Blood Vessels

Question 1

3 major typed of blood vessels

Answer 1

• Arteries: carry blood away from the heart (oxygenated blood)
• Veins; carry blood to the heart (deoxygenated blood)
• capillaries: directly exchange gases and nutrient with tissues to meet cellular demand

Question 2

Blood vessel walls

Answer 2

• Tunica interna (endothelium): reduces friction between the vessel walls & blood
• Tunica media (smooth muscle & elastin):controls vasoconstriction/dilation of the vessel
• Tunica externa (loosely woven collagen fibers): protects, reinforces, and anchors the vessel to surrounding structures

Question 3

Elastic Arteries

Answer 3

large amounts of elastin to allow the vessels withstand the pressure changes of the cardiac cycle

Question 4

Muscular arteries

Answer 4

Deliver blood to specific body organs and have the greatest proportion to tunica media of all vessel, making them more active in vasoconstrictions

Question 5

Arterioles

Answer 5

smallest arteries
Regulate blood flow into capillary beds through vasoconstriction/dilation

Question 6

Capillaries

Answer 6

Smallest vessels
- Allow for exchange of substance between the blood and interstitial fluids of tissue and organs
- Connect arterioles and venules

Question 7

Continuous capillaries

Answer 7

Most common
- Allow passage of fluids and smalls solutes
- In the brain, the intercellular clefts are replaced with tight junction to make the blood-brain barrier

Question 8

Fenestrated capillaries

Answer 8

More permeable to fluids & solutes than continuous capillaries
- This helps with absorption in the small intestines and flirtation in the kidneys

Question 9

Sinusoid capillaries

Answer 9

Leaky capillaries that allow large molecules to pass between the bcos,ood and surrounding tissues (liver, spleen or bone marrow)

Question 10

Anastomoses

Answer 10

A connection between blood cells that supplied blood to the same region of the body,
- Allow blood to have alternative routes to reach tissues and return back to the heart when one blood vessel is damaged/blocked

Question 11

Arteriovenous anastomosis

Answer 11

Anastomosis that occurs between an artery and a vein
- Non-anastomosing blood vessels in the same body region can also provide alternate circulation routes

Question 12

Metarterioles

Answer 12

Unique feature of the circulatory a system around the intestines
Pre-capillary sphincter: surrounds each capillary & acts as a valve to regulate blood flow into t he capillary/keep the blood in the thoroughfare channels

Question 13

Veins

Answer 13

Venules: formed where capillaries converge and allow fluid and white blood cells to move easily between blood & tissues
Join to form veins

Question 14

Blood flow

Answer 14

• Volume of blood flowing through a vessel, organ, or the entire circulation in a given period and may be expressed as mL/min
• Blood pressure: force per unit area exerted by the blood against a blood vessel wall and is expressed in (mmHg)

Question 15

Resistance

Answer 15

A measure of the friction between blood and the blood vessel walls. Related to blood viscosity, vessel length, vessel diameter

Question 16

Flow, pressure & resistance

Answer 16

• If blood pressure increases, blood flow increases
• resistance increases, blood flow decreases

Question 17

Peripheral circulation

Answer 17

• Generally refers to circulation in all of the blood vessels outside of the heart and coronary vessels

Question 18

Peripheral resistance

Answer 18

• the most important factor influencing local blood flow
• vasoconstriction/dilation can dramatically alter local blood flow, while systemic blood pressure remains unchanged

Question 19

Blood pressure

Answer 19

• Decreases as blood flows from arteries through capillaries and into veins
• Blood pressure results when blood flow is opposed by resistance

Question 20

Systemic blood pressure

Answer 20

• Highest in the aorta and declines throughout the pathways until it reaches 0 mmHg in the right atrium

Question 21

Arterial blood pressure

Answer 21

• Relatively high because the arteries close to the heart can be stretched. A large volume of blood is forced into them at during ventricular systole
• Systolic pressure: a peak in pressure produced when the left ventricle contracts, blood is forced into the aorta, which averages 120mmHg

Question 22

Diastolic pressure

Answer 22

• Occurs when the ventricles enter diastole, aortic valve closes & the walls of the aorta recoil (70-80mmHg), so the blood continues to flow forward into the smaller vessels

Question 23

Pulse Pressure

Answer 23

• The difference between diastolic and systolic prsssure
• The mean arterial pressure (MAP) represents the pressure that propels blood to the tissues, and is approximately diastolic pressure + 1/3 pulse pressure

Question 24

Capillary blood pressure

Answer 24

this is low, ranging from 15-40mmHg, which protects the capillaries from ruptures but is still adequate to ensure exchange between blood and tissues

Question 25

Venous blood pressure

Answer 25

This is low, not pulsatile, and changes every little during the cardiac cycle, reflecting cumulative effects of peripheral resistance

Question 26

Hypertension

Answer 26

• High blood pressure
• Characterized by a sustained increase in either systolic/diastolic pressure
• Primary hypertension: accounts for 90% of cases, and has no identifiable cause
• Secondary hypertension: 10% of cases, has a root cause by another thing and if that other thing (kidneys) is fixed, then the blood pressure is fixed

Question 27

Hypotension

Answer 27

• Low blood pressure
• Often due to individual variation. Only a concern if blood flow to tissues becomes inadequate

Question 28

Circulatory shock

Answer 28

• Any condition in which blood volume is inadequate and cannot circulate normally, resulting in blood flow that cannot meet the needs of a tissue

Question 29

Hypovolemic shock

Answer 29

• Results form a large scale loss of blood
• May be characterized by an elevated heart rate & intense vasoconstriction

Question 30

Types of circulatory shock

Answer 30

• Vascular shock
• Transient vascular shock
• Cariogenic shock

Question 31

Vascular shock

Answer 31

• Occurs with normal blood volume but extreme vasodilation, resulting in poor circulation and a rapid drop in blood pressure

Question 32

Transient vascular shock

Answer 32

• Due to prolonged exposure to heat, such as while sunbathing, resulting in vasodilation of cutaneous blood vessels

Question 33

Cardiogenic shock

Answer 33

• Occurs when the heart is too inefficient to sustain normal blood flow and is usually related to myocardial damage, such as repeated myocardial infarcts