Respiratory pt 1

Overview of the Respiratory System

• Connected to the circulatory system, especially in the transport of gases.

• Critical functions include ventilation, respiration, gas exchange, and more.

Key Components of Blood

• Erythrocytes (Red Blood Cells): Responsible for carrying oxygen; they contain hemoglobin, which binds oxygen.

• Heme Group: Contains iron; plays a vital role in oxygen transport.

• Carbon Dioxide: Exhaled through the respiratory system after oxygen is delivered to cells.

Functions of the Respiratory System

1. Pulmonary Ventilation:

   • Involves inhalation (inspiration) and exhalation (expiration).

   • Ensures airflow into and out of lungs.

2. External Respiration:

   • Gas exchange occurring between air in the lungs and blood in pulmonary capillaries.

   • Oxygen enters blood, carbon dioxide leaves.

3. Transport of Gases:

   • Oxygenated blood travels from lungs to heart and then to systemic capillaries.

4. Internal Respiration:

   • Exchange of gases between blood and tissues.

Additional Functions of the Respiratory System

• Regulation of Blood pH:

  • Changes in carbon dioxide levels influenced by the enzyme carbonic anhydrase can alter blood acidity.

• Sound Production:

  • Structures in the larynx allow for phonation when air passes.

• Olfaction:

  • Smelling process initiated through air entering the nasal cavity and stimulating olfactory receptors (Cranial Nerve I).

• Protection Against Pathogens:

  • Physical barriers such as mucus and nasal hairs combat viruses and bacteria.

Anatomy of the Respiratory System

Upper Respiratory Tract

• Nose: Entry point for air, composed of both cartilage and bone; contains nostrils (nares).

• Nasal Cavity: Lined with mucous membranes to warm and humidify air; contains nasal conchae to increase surface area.

• Pharynx: Divided into three sections:

  1. Nasopharynx: Contains adenoids and connects to the eustachian tube.

  2. Oropharynx: Visible when person opens their mouth.

  3. Laryngopharynx: Funnels air into the larynx and food into the esophagus.

Lower Respiratory Tract

• Larynx (Voice Box):

  • Composed of cartilage and structures that support phonation.

  • Key cartilages:

    1. Thyroid Cartilage: Forms the Adam's apple, larger in males.

    2. Cricoid Cartilage: Ring-shaped and helps maintain air passage.

    3. Epiglottis: Leaf-shaped, prevents food from entering the trachea during swallowing.

• Trachea:

  • Contains C-shaped hyaline cartilage; lined with ciliated epithelium to trap debris.

  • Splits into primary bronchi at T4 level (carina).

Bronchi and Bronchioles

• Primary Bronchi: Right and left main stems conducting air to lungs.

• Secondary Bronchi: Supplies air to lobes of each lung.

  • Right Lung: 3 lobes; Left Lung: 2 lobes.

• Tertiary Bronchi: Further divide into smaller bronchioles.

Gas Exchange Mechanism

• In alveoli, oxygen is exchanged for carbon dioxide through diffusion into the bloodstream.

• Newly oxygenated blood moves through pulmonary veins to the left atrium of the heart.

Considerations for Breathing

• Diaphragm Movement: Essential for inhalation and exhalation.

• Cough Reflex: Triggered by irritants or blockages in the trachea.

Summary

The respiratory system plays a vital role in gas exchange, aiding in maintaining blood pH, allowing for sound production, and providing a sense of smell. Understanding its anatomy—from the upper respiratory tract down through the larynx and trachea into the bronchi—helps elucidate how it operates in conjunction with the circulatory system.