The circulatory system Your body’s “internal transport system”!

What the Circulatory system does: The heart moves blood through blood vessels. Vessels move blood through the body to carry: Oxygen Carbon dioxide Nutrients

What is blood made of? 55% = plasma a clear liquid made up of 92% water 8 % is salts, nutrients, proteins and other chemicals The rest of the blood = 3 kinds of blood cells Red = carry oxygen to the body White = protect the body from disease Platelets = cell fragments that cause blood to clot

Hemoglobin = oxygen-carrying pigment in red blood cells What color is blood??? Hemoglobin = oxygen-carrying pigment in red blood cells Is bright red when attached to oxygen Is dark red when doesn’t have oxygen Veins appear blue b/c different colors of light reach different depths in the skin = the blue light is reflected back by the veins

How does the heart work? Beats constantly (no rest!) It pushes blood through the vessels Blood carrying carbon dioxide returns from the body and enters the right atrium of heart Atrium = a chamber of the heart that RECEIVES blood Blood is pushed to the ventricle = pushes blood OUT of the heart toward the lungs and other parts of the body

What makes the heart beat? Contraction of the heart! 1. Signals at the top of the heart cause the heartbeat… 2. A group of cells called the “cardiac pacemaker” or S-A node start a signal… 3. The signal causes the atria to contract… 4. The signal is passed to cells in the a-v node and along to ventricles… 5. Ventricles contract… Yeah= you have a heartbeat!

TYPES OF BLOOD VESSELS: Arteries= Blood vessels that carry blood AWAY from the heart Capillaries= Tiny blood vessels that connect arteries to veins Veins= Blood vessels that carry blood FROM all parts of body BACK to the heart