Circulatory SystemBy Chris Durgham, Indrius Kveraga, Julian Volken

Functions of the Circulatory System

● Respiration - delivers oxygen to the cells and removing carbon dioxide from them

● Nutrition - carries digested food substances to the cells of the body● Waste Removal - disposes of waste products and poisons that would

harm the body ● Immunity - helps protect the body from disease● Cellular Communication - the circulatory system provides transport for

hormones● Thermoregulation - the circulatory system transports heat (can both warm

and cool body)

Structure of Blood Vessels

Arteries: are blood vessels that carry blood away from the heart. Arterioles: are small arteries, that connect larger arteries with capillaries. Small arterioles branch into collections of capillaries known as capillary beds.

Structure of Veins and Venules

Venules: Venules are smaller veins that gather blood from capillary beds into veins. Pressure in veins is low, so veins depend on nearby muscular contractions to move blood along.

Veins: Veins carry blood from capillaries to the heart. Veins have valves that prevent backflow of blood. The backflow makes sure that the blood reaches the heart.

Structure of Capillaries● Capillaries are one cell layer thick● Capillaries are concentrated into capillary beds.● Some capillaries have small pores between the cells of the capillary wall,

allowing materials to flow in and out of capillaries as well as the passage of whiteblood cells.

● Nutrients, wastes, and hormones are exchanged across capillaries.

● The blood vessels in which gas exchange occurs.

Gas exchange-Occurs in capillaries-Oxygen diffuses from the blood to the cells and carbon dioxide diffuses from cells into the capillaries-Gas molecules can diffuse only when dissolved in a liquid, which prevents it from occurring in non-optimal places as the capillaries’ layer of epithelium is wet at all times.

Gas Exchange Video

https://www.youtube.com/watch?v=XTMYSGXhJ4E&t=1m07s

The heart