FIRST AID AND EMERGENCY CARE LECTURE 3 ANATOMY AND PHYSIOLOGY Respiratory System

UNDERSTANDING VITAL BODY FUNCTIONS FOR FIRST AID In order for the service member to learn to perform first aid procedures, he must have a basic understanding of what the vital body functions are and what the result will be if they are damaged or not functioning.

THE RESPIRATORY SYSTEM COMPONENTS OF THE RESPIRATORY SYSTEM 1.The Airway 2.The neuromuscular system 3.The Alveoli 4.The vascular system, arteries, capillaries & veins

The Airway Upper airway: Consists of Nose and mouth, Pharynx, Larynx Lower airway: Consists of Trachea, Bronchi (right and left), Bronchioles

The Neuromuscular System Respiratory centre in the brain Nerves Muscles of respiration, These are: 1.Diaphragm 2.Intercostal muscles 3.Some muscles in the neck and shoulder girdle

Chest cage, protect the lungs and the heart. It surrounded by the spine at the back, the sternum in front, and the ribs around

The Alveoli They are minute air sacs, millions in number. They are made of a very delicate thin membrane of one cell layer forming a fine network. The capillaries are on the outer side of the alveoli where exchange of gases takes place.

Pulmonary Vessels They are arteries that carry dark-colored blood with low oxygen levels from the heart to the fine network of capillaries where Oxygen (O2) is picked-up by the blood and Carbon Dioxide (CO2) is expelled out of the alveoli. The oxygenated blood is then carried out to the left side of the heart by the veins to be distributed to the various body organs and tissues.

All artery carry oxygenated blood except pulmonary artery All vein carry deoxygenated blood except pulmonary vein

PHYSIOLOGY OF RESPIRATION The function of the respiratory system is to pick- up oxygen from the air and expels carbon dioxide into the air. Metabolism is a continuous process which needs oxygen to function and as a result of this process, carbon dioxide is produced. The Cardiovascular system transports oxygen from the lungs to the cells and transports carbon dioxide from the cells to the lungs for elimination.

The Breathing Process All humans must have oxygen to live. Through the breathing process, the lungs draw oxygen from the air and put it into the blood. The heart pumps the blood through the body to be used by the cells that require a constant supply of oxygen. Some cells are more dependent on a constant supply of oxygen than others. For example, cells of the brain may die within 4 to 6 minutes without oxygen. Once these cells die, they are lost forever since they do not regenerate. This could result in permanent brain damage, paralysis, or death.

The breathing mechanism is controlled and influenced by the respiratory centre in the brain and primarily the rate and depth of breathing is stimulated by carbon dioxide in the arterial blood. As the level rises, the respiratory centre sends a continuous parade of signals via the nerves to respiratory muscles. This will result in an increasing rate and depth of breathing until the level of carbon dioxide falls, then the breathing rate and depth are returned to normal. This is known as feedback mechanism between carbon dioxide level and the rate and depth of breathing.

ExpiredInspired AirGas 16%21%O2 4%0.03%CO2 79% N2 MoreLessHumidity

During respiration, 5% of oxygen passes from atmospheric air into the blood through alveolar and capillary walls and 4% of carbon dioxide is eliminated from the blood into the expired air. Inspiration is an active process while expiration is a passive process. Respiration Respiration occurs when a person inhales (oxygen is taken into the body) and then exhales (carbon dioxide [CO2] is expelled from the body).

THE CARDIOVASCULAR SYSTEM The Cardiovascular System composed of: 1.The Heart 2.The blood vessels (Arteries, Capillaries, Veins)

THE HEART Fist-sized organ situated in the center of the chest between the sternum and the spine and above the diaphragm It is surrounded by the lungs except in small area in front of the heart known as the bare area and the area against the spine It has a hollow tough muscular wall surrounded by the pericardium It is divided into right and left sides and each side has two chambers (right atrium and right ventricle, and left atrium and left ventricle)

THE VASCULAR SYSTEM The cardiovascular system composed of: Arteries: Thick-walled, carrying blood from the heart under high pressure. Capillaries: Thin network of one cell layer. Veins: Thin-walled vessels that carry blood under low pressure back to the heart.

PHYSIOLOGY OF THE HEART Heart pumps blood from the right ventricle into the pulmonary artery to the lungs to purify the blood and from the left ventricle into the aorta to distribute blood to the rest of the body. Arteries carry blood away from the heart Veins carry blood back to the heart Exchange of gases takes place in the capillary system throughout the body.

FUNCTIONS OF THE CARDIOVASCULAR SYSTEM To purify the blood through the pulmonary capillary system To provide oxygenated blood and nutrient to all tissues, through the systemic capillary system. The heart beats beats/minute during rest The amount of blood pumped by a single beat and known as the stroke volume is ~70ml.

The heart pumps ~5 liters/minute Cardiac output is equal to stroke volume multiplied by heart beats/min. That is to say 70x70=4900 (5 liters/min). The heart can beat faster, up to beats/min during exercise, so it is capable of pumping up to 35 liters per minute.

BLOOD SUPPLY TO THE MYOCARDIUM Two coronary arteries, right and left, originate from the first part of the aorta. They are divided into several branches which encircles the heart to supply the myocardium. The coronary arteries are end arteries. There is no venous coronary artery.

Heart Beats at Rest Heart beat/minute = 70x1 = 7 Heart beat/hour = 70x60 = 4,200 Heart beat/day = 4200x24 = 100,800 Heart beat/year = 100,800x365 = 6,792,00 Volume pumped/min = 5lit Volume pumped/hour = 5x60 = 300 lit Volume pumped/day = 300x24 = 7200 li Volume pumped/year = 7200x365 lit = 2,628,000lit