1.2 – The structure and functions of the cardio-vascular system Learning objectives To understand the functions of the circulatory system. To be able to identify the differences between veins, arteries and capillaries. To be able to identify and label the components of the heart. To describe the components of blood and the role they play in the body. To be able to define heart rate and describe the effect training has on resting heart rate.

Cardiovascular System - components This involves the HEART, BLOOD VESSELS & BLOOD. Photo by: © istock Photo Watch me Why is the circulatory system key to physical education?

2.Controlling body temperature. Functions of the Cardiovascular System 1.Transporting substances around the body. These include oxygen, glucose, carbon dioxide and waste products. 2.Controlling body temperature. 3.Protecting the body. Blood contains cells and anti-bodies that fight infection and stop bleeding(clotting) Photos by: © istock Photo

Types of blood vessels Once blood leaves the heart, it is transported around the body in three main types of blood vessels: Arteries Veins Capillaries Photos by: © istock Photo

Types of blood vessels Arteries transport the oxygenated blood away from the left side of the heart. The largest artery in the body, connected directly to the heart, is the Aorta Photo by: © deshow.net Arteries carry blood under a high pressure

Types of blood vessels Veins transport blood from all over the body back to the heart and lungs for re-oxygenation. They are blue because they carry blood that is full of waste products, and are low in oxygen. Photo by: © deshow.net Veins carry blood under a low pressure

Remember = Veins have Valves Types of blood vessels An unique feature of veins is that they have valves. Like the valves in the heart, they are there to prevent a backflow of blood. The blood must flow in one direction only, against gravity in most cases, back to the heart. Remember = Veins have Valves Photo by: © deshow.net

Arteries Veins Arteries and Veins What are the differences between arteries and veins? Arteries Take blood away from the heart Walls are thick and elastic Transports oxygenated blood Has small lumen Has a pulse and blood travels in spurts Has no valves Veins Take blood to the heart Walls are thin Transports de-oxygenated blood Has large lumen Has no pulse and blood travels smoothly Has valves

Types of blood vessels - capillaries Capillaries are small blood vessels that carries blood to and from the body’s cells. They are one cell thick and are exchange points where oxygen and carbon dioxide cross into the tissue cells (muscles) from the arterioles.  The capillaries at the lungs allow the cardio-vascular system to interact with the respiratory system – this is where oxygen and carbon dioxide are exchanged via the alveoli Photo by: © deshow.net

When you breathe in, they fill with air. Gaseous exchange at the alveoli Note: this is where the cardio-vascular system and the respiratory system over-lap Gaseous exchange takes places at the alveoli. The alveoli are tiny air sacks inside the lungs.  When you breathe in, they fill with air. The alveoli are covered in tiny capillaries (blood vessels). Gases can pass through the thin walls and travel into the blood stream. With training this process of gaseous exchange becomes more efficient and therefore improves performance. Photo by: © LOCOG

Cardiac muscle Structures of the cardiovascular system What type of muscle is the heart? Photo by: © istock Photo Cardiac muscle

Structures of the cardiovascular system RIGHT ATRIUM LEFT VENTRICLE RIGHT VENTRICLE LEFT ATRIUM Photo by: © istock Photo An upper chamber receiving de-oxygenated blood An upper chamber receiving oxygenated blood from the lungs A lower chamber containing oxygenated blood A lower chamber containing de-oxygenated

The 4 main blood vessels Aorta Oxygenated blood is pumped at high pressure from the heart to the body Pulmonary artery Carries deoxygenated blood from the heart to the lungs. Vena Cava Returns deoxygenated blood to the heart. Pulmonary vein Photo by: © istock Photo Returns oxygenated blood to the heart.

Other important structures of the cardiovascular system Septum Tricuspid valve Semi-lunar valves Bicuspid valve Photo by: © istock Photo Prevent blood flowing back into the left atrium. Prevent expelled blood flowing back into the heart. Prevent blood flowing back into the right atrium from the ventricle. The wall dividing the left and right sides of the heart.

The components of blood 1. Red blood cells carry oxygen from the lungs to the muscles + Removes CO2 from muscles to lungs. Contain a red-coloured compound called haemoglobin which bonds with oxygen to form oxyhaemoglobin Photo by: © Hank Grebe. http://mediaspin.com/blog/?paged=17 How do red blood cells help a sports performer? These cells are responsible for carry oxygen to working muscles. Without these cells performers would fatigue and stop.

The components of blood 2. White blood cells defend against disease. They are vital to health and preventing infection after injury. 3. Platelets and plasma clot the blood to stop bleeding. Platelets are important in healing injuries. Photo: © Stock.xchng.

Vascular Shunting During exercise, blood flow to muscles increases to meet the increase in oxygen demand. This redirection of blood flow to the areas where it is most needed is known as a vascular shunt.

Blood Redistribution The body uses two mechanisms to control this Vascular Shunting. Vasoconstriction (narrowing) and Vasodilation (expanding) is used to redistribute blood to essential areas of the body while decreasing blood flow to others. Think about the following: Where is the blood needed during exercise? Where is blood needed just after a meal? What will happen to blood vessels around the muscles?

Recall it! What has stuck with you? Cardio-Respiratory system Explain 2 functions of the cardiovascular system? Explain the purpose of arteries and veins in the body? Describe the terms vasoconstriction and vasodilation. What is the function of red blood cells, white blood cells and platlets?

Practice it! Exam questions 1. (i) Blood is circulated around the body. Name the type of blood vessel that returns blood to the heart. (1) ........................................................................................................ (ii) This type of blood vessel contains valves. What is the function of these valves? (1) ................................................................................................................................................................................................................ ..............................................................................................

Practice it! Exam questions 2. Blood is made up of different components. Complete the table below by identifying the: (6) (i) components; (ii) function of each component; (iii) importance to the sports performer. Component of blood Function of each component Importance to sports performer Oxygen delivery for activity White blood cells Stops blood loss so the performer can continue to play

Practice it! Marks Scheme: (i) Veins/vena cava/ pulmonary vein. (ii) Stop backflow of blood/stop blood going backwards/stop blood going the wrong way 2. Component of blood Function of each component Importance to sports performer Red blood cells Carry/ collect/ transport oxygen/O2 Fight disease/help immune system/ Keep the performer healthy so they can compete Platelets Aid clotting/form a scab