Lecture 6- Circulatory system anatomy, Arteries and Veins

Question 1

What’s the first step in the supply path from the heart to the foot?

Answer 1

• Left side of heart into ascending Aorta. Aorta then arches up (aortic arch) and descends towards diaphragm (descending aorta).
• All of this is known as the thoracic aorta as in thoracic cavity.

Question 2

What happens in the supply path after the thoracic aorta?

Answer 2

Enters abdominal aorta

Question 3

In the supply pathway what happens to the abdominal aorta at the belly button?

Answer 3

At belly button the abdominal aorta splits into two to form the left and right common lilac arteries that go to the left and right lower limb

Question 4

In the supply pathway what happens after the branching to left and right common iliac arteries?

Answer 4

The Common iliac artery branches:

• External iliac artery go to lower limb (leaves abdominal cavity)
• Internal iliac artery supplies the bowl of the pelvis.

Question 5

In the supply path what happens when the are changes from the pelvic/abdominal area to the leg?

Answer 5

Have a name change the external iliac artery now becomes the femoral artery

Question 6

In the supply path what happens at the knee?

Answer 6

Behind knee (flexor aspect) is the popliteal artery

Question 7

What does the popliteal artery branch into?

Answer 7

Forms three major arteries, one is the posterior tibial artery. This sits at back of leg and goes to sole of foot to form a connection with plantar arches

Question 8

Put the arteries in order of the supply path from the heart to the foot:

posterior tibial artery
thoracic aorta
femoral artery
spilt into right and left common iliac arteries
left side of heart
connect with plantar arches at sole of foot
spilt into external iliac artery and internal iliac artery
abdominal aorta
popliteal artery

Answer 8

left side of heart
thoracic aorta
abdominal aorta
spilt into right and left common iliac arteries
spilt into external iliac artery and internal iliac artery
femoral artery
popliteal artery
posterior tibial artery
connect with plantar arches at sole of foot

Question 9

Put the veins in order of the deep drainage path from the foot back to the heart:

Popliteal vein
Inferior vena cava 
Right Atrium
External illiac vein
Posterior tibial vein
Femoral vein
Plantar venous arch
Common illiac vein

Answer 9

Plantar venous arch
Posterior tibial vein
Popliteal vein
Femoral vein
External illiac vein
Common illiac vein
Inferior vena cava 
Right Atrium

Question 10

What is the name of the vein that acts as superficial drainage? Where does it join with the deep drainage pathway?

Answer 10

Great Saphenous vein:

• Longest vein in the body
• Runs in the hypodermis (right below the skin)
• Goes deep and joins the femoral vein at the groin

Question 11

How many layers does the walls of blood vessels have and what are these called?

Answer 11

3 layers:

1. Tunica Intima
2. Tunica Media
3. Tunica Adventitia (Externa)

Question 12

What is the tunica intima made of?

Answer 12

-Endothelium: A simple squamous epithelium which
lines the lumen of all vessels.
-Sub-endothelium: A sparse pad of loose FCT.
cushioning the endothelium (provides support)
-Internal Elastic Lamina (IEL): a condensed (thin) sheet of elastic tissue.

Question 13

How does the internal elastic lamina compare between veins and arteries?

Answer 13

The IEL is well developed in arteries and less developed in veins

Question 14

Where is the internal elastin lamina located?

Answer 14

Boundary between intima and tunica media

Question 15

What is epithelium?

Answer 15

A class of cells epithelia cells (form boundaries), provide a non-stick function in blood preventing clotting

Question 16

What can be seen in a picture showing the histological structure of the artery?

Answer 16

• Very thin intima should be able to see the internal elastic lamina at boundary and small dots going into the lumen are the protruding nuclei of endothelium cells
• The tunica media will then be the thickest layer (stained pink). Smooth muscle cells will be in between the collagen and elastin fibers but we won’t be able to see them in a histological slide
• Then the Tunica Adventitia

Question 17

What is the tunica media made of?

Answer 17

-Smooth muscle
-A variable content of connective tissue fibers,
mainly elastin (rubber recoil) and collagen (tensile strength)
-Thickness of the media is proportional to both
vessel diameter and blood pressure.

Question 18

What will have a bigger tunica media: and artery or vein?

Answer 18

An artery will always have a thicker tunica media than a vein as it carried pressurized blood.

Question 19

What is the Tunica Adventitia made of?

Answer 19

• Loose FCT with a high content of collagen (tensile strength) and variable amount of elastin (recoil).
• In larger vessels, the adventitia contains the vasa vasorum.
• Lymphatics and autonomic nerves are also found in this region

Question 20

What is the vasa vasorum?

Answer 20

• Literally means the ‘vessels of the vessel’

- Blood vessels with thick walls need their own blood supply (they themselves are own organ system)

Question 21

What is the main function of the Tunica Adventitia?

Answer 21

It is the outer tensile sheath of the blood vessel stopping it from expanding any more (diameter limiting)

Question 22

How are the smooth muscle cells in the Tunica Media

orientated? What does this mean?

Answer 22

Circumferentially, means that when they shorten the vessel constricts and when lengthens it dilates

Question 23

Structurally what is the difference between a Thoracic Aorta and Femoral artery?

Answer 23

• Thoracic aorta is a elastic artery, meaning there are layers of elastin all throughout the tunica media. This means the tissue has a lot of recoil. Because there is so much elastin in the tunica media there is no need for any in the tunica adventitia
• Femoral arteries on the other hand are muscular arteries and so don’t have as much elastin

Question 24

What are arterioles?

Answer 24

Smallest arteries (last of supply network) before turning into capillaries

Question 25

What are Venioles?

Answer 25

Smallest veins (1st part of venous drainage system), come off capillary beds

Question 26

What is pulse pressure what is the trend in how it changes?

Answer 26

• Initially there is pressure pulses (contraction, relaxation). However, in capillaries the supply muscle we want a steady flow for exchange. The pulse effect is therefore dampened by taking up energy of the pulse into the elastic component of artery walls
• Pulse pressure therefore decreases as goes down

Question 27

What is the main function of arterioles?

Answer 27

The resistance vessels of the circulation - determine blood pressure.

Question 28

What is the basic function of capillaries?

Answer 28

Site of exchange between blood and tissues.

Question 29

What is a special feature of venioles? Why is it needed?

Answer 29

It is a low pressure drainage system and so valves ensure that the blood doesn’t go backwards/ in the wrong direction.

Question 30

What are the functions of veins?

Answer 30

• Low pressure, large volume transport system
• One-way (unidirectional) flow back to the heart
• Capacitance vessels= have spare capacity and so can hold extra blood volume

Question 31

What is the histological structure of veins like?

Answer 31

-Irregular, flattened shape with large lumen & thin
wall.
Three layers:
1. Intima- very thin
2. Media -Much thinner than arteries - a few layers of
smooth muscle (often in two distinct layers).
3. Adventitia -Often the thickest layer of a vein, lots of collagen prevents over distending/expanding.

Question 32

How do live veins compare to dead veins? Do arteries do this?

Answer 32

Live vein plump and round, dead collapses and crinkles (arteries don’t do this)

Question 33

What are Neves that run in the same tissue as arteries and veins called?

Answer 33

Neurovascular

Question 34

What do valves do in veins of the leg?

Answer 34

A contraction squeezes the vein and the action of a valve ensures that blood can only go up to the heart (not follow gravity down to feet)

Question 35

What causes varacus veins?

Answer 35

if vein dilates too much the valves no longer close/function properly resulting in baracus (visible veins). These are often elongated which results in the snake like appearance.

Question 36

What are the branches that exist from the aortic arch?

Answer 36

• Brachiocephalic trunk (goes towards right)
• Left common carotid artery (goes up to brain)
• Left subclavian artery (goes to left under collarbone)