Cardiovascular System: Blood Vessels

Front 1

CHAPTER 19: CARDIOVASCULAR SYSTEM- BLOOD VESSELS

Back 1

CHAPTER 19: CARDIOVASCULAR SYSTEM- BLOOD VESSELS

Front 2

Define blood vessels

Back 2

Delivery system of dynamic structures that begins and ends at the heart

Front 3

3 Main Structures of Blood Vessels

Back 3

Arteries- carry blood AWAY from the heart; oxygenated except for pulmonary circulation & umbilical vessels of a fetus

Capillaries- contact tissue cells and directly serve cellular needs

Veins- carry blood TOWARD the heart.

Front 4

What 2 things are composed of 2 tunics?

Back 4

Arteries and Veins

1. Tunica Interna (intima)
2. Tunica Media (**remember M for Muscle layer)
3. Tunica Externa (adventitia)

Front 5

What is central blood that contains space surrounded by tunics?

Back 5

Lumen

Front 6

What are capillaries composed of?

Back 6

Endothelium with sparse basal lamina

Front 7

Describe Tunica Interna (tunica intima)

Back 7

Endothelial layer that lines the lumen of all vessels

Front 8

Describe Tunica Media

Back 8

-Smooth muscle and elastic fiber layer, regulated by symathetic nervous system

-Controls vasoconstriction/ vasodilation of vessels

Front 9

Describe Tunica Externa (tunica adventita)

Back 9

-Collagen fibers that protect & reinforce vessels

-Larger vessels contain vasa vasorum "vessels of the vessels"- nourish the external tissues of the blood vessel wall.

Front 10

Describe Elastic (conducting) Arteries

Back 10

-Thick walled arteries near the heart
-Aorta and its major branches
-Large lumen allow low-resistance conduction of blood
-Contain ELASTIN in all 3 tunics
-Act as pressure reservoirs, expand and recoil as blood is rejected from the heart.

**Pressure highest**

Front 11

Describe Muscular (distributing) Arteries

Back 11

-Distal to elastic arteries
-Deliver blood to body organs
-Have thick tunica media with more smooth vessel
-Active in vasoconstriction

Front 12

What are arterioles?

Back 12

-The smallest arteries

-lead to capillary beds

-control flow into capillary beds via vasodilation & vasoconstriction.

Front 13

Capillaries: structure/function/describe

Back 13

-Microscopic blood vessels
-Walls of thin tunica intima, 1 cell thick
-Pericytes help stabilize their walls & control permeability
-Size allows only single RBC's to pass at a time
-In all tissues except for cartilage, epithelia, cornea and lens of eye
-Functions: exchange of gases, nutrients, wastes, hormones, etc.

Front 14

Do arteries have valves?

Back 14

No

Front 15

What are 3 structural types of capillaries?

Back 15

1. Continuous Capillaries
2. Fenestrated Capillaries
3. Sinusoidal Capillaries

Front 16

Describe Continuous Capillaries

Back 16

-Abundant in the skin and muscles
-Continuous capillaries of the brain

Front 17

Describe Fenestrated Capillaries

Back 17

Some endothelial cells contain pores (fenestrations)

More permeable than continuous capillaries

Function in absorption or filtrate formation (small intestines, endocrine glands, and kidneys)

Front 18

Describe Sinusoidal Capillaries

Back 18

Fewer tight junctions, larger intercellular clefts, large lumens

Usually fenestrated

Allow large molecules and blood cells to pass between the blood and surrounding tissues

Found in the liver, bone marrow, spleen

Front 19

How does the Blood Flow Through Capillary Beds

Back 19

Through the Precapillary sphincter

-Cuff of smooth muscle that surrounds each true capillary
-Regulates blood flow into the capillary

Front 20

When are venules formed and what do they allow?

Back 20

-Venules are formed when capillary beds unite

-Allow fluids and WBCs to pass from the bloodstream to tissues

Front 21

What are the smallest venules and what are they composed of?

Back 21

Postcapillary venules – smallest venules, composed of endothelium and a few pericytes

Front 22

Large venules have how many layers of smooth muscle also known as?

Back 22

Large venules have one or two layers of smooth muscle (tunica media)

Front 23

___a___ have much lower blood pressure and thinner walls than ___b___

Back 23

a. veins
b. arteries

Front 24

To return blood to the heart, veins have special adaptations, what are they?

Back 24

-Large-diameter lumens, which offer little resistance to flow

-Valves (resembling semilunar heart valves), which prevent backflow of blood

Front 25

What are Venous sinuses ?

Back 25

specialized, flattened veins with extremely thin walls (e.g., coronary sinus of the heart and dural sinuses of the brain)

Front 26

What are Vascular Anastomoses? Where are they more common?

Back 26

-Merging blood vessels

-More common in veins than arteries

Front 27

What do Arterial anastomoses provide ?

Back 27

-Arterial anastomoses provide alternate pathways (collateral channels) for blood to reach a given body region

*If one branch is blocked, the collateral channel can supply the area with adequate blood supply

Front 28

Actual volume of blood flowing through a vessel, an organ, or the entire circulation in a given period:

Back 28

-Is measured in ml per min.

-Is equivalent to cardiac output (CO), considering the entire vascular system

-Is relatively constant when at rest

-Varies widely through individual organs

Front 29

What is Blood Pressure? How is it expressed? What is it measured in reference to?

Back 29

-Force per unit area exerted on the wall of a blood vessel by its contained blood

-Expressed in millimeters of mercury (mm Hg)

-Measured in reference to systemic arterial BP in large arteries near the heart

Front 30

Opposition to flow is aka:

Back 30

Resistance

Front 31

Resistance measures the amount of

Back 31

friction blood encounters

Front 32

Resistance is referred to as:

Back 32

peripheral resistance (PR)

Front 33

The three important sources of resistance are:

Back 33

1) Blood viscosity
2) Total blood vessel length
3) Blood vessel diameter

Front 34

Factors that remain relatively constant during resistance:

Back 34

1. Blood viscosity-
The “stickiness” of the blood due to formed elements and plasma proteins

2. Blood vessel length-
The longer the vessel, the greater the resistance encountered

Front 35

What are the major determinants of peripheral resistance?

Back 35

Small-diameter arterioles are the major determinants of peripheral resistance

Front 36

Abrupt changes in diameter or fatty plaques from _______a_____ dramatically increase resistance

Back 36

a. atherosclerosis

**Disrupt blood flow and cause turbulence

Front 37

Relationship Between Blood Flow, Blood Pressure, and Resistance:

Blood flow (F) is directly proportional to the blood (hydrostatic) pressure gradient (P)

Back 37

If P increases, blood flow speeds up

Front 38

Relationship Between Blood Flow, Blood Pressure, and Resistance:

Blood flow is inversely proportional to peripheral resistance (R)

Back 38

If R increases, blood flow decreases

Front 39

What is more important in influencing local blood flow because it is easily changed by altering blood vessel diameter?

Back 39

Resistance

Front 40

What is Systemic Blood Pressure? What generates blood flow?

Back 40

-The pumping action of the heart generates blood flow

-The pumping action of the heart generates blood flow

Front 41

Systemic pressure is highest in the? Declines throughout the? Is 0 mm Hg in which atrium?

Back 41

-Is highest in the aorta

-Declines throughout the pathway

-Is 0 mm Hg in the right atrium

Front 42

Arterial BP reflects two factors of the arteries close to the heart, what are they?

Back 42

1. Their elasticity (compliance or distensibility)

2. The amount of blood forced into them at any given time

Front 43

What are 3 kinds of Arterial Blood Pressure?

Back 43

1. Systolic Pressure

2. Diastolic Pressure

3. Mean arterial pressure (MAP)

Front 44

Define Systolic pressure:

Back 44

Systolic pressure – pressure exerted on arterial walls during ventricular contraction

Front 45

Define Diastolic pressure

Back 45

Diastolic pressure – lowest level of arterial pressure

Front 46

Define Mean arterial pressure (MAP)

Back 46

Mean arterial pressure (MAP): pressure that propels the blood to the tissues (average blood pressure in an individual)

Front 47

What are the Factors Aiding Venous Return:

Back 47

1. Respiratory “pump”: pressure changes created during breathing move blood toward the heart by squeezing abdominal veins as thoracic veins expand

2. Muscular “pump”: contraction of skeletal muscles “milk” blood toward the heart and valves prevent backflow

3. Vasoconstriction of veins under sympathetic control

Front 48

The main factors influencing blood pressure are:

Back 48

1. Cardiac output (CO)
2. Peripheral resistance (PR)
3. Blood volume

Front 49

Equation of Blood Pressure

Back 49

Blood pressure = CO x PR

Front 50

Cardiac Output (CO)

When resting..

When Under Pressure..

Back 50

1. Resting heart rate is controlled by the cardioinhibitory center via the vagus nerves

2. Under stress, the cardioacceleratory center increases heart rate and stroke volume

Front 51

Control of blood pressure:

-Short-term neural and hormonal controls

Back 51

Counteract fluctuations in blood pressure by altering peripheral resistance

Front 52

Control of blood pressure:

-Long-term renal regulation

Back 52

Counteracts fluctuations in blood pressure by altering blood volume

Front 53

What is the Cardiovascular center

Back 53

vasomotor center plus the cardiac centers that integrate blood pressure control by altering cardiac output and blood vessel diameter

Front 54

What does the Vasomotor center oversee?

Back 54

changes in blood vessel diameter

Front 55

Short-Term Mechanisms: Vasomotor Activity

Increased sympathetic activity causes?

Back 55

Vasoconstriction and a rise in BP

Front 56

Short-Term Mechanisms: Vasomotor Activity

Decreased sympathetic activity causes?

Back 56

BP to decline

Front 57

Short-Term Mechanisms: Chemical Controls

Blood pressure is regulated by ______a._____ reflexes sensitive to ____b____ and carbon dioxide. _____c____chemoreceptors are the ____d___ and ___e____ bodies

Back 57

a. chemoreceptor
b. oxygen
c. Prominent
d. carotid
e. aortic

Front 58

What are the Chemicals that Increase Blood Pressure?

Back 58

1. Adrenal medulla hormones – norepinephrine and epinephrine increase blood pressure – cause vasoconstriction and increase cardiac output

2. Antidiuretic hormone (ADH) (Vasopressin) – causes intense vasoconstriction in cases of extremely low BP

3. Angiotensin II – kidney release of renin generates angiotensin II, which causes vasoconstriction

Front 59

What are the Chemicals that decrease Blood Pressure?

Back 59

1. Atrial natriuretic peptide (ANP) – causes blood volume and pressure to decline (produced by atria of the heart)

2. Nitric oxide (NO) – is a brief but potent vasodilator

3. Inflammatory chemicals – ex) histamine ( a vasodilator)

4. Alcohol – causes BP to drop by inhibiting ADH

Front 60

How does Long-term mechanisms control BP ?

Back 60

By Altering Blood Volume

Front 61

What acts directly and indirectly to maintain long-term blood pressure?

Back 61

The Kidneys

Front 62

How does the Kidneys directly and indirectly maintain long term BP?

Back 62

1. Direct renal mechanisms alters blood volume.

2.Indirect renal mechanism involves the reningiotensin mechanism.

Front 63

Direct Renal Mechanism

-Increased BP causes the Kidneys to..

-Decreased BP causes the Kidneys to..

Back 63

-Increased BP or Blood Volume causes the kidneys to eliminate more urine, thus reducing BP.

-Decreasing BP or Blood Volume causes the kidneys to conserve water, and BP rises.

Front 64

Define Vital Signs

Back 64

pulse and blood pressure, along with respiratory rate and body temperature

Front 65

Define Pulse

Back 65

pressure wave caused by the expansion and recoil of elastic arteries

-Radial pulse (taken on the radial artery at the wrist) is routinely used
-Varies with health, body position, and activity

Front 66

Efficiency of the circulation can be assessed by

Back 66

taking pulse and blood pressure measurements

Front 67

______a______ is measured indirectly with the auscultatory method

Back 67

a. Systemic arterial BP

Front 68

What is the the auscultatory method?

Back 68

1. A sphygmomanometer is placed on the arm superior to the elbow

2. Pressure is increased in the cuff until it is greater than systolic pressure in the brachial artery

3. Pressure is released slowly and the examiner listens with a stethoscope

Front 69

Measuring Blood Pressure:

1. The first sound heard is recorded as _______a______.

2. The pressure when sound disappears is recorded as the ________b_________.

Back 69

a. the systolic pressure (systolic pressure, normally 110–140 mm Hg)

b. diastolic pressure (diastolic pressure, normally 70–80 mm Hg)

Front 70

Describe some Variations in Blood Pressure

Back 70

1. Blood pressure cycles over a 24-hour period

2. BP peaks in the morning due to levels of hormones

3. Extrinsic factors such as age, sex, weight, race, mood, posture, socioeconomic status, and physical activity may also cause BP to vary

Front 71

Term for Low Blood Pressure

Back 71

Hypotension, which is an alteration in BP.

Front 72

Hypotension is often associated with

Back 72

long life and lack of cardiovascular illness

Front 73

When Hypotension occurs, what is the Systolic Pressure?

Back 73

Below 100 mm Hg

Front 74

Define Orthostatic hypotension

Back 74

*Homeostatic Imbalance

-temporary low BP and dizziness when suddenly rising from a sitting or reclining position

Front 75

Define Chronic hypotension

Back 75

*Homeostatic Imbalance

-hint of poor nutrition and warning sign for Addison’s disease (adrenal isnsufficiency) or hypothyroidism

Front 76

Acute hypotension is an important sign of:

Back 76

*Homeostatic Imbalance

circulatory shock

Front 77

Term for High Blood Pressure

Back 77

Hypertension, which is an alteration in BP.

Front 78

When Hypertension occurs, Sustained elevated arterial pressure is..

Back 78

-140/90 or higher

Front 79

Hypertension is common in...

Back 79

Obese People

Front 80

Prolonged hypertension is a major cause of:

Back 80

heart failure, vascular disease, renal failure, and stroke

Front 81

Primary or essential hypertension is what % of hypertensive conditions? What is it due to?

Back 81

1. 90%

2. to several risk factors including heredity, diet, obesity, age, stress, diabetes mellitus, and smoking

Front 82

Secondary Hypertension is more or less common then primary hypertension? What is it due to?

Back 82

1. Less

2. identifiable disorders, including kidney disease, arteriosclerosis, and endocrine disorders such as hyperthyroidism and Cushing’s syndrome (hyperadrenalism)

Front 83

Define Autoregulation

Back 83

automatic adjustment of blood flow to each tissue in proportion to its requirements at any given point in time

Front 84

When does angiogenesis occur? When is it common in the heart?

Back 84

1. Occurs when short-term autoregulation cannot meet tissue nutrient requirements
1.The # of vessels to a region increases.
2. existing vessels enlarge

2. Common in heart when a coronary vessel is occluded and throughout the body in people in high altitude areas.

Front 85

When does muscle blood flow increase?

Back 85

It increases tenfold or more during physical activity as vasodilation occurs