Respiratory System Flashcards

Overview

• References: Tortora, G. J. & Derrickson, B. (2014). Principles of Anatomy and Physiology, 14th Ed. John Wiley and Sons, Inc. Singapore. Chp 23 p. 840 – 885.

Learning Outcomes

• Understand the functions of the respiratory system.

• Describe the anatomy of the respiratory system.

Functions of the Respiratory System

• Gas exchange: Exchange of oxygen (O2) and carbon dioxide (CO2) between atmospheric air and blood. This process occurs in the alveoli of the lungs, where oxygen diffuses into the bloodstream and carbon dioxide diffuses out.

• Body fluid pH regulation: Regulation of blood carbon dioxide (CO2) concentration. The respiratory system helps maintain pH balance by adjusting the rate and depth of breathing, which affects CO2 levels in the blood.

• Sense of smell: Olfactory function. Specialized olfactory receptors in the nasal cavity detect odor molecules in the air.

• Voice production: Phonation enabled by airflow. Air passing through the larynx vibrates the vocal cords, producing sound.

• Air conditioning: Filtering, warming, and moistening inspired air. The respiratory system warms and humidifies incoming air to protect the delicate tissues of the lungs.

Anatomy of the Respiratory System

• Upper respiratory tract:

  • Nose: The external structure of the nose leads into the nasal cavity.

  • Nasal cavity: Located between the external nose and pharynx; responsible for warming, moistening, and filtering air.

  • Pharynx: Also known as the throat, it is a passageway for both air and food.

• Lower respiratory tract:

  • Larynx: Connects the pharynx to the trachea and contains the vocal cords.

  • Trachea: A tubular structure that extends from the larynx to the bronchi.

  • Bronchi: The trachea divides into the right and left primary bronchi, which enter the lungs.

  • Lungs: The main organs of respiration, responsible for gas exchange.

Upper Respiratory Tract

• Components: Nose, nasal cavity, pharynx.

Nose

• Start of the respiratory system.

• External portion

  • The visible structure of the nose.

• Internal portion

  • Nasal cavity – Located between the external nose & pharynx.

• Functions of internal structures:

  • Air Preparation: Warms, moistens, and filters incoming air.

  • Olfaction: Olfactory stimuli are detected.

  • Speech Modification: Modifies speech vibrations.

Pharynx (Throat)

• Passageway: Serves as a passageway for air, food, and drink.

• Structure: Wall composed of skeletal muscle with a mucous membrane lining.

Lower Respiratory Tract

• Components: Larynx, trachea, bronchi, lungs.

Larynx (Voice Box)

• Connection: Connects the pharynx to the trachea.

• Location: Lies anteriorly to the oesophagus.

• Epiglottis: Prevents food and drink from entering the larynx during swallowing.

• Vocal Cords: Produce sound via vibration.

Trachea (Windpipe)

• Connection: Connects the larynx to the bronchi.

• Cartilage Rings: Incomplete rings of (C-shaped) cartilage prevent the trachea from collapsing during inspiration.

• Primary Bronchi (T5): The trachea divides into the primary bronchi at the level of the fifth thoracic vertebra (T5).

  • Rings of C-shaped cartilage prevent the bronchi from collapsing.

• Secondary & Tertiary Bronchi:

  • Connect the primary bronchi to the bronchioles.

  • Rings of cartilage are replaced by strips of cartilage.

Bronchioles

• Connection: Bronchioles connect the tertiary bronchi to the alveoli.

• Smooth Muscle: Cartilage is replaced by smooth muscle, allowing for constriction and dilation of these airways.

• Cilia: Cilia are absent in the smallest airways (terminal bronchioles).

• Terminal Bronchioles: Subdivide into microscopic respiratory bronchioles.

Alveoli

• Gas exchange: Very large surface area for gas exchange.

• Capillaries: A rich supply of blood capillaries surrounds each alveolus.

• Alveolar Macrophages: Remove particles from the alveoli.

• Surfactant: Some alveolar cells secrete a fluid that keeps the alveoli moist and contains surfactant.

Lungs

• Shape & Arrangement: The lungs are paired cone-shaped organs separated by the heart.

• Lobes:

  • The right lung has three lobes.

  • The left lung has two lobes.

Sites of Gas Exchange

• Terminal bronchioles.

• Alveolar ducts.

• Alveolar sacs.

• Alveoli.

Pleura

• Pleural membrane encloses and protects each lung:

  • Parietal pleura.

  • Pleural cavity.

  • Visceral pleura.

• Serous membrane.