Respiratory System

Respiratory system

Also called pulmonary system. Series of organs responsible for taking in oxygen and expelling carbon dioxide.

Contains lungs which carries out exchange of gases when we breathe

Red blood cells collect oxygen from lungs and carry it to body. Red blood cells then collect CO2 from body tissues and bring it back to lungs to be exhaled.

Sections of lungs

Right lung: Superior, middle, inferior lobe.

Left lung: Superior, inferior lobe

Structure of lungs

Outside to inside

Chest wall, parietal pleura, pleural cavity, visceral pleura.

Diaphragm underneath

Lung margins: midclavicular line

Margin of lung: 6th rib

Margin of pleura: 8th rib

Lung margins: midacillary line

Margin of lung: 8th rib

Margin of pleura: 10th rib

Lung margins: midscapular line

Margin of lung: 10th rib

Margin of pleura: 12th rib

Air flow through the lungs

Nose/mouth → pharynx → larynx → trachea → right/left primary bronchus → right/left secondary bronchi → tertiary bronchi → bronchioles → alveoli

Gas exchange in alveoli

deoxygenated blood enters. CO2 leaves blood and enters alveoli. O2 leaves alveoli and enters blood. Oxygenated blood leaves

Mechanics of breathing: Inhalation

diaphragm contracts, chest expands, lowering the pressure in the lungs. Air comes into the lungs.

Mechanics of breathing: exhalation

diaphragm relaxes, chest compresses, increasing pressure in lungs. Air leaves the lungs

Upper/lower respiratory infection

Caused by viruses and sometimes bacteria.

Upper respiratory tract infections: affect nosee, sinuses, throat

Lower respiratory tract infections: affect the airways and lungs

Asthma

Lining of bronchial tubes swell, airways narrow, reducing flow of air into/out of lungs

Pneumonia

alveoli fill with pus (dead neutrophils) and fluid, making breathing painful and limiting oxygen intake.

Chronic Obstructive Pulmonary Disease (COPD)

lung ailment characterized by consistent blockage of airflow from the lungs.

Caused by tobacco smoking

Includes: emphysema, chronic bronchitis

Newborn Acute Respiratory Distress Syndrome (ARDS)

Often seen in premature babies. Caused by lack of surfactant. Results in lung inflammation, damage to alveolar-capillary barrier, and hypoxemia

Surfactant

slippery substance that helps the lungs fill with air and prevents air sacs from deflating. Is present when lungs are fully developed

Tuberculosis

Caused by myobacterium tuberculosis

Symptoms: cough, fever, bloody phlegm, fatigue.

Causes cavities in the lung

Lung cancer

Most common cancer. Leading cause of cancer death in men and women in US

Leading cause of lung cancer is cigarette smoking.

High levels of pollution, radiation, and asbestos exposure increases risk.

Pneumothorax

Abnormal collection of air or gas in the pleural space that causes and uncoupling of the lung from the chest wall.

Caused by chest injury or disease or ruptured air blisters.

Symptoms: sudden onset dyspnea, chest pain.

spontaneous pneumothorax

rupture of subpleural bleb. Air rushes from lungs into pleural space, lungs collapse.

Tension pneumothorax

Progressive build up of air in pleural space.

Pleural Effusion

Excess fluid accumulates in the pleural cavity. Can impair breathing by limiting the expansion of the lungs

Causes:

• Exudative (leaky vessels)

  • Tuberculosis

  • Paraneumonic

    • Pneumonia

    • lung abscess

    • bronchiectasis

  • Malignancy

  • Pulmonary embolism

• Transudative (pressure build up)

  • Congestive Heart Failure (CHF)

  • Nephrotic syndrome

  • Liver cirrhosis

Hemothorax

Abnormal blood collection in the pleural space that causes an uncoupling of the lung from the chest wall