BODY SYSTEMS RESPIRATORY SYSTEM
BREATHING Breathing is a function of your respiratory system. • respiratory system A system that consists of organs that supply the body with constant oxygen and rid the body of carbon dioxide • A person can only live a few minutes without oxygen.
FUNCTIONS respiration The exchange of gases between your body and the air
Respiration The entire process of exchanging gases between the atmosphere and the body cells. Ventilation – movement of air in and out of the lungs, commonly called breathing External respiration – exchange of gases between the air in the lungs and the blood Gases are transported by the blood between the lungs and body cells Internal respiration – exchange of gases between the blood and the body cells Cellular respiration – oxygen utilization and production of carbon dioxide by body cells
Organs of the respiratory system • Upper respiratory tract – nose, nasal cavities, sinuses and pharynx • Lower respiratory tract – larynx, trachea, bronchial tree and lungs • Nose – covered with skin, supported internally by muscle, bone & cartilage • Nasal cavity – a hollow space behind the nose, divided into a right and left half by the nasal septum • Nasal conchae – turbinate bones, divide the nasal cavity into passageways called the superior, middle and inferior meatuses • Fig 19.1 and 19.2
Organs of the respiratory system • Pharynx – located posterior to the oral cavity and between the nasal cavity and the larynx • Passageway for food and air • Aids in producing the sounds of speech • 3 subdivisions: nasopharynx, oropharynx, larynopharynx • Larynx – enlargement in the airway superior to the trachea and inferior to the pharynx, fig 19.6 • Passageway for air • Prevents foreign objects from entering the trachea • Houses the vocal cords • Cartilage complex – thyroid, cricoid, epiglottic, arytenoid, corniculate, and cunneiform. Fig 19.5
Organs of the respiratory system • False vocal cords – do not produce sound, help close the larynx during swallowing • True vocal cords – responsible for sound, also help prevent food or liquid from entering the trachea • Fig 19.7
Organs of the respiratory system • Trachea – a flexible cylindrical tube about 2.5 cm in diameter and 12.5 cm long • Extends downward anterior to the esophagus and into the thoracic cavity where it splits into the right and left bronchi • Fig 19.8 • Lined with ciliated mucous membrane that contains many goblet cells. Fig 19.10 • Filters air and moves the mucous upward to be swallowed • About 20 C-shaped hyaline cartilage pieces, which provide stability to prevent collapse and flexibility to bend as food passes through the esophagus. Fig 19.9
Organs of the respiratory system • Lungs – soft, spongy, cone-shaped organs located in the thoracic cavity • Separated into right and left halves by the heart and mediastinum • Enclosed by the diaphragm and the thoracic cage • Fig 19.19 • The right lung if larger than the left. • Right lung has 3 lobes, the left only 2 • Pleural cavity – the potential space between the visceral and parietal pleurae, contains only a thin film of serous fluid that lubricates the adjacent pleural surfaces, reducing friction as they move during breathing
PARTS OF THE RESPIRATORY SYSTEM Each lung is divided into sections called lobes. From the bronchi, air moves into smaller tubes called bronchioles. bronchi The main openings through which air enters the lungs
PARTS OF THE RESPIRATORY SYSTEM Bronchioles are divided into smaller spaces called alveoli. alveoli Tiny air sacs in the lungs where carbon monoxide is exchanged with oxygen
PARTS OF THE RESPIRATORY SYSTEM Lungs get their power from the diaphragm. diaphragm A dome-shaped muscle that separates the chest from the abdomen
Breathing Mechanism • Ventilation – breathing, the movement of air from outside the body into the bronchial tree and alveoli, followed by the reversal of the air movement • Inspiration – inhaling • Expiration – exhaling • Inspiration – the diaphragm contracts and moves downward creating negative air pressure inside the lungs, drawing in air from outside the body • Expiration – as the diaphragm relaxes and the thoracic cage returns to its normal position this increases the pressure in the pleural cavity and forces the air out • Figs 19.22 – 19.25
DIAPHRAGM WHEN YOU INHALE… The diaphragm contracts and flattens, permitting the lungs to expand and fill with air. WHEN YOU EXHALE… The diaphragm expands and moves upward, squeezing the lungs and forcing air out.
Controlling Breathing Normal breathing is a rhythmic, involuntary act that continues when a person is unconscious Groups of neurons in the brainstem comprise respiratory areas which control breathing The respiratory areas control the rate and depth of breathing to meet cellular needs for supply of oxygen and removal of carbon dioxide, even during strenuous physical exercise
PROBLEMS Asthma is the most common respiratory disease suffered by young people. asthma A serious, chronic condition that causes tiny air passages in the respiratory system to become narrow or blocked Asthma attacks are often triggered by an allergic reaction to substances in the environment.
PROBLEMS BRONCHITIS PNEUMONIA TUBERCULOSIS INFLUENZA CHRONIC OBSTRUCTIVE PULMANARY DISEASE “COPD” LUNG CANCER
CARE Knowing your area’s Air Quality Index (AQI) can help you maintain your respiratory health. Air Quality Index (AQI) A measure of ozone, sulfur dioxide, carbon monoxide, and fine particles close to the ground On days when air quality is poor, avoid outdoor activities.
CARE • EXERCISE MAKES LUNGS STRONGER • AVOIDING TOBACCO KEEPS LUNGS HEALTHY • PROTECT YOURSELF FROM RESPIRATORY INFECTIONS