VESSELS* CH 20 Flashcards by Gilberto Talamantes

Identify and describe the three layers of vessels from least to most superficial (inside to out)

Tunica Intima - simple squamous epithelium; keeps blood cells from sticking

Tunica Media - Smooth Muscle; vasodilation and vasoconstriction

Tunica Externa - Collagen fibers anchors the vessel to surrounding tissue

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Small vessels that supply blood to outer half of wall in the larger vessels

Vasa Vasorum

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A - Tunica Interna
B - Tunica Media
C - Tunica Externa

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What type of tissue makes up capillaries? What tunic contains this same tissue

Simple Squamous Epithelium
TUNICA INTERNA

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Identify and describe the components of an aneurysm. What commonly causes it?

A weak point in an artery or within the heart wall that are likely to rupture causing hemorrhaging

Most commonly caused by atherosclerosis and HTN

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Identify and describe the arterial sense organs

Carotid Sinuses - Baroreceptors monitor blood pressure in the carotid artery

Carotid Bodies - Chemoreceptors monitor O2 and CO2 levels + pH in the carotid artery

Aortic Bodies - Chemoreceptors monitor O2 and CO2 levels + pH in the aortic arch

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Identify the function of pericytes

Stabilize the vessel wall + regulate permeability in continuous capillaries

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Identify and describe the capillary types

Continuous - Least leaky; found in skin and muscles

Fenestrated - More permeable than continuous capillaries; found in organs that require rapid absorption + filtration: Kidneys + Small Intestine

Sinusoid - Most leaky, contain blood filled spaces + large fenestrations; found in liver, bone marrow, spleen

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Pressure in Veins vs Arteries

Veins are steady, slow, and continuous unlike arteries

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At any given point in time, where is most of the blood found within the body?

Veins

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What causes varicose veins?

Blood pools in veins if you stand for too long;
More prone: Hereditary Weakness, Obesity, Pregnancy

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What is the most common pathway of blood starting at the heart?

Heart
Arteries
Arterioles
Capillaries
Venules
Veins

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Describe a portal system

Blood flows through two consecutive capillary netwroks before returning to heart

B in the image

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What is an anastomosis? What are the different types?

Convergence between two vessels not in a capillary

Arteriovenous Anastomosis - Artery to Vein

Venous Anastomosis - Vein to Vein (most common) (D)

Arterial Anastomosis - Artery to Artery (E)

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How are pressure, flow, and resistance related?

Flow = △ PRESSURE / RESISTANCE

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If you increase or decrease pressure, how does that affect flow? Is this relationship inversely or directly proportional?

Flow = △ PRESSURE / RESISTANCE

If you increase pressure, you increase flow

If you decrease pressure, you decrease flow

Directly proportional

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If you increase or decrease resistance, how does that affect flow? Is this relationship inversely or directly proportional?

Flow = △ PRESSURE / RESISTANCE

If you increase resistance, you decrease flow

If you decrease resistance, you increase flow

Inversely proportional

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Systolic vs Diastolic Pressure

Systolic - Peak arterial BP taken during ventricular systole

Diastolic - minimum arterial BP taken during ventricular diastole

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What is a normal BP value for a young adult

120/75

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Define atherosclerosis; how does it impact blood pressure?

The buildup of fats, cholesterol, ad other substances on the artery wall

Increases blood pressure to try to increase flow

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Define arteriosclerosis; how does it impact blood pressure?

The stiffening of arteries due to deterioration of elastic tissues

Increases blood pressure to try to increase flow

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Hypertension

Chonic high resting BP
(any of the two numbers)

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Hypotension

Chronic low resting BP
(any of the two numbers)

Orthostatic Hypotension

Temporary low BP and dizziness when suddenly rising from a sitting or reclined position

Chronic Hypoension

Hint of poor nutrition and a warning sing for addisons disease or hypothyroidism

Acute Hypotension

Severe temporary low BP; sign of circulatory shock (not any blood + oxygen flow through body)

What three variables determine blood pressure? How does changing any of these factors effect BP

- Cardiac Output - Blood volume - Resistance to flow These are all directly proportional to BP; if you increase any you increase BP, If you decrease any you decfrease BP

What is peripheral resistance?

The resistance of flow that blood encounters away from the heart

What three factors affect peripheral resistance?

Blood Viscosity Directly Proportional Vessel Length Directly Proportional Vessel Radius Inversely Proportional

Why does blood speed decrease from the aorta to the capillaries?

- It has traveled a greater distance - Smaller radius of arterioles and capillaries (increases resistance) - Number of vessels increase and blood encounters more resistance

Why does blood speed increase again as it travels through the veins? Does it regain the same speed as it did in the larger arteries?

Veins are larger and therefore the blood encounters less resistance No

List the three ways the body can control vasomotor activity

Local Control Neural Control Hormonal Control

LOCAL CONTROL ON VASOMOTOR ACTIVITY: Define Autoregulation

The ability of tissues to regulate their own blood supply by vasoconstricting or vasodilating

LOCAL CONTROL ON VASOMOTOR ACTIVITY: Define Vasoactive Chemicals

Substances secreted by platelets, endothelial cells, and perivascular tissues in response to resistance in order to stimulate + dilate vessels - Occurs during trauma, inflammation or exercise

LOCAL CONTROL ON VASOMOTOR ACTIVITY: Define Reactive Hyperemia

A short period of time following the period where blood supply is cut off and restored where flow increases above normal (to make up for what was lost)

LOCAL CONTROL ON VASOMOTOR ACTIVITY: Define Angiogenesis

The growth or creation of new blood vessels in response to damage (or natural shedding like after a woman's period)

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Define Baroreflex

Negative feedback in response to blood pressure; activated when BP gets too high

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Define Chemoreflex

Primary Role: Adjust respiration levels in response to a change or irregular concetration of CO2 or O2 Secondary Role: Vasodilation + Vasoconstriction

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Define Medullary Ischemic Reflex

Increase HR and BP to the heart in response to low oxygen levels to the brain

HORMONAL CONTROL ON VASOMOTOR ACTIVITY: Identify and describe the function + production of Angiotensin II

Angiotensin I > Angiotensin Converting Enzyme (ACE) > Angiotensin II It is a potent vasoconstrictor that raises blood pressure

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Identify the function of Aldosterone

Increase BP by retaining sodium + water in the kidneys

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Identify the function of Natriuretic Peptides

Secreted by the heart causing the kidneys to excrete sodium + water and has a vasodilator effect which both lower BP

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Identify the function of Antidiuretic Hormone (ADH)

Promotes water retention and raises BP

NEURAL CONTROL ON VASOMOTOR ACTIVITY: Identify the function of Epinephrine and Norepinephrine

Stimulates vasoconstriction and raises BP

What is edema?

Accumulation of excess fluid in a tissue

Identify and describe the three primary causes of edema

Increased Capilary Filtration- Too much liquid leaving the capillaries Reduced Capillary Reabsorption - Not enough fluid is being absorbed by the capillaries Obstructed Lymphatic Drainage - Lymphatic issues with draining excess fluid

What is venous return? Identify and describe the five mechanisms that help achieve this

Flow of blood back to the heart Pressure Gradient - difference in pressure that drives flow Gravity - Drains blood from the head to the neck Skeletal Muscle Pump - Moving muscles to help milk blood through the veins Thoracic Pump - Pressure changes that come from breathing allows blood to be sucked up to the heart Cardiac Suction - Suction draws blood from the vena cava into the atria GPS TC

What is circulatory shock?

Not getting enough blood to the body and back to the heart

Identify and describe the two types of circulatory shock

Cardiogenic Shock - Inadequate pumping of the heart Hypovolemic Shock - Most common; due to a loss of blood

-Capnia

Carbon Dioxide (CO2)

Hypercapnia

Too much carbon dioxide in the brain causes pH to drop + triggers vasodilation to get rid of CO2

Hypocapnia

Not enough carbon dioxide in the brain causes pH to increase + triggers vasoconstriction to retain more CO2

TIA vs CVA

Transient Ischemic Attack - Mini stroke often an early warning of an impending stroke to come Cerebrovascular Accident - Sudden death of brain tissue caused by a lack of blood + O2 to the brain

What is an air embolism?

Presence of air in the bloodstream; small amounts can cause a cardiac arrest

Primary vs Secondary Hypertension

Primary - Caused by obesity, poor diet, smoking (90% of Cases) Secondary - Caused by another underlying cause or disorder (10% of Cases)