CVS Flashcards
Which vessels come off the arch of the aorta (right to left)?
Brachiocephalic, left common carotid, left subclavian.
(Alphabetical)
Note: right and left coronary Arteries come off the ascending aorta
How much blood is there is a normal man? And how much is stored in the veins?
6L in body
3.9 in veins
What are the 3 main types of arteries?
Elastic conducting - widest
Muscular distributing - most named arteries
Arterioles - narrowest
What is the tunica intima?
Inner layer of an artery containing an endothelium and subendothelium of connective tissue with internal elastic lamina.
Describe the structure of large arteries
TI
TM - 40- 70 fenestrated elastic membranes. Smooth muscle cells (create the fibres) and collagen bundles. May contain external elastic lamina.
TA
What is the tunic adventitia?
Outer layer of arteries.
Fibroelastic CT.
Often contains vasa vasorum, lymphatic vessels and nerve fibres. E.g. To stimulate vasoconstriction via diffusion of noradrenaline causing depolarisation of tunica media cells.
Describe the structure of muscular arteries
TI
TM: 40 layers of smooth muscle cells (connected via gap junctions) with a prominent external elastic lamina.
TA
What are end arteries?
Terminal artery supplying all or most of the blood to a body part - not branching with other arteries.
E.g. Coronary, splenic and renal
Describe the structure of Arterioles
TI - sometimes just endothelial cells TM - 1-3 layers of smooth muscle Internal elastic lamina only present in larger. No external elastic lamina. TA is scant.
Describe the structure of metarterioles
Supply blood to capillary beds.
Non continuous smooth muscle layer
Each muscle cell encircles the endothelium of the capillary functioning as a sphincter controlling blood flow at every branch entering a capillary bed.
Describe the general structure and function of capillaries and list the 3 types.
Largest surface area. Up only holds 5% of blood.
Single layer of endothelium and basement membrane.
Continuous capillaries, fenestrated capillaries, sinusoid/discontinuous capillaries.
Describe continuous capillaries.
Found in nervous, muscle, connective, exocrine gland and lung tissues.
Continual layer of epithelium with cells joined by tight occlusive joints.
Pericytes are found around them and are capable of becoming fibroblasts or muscle cells in wound healing.
Describe fenestrated capillaries and the 4 routes of diffusion.
Found in gut, endocrine glands and renal glomerulosus.
Windows in endothelium bridged by a thin diaphragm.
4 routes of diffusion:
Direct diffusion
Through fenestration
Through basement membrane
Through intercellular cleft
Describe sinusoid/ discontinuous capillaries
Found in spleen liver and none marrow.
Large diameter and slow blood flow.
Gaps exist allowing whole cells to move in and out of tissue and blood.
Describe postcapillary venules
Simple endothelium and Pericytes.
Low pressure so blood drains into them.
Compare corresponding veins and arteries.
Veins are bigger and have valves.
Arteries have bigger TM (I leg there is large TM to resist distension)
As veins get bigger TI and TA increases.
Veins contain less elastic fibres.
What are Venae comitants?
Veins wrapped around arteries.
Normally in pairs.
Pulsing of artery promotes Venus return.
What is the min and max blood flow to all tissues in the body?
5l.min-1 and 24.5
Describe the layers of the pericardium.
Fibrous pericardium
Serous pericardium: parietal pericardium (fused to fibrous) and visceral pericardium ( part of epicardium)
Where is the coronary sinus and great cardiac vein found?
Sinus: posterior of the heart, between left atrium and ventricle to the left of the inferior vena cava running to the left of the inferior left pulmonary vein. Great cardiac vein is the largest vein going into it on the left pulmonary vein side.
What are the rough muscular anterior walls of the atrium made of?
Pectinate muscles
What is the fossa ovalis?
Ruminant of the Foramen ovale on the interatrial septum.
What muscles line the interior of the ventricles?
Trabeculae carneae
What do chordae tendineae do?
Attach free free edges and the ventricle surfaces of the cusps of the tricuspid valve to the papillary muscles.
What are the papillary muscles?
Muscle projections of the ventricle wall which attach to chordae tendineae. This prevents the cusps prolapsing into the atria during ventricular systole.
How is the fibrous pericardial sac connected to the diaphragm?
It is continuous via the central tendon of the diaphragm
Describe the location of the right descending coronary artery
Posterior of the heart where the right artery splits, it is the descending artery.
Describe he location of the right marginal artery.
Main branch coming off the right artery on the anterior surface.