1. The Circulatory System

2. What is the circulatory system?
The circulatory system is a vast network of organs and vessels that are responsible for the flow of blood, nutrients, hormones, oxygen and other gases to and from cells.

3. What makes up the circulatory system?
Heart
Blood Vessels
The Blood
The Lungs (not going over this until later

4. The Heart The heart is the size of your fist.
The heart is located slightly to the left of the middle of your chest.
The heart is made up almost entirely of strong muscle tissue and is protected by your rib cage.
The heart contracts (tightens) and relaxes automatically about 70 times a minute to pump blood out through the arteries.
The heart has two sides separated by a muscle wall called the septum.
The right side of the heart is smaller and weaker and it pumps blood only to the lungs.
The stronger left side pumps blood around the body.
The heart consists of four hollow chambers: the right atrium, left atrium, right ventricle, and left ventricle.

6. Blood Vessels
Tubular structures which carry blood through the tissues and organs
Artery
Vein
Capillary

7. Arteries
Arteries are a tube-like blood vessel that CARRY BLOOD AWAY FROM THE HEART.
Arteries run alongside most of the veins that return blood to the heart.
The walls of arteries are muscular and can expand or relax to control the blood flow.
An arteriole is a smaller branch off an artery. Arterioles branch into microscopic capillaries.

8. The aorta is the main artery that carries blood away from your heart to the rest of your body.
After the blood leaves the heart through the aortic valve, it travels through the aorta, making a cane-shaped curve that connects with other major arteries to deliver oxygen-rich blood to the brain, muscles, and other cells.r cells.

9. Veins Veins are pipes in the body that carry blood BACK TO THE HEART.
The Superior Vena Cava and the Inferior Vena Cava
are the two largest veins in the body and bring the
blood flow into the heart from above and below.
Veins are pipes in the body that carry blood BACK TO THE HEART.
Unlike arteries, most veins carry ‘used’ blood back to the heart- the body cells have taken the oxygen they need from the blood, so it is low in oxygen.
When blood is low in oxygen, it is a dark, purplish blue color, unlike the bright red of the oxygenated blood carried by the arteries.
Inside most veins are flaps that act as valves to make sure that the blood only flows one way.

10. Heart Valves PULMONARY VALVE
Closes off the lower right chamber (or right ventricle).
Opens to allow blood to be pumped from the heart to the lungs (through the pulmonary artery) where it will receive oxygen.
Heart Valves
MITRAL VALVE
Closes off the upper left chamber (or left atrium) collecting the oxygen-rich blood coming in from the lungs.
Opens to allow blood to pass from the upper left side to the lower left side (or from the left atrium to the left ventricle).
AORTIC VALVE
Closes off the lower left chamber that holds the oxygen-rich blood before it is pumped out to the body.
Opens to allow blood to leave the heart (from the left ventricle to the aorta and on to the body).
TRICUSPID VALVE
Closes off the upper right chamber (or atrium) that holds blood coming in from the body.
Opens to allow blood to flow from the top right chamber to the lower right chamber (or from right atrium to right ventricle).
Prevents the back flow of blood from the ventricle to the atrium when blood is pumped out of the ventricle.

11. Capillaries
Capillaries are the smallest of the blood vessels and can only be seen under a microscope.
Capillaries link the arterioles to the venules.
It is through the capillary walls that your blood passes oxygen, food, and waste to and from each one of your body cells.
There are many more capillaries in active tissues such as muscles, the liver, and the kidneys than there are tendons and ligaments.

12. Blood
What is it?
Blood is the reddish liquid that circulates around your body.
What does it do?
Blood carries oxygen and food to body cells, and takes carbon dioxide and other waste away.
Blood fights infection, keeps you warm, and distributes chemicals that control body processes.
What is it made of?
Blood is made up of red cells, white cells, and platelets (tiny pieces of a cell that make blood clot to stop bleeding), all carried in a liquid called plasma (although it is 90% water, it contains hundreds of other substances including nutrients, hormones, and special proteins for fighting infection).
How much blood do we have?
The amount of blood depends on the size of the person, as well as their gender. As a general rule, adults have between 4 and 6 liters of blood (the bigger the person, the more blood) and males have more blood than females.

13. Understanding blood flow
Follow the numbers on the diagram to further understand…

14. What is heartbeat?
Heartbeat is the regular squeezing of the heart muscle to pump blood around the body.
It’s what makes the ‘lup-dup’ sound that the heart makes when it beats (can be heard through a stethoscope).
Heartbeat is usually measured simply by the counting the numbers of beats per minute (a.k.a. heart rate or pulse).
When you exercise, your heart speeds up so more blood can reach your muscles.

15. What is blood pressure?
Blood pressure is the force of your blood moving through your blood vessels.
Blood pressure is always recorded as two numbers, such as 120/80, where the top number is the systolic pressure and the bottom number is the diastolic pressure.
Systole pressure is when the heart muscle contracts (tightens) and pumps blood.
Diastole pressure is the pressure on the arteries when the heart is at rest in between heartbeats.

16. How the heart works…

17. Teaching groups and non-teaching groups…
ONE GROUP/ WEEK (yes, I changed it).
Non-teaching group members will be responsible for a separate assignment that focuses on the disease portion of the system.