Blood Vessels

Question 1

What are the layers of a blood vessel

Answer 1

Question 2

What does the lumen of blood vessels contain

Answer 2

Blood

Question 3

What does the tunica intima of blood vessels contain

Answer 3

Endothelial/Epithelial cells + basement membrane

Supporting connective tissue

Internal elastic lamina

(remember that this is the basic structure of like everything - epithelia, basement membrane, connective tissue)

Question 4

Epithelial cells of blood vessels

Answer 4

Simple squamous (like capillary; diffusion doesn’t really occur though so there are just more cells outside it)

Question 5

What does the tunica media contain

Answer 5

Smooth muscle (and elastin)

External elastic lamina

Question 6

What is the role of the tunica media

Answer 6

Like a thick wall around the vessel that stops the pressure and beating from being dissipated throughout the circulatory system

Question 7

Tunica Adventitia/Externa

Answer 7

Just a thick wall of supporting connective tissue around blood vessels

Question 8

Where do cells of the blood vessel get their oxygenation and nutrients from

Answer 8

Blood diffusing from the lumen, or from vasa vasorum in thick blood vessels

Question 9

Vasa vasorum

Answer 9

Blood vessels that supply blood to the outer cells in thick blood vessels

Vasculature of the vasculature

Think coronary arteris

Question 10

Structure and function differences between veins and arteries

Answer 10

Arteries have a larger tunica media to allow them to channel that pressurised pumping mechanism

Diameter of arterial lumen is smaller than that of the vein

Veins have generally thin walls and thick lumen**

Question 11

Elastic Arteries

Answer 11

Arteries near the heart that contain much more elastic tissue in the tunica media than muscular arteries, allowing them to maintain a mostly constant pressure despite the continuous beating of the heart

Question 12

Layers of the heart vessels

Answer 12

Endocardium (tunica intima); simple squamous epithelium, basement membrane, loose connective tissue

Myocardium (tunica media); cardiac muscle, suppolied by coronary vessels (vasa vasorum)

Epicardium (tunica adventitia/externa); Connective tissue bordered by simple squamous epithelium which forms the visceral pericardium

Question 13

Main difference in myocardium and tunica media

Answer 13

Myocardium is made of cardiac muscle while the tunica media is made of smooth muscle

Question 14

When are venous valves needed

Answer 14

Valves are generally not needed in the head and neck as the blood returns through gravity

It is generally needed in the limbs though to fight gravity

Question 15

How do valves and the muscle pump of veins work

Answer 15

Question 16

How does blood in vessels flow in the middle versus the edges and how does the surface of the endothelium facilitate this

Answer 16

It moves faster in the middle than it does on the edges - laminar flow

Non-stick surface of endothelium facilitates this

Question 17

Where can turbulent blood flow occur and what is its effects

Answer 17

Where blood vessels turn at a sharp angle and blood pressure is raised

It eventually damages the endothelium, exposing blood to collagen in connective tissue and other factors that clot blood

Question 18

Thrombus vs embolism

Answer 18

A thrombus is a blood clot that stays there while an embolism is a clot that travels

Question 19

Myocardial infarction

Answer 19

Heart muscle doesn’t get enough oxygen; heart attack

Usually caused by ischaemia of coronary arteries

Question 20

What are symptoms caused by hypertension

Answer 20

Damage to small and large blood vessels

• Atherosclerosis
• Arteriosclerosis
• Aortic dissection
• Abdominal aortic aneurysm

Damage to kidneys, CNS, heart, eyes

RCTs show BP reduction works to reduce stroke, MI, heart failure

10/5mmHg reduction in BP causes

• 40% less stroke
• 15% less CHD
• 21% less CV deaths
• 13% less Total mortality

Question 21

Atheroma and layers affected

Answer 21

Type of atheroclerosis - Thickening of walls in large and medium sized arteries

Occurs in high pressure systems (arterial not venous)

Initially disease of tunica intima, later affects media

Question 22

Describe the ubiquity of atheroma

Answer 22

Atheroma is ubiquitous, very mild in young people though and worsens with age

Question 23

Risk Factors for Atheroma

Answer 23

A - Arterial Hypertension
T - Tobacco
H - Hereditary
E - Endocrine (Diabetes, Hypothyroidism)
R - Reduced Physical Activity
O - Obesity
M - Male sex
A - Age

Question 24

Common sites of atheroma

Answer 24

Aorta, Coronary , Carotid, Cerebral, Renal, Iliac, Femoral and Popliteal Arteries, Major Intestinal Arteries

Question 25

Recognisable stages of Atheroma development (naked eye)

Answer 25

1. Fatty streak (Barely visible)
2. Lipid plaque (smooth, yellow, raised)
3. Fibrolipid plaque (hard, white)
4. Complicated Atheroma

Fats/Lipids, Fibre, ATHEROMA (BITCH)
idk this mneumonic works for me, don’t ask me to try explain it

Question 26

How do lipids enter the tunica intima in the case of an atheroma

Answer 26

Through a damaged endothelium

Question 27

What happens to form a fatty streak during atheroma development

Answer 27

High amounts of LDL cholesterol damages the endothelium and manages to slip into the cells and make a raised fatty streak

Macrophages try to phagocytose them but cannot break them down; thus they release cytokines causing inflammation and recruiting fibriblasts to build something around it (with collagen)

Question 28

How does a lipid plaque form during atheroma development

Answer 28

More and more macrophages trying to deal with more and more LDL-C; builds up and forms a bump

Fibroblasts lay down some collagen and harden the plaque; the LDL and plaque also begins to dig into the tunica media

Question 29

How does the fibrolipid plaque form during atheroma development

Answer 29

Collagen is laid down around it making a harder and bigger bulge/plaque which projects into the lumen and tunica media

Due to the T media projection, vessel loses elasticity as elastin and muscle is lost to collagen

Question 30

Complications of atheroma

Answer 30

• It can be so big that such little lumen is left and ischaemia occurs
• Wall is so weakened so a rupture is caused
• Thrombus is formed on top, further contributing to narrowing which can cause an embolism elsewhere

Question 31

3 Risk factors of thrombus formation

Answer 31

Stasis of blood flow
Endothelial Injury
Hypercoagulbility

Question 32

What are arterioles and venules

Answer 32

Smallest vessels in arterial/venous systems

Question 33

Role of arterioles during High BP

Answer 33

They constrict a bit and help reduce the impact of the high BP on cells

Question 34

Pathology of arterioles

Answer 34

If they have to continuously contract during hypertension, their muscles will thicken (hypertrophy)

Causes arteriolosclerosis

These become overtaken with collagen as this strengthens the walls, but they can then no longer effectively control blood flow through altering diameter

(Affects total peripheral resistence)

Question 35

Deep vein thrombosis

Answer 35

Pathology of veins

Starts with the stasis of blood at valves (especially lower limbs)

The clot begins to expand upwards then breaks off and travels around the system - gets stuck in lungs’ small capillaries causing pulmonary embolism

Question 36

How to detect DVT (deep vein thrombosis)

Answer 36

Ultrasound the veins and D-Dimer blood test (D-Dimer is a product of fibrin breakdown)