The structure of the Heart and Major blood vessels

Question 1

What is the myocardial wall made up of

Answer 1

Three layers
the epicardium- outer layer which contains connective tissue and forms the inner membrane portion of the pericardium.
endocardium- inner most layer of the wall consists of a simple squamous epithelial layer overlaying a thinner areolar tissua
mid-myocardium- thickest portion of the hearts wall, the mid myocardium contains myocytes, nodal cells and purkunje fibres.

Question 2

Define semi lunar valves

Answer 2

aortic valves which separate the ventricles and the arteries.

Question 3

What is the purpose of the semi lunar valves

Answer 3

All valves open and close in response to pressure changes on weither side.

prevent the back flow of blood.

Question 4

What are atrioventricular valves

Answer 4

valves between the atriums and ventricles.
They are firmly attached to specialised tendons called chorine tendinae.

These are regualatory papillary muscles also contract.

prevent back flow of blood.

Question 5

What are the different types of blood vessels.

Answer 5

Arteries- carry blood away from the heart.

Arterioles- small vessels that carry blood from the arteries to capillaries. it helps maintain blood pressure

capillaries- microscopic vessels that connect arterioles to venues allows the control of blood distribution to organs.

venues- small vessels that drain blood from the capillaries into the vein

veins- carry blood from the venues to the heart and they help to maintain pressure and flow of blood.

Question 6

Define tunica interna

Answer 6

made up of
endothelial simple squamous cells single layer to facilitate diffusion.

basement membrane which separates the tunica interna from the tunica media.

Question 7

Define tunica media

Answer 7

Thickest coat with smooth muscle cells arranged in concentric circles.

contains gap junctions and elastin fibres.

Question 8

Define Tunica externa

Answer 8

collagen and elastin fibres.
consists mainly of longitudinal oriented collagen and elastin fibres.

contains vasa vasorum.

Question 9

What is released from the symapatheric nerve in the tunica external

Answer 9

Noradrenaline or norepinephrine

Question 10

What effects the resistance of blood vessels

Answer 10

Length of the vessel
Viscosity of the blood
Radius of the vessel