Cardiac cycle

Cardiac cycle

The cardiac cycle is the series of events that occur during one complete heartbeat. It is a complex process that involves the contraction and relaxation of the heart’s chambers, the opening and closing of valves, and the movement of blood through the heart and circulatory system.

The cardiac cycle can be divided into two main phases: diastole and systole.

1. Diastole: This is the relaxation phase of the cardiac cycle, during which the heart’s chambers are filling with blood. In the first part of diastole, the atria contract, forcing blood into the ventricles. This is followed by a period of passive filling, during which the atria and ventricles are relaxed and blood flows from the veins into the atria and then into the ventricles. The AV valves, which separate the atria and ventricles, are open during this phase, while the semilunar valves, which separate the ventricles and arteries, are closed.
2. Systole: This is the contraction phase of the cardiac cycle, during which the heart’s chambers are emptying blood into the circulatory system. In the first part of systole, the ventricles contract, forcing blood out of the heart and into the arteries. This is followed by a brief period of isovolumic relaxation, during which the ventricles and atria are relaxed and all the heart valves are closed. The cycle then begins again with the next diastole.

The cardiac cycle is controlled by the heart’s electrical conduction system, which coordinates the timing of the contractions and relaxations of the heart’s chambers. It is also influenced by a variety of factors, including the autonomic nervous system, hormones, and the body’s need for oxygen and nutrients.

In summary, the cardiac cycle is the series of events that occur during one complete heartbeat, and it involves the contraction and relaxation of the heart’s chambers, the opening and closing of valves, and the movement of blood through the heart and circulatory system. It is divided into two main phases, diastole and systole, and is controlled by the heart’s electrical conduction system and influenced by a variety of factors.

First Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise

F Y B Pharm Sem-I	F Y B Pharm Sem-II
BP101T Human Anatomy and Physiology I Theory	BP201T Human Anatomy and Physiology II – Theory
BP102T Pharmaceutical Analysis I Theory	BP202T Pharmaceutical Organic Chemistry I Theory
BP103T Pharmaceutics I Theory	BP203T Biochemistry – Theory
BP104T Pharmaceutical Inorganic Chemistry Theory	BP204T Pathophysiology – Theory
BP105T Communication skills Theory	BP205T Computer Applications in Pharmacy Theory
BP106RBT Remedial Biology	BP206T Environmental sciences – Theory
BP106RMT Remedial Mathematics Theory	BP207P Human Anatomy and Physiology II Practical
BP107P Human Anatomy and Physiology Practical	BP208P Pharmaceutical Organic Chemistry I Practical
BP108P Pharmaceutical Analysis I Practical	BP209P Biochemistry Practical
BP109P Pharmaceutics I Practical	BP210P Computer Applications in Pharmacy Practical
BP110P Pharmaceutical Inorganic Chemistry Practical
BP111P Communication skills Practical
BP112RBP Remedial Biology Practical

Suggested readings:

• Cardiac output: Human heart
• Anatomy of heart
• Microscopic study of muscular and nervous tissue
• Elements of the conduction system of heart and heartbeat
• Hair growth cycle