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Anatomy & Physiology 210 > Chapter 20 Blood Vessels > Flashcards

Chapter 20 Blood Vessels Flashcards

1
Q

What are the three tunics of the vessel? What are each made of?

A

Tunica intima: endothelial lumen layer. (Vessels larger than 1mm have subendothelial connective tissue basement membrane).

Tunica media: smooth muscle and elastic fibers layer. (sympathetic controlls for Vaso constriction/dilation).

Tunica externa: collagen fibers for reinforcement. (Larger vessels contain vasa vasorum: tiny blood vessels to feed vessel).

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2
Q

What are the three types of arteries largest to smallest?

A

Elastic conducting arteries

Muscular arteries

Arterioles

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3
Q

Where would you find elastic arteries? What makes them special?

A

Thick walled (largest) arteries near the heart, I.e. aorta and major branches.

Large lumen=low resistance

Elastin in all three tunics

With stands and smoots large wood pressure fluctuations

Blood pressure reservoir (maintains pressure between beats)

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4
Q

Where would you find muscular arteries? What makes them special?

A

Distal to elastic arteries: deliver blood to body organs specifically.

Thick Tunica media with more smooth muscle

Active vasoconstriction (sym NS release Epi)

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5
Q

Capillaries are made for _______ and _________. And composed of ___________.

A

Diffusion and gas exchange

Endothelium (thinner membrane)

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6
Q

What are arterioles? What do they do?

A

Smallest arteries: lead to the capillary beds (dermis).

Control flow into capillary beds via vasodilation and constriction.

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7
Q

Capillaries are the __________ blood vessels.

What are the three structural types of capillaries?

A

Smallest

Continuous
Fenestrated
Sinusoids

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8
Q

Where are continuous capillaries most abundant? What type of cells create the lining, how are those connected, and what allows fluid passage?

A

Skin and muscles.

Endothelial cells, tight junctions, intercellular clefts.

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9
Q

Other than skin and muscles, where do you find a continuous capillary? What significant feature does it make up?

A

Brain. Tight junctions completely around endothelium.

Blood brain barrier

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10
Q

Where do you find fenestrated capillaries? What are three examples?
How are they different from continuous capillaries anatomically?

A

Wherever active capillary absorption/filtration occurs.
Small intestines, endocrine glands, and kidneys.

Endothelium with pores. Greater permeability.

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11
Q

Where are sinusoid capillaries found, Name four examples.
What makes them different anatomically from the other capillaries?
They allow large molecules to what?

A

Liver, bone marrow, lymphoid tissue, and spleen.

Very leaky, large lumen, large clefts.

Pass between the blood and surrounding tissues.

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12
Q

What are capillary beds made up of?

A

Networks of capillaries consisting of:

vascular shunt (Direct route from arteriole to post cap venule): 
metarteriole (artery) and throughfare channel (vein)

True capillaries: 10 to 100. Branch off metarteriole and return to throughfare channel.

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13
Q

What is a precapillary sphincter?

A

Cuff of smooth muscle that surrounds each true capillary.

Regulates capillary blood flow.

Regulated by vasomotor nerves and local chemical conditions.

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14
Q

What are venules?

What do they allow?

A

When capillary beds unite

Allows Fluids and wbc pass from bloodstream to tissue

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15
Q

What are post capillary venules?

What are they composed of?

What are large venue is composed of?

A

Smallest venules, composed of endothelium in a few pericytes.

Large Venules have layers of smooth muscle (Tunica media)

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16
Q

When do veins form?
What layers composed of?

What is Capacitance vessels?

A

When venules converge.

Three tunics

Blood reservoir 65% blood supply (pull extra blood)

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17
Q

Do veins have higher or lower pressure? Thinner or thicker walls?
What are the adaptations to allow veins to return blood to the heart?

A

Lower blood pressure, thinner walls

Larger lumen, less resistance.

Valves preventing backflow.

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18
Q

What are varicose vein, and causes?

A

Veins with incompetent valves.

Weight exerting pressure on groin. Restricts return blood flow from legs. Pooled blood stretches vein wall, creating an incompetent valves.

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19
Q

What are anastomoses?

Explain arterial anastomoses.

Give an example of an arterial venous anastomoses.

A

Merging of blood vessels.

Two arteries making vessel connection without capillary to supply blood to a body region.

Metarteriole-thoroughfare channel

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20
Q

What is blood flow? How is it measured and distributed?

A

Volume of blood flowing through a vessel/organ/circulation

Ml/min

Varies widely in organs/by tissue need.

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21
Q

What is blood pressure?

How is it measured?

Where is blood pressure the highest and lowest?

A

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

Mm of mercury

Highest – aorta
lowest – vena cava

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22
Q

What is resistance and how is it measured?

What is it referred to as? And what are the three sources of resistance?

A

Opposition to the flow. Measures amount of friction blood encounters with vessel wall.

Peripheral resistance (systematic circulation).

Blood viscosity, total blood vessel length, and blood vessel diameter.

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23
Q

The smallest _____________ (______________) Will have the highest resistance. The largest ________ (_________ ________) will have the lowest resistance.

A

Vessels (capillaries)

Lumens (large veins)

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24
Q

What are the major determinants of peripheral resistance?

A

Small diameter arterioles (have smooth muscle contraction, Tunica media)

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25
Q

What do fatty plaques from atherosclerosis do?

A

(hardened arteries)

Cause turbulent flow due to hitting hard plaques and causing back up RBCs. Vessels do not dilate, preventing 02 to tissue needing it.

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26
Q

If change in pressure increases blood flow ___________. If change in pressure decreases, bloodflow _________.

Bloodflow is inversely proportional to resistance. If resistance increases, bloodflow ___________.

_______________ is more important than change in pressure in influencing local blood pressure.

A

Increases

Declines

Decreases

Resistance

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27
Q

F =

A

F=(change)P
———–
R

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28
Q

What three major factors determine systemic blood pressure?

A

Blood volume:
short term – vasoconstriction (^BP)
long term – renal control of urinary output

Cardiac output:
HR
SV

Peripheral resistance:
Length of vessels
blood viscosity
vasoconstriction (^R)

29
Q

Systematic pressure is highest in the _________. Declines throughout the length of the __________. Is 0mm Hg in the ____________.

The steepest change in blood pressure occurs in the __________.

A

Aorta

pathway

vena cava/right atrium

arterioles (to smooth out manageable pressure for Capillaries)

30
Q

Arterial BP reflects two factors of the arteries close to the heart.

Blood pressure in elastic arteries near the heart is __________.

A

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

Pulsatile (BP rises and falls)

31
Q

Explain what each of the following represents.
Systolic pressure
diastolic pressure
pulse pressure
mean arterial pressure (and formula for MAP)

A

Systolic – pressure on arterial walls during the ventricular contraction (120)

Diastolic – lowest level of arterial pressure during ventricular cycle. (80)

Pulse - the diff between sys and dias

MAP - pressure that propels blood into tissues

Map+ Dias press + 1/3 pulse pressure

32
Q

Venous BP alone is too low to promote adequate blood return and has aided by the:

What prevents backflow?

A

Respiratory pump: pressure changes during breathing suck blood toward the heart (squeezing).

Muscular pump: skeletal muscle contraction milk blood toward heart

Valves prevent backflow

33
Q

Cardiac output is determined by?

Resting HR is controlled by?

Under stress the cardio acceleratory center does what?

A

Venous return
Neural (Epi) and hormonal (adh, aldos, angio) controls

Cardio inhibitory center (vagus nerve)

Increases HR and SV

34
Q

What are the short-term neural controls?

A

Neural controls a peripheral resistance:
Alter blood distribution in response to demand.
Maintain MAP by altering blood vessel diameter.

Neural controls operate via reflex arcs involving:
Borrow receptors.
Vasomotor centers and vasomotor fibers.
Vascular smooth muscle.

35
Q

What is the vasomotor center?

A

Cluster of sympathetic neurons in the Medulla, overseas blood vessel diameter. (Balance between dilations/constriction)

36
Q

What is the cardiovascular center?

A

Vasomotor center and cardiac centers that integrate blood pressure control by altering CO and blood vessel diameter
(Built in negative feedback system)

37
Q

Sympathetic activity, norepinephrine, causes?

How is vasomotor activity modified?

A

If increased: vasoconstriction and BP rises.

If decreased: BP to decline to basal levels.

Baroreceptors, chemo receptors, higher brain centers, blood-borne chemicals, and hormones.

38
Q

Increased blood pressure stimulates ___________ center to?

Declining blood pressure stimulates the ______________ center to?

A

Cardio inhibitory
Vasodilation: decrease HR, CO, PR, and BP.

Cardioacceleratory
Increase CO and PR.
(Low BP stimulates vasomotor center to constrict blood vessels.)

39
Q

Blood pressure is regulated by ___________ reflexes sensitive to oxygen and carbon dioxide.
And where are the two prominent ones?

Reflexes that regulate BPR integrated in the ________?

Higher brain centers can modify BP via relays to ______ _______?

A

Chemo receptor

Carotid and aortic bodies

Medulla

Medullary centers

40
Q

What are the chemicals that increase blood pressure?l

A

Adrenal Medulla hormones(Epi/nor):
Increase BP

ADH:
Intense vasoconstriction in low BP

Angiotensin II: kidney release renin makes angio II causing vasoconstriction

Endothelium derive factors: PDGF and endothelin vasoconstriction

41
Q

What are the chemicals that decrease blood pressure?

A

ANP:
Blood volume/pressure decline

NO:
potent vasodilator

Inflammatory chemicals:
(Histamine, prostacyclin, kinins)
Potent vasodilators

Alcohol:
Causing BP decrease inhibiting ADH

42
Q

Long term mechanisms control BP by altering blood volume, name how for both increased and decreased BP.

A

Increased: stimulates kidneys to eliminate water reducing BP

Decreased: stimulates kidneys to increased blood volume and BP

43
Q

What are the two ways kidneys act directly and indirectly to maintain long term blood pressure?

A

Direct renal mechanism: alters blood volume. Blood volume or pressure increases—urine output increases.

Indirect renal mechanism: Renin angiotensin mechanism (hormonal mechanism, need to drink more)

44
Q

What are the vital signs checked to monitor circulatory efficiency?

A

Pulse
BP
Respiratory rate
Body temp

45
Q

What is the pulse?

A

Pressure wave caused by expansion and recoil of elastic arteries

Radial pulse routinely used.

Varies with health, body position, and activity.

46
Q

How is BP measured physically?

A

Auscultatory method

Sphygmomanometer placed above elbow, pressure increased until greater than systolic pres in brachial artery. Pressure slowly released whiled listening with stethoscope.

47
Q

What are the Korotkoff sounds?

A

The first sound heard is recorded as the systolic pressure.

The pressure when the sound disappears is recorded as diastolic pressure.

48
Q

What are hypotension and hypertension?

Differentiate transient vs chronic elevation

A

Hypo-Low BP in which systolic pressure is low

Hyper-condition of sustained elevated arterial pressure

Transient: normal, can be caused by fever, physical exertion, and emotional upset.

Chronic: major cause of heart failure, vascular dz, renal failure, stroke.

49
Q

Three hypotension and explain.

A

Orthostatic hypo: temporary low BP and dizziness when rising suddenly (positional)

Chronic hypo: hint of poor nutrition, warning for Addison’s

Cute hypo: sign of circulatory shock (threat to icu pts and pts in surgery)

50
Q

Name the two hypertension and explain.

A

Primary or Essential hyper:
No cause, risk factors include: diet, obesity, age, race, heredity, stress, and smoking. 90%

Secondary hyper: due to identifiable disorders.
Excessive renin secretion, ateriosclerosis, endocrine disorders (cushings). 10%

51
Q

Blood flow (tissue perfusion) is involved in what 4 things?

A

Delivery of O2 and nutrients, removal of wastes, of tissue cells.

Ga exchange (lungs)

Absorption of nutrients (digestive tract)

Urine formation (by kidneys)

52
Q

What is autoregulation, local regulation of blood flow?

A

Automatic adjustment of blood flow to each to shoot in proportion to its requirements at any given point in time.

Intrinsically controlled modifying diameter of local arterioles feeding capillaries.

53
Q

MAP remains ____________, while local demands regulate the amount of blood delivered to various areas according to need.

A

Constant

54
Q

What are the two short-term autoregulation controls?

A 
Metabolic controls
Myogenic controls (positional)
55
Q

Explain the autoregulated metabolic control of blood flow.

A

Declined tissue nutrient and O2 stimulate.

Hemo delivers both O2 and NO
Inducing vasodilation at caps to get to tissue.

Other autoreg subs (active tissue local paracrines):
THESE OVERRIDE SNS
Potassium, hydrogen ions, adenosine, lactic acid, histamine, kinins, prostaglandins.

56
Q

Explain the autoreg myogenic controls.

A

Inadequate blood perfusion or excessively high pressure:
Are auto regulatory.
Provoke myogenic response -stimulate vascular smooth muscle

Vascular muscle response directly to:
Increased vascular pressure with increased tone, which causes vasoconstriction.
Reduce stretch with vasodilation, which promotes increased blood flow.

57
Q

What is angiogenesis? And how is it Evoked?

A

Number of blood vessels in region increased, newly grown to meet need.

Long term autoregulation, when short-term cannot meet requirements.

58
Q

Hyperemia is directly proportional to?

Arterioles have what kind of receptors? What do those bind to?

A

Greater metabolic activity of skeletal muscle.

Cholinergic, and alpha and beta adrenergic.
Chol-ACH (dilation)
Adr- Epi (constric)

59
Q

Blood flow to the brain is ________.

Explain the metabolic and myogenic controls of the brain.

Decreases/increases in _________ cause cerebral vessels to dilate/constrict to promote/protect

A

Constant

Metabolic: sensitive to pH declines. Increased CO causes vasodilation.

Myogenic: protects brain from damaging blood pressure changes.

MAP

60
Q

Being that the brain can regulate its own blood flow,such as ischemia caused by tumor, The brain is what under extreme systemic pressure changes?

MAP Extreme lows/highs can cause what?

A

Vulnerable.

Below 60 syncope (fainting)
Above 160 cerebral edema

*normal 93

61
Q

Blood flow to venous plexus is below the skin are controlled by what?

A

Amount controlled by body temperature.

SNS initiated by temperature receptors in the CNS.

62
Q

What happens to blood flow when temperature rises and decreases?

A

Rises: hypothalamus signals reduce vasomotor stimulation of skin vessels, heat radiates from skin.
*Bradykinin (paracrine released by sweat) stimulates the release of NO (vasodilation).

Decreases: blood shunted to vital organs

63
Q

The auto regulatory mechanism for the lungs is opp in most tissues that?

A

Low oxygen cause vasoconstriction; High promote dilation

  • this allows for prop for oxygen loading in lungs (airflow not blood flow)
64
Q

During strenuous exercise, heart vessels do what? This results in?

A

Vessels dilate in response to local accumulation of carbon dioxide.

Bloodflow increases 3 to 4 times. Remains constant despite wide variation due to metabolic controls.

65
Q

Direction and amount of fluid flow depends on the difference between what two things? Define each.

A

Hydrostatic pressure: pressure of blood against walls. (Force fluids through walls, greater at arterial end.)

Osmotic pressure: albumin (non-diffusible plasma proteins), which draws water towards itself.

66
Q

Define the formula for net filtration pressure. Which dominate each end of the capillary and allow what?

A

NFP =
{HP(cap out)-HP(tis in)}-{(OP(cap)-OP(tis)}

HP dominates arterial, fluids flow out

OP dominates venous end, fluids flow in

67
Q

What is circulatory shock?

A

Any condition where blood vessels are inadequately filled blood cannot circulate normally. Tissues needs not met.

68
Q

What are the three types of circulatory shock? Explain each.

A

Hypovolemic shock: Low blood volume (large-scale blood loss).

Vascular shock: poor circulation (Extreme vasodilation) TWO TYPES:
Anaphylactic shock – body wide vasodilation triggered by histamine release.
Septic shock – body wide Vasodilation triggered by bacterial toxins.

Cardiogenic shock: pump failure (heart cannot sustain adequate circulation)

Anatomy & Physiology 210 (21 decks)

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