Cardiovascular system part 2 Blood Vessels

Human Cardiovascular System The human cardiovascular system is a closed system of blood vessels that transport many of your bodies needed nutrients and chemicals The blood is said to “make rounds” or go in a circuit through your body This idea is only about 3oo years old The human cardiovascular system is a closed system of blood vessels that transport many of your bodies needed nutrients and chemicals The blood is said to “make rounds” or go in a circuit through your body This idea is only about 3oo years old

The Pathways Blood will only flow in one direction but it has many pathways it can travel, similar how you have many different roads you can travel to go home from school The blood circulates through a series of tubes each with specific names and purposes: Arteries, arterioles, capillary beds, venules, and veins. Blood will only flow in one direction but it has many pathways it can travel, similar how you have many different roads you can travel to go home from school The blood circulates through a series of tubes each with specific names and purposes: Arteries, arterioles, capillary beds, venules, and veins.

The Path of Blood through the body

The order of pathways There is a specific order in which blood flows through out the body We start at the heart then go to the arteries into arterioles then capillaries From capillaries we go to venules, to veins, to the heart, to lungs, and back to the heart to get redistributed There is a specific order in which blood flows through out the body We start at the heart then go to the arteries into arterioles then capillaries From capillaries we go to venules, to veins, to the heart, to lungs, and back to the heart to get redistributed

Microscopic Anatomy of Vessels Most of the time when looking at vessels in the body magnification will need to be used The exception is when we look at large vessels as a whole Most of the time when looking at vessels in the body magnification will need to be used The exception is when we look at large vessels as a whole

Layers (Tunics) of blood vessels All vessels except for the microscopic capillaries have 3 coats that make up the wall Tunica Intima Tunica Media Tunica Externa All vessels except for the microscopic capillaries have 3 coats that make up the wall Tunica Intima Tunica Media Tunica Externa

Tunica Intima The Tunica Intima is the inner most layer of the vessel It is made of a thin layer of endothelium that rests on a layer of connective tissue It forms a slick surface to reduce friction for blood to flow through the vessel The Tunica Intima is the inner most layer of the vessel It is made of a thin layer of endothelium that rests on a layer of connective tissue It forms a slick surface to reduce friction for blood to flow through the vessel

Tunica Media Tunica Media is the bulky middle coat of the blood vessel It is mostly smooth muscle and elastic tissue This is the layer that is linked to the sympathetic nervous system that is the active player in changing the diameter of the vessel Tunica Media is the bulky middle coat of the blood vessel It is mostly smooth muscle and elastic tissue This is the layer that is linked to the sympathetic nervous system that is the active player in changing the diameter of the vessel

Tunica Externa Tunica Externa is the outer most layer Composed largely of fibrous connective tissue It is the support structure of the vessels Tunica Externa is the outer most layer Composed largely of fibrous connective tissue It is the support structure of the vessels