Blood Vessels

Front 1

Blood Vessels form

Back 1

form a closed system composed of arteries, arterioles, capillaries, venules, and veins

Front 2

An artery and a vein

Back 2

is a vessel taking blood away from the heart and a vein is a vessel returning blood to the heart

Front 3

Walls for arteries and veins have 3 coats
what are they

Back 3

Tunica intima
Tunica media
Tunica externa or tunica adventicia

Front 4

Tunica intima

Back 4

inside lining of vessel
1. layer of simple squamous endothelium
2. layer of elastic fibers (found only in artery)

Front 5

Tunica Media

Back 5

layer of smooth muscle and elastic fibers ( veins have more connective tissue fibers mixed with the smooth muscle)

Front 6

Tunica externa or tunica adventicia

Back 6

connective tissue located on the outside

Front 7

Arteries
Characteristics

Back 7

Walls are thicker and contain more smooth muscle.
Lumen is round( particularly in smaller vessels)
Valves are absent

Front 8

Arteries
Types

Back 8

Elastic or conducting arteries
Distributing or muscular arteries

Front 9

Elastic or conducting arteries

Back 9

large vessels that contain more elastin and muscle fibers. ( Aorta and its direct branches)

Front 10

Distributing or lmuscular arteries

Back 10

distributes blood to various parts of the body and is composed of thick tunica that constricts and dilates

Front 11

Arterioles

Back 11

are small arteries that contain all three coats on the arterial end, but are composed of an endothelial ling with a few smooth muscle cells towards the capillary end.

Front 12

Capillaries
Characteristics

Back 12

.Smallest 7-10 um microns in diameter
.Walls are composed of single layer of simple squamous epithelium with basement membrane.
*Amount of blood flowing through a capillary is determined by a precapillary sphincter muscle located at the origin of the capillary.
With few expectations a capillary should be located 60-80 microns of any tissue cell.
. Capillaries contain approx. 250 ml. of blood out of the 5000 ml. of blood flowing through the vessels at any time.
.Capillaries function as the area of exchange between the blood and the body tissues.

Front 13

Types of Capillaries

Back 13

Continuous
Fenestrated
Discontinous

Front 14

Continuous

Back 14

adjacent endothelial cells closely joined. Located in muscles, lungs, adipose, and central nervous system. contain many pinocytic vesicles.

Front 15

Fenestrated

Back 15

Capillaries contain large pores covered with the basement membrane. Located int eh kidneys, endocrine glands, intestines, and choroid plexus of brain.

Front 16

Discontinuous

Back 16

larger spaces between the endothelial cells. Located int he liver, spleen, and bone marrow.

Front 17

Metarteriole

Back 17

Connects arteriole to venule

Front 18

True capillary

Back 18

Are not the direct flow route from arteriole to venule

Front 19

Venule

Back 19

Capillaries come together to make venules composed of a Tunica interna and a tunica externa.

Front 20

Veins

Back 20

Vessels that return blood to the heart

Front 21

Veins
Characteristics

Back 21

. Have less smooth muscle and more connective tissue.
. Lumen partially collapsed.
. Contain valves

Front 22

Veins
Functions

Back 22

. Return blood to heart
. Act as blood reservoirs (approx. 2/3 of blood volume located in veins not active).

Front 23

Anastomosis

Back 23

Junction between 2 vessels supplying same area. ( where vessels come together) example. circle of willis

Front 24

Collateral circualtion

Back 24

Two vessles supplying the same area and providing an alternate route for blood flow due to an anastomosis

Front 25

End arteries

Back 25

Vessels that do not anastomos (go to one area)

Front 26

Blood pressure

Back 26

Pressure blood exerts on any vessel.

Front 27

Factors That Affect Arterial Pressure

Back 27

. Cardiac output
. Blood volume
. Peripheral resistance

Front 28

Cardiac output

Back 28

decrease in stroke volume or heartbeat leads to decrease in blood pressure

Front 29

Blood volume

Back 29

directly proportinal to blood pressure. Anything that increases blood volume increase pressure
1. ADH
2. Aldosterone

Front 30

Periphral resistance

Back 30

resistance to blood flow by force of friction between blood and walls of vessles.
1. Any condition that increases viscosity increases blood pressure
2. The smaller the diameter of the vessel the more resistance
3. The longer the vessel, the more resistance. for each pound of fat, the body mkes 200 additional miles of capillaries

Front 31

Control of Blood Pressure

Back 31

Increase in heart rate and muscular contractions increases blood pressure. Factors controlling heart rate and force on contraction also affect blood pressure

Front 32

Factors acting on blood vessels

Back 32

. Vasomotor center in medulla controls diameter of blood vessels.
. Pressoreceptors in aortic arch and carotid sinus
. Chemoreceptors in aortic arch and carotid sinus ( monitors low osygen by checking for high hydrogen ions. High carbon dioxide levels lead to high hydrogen ion concentratoin. This causes basoconstriction of non-essential vessels.
. Higher brain centers- emotions
. Autoregulation

Front 33

Autoregulation

Back 33

Oxygen is the principal stimulant. Low oxygen causes vasodialtor substances to be released. Examples are K+, H+, CO2, lactic acid, and adenosine. this cause local dilation and relaxationof precapillary sphincter muscles.

high CO2 high H+ causes low O2 vise a versa

Front 34

Venous pressure

Back 34

High in venules (16 mm Hg) and lowest at junction of vena cava with right atrium ( 0 mm Hg)
. Aid venous blood returning to heart

Front 35

Aid venous blood returning to heart

Back 35

. Pressure differences
. Sympathetic nerve activity
. Skeletal muscle pump
. Pressure difference between thoracic and abdominal cavities

Front 36

Velocity of blood in inversely related to TOTAL cross-sectional area and speed

Back 36

. Aorta , cross-sectional area of 4500-6000 cm2 and velocity of .1 cm/sec.
. Vena cava, cross-sectional area of 8 cm2 and velocity of 5 to 20 cm/sec.

Front 37

Distribution of Blood

Back 37

. Systemic veins- 60%
1. Act as blood reservoirs
2. Veins have thinner, less muscular walls, therefore higher comliance. This means that given amount of blood causes more distention in veins.
. Systemic arteries- 13%
. Capillaries- 7%
. Head and Lungs- 20%

Front 38

Capillary Exchange

Back 38

. Exchange dependent on pressure
. Efective filtration pressure
. Straling's Law of the Capillaries

Front 39

Exchange dependent on pressure

Back 39

. Blood Hydrostatic Pressure
. Intersititial Fluid Hydrostatic Pressure
. Blood Osmotic Pressure
. Interstitial Fluid Osmotic Pressure

Front 40

Blood Hydrostatic Pressure

Back 40

Blood pressure in capillaries average 35mm Hg at arterial end and 16mm Hg at venous end

Front 41

Interstitial Fluid Hydrostatic Pressure-

Back 41

Pressure of fluid aginst cells of tissue and capillaries. Average O mm Hg

Front 42

Blood Osmotic Pressure

Back 42

Due to large nubver of plasma proteins in blood. Moves fluid into capillaries. Averages 26 mm Hg at both ends

Front 43

Interstitial Fluid Osmotic Pressure

Back 43

Due to small number of proteins in Interstitial fluid. Averages 1 mm Hg at both ends

Front 44

Effective filtration pressure

Back 44

Direction of fluid movement Peff= (BHP+IFOP)-(IFHP+BOP). If the calculations equal a positive number, fluid is flowing from the capillary to the interstitial fluid, but if the calcuations equal a negative number fluid is flowing from the interstitial fluid to capillary

Front 45

Starling's Law of the Capillaries

Back 45

Amount flowing out of the arterial end almost equal the amount flowing in the venous end and the amount flowing in the lymphatic capillary

Front 46

Pulse

Back 46

Alternate expantion and recoil of artery as blood passes through.

Front 47

Average pulse

Back 47

60-80 beats per min

Front 48

Tachycardia

Back 48

rapid pulse over 100 beats per min at rest

Front 49

Bradycardia

Back 49

slow pulse, under 50 beats per min at rest

Front 50

Blood pressure

Back 50

pressure of blood in arteries
espressed as 120/80
. Top number represents pressuer of blood in arteries during systole
. bottome number represents pressure of blood in arteries during diastole
. difference in two numbers is called the pulse pressure
. ration of systolic pressure to diastolic pressure to pulse pressure should be 3:2:1.

Front 51

Types of Circualtion

Back 51

Systemic
Coronary
Hepatic portal circulation
Circles of Willis
Fetal circulation

Front 52

Systemic

Back 52

all oxygenated blood leaving left ventricle and returning to right atrium.

Front 53

Hepatic portal circulation

Back 53

veins that drain blood from capillaries in intestines, pancreas, spleen, stomach and gall bladder drain into capillaries in liver. The hepatic vein drains blood from liver and empties blood into inferior vena cava

Front 54

Circles of Willis

Back 54

provides alternate pathway for blood to reach brain in case of arterial occlusion. Also aids in equalizing blood pressure to brain

Front 55

Fetal circulation

Back 55

special structures associated with fetus

Front 56

Pulmonary

Back 56

all deoxygenated blood leaving the right ventricle and returning to left atrium