106: Cardiovascular Histology

Question 1

What kind of blood vessel is this?

Answer 1

Elastic artery

• Thick tunica media with alternating layers of smooth muscle and fenestrated elastic lamellae

Question 2

What are the defining characteristics of muscular arteries?

Answer 2

• Tunica intima
  
  • Thin, prominent internal elastic membrane
• Tunica media
  
  • Prominent smooth muscle layer
  • Some elastic lamellae is present, but it does not alternate with smooth muscle
• Tunica adventitia
  
  • External elastic membrane at the interface with the tunica media

Question 3

What are the defining characteristics of elastic arteries?

Answer 3

• Thick tunica media
  
  • Alternating layers of smooth muscle and fenestrated elastic lamellae
  • This allows for stretch to accomodate large volumes of blood

Question 4

Where in the body are continuous capillaries found?

Answer 4

Nervous system (blood brain barrier)

Muscle

Fat

Question 5

What are the major general differences between veins and arteries?

Answer 5

• Veins have larger lumens
• Arteries have thicker walls

Question 6

Where in the body are fenestrated capillaries found?

Answer 6

Where extensive passage of fluid and metaboilites is required

• Endocrine organs
• GI tract
• Galbladder
• Kidney

Question 7

What is the function of arterioles?

Answer 7

Control blood flow into capillary beds to protect them from high pressure

Question 8

What kind of blood vessel is this?

Answer 8

Discontinuous/sinusoid capillary

• Gaps between cells and basement membrane

Found in liver, spleen, and bone marrow

Question 9

What are the 3 basic layers of the cardiovascular system?

Answer 9

• Tunica intima
  
  • Closest to lumen
  • Endothelium
    
    • Simple squamous everywhere except heart
    • Stratified squamous in the heart
  • Thin layer of connective tissue
• Tunica media
  
  • Thickest middle layer
  • Made from smooth muscle
• Tunica adventitia
  
  • Outer layer of connective tissue
  • Blends with the surrounding tissue

Question 10

What kind of blood vessel is arrow #5 pointing to?

Answer 10

Venule

• Single layer of smooth muscle

Question 11

What is the function of muscular arteries?

Answer 11

Maintain blood pressure

Question 12

What kind of blood vessel is this?

Answer 12

Muscular artery

• Smooth muscle tunica media with no alternating elastic laminae

Question 13

What kind of blood vessel is this?

Answer 13

Large vein (superior or inverior vena cava)

• Thick tunica adventitia with bundles of longitudinal muscle

Question 14

What kind of blood vessel is this?

Answer 14

Fenesrated capillary

• Tight junctions between cells
• Continuous basement membrane
• Pores in the tunica intima

Question 15

What kind of blood vessel is arrow #6 pointing to?

Answer 15

Arteriole

• 2 layers of smooth muscle

Question 16

Where in the body are discontinuous capillaries found?

Answer 16

Liver

Spleen

Bone marrow

Question 17

What kind of blood vessel is this?

Answer 17

Continuous capillary

• Tight junctions
• Continuous basement membrane

Question 18

What is a pericyte?

Where is it found?

Answer 18

Multi-functional cell with various properties

• Stem cell
• Contracticle
• Role in vascular network formation

Found in the basement membrane adjacent to endothelial cells

Question 19

Where in the circulation is most of our blood found at any given time?

Answer 19

Veins

Question 20

What kind of blood vessel is this?

Answer 20

Small or medium vein

• Thin intima and media
• Some bundles of longitudinal muscle in adventitia, at interface with media