Respiratory System

Functions of the Respiratory System

\- main function is breathing, inhalation and exhalation

\- gas conditioning

\- sound production

\- olfaction

\- defense

Upper Respiratory Tract

\- nose

\- paranasal sinuses

\- pharynx

Lower Respiratory Tract

\- larynx

\- trachea

\- bronchi and bronchioles

\- lungs

External Nose

\- framed by frontal, nasal, and maxillary bones

\- very thin skin with lots of sebaceous glands

\- nasal bones form “bridge” of nose, two pairs of cartilage frame rest of nose

Internal Nose

\- nasal cavity divided by the nasal septum

\- warms, filters and moistens incoming air

\- olfaction and speech modification

Deviated Septum

\- caused from blunt trauma or improper growth

\- symptoms include: sinus infections, snoring, sneezing, nosebleeds and difficulty breathing

Paranasal Sinuses

\- small openings in the frontal, ethmoid, sphenoid and maxillary bones for sinus cavities

\- lighten the weight of the head

\- humidifies and heats inhaled air

\- speech modification

\- protection of facial structures

Sinusitis

\- caused by infections or allergies

\- sinus tissues get inflamed, swollen and red

Pharynx

\- connects the nasal cavity/mouth to the larynx/esophagus

\- three regions: nasopharynx, oropharynx and laryngopharynx

Nasopharynx

\- posterior to the nasal cavity, serving only as an air passageway

\- contains the pharyngeal tonsils that can become inflamed and cause difficulty breathing

\- pseudostratified columnar epithelium

Oropharynx

\- posterior to the oral cavity, food and air pass through it

\- stratified squamous epithelium

Laryngopharynx

\- passageway for food and air

\- stratified squamous epithelium

\- directs food into esophagus

\- air into trachea pharynx

\- food gets preference

Larynx

\- voice box with an intricate arrangement of nine cartilages (3 types)

Thyroid Cartilage

\- larger in males

\- prominence is Adam’s apple

Cricoid Cartilage

\- only cartilage to form a complete ring around larynx

Arytenoid Cartilage

\- anchor the vocal cords along with two other pairs of cartilage

Sound Protection

\- vocal folds consist of vocal ligaments

\- covered by mucous membrane

\- when air is forced through space between vocal ligaments, vibrations of vocal folds resulting in the production of sound

Laryngitis

\- vocal cords run between arytenoid and thyroid cartilages

\- inflammation of the larynx

\- vocal cords swell an interfere with their ability to vibrate

Trachea

\- descends from larynx through neck into mediastinum, ends by dividing into primary bronchi

\- contains 16-20 C-shaped rings of hyaline cartilage making it flexible enough to bend, and prevent it from collapsing

\- inner membrane consists of ciliated epithelium that keeps the passageway free of dust

Tracheostomy

\- when trachea is blocked (foreign object, injury, infection), tracheostomy may be required

\- intubation (pushing a tube through pharynx and larynx) another option

Bronchiole Tree

\- trachea bifurcates into primary bronchi at the carina, going into each lung

\- bronchi enters the lung dividing into secondary bronchi, passing into each lung

\- further divides into tertiary bronchi then bronchioles, less cartilage and more smooth muscle

Alveoli

\- about 300 million to provide a large space for gas exchange

Type I Alveolar Cells

\- simple squamous epithelial cells

\- promotes rapid diffusion of gases

Type II Alveolar Cells

\- cuboidal in shape

\- produce pulmonary surfactant

\- prevents collapse of alveoli

Asthma

\- muscles around the bronchioles tighten

\- lining of the bronchioles swell and get clogged with mucous

Visceral Pleura

\- flattened sac surrounding the lungs

Parietal Pleura

\- covers the thoracic wall

Pleural Cavity

\- space between the visceral and parietal pleura

Pleurisy

\- inflammation of the pleura caused by the rubbing together of the membranes leading to pain with breathing

Lungs

\- made up of air tubes, space and stroma

Stroma

\- framework of connective tissue with many elastic fibers and an extensive network of blood vessels

\- pulmonary arteries branch with branches of the bronchial tree and form a network around individual alveoli

Emphysema

\- lung disease involving damage to the alveoli

\- large air cysts develop where normal lung tissue used to be

\- air is trapped in the lungs due to lack of supportive tissue

Bronchitis

\- inflammation of the air passages in the lungs

\- symptoms include excessive bronchial mucus with a cough producing sputum

\- chronic or acute

Chronic Obstructive Pulmonary Disease

\- effects are irreversible

\- about 80% of patients are smokers

\- results in high blood levels of CO2 and low levels of O2

\- often tired because accessory muscles required to breathe

Pneumonia

\- inflammation of the lung typically caused by an infection

\- serious lung condition where the lungs fill with fluid

\- can be caused by bacteria, fungus, or a virus

\- can be mild, severe, or fatal

Tuberculosis

\- bacterial infection that causes more deaths than any other infectious disease

\- caused by Myobacterium tuberculosis (bacillus)

\- about 2 billion people infected worldwide

\- when it becomes active, kills about 60% of people untreated (about 3 million deaths worldwide)

\- if treated, about 90% of patients survive

\- attacks the lungs but can also affect other body systems

Lung Cancer

\- uncontrolled cell growth in lung tissue

\- majority of lung cancers are carcinomas, derived from epithelial cells

\- non-small cell lung carcinoma are sometimes treated with surgery (more common)

\- small cell lung carcinoma responds better to chemotherapy and radiation (less common)

Cystic Fibrosis

\- condition in which glands produce excessively sticky mucous that clogs the lungs, liver, pancreas and intestines, making it difficult to breathe and digest food

\- hereditary disease caused by a recessive mutation