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Flashcards in The Circulatory System Deck (29)
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Overall, what does the circulatory system mediate?

The continuous movement of all body fluids


What are the four main functions of the circulatory system?

1. To transport oxygen and nutrients to tissues
2. To transport co2 and metabolic waste away from tis
3. Temperature regulation
4. Distribution of molecules and cells, e.g. hormones & immunocytes


What are the two functional components of the circulatory system?

1. The blood vascular system
2. The lymph vascular system


What is the blood flow initiated by?

The heart obviously


What is microcirculation?

Microcirculation refers to the smallest vessels in the body. The main sites of interchange between the tissues and the blood


Who was the first known to describe the systemic system and properties of blood in detail?

William Harvey


What are the three layers that the whole system has in common?

The tunica intima - the inner lining
The tunica media - intermediate
The tunica adventitia - outer supporting layer


What is the tunica intima?

The inner lining composed of flattened epithelial cells, endothelium, supported by a basement membrane and delicate collagenous tissue


What is the tunica media?

Intermediate mainly muscular layer. Shows the most variation out of all the layers


What is the tunica adventitia?

The outer supporting tissue layer


The tissues of thick walls of large vessels cannot sustain themselves by diffusion of nutrients from the lumina alone so what are they supplied by?

By the vasa vasorum - small arteries running in the tunica adventitia


The vasa vasorum are small arteries running in the tunica adventitia, where do they go from here?

They send arterioles and capillaries into the tunica media


The heart is made of the same three cell layers as the tissues in the

blood vessels


What are the three layers in the heart - both names?

1. tunica intima - endocardium
2. tunica media - myocardium
3. tunica adventitia - epicardium or visceral pericardium


What are papillary muscles?

A small muscle within the heart that anchors the heart valves


Where are the purkinje fibres found, in which layer?

In the subendocardial layer - run immediately below the endocardium


What is the function of the purkinje fibres?

To transmit electrical impulses in a co-ordinated manner


Describe the structure of the cells making up the endocardium

A surface layer of flattened endothelial cells


What is one of the functions of the endocardium?

Controls myocardial function


Describe the structure of the epicardium

A dense sheet of fibro-collagenous and elastic tissue


What is one of the functions of the mesothelial cells that make up the epicardium?

On the outer surface a single layer of flat mesothelial cells (simple squamous epithelium) are responsible for secreting lubricating fluid


What fibres make up the mycocardium?

Cardiac muscle fibres


What joins together different cardiac muscle cells?

Intercalated discs


Cardiac muscles have ____ nuclei and regular cytoplasmic _______

central and striations


What are purkinje fibres?

Modified cardiac muscle fibres involved in the regulation of co-ordinated contraction of the heart


Where do the purkinje fibres first begin?

About halfway down the interventricular septum


The heart valves consist of leaflets of...

fibroelastic tissue covered by endothelium on both sides


What is the function of the arterial system?

To distribute blood from the heart to capillary beds throughout the body


The cyclical pumping action of the heart ventricles produces a...

Pulsatile flow in the arterial system