The Cardiovascular System

Function Transportation Blood = vehicle Transports oxygen, nutrients, cell wastes, hormones

The Heart Responsible for transporting all of those substances via circulation We actually have 2 circulatory systems: Pulmonary circulation Systemic circulation

Anatomy The heart is composed of many layers of tissue It is important that we keep them all straight so get ready!

Heart Coverings Enclosed by a double sac of serious membrane, the pericardium Visceral pericardium Hugs external surface of the heart Parietal pericardium Protects the heart and anchors it to surrounding structures Serous fluid in between to reduce friction created when the heart beats

Heart Muscle Heart walls are composed of three layers: Epicardium/visceral pericardium Myocardium Thick bundles of heart muscle Endocardium Lines the inside of the chambers

Picture! Let’s draw a picture putting it all together!

Circulation The heart is a double pump The right side is a pulmonary circuit pump Receives oxygen-poor blood from the veins of the body The left side is a systemic circuit pump Distributes oxygen- and nutrient-rich blood to all body organs

Heart Chambers The heart has 4 hollow chambers 2 atria 2 ventricles All are lined with endocardium In between is an interventricular septum Imagine your heart as a house The upstairs has 2 rooms called atria The downstairs has 2 rooms called ventricles

Review: Left vs Right B A

In between the atria and ventricles are valves These prevent the blood from going in the wrong direction Think of these as an escalator between two floors Escalators only go one way and transport blood from one place to the next!

Let’s draw a picture Left atrium Right atrium Interventricular septum Right ventricle Left ventricle

Tubes There are 4 sets of tubes in the heart One going from the body to the heart Called the vena cava There is a superior vena cava and an inferior vena cava The blood feeds into the right atrium Do you think this blood contains oxygen? NO!

There is another tube going from the heart to the lungs Why? The blood needs to get oxygenated This is called the pulmonary artery Connects the right ventricle to the lungs

Whiteboard review

Another tube brings the blood from the lungs to the heart Called the pulmonary vein Dumps blood into the left atrium Does the blood flowing through this tube contain oxygen? YES!

The Anatomy of the Heart The last tube connects the heart to the rest of the body Called the aorta The blood goes from the left ventricle, through the tube, and then to the rest of the body The coronary arteries that feed the heart branch off of this tube

Review What is the tube called that brings blood from the body to the heart? Vena cava What is the tube called that brings the blood from the heart to the lungs? Pulmonary artery What is the tube called that brings the blood from the lungs back to the heart? Pulmonary vein What is the tube called that brings the blood to the tissues from the heart? aorta

Clay!!! Clay=myocardium Straws=tubes

Let’s start at the beginning Imagine you are a blood cell in the tip of your pinky finger You have just finished delivering blood, oxygen, and nutrients to the cells there and now you are on your way back to the heart

You enter the heart via the inferior and superior vena cava and you are dumped into the right atrium

From the right atrium, you are dumped into the right ventricle after passing through the right atrioventricular valve

Valves: A sidenote The AV valves prevent the backflow of blood when the ventricles contract Consists of flaps of endocardium Tiny white cords called chordae tendinae anchor the cusps to the walls of the ventricles and control its opening and closing These are your “heart string”

Harry Potter Connection

Where were we? The blood cell goes from the right atrium, through the right atrioventricular valve, and then to the right ventricle

The right ventricle is very muscular and when contracted, it will squeeze the chamber, which will: Close the right AV valve Open the pulmonary semilunar valve Shuttle the blood through the valve and into the pulmonary artery

Break it down The pulmonary semilunar valve is just like any other valve Functions to prevent backflow of blood The pulmonary artery carries blood into the lungs Pulmonary MEANS lungs! Why does the blood need to visit the lungs?

Wait………Whuuuut? The pulmonary artery carries deoxygenated blood! Yes, you heard me right: The pulmonary artery carries deoxygenated blood! Write this down: Arteries carry blood Away from the heart Veins carry blood back to the heart

Question When our little blood cell was traveling on its way back from the heart, what type of vessel was it travelling in? A) vein B) artery VEIN!!!!

recap The blood cell is in the tip of the little finger Travels through a vein to a to the vena cava Dumps into the right atrium Passes through the right atrioventricular valve Dumps into the right ventricle Passes through the pulmonary semilunar valve in the pulmonary artery LUNGS We will add to this list later

In the lungs In the lungs, the red blood cell will obtain oxygen

After the RBC has picked up its oxygen, it is back to the heart! Enters through the pulmonary vein Remember: vein just means a vessel going TOWARDS the heart

The pulmonary vein dumps into the left atrium Predict Based on how things flowed on the right side, what is the RBC’s next stop? It will go through the left atrioventricular valve to the left ventricle

The left ventricle is very muscular in comparison to the right ventricle Why? Think about this: how far does the right ventricle have to pump blood? The lungs; that isn’t very far away How far does the left ventricle have to pump blood? A long ways! All the way to the tip of your pinky toe Against gravity to deliver blood to your head

The left ventricle contracts, it will: Close the right AV valve Open the aortic semilunar valve Shuttle the blood through the valve and into the aorta

Recap LUNGS Passes through the pulmonary vein on the way back to the heart. Dumps into the left atrium Passes through the left atrioventricular valve Dumps into the left ventricle Passes through the aortic semilunar valve in the aorta BODY!

Put it all together BODY Vena cava (superior or inferior) Right atrium Right atrioventricular valve Right ventricle Pulmonary semilunar valve Pulmonary artery LUNGS LUNGS Pulmonary vein Left atrium Left atrioventricular valve Left ventricle Aortic semilunar valve Aorta BODY

Put it all together with a picture

Put it all together with clay