Respiratory System PDF

**Function of the Respiratory System** Oversees gas exchanges (oxygen and carbon dioxide) between the blood and external environment Exchange of gases takes place within the lungs in the alveoli (only site of gas exchange, other structures passageways Passageways to the lungs purify, warm,...

**Function of the Respiratory System** Oversees gas exchanges (oxygen and carbon dioxide) between the blood and external environment Exchange of gases takes place within the lungs in the alveoli (only site of gas exchange, other structures passageways Passageways to the lungs purify, warm, and humidify the incoming air Shares responsibility with cardiovascular system **Organs of the Respiratory System** - Nose - Pharynx - Larynx - Trachea - Bronchi - Lungs -- alveoli  **The Nose** The only externally visible part of the respiratory system Air enters the nose through the external nares (nostrils) The interior of the nose consists of a nasal cavity divided by a nasal septum **Anatomy of the Nasal Cavity** Olfactory receptors are located in the mucosa on the superior surface The rest of the cavity is lined with respiratory mucosa Moistens air Traps incoming foreign particles  **Anatomy of the Nasal Cavity** -- Lateral walls have projections called conchae - Increases surface area - Increases air turbulence within the nasal cavity --The nasal cavity is separated from the oral cavity by the palate - Anterior hard palate (bone) **Paranal Sinuses** Cavities within bones surrounding the nasal cavity - Frontal bone - Sphenoid bone - Ethmoid bone - Maxillary bone **Functions of the Paranasal Sinuses** - Lighten the skull - Act as resonance chambers for speech - Produce mucus that drains into the nasal cavity **Pharynx (Throat)**  **Pharynx (Throat)** **Pharynx (Throat)** Muscular passage from nasal cavity to larynx Three regions of the pharynx - Nasopharynx - superior region behind nasal cavity - Oropharynx - middle region behind mouth - Laryngopharynx - inferior region attached to larynx The oropharynx and laryngopharynx are common passageways for air and food **Structures of the Pharynx** Auditory tubes enter the nasopharynx Tonsils of the pharynx - Pharyngeal tonsil (adenoids) in the nasopharynx - Palatine tonsils in the oropharynx - Lingual tonsils at the base of the tongue **Larynx (Voice Box)** Routes air and food into proper channels Plays a role in speech Made of eight rigid hyaline cartilages and a spoon-shaped flap of elastic cartilage (epiglottis)  **Structures of the Larynx** Thyroid cartilage - Largest hyaline cartilage - Protrudes anteriorly (Adam\'s apple) Epiglottis - Superior opening of the larynx - Routes food to the larynx and air toward the trachea **Structures of the Larynx** Vocal cords (vocal folds) - Vibrate with expelled air to create sound (speech) Glottis - opening between vocal cords  **Trachea (Windpipe)** Connects larynx with bronchi Lined with ciliated mucosa - Beat continuously in the opposite direction of incoming air - Expel mucus loaded with dust and other debris away from lungs Walls are reinforced with C-shaped hyaline cartilage **Primary Bronchi** Formed by division of the trachea Enters the lung at the hilus (medial depression) Right bronchus is wider, shorter, and straighter than left Bronchi subdivide into smaller and smaller branches **Lungs** Occupy most of the thoracic cavity Apex is near the clavicle (superior portion) Base rests on the diaphragm (inferior portion) Each lung is divided into lobes by fissures - Left lung - two lobes - Right lung - three lobes **Coverings of the Lungs** Pulmonary (visceral) pleura covers the lung surface Parietal pleura lines the walls of the thoracic cavity Pleural fluid fills the area between layers of pleura to allow gliding **Respiratory Tree Divisions** - Primary bronchi - Secondary bronchi - Tertiary bronchi - Bronchioli - Terminal bronchioli **Respiratory Tree Divisions** **Bronchioles** - Smallest branches of the bronchi - All but the smallest branches have reinforcing cartilage - Terminal bronchioles end in alveoli **Respiratory Zone** Structures - Respiratory bronchioli - Alveolar duct - Alveoli Site of gas exchange **Alveoli** Structure of alveoli - Alveolar duct - Alveolar sac - Alveolus - Gas exchange **Respiratory Membrane (Air-Blood Barrier)** Thin squamous epithelial layer lining alveolar walls Pulmonary capillaries cover external surfaces of alveoli