Respiratory system Flashcards
what are the functions of the respiratory tract
-air conduction: conducts air to the lungs
-air filtration: filters out dust, pathogens, and other particles
-humidification: adds moisture to the air
-gas exchange: facilitates the exchange of oxygen and carbon dioxide in the alveoli.
what is the inspired air
air inhaled into the lungs during the process of breathing, this air consists of nitrogen (78%), oxygen(21%), carbon dioxide(0.03%) and trace gases.
what changes during inhalation
-humidification: inspired air is humidified in the nasal passage and upper respiratory tract.
-warming: air is warmed to body temperature as it travels through the respiratory tract.
-filtering: nasal hair, mucus and cilia filter out dust, pathogens and other particles.
what is expired air
air exhaled from the lungs during the process of breathing out.
composed of: oxygen(16% lower than inspired air), carbon dioxide (4% higher than inspired air), nitrogen (78% same as inspired air) and small gases.
what changes during exhalation
-CO2 loading: carbon dioxide is produced by cellular metabolism and is transported to the lungs.
-water vapour: air is saturated with water vapour increasing its humidity.
-temperature: air is cooled as it moves through the respiratory tract.
what is the tidal volume
amount of air inhaled or exhaled during a normal, quiet breath. (mL or L). (approx 500mL, lower for children and infants).
what makes tidal volume important
-breathing efficiency
-assessment of respiratory function
-factors influencing tidal volume
-body size and composition
-age
-respiratory rate
-health conditions
what is the upper respiratory tract consisted off and what are their functions
-nose and naval cavity: warm, humidifies and filters air.
-pharynx (throat): passageway for air and food.
-larynx (voice box): contains the vocal cords and is involved in sound production.
what is the lower respiratory tract consisted off and what are their functions
-trachea (windpipe): conducts air to the bronchi; has cartilage rings for support.
-bronchi: two main branches (right and left) leading to each lung, further dividing into smaller bronchi.
-bronchioles: smaller airways branching from the bronchi, ending in alveoli.
-alveoli: tiny air sacs where gas exchange occurs, surrounded by capillaries.
what are the functions of the nose
-air filtration
-air warming and humidification
-sense of smell
-resonance of voice
what are the functions of the mouth (oral cavity)
-digestion (mechanical and chemical)
-breathing
-speech
-taste
-immune defence.
what are the functions of the pharynx
-air passage
-food passage
-immunological role
-speech
what are the functions of the larynx
-airway protection
-voice production
-air passage
-cough reflex
what are the functions of the trachea
-air conduction
-air filtration
-cough reflex
what are the functions of the pleura (thin layer of tissue that covers the lungs)
-lubrication
-pressure regulator
what are the functions of the bronchi
-air distribution
-air filtration
-regulation of airflow
what are the functions of the bronchioles
-air distribution
-regulation of airflow
-gas exchange
what are the functions of the alveolar ducts
-air transport
-gas exchange
-regulation of airflow
what are the functions of the alveoli
-gas exchange (oxygen transfer and carbon dioxide removal)
-surfactant production
-maintenance of gas exchange surface
what are the functions of the bronchial arteries
supplying oxygenated blood to the lungs, these branch off from the aorta and provide oxygenated blood to the lung tissue, including the bronchi, connective tissue and pleura.
2 supplying the left lung
1 supplying the right lung
what are the mechanics of inspiration
-muscle action: diaphragm contracts and moves downwards and external intercostal muscles contract to lift the ribs and expand the thoracic cavity laterally.
-pressure changes: intrapulmonary pressure, decreases below atmospheric pressure, creating a pressure gradient that allows air to flow into the lungs. intrapleural pressure, more negative due to expansion of thoracic cavity assisting lung expansion.
-lung expansion: increases thoracic volume.
what are the mechanics of expiration
-diaphragm relaxes and moves upwards.
-internal intercostal muscles: pulls ribs downwards and inward, decreasing thoracic volume.
-intrapulmonary pressure increases bone atmospheric pressure due to the decrease in thoracic volume.
-intrapleural pressure: returns to normal negative value as thoracic cavity decreases in volume.
-lung compression: decrease in thoracic volume leads to lung compression, pushing air out of the alveoli’s and into the atmosphere.
what is quiet breathing
-inspiration: passive, driven by the contraction of the diaphragm and external intercostals.
-expiration: Typically, passive during quiet breathing due to elastic recoil of the lungs and chest wall.
what is forced breathing
-inspiration: Involves additional muscles such as the sternocleidomastoid and scalene muscles to increase thoracic volume further.
-expiration: Can be active, involving abdominal muscles and internal intercostals to force air out more rapidly.
what are the functions of the diaphragm and intercostal muscles
-external intercostal muscles: elevate the ribs and expand the thoracic cavity during inspiration.
-internal intercostal muscles: depress the ribs and decrease the thoracic cavity volume during forced expiration.
what are they main steps of gas exchange
1-oxygen transport to alveoli
2-diffusion of oxygen
3-carbon dioxide transport to alveoli
4-diffusion of carbon dioxide
what are the mechanisms of gas exchange
oxygen transport:
-diffusion: from alveoli to capillaries and binding to haemoglobin.
carbon dioxide transport:
-diffusion: from capillaries to alveoli and exhalation.
what factors affect gas exchange
-surface area
-membrane thickness
-partial pressure gradients
what are respiratory centres and what are the key respiratory centres
Respiratory centres are specialised areas in the brain responsible for regulating and controlling the rate and depth of breathing.
key respiratory centres:
-medullary respiratory centres (in medulla oblongata)
-pontine respiratory centres (in brainstem)
how is breathing controlled
-voluntary control: cerebral cortex
-automatic control: chemoreceptors
-reflexive control: lung stretch receptors and other reflexes.
what is the respiratory rate and what are the normal values
number of breaths taken per minute
normal values:
-adults: 12-20 breaths per min
-children: 20-30 breaths per min
-infants: 30-60 breaths per min
what factors influence breathing
physiological factors:
-activity level
-age
-body temperature
chemical factors
-blood gas levels
-blood pH levels
emotional factors
-stress and anxiety
-pain
environmental factors
-attitude
-temperature
medical conditions
-respiratory conditions
-cardiac conditions
what is respiratory arrest and what are the effects and consequences
condition where breathing completely stops
-immediate effects: anoxia and loss of consciousness
-systemic effects: cardiac arrest and organ failure
-long term consequences: brain damage and permanent disability.
what are the causes of respiratory arrest
-obstructive: blockage in the airway
-central: failure of the respiratory centres in the brainstem to send signals
-neuromuscular; impairment of the muscles involved in breathing
-respiratory muscle fatigue: exhaustion of respiratory muscles due to prolonged efforts to breathe
what are the initial responses of respiratory arrest
-hypercapnia; accumulation of carbon dioxide in the blood due to cessation of ventilation.
-hypoxemia: rapid decline in blood oxygen levels
-increased heart rate: initial attempt to compensate for low oxygen levels
-vasoconstriction: redistribution of blood flow to vital organs.
what is asthma
inflammation and narrowing of the airways leading to difficulty in breathing and characterised by expiratory wheeze.
pathophysiology:
-inflammation: chronic inflammation of bronchial mucosa.
-bronchoconstriction: tightening of the muscles around the airways
-hyperresponsiveness: increased sensitivity of the airways to various stimuli
-mucus production: excess mucus secretion that can obstruct airways.
what is bronchitis
inflammation of the bronchial tubes which carry air to and from the lungs
pathophysiology:
-inflammation; swelling and irritation of the bronchial tubes
-mucus production: increased mucus secretion, leading to obstruction
-airflow limitation: difficulty of moving air inland out of the lungs due to music and inflammation
what is emphysema
chronic lung condition characterized by the destruction of the alveoli (air sacs) in the lungs, leading to impaired respiratory function.
pathophysiology:
-Alveolar Damage: The walls of the alveoli break down, reducing the surface area for gas exchange.
-Loss of Elasticity: The lung tissues lose their elasticity, causing air to become trapped in the alveoli.
-Airway Collapse: Small airways collapse during exhalation, further trapping air in the lungs.
-Impaired Gas Exchange: Reduced oxygen (O₂) absorption and carbon dioxide (CO₂) elimination due to alveolar destruction.
what is COPD (chronic obstructive pulmonary disease)
progressive lung disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities.
pathophysiology:
-Airflow Limitation: Due to a combination of small airway disease (e.g., chronic bronchitis) and parenchymal destruction (e.g., emphyse
-Inflammation: Chronic inflammation causes structural changes and narrowing of the small airways.
-Mucus Hypersecretion: Excessive mucus production blocks the airways.
-Alveolar Destruction: Loss of alveolar walls and capillary beds reduces the surface area for gas exchange.
what is obstructive shock
Obstructive shock is a form of shock that occurs due to physical obstruction of the great vessels or the heart itself, leading to reduced cardiac output and inadequate tissue perfusion.
Significance: It is a life-threatening condition requiring prompt recognition and treatment.
what is the pathophysiology of obstructive shock
Mechanical Obstruction: Physical blockage impedes blood flow through the circulatory system.
Decreased Preload or Increased Afterload: Obstructions can prevent the heart from filling properly (decreased preload) or cause resistance to blood being pumped out (increased afterload).
Reduced Cardiac Output: The heart cannot pump sufficient blood to meet the body’s needs.
Tissue Hypoperfusion: Inadequate blood flow leads to cellular hypoxia and metabolic acidosis.
what are the symptoms of obstructive shock
Hypotension: Low blood pressure due to impaired cardiac output.
Tachycardia: Rapid heart rate as a compensatory mechanism.
Dyspnoea: Difficulty breathing due to inadequate blood flow and oxygenation.
Chest Pain: Varies based on the underlying cause.
Altered Mental Status: Confusion or loss of consciousness due to poor cerebral perfusion.
+/- Signs of Right Heart Failure: Jugular venous distention, peripheral oedema.
what are the symptoms of obstructive shock
RR: increases
HR: increases
SPO2: decreases
BP: decreases
CRT: up or down
Temp: no change
mental status: up or down.
