Short notes on cardiac cycle

Cardiac cycle: The cardiac events that occur from the beginning of the one heart beat to the beginning of the next one is called cardiac cycle.
Cardiac cycle time: the normal cardiac cycle time is the 60/75 sec.=0.8 sec.
The events of cardiac cycle:
A. Electrical event/changes: Electrocardiogram.
B. Mechanical events/changes.
a. Pressure change: Venticular atrial is aortic and pulmonary arterial.
b. Volume change: Ventricular arterial.
c. Production of heart, sounds and apex beat.
Changes occur during cardiac cycle:
a. Changes in pressure
b. Changes in Volume
c. Production of heart sound.

Functions of Bones

1. Shae and support- Bones provide a frame work that supports the body and gives shape.
For example- The rib cage supports the thoracic wall and gives body shape.
2. Protection- Bones provide mechanical protection to vitasl organs.
For example- The skull bones protect the brain, the vertebrae protect the spinal cord, the rib cage protects the heart and lungs.
3. Movement- Bones allow movement of the body and its parts, by forming joints that are moved by muscles. As a result, we can walk, grasp objects, and breathe.
4. Mineral storage- bone is a reservoir for minerals, the most important of which are calcium phosphate. This is essential for maintenance of blood calcium levels.
5. Blood cell formation- This occurs in red bone marrow present in the marrow cavities of certain bones.