Role in Homeostasis: The respiratory system maintains homeostasis by regulating oxygen and carbon dioxide levels in the body.
Inspiration vs. Expiration: Understand the difference between the two phases of ventilation: inspiration (inhalation) brings air into the lungs, while expiration (exhalation) expels air out of the lungs.
Structures: Identify key anatomical structures involved in respiration.
Function: Facilitates the exchange of oxygen (O2) and carbon dioxide (CO2).
Inspiration: Air moves from the atmosphere via cavities and tubes into the lungs.
Expiration: Air flows from the lungs back to the atmosphere through the same pathways.
Upper Respiratory Tract:
Nasal Cavity: Filters, warms, and moistens incoming air.
Pharynx: Common passageway for air and food.
Glottis: Vocal cords and the space between them.
Larynx (Voice Box): Produces sound.
Trachea (Windpipe): Conducts air to the lungs.
Lower Respiratory Tract:
Bronchus: Air passage to the lungs; branches into bronchioles.
Bronchioles: Small air passageways leading to alveoli.
Lungs: Contain alveoli where gas exchange occurs.
Diaphragm: Muscle that aids in ventilation.
Ventilation (Breathing): Consists of inspiration and expiration; relies on the cardiovascular system for oxygen transport.
External Respiration: Gas exchange between air and blood in the lungs.
Transport: Movement of gases to/from lungs and tissues.
Internal Respiration: Gas exchange between blood and tissue fluid.
Nasal Cavities:
Structure: Divided by a septum, lined with mucous membranes to trap particles.
Function: Filtration, warming, and moisture of air.
Pharynx:
Structure: Funnel-shaped cavity connecting nasal and oral cavities.
Function: Defense against pathogens through tonsils.
Larynx:
Structure: Contains vocal cords, glottis, and the Adam's apple.
Function: Sound production; directs air into trachea.
Trachea:
Structure: Reinforced by C-shaped cartilaginous rings, lined with ciliated epithelium.
Function: Transports air; cilia sweep mucus and debris upward.
Bronchial Tree:
Structure: Primary bronchi branch into smaller bronchioles.
Function: Airways for air to travel into lungs.
Lungs:
Structure: Right lung has three lobes, left lung has two, due to heart position.
Function: Site of gas exchange facilitated by alveoli.
Structure: About 300 million alveoli increased surface area, surrounded by blood capillaries.
Function: Oxygen enters blood, CO2 exits into alveoli for exhalation. Surfactant reduces surface tension to keep alveoli open.
Ventilation Phases:
Inspiration: Active; diaphragm contracts, thoracic cavity expands, lowering alveolar pressure, allowing air to flow in.
Expiration: Passive; diaphragm relaxes, ribs move down and inward, air flows out due to increased pressure.
Boyle's Law: Pressure of a gas decreases as volume increases and vice versa, this governs ventilation.
Nervous System: The brain’s respiratory control center sends signals for breathing; can be modified voluntarily (e.g., speaking).
Chemical Control: Chemoreceptors monitor CO2 levels and pH in blood, adjusting the rate and depth of breathing to maintain homeostasis.
External Respiration: O2 from alveoli to capillaries; CO2 from blood to alveoli.
Internal Respiration: O2 from blood to tissues; CO2 from tissues into blood.
Important Enzymes: Carbonic anhydrase assists in CO2 transport in blood.
Upper Respiratory Infections: Include colds, sinusitis, tonsillitis, laryngitis.
Lower Respiratory Disorders: Include bronchitis, pneumonia, asthma, emphysema, and lung cancer.
Smoking leads to significant respiratory issues, reducing lung function and capacity.