trough a vessel directly proportional?

Answer 122

To the pressure gradient.

Question 123

To what is the flow rate through a vessel inversely proportional?

Answer 123

To vascular resistance.

Question 124

What is the equation of flow rate through a vessel?

Answer 124

F=ΔP/R.

Question 125

What does the F of the flow rate through a vessel show in the F=ΔP/R equation?

Answer 125

Flow rate of blood through a vessel.

Question 126

What does the ΔP of the flow rate through a vessel show in the F=ΔP/R equation?

Answer 126

Pressure gradient.

Question 127

What does the R of the flow rate through a vessels show in the F=ΔP/R equation?

Answer 127

Resistance of blood vessels.

Question 128

What happens to the flow rate, as the difference in pressure (ΔP) between the two ends of a vessel increase?

Answer 128

It increases proportionally.

Question 129

By what is the flow rate determined?

Answer 129

By the difference in pressure between the two ends of a vessel.

Question 130

By what is the flow rate not determined?

Answer 130

By the magnitude of the pressure at each end.

Question 131

What is resistance?

Answer 131

The hindrance/obstacle = εμπόδιο to blood flow through a vessel.

Question 132

What are the factors that affect the resistance?

Answer 132

Blood viscosity. Vessel length. Vessel radius.

Question 133

What is the blood viscosity?

Answer 133

The friction/rubbing between molecules of a fluid during flow.

Question 134

What does the vessel length show?

Answer 134

The longer the vessel the greater the resistance to flow?

Question 135

What does the vessel radius show?

Answer 135

The smaller the radius the greater the resistance.

Question 136

What is the major determinant of resistance to flow?

Answer 136

The vessel radius.

Question 137

What does a small change in radius produce?

Answer 137

Significant change in blood flow.

Question 138

To what is resistance (R) proportional to?

Answer 138

1/r4.

Question 139

What does the doubling of the radius reduce?

Answer 139

The resistance to 1/16th of the original value.

Question 140

What does the doubling of the radius increase?

Answer 140

The flow to 16-fold.

Question 141

What does the smaller-radius vessel offer to blood flow?

Answer 141

More resistance.

Question 142

Why does the smaller-radius vessel offer more resistance to blood flow?

Answer 142

Because the blood makes contact with a larger surface area.

Question 143

Why does the doubling of the radius decrease the resistance to 1/16th an decrease the flow 16 times?

Answer 143

Because the resistance is inversely proportional to the fourth power of the radius.

Question 144

What is the systolic pressure?

Answer 144

The peak pressure exerted in the arteries when blood is pumped into them during ventricular systole.

Question 145

What is the diastolic pressure?

Answer 145

The lowest pressure exerted in the arteries when blood is draining off into the vessels downstream during ventricular diastole.

Question 146

What is the pulse pressure?

Answer 146

The difference between systolic and diastolic pressure.

Question 147

What is the mean pressure?

Answer 147

The average pressure throughout the cardiac cycle.

Question 148

Between what numbers does the left ventricular pressure swing during diastole and systole?

Answer 148

Between a low pressure of 0 mmHg during diastole. | To a normal high pressure of 120 mmHg during systole.

Question 149

Between what does arterial blood pressure fluctuate, each cardiac cycle?

Answer 149

Between a peak systolic pressure of 120 mmHg and a low diastolic pressure of 80 mmHg.

Question 150

What is the characteristic of arterial blood pressure?

Answer 150

It is of the same magnitude throughout the large arteries.

Question 151

What happens to the pressure due to the arterioles' high resistance?

Answer 151

It drops very steeply = απότομα.

Question 152

To what are the systolic-to-diastolic swings in pressure converted due to arterioles' high resistance, when blood flows through the arterioles?

Answer 152

To a non-pulsatile pressure.

Question 153

At what rate does the pressure continue to decline, as blood flows through the capillaries and venous system?

Answer 153

At a slower rate.

Question 154

What is the circulatory system?

Answer 154

An extensive network of vessels.

Question 155

What does the circulatory system supply?

Answer 155

Nutrients.

Question 156

What does the circulatory system remove?

Answer 156

Waste from tissues.

Question 157

For what is the maintenance of the correct pressure in the system necessary?

Answer 157

For its physiological function.

Question 158

How does the pressure change?

Answer 158

Constantly.

Question 159

How is the pressure designed?

Answer 159

To expand and relax quickly and regionally.

Question 160

What do smooth muscle, structural and elastic proteins do?

Answer 160

They combine to expand and relax quickly and regionally the pressure changes.

Question 161

What are capillaries?

Answer 161

One cell thick.

Question 162

Why are capillaries one cell thick?

Answer 162

To give minimum diffusion distance.

Question 163

What does the vessel radius determine?

Answer 163

Resistance and flow rate.

Question 164

What is the lymphatic system?

Answer 164

A specialised extension of this CV system.