Download Circulatory System

Circulatory System
Transportation system of the body
There are two types of circulatory systems:
1. Open Circulatory System ­ pumps blood to open ended vessels into the body cavities containing organs, then drains the cavity. e.g. insects
2. Closed Circulatory System ­ pumps blood through a series of closed vessels between the heart and the rest of the body organs.
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4 Functions of the Circulatory System
Pulmonary Circuit ­ (LUNGS) system of blood vessels that carries deoxygenated blood to lungs and oxygenated blood back to the heart
Systemic Circuit ­ (BODY) system of blood vessels that carries oxygenated blood to the body tissues and deoxygenated blood back to the heart
Systemic
2 Systems ("loops")
Pulmonary
1. Transportation of oxygen and carbon dioxide
2. Distribution of nutrients and transport of wastes
3. Maintenance of body temperature
4. Circulation of hormones
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Systemic System
body
cells
Pulmonary System
lungs
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Components of a Circulatory System
The Heart ­ a pump
• about the size of your fist
• located behind the lungs and slightly to the left
• covered by a sac of tissue, called the pericardium, that contains fluid that reduces friction
• the human heart has 4 chambers: 2 atria and two ventricles
• a wall called a septum separates the two halves of the heart that pump blood through the two loops. Valves control the flow of blood.
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The Blood ­ a fluid
Has 4 components:
Plasma: • the liquid part, makes up about 55% of blood and is 92% water
• is light yellow in colour
• contains sugars, minerals, wastes, amino acids, vitamins, salts and hormones
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Red Blood Cells (RBC)
• also called erythrocytes ­ you have about a trillion
• primary function is to carry oxygen throughout the body
• contain hemoglobin molecules that bind oxygen. Iron is a key component of hemoglobin and gives blood its red colour
• have a biconcave disc shape
• they do not have a nucleus
• average life span is 4 months
• produced in the bone marrow and stored in the spleen
• anemia results if a person is short on hemoglobin
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White Blood Cells (WBC)
• also called leukocytes
• they are an important part of the immune system (help defend body from disease and infection)
• there are 5 types based on size, shape and appearance
• they can sqeeze through the walls of capillaries and lymph vessels and wander (patrol) the body tissues
• pus sometimes forms at the site of a cut (or pimple!) and is a combination of WBC and dead bacteria
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Platelets
• are important to the clotting of blood
• much smaller than RBC and WBC
• surrounded by a membrane, but not considered cells
• the disease hemophilia results if a person's blood does not clot properly
• aspirin is a blood thinner since it prevents platelets from sticking together and forming a clot
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The Vessels
Tubes along which the blood travels
Criteria Artery Vein
Capillary
diagram
flexibility
direction of flow
valves?
thickness of walls
pressure
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Path of Blood
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Heart Sounds and Pressure
• the heart continually contracts and relaxes as a part of the cardiac cycle
• the relaxation portion is called diastole
• the contraction portion is called systole. During this time the ventricles contract pushing blood into the arteries.
• Pulse­ is the change in diameter of the arteries that can be felt on the body's surface following heart contractions
• Blood pressure ­ is the force of the blood on the walls of the arteries
­Measured with a sphygmomanometer
• Cardiac Output ­ is the amount of blood per beat (also known as the stroke volume) multiplied by the heart rate.
Example: What is the cardiac output if the stroke volume is 80ml/beat and the heart rate is 75 beats/min?
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More About the Human Heart
• the heart has its own supply of oxygen known as the coronary circulation, including the coronary arteries and its branches
• if a person has a sudden blockage in these arteries it is known as a heart attack
• heart disease is a slower process where these arteries are depriving the heart of oxygen. Some of the contributing factors include:
smoking, stress, lack of exercise and a high­
cholesterol diet
• a heart mumur is caused when one of the heart valves does not open or close properly
http://www.youtube.com/watch?v=0Vn5AJ_Mjfs
http://www.youtube.com/watch?v=rguztY8aqpk
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