The Heart
| Home |Chapter: HAP - Cardiovascular System
The branch of science that deals with the study of the normal structure, function, and diseases of the heart is called Cardiology. (Cardio = heart, logy = study)
THE HEART
The
branch of science that deals with the study of the normal structure,
function, and diseases of the heart is called Cardiology.
(Cardio = heart, logy = study)
The
heart is the central organ of the cardiovascular system and acts as a powerful
muscular pump that maintains continuous blood circulation.
ANATOMY OF HEART
The
heart is a hollow, muscular organ located in the thoracic cavity.
Important
anatomical features of the heart are:
- It
lies between the two lungs, slightly towards the left side
- It
is cone-shaped, with a broad base above and a pointed apex below
- The
size of the heart is approximately equal to the closed fist of the
individual
- Average
dimensions:
- Length:
12 cm
- Width:
9 cm
- Thickness:
6 cm
- The
apex is located about 9 cm to the left of the midline at the level
of the fifth intercostal space
- The
base extends up to the level of the second rib
- Average
weight:
- Adult
female: 250 g
- Adult
male: 300 g
- It
rests on the diaphragm near the midline of the thoracic cavity
The
heart is situated in the mediastinum, which is the central space in the
thorax extending:
- From
sternum to vertebral column
- From
first rib to diaphragm
- Between
the two lungs
About
two-thirds of the heart lies to the left of the midline.
Organs
Associated with the Heart
|
DIRECTION |
ASSOCIATED STRUCTURES |
|
Inferiorly |
Central tendon of diaphragm |
|
Superiorly |
Aorta, superior vena cava, pulmonary artery,
pulmonary veins |
|
Posteriorly |
Oesophagus, trachea, bronchus, descending aorta,
inferior vena cava, thoracic duct |
|
Laterally |
Lungs (left lung overlaps the heart) |
|
Anteriorly |
Sternum, ribs, costal cartilages, pleura |
FUNCTIONS OF THE HEART
The
heart functions as a muscular pump that maintains constant blood
circulation.
The
sequence of blood flow is as follows:
1. Superior
vena cava and inferior vena cava bring deoxygenated
(venous) blood from the body to the right atrium
2. The
right atrium contracts, pushing blood into the right ventricle
3. The
right ventricle contracts, sending blood to the lungs through the pulmonary
trunk
4. In
the lungs, blood becomes oxygenated
5. Oxygenated
blood returns to the left atrium through pulmonary veins
6. The
left atrium contracts, sending blood into the left ventricle
7. The
left ventricle contracts, pumping blood into the aorta, which
supplies blood to the entire body
This
continuous pumping action ensures proper circulation.
