An object falling without any air resistance under the influence of gravitational force is said to be in free-fall. For free-falling bodies, the acceleration due to gravity is constant, irrespective of their mass. Free-fall is experienced not only by objects falling downward, but also by all objects whose motion is influenced by gravitational force alone. The dynamics of free-fall motion can be calculated using kinematic equations of motion, since free-fall acceleration is constant.
The...

All objects, neglecting air resistance, fall with the same acceleration towards the Earth's center due to the force exerted by the Earth's gravity. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavier ones. People believed that a heavier object had a greater acceleration when falling until Galileo Galilei (1564–1642) proved otherwise. We now know this is...

The thoracic section of the aorta begins at the T5 vertebra and extends to the T12 level at the diaphragm, initially progressing through the mediastinum to the left of the spinal column. Throughout its course in the thoracic segment, the thoracic aorta emits various offshoots known collectively as visceral and parietal branches. The branches that predominantly supply blood to visceral organs are termed visceral branches and include bronchial, pericardial, esophageal, and mediastinal arteries,...

The thoracic or rib cage forms the body's thorax (chest) portion. Its primary function in the body is to protect vital organs in the thoracic cavity, such as the heart and the lungs. It consists of 12 pairs of ribs with their costal cartilages and the sternum. The ribs are anchored posteriorly to the 12 thoracic vertebrae (T1-T12).
The sternum is the elongated bony structure on the anterior side of the thoracic cage. It consists of three parts: the manubrium, the body, and the xiphoid...

Ribs are curved, flattened bones forming the thoracic cavity wall with the thoracic muscles. There are 12 pairs of thoracic ribs. The posterior ends of all the ribs articulate with the T1–T12 thoracic vertebrae. In contrast,the anterior ends of most ribs attach to the sternum via their costal cartilages.
Parts of a Typical Rib
A typical rib has a head, neck, and body. The posterior end of the rib is called the head, followed by a narrow neck. The head articulates primarily with the costal...

Breathing, otherwise known as pulmonary ventilation, is the process of air movement into and out of the lungs. The main mechanisms propelling pulmonary ventilation are atmospheric pressure (Patm), intra-pulmonary (Ppul ) or intra-alveolar pressure (Palv) within the alveoli, and intrapleural pressure (Pip) within the pleural cavity.
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs...