Circulatory System Circulatory System The bodies transport system

Circulatory System

Circulatory System The bodies transport system: -Brings nutrients to the body cells (most can’t acquire nutrients on their own) - Transport waste to cells that are equipped to remove waste

Importance of the Circulatory System Single celled organism: All cells can get nutrients from the environment

Importance of the Circulatory Double celled membrane organism: Both sides get nutrients from the environment

Importance of the Circulatory Three or more celled membrane: Middle cells can’t get nutrients

Circulatory System How big is it? Number of cells in the human body: Number of km of blood vessels:

Circulatory System How big is it? Number of cells in the human body: - 60 trillion cells Number of km of blood vessels: - 96 000 km

Parts of the Circulatory System Types of blood vessels: • Arteries: • Arterioles • Capillaries: • Venules: • Veins:

Arteries Function of Arteries: Carry blood away from the heart Structure of Arteries: Layer Structure Outer layer Middle layer Inner layer Function

Arteries Function of Arteries: Carry blood away from the heart Structure of Arteries: Layer Outer layer Middle layer Structure Connective Tissue Inner layer Connective Tissue Elastic Connective Tissue Muscle Fibers Function

Arteries Function of Arteries: Carry blood away from the heart Structure of Arteries: Layer Outer layer Middle layer Structure Connective Tissue Function Prevents rupture from internal pressure Elastic Connective Tissue Allows artery to expand Muscle Fibers contract with the beat of the heart Inner layer Connective Tissue Prevents rupture of artery

Arteries and Pulse: The expanding of the arteries that occurs when there is a rush of blood into the artery (heart contracts)

Problems with Arteries Aneurysm: A condition where the inner wall of the artery is not strong enough to resist the pressure. Steps to rupturing the artery: 1) Inner layer starts to bulge

Anyeurysm 2) The bulge grows large enough to break through the other two layers

Aneurysm 3) The inner layer ruptures

Arterioles: Small versions of the artery (Same layers). Nerves and the Arterioles: The nerve controls the diameter of the arterioles Vasoconstriction: Sympathetic nerve impulse causes smooth muscles in arterioles to constrict Smaller diameter = low blood flow

Arterioles Vasodilation: When muscles relax and connective tissue springs the arteriole back to the normal diameter Larger diameter = higher blood flow

Problems in the arteries Atherosclerosis: Build up of plaque in the arteries Steps of Atherosclerosis: 1) Small droplets of fat deposit inside the artery 2) Other fat droplets are attracted to the first one 3) Minerals deposit on top of fat droplets making a fibrous net of plaque 4) Blood clots form around plaque