In previous classes, we learnt about the breathing system, the digestive system and the reproductive system.
In this class, we shall learn about the circulatory system. In circulatory system blood circulates materials throughout the body. Therefore, the blood system is known as the circulatory system.
The circulatory system is made up of the heart, arteries, capillaries and veins. The system transports blood and other materials all over the body.
The circulatory system in human beings is responsible for transporting blood and other dissolved materials in the body. It is made up of the:
The heart is a muscular organ that pumps blood throughout the body. It lies in between the lungs, slightly to the left side of the body, in the chest cavity. The heart is protected from injury by the chest.
The heart has thick and strong muscles. These muscles can relax and contract. When the muscles contract, the heart pumps blood out under high pressure. This contracting and relaxing of the heart muscles is called then heartbeat.
Do you feel the same as in 1 above?
Use a watch or clock to count the number of beats in one minute.
The heart of an adult beats approximately 72 times in one minute. The heartbeats are also called pulses. The number of times the heart beats in a minute is called the pulse rate.
The heart beats faster when we are active. This is to provide more oxygen to the active muscles so as to help generate more energy. It also beats faster in children, when people are excited, ill or fearful people.
When one has an injury, the red liquid that flows out of the injured part is called blood.
Blood contains:
Hormones are chemicals that control growth and other activities in the body.
An adult human being has about five litres of blood flowing in the body.
Blood is contained in tubes called blood vessels. These tubes carry blood to all parts of the body.
Avoid touching other people’s blood because blood can spread HIV; the virus that causes AIDS. You should wear protective gloves when assisting an injured person.
Choose the files you want to add. Supported formats are txt, html, htm, pdf, odt, odp, ods, xls, xlsx, ppt, pptx, pps, doc, docx, rtf, png, jpg, jpeg and gif.
| Name | |
|---|---|
| remove |
NB! Links must begin with: “http://”!
Opiq uses essential cookies to make our website work, to help keep you safe, to analyse user interaction and to improve user experience.
Cookie is a small file which is sent from users computer to the website server. It includes necessary information for the website to operate and includes information about the user and their preferences.
Most of the cookies are necessary for the operation of Opiq. It is possible to deny analytical cookies and in that case your usage data is not used to develop and improve Opiq services. Read more