Blood Vessels

Question 1

What are the great vessels?

Answer 1

Vena cava (superior and inferior)

Pulmonary arteries / pulmonary trunk

Pulmonary veins

Ascending aorta / arch of aorta

Question 2

Briefly describe superior and inferior vena cava

Answer 2

Superior vena cava is formed by the union of the right and left brachiocephalic veins

Inferior vena cava is formed by the union of the right and left common iliac veins (at level of L5)

Both drain into the right atrium

Question 3

Briefly describe the pulmonary trunk

Answer 3

continuation of the right ventricle via pulmonary valve, carrying deoxygenated blood to the lungs

divides into left and right pulmonary veins at level of sternal angle

Question 4

Briefly describe the ascending aorta

Answer 4

arises from aortic orifice of left atrium via aortic valve

first branches are left and right coronary arteries (from left and right aortic sinuses superior to aortic valve) which supply the heart

ascends 5cm to the level of the sternal angle where it becomes the arch of the aorta

Question 5

briefly describe the arch of the aorta

Answer 5

continuation of the ascending aorta at the level of the sternal angle

continues inferiorly as the thoracic and then abdominal laorta

gives off:

• brachiocephalic trunk
• left subclavian artery
• left common carotid artery

Question 6

What are the 6 types of blood vessels?

Answer 6

Arteries:

• elastic
• muscular / distributing
• arteriole / resistance

Veins:

• veins
• venules
• capillaries

Question 7

What are the three layers of blood vessel walls and what are they made up of?

Answer 7

Tunica intima

• internal
• endothelium (epithelial cells)

Tunica media

• middle
• smooth mm & elastic fibres

Tunica externa / adventitia

• external
• connective tissue & collagen

Question 8

What are the functions of the three layers of the blood vessel walls?

Answer 8

Tunica intima

• in direct contact with bloodstream
• nutrient & waste exchange in capillaries

Tunica media

• smooth mm contracts in vasoconstriction & to move blood through vessels (especially arteries)
• elastin provides stretch & recoil

Tunica externa

• collagen gives ability to stretch
• contains vaso vasorum & vaso navorum

Question 9

Which vessels only have one wall layer?

Answer 9

Capillaries - tunica intima only

Question 10

In which vessels are specific layers of the wall thicker and in which are they thinner?

Answer 10

Tunica intima
- similar in all

Tunica media

• thickest in arteries
• thinner in veins

Tunica externa
- thickest in muscular arteries and large veins

Question 11

What are the functions of each of the 3 types of arteries?

Answer 11

Elastic

• largest arteries near the heart
• elastin in walls allows large degree of stretch and recoil
• dampen pulsatile pressure by absorbing systolic pressure from heart

Muscular
- distribute blood flow to body tissues

Arteriole

• distribute blood into or bypass capillary beds
• active in vasoconstriction & BP regulation
• pre-capillary arterioles vasodilates in inflammatory response to allow more blood flow to injured tissue

Question 12

What are the functions of each of the 3 types of veins?

Answer 12

Capillaries

• arranged in interweaving networks called capillary beds
• exchange of materials between blood and interstitial fluid

Venules
- post capillary venules enhance inflammatory response via vascular permeability

Veins

• can accomodate a large blood volume (65% of total BV)
• convey blood back to heart via venous pumps

Question 13

What are the 4 mechanisms that aid venous return?

Answer 13

Valves
- avoid backflow of blood

Muscular pump
- contraction and relaxation of skeletal mm around veins pumps blood towards heart

Respiratory pump (w/ inspiration)

• decreased thoracic pressure ‘vacuums’ blood towarads heart
• increased intrabdominal pressure ‘pushes’ blood towards heart

SNS stimulation
- vasoconstriction can aid venous return

Question 14

What are the 7 major arteries supplying the heart?

Answer 14

Right Coronary:
- originates from arch of aorta above right coronary sinus
- travels down right coronary sulcus towards crux of heart
- supplies right atrium & right ventricle
Branches: right marginal & posterior descending

Right marginal:

• branch of right coronary at acute right margin of heart, and courses along acute margin of right ventricle towards the apex of the heart
• supplies right atrium and right ventricle

Right posterior descending:

• also called right interventricular
• branch of right coronary
• runs in posterior interventricular sulcus towards apex of heart (where it meets left anterior descending artery)

Left Coronary Artery:

• arises from arch of aorta above left coronary sinus
• divides into left anterior descending and left circumflex arteries

Left Anterior Descending:

• arises from left coronary
• descends in anterior interventricular groove
• connects with right posterior descending artery at apex of heart

Left Circumflex:

• arises from left coronary
• curves to the left and around to the posterior surface of the heart in the atrioventricular sulcus
• supplies most of the left atrium and posterior wall of left ventricle
• gives rise to left marginal artery

Left Marginal:
- branch / es off the left circumflex artery

Question 15

Which coronary arteries arise from the right and which from the left coronary artery?

Answer 15

Right Coronary:

• right marginal
• right posterior descending (right interventricular)

Left Coronary:

• left anterior descending
• left circumflex
• left marginal

Question 16

What are the 6 major veins of the heart?

Answer 16

Coronary sinus:

• runs from left to right along posterior atrioventricular sulcus
• all cardiac veins drain into coronary sinus
• drains directly into right atrium

Small cardiac vein:
- anterior right surface

Great cardiac vein:
- anterior left surface

Middle cardiac vein:
- posterior surface (right)

Left posterior ventricular vein
- posterior surface (left)

Left marginal vein
- posterior surface (left)