The Circulatory System

Cardiovascular System Facts The average person has nearly 100,000 km of blood vessels running through them. The larger the organism, the slower the heart beats (a woman s heart will beat faster than a man s) A blue whale s heart beats 5 times per minute while a hummingbird s beats closer to 1400 times Blood in your veins is not blue! They look blue due to the way the light is absorbed and reflected in your skin. Your heart produces enough pressure to shoot blood nearly 30 feet.

The Heart The heart is the pump in our body which stimulates the movement of the blood. In an adult, it is about the size of a fist. It is located roughly in the middle of the chest between the lungs. It is composed of 4 chambers.

The Heart The four chambers of the heart are: Right atrium Right ventricle Left atrium Left ventricle

The Heart

The Heart The atrium and ventricle on the respective sides are directly linked The left and the right side have no direct link. They are separated by a partition, the septum. For the left and right side, blood flows into the heart through the atrium and is pushed out through the ventricle.

The Heart To prevent blood from flowing backwards in the heart, valves are present in the heart These valves are called the atrioventricular valves. Without these, blood would flow backwards through the heart.

The Heart There are 5 major blood vessels connected to the heart. Superior and inferior vena cava Pulmonary vein Pulmonary artery Aorta

The Heart

Function of the Heart The heart pumps blood to the entire body First phase of a heart beat is diastole The heart is at rest and the atriums fill with blood. Next the atriums contract, pushing blood into the ventricles. The final phase is when the ventricles contract, pushing blood out into the arteries. This phase is called systole.

The Heart

Blood Pressure When you take your blood pressure, you always get 2 numbers The systolic pressure it he higher number and indicate the pressure caused by the contraction of the heart The diastolic pressure is the pressure between beats. It is better to have lower blood pressure, within reason

Your Pulse When taking your pulse, the pulse you feel is the systole. An average heart beats around 75 times per minute. This number varies depending on age, gender, physical fitness and physical activity.

Types of circulation. The heart is a double pump. There are two circulatory routes which the blood takes. The right side is responsible for the pulmonary circulation. The left side is responsible for the systemic circulation.

Circulatory Routes

Pulmonary Circulation This circulation brings blood to and away from the lungs. Right side of the heart is responsible for this circulation. Blood is pushed out of the heart by the right ventricle through the pulmonary artery. The blood then passes through the capillaries and then returns to the heart through the pulmonary vein.

Systemic Circulation This is the circulation which sends blood out to the body systems (except the lungs). The blood is pushed out the of heart by the left ventricle through the aorta. The aorta splits and sends blood out through different parts of the body. The blood then gives its oxygen, nutrients and other goodies to the body tissues through the capillaries. The blood then returns to the heart through the veins.

Blood Vessels Now that we understand how the heart works and we know where the blood goes, let s talk about the pathways it takes. There are three types of blood vessels in our bodies. Arteries Veins Capillaries

Arteries Arteries are the largest blood vessels in our bodies They carry blood from the heart to other parts of the body. Their walls are very thick. This helps them withstand high pressures.

Arteries

Veins Veins carry blood back to the heart from the body systems. They are thinner than arteries. They also have small valves in them to prevent the blood from falling back down. The pressure is lower than in arteries.

Veins

Capillaries Capillaries are small vessels which are only 1 cell thin. This is the site of gas and nutrient exchange. They are the bridge between the veins and arteries. Where else have we seen capillaries?

Capillaries

Comparing Blood Vessels

Diseases of the Heart We are going to discuss 5 diseases of the heart and vessels. Arteriosclerosis Atherosclerosis Angina Heart attack Stroke

Arteriosclerosis This is a condition where the arteries thicken and become harder. This causes them to be less flexible. Less flexible means that it puts more pressure on the heart. This is caused by age, smoking, bad diet, drugs and a poor lifestyle There are currently no proven medical treatments for this condition as of yet.

Atherosclerosis This conditions is caused by a build up of plaque inside the arteries. These plaques are caused by too much fat and cholesterol in an individuals diet. Treatments are improved diet and exercise. There are some medications which can be taken, but exercise and diet at the first to be tried.

Atherosclerosis

Angina This is also referred to as angina pectoris. This is a sharp chest pain. This is caused by ischemia to the heart, which means a lack of oxygen to the heart. This is caused by a blockage of the coronary artery, meaning atherosclerosis of the arteries around the heart. Treatments include nitroglycerin, a strong vasodialator.

Angina Treatments include nitroglycerin, a strong vasodialator. A vasodilator is something which dilates, opens up, the blood vessels. This allows more blood and thus more oxygen through. Since the cause is blockages of the arteries, taking care of those blockages is the first priority. Again, diet and exercise!

Heart Attack This is also called a myocardial infarction. A heart attack is caused by a lack of oxygen to the heart. This causes part of the heart to die. The lack of oxygen is caused by a blockage in the coronary arteries (the vessels which feed the heart).

Heart Attack Symptoms of a heart attack are chest pain, numbness in either arms, nausea, shortness of breathe, etc. Nitroglycerin can be administered to help prevent further damage. Without needing to said, heart attacks can be quite deadly. The older you are when you have a heart attack, the more likely you are to survive.

Heart Attack

Stroke A stroke is caused by a blood vessel in the brain either bursting or becoming blocked. This can lead to loss of brain function, ability to move one or more limbs, loss of speech or many other past abilities. This is due to the lack of oxygen to the brain. The effects could be permanent or temporary and there is no way to know.

Stroke Risk factors for a stroke are old age, high blood pressure, diabetes, high cholesterol and smoking. In this case, the smoking can lead to arteriosclerosis which makes the vessels more prone to breaking. Prevention is the best defense against strokes. Once a patient is cleared of the danger of a stroke, the recovery is a long process.

Stroke

Circulatory System Facts The heart beats around 3 billion times in the averages person's life. About 8 million blood cells die in the human body every second, and the same number are born each second. It takes about 20 seconds for a red blood cell to circle the whole body. Red blood cells make approximately 250,000 round trips of the body. Red blood cells may live for about 4 months circulating throughout the body.

Blood Blood is composed of different constituents. It is also the only liquid tissue in the body. A man s body contains approximately 5-6 L of blood and a woman s contains 4-5 L. Although it seems like a homogeneous mixture, blood is a solution of components suspended in a liquid.

Blood after centrifugation

Plasma The liquid component of the blood. It is 90% water in which has substances dissolved into it such as: Hormones Nutrients Antibodies Waste It is used for transportations of substances.

Blood Plasma

Blood Constituents Red Blood Cells are red-coloured cells in the form of a biconcave disk. They have no nucleus and very few organelles. There are about 4-6 billion per ml They responsible for carrying oxygen through the use of hemoglobin.

Red Blood Cells

Blood Constituents White blood cells are transparent cells. There about 4-11 million per ml of blood. Their role in the body is for our immune system. They seek out and attack intruders in our bodies.

Types of White Blood Cells

Blood Constituents Platelets are irregular cell fragments. There are between 150-400 million per ml of blood. They help in blood clotting. With a low platelet count, one could bleed to death from a simple paper cut.

Platelets

Blood Types Humans have 4 different blood types. A B AB O The blood type is determined by surface proteins on the red blood cells. There is also one other substance on their surface The Rh factor

Rh Factor The Rh factor is known as the rhesus factor because it was first discovered on the red blood of rhesus monkeys, also known as macaques.

Surface Proteins There are proteins on the surface of the red blood cells. The red blood cells are what determine an individuals blood type. There are three different surface proteins A B Rh

Surface protein What s your blood type? Blood Type A+ A- B+ B- AB+ AB- O+ O- A X X X X B X X X X Rh X X X X

Blood Types in Quebec Distribution of types A, B, AB and O Distribition of Rh Positive and Rh Negative Rh Negati ve 15% O 46% A 42% AB 3% B 9% Rh Positi ve 85%

Distribution of the Eight Blood Types in Quebec Distribution of the Eight Blood Types AB+ 3% B+ 7% O- 7% B- 3% A- 6% AB- 1% O+ 39% A+ 36%

Blood Transfusions A blood transfusion entails the injection of blood into a person. A donor is defined as the person who gives blood for the purpose of a transfusion A recipient is a person who receives blood from a transfusion

Blood Transfusions Before the discovery of blood types in 1902, many transfusions resulted in the death of the recipient. We are well aware of the rules of blood transfusion. What do you think this rule is?

The Blood Rule Remember the surface proteins on the red blood cells. Those are the key to safe blood transfusions. To safely receive blood, you must not receive something you don t already have. You cannot receive something which you don t have!

Recipient Blood Compatibility Donor O- O+ A- A+ B- B+ AB- AB+ O- X O+ X X A- X X A+ X X X X B- X X B+ X X X X AB- X X X X AB+ X X X X X X X X

Blood Compatibility Remember, way for a blood transfusion to work safely the recipient must not receive something which they do not have. If you are blood type A-, you can t receive B or +. This means that O-, which is empty is the universal donor. AB+ is the universal recipient because it already has everything.