Histology of Arteries + Arterioles

How many layers of capillary wall are there?

• 5

• 3

• 1

• 2

What are the main layers of the blood vessel wall?

• Tunica Medulla

• Tunica Intima: Endothelium

• Tunica Media: Smooth Muscle

• Tunica Externa

What are the additional components of blood vessels?

• Elastic Lamina

• Vasa Vasorum

• Nervi vasorum

• Basement membrane

What is the Tunica Intima?

• Layer that surrounds the glomerulus of kidneys

• The outer covering of a blood vessel

• The innermost lining of the blood vessel, in direct contact with blood

• A muscular and connective tissue layer

What is the Tunica Media?

• Layer that surrounds the glomerulus of kidneys

• The outer covering of a blood vessel

• The innermost lining of the blood vessel, in direct contact with blood

• A muscular and connective tissue layer that shows greater variation between vessel types

What is the Tunica Externa?

• Layer that surrounds the glomerulus of kidneys

• The outer covering of a blood vessel

• The innermost lining of the blood vessel, in direct contact with blood

• A muscular and connective tissue layer

Components of the Tunica Intima

• Endothelium

• Internal Elastic Lamina

• Basement membrane

• External Elastic Lamina

Answer explanation

Endothelium:

- innermost layer of tunica intima

- Thin layer of flattened cells

- Functions: Influence blood flow, secretes chemical mediators for smooth muscle contraction, allows for efficient blood flow by reducing surface friction

Basement membrane:

- a framework of collagen fibres that allow for tensile strength and acts a a mesh

- Plays an important role in guiding cell movements during tissue repair of blood vessel walls

- Provides resilience for stretch and recoil

Internal Elastic Lamina:

- Thin sheet of elastic fibres with openings that facilitates diffusion between Tunica Intima and tunica media

Components of Tunica Media

• Internal Elastic Lamina (Connective Tissue)

• External Elastic Lamina (Connective Tissue)

• Smooth muscle

• Basement Membrane

Answer explanation

Smooth Muscle:

- Huge role in controlling lumen diameter and regulating blood pressure

- Contracts when there is vessel damage to reduce blood flow

Components of Tunica Externa

• Vasa Vasorum

• Nervi Vasorum

• Endothelium

• Elastic lamina

What things do arteries have that veins do not have?

• Vasa Vasorum

• Smooth muscle

• Elastic Lamina

• Valves