Lecture 1 Flashcards
Functions of the circulatory system
Transport oxygen and nutrients to tissues
Transport carbon dioxide and waste products
Regulate body temperature
Transportation of substances
Organs of the blood vascular system
Heart, arteries, veins, and capillaries.
Layers of the circulatory system
Tunica intima, Tunica media and Tunica adventita
Tunica intima (heart)
(endocardium) thin layer, formed of simple squamous epithelium and is separated from media by elastic fibers
Tunica media (heart)
(myocardium) a muscular layer formed of cardiac muscle and is thick in ventricals
Tunica adventita (heart)
(epicardium) formed of mesothelium, collagen fibers and small vessels called Vasa vasorum.
The conducting system of the heart
Sino atrial node (S. A. N), atrioventricular node (A. V. N) and atrioventricular bundle (A. V. B)
Sizes of arteries
Large (elastic arteries)
Medium (muscular arteries)
Small arteries (arterioles)
Arterial system
Carry oxygenated blood from the heart to the capillaries
Structure of large arteries
Tunica intima: formed of simple squamous epithelium tissue called endothelium, and a layer of elastic fibers under.
Tunica media: formed of a thick smooth muscle layer with elastic fibers between it.
Tunica adventitia: formed of collagen fibers and small vessels called Vasa vasorum
Structure of medium artery
Tunica intima: formed from endothelium and is separated from Tunica media by the internal elastic layer.
Tunica media: a muscular layer of smooth muscle it’s thin and it’s separated from the adventita by the external elastic layer.
Tunica adventita: formed from collagen fibers and support the artery with surrounded structure.
Structure of small arteries
Tunica intima: a thin layer made of endothelium.
Tunica media: a layer of smooth muscle arranged into 6 layers.
Tunica adventita: a layer of collagen fibers and is fused with the surrounded structure.
(flow of blood is mainly maintained by these arteries)
Capillary
Thin walled vessel which exchanges materials between blood and the tissue.
The blood reaches the capillary through small arteries called prep capillary and leave it through small venules called post venules.
Structure of capillary
The walls are thin and formed of endothelium flat cells that rest on the basement membrane.
Small capillaries form most of the body capillaries while large capillaries (sinusoid) which is found in the liver, kidney and bone marrow.
Types of capillaries
Continuous capillaries
Fenestrated capillaries
Discontinuous capillaries
Continuous capillaries
No opening between the endothelium cells, this type forms most of the body’s capillaries
Fenestrated capillaries
Openings between the endothelium cells
Discontinuous capillaries
Has a discontinued basement membrane, it is found in the liver
Arteriovenouse shunt
An abnormal connection between arteries and veins which increases blood flow to the heart and speed up material exchange between the blood and tissue
Venous system
Carries deoxygenated bloodto the heart, the blood in the venous system moves by external pressure from muscle contractions, respiration and the valves found in the veins.
Small veins
Tunica intima: formed of endothelium
Tunica media: formed of two layers of smooth muscle (it’s very thin)
Tunica adventita: formed of collagen fibers connected with the surrounded structures.
Medium veins
It’s formed from a collection of small veins drained into the larger veins.
The structure of medium veins is the same of that of small veins but with a thicker tunic media and contains elastic fibers.
Large veins
Formed by the collection of medium veins. The structure is the same of that of medium veins but the Tunica media is thicker and contains collagen fibers and the internal elastic layer may be present.
