تركيب ووظيفة الدم والقلب

Composition of Blood

• Blood is composed of red blood cells, white blood cells, platelets, and plasma.
• Red blood cells transport oxygen.
• White blood cells fight infections.
• Plasma transports chemicals, maintaining body temperature.
• Platelets clump together to form blood clots.

Structure and Function of the Heart

• The heart is roughly the size of a clenched fist and located in the left side of the chest.
• It is made of cardiac muscle.
• The heart contracts to pump blood throughout the body.
• The right side pumps blood to the lungs.
• The left side pumps blood to the rest of the body.
• It has four chambers: two atria (left and right) and two ventricles (left and right).

Blood Vessels

• Arteries: Carry blood away from the heart at high pressure. Walls are thick and strong to withstand this pressure. Lack valves.
• Veins: Return blood to the heart at low pressure. Walls are thinner and weaker. Contain valves to prevent backflow.
• Capillaries: Tiny blood vessels connecting arteries and veins. Thin walls allow for the diffusion of materials in and out of the blood.

Taking a Pulse

• To take a pulse, gently press your hand on your wrist or the side of your neck.

Benefits of Exercise

• Regular exercise helps reduce the risk of heart disease, diabetes, and certain cancers.
• It assists with weight management.