Blood Vessels

Question 0

Three Tunics of Artery and Vein Walls

Answer 0

(1) Tunica externa - loose connective tissue, lots of ANS nerve fibers, vaso vasorum
(2) Tunica media - smooth muscle, collagen, elastin - vasomotion
(3) Tunica interna - permeable layer consisting of endothelium (simple squamous epithelium)

Question 1

3 Types of Blood Vessels

Answer 1

(1) Arteries are efferent vessels, carrying blood away from the heart
(2) Veins are afferent vessels, carrying blood toward the heart
(3) Capillaries serve as the exchange vessels of the circulatory system

Question 2

Three Classes of Arteries

Answer 2

(1) Conducting (elastic or large) - largest class that contains elastic to withstand pressure “upstream” (ex aorta, common carotid, subclavian)
(2) Distributing (muscular or medium) - distribute blood to specific organs (ex brachial, femoral, renal, splenic)
(3) Resistance (small) - typically not given names - smallest are arterioles

Question 3

Metarterioles

Answer 3

Link arterioles and capillaries, contain precapillary sphincter that regulates blood flow

Question 4

Carotid Sinuses versus Carotid Bodies

Answer 4

• Carotid sinuses contain baroreceptors - increase in BP stimulates CN IX which delivers signals to the vasomotor and cardiac centers
• Carotid bodies contain chemoreceptors - change in chemistry stimulates CN IX and X to deliver signals to the respiratory center
• *there are also aortic bodies that perform similar functions**

Question 5

Three Types of Capillaries

Answer 5

(1) Continuous capillaries are found in skeletal muscle and allow for passage of small molecules
(2) Fenestrated capillaries are found in the kidneys, endocrine glands, small intestine, and choroid plexus of the brain
(3) Sinusoids (discontinuous) capillaries are found in the bone marrow, liver, and spleen

Question 6

Five Types of Veins

Answer 6

(1) Postcapillary venules
(2) Muscular venules
(3) Medium veins make up most named veins and contain venous valves
(4) Venous sinuses are thin veins not capable of vasomotion
(5) Large veins include the vena cavae, pulmonary veins, internal jugular veins, renal veins

Question 7

Three Portal Systems

Answer 7

Portal systems consist of two capillary networks before returning to the heart

(1) Glomerular-Pericapillary
(2) Hypothalamo-Hypophyseal
(3) Hepatic

Question 8

Types of Anastomoses

Answer 8

• Arteriovenous anastomoses drain from artery directly into veins
• Venous anastomoses drain vein-vein while arterial anastomoses drain artery-artery

Question 9

Korotkoff Sounds

Answer 9

• 1st sound is ~120 mmHg and represents systolic pressure

- 2nd sound is ~80 mmHg and represents diastolic pressure

Question 10

Pulse Pressure

Answer 10

Stress on small arteries

Systolic - Diastolic = pulse pressure

Question 11

Mean Arterial Pressure (MAP)

Answer 11

Diastolic + (1/3)Pulse pressure

Question 12

Three Factors of Blood Pressure

Answer 12

(1) Cardiac output
(2) Blood volume
(3) Peripheral resistance

Question 13

Factors of Peripheral Resistance

Answer 13

• Blood viscosity
• Length of vessel
• Vessel radius

Question 14

Three Ways of Controlling Vasomotion

Answer 14

(1) Autoregulation
(2) Neural control (baroflexes, chemoflexes, medullary ischemic reflexes)
(3) Hormonal control

Question 15

Hormones and BP

Answer 15

Angiotensin II, Aldosterone, ADH, Epi and norepinephrine raise BP

natriuretic peptides lower BP

Question 16

Three Causes of Edema

Answer 16

(1) Increased capillary filtration
(2) Reduced capillary reabsorption
(3) Obstructed lymphatic drainage

Question 17

Mechanisms of Venous Return

Answer 17

(1) Pressure gradient
(2) Thoracic pump
(3) Skeletal muscle pump
(4) Cardiac suction
(5) Gravity

Question 18

Circulatory Shock

Answer 18

State where cardiac output is insufficient to meet the body’s metabolic needs

Question 19

Two Categories of Circulatory Shock

Answer 19

(1) Cardiogenic shock - inadequate pumping by heart

(2) Low venous return (LVR) shock - CO low due to low return of blood
(a) Hypovolemic LVR shock results from dehydration, trauma, ulcers, etc
(b) Obstructed venous return shock results from tumor or aneurysm suppressing venous flow
(c) Venous pooling (neurogenic shock results from loss of vasomotor tone)
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Question 20

Septic Shock

Answer 20

bacterial toxins trigger vasodilation and increased capillary permeability

Question 21

Anaphylactic Shock

Answer 21

Results from exposure to an antigen a person is allergic to

Question 22

Transient Ischemic Attacks (TIAs)

Answer 22

Minor stroke with dizziness, weakness, aphasia

Question 23

Cerebrovascular Accident (CVA)

Answer 23

Stroke, sudden death (infarction) of tissue caused by ischemia