Circulatory System
Circulatory refers to the continuous movement or flow of blood round the body involving the
heart and the blood vessels.
Types of circulatory System
Circulatory system in animals can be grouped into three categories:
a. Closed and open circulatory system.
b. Single and closed circulatory System.
c. Pulmonary Systemic circulatory system.
Closed and Open circulatory system:
i. The closed circulatory system are made up of the blood vessels called arteries from the heart
which branches many times into small units called capillaries. But eventually joins up with
other vessels called veins that are connected to the heart. By design, blood in these are always
confined within the cavities of the direct contact with body cells.
ii. Open circulatory system :In this system the blood vessels lead out of the heart but end in blood
spaces called haemocoels.
Single and Double Circulatory system:
i. Single circulatory system: In a single circulatory system, the blood only passes through the
heart once anytime it makes one complete movement round the body. The system is common
to fish which has only two chambered heart. One auricle and one ventricle.
ii. Double circulatory system: In this, the blood passes through twice anytime it make one
complete movement around the body. Each time the blood passes the heart, it goes separate
part ways, this is found in mammals. This give rise to pulmonary & system circulatory system.
Pulmonary and Systemic circulatory system:
• Pulmonary circulation: Pulmonary circulation involves only the heart
𝐻𝑏𝑂8 ⇔𝐻𝑏 + 4𝑂2 𝐻𝑏 + 4𝑂2 ⇔𝐻𝑏0
⬚ ⬚
During pulmonary circulation deoxygenated from the right ventricle is transported by the pulmonary
arteries into the lungs. The process of oxygen action takes place within the lungs. During this process
haemoglobin is made to combine with oxygen leading to the formation of oxyhaemoglobin. The
oxygenated blood is then collected by the pulmonary veins and then transported and then
Circulatory refers to the continuous movement or flow of blood round the body involving the
heart and the blood vessels.
Types of circulatory System
Circulatory system in animals can be grouped into three categories:
a. Closed and open circulatory system.
b. Single and closed circulatory System.
c. Pulmonary Systemic circulatory system.
Closed and Open circulatory system:
i. The closed circulatory system are made up of the blood vessels called arteries from the heart
which branches many times into small units called capillaries. But eventually joins up with
other vessels called veins that are connected to the heart. By design, blood in these are always
confined within the cavities of the direct contact with body cells.
ii. Open circulatory system :In this system the blood vessels lead out of the heart but end in blood
spaces called haemocoels.
Single and Double Circulatory system:
i. Single circulatory system: In a single circulatory system, the blood only passes through the
heart once anytime it makes one complete movement round the body. The system is common
to fish which has only two chambered heart. One auricle and one ventricle.
ii. Double circulatory system: In this, the blood passes through twice anytime it make one
complete movement around the body. Each time the blood passes the heart, it goes separate
part ways, this is found in mammals. This give rise to pulmonary & system circulatory system.
Pulmonary and Systemic circulatory system:
• Pulmonary circulation: Pulmonary circulation involves only the heart
𝐻𝑏𝑂8 ⇔𝐻𝑏 + 4𝑂2 𝐻𝑏 + 4𝑂2 ⇔𝐻𝑏0
⬚ ⬚
During pulmonary circulation deoxygenated from the right ventricle is transported by the pulmonary
arteries into the lungs. The process of oxygen action takes place within the lungs. During this process
haemoglobin is made to combine with oxygen leading to the formation of oxyhaemoglobin. The
oxygenated blood is then collected by the pulmonary veins and then transported and then
