Lecture 20: Cardiovascular histology

Question 1

Endocardium

Answer 1

Innermost layer, lining atria and ventricles
Contains endothelium and subendothelial CT
Continuous with the tunica intima of the blood vessels entering and leaving the heart

Question 2

Subendocardium

Answer 2

Between endocardium and mycardium

Contains nerves and purkinje fibers

Question 3

Purkinje fibers

Answer 3

Carry impulses to ordinary cardiomyocytes

Question 4

Myocardium consists of

Answer 4

Consists of cardiac muscle cells

Question 5

Epicardium

Answer 5

External surface covered by simple squamous

Mesothelium overlies fibroelastic CT containing adipose cells, nerves and coronary vessels

Question 6

Cardiac skeleton

Answer 6

Dense collagenous CT

Myocardial fibers originate and insert onto the cardiac skeleton

Question 7

Tunica intima

Answer 7

Endothelium and basal lamina
-endothelial cells produce von Willebrands factor VIII
Subendothelial CT
Internal elastic membrane (incomplete in elastic, thick and complete in muscular arteries)

Question 8

Tunica media

Answer 8

Made up of circular smooth muscle tissue and fibroblasts

Contains collagen and elastic fibers

Question 9

Tunica adventitia

Answer 9

Outermost layer - lacking in arterioles
Consists of loose areolar CT
Contains irregular fibroelastic tissue with adipocytes
Has small vessels and nerves

Question 10

Elastic arteries

Answer 10

Conducting arteries
Stretch during systole and recoil during diastole
Tunica media consists of layers of elastic fibers
Includes- Aorta, pulmonary trunk, large branches of aorta

Question 11

Muscular arteries

Answer 11

Distributing arteries
Tunica media consists of smooth muscle that responds to autonomic stimulation
Includes- All named arteries of body except elastic arteries

Question 12

Arterioles

Answer 12

Tunica media consists of one-three layers of smooth muscle cells
Mean arterial pressure depends on proper tone of smooth muscle in arterioles
Give rise to metarterioles which have a discontinuous layer of smooth muscle tissue

Question 13

Continuous capillaries found where

Answer 13

Brain, muscle, thymus, bone, lung and other tissues

Question 14

Fenestrated capillaries found where

Answer 14

Tissues with substantial fluid transport-
Intestinal villi
Choroid plexus
Ciliary processes of eyes

Question 15

Discontinuous capillary fact and location

Answer 15

Basal lamina is discontinuous or absent

Question 16

Veins compared to arteries

Answer 16

Larger lumen
Thinner wall
Valves are present in many veins
Larger veins have a layer of longitudinal smooth muscle in the inner aspect of the tunica adventitia

Question 17

Prostacyclin

Answer 17

Prevents adhesion of platelets to endothelium, avoids blood clot formation
Also acts as vasodilator

Question 18

Review final few slides?

Answer 18

Good luck