Respiratory System Overview

Respiratory System Overview

• Breathing is essential for life, representing the first breath of a baby and the last gasp of a dying person.
• Respiration is crucial for metabolism due to ATP synthesis requiring oxygen and producing carbon dioxide.
• The respiratory system's primary function is to deliver oxygen to the blood and remove carbon dioxide.
• It's a complex system involving tubes carrying air to the lungs, facilitating an exchange of oxygen and carbon dioxide.

Respiratory System Functions

• Conducting Air: Bringing air to the lungs for gas exchange; this includes the nose, pharynx (throat), larynx (voice box), trachea (windpipe), bronchi.
• Gas Exchange: Oxygen diffuses into the blood, and carbon dioxide diffuses out of the blood in the alveoli (air sacs) of the lungs.
• Communication: Speech and sound production via the larynx.
• Olfaction: Sense of smell, facilitated by receptors in the nose.
• Acid-Base Balance: Breathing maintains the correct balance of acids and bases in the body.
• Blood Pressure Regulation: The respiratory system helps regulate blood pressure.
• Expulsion of Abdominal Contents: Breathing assists in expelling abdominal contents.
• Other Functions: The respiratory system contributes to various body functions, including speech, olfaction, and maintaining acid-base balance.

Respiratory Tract Divisions

• Upper Respiratory Tract: Nose, nasal cavity, paranasal sinuses, pharynx.
• Lower Respiratory Tract: Larynx, trachea, bronchi, bronchioles, alveoli.

Nose (Nasus)

• Functions: Warms, cleanses, and humidifies inhaled air; detects odors; and amplifies the voice.
• Structure: Facial part is composed of bone and cartilage; it extends from nostrils to posterior nasal apertures.
• Internal Structure: Consists of three conchae (turbinates), which increase surface area for filtering and warming air.

Pharynx (Throat)

• Muscular funnel, approximately 13 cm long, connecting the nasal and oral cavities to the larynx and esophagus.
• Regions: Nasopharynx (superior part), oropharynx (middle part), laryngopharynx (inferior part).

Larynx (Voice Box)

• Cartilaginous structure that connects the pharynx to the trachea and has a role in voice production (phonation).
• Epiglottis covers the opening, preventing food or liquid from entering the respiratory tract.
• Cartilages include thyroid, cricoid, epiglottic, and arytenoid.

Trachea (Windpipe)

• Tubular structure extending from the larynx's inferior end to the bronchi.
• Composed of C-shaped cartilage rings that provide structural support preventing collapse.

Bronchi and Bronchioles

• Trachea bifurcates into two main bronchi entering the lungs: right and left.
• Divided into secondary and tertiary bronchi as well as bronchioles, which lead to the microscopic alveoli.
• Bronchi have cartilaginous rings to prevent collapse during breathing.

Lungs

• Paired organs responsible for gas exchange.
• Each lung has three lobes (right lung) or two lobes (left lung): superior, middle, and inferior.
• Lobes are separated by fissures; the left lung has an indentation called the cardiac notch.

Pleura

• Two-layered serous membrane surrounding the lungs reducing friction during breathing.
• Visceral pleura adheres tightly to the lung; parietal pleura lines the chest cavity.
• Pleural cavity is the space between the two pleura filled with fluid, preventing friction during breathing.