Bbc bitesize cardiovascular system

The heart is working hard to pump blood around the body. Well, the blood has to be kept moving around all the time because it's the body's delivery system.

The first number is the systolic value and the second number is the diastolic value. Blood pressure is determined by Q cardiac output and the resistance to the blood flow R. Resistance to blood flow is caused both by the diameter of the blood vessels and by the thickness of the blood. Furthermore, if a person has a condition called atherosclerosis plaque in the arteries , their resistance to blood flow will increase and so will blood pressure. This can have serious health implications such as causing chronic high blood pressure, angina or even heart attack or stroke.

Bbc bitesize cardiovascular system

In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation close vasodilation The increase in diameter of the skin arterioles to increase blood flow and increase heat loss by radiation. This allows more heat to be lost from the blood. When a person takes part in exercise their face can become pink due to vasodilation of the blood vessels close to the skin's surface. In the cold, blood vessels at the skin's surface close. This process is called vasoconstriction close vasoconstriction The narrowing of the skin arterioles to reduce blood flow and reduce heat loss by radiation. Systolic is when the heart contracts and diastolic is when the heart relaxes. The first number is the systolic value and the second number is the diastolic value. Blood pressure is determined by Q cardiac output and the resistance to the blood flow R. Resistance to blood flow is caused both by the diameter of the blood vessels and by the thickness of the blood.

The atria collect blood and then pump them to the ventricles below.

In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation close vasodilation The increase in diameter of the skin arterioles to increase blood flow and increase heat loss by radiation. This allows more heat to be lost from the blood. When a person takes part in exercise their face can become pink due to vasodilation of the blood vessels close to the skin's surface. In the cold, blood vessels at the skin's surface close. This process is called vasoconstriction close vasoconstriction The narrowing of the skin arterioles to reduce blood flow and reduce heat loss by radiation. The first number is the systolic value and the second number is the diastolic value.

Heart rate is measured in beats per minute bpm. During exercise the heart rate increases so that sufficient blood is taken to the working muscles to provide them with enough nutrients and oxygen. An increase in heart rate also allows for waste products to be removed. Stroke volume increases which means more blood is pumped out of the heart each time it contracts. At rest a person's cardiac output is approximately 5 litres per minute, while during exercise it can increase to as much as 30 litres per minute as both their heart rate and stroke volume increase. Work out the cardiac output of a person at rest with a heart rate of 70 bpm and a stroke volume of 80 ml.

Bbc bitesize cardiovascular system

The heart is working hard to pump blood around the body. Well, the blood has to be kept moving around all the time because it's the body's delivery system. Every possible part of the body has to be supplied with oxygen and food and water, and the veins and arteries are like roads going all the way through your body with the blood cells like delivery vans.

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The main functions of the cardiovascular system. Key points. Structure of the cardiovascular system Structure of blood and blood vessels The main functions of the cardiovascular system Cardiovascular system and exercise. Plasma which is a yellowy liquid that carries these cells and important nutrients around your body. The heart's function is to pump the blood and circulate it round the body. The heart's performance as a pump. Blood is carried through three different types of blood vessels in the body:. The pathway of blood through the heart. Personalise your Bitesize! What is the digestive system? More guides on this topic. The average number of beats is 72 beats per minute. This process is called vasoconstriction close vasoconstriction The narrowing of the skin arterioles to reduce blood flow and reduce heat loss by radiation. Structure of blood and blood vessels. Personalise your Bitesize!

Blood transports materials and heat around the body and helps to protect against disease. It contains:. You have about 5.

Personalise your Bitesize! Require immediate backup! This is often called a 'figure of eight system'. In the heat, blood vessels close to the surface of the skin enlarge. Blood is made up of four components:. The heart has four chambers and a thick muscular wall. These are small blood vessels that branch off the aorta and can be seen on the external surface of the heart. The bicuspid valve separates the left atrium and left ventricle and prevents back flow of blood from the ventricle to the atrium. The 'figure of eight' human circulatory system. Activity 1: Fill in the gaps. This is called cardiac output. The average number of beats is 72 beats per minute. The ventricles pump the blood out of the heart to the lungs or around the body.