Blood Vessels and Circulation

Introduction

Blood vessels

Veins and arteries consist of 3 distinct layers:

1. Tunica Intera (Inner layer) – Consist of endothelial lining, connective tissue and elastic fiber

2. Tunica Media (middle layer) – Commonly the thickest layer, contain smooth muscle tissue sheets, separated from externa by thin band of elastic membrane, smooth muscle cells encircle the endothelium lining,

3. Tunica externa (outer layer) – form a connective tissue sheath around vessel, In arteries contain callogen fibers with scattered bands of elastic fibers, in vein it is thicker then tunica media and contain elastic fibers and smooth muscle

Layered walls give them strength
Elasticity permits changes in vessel diameter

Arteries

Types of Arteries

1) Elastic Arteries: e.g.Pulmonary, common carotid, subclavian and common Iliac.

2) Muscular Artery e.g medium size arteries or distribution arteries

3) Arterioles

Capillaries

Continues Capillaries:

Fenestrated capillaries

Sinusoids

Capillary Bed

Vasomotion

Veins

Venules:


Medium sized veins:

Large Veins:

Venous Valves

Blood distribution

Cardiovascular circulation

Pressure

Resistance

Arterial Blood pressure

MAP = Diastolic pressure + Puls Pressure/3

Capillary exchange

Continues movement of water out of capillary and back to bloodstream by lymphatic system enables:

Shock

Symptoms: