Histology (1)

Question 0

Where is blood flow at its fastest?

Answer 0

• Where cross-sectional area’s at its least

Question 1

Outline the route through vessels from the heart and back.

Answer 1

• Heart -> Large (elastic/conducting) arteries -> Medium (muscular/distributing) arteries -> Arterioles -> Metarterioles -> Capillaries -> Post capillary venules -> Venules -> Medium veins -> Large veins -> Heart

Question 2

Name the branches of the aortic arch.

Answer 2

• Brachiocephalic
• Left common carotid
• Left subclavian

Question 3

What is the major vessel that arises from the right ventricle and what does it split into?

Answer 3

• Pulmonary trunk

- Right and left pulmonary arteries

Question 4

Outline the initial route of the aorta and where it terminates.

Answer 4

• Posteriorly oblique arch descends into thoracic cavity

- Terminates by bifurcating into left and right common iliac arteries in the pelvis.

Question 5

What happens to the arteries during systole?

Answer 5

• Increase in blood pressure, so elastic arteries stretch.

Question 6

What happens to arteries during diastole?

Answer 6

• Aortic pressure decreases

- Walls of aorta recoils maintaining pressure on blood and moving it towards smaller vessels.

Question 7

What are the walls of arteries and veins from inner to outer?

Answer 7

• Tunica intima
• Tunica media
• Tunica adventitia

Question 8

What is the role of elastic arteries?

Answer 8

• Maintain blood pressure during diastole

- Stretch during systole

Question 9

What is the function of end arteries?

Answer 9

• Terminal artery supply all/most of the blood to a body part without collateral circulation
• So if occluded causes an insufficient blood supply to tissue

Question 10

What is the function of arterioles?

Answer 10

• Muscular arteries branch off to form arterioles

- Regulates the amount of blood reaching specific tissues/organs

Question 11

What is the function of metarterioles?

Answer 11

• Arteries supplying blood to capillaries (capillary beds)

- Contains precapillary sphincters to control blood flow into capillary bed.

Question 12

What is the role of capillaries?

Answer 12

• Blood supply to tissues

- Only 1 cell thick to allow shortest possible diffusion pathway

Question 13

What are the different types of capillaries?

Answer 13

• Continuous
• Fenestrated
• Sinusoids

Question 14

What are continuous capillaries and where are they found?

Answer 14

• Located in nervous, muscle and connective tissues
• Exocrine glands and lungs
• Continuous endothelial layer

Question 15

What are fenestrated capillaries and where are they found?

Answer 15

• Parts of gut, exocrine and renal glomerulus

- Interruptions exist across endothelium - bridged by diaphragm

Question 16

What are sinusoids and where are they found?

Answer 16

• Liver, spleen and bone marrow

- Gaps present in walls allowing whole cell exchange between blood and tissue

Question 17

What are post capillary venules?

Answer 17

• A more permeable version of capillaries
• Pressure is lower than in capillaries
• Fluid tends to drain into them.
• Unless inflammation - leukocytes and fluids emigrate

Question 18

What are venules?

Answer 18

• Merge of capillaries into venules

Question 19

What do veins arise from and what is their role?

Answer 19

• Venules
• Contains valves to prevent retrograde of blood
• Reservoir of blood, to be used when needed.

Question 20

What is the venae comitantes?

Answer 20

• Deep paired veins accompanying one side of the smaller arteries on each side of the artery
• 3 vessels wrapped together into one sheath.