Microanatomy 2 Respiratory Flashcards
what are the two functional components of the respiratory system
- The conducting portion
2. The respiratory portion
what is the function of the conducing system of the respiratory system
- Air transport
- Humidification and temperature regulation
- Filtration and removal of particles
- Antibacterial and immunological defence
- The sense of smell via the olfactory epithelium
- The production of sound
what is the function of the respiratory system of the respiratory system
- where gas exchange takes place
what is the conducting system made up of
- upper and lower respiratory tract
what are the parts that make up the upper respiratory tract
nasal cavity
paranasal sinuses
nasopharynx
larynx
what are the parts of the lower respiratory tract
trachea
bronchi
bronchioles
terminal bronchioles is last part
what does the epiglottis do
– guard the entrance to the trachea and lower airways, functions as the organ of voice
as bronchi divide ..
diameter decreases each time
what are the two types of mucosa present in the respiratory tract
mucocillary escalator and mucosa associated lymphoid tissue MALT
what type of epithelium is the respiratory epithelium
ciliated pseudostratified columnar with goblet cells that secrete mucus
what does BALT stand for
bronchus associated lymphoid tissue
what is respiratory epithelium
- This is the epithelium that makes up the upper respiratory tract, trachea and large bronchi
what happens to the respiratory epithelium and goblet cells as the bronchi decrease in size
- it changes from pseudo stratified to ciliated simple columnar and them simple cuboidal epithelium
- there is a decrease in the number of goblet cells
what happens when the respiratory epithelium suffers from abrasion
- The respiratory epithelium is replaced by stratified squamous epithelium
describe what the mucus does
- Secretions from the epithelium, goblet cells and submucosal mucous glands form a viscous fluid layer that overlies the respiratory epithelium
- The secretion traps inhaled particles and microorganisms
what does mucus contain
- Fluid contains mucin, water, ions and antimicrobial substances including immunoglobulin A (IgA) and lysozyme
How does the mucocilliary escalated work
- Inhaled particles, microorganism and epithelium that is fallen of is trapped in the mucus and is moved via ciliary action of the respiratory epithelium towards the pharynx
what is a trachea
- It is a flexible tube made out of fibroelastic tissue and cartilage
what does the properties of a trachea allow them to do
- Properties allow expansion in diameter and extension in length during inspiration and elastic recoil during expiration
what are the layers that make up the respiratory epithelium
- Lamina propria
- submucosa
- c shaped rings of hyaline cartilage
- adventitia
describe the layers that make up the respiratory epithelium
- Respiratory epithelium
- Lamina propria – contains large amount of elastin and aggregates of lymphoid tissue (BALT) ; an elastic network separates it from the submucosa – has lymphocytes in it
- Submucosa – contains seromucous glands with mucus and serous fluid secreting components
- C – shaped rings of hyaline cartilage – provide a semirigid supporting skeleton outside the submucosa to prevent collapse of the airway during inspiration
- Adventitia – outermost fibroelastic connective tissue layer
describe the structure of the bronchi
- Same structure as the trachea but changes when it decreases in size
As size decreases
- Respiratory epithelium not the as tall and contains fewer goblet cells
- Lamina propria has more elastic tissue
- A muscularis mucosae begins to take shape between the lamina propria and submucosa
- Fewer submucosal, seromucous glands
- Cartilage is in plates rather than rings
what happens to the structure of the bronchi by the time it divides into segmental bronchi
- The respiratory epithelium is ciliated simple columnar rather than pseudostratified
- Muscularis mucosae is prominent
- Few cartilage plates and few seromucous glands
what are the bronchioles
smallest conducting airways
what is the diameter of the bronchioles
less than 1mm
describe the structure of the bronchioles
- have a few Clara cells
- have a prominent muscular mucosal
- no cartilage
- no seromucous glands
describe the role of the Clara cells
- they are secretory cells whose function is unclear, - - they have protective roles against the effects of toxins and proteases in addition to role in the management of distal airways fluids
what is the role of the muscular mucosal
- has smooth muscle in it - this controls the flow of air to different portions of the lungs
- smooth muscle is innervated by autonomic nerves, adrenal medullary hormones and local factors
how do the bronchioles stay open
- maintained in an open state by radial traction of elastic fibres in lung tissue
- during inspiration there is distension of air spaces in the lungs which means that the bronchioles are also distended
- expiration is passive due to the recoil of elastic fibres surrounding the air spaces
- bronchioles remain open due to the remaining elastic tension in their walls
- when expiration is forced it compresses the bronchioles
- septa full radially on the bronchiole wall keeping it open even during expiration
what is the air spaces with their walls capped
- Surrounding air spaces with there walls is called the interalveolar septa
what do the capillaries surrounding the lung tissue do
- Surrounding lung tissue contains capillaries for gas exchange and relatively large amounts of elastic tissue
describe the structure of the inter alveolar septa
- adjacent alveoli form inter alveolar septa which consists epithelial lining of the alveoli on each side and a thin layer of loose, highly elastic, connective tissue in between
- loose connective tissue contains an extensive network of pulmonary capillaries, few fibroblasts, some reticular fibres and numerous elastic fibres
- The part of the lung is known as the interstitium and is affected in a number of inflammatory and fibrosing conditions
the respiratory bronchioles are part of ..
both the conducting and respiratory portions
what is a differntial characteristic of respiratory bronchioles
- have alveoli in their walls
what does peak flow do
Peak flow measure the maximum rate of expiration
what causes asthma
- Mucous plugging
- Wall thickening – inflammation, oedema, cell infiltration
- Smooth muscle hypertrophy
- Fibrosis underlying the epithelila basement memrbaen
- Goblet cells hyperplasia and submuscosal gland enlargement
- Increased vascularisation of the wall, epithelial necrosis and inflammatory cell infiltration
asthma is an
obstructive disorder
what does small airway obstruction occur due to
bronchospasm, inflammation and oedema with mucous plugging
what are the respiratory portions of the lungs involved in
directly involved in the transfer of oxygen from the air into the blood and carbon dioxide from the blood into the air
describe the structure of the alveolus
- Thin walls
- Surrounded by a rich network of pulmonary arteries
- spherical
- 250mm in diameter
what is the alveolus
the structural unit of gas exchange
what is the pulmonary or respiratory acinus
- The pulmonary or respiratory acinus is the functional unit of the lung and is defined as all the components involved in respiratory exchange beginning at a first order respiratory bronchiole and ending in its sacs of alveoli
- important in definition of some respiratory diseases where the acinus as a whole is affected
what does the first order repsiratory bronchiole divided into
- First order respiratory bronchiole undergoes further branching and forming ill-defined alveolar ducts whose walls are mainly composed of alveoli and little smooth muscle
describe what the alveolar ducts divide into
- Alveolar ducts terminate in two or three alveolar sacs whose walls are comprised completely of alveoli
what are type I pneumocystes
simple squamous cells that cover most of the alveolar wall
what are type II pneumocystes
cuboidal cells that produce surfactant
what does surfactant do
- reduces surface tension of the fluid lining the alveolar surface
- prevents collapse of alveoli
how does surfactant affect premature babies
- they have a lack of surfactant as it develops late in pregnancy
- they have an insufficient number of type II penumocytes therefore cannot produce it
what do pulmonary macrophages do
defence cells that scavenge particulate matter and microorgansims
what cells are present in the alveolus
type I pneumocytes
type II pneumocytes
pulmonary macrophages
what is the blood brain barrier formed of
- The type I pneumocytes
- A single basement membrane
- Pulmonary capillary endothelium – the single basement membrane is formed by the fusion of basement membranes belonging to the pneumocytes and the pulmonary capillary endothelium
is asthma reversible or irriversible
reversible
name some chronic obstructive diseases
- Emphysema – alveolar wall destruction leading to over inflation
- Chronic bronchitis – productive cough, airway inflammation
- asthma - Bronchial hyperresponsiveness triggered by allergens and infections
different forms of emphysema effect…
different parts of the pulmonary acinus
what happens when you smoke to protease inhibitors
- Lungs are normally protected from proteases released from inflammatory cells by production of protease inhibitors
- With smoking there is inflammatory cell activation causing increased protease activity along with other tissue injury due to toxins in smoke
- Toxins inactivate the protective protease inhibitors such as alpha 1 antitrypsin which leads to their functional deficit unregulated protease activity particular leads to destruction of the interstitial supporting tissue in the lung including its elastic fibres resulting in emphysema
what does a congenital alpha 1 – antitrypsin deficiency lead to
emphysema
