Mindmap

Respiratory Tract

Rana Al-Khayat Year 1 Englisch

Inhalt der Mindmap

Respiratory Tract

UPPER RESPIRATORY TRACT
- air enters the nasal cavity through two openings
  - anterior nares (nostrils)
    - supported by alar cartilage
      - the cartilage is a thin flexible plate situated immediately below the lateral nasal cartilage
        cartilage is bent upon itself in a way that forms the medial and lateral walls of the naris
    - the vestibule is a small space inside the nostrils
      - covered with a dense network of hair which filters out particles that may be present in inhaled air
      - nasal cavity
        receives the Eustachian tube from the inner ear
        walls of nasal cavity are formed by craniofacial skeleton and the septum (that splits the cavity in two) is formed by the vomer bone and an inferior projection of the ethmoid bone
        superior nasal concha
        fold of tissue covering the superior curved plate of bone that hangs down from the ethmoid bone
        space beneath concha in the superior meatus
        middle nasal concha
        fold of tissue that covers the middle-curved plate of bone which hangs down from the ethmoid bone
        space beneath concha is the middle meatus
        inferior nasal concha
        fold of tissue that covers the inferior bone attached to the ethmoid bone
        space beneath concha is the inferior meatus
        mucous membrane
        rich blood supply
        mucosa is a pseudostratified ciliated columnar epithelium containing globet cells
        resting on a lamina propria rich in mucous and serous cells
        secrete mucous rich in lysozyme
        known as the olfactory mucosa
        contains sensory cells that detect odour
        surrounded by and connected to paranasal sinuses
        small irregular spaces filled with air and lined with a mucous membrane, function to lighten the skull and give the voice resonance
        frontal
        ethmoid
        maxillary
        sphenoid
        contains pharyngeal tonsils which protect against inhaled pathogens
        pharynx
        The pharynx is a muscular tube from the base of the skull to the oesophagus (C6). The inner circular muscles of the pharynx are split into the superior pharyngeal constrictor (in the oropharynx), middle pharyngeal constrictor (in the laryngopharynx) and the inferior pharyngeal constrictor (in the laryngopharynx). The inferior pharyngeal constrictor is further split into the superior thyropharyngeus and the inferior circopharyngeus.
        from the nasal cavity, air passes backwards and downwards to the nasopharynx
        pharynx is a musular tube lined with a mucous membrane which joins the nasal and oral cavities to the oesophagus and larynx
        division between nasal cavity and nasopharynx is marked by posterior nares (choanae)
        oropharynx
        sits between the soft palate and the upper body of the epiglottis
        posterior to the oral cavity and tongue
        laryngopharynx
        lies behind the larynx and terminates at the level of the circuit cartilage by becoming continuous with the oesophagus
        LOWER RESPIRATORY TRACT
        larynx
        cartilaginous structure composed of several different cartilage elements
        thyroid cartilage
        largest cartilage of the larynx
        formed by two flat plates that come together anteriorly to join and make the laryngeal prominence (Adam's apple)
        houses and protects the vocal cords
        circoid cartilage
        complete ring of cartilage that forms the inferior border of the larynx
        united with the trachea by the circotracheal ligament
        epiglottis
        thin triangular flap of cartilage located at the entrance of the larynx
        when food is swallowed the epiglottis moves downwards and the larynx moves upwards, blocking off the entrance to the larynx
        food bolus slides down into the oesophagus by passing downwards on either side of the larynx
        food bolus moves into two depressions called the piriform fossae of the laryngopharynx
        two arytanoid cartilages
        two pyramidal cartilages that sit on top of the circoid cartilage and have vocal ligaments attached to them
        the movement of the cartilages tightens or slackens the vocal ligaments which allows us to change the pitch of our voice
        oesophagus
        accessory muscles helps to hold the cartilage together
        functions
        protecting the airways
        closing and sealing the lower respiratory tract
        supports voice production
        voice box
        trachea
        begins at level C6 below the circuit cartilage of the larynx
        descends through the thorax at divides at T4
        carina
        thick, incomplete cartilaginous ring that runs between the two primary bronchi at the bifurcation of the trachea
        directs air into the principle bronchi during respiration
        primary/principle bronchi
        right primary bronchi
        more vertical, shorter and wider
        more likely to be blocked
        left primary bronchi
        more horizontal, longer and thinner
        travel obliquely and enters each lung through the hilum
        mucosa
        muscularis layer (submucosa)
        cartilaginous layer
        adventitia
        binds bronchi to the pulmonary artery and lung parenchyma
        hyaline cartilage becomes reduced in size as the bronchial diameter diminishes
        maintains the appropriate diameter of the airway
        submocosa is composed of mucous-secreting glands and adipose tissue is also present in larger bronchi
        height of epithelial cells and thickness of basal lamina and lamina propria decreases as diameter decreases
        secondary bronchi
        one secondary bronchi for each lung lobe
        the right lung has 3 secondary bronchi
        the left lung has 2 secondary bronchi
        tertiary bronchi
        10 tertiary bronchi in the right lung
        8 tertiary bronchi in the left lung
        do not have c-shaped cartilages but instead they have cartilaginous plates
        bronchioles
        composed of a fibroelastic membrane and smooth muscle and usually do not contain cartilage
        controls the resistance to airflow and distribution of air in the lungs
        branch in turn repeatedly until they form small branches called terminal bronchioles
        devoid of cartilage and largely composed of smooth muscle
        branch into respiratory bronchioles
        alveolar ducts
        alveolar sacs
        alveoli
        type I pneumocytes
        squamous epithelial cells
        have a flat, dark, oval nucleus and a very thin cytoplasm
        primarily involved in gas exchange
        40% of the number of cells in the alveoli but make up 95% of the alveolar surface
        type 2 pneumocytes
        cubodial cells that bulge into the alveolar space
        produces surfactant
        reduces surface tension of the alveoli and prevents them form collapsing on expiration
        progenitor cells that can proliferative to produce both type I and II pneumocystis after lung injury
        makes up 60% of cells in the alveoli but only 5% of the alveolar surface
        terminal dilations of the alveolar ducts and connects to at least two alveoli
        present on the distal end of the respiratory bronchioles
        covered in alveoli
        transition zone concerned with both air conduction and gas exchange
        composed of simple cuboidal epithelium with ciliated and Clara cells
        club cells were originally known as Clara cells
        they are dome-shaped cells with short microvilli
        secretes materials like GAGs, lysozyme and conjugation of the secretory portion of IgA antibodies
        protects bronchiolar epithelium
        also contains a lamina propria, separated circumferential smooth muscle fibres, adventitia and scattered, thin-walled outpocketings called alveoli which extend from the lumen
        start of the respiratory zone
        composed of simple cuboidal epithelium
        also contains brush cells, small granule cells and basal cells
        increased number of Clara cells present
        composed of pseudostratified columnar epithelium which gradually transforms into simple ciliated columnar epithelium
        goblet cells are interspersed among the ciliated cells and extend the full thickness of the epithelium
        brush cells, small granule cells and basal cells are also present
        contains a lamina propria, a relatively thick circumferential layer of smooth muscle and an adventitia
        c-shaped cartilage rings
        united by fibroelastic membrane
        trachealis muscle unites posterior gaps of the cartilages
        mucous membrane
        mucosa
        submucosa
        cartilaginous layer
        adventitia
        binds the trachea to the adjacent structures
        composed of loose connective tissue
        hyaline cartilage
        contains mixed sero-mucous glands
        watery secretions humidify inspired air
        mucous as well as mucous from goblet cells trap particles from air
        epithelia
        tall columnar pseudostratified with cilia and goblet cells
        mucocilliary escalator
        brush cells, small granule cells and basal cells
        brush cells - columnar cells that contain microvilli and function as receptor cells for general sensation as their nerve endings penetrate the basal lamina and come together to form the trigeminal nerve basal cells - reserve population by maintaining individual cell replacement in the epithelium
        lamina propria
        contains elastin which plays a role in the elastic recoil of the trachea during inspiration and expiration
        start of the conducting zone
        also called hypopharynx
        palatine, pharyngeal and lingual tonsils are embedded in the oropharynx
        acute inflammation of the palatine tonsils causes tonsillitis
        formed nodules of lymphatic tissue and function to protect the body against inhaled pathogens
        separated from the oral cavity by soft palate
        oral and nasal cavities are separated by a hard palate of bone and muscle
        formed by projections of the palatine and maxillae bones
        muscular extension of the hard palate and hangs from the back of it which separates the oral cavity from the nasopharynx
Lungs
- Blood supplies of the lungs: - pulmonary circulation brings deoxygenated blood from the heart to the lungs and oxygenated blood from the lungs to the heart and then the rest of the body - bronchial circulation (bronchial artery and vein) brings oxygenated blood to the parenchyma, bronchial circulation is part of the systemic circulation
- situated in the thoracic cavity and connected to the mediastinum by a lung root
- lobes
  - left
    - superior lobe
      - splits into 4-5 segments
    - oblique fissure
    - inferior lobe
      - splits into 4-5 segments
  - right
    - superior lobe
      - splits into 3 segments
    - horizontal fissure
    - middle lobe
      - splits into 2 segments
    - oblique fissure
    - inferior lobe
      - splits into 5 segments
  - further segmented by a connective tissue septum forming pyramid-shaped bronchopulmonary segments
- a primary pulmonary lobule is defined as the lung unit distal to the respiratory bronchioles, it is significantly smaller than an acinus, and is composed of alveolar ducts, alveolar sacs and alveoli
  - one arteriole and an accompanying venue supply/drains one pulmonary lobule
  - respiratory membrane
    - when the capillary wall meets the alveolar wall a respiratory membrane forms
- breathing
  - inspiration
    - initiated by the neurally induced contraction of the diaphragm and the external intercostal muscles
      - activation of the motor neurons in the phrenic nerves that innervate the diaphragm causes it to contract
        dome moves downwards into the abdomen, enlarging the thorax
        simultaneously the activation of the motor neurons of the intercostal nerves to the inspiratory intercostal muscles causes them to contract leading to an upwards and outwards movements of the ribs
        thoracic cavity volume increases
        lungs are stretched and intrapulmonary volume increases
        intrapulmonary pressure drops and air flows down the pressure gradient into the lungs until the intrapulmonary pressure is 0
        expiration
        motor neurons to the diaphragm and inspiratory intercostal muscles decrease their firing rate so that the muscles relax
        diaphragm and intercostal muscles are no longer actively pulled outwards so they start to recoil
        intrapleural pressure becomes less sub atmospheric which decreases the transpulmonary pressure
        the transpulmonary pressure acting to expand the lungs is now smaller than the elastic recoil exerted by the more expanded lungs and the lungs passively recoil to their original dimension
        as the lungs become smaller, the air in the alveoli becomes temporarily compressed so that alveolar pressure exceeds atmospheric pressure
        air flows from the alveoli into the atmosphere passively
  - control of respiration
    - medulla oblongata and pons in the brainstem
      - medullary rhythmicity area (in the medullar oblongata), pneumotaxic and apneustic areas (in the pons)
        mechanosensroy signals are essential for adapting and adjusting breathing - the receptors are located in the smooth muscle of the airway and are stimulated by rapid lung inflation or deflation or oedema and their reflex is to cause a sigh or shortened expiration
        medullary rhythmicity area: regulates breathing rhythm
        can be further divided into the inspiratory area (DRG) and expiratory area (VRG)
        pneumotaxic area: increased firing rate of this area will increase the breathing rate
        apneustic area: transmits stimulatory nerve impulses to the inspiratory area of the MRA, which would cause prolonged deep inhalations if left alone
        cortical control
        voluntary control of the respiratory centre is exerted prdeominantly via the cortical connections that the brain has with the respiratory centre
        nerve impulses from the hypothalamus and limbic system
        chemoreceptors
        central
        clusters of neurones located in the medulla oblongata
        responds to changes in the concentrations of H+ and CO2 in cerebrospinal fluid
        major role in the moment-to moment control of breathing
        peripheral
        located in the aortic arch and carotid bodies
        respond to changes in O2, CO2 and H+ concentrations in the blood by sending nerve impulses to the brain via the vagus (aortic bodies) and glossopharyngeal (carotid bodies) nerves
        signals are sent to the Nucleus Tractus Solitarius (NTS)
        receives information from mechanoreceptors and peripheral chemoceptors, this information is processed in the brainstem by respiratory neurones and generates the rhythm of breathing - the rhythmic signal is sent to the respiratory muscles
        inspiratory and expiratory neurons
        e.g. phrenic nerve exits the spinal cord at C3-5 and goes on to innervate the diaphragm and other nerves go on to innervate the intercostal muscles
        dorsal respiratory group - other respiratory groups are the pontine and ventral respiratory group
        ventral group generates rhythm
        stretch receptors
        located in the lung and chest wall and responds to distension
        Hering-breuer reflex prevents further inspiration
        prevents over-inflation of lungs
        proprioceptors
        monitors the angle of the structure that they innervate
        gives the body means of increasing or decreasing the rate of breathing in response to increased muscle and joint movement
    - respiratory compensation: links blood pH and breathing rate
- fissures are narrow depressions
- pleura
  - the right and left pleura are separated by the mediastinum
  - a serous membrane that surrounds the lung
  - visceral pleura
    - the layer that is superficial to the lungs
  - pleural cavity
    - the space between the visceral and parietal pleura
  - parietal pleura
    - outer layer that connects to the thoracic wall, the mediastinum and the diaphragm
  - produces pleural fluid and creates cavities that separates the major organs
    - pleural fluid is secreted by mesothelial cells from both pleural layers
      - acts to lubricate their surfaces
        reduces friction between the two layers
      - creates surface tension that helps maintain the position of the lungs against the thoracic wall
    - prevents the interference of other organs during organ movement
    - prevents the spread of infection
  - recesses
    - costomediastinal recesses
    - costodiaphragmatic recess
- lung function tests
  - spirometry
    - measures the volume of air that the patient is able to expel from the lungs after maximal inspiration
    - measures forced vital capacity
      - the maximal volume of gas that can be expired from the lungs during a forced expiration from full inspiration
    - measures forced expiratory volume in 1 second
      - maximum volume of gas that can be expired from the lungs during the first second of a forced expiration from full inspiration
        FEV1 decline graph shows that those that quit smoking can/will end up with the same FEV1 levels as those that do not smoke
    - also measures forced mid-expiratory flow (FEF), maximal voluntary ventilation (MVV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV), inspiratory capacity (IC), functional residual capacity (FRC), vital capacity (VC) and total lung capacity (TLC)
  - peak expiratory flow rate
    - subject breathes as hard and as fast as they can into a meter which measures the maximum expiratory flow that can be sustained for a minimum of 10 milliseconds
  - total capacity of the lungs
    - determined using either gas dilution techniques or body plethysmography
  - diffusing capacity of the lungs for carbon monoxide (transfer factor)
    - single breath test that measures the overall gas-exhcange function of the lung
    - diffusion capacity is a measure of of the ability of gas to diffuse from the alveolus
  - arterial blood gas measure
    - measures the arterial oxygen tension (PaO2) and arterial carbon dioxide tension (PaCO2)
  - cardiopulmonary exercise testing
  - respiratory muscle function
Cough reflex
- comes from the autonomic nervous system
- pulmonary irritant mechanoreceptors in the epithelium of the respiratory tract is sensitive to both mechanical and chemical stimuli
  - receptors in the cough reflex are nestled in the epithelial layer and are called "rapidly adapting pulmonary stretch receptors" (RAR). RARs are afferents of the vagus nerve and are activated by dust, smoke, ammonia, oedema etc.
  - bronchi and trachea are sensitive to light touch
- a cough is used to remove foreign matter from the respiratory tract before it reaches the lungs
  - a cough is a protective reflex that rids the airway of any offending material
  - cough receptors are located mainly on the posterior wall of the trachea, pharynx and carina
    - when triggered, impulses travel via the internal laryngeal nerve, which stems from the vagus nerve, and goes to the medulla of the brain
      - the efferent neural pathway transmits signals to the glottis, diaphragm and other major inspiratory/expiratory muscles
        diaphragm and external intercostal muscles contract, air rushes into the lung, epiglottis closes, vocal cords contract to shut the larynx, abdominal muscles contract to accentuate the action of the relaxing diaphragm, vocal cords relax, epiglottis opens (releasing air at over 100mph), bronchi and non-cartilaginous portions of the trachea collapse to form slits through which air is forced
Functions of the respiratory system
- ventilation and gas exchange, regulation of blood pH, air preparation, vocalisation, olfaction, protection and defence

Bilder und Dateien der Mindmap

Informationen

Beschreibung: Year 1 Mindmap am Respiratory Tract, erstellt von Rana Al-Khayat am 04/04/2018.
Erstellt von: Rana Al-Khayat
Aufrufe: 0
Bewertung

Respiratory Tract

Inhalt der Mindmap

Bilder und Dateien der Mindmap

Informationen

Feedback

Wie gefällt dir das neue Design?