THE CIRCULATORY SYSTEM
The Circulatory System is the transport system of the body. The functions of the Circulatory system are: It transports oxygen, nutrients and hormones to all parts of the body. It collects waste and carries it to the excretory organs, e.g. kidneys It defends the body against infection
The Circulatory System is made up of blood, blood vessels and the heart. Blood We need blood in our bodies to stay alive. Adults have about 5 liters or 9 pints of blood circulating inside their bodies, delivering oxygen and nutrients while removing wastes such as carbon dioxide from cells.
FUNCTIONS OF BLOOD Transportation Protection Temperature Regulation Maintaining body s equilibrium
THE BLOOD CONTAINS: Red blood Cells/ Hemoglobin-Transports oxygen and nutrients. White blood cells/ Leukocytes-These protect against foreign bodies that enter our bodies Plasma- A clear liquid, which makes up about 55% of blood. The liquid plasma carries the solid cells. Platelets- This helps the blood to clot. Without blood platelets, one would bleed to death.
BLOOD VESSELS Blood flows inside blood vessels on its journey to all parts of the body. Blood vessels in the body include: Arteries- carry blood away from the heart. Veins- carry blood back to the heart. Capillaries- the smallest blood vessels. Red blood cells inside the capillaries deliver oxygen and nutrients to body tissues as they remove carbon dioxide and other waste.
THE HEART The heart is the pump which circulates the blood to all parts of the body. The heart has four hollow chambers: The right atrium The right ventricle The left atrium The left ventricle. Blood flows into these before it is pumped to all parts of the body.
THE HEART CONT D In the heart there are also four valves which prevent the back flow of blood. Two are located between the atria and ventricles which are the tricuspid (right side) and bicuspid (left side) valves. The others are found between the heart and the arteries leaving the heart called the semi lunar valves The septum is a wall that runs down the middle of the heart dividing it into two parts. The walls of the heart is made up of cardiac muscle
Since the heart is divided down the middle each part is a pump, so the heart is double pump for double circulation. The right side pumps blood to the lungs and then returns it to the heart. This is known as pulmonary circulation. The left side pumps blood to the body and then it returns it to the heart. This is called systemic circulation
BLOOD CIRCULATION AROUND THE BODY
BLOOD CIRCULATION AROUND THE BODY. Deoxygenated blood enters the right atrium through the inferior and superior vena cava. The blood is pumped to the right ventricle. The right ventricle contracts and forces the blood through the pulmonary artery to the lungs. In the lungs, the blood becomes oxygenated and it flows back to the heart through the pulmonary vein to the left atrium. The blood, rich in oxygen is pumped to the left ventricle. The thick muscular wall of the left ventricle contracts and pumps the blood through the aorta to all parts of the body. The blood eventually returns to the heart and the cycle continues.
BLOOD CIRCULATION AROUND THE BODY.
THE CARDIAC CYCLE The average person s heart beats about 72 times per minute. Each heartbeat is a cardiac cycle which had three main stages. ATRIAL SYSTOLE- the contraction of the atria which pump blood in to the ventricles. VENTRICULAR SYSTOLE- the contraction of ventricles which pump blood to all parts of the body. COMPLETE CARDIAC DIASTOLE- the relaxation of the atria and ventricles allowing blood to enter the heart
PULSE Your heartbeat can be felt and counted via one s pulse in arteries just below the skin. The pulse is a person s heart rate which occurs when the left ventricle contracts and forces blood into the aorta. There are two places where a pulse is mainly checked. The radial artery found on the inside of the wrist The carotid artery found in the neck
BLOOD PRESSURE Blood pressure depends on how much blood flows into a blood vessel and how easily it can flow out. In terms of a person s blood pressure we refer to it as the measurement of blood pressure in the large artery found above the elbow. Blood pressure is measured in two ways Systolic Pressure - the measurement when the left ventricle of the heart contracts Diastolic Pressure the measurement when the left ventricle of the heart is relaxed
BLOOD PRESSURE Blood pressure is expressed as a fraction systolic pressure diastolic pressure Average blood pressure is 120/80 measured in millimetres of mercury
THE EFFECT OF THE CIRCULATORY SYSTEM ON OTHER SYSTEMS. The circulatory system is very important for the functioning of all the other systems of the body. All systems rely on it to supply them with oxygen and nutrients while removing waste such as carbon dioxide. If the Circulatory System stops functioning the other systems will also stop functioning and this can lead to death.
THE EFFECTS OF EXERCISE ON THE CIRCULATORY SYSTEM. Exercise can improve the Circulatory System in the following ways: The heart pumps more blood per beat.(stroke volume increases) The heart s recovery rate becomes quicker. The resting heart rate becomes lower. The number of capillaries in the body increases. Increase cardiac output. This means that the heart beats faster
THE END