BIOL239 General Anatomy - Lecture 12 - Spring 2025

  • Immune System:

    • Innate Immunity: Non-specific defense.

    • Adaptive Immunity: Specific, remembers infections for faster response.

  • White Blood Cells:

    • Act as internal defense.

    • Phagocytes: Engulf pathogens, examples include Neutrophils and Macrophages.

  • Inflammation:

    • Coordinated response to injury/infection.

    • Mast cells release histamine, causing leaky capillaries.

    • Macrophages release cytokines, recruiting immune cells.

  • Adaptive Immune System:

    • Phagocytes display pathogen pieces using MHC.

    • Helper T cells activate B cells.

    • Plasma cells (activated B cells) produce antibodies.

    • Cytotoxic T cells kill infected cells via apoptosis.

    • B lymphocytes create antibodies to mark bacteria for destruction.

  • Respiration:

    • Key processes: Pulmonary ventilation, External respiration, Gas transport, Internal respiration.

    • Functions: Supplies O2, removes CO2.

    • Organs: Nose, Pharynx, Larynx, Trachea, Bronchi, Lungs.

  • Nasal Cavity:

    • Olfactory Mucosa: Contains smell receptors.

    • Respiratory Mucosa: Contains goblet cells and ciliated epithelium.

  • Pharynx (Throat):

    • Regions: Nasopharynx (air), Oropharynx, Laryngopharynx (air and food).

  • Larynx:

    • Functions: Voice production, keeps airway open, routes air and food properly.

  • Bronchial Tree:

    • Primary, Secondary, Tertiary bronchi branch extensively.

  • Alveoli:

    • Site of gas exchange.

    • Type I and II alveolar cells, macrophages.

  • Breathing:

    • Relies on diaphragm and rib muscles contracting and relaxing.

  • Inspiration:

    • Thoracic cavity volume increases.

    • Diaphragm flattens and external intercostal muscles contract.

  • Neural Control of Ventilation

    • Chemoreceptors sensitive to O2, CO2, and pH levels.

    • Peripheral chemoreceptors in aortic arch and carotid arteries.

  • Gas Transportation:

    • CO<em>2CO<em>2 mainly transported as bicarbonate ( HCO</em>3−HCO</em>3^-
      ).

    • Key equation: CO<em>2+H</em>2O⇌H<em>2CO</em>3⇌H++HCO3−CO<em>2 + H</em>2O \rightleftharpoons H<em>2CO</em>3 \rightleftharpoons H^+ + HCO_3^-

  • Neural Control of Ventilation:

    • Respiratory centers in the brainstem control diaphragm and intercostal muscles.

    • Promotes contraction of diaphragm and intercostals