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A&P II IPAP 3-17 > Circulatory > Flashcards

Circulatory Flashcards

1
Q

Name the types of Blood Vessels.

A
  • Arteries
  • Arterioles
  • Capillaries
  • Venules
  • Veins
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2
Q

Common Structure of Arteries & Veins: 3 vessel Wall layers (External to Internal)

A
  • Tunica Externa (Adventitia)
  • Tunica Media
  • Tunica Interna (Intima)
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3
Q

What is the Tunica Externa (Adventitia) composed of?

A

Elastic and Collagen Fibers (Connective Tissue)

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4
Q

What is contained within the Tunica Externa (Adventitia)

A
  • Nerves of the vessels

- Vasa Vasorum

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5
Q

What is the Vasa Vasorum (found in the Tunica Externa)?

A

Small vessels that transport O2 and nutrients to cells of blood vessel walls

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6
Q

This layer of the vessel helps anchor it to the surrounding tissue.

A

Tunica Externa (Adventitia)

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7
Q

This layer within the Tunica Media is only found in Arteries.

A

External Elastic Lamina

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8
Q

What purpose does the External Elastic Lamina serve?

A
  • Separates the tunica media from tunica externa
  • Thin sheet of elastic fibers
  • Variable number of window-like openings (facilitate diffusion of materials through tunica externa to tunica media)
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9
Q

This layer within the Tunica Media is found in Arteries and veins.

A

Smooth Muscle (some elastic fibers) Layer

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10
Q

What purpose and functions does the Smooth Muscle Layer of the Tunica Media have (Blood Vessels)?

A
  • Regulates diameter of vessel lumen
  • Innervated by sympathetic nerve fibers
  • Contracts and relaxes for blood flow regulation as needed. (Vasoconstriction and Vasodilation)
  • Contracts vessel when damaged to limit blood loss
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11
Q

This layer of the blood vessel has direct contact with blood as it flows through the lumen.

A

Tunica Interna (Intima)

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12
Q

What are the layers of the Tunica Interna (Intima)?

A
  • Internal Elastic Lamina Layer (Arterial)
  • Basement Membrane Layer (Arterial, Venous)
  • Endothelial Cell Layer (Arterial, Venous)
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13
Q

This layer of the Tunica Interna is only found in arteries and not veins?

A

Internal Elastic Lamina Layer

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14
Q

Give the characteristics of the Internal Elastic Lamina Layer?

A
  • Separates tunica interna from tunica media
  • Thin sheet of elastic fibers
  • Variable number of window-like openings (Facilitate diffusion through tunica interna to tunica media
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15
Q

The Basement Membrane of the Tunica Interna (Intima) is also called?

A

Subendothelial Layer

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16
Q

Give the characteristics of the Basement Membrane.

A
  • Provides physical support for epithelia layer
  • Network of collagen fibers
  • Anchors endothelium to underlying connective tissue
  • Helps regulate molecular movement
  • Guides cell movement during tissue repair of blood vessels.
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17
Q

What is the purpose of the collagen fibers in the Basement Membrane of the Tunica Interna serve?

A
  • Provides significant tensile strength

- Allows for some stretching and recoil

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18
Q

What is the inner most layer of the Tunica Interna (Intima)?

A

Endothelium

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19
Q

Name the characteristics of the Endothelium of the Tunica Interna.

A
  • Lining of the lumen of the vessel
  • Continuous with endocardial lining of the heart
  • Reduces blood cell damage (smooth)
  • Reduce Friction of blood flow (Increased efficiency)
  • Secretes chemical mediators that influence contractile smooth muscle in tunica media
  • Assists with capillary permeability
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20
Q

Name the layers and sublayers of each for arterial vessels. External to Internal

A 
Tunica Externa (Adventitia)
        -1 layer- elastic and collagen fibers
Tunica Media
        -External Elastic Lamina
        -Smooth Muscle Layer
Tunica Interna
        -Internal elastic lamina layer
        -Basement Membrane Layer
        -Endothelial Cell Layer
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21
Q

Name the layers and the sublayers of each for venous vessels.

A

Tunica Externa (Adventitia)
-1 layer- elastic and collagen fibers
Tunica Media
-Smooth muscle and elastic fibers
Tunica Intima (Interna)
-Basement Membrane Layer
-Endothelial Cell Layer

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22
Q

Characteristics of Arteries?

A
  • Transport blood from the heart to the tissues of the body
  • Thicker Tunica Media layer than veins
  • Elastic fibers lending to high compliance (Walls stretch and expand easily in response to pressure increases/decreases)
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23
Q

What are the two major types of arteries?

A

Elastic

Muscular

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24
Q

What type of artery has the largest diameter lumen?

A

Elastic arteries

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25
Q

Name the elastic arteries.

A

Aorta, Pulmonary Trunk, Brachiocephalic, Subclavian, Common Carotids, Common Iliac

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26
Q

How thick is the vessel wall on an elastic artery?

A

Thin (1/10th total diameter)

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27
Q

What is within the Tunica Externa (Adventitia) of Elastic Arteries?

A

Fibroblasts, Nerve Fibers, and Vasa Vasorum (Blood Vessel Network)

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28
Q

What differences are found in the Tunica Media Layer of Elastic Arteries when compared to other arteries?

A
  • More Elastic Lamellae (elastic Fibers)
  • More collagen fibers
  • Minimal Smooth muscle
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29
Q

What differences are found in the Tunica Intima Layer of Elastic Arteries?

A

Endothelial and Myointimal Cells with supporting layer of elastin rich collagen

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30
Q

Elastic Arteries are the first place this develops.

A

Atherosclerosis

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31
Q

What purpose do Elastic Arteries serve?

A
  • Propel blood onward while ventricles are in diastole (Walls expand accounting for surge of blood in the Aorta)
    • Elastic fibers recoil and convert stred (potential) energy into kinetic energy propelling blood forward)
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32
Q

Expansion of Elastic Arteries creates a momentary storage of mechanical energy called?

A

Pressure Reservoir

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33
Q

Elastic Arteries are also know as?

A

Conducting Arteries (Conduct blood from the heart to medium sized muscular arteries

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34
Q

Give some examples of Muscular arteries?

A

Brachial, Femoral, Axillary

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35
Q

Muscular arteries are also known as?

A

Distributing Arteries

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36
Q

Size range for muscular arteries?

A

Pencil size (Femoral, Axillaries) to 0.5mm diameter

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37
Q

What difference is found in the Tunica Externa layer of muscular arteries when compared to elastic arteries?

A

Tunica Externa is thicker

-Contains fibroblasts, nerve fibers, some collagen and elastin

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38
Q

What differences are found in the Tunica Media Layer of Muscular Arteries?

A
  • Contains much more smooth muscle and less elastic fibers
  • Artery is capable of greater vasoconstriction and vasodilation
  • Helps adjust rate of blood flow
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39
Q

The Tunica Intima consist of what in Muscular Arteries?

A

Basal Lamina and Endothelial Cells

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40
Q

Muscular Arteries have a reduced ability to what? Do to the reduced amount of elastic fibers

A

Propel Blood

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41
Q

What layer of Muscular arteries perform the majority of work?

A

Tunica Media- large amount of smooth muscle (maintains a state of partial contraction)

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42
Q

The state of partial contraction is called?

A

Vascular/Vasomotor Tone (Stiffens vessel walls and helps maintain vessel pressure and efficient blood flow)

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43
Q

Define: Anastomoses

A

Union of branches of two or more arteries supplying blood to the same region of body

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44
Q

What is the alternate route an anastomoses creates called?

A

Collateral Circulation

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45
Q

Where else might Anastomoses occur?

A

Veins, Arterioles, and venules

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46
Q

What are arteries that do not anastomose called?

A

End-Arteries

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47
Q

Obstruction of end arteries cause interruption of blood supply to tissue/organs and cause damage called?

A

End-Organ/Artery Damage

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48
Q

Give the characteristics of Arterioles.

A
  • Microscopic
    • Approx 400 million
  • Diameters 15micron to 300micron
  • Very rich in smooth muscle
  • Wall thickness 1/2 of total vessel diameter
    • 7.5micron to 150micron
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49
Q

In Arterioles the Tunica Externa consist of?

A
  • Areolar Connective Tissue containing abundant unmyelinated sympathetic nerves
  • Local chemical mediators
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50
Q

The unmyelinated sympathetic nerves and chemical mediators found in the Tunica Externa of Arterioles is responsible for what?

A

Altering the diameter of the arterioles. This will vary the blood rate and resistance through these vessels

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51
Q

Arteriole Tunica Media Layer characteristics.

A

Thin- 1-2 layers of muscle cells

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52
Q

Tunica Intima of Arterioles is?

A

Thin

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53
Q

Arterioles are also known as?

A

Resistance Vessels

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54
Q

Which vessels play a key role in resistance?

A

Arterioles

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55
Q

What causes the resistance within Arterioles?

A

Vasoconstriction (smaller diameter lumen) increases blood rubbing against vessel wall causing an increase of friction (greater resistance)

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56
Q

Arterioles regulate blood flow to what part of the Circulatory system?

A

Systemic Capillary beds and thus what comes out of capillary system

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57
Q

A high rate of firing from the sympathetic nerve fibers in arteries will cause?

A

Vasoconstriction

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58
Q

A low rate of firing from the sympathetic nerve fibers in arteries will cause?

A

Vasodilation

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59
Q

What “keeps pressure in the system”, by helping to stretch the walls of arteries during heart contractions?

A

The back pressure created by constricting arterioles

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60
Q

Vasoconstriction and Vasodilation of arterioles plays what role in regards to blood pressure?

A

Vasoconstriction- Increased BP

Vasodilation- Decreased BP

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61
Q

What connects arterioles to the capillary network?

A

Metarterioles

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62
Q

What are the characteristics of Metarterioles?

A
  • Do not have a true tunica Media (Metarteriole-Capillary junction, single smooth muscle cell forms a ring)
  • Encircling smooth muscle acts as pre-capillary sphincter
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63
Q

What is the Metarteriole-Capillary Junctions (Precapillary Sphincter) role in blood flow?

A

Regulates blood flow into capillaries that branch from Metarteriole and in response to stimuli contracts reducing the size of the lumen or closes it completely

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64
Q

What are the smallest blood vessels found in the body?

A

Capillaries

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65
Q

What diameter will capillaries have?

A

5-10 microns

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66
Q

The size of a capillary will force blood cells to do what?

A
  • Blood cells are often 8microns, may fold over and pass “single file” through capillaries
  • Allows time for nutrient exchange
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67
Q

How extensive is the capillary network within the body?

A
  • Approx.. 20 billion

- Forms enormous surface area to make contact with cells of the body

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68
Q

Capillaries are the union between?

A

Arterial and Venous Blood

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69
Q

What do Capillaries consist of?

A

Single endothelial cell layer and basement membrane

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70
Q

This single endothelial cell layer and basement membrane in capillaries allows for what?

A

Nutrient, gas, and waste diffusion to and from tissue interstitial fluid/tissue cells

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71
Q

Capillaries lack what components typically found within blood vessels?

A

Tunica Media and Tunica Externa

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72
Q

What is Microcirculation?

A

Flow of blood from Metarteriole through capillaries and into postcapillary venules

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73
Q

Capillaries are also know as?

A

Exchange Vessels

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74
Q

These are found near almost every cell in the body?

A

Capillaries

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75
Q

What is significant about Muscles, The Brain, Liver, Kidneys, Nervous System in regards to capillaries?

A

The higher metabolic demand increase the capillary network

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76
Q

Where are capillaries absent?

A

Avascular Substances

  - Cornea
  - Lens of eye
  - Cartilage
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77
Q

Define: Capillary Beds

A

Network of 10-100 capillaries that arise from a single metarteriole

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78
Q

What occurs in the Capillary Bed when tissues are at rest and when tissues are active?

A
  • At Rest- small portion of capillary network receives blood because need for metabolic exchange is low
  • Active- whole capillary bed opens in order to increase efficiency of metabolic exchange
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79
Q

What is Vasomotion?

A

Contraction and relaxation of pre-capillary sphincters

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80
Q

Contraction and relaxation of pre-capillary sphincters (Vasomotion) occurs how many times a minute?

A

5-10 times per minute

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81
Q

What importance does Vasomotion serve for the capillary beds?

A
  • Regulates blood flow through capillary beds insuring all capillary beds receive blood flow during rest
  • prevents tissue from becoming ischemic without vasomotion
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82
Q

Vasomotion is mostly due to release of what from where?

A

Chemicals released by endothelial cells such as nitric oxide

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83
Q

Metabolic Theory of Auto-regulation refers to?

A

Metarteriole Sphincters constrict to all capillaries except one creating a Thoroughfare Channel directly from arteriole to venule, bypassing majority of capillary bed.

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84
Q

Thoroughfare Channel of arterioles to venules due to metarteriole sphincter constriction may occur due to?

A
  • Hemorrhage

- Increase Stroke Volume (Exercise)

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85
Q

Name the types of Capillaries.

A
  • Continuous
  • Fenestrated
  • Sinusoids
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86
Q

Most capillaries are of which type?

A

Continuous

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87
Q

Characteristics of continuous capillary.

A

Plasma membranes of endothelial cells form continuous tube interrupted only by intercellular clefts (gaps between neighboring endothelial cells)

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88
Q

Continuous capillaries are found where in the body?

A

CNS, Lungs, Skin, Muscle Tissue

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89
Q

Characteristics of Fenestrated Capillaries.

A

Plasma membranes have many fenestrations allowing for easier diffusion

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90
Q

Fenestrated Capillaries are found where in the body?

A

Kidneys, Villi of Small Intestine, Choroid Plexuses of Ventricles of Brain, Ciliary Processes of the eyes, most Endocrine Glands

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91
Q

Characteristics of Sinusoids Capillaries.

A
  • Wider and more winding than others
  • Incomplete or absent basement membranes
  • May have unusually large fenestrations
  • Very Large intercellular clefts allowing some proteins and even blood cells to pass from tissue into blood
  • Specialized lining cells adapted to function of the tissue
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92
Q

Give an example of Sinusoids Capillaries that allow blood cells to pass from tissue into blood.

A

New formed blood cells pass from bone marrow into blood stream

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93
Q

Give an example of Sinusoids Capillary that contain specialized lining cells.

A

Liver Sinusoids capillary contain phagocytes cells that remove bacteria and other debris

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94
Q

Sinusoids Capillaries can be found where in the body?

A

Spleen, Anterior Pituitary, Parathyroid, Bone Marrow, Adrenal Glands

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95
Q

When blood passes from one capillary network to another capillary network this is called?

A

Portal System

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96
Q

Give examples of where Portal Systems exist in the body?

A
  • Hepatic Portal Circulation (liver)

- Hypophyseal Portal System (Pituitary)

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97
Q

What purpose does the Portal System serve?

A
  • Transports products of one region into another in high concentrations
  • Bypasses the heart and therefore systemic circulation
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98
Q

Give an example of the Portal System.

A

Hepatic Portal System- allows liver to filter blood from the stomach, spleen, pancreas, gallbladder, and the mesenteric systems without sending that to the rest of the body

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99
Q

What are Venules?

A

Small veins that receive blood flow directly from capillary beds. (Post-capillary Venules)

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100
Q

What size are venules?

A

10-50 microns

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101
Q

What characteristics do the walls of the venules have?

A
  • Smallest venules are very porous allowing phagocytic WBCs to pass through to inflamed or infected tissue
  • Significant sites of exchange of nutrients and waste (last site of metabolic exchange)
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102
Q

At what site of the circulatory system does the immune response with WBC’s occur?

A

Venules

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103
Q

Post Capillary the venules transition into?

A

Muscular Venules

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104
Q

What differences are seen in Muscular Venules compared to Post-capillary venules?

A
  • Gain 1-2 layers of smooth muscle
  • 50-200 micron thickness
  • no metabolic exchange
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105
Q

What element/s of the vascular system is most distensible?

A

Postcapillary and Muscular Venules

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106
Q

These serve as reservoirs for large amounts of blood if needed?

A

Postcapillary and Muscular Venules

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107
Q

Blood volume increase have been measured in postcapillary and muscular venules up to what amount?

A

360%

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108
Q

What is the average thickness of venous walls?

A

1/10th of vessel diameter

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109
Q

Venous wall diameter will range from?

A

5 micron (small venules) to 30mm (Venae Cavae)

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110
Q

Tunica Externa of the venous system consists of?

A

Thickest Layer, Collagen and elastic fibers

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111
Q

Tunica Media of the venous system difference when compared to arteries?

A

Much thinner, much less smooth muscle and elastic fibers

112
Q

Tunica Interna (Intima) of venous system when compared to arteries?

A

Much thinner

113
Q

What sublayers are lacking within veins?

A
  • Internal Elastic Laminae of the Tunica Intima

- External Elastic Laminae of the Tunica Media

114
Q

The lumen of veins tend to be what compared to arteries?

A

Larger

115
Q

Many veins contain what? This is especially true in limbs.

A

Valves

116
Q

Characteristics of Valves found in veins?

A
  • Tunica Interna form cusps
  • Cusps project into the lumen with “cups” towards the heart
  • Valves prevent backflow of blood
117
Q

What is the Vascular Sinus?

A
  • Thin endothelial wall, no smooth muscle

- Surrounding dense connective tissue replaces Tunica Media and Tunica Externa in providing support.

118
Q

Give examples of where a Vascular Sinus is found?

A

Dural Venous Sinuses and Coronary Sinus

119
Q

What are Anastomotic Veins?

A
  • Veins are paired and accompany medium-to-small sized muscular arteries
  • Paired veins escort arteries and connect with one another (veins) via these anastomotic veins
120
Q

Where are Anastomotic Veins found?

A
  • Greatest number in limbs

- Superior Anastomotic Vein (Large one in Brain)

121
Q

These veins are located within the subcutaneous layer of the skin and are unaccompanied (no arteries).

A

Superficial Veins

122
Q

These travel between skeletal muscles and have small connections to superficial veins.

A

Deep Veins

123
Q

Describe Superficial Veins of the Upper Limbs.

A
  • Larger than deep veins

- Serve as pathways from capillaries of upper limb back to heart

124
Q

Describe Deep veins of Lower Limbs.

A
  • Larger than Superficial veins
  • Principle return pathway to heart
  • One-way valves in small anastomosing vessels allow blood to pass from superficial to deep veins, prevent reverse flow
125
Q

A leaky venous valve can cause veins to become dilated and twisted causing?

A

Varicose

126
Q

Varicose are most common in?

A
  • Esophagus
  • Anal Canal
  • Superficial veins of lower limbs
127
Q

What are some of the cause of Varicose?

A

Congenital issues or mechanical stress (prolonged standing/pregnancy) or aging

128
Q

Treatment for Varicose Veins?

A
  • Elastic Stocking
  • Sclerotherapy
  • Laser Occlusion
  • Stripping
129
Q

What is the blood distribution within the body at rest?

A 
64% systemic veins and venules
13% systemic arteries and arterioles
9% pulmonary blood vessels
7% systemic capillaries
7% in the heart
130
Q

What are considered the Blood Reservoirs of the body?

A

Systemic Veins and Venules

131
Q

What is the mission of the cardiovascular system?

A

Keep blood flowing through capillaries to allow for capillary exchange

132
Q

What percentage of blood is continually exchanging materials with interstitial fluid?

A

7%

133
Q

What are the three basic mechanisms that allow for exchange of substances in capillaries?

A
  • Diffusion
  • Transcytosis
  • Bulk Flow
134
Q

Which of the three basic mechanisms of exchange is most important?

A

Diffusion

135
Q

What is Diffusion?

A

Movement down the concentration gradient

136
Q

Name some of the substances that diffuse?

A
  • O2
  • CO2
  • Glucose
  • Amino Acids
  • Hormones
137
Q

Which way will O2 and nutrients move in the concentration gradient?

A

O2 and nutrients typically have higher concentration in blood and will move across (down concentration gradient) capillary bed into tissue/interstitial fluid

138
Q

Which way will CO2 and waste move in the concentration gradient?

A

CO2 and waste typically have higher concentration in tissue/interstitial fluid and will move across (down concentration gradient) capillary bed into vessels

139
Q

What substances diffuse through intercellular clefts/fenestrations?

A
  • Glucose

- Amino Acids

140
Q

What substances diffuse through Endothelial cell lipid bilayer?

A
  • Lipid soluble substances

- O2,CO2, Steroid Hormones

141
Q

Define Blood Pressure.

A

Hydrostatic pressure exerted by blood on the walls of a blood vessel

142
Q

Blood Pressure is determined by what?

A
  • Cardiac Output
  • Blood Volume
  • Vascular Resistance
143
Q

Define Mean Arterial Pressure (MAP).

A

Average blood pressure in arteries

144
Q

What is the formula used to calculate Mean ArteriaI Pressure?

A

MAP= diastolic BP+ 1/3 (systolic BP - diastolic BP)

145
Q

What is the normal range of MAP?

A

70-100 mmHg

146
Q

This is considered to be a more accurate measure of perfusion pressure.

A

Mean Atrial Pressure (MAP)

147
Q

Control of Blood Pressure by several negative feed back systems is accomplished by making adjustments in…

A
  • Heart Rate
  • Stroke Volume
  • Systemic Vascular Resistance
  • Blood Volume
148
Q

Most RBC’s and Plasma proteins can only pass through this type of capillary?

A

Sinusoids

149
Q

What type of capillary is found in most areas of the brain?

A

Continuous Capillaries

150
Q

Continuous Capillaries in the Brain are surrounded by what? And this creates what within the Brain?

A

Astrocyte Processes and creates the Blood Brain Barrier

151
Q

Due to the “tight” junctions of the BBB few substances are able to diffuse. What other way are substances able to cross the BBB and give some examples of substances?

A

Carrier Mediated

 - Glucose
 - Amino Acids
152
Q

What areas of the Brain lack the Blood Brain Barrier?

A

Hypothalamus, Pineal Gland, Pituitary Gland

153
Q

Describe the process of Transcytosis in capillaries.

A

Substances in blood plasma become enclosed in tiny pinocytic vesicles and cross via Endocytosis and Exocytosis

154
Q

Transcytosis allows what kind of material to cross the capillary walls?

A

Large, lipid-insoluble molecules
-Insulin (enters blood stream)
-Certain Antibodies (Proteins) pass from maternal
circulation into fetal circulation

155
Q

What is the passive process by which large number of ions, molecules, or particles in a fluid move together in the same direction?

A

Bulk Flow

156
Q

Bulk Flow rate of movement is _________ when compared to diffusion.

A

Much Greater

157
Q

Bulk Flow can occur as long as what exists?

A

Pressure difference- Movement from high pressure to low pressure

158
Q

Diffusion is more important for solute exchange, where as Bulk Flow is more important for?

A

Regulation of relative volumes of blood and interstitial fluid

159
Q

What is the pressure driven Bulk Flow movement of fluid and solutes from blood capillaries into interstitial fluid

A

Filtration

160
Q

What two pressures promote filtration?

A
  • Blood Hydrostatic Pressure (BHP)

- Interstitial Fluid Osmotic Pressure (IFOP)

161
Q

What is Blood Hydrostatic Pressure (BHP)?

A

Pressure blood exerts against blood vessel walls(generated by pumping action of the heart)

162
Q

What is the pressure driven Bulk Flow movement of fluids and solutes from interstitial fluid into blood?

A

Reabsorption

163
Q

What one main pressure promotes reabsorption?

A

Blood Colloid Osmotic Pressure (BCOP)

164
Q

Describe Net Filtration Pressure (NFP).

A
  • Balance of the filtration and reabsorption pressures

- Determines whether volumes of blood and interstitial fluid remain steady or change

165
Q

What is Starling’s law of the Capillaries?

A

Volume of fluid and solutes reabsorbed is near the volume of fluid filtered

166
Q

What is the equation used to calculate “Net Filtration Pressure”?

A

NFP= (BHP + IFOP) - (BCOP + IFHP)

167
Q

In the NFP equation what portion accounts for pressures that promote filtration?

A

(BHP + IFOP)
BHP= Blood Hydrostatic Pressure
IFOP= Interstitial Fluid Osmotic Pressure

168
Q

In the NFP equation what portion accounts for pressures that promote reabsorption?

A

(BCOP + IFHP)
BCOP= Blood Colloid Osmotic Pressure
IFHP= Interstitial Fluid Hydrostatic Pressure

169
Q

What is the typical mmHg at the arterial and venous end of the capillary for BHP?

A

35mmHg- Arterial end of capillary

16mmHg- Venous end of capillary

170
Q

What effect does BHP have on fluid in the capillary?

A

“Pushes” fluid out of the capillaries into interstitial space

171
Q

What effect does IFOP have on fluid in the capillary?

A

“Pulls” fluid out of capillaries into interstitial fluid

172
Q

What is the typical IFOP? This is due to what?

A

1mmHg due to only small amounts of protein present in interstitial fluid

173
Q

This pressure is due to a force caused by colloidal suspension of proteins in plasma?

A

Blood Colloid Osmotic Pressure (BCOP)

174
Q

What is the typical BCOP?

A

26mmHg

175
Q

What effect does BCOP have on fluid in the capillary?

A

“Pull” fluid from interstitial spaces into capillaries

176
Q

This is the opposing pressure to Blood Hydrostatic Pressure (BHP)?

A

IFHP (Interstitial Fluid Hydrostatic Pressure)

177
Q

What is the typical IFHP?

A

0mmHg (Noncontributory unless pathologic)

178
Q

On the arterial end of the capillary fluid movement out of the capillary and into interstitial spaces is called?

A

Filtration

179
Q

On the Venous end of the capillary fluid movement out of interstitial fluid and into capillaries is called?

A

Reabsorption

180
Q

On average how many liters per day is filtered out of capillaries into tissue?

A

20L/day

181
Q

On average how many liters per day is reabsorbed into capillaries from tissue? =percentage of total?

A

17L/day (85%)

182
Q

The remaining 3L (15%) not reabsorbed makes its way back into the blood via what?

A

Lymphatic capillaries (Lymph drains into junction of jugular and subclavian veins in upper thorax)

183
Q

Clinical Correlation: If filtration (into Interstitial fluid) greatly exceeds reabsorption (into bloodstream), what occurs?

A

Edema

184
Q

Edema is not usually visible until what percent of rise in volume occurs?

A

30%

185
Q

Excess filtration or inadequate absorption can cause what?

A

Edema

186
Q

Hemodynamics: What two factors contribute to how cardiac output is distributed into circulatory routes?

A

Flow

Resistance

187
Q

Flow can be explained by which law?

A

Poiseuille’s Law

188
Q

Poiseuille’s Law: Flow is directly proportional..?

A
  • Longitudinal Pressure Gradient (Higher gradient=Higher Flow)
  • Radius of the tube (raised to the fourth power)- (Increased radius=Increased Flow)
189
Q

Poiseuille’s Law: Flow is inversely proportional..?

A
  • Length of the tube (Increased Length=Decrease Flow)

- Viscosity of the fluid (Increased Viscosity=Decrease in Flow)

190
Q

Define: Resistance regarding blood flow.

A

Opposition to blood flow due to friction between blood and walls of blood vessels

191
Q

A higher resistance of blood flow means what in regards to amount and speed of blood flow?

A
  • Less amount of flow

- Lower speed

192
Q

Resistance is directly proportional..?

A
  • Viscosity (Increased Viscosity=Increased Resistance)

- Length of the tube (Increased Length=Increased Resistance)

193
Q

Resistance is inversely proportional..?

A

-Radius (Increased radius=Decreased Resistance)

194
Q

What three factors does Vascular Resistance (VR) depend on?

A
  • Size of the Lumen (Radius)
  • Blood Viscosity
  • Total Blood Vessel Length
195
Q

What is Systemic Vascular Resistance (SVR)?

A

All the vascular resistance offered by systemic blood vessels

196
Q

Systemic Vascular Resistance (SVR) is also know as?

A

Total Peripheral Resistance (TPR)

197
Q

What portion of the circulatory vessels contribute most to resistance?

A

Arterioles, Capillaries, and Venules

198
Q

These need only to change their diameter slightly to have a large effect on SVR (Systemic Vascular Resistance)?

A

Arterioles

199
Q

The major function of these is to control SVR (BP)?

A

Arterioles

200
Q

Define: Syncope

A

Fainting, sudden temporary loss of consciousness that is not due to head trauma, followed by spontaneous recovery

201
Q

What causes Vasodepressor Syncope?

A

Sudden emotional stress or real threat

202
Q

What causes Situational Syncope?

A

Antihypertensive, diuretics, vasodilators

203
Q

What causes Orthostatic Syncope?

A

Excessive decrease in BP when one stands from seated position

204
Q

What affect do capillaries have on velocity and in-turn has what effect on the cross-sectional area?

A

Velocity of blood flow is slowest

-Greatest aggregate of cross-sectional area

205
Q

What affect do large vessels (aorta) have on velocity and in-turn has what effect on the cross-sectional area?

A

Velocity of blood flow is fastest

-Smallest aggregate cross-sectional area

206
Q

What has an inverse relationship to the cross sectional area?

A

Velocity (cm/sec)- Increase Cross Section=Decrease Velocity

207
Q

What is the Cross Sectional area and velocity of the Aorta?

A

3-5cm^2 (smallest cross section)

40cm/sec (fastest velocity)

208
Q

What is the Cross Sectional area and velocity of the Venae Cavae?

A

14cm^2 (Larger Cross section compared to aorta)

15cm/sec (slower velocity compared to aorta)

209
Q

What is the Cross Sectional area and velocity of Capillaries?

A

4500-6000cm^2 (Largest Cross section compared to aorta)

0.1cm/sec (slowest velocity compared to aorta

210
Q

What is meant by Laminar Flow?

A

Greatest velocity is in center of vessel

Lowest velocity is near vascular wall

211
Q

What is Streamlining?

A

Caused by shear stress produced as blood flows past stationary wall

212
Q

What is Turbulent Flow?

A

irregularities in flow pattern

213
Q

What are some of the patterns in turbulent flow?

A

Whorls
Vortices
Eddies

214
Q

What is meant by Circulation Time?

A

Time required for 1 drop of blood to pass from right atrium through pulmonary circulation, back to left atrium, through systemic circulation, down to a foot and back to right atrium.

215
Q

Typical Circulation Time in a resting healthy adult?

A

1 minute

216
Q

What is Venous Return?

A

Volume of blood flowing back to the heart through systemic veins

217
Q

Describe what is occurring in the Skeletal Pump of venous return when standing at rest?

A

Venous valves (distal and proximal) are open allowing blood to flow towards the heart

218
Q

Describe what is occurring in the Skeletal Pump when the leg muscles contract such as standing on tiptoes?

A

Blood pushes open Proximal Valve (Milking) and at the same time Distal Valve closes due to blood pushing against it from contraction of muscle

219
Q

Describe what is occurring in the Skeletal Pump when the leg muscle is then relaxed after contraction?

A

Proximal Valve closes and distal valve opens (higher pressure at distal end since it was closed)

220
Q

Describe what is occurring in the Respiratory Pump during Inhalation?

A

Diaphragm moves downward causing decreased pressure in thoracic cavity and increased pressure in abdominal cavity. Results in compression of abdominal veins pushing greater volume of blood through thoracic cavity towards the heart

221
Q

Describe what is occurring in the Respiratory Pump during Exhalation?

A

Diaphragm moves upward causing an increase in thoracic cavity pressure and decreased pressure in abdominal cavity. Results in valves closing preventing backflow from thoracic veins into abdomen

222
Q

Where is the Cardiovascular (CV) Center located?

A

Medulla Oblongata

223
Q

What role does the Cardiovascular Center play in control of Blood Pressure and Flow?

A
  • Helps regulate heart rate and stroke volume

- Controls neural, hormonal, and local negative feedback systems (help regulate BP)

224
Q

What does the CV center regulate?

A
  • Heart Rate
  • Contractility
  • Blood Vessel Diameter
225
Q

These are not clearly separated anatomically but they communicate with each other and function together to make up the CV center in it entirety?

A
  • Cardiostimulatory Center
  • Cardioinhibitory Center
  • Vasomotor Center
226
Q

The Cardiostimulatory Center has?

A

Neurons that stimulate the heart

227
Q

The Cardioinhibitory Center has?

A

Neurons that inhibit the heart

228
Q

The Vasomotor Center is made up of and each has?

A
  • Vasoconstrictor Center- Neurons that cause constriction of vessels
  • Vasodilator Center- Neurons that cause dilation of vessels
229
Q

What provides input to the CV Center?

A
  • Cerebral Cortex, Limbic System, Hypothalamus

- Sensory Receptors (Proprioceptors, Baroreceptors, Chemoreceptors)

230
Q

What function do Proprioceptors serve?

A

Monitor movement of joints and muscles, accounts for rapid rise in heart rate at beginning of exercise

231
Q

What function do Baroreceptors serve?

A

Monitor Changes in pressure and stretch in vessel walls

232
Q

What function do Chemoreceptors serve?

A

Monitor the concentration of various chemical in blood

233
Q

Output from CV Center travels along?

A

Sympathetic and Parasympathetic Neurons of the Autonomic Nervous System (ANS)
Vasomotor Nerves

234
Q

How do Sympathetic Impulses reach the heart?

A

Cardiac Accelerator Nerves (Thoracic Vertebrae)

235
Q

Cardiac Accelerator Nerves will have what effect on the heart?

A

Increased Heart Rate and Contractility

236
Q

Parasympathetic Impulses travel along what nerve?

A

Vagus Nerve

237
Q

Vagus Nerve has what effect on the heart?

A

Decrease in Heart Rate

238
Q

Output from CV Center through Vasomotor nerves sends impulses to what?

A

Smooth muscle in blood vessel walls

239
Q

What is the Moderate State of Tonic Contraction

A

Vasomotor/Vascular Tone

240
Q

This sets the resting level of vascular resistance?

A

Vasomotor/Vascular Tone

241
Q

These two types of reflexes allow the nervous system to regulate blood pressure (Negative Feedback Loop)?

A
  • Baroreceptor Reflexes

- Chemoreceptor Reflexes

242
Q

What is the function of Baroreceptors and Chemoreceptors?

A

Sense blood pressure and chemical composition of blood for feedback to the circulatory and endocrine system

243
Q

What are Baroreceptors?

A

Pressure-sensitive sensory receptors

244
Q

What are the locations and function of Baroreceptors?

A

Aorta, Internal Carotid Arteries, other large arteries in neck and chest. Function: Send impulses to CV center to help regulate BP

245
Q

What are the two most important Baroreceptor Reflexes?

A

Carotid Sinus Reflex

Aortic Reflex

246
Q

Carotid Sinus Reflex Function?

A

Helps regulate BP in the Brain

247
Q

What is the location of the Carotid Sinus?

A

Small Widening of right and left internal carotid arteries just superior to where they branch from common carotid arteries

248
Q

What occurs when BP stretches the wall of Carotid Sinus?

A

Baroreceptor is stimulated, nerve impulses propagate from sinus baroreceptors over sensory axons of carotid sinus branch of glossopharyngeal nerves (CN IX) then into the CV Center

249
Q

The Aortic Reflex is initiated by?

A

Baroreceptors in the Ascending Aorta and Arch of Aorta

250
Q

The Aortic Reflex regulates what?

A

Systemic BP

251
Q

Nerve impulses from baroreceptors in the Aortic Reflex reach the CV Center Via?

A

Sensory axons of Vagus Nerve (CN X)

252
Q

What occurs when baroreceptors are stretched less (Drop in BP)?

A
  • Nerve Impulses sent at slower rate to CV Center
  • CV Center decreases parasympathetic stimulation through Vagus Nerve and increases sympathetic stimulation through Cardiac Accelerator nerves
    - Hormones stimulated to be secreted in the body
  • Heart Beats faster and more forcefully (Cardiac output and systemic vascular resistance increase)
  • This increases BP to normal levels
253
Q

What hormones are stimulated to be secreted in the body in response to increased sympathetic stimulation

A

Epinephrine and Norepinephrine

254
Q

What occurs when baroreceptors are stretched more (Increase in BP)?

A

-Nerve impulses sent at a faster rate to CV Center
-CV Center increases parasympathetic stimulation through Vagus Nerve and decreases sympathetic stimulation through cardiac accelerator nerves
-Heart Beats flower and less forcefully (Cardiac output and systemic vascular resistance decrease)
-Slows rate of impulses to vasomotor neurons that
cause vasoconstriction, results in vasodilation
-This decreases BP to normal levels

255
Q

What are Chemoreceptor Reflexes?

A

Sensory receptors that monitor chemical composition of blood. Detect changes in blood concentration of O2, CO2, Hydrogen ions

256
Q

Chemoreceptors are located very close to what?

A

Baroreceptors

257
Q

Name the two location of Chemoreceptors?

A

Carotid Bodies- Chemoreceptors in carotid arteries

Aortic Bodies- Chemoreceptors in Aortic Arch

258
Q

What will stimulate Chemoreceptors?

A

Hypoxia- reduced plasma O2
Acidosis- increase in H+ concentration
Hypercapnia- Increase in CO2 in plasma

259
Q

What occurs when Chemoreceptors are stimulated?

A
  • Impulse is sent to CV Center
  • CV Center increases sympathetic stimulation to arterioles and veins causing vasoconstriction
  • Vasoconstriction increases BP
260
Q

What is Autoregulation (Regarding BP)?

A
  • Ability of tissue to automatically adjust blood flow to match the metabolic demands
  • Local changes occurring in capillary beds regulating vasomotion
261
Q

What occurs with an increased O2 demand?

A
  • Vasodilators dilate arterioles and relax precapillary sphincters allowing for more blood
  • Opposite occurs as well with vasoconstrictors
262
Q

Autoregulation also plays what role in blood flow in the brain?

A

Regional blood flow in the brain will change distribution to various regions for different mental and physical activities (Speaking or listening, blood is increased to the regions that control speech and auditory areas)

263
Q

What two different stimuli cause autoregulatory changes in blood flow?

A

Physical Changes

Vasodilation and Vasoconstriction Chemicals

264
Q

Physical Changes: Warming and Cooling promote what regarding Vasodilation and Vasoconstriction?

A

Warming- Vasodilation

Cooling- Vasoconstriction

265
Q

What types of cells release chemicals that indirectly alter blood-vessel diameter?

A

WBC’s, platelets, smooth muscle fibers, macrophages, endothelial cells

266
Q

Name some Vasodilating Chemicals?

A

K+, H+, Lactic Acid, Adenosine, Nitric Oxide (NO), Kinins, Histamine

267
Q

Name some Vasoconstricting Chemicals?

A

Thromboxane A2, Superoxide Radical, Serotonin, Endothelins

268
Q

Regarding Autoregulation of BP what occurs in response to low O2 in Systemic Circulation?

A

Systemic vessels dilate to allow for more oxygenated blood flow

269
Q

Regarding Autoregulation of BP what occurs in response to low O2 in Pulmonary Circulation?

A

Pulmonary vessels constrict to push blood to areas that are highly ventilated by “fresh air” to increase O2 Rapidly

270
Q

What is Pulse Pressure?

A

Difference between systolic and diastolic pressure (normally 40mmHg)

271
Q

What can cause a Narrow Pulse Pressure (<25% of systolic)

A

Blood loss; anything that reduces left ventricular function

272
Q

What can cause a Wide Pule Pressure (can be 100mmHg+)?

A
  • Exercise, not a problem as long as a return to normal occurs within 10 min of rest
  • Pathologic- stiffness of major arteries; Aortic regurg; hyperthyroidism
273
Q

What makes up Systemic Circulation?

A
  • All arteries/arterioles that carry oxygenated blood from left ventricle to systemic capillaries
  • All venules and veins that carry deoxygenated blood returning to right atrium after flowing through body organs
274
Q

Name the subdivisions of systemic circulation?

A
  • Coronary
  • Cerebral
  • Hepatic Portal
275
Q

What are considered Other Circulatory Routes?

A
  • Pulmonary Circulation

- Fetal Circulation

276
Q

What is Pulmonary Circulation?

A

Deoxygenated blood pumped from right ventricle through pulmonary arteries into lungs through pulmonary veins to left atria.

A&P II IPAP 3-17 (12 decks)

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