Aphy102 - Marieb - Chapter 19 - Blood Vessels

Front 1

Blood is carried in a closed system of vessels that begins and ends at the _____.

Back 1

Heart

Front 2

What are the three types of blood vessels?

Back 2

Arteries, Veins, Capillaries

Front 3

What do arteries do?

Back 3

Arteries carry blood away form the heart

Front 4

What do veins do?

Back 4

Veins carry blood toward the heart

Front 5

What do capillaries do?

Back 5

Capillaries contact tissue cells and directly serve cellular needs

Front 6

Arteries and veins are composed of what three "tunics?"

Back 6

1) Tunica interna
2) Tunica media
3) Tunica externa

Front 7

What's the innermost layer of a vein or artery called?

Back 7

Tunica interna

Front 8

What's the outermost layer of a vein or artery called?

Back 8

Tunica externa

Front 9

What's the second deepest layer of a vein or artery called?

Back 9

Tunica media (it's also the second most superficial. It lies in the middle)

Front 10

What are capillaries composed of?

Back 10

Endothelium with sparse basal lamina

Front 11

What type of blood vessels are simply composed of endothelium with sparse basal lamina?

Back 11

Capillaries

Front 12

What's the lumen of a vein or artery?

Back 12

The central blood-containing space.

Front 13

What's the central blood-containing space of a vein or artery called?

Back 13

Lumen

Front 14

What word describes the innermost layer of an organ, like the tunica interna?

Back 14

Intima

Front 15

What are the three layers of the tunica interna, from deepest (closest to lumen) to most superficial?

Back 15

1) Endothelium
2) Subendothelial layer
3) Internal elastic lamina

Front 16

What layer contains the external elastic lamina?

Back 16

The tunica media

Front 17

What are the elastic (conducting) arteries?

Back 17

Thick-walled arteries near the heart; the aorta and its major branches

Front 18

What arteries are described as "thick-walled arteries near the heart; the aorta and its major branches?"

Back 18

The elastic, or conducting, arteries

Front 19

What four characteristics make the elastic (conducting) arteries unique?

Back 19

1) Large lumen allow low-resistance conduction of blood

2) All three tunics contain elastin

3) They can withstand and normalize large fluctuations in pressure

4) They allow blood to flow fairly continuously through the body

Front 20

What's another word for elastic arteries?

Back 20

Conducting arteries

Front 21

What's another term for conducting arteries?

Back 21

Elastic arteries

Front 22

What's another term for muscular arteries?

Back 22

Distributing arteries

Front 23

What's another term for distributing arteries?

Back 23

Muscular arteries

Front 24

What do muscular (distributing) arteries do?

Back 24

They deliver blood to body organs

Front 25

What two physical properties make muscular (distributing) arteries unique?

Back 25

1) Thick tunica media with more smooth muscle and less elastic tissue

2) Active in vasoconstriction

Front 26

What are arterioles?

Back 26

The smallest of arteries; arteries that lead to the capillary beds

Front 27

What arteries are the smallest, and lead to capillary beds?

Back 27

Arterioles

Front 28

What important task are arterioles charged with?

Back 28

Controlling flow of blood to the capillary beds by vasoconstriction and vasodilation

Front 29

What are the smallest blood vessels?

Back 29

Capillaries

Front 30

What three physical properties make capillaries unique?

Back 30

1) They only have one tunic -- the tunica interna

2) The tunica interna is only one cell thick

3) They allow RBC's to flow through the capillary wall, one at a time.

Front 31

What are the three structural types of capillaries?

Back 31

1) Continuous

2) Fenestrated (from the latin "fenestra," meaning "window")

3) sinusoidal (noun = sinusoids)

Front 32

Where are continuous capillaries common?

Back 32

skin and muscles

Front 33

What are three physical properties that describe the continuous capillaries found in skin and muscles?

Back 33

1) They have endothelial cells that provide an uninterrupted lining

2) Adjacent cells are held together with tight junctions

3) There are intercellular clefts of unjoined membranes that allow the passage of fluids

Front 34

What type of capillary constitutes the blood-brain barrier?

Back 34

Continuous capillaries

Front 35

What special function do continuous capillaries in the brain serve?

Back 35

They make up the blood-brain barrier

Front 36

What physical property makes continuous capillaries in the brain unique?

Back 36

The endothelia of these capillaries are completely joined by tight junctions (no clefts).

Front 37

What's a pericyte?

Back 37

It's a relatively undifferentiated cell that is part of the epithelial tissue of a blood cell. It can transform into many types of cells when needed. Important in angiogenesis. Also called ROUGET'S CELL

Front 38

What do you call a type of relatively undifferentiated cell that helps make up the connective tissue around capillaries and other small blood vessels?

Back 38

Pericyte

Front 39

What's pinocytosis?

Back 39

the uptake of fluid and dissolved substances by a cell by invagination and pinching off of the cell membrane

Front 40

What three organs are most rife with fenestrated capillaries?

Back 40

Kidneys, endocrine glands, small intestines

Front 41

What are fenestrated capillaries particularly good at?

Back 41

active absorption and filtrate formation

Front 42

What physical properties are unique to fenestrated capillaries?

Back 42

1) an endothelium riddled with pores, called fenestrations. Remember, fenestra is latin for "window."

2) Greater permeability to solutes and fluids than other capillaries

Front 43

What's a quick description of a sinusoidal capillary (or a sinusoid blood vessel)?

Back 43

A highly modified, leaky, fenestrated capillary with a large lumen

Front 44

Where are sinusoidal capillaries found?

Back 44

Bone marrow, liver, lymphoid tissue, some endocrine organs

Front 45

What things make sinusoid blood vessels (sinusoidal capillaries) unique?

Back 45

1) They allow large cells like proteins and RBCs to pass relatively freely.

2) Blood flows sluggishly within them, allowing for modification in various ways.

3) They have incomplete basement membranes and large intercellular clefts

Front 46

What structure in the capillary bed connects the metarteriole directly to the postcapillary venule?

Back 46

Thoroughfare channel

Front 47

What structure separates true capillaries from the metarteriole at the capillary bed?

Back 47

Precapillary sphincters

Front 48

Describe a precapillary sphincter

Back 48

It's a cuff of smooth muscle that surrounds each true capillary and regulates flow into the capillary

Front 49

What structure regulates flow to true capillaries?

Back 49

Precapillary sphincter

Front 50

What two types of stimuli control blood flow at the capillary bed?

Back 50

1) Vasomotor nerve impulses

2) Local chemical changes

Front 51

What two types of vessels compose the capillary bed?

Back 51

1) True capillaries (10 to 100 of them)

2) Thoroughfare channels (vascular shunts) -- allow capillary bed to be bypassed

Front 52

What's a metarteriole?

Back 52

Any of the tiny blood vessels that connect the smallest arterioles to the capillary bed. Also called "precapillary."

Front 53

What type of blood vessel does a metarteriole branch off of?

Back 53

Terminal arteriole

Front 54

Terminal arterioles feed many tiny _____, blood vessels that connect to the capillary bed.

Back 54

Metarterioles

Front 55

What's a venule?

Back 55

Any of the minuscule veins that connect the capillary bed to larger systemic veins

Front 56

What's unique about a venule?

Back 56

A venule is extremely porous -- much like a capillary -- and allows WBCs and fluids to easily pass into body tissue from the bloodstream

Front 57

Which venules are the smallest venules?

Back 57

Postcapillary venules

Front 58

Describe postcapillary venules

Back 58

They're the smallest venules, composed of endothelium and a few pericytes. They are also very porous.

Front 59

How many layers of smooth muscle do large venules have?

Back 59

one or two (in the tunica media)

Front 60

What are postcapillary venules composed of?

Back 60

A single layer of epithelium around which a few pericytes congregate

Front 61

What is formed when venules converge?

Back 61

A vein

Front 62

In a vein, what's thinner: the tunica media or the tunica externa?

Back 62

The tunica media is thinner. The tunica externa is thick and contains collagen fibers and elastic networks.

Front 63

What tunic of a vein contains collagen fibers and elastic networks?

Back 63

The thick tunica externa

Front 64

Blood veins are also referred to as ____ _____ since they hold 65% of the blood supply.

Back 64

Capacitance vessels, blood reservoirs

Front 65

Where will you find the blood pressure to be higher: in a vein, or in an artery?

Back 65

Artery. Veins have MUCH lower blood pressure

Front 66

Which has thinner walls -- veins or arteries?

Back 66

Veins have thinner walls

Front 67

Which has thicker walls -- veins or arteries?

Back 67

Arteries have thicker walls

Front 68

What special adaptations do veins demonstrate, assisting with blood flow back to the heart?

Back 68

1) Large-diameter lumens
2) Valves (resembling semilunar heart valves) which prevent backflow

Front 69

What's a venous sinus?

Back 69

A venous sinus is a specialized, flattened vein with extremely thin walls (e.g., coronary sinus of the heart and dural sinuses of the brain).

Front 70

The pumping action of the heart generates blood flow through the vessels along a ____ ____, always moving from ____- to _____-pressure areas

Back 70

pressure gradient, higher, lower

Front 71

What other statistic is "blood flow" equivalent to when you're considering the entire cardiovascular system?

Back 71

Cardiac output (CO)

Front 72

What differs blood flow from cardiac output?

Back 72

Blood flow can be localized; i.e. specific organs can all have widely varying amounts of blood flow at any given time. Cardiac output is system-wide

Front 73

What two factors result in blood pressure?

Back 73

Blood flow and resistance. That's pressure for you.

Front 74

Describe systemic pressure.

Back 74

1) Highest in the aorta

2) Declines throughout length of pathway

3) It's 0 mm Hg in the right atrium

Front 75

Where does the steepest change in blood pressure occur?

Back 75

Arterioles

Front 76

In arterioles, are changes in blood pressure exaggerated or de-emphasized?

Back 76

Exaggerated

Front 77

Where is blood pressure more consistent: in arteries or in veins?

Back 77

In veins

Front 78

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

Back 78

1) Elasticity

2) Amount of blood forced in

Front 79

Blood pressure in elastic arteries near the heart is ____, meaning it rises and falls

Back 79

Pulsatile

Front 80

Define systolic pressure

Back 80

Amount of pressure exerted on arterial walls during ventricular contraction

Front 81

Define diastolic pressure

Back 81

The lowest level of arterial pressure during a ventricular cycle

Front 82

What's a term that describes the lowest level of arterial pressure during a ventricular cycle?

Back 82

Diastolic pressure

Front 83

What term describes arterial blood pressure during ventricular contraction?

Back 83

Sytolic pressure

Front 84

How do you pronounce "systole?"

Back 84

Sis - toe - lee

Front 85

How do you pronounce "diastole?"

Back 85

Die - ass - toe - lee

Front 86

What's pulse pressure?

Back 86

The difference between systolic and diastolic pressure.

Front 87

What's a term defined as "the difference between systolic and diastolic pressure?"

Back 87

Pulse pressure

Front 88

What's MAP?

Back 88

"Mean arterial pressure." This is the figure that REALLY matters when considering amount of blood flow to tissues.

Front 89

What's an easy way to estimate MAP?

Back 89

MAP = diastolic pressure + 1/3 pulse pressure

Front 90

What range does capillary BP usually fall into?

Back 90

20-40 mm Hg

Front 91

What's desirable: low capillary BP or high capillary BP.

Why?

Back 91

Low capillary BP -- high BP would rupture the tiny fragile walls.

Low BP is sufficient to force filtrate out into interstitial space and distribute nutrients, gases, and hormones between blood and tissues.

Front 92

How much pressure is necessary to force filtrate out of capillaries into interstitial space, distribute nutrients, gases, and hormones between blood and tissues?

Back 92

Not much. That's why capillary BP is low.

Front 93

What's a decent estimate for the pressure gradient in the venous system?

Back 93

20 mm Hg

Front 94

How does a vein behave when cut?

Back 94

It will spill blood with an even flow

Front 95

How does an artery behave when cut?

Back 95

It spurts out gobs of blood with the heartbeat

Front 96

What two phenomena assist the venous system in returning blood to the heart, seeing as how venous BP is insufficient to do so?

Back 96

1) Respiratory pump - local veins are squeezed during breathing, suck blood toward the heart

2) Muscular pump - contraction of skeletal muscles "milk" blood towards the heart

Front 97

What prevents backflow during venous return?

Back 97

valves, dummy.

Front 98

What five factors influence blood pressure in general?

Back 98

1) Heart rate
2) Blood volume
3) Cardiac output (CO)
4) Resistance
5) Viscosity

Front 99

What branch of the autonomic nervous system increases activity in relation to the heart in order to stimulate increased heart rate?

Back 99

Sympathetic

Front 100

What two factors are the most important factors in creating resistance in a blood vessel?

Back 100

1) Size of vessel (smaller means more pressure)

2) Smoothness of vessel (rougher means more pressure)

Front 101

What's a term for narrowing of blood vessels?

Back 101

vasoconstriction

Front 102

What kinds of drugs can cause vasoconstriction, thus increasing BP?

Back 102

antihistamines, naphazoline nitrate, tetrahydrozoline hydrochloride

Front 103

What's a common vasodilator that can decrease BP and help prevent heart attacks?

Back 103

Nitroglycerin

Front 104

Does anemia increase or decrease blood pressure?

Back 104

If it is anemia due to low RBC concentration, it will decrease blood pressure

Front 105

What artery do we use to measure blood pressure? What artery is our "benchmark?"

Back 105

brachial artery

Front 106

BP in other blood vessels is ____ than arterial BP.

Back 106

Lower

Front 107

What's the average BP in a healthy adult?

Back 107

120/80 mm Hg

(systolic comes first, diastolic comes last)

Front 108

What two factors are the main causes of hypertension (high BP)?

Back 108

1) Heart pumping with excessive force

2) Arterioles become narrower

Front 109

What's hypotension?

Back 109

Low blood pressure -- and it's usually a good sign. Unless, of course, it's chronic and due to malnutrition, addison's disease, or hypothyroidism.

Also, if it's acute, it's the clearest sign of circulatory shock

Front 110

What's the vasomotor center?

Back 110

The vasomotor center is a cluster of sympathetic neurons in the medulla that oversees changes in blood vessel diameter. Innervates SMOOTH MUSCLE, especially in arterioles

Front 111

What's the cardiovascular center?

Back 111

The vasomotor center plus the cardiac centers in the medulla that together regulate BP by altering CO and blood vessel diameter

Front 112

What's a baroreceptor?

Back 112

It's a receptor that can detect changes in blood pressure and communicate messages about these changes to the brain

Front 113

What are the types of baroreceptors?

Back 113

High pressure arterial baroreceptors and low pressure (cardiopulmonary) baroreceptor

Front 114

What sort of receptor can sense changes in blood pressure and communicate messages about blood pressure to the brain?

Back 114

Baroreceptors

Front 115

Describe the chain of events that occurs when BP strays higher than nominal levels.

Back 115

1) Baroreceptors detect the change, setting off the baroreceptor reflex

2) Cardioregulatory center increases parasympathetic stimulation of the heart while decreseaing sympathetic stimulation

3) Simultaneously with number 2, the vasomotor center decreases sympathetic stimulation of blood vessels

4) Stroke volume decreases, thus CO decreases. Vasodilation occurs, decreasing pressure. BP is reduced

Front 116

Describe the chain of events that occurs when BP strays lower than nominal levels.

Back 116

1) Change is detected by baroreceptors, setting of both the baroreceptor reflex AND the adrenal medullary mechanism

2) Due to baroreceptor reflex, parasympathetic stimulation of the heart is decreased, and sympathetic stimulation increased at the cardioregulatory center -- also, the vasomotor center increases sympathetic stimulation of blood vessels

3) At the same time, the adrenal medullary mechanism causes secretion of norepinephrine and and epinephrine from the adrenal medulla -- this is all due to increased sympathetic stimulation.

4) All the above measures cause vasoconstriction and increased HR, increasing BP

Front 117

What prominent chemicals increase blood pressure?

Back 117

1) Adrenal medulla hormones (epinephrine and norepinephrine)

2) Antidiuretic hormone (ADH) is a vasoconstrictor

3) Angiotensin II (released by kidney and is INTENSE as a vasoconstrictor)

4) Endothelium and prostoglandin-derived growth factor (PDGF) are vasoconstrictors

Front 118

What chemicals decrease blood pressure?

Back 118

1) Atrial natriuretic peptide (ANP)

2) Nitric oxide (NO) - brief but potent vasodilator

3) histamine, prostacyclin, kinins -- inflammatory chemicals in general

4) Alcohol, since it inhibits antidiuretic hormone (ADH)

Front 119

What chain of events occurs when blood pH strays higher than nominal levels? (this is often caused by a decrease in blood CO2)

Back 119

1) CHEMORECEPTOR REFLEX: chemoreceptors in the medulla oblongata detect the pH change

2) Vasomotor center decreases sympathetic stimulation of blood vessels and the cardioregulatory center increases parasympathetic activity while decreasing sympathetic stimulation of the heart.

3) Vasodilation occurs and CO decreases, because the body knows that low CO2 levels mean that too much blood is traveling to the lungs and thus decreases BP

Front 120

What chains of events occur when blood pH strays lower than nominal levels? (often caused by an increase in CO2 or a large decrease in O2)

Back 120

1) CHEMORECEPTOR REFLEX: Carotid and aortic bodies have chemoreceptors that detect the change. This reflex increases sympathetic stimulation of blood vessels and increased respiration rate (which in turns increases sympathetic stimulation of the heart and decreases parasympathetic stimulation of the heart). Vasoconstriction occurs and increases resistance while CO increases, increasing BP.

2) CHEMORECEPTOR REFLEX in the medulla oblongata -- cardioregulatory cetner increases CO by decreasing parasympathetic stimulation of the heart and increasing sympathetic stimulation

3) CNS - ISCHEMIC RESPONSE - chemoreceptors sense the pH change and the vasomotor increases sympathetic stimulation of blood vessels, constricting them and creating more resistance

FINALLY increased BP and CO cause more blood flow to lungs, fixing the problem, we hope.