Respiratory System Quiz

Respiratory System Overview

• The respiratory system is responsible for gas exchange, delivering oxygen to the blood and removing carbon dioxide.
• Key organs include the nose, mouth, pharynx, larynx, trachea, bronchial tree, and lungs.
• The respiratory tract carries air to and from the lungs.

Learning Objectives

• Understanding the organs of the respiratory system
• Describing the function and structure of respiratory organs, including the respiratory membrane
• Defining external and internal respiration processes
• Identifying respiratory volumes such as tidal volume, residual volume, expiratory reserve volume, and inspiratory reserve volume
• Recognizing non-respiratory air movements
• Describing gas exchange and transport mechanisms for CO2 and O2
• Explaining respiratory control mechanisms
• Identifying and describing various respiratory disorders

Respiratory Tract

• The upper respiratory tract includes the nose, mouth, pharynx, and larynx
• The lower respiratory tract includes the trachea, bronchial tree, and lungs

Lung Structure

• Lungs are divided into lobes (2 left, 3 right)
• The hilum is the entry/exit point for structures like pulmonary veins, arteries, and bronchial vessels.

Lung Blood Supply

• Lungs receive deoxygenated blood via pulmonary arteries.
• Oxygenated blood leaves the lungs via pulmonary veins.
• Oxygenated blood is carried from the lungs to the heart

Respiratory functions

• Ventilation (delivery of O2 and removal of CO2 and H2O from the lungs)
• Gas exchange ( the diffusion of O2 into the bloodstream, and the diffusion of CO2 out of the bloodstream)
• Maintaining blood pH ( regulates the acid-base levels in the blood)
• Air preparation (filtering, warming, humidifying inhaled air)
• Vocalization (production of speech)
• Olfaction (smell detection)
• Protection against pathogens (protection of respiratory surfaces from dehydration, temperature changes, and pathogens)

Basis of Respiration

• Inhalation occurs due to a pressure difference from the lungs vs the atmosphere.
• The volume in the lungs increases due to ribcage volume changes from the intercostal muscles and diaphragm lowering
• Lungs move with the chest wall due to the closed cavities

Upper Respiratory Tract- Nasal Cavity

• Nostrils are supported by alar cartilages
• Covered with a mucous membrane (containing lysozyme)
• Function to filter, warm, and moisten inhaled air
• The olfactory mucosa detects odors

Upper Respiratory Tract - Pharynx

• A muscular tube connecting nasal and oral cavities to the esophagus and larynx.
• Subdivisions include nasopharynx, oropharynx, and laryngopharynx.
• Contains tonsils (pharyngeal, palatine, lingual)

Upper Respiratory Tract - Larynx

• The larynx is a cartilaginous structure for airway protection, and voice production.
• Key cartilages include epiglottis, thyroid, and cricoid cartilages
• Contains vocal folds that create sound upon air passing through

Vocal Folds

• Voicing requires adduction of vocal folds
• Air from the lungs forces vocal folds apart for sound

Lower Respiratory Tract - Trachea

• Descends through the thorax and divides into two main bronchi.
• Contains C-shaped cartilages rings (fibroelastic membrane holds them together)
• Lined with a specialized mucous membrane with cilia (beat upwards)

Lower Respiratory Tract - Bronchi

• Similar structure to the trachea, with incomplete cartilage rings
• Travel obliquely to enter the lungs
• Divided into smaller branches (segmental and tertiary bronchioles)
• Terminal bronchioles
• The bronchioles control airflow and distribution.

Lower Respiratory Tract - Alveoli

• Tiny, thin-walled air sacs with rich blood supply
• Gases diffuse across the respiratory membrane
• Covered in surfactant (reduces surface tension to prevent collapse)
• Contain macrophages to kill bacteria

Pleura

• Lungs are covered by a double-layered membrane (visceral and parietal pleura)
• The pleural cavity is the potential space between these layers
• Pleural fluid reduces friction during breathing

Muscles of Inhalation

• Diaphragm (musculofibrous) divides the thorax from the abdomen
• External intercostal muscles are obliquely positioned
• Diaphragm is responsible for 75% and intercostals responsible for 25% of air entering the lungs

Pulmonary Ventilation/Breathing

• Inhalation is when the lungs expand due to decreased pressure from muscle contraction
• Exhalation occurs when the lungs revert back to normal size by the relaxation of the inhalation muscles.

Factors Affecting Pulmonary Ventilation

• Surface tension of alveolar fluid (surfactant)
• Lung compliance (elasticity and surface tension)
• Airway resistance (diameter of airways influences resistance)

Lung Volumes

• Four major pulmonary volumes are tidal volume, expiratory reserve volume, residual volume, and inspiratory reserve volume.
• These volumes make up pulmonary capacities

Non-Respiratory Air Movements

• Cough, sneeze, crying, laughing, hiccups, and yawning are different forms of involuntary respiration

Respiratory Membranes

• Exchange of oxygen and carbon dioxide within alveolar wall/capillary wall (thin, moist, permeable surface)
• External Respiration: air in the alveoli and blood in the pulmonary circulation
• Internal Respiration: exchange of oxygen and carbon dioxide between cells and blood in the systemic capillaries

Oxygen Transport

• Oxygen binds to hemoglobin to form oxyhemoglobin.
• Temperature and pH affect hemoglobin's affinity for oxygen.

Control of Respiration

• Respiration is controlled by the respiratory center located in the brainstem (medulla and pons)
• Receptors monitor blood oxygen, carbon dioxide, and pH levels
• Breathing rate varies based on physical activity and metabolic demands

Associated Disorders

• Infectious and inflammatory disorders: common cold, influenza, sinusitis, tonsillitis, pharyngitis, laryngitis, tracheitis, diphtheria, hay fever, etc.
• Obstructive lung disorders: bronchitis, emphysema, asthma, bronchiectasis
• Restrictive disorders: pneumoconiosis, pulmonary toxins, pneumonia, lung infections, TB, lung tumor, bronchial carcinoma, pleural mesothelioma, lung collapse, impaired surfactant function, and pressure collapse
• Pulmonary Embolism