HUMAN TRANSPORT SYSTEM

Parts of the Circulatory System Blood Heart Blood vessels

BLOOD Is a liquid tissue (organelles, cell, tissue, organ) Your body contains 3 to 5 liters of blood 2 PARTS LIQUID – PLASMA- 90% water,also contains dissolved proteins,salts,sugar,vitamins,food, and wastes SOLID - cells

BLOOD FUNCTIONS OF BLOOD: Carries materials to the cells (nutrients, oxygen, hormones etc) Carries wastes away from the cells (carbon dioxide, nitrogenous wastes etc) Helps regulate body temperature Helps to protect against infections

Components of Blood RED BLOOD CELLS Are disc shaped and biconcave Contain hemoglobin (an iron containing protein) which carries oxygen and gives blood it’s red color Are produced in the bone marrow Lack a nucleus

Blood Components White Blood Cells Have a nucleus Protect the body from disease Produced in bone marrow, lymph nodes,spleen pus= many white blood cells at the site of an infection

Types of White Blood Cells

PLATELETS Small cell fragments Do not have a nucleus Help with the formation of blood clots (blood clotting is a series of enzyme controlled reactions) Heparin- substance produced by the liver that prevents blood from clotting in the blood vessels

BLOOD CELLS Can you identify the types of cells?

BLOOD VESSELS Arteries: Carry blood away from the heart Most carry oxygenated blood The walls are thick and elastic Smallest arteries are called arterioles Largest artery is the aorta

BLOOD VESSELS Veins Carry blood back to the heart Most carry deoxygenated blood Walls are thin and only slightly elastic Have valves to prevent the backflow of blood Smallest veins are called venules Largest veins are the inferior and superior vena cavas

BLOOD VESSELS Veins

BLOOD VESSELS Capillaries Connect arterioles to venules Exchange of materials between blood and cells takes place here (oxygen, nutrients, wastes) Are 1 cell layer thick (RBC’S pass 1 at a time)

Next notes on circulation pathways

Lymph When blood plasma diffuses through the walls of the capillaries and surrounds the cells it is called intracellular fluid or ICF, which helps move materials between the blood and cells. When ICF diffuses into lymph vessels it is called lymph