Unit 16: Abdomen & Thoracic Injuries Lesson 2: Anatomy of the Thorax

Objective: Recognize relevant anatomy of the thorax

Terminology Atrium: Intercostal Thorax Ventricle The upper chambers of the heart Intercostal refers to the area between the ribs Thorax the chest; the part of the body located between the neck and the abdomen Ventricle lower chamber of the heart

Terms in Pictures Atrium Intercostal Thorax Ventricle

Thoracic Cavity Boarders Superior Clavicle Inferior Diaphragm Anterior Sternum, ribs and intercostal muscles Posterior Spine, ribs, scapulae & erector spinae muscle

Rib Cage Anatomy 12 pairs of ribs True ribs (first 7 pairs): attach directly to the sternum by individual cartilage False ribs (next 3 pairs): attach indirectly to the sternum by shared cartilage Floating ribs (next 2 pairs): have no attachment to the sternum

Organs of the Thoracic Cavity Esophagus Trachea Lungs Heart

The Esophagus Location: In the throat, behind the trachea Function: Structure for food to pass from the mouth to the stomach

Location: Function: The Trachea A cartilage structure in the throat, directly in front of the esophagus The trachea divides into 2 branches (bronchi) which enter the lungs Function: Allows air to pass into and out of the lungs

Location: Functions: The Lungs Exchange carbon dioxide for oxygen On either side of the heart Functions: Exchange carbon dioxide for oxygen Help to remove heat from the body

Location: Function: The heart Under the sternum (slightly to the left) and between the lungs Function: to pump blood throughout the body Blood carries oxygen and nutrients to the cells Blood carries carbon dioxide and waste products away from the cells

The Heart Divided into 4 chambers R and L atrium (upper chambers) R and L ventricles (lower chambers) Heart valves separate each chamber and prevent a backflow of the blood Tricuspid valve Biscuspid (mitral) valve Pulmonary valve Aortic valve

Direction blood pumps through the heart

How does the blood flow through the Heart? Left Side of Heart Right Side of Heart The pulmonary veins empty oxygen-rich blood from the lungs into the left atrium of the heart. As the atrium contracts, blood flows from your left atrium into your left ventricle through the open mitral valve. When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts. As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body. Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve. When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts. As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs, where it is oxygenated and then returns to the left atrium through the pulmonary veins. http://www.webmd.com/heart-disease/guide/how-heart-works?page=3

How blood flows through the lungs Once blood travels through the pulmonic valve, it enters your lungs. This is called the pulmonary circulation. From your pulmonic valve, blood travels to the pulmonary artery to tiny capillary vessels in the lungs. Here, oxygen travels from the tiny air sacs in the lungs, through the walls of the capillaries, into the blood. At the same time, carbon dioxide, a waste product of metabolism, passes from the blood into the air sacs. Carbon dioxide leaves the body when you exhale. Once the blood is purified and oxygenated, it travels back to the left atrium through the pulmonary veins.