lec 1 Flashcards
respiratory + non-respiratory functions of the respiratory system
-oxygen respiration
-remove CO2
-homeostasis
-olfaction
-vocalization
-1st lines of immune defense
-filter blood borne substances
roles of ribcage
-protection- from fraction/injury
-support-muscle attachment + frame
-breathing
explain the anatomy of the lungs
-paired
connected to trachea on left, bronchi on right.
-enclosed in pleurae (2 layers- visceral-lines lungs, and parietal- lines thoracic cavity), which is attached to mediastinum
-bordered by diaphragm
-surrounded by pleural fluid- secreted by the pleura, decreases friction between layers to prevent trauma when breathing + create surface tension that sucks against the thoracic wall
what ensures that the lungs are ‘attached’ to the thoracic wall
-pleural fluid
-pleural pressure (Ppl) (should be slightly neg. (-3/-4 mmHg) to ensure lungs stuck to chest wall, so will move when breathing, which is ESSENTIAL to maintain normal air flow, otherwise deflate)
what causes the negative pleural pressure + why is it important + what is it called when the pleural pressure is NOT neg.
-thoracic recoil out + lung recoil in
- keeps lungs ‘attached’ to thoracic wall, allowing normal airflow
-pneumothorax- when pleural pressure is 0 or +ve
explain the zones of the respiratory system.
-conducting zone (no gas exchange- dead space): includes nose/mouth, trachea, bronchi, bronchioles, terminal bronchioles
-important, as provides conduction of air, warmth, cleanses, and humidifies
- if you breathed directly into the trachea (tracheostomy), causes lung injury/infection
-respiratory zone (gas exchange): includes respiratory bronchioles, alveolar ducts, alveolar sacs
REFER TO ONENOTE
function seperate + together
explain the nose
–opens into the nasal cavity which is separated into left + right by the nasal septum
-conchae- 3 bony projections: superior, middle, and inferior nasal conchae
-meatuses- passage for airflow located beneath each nasal concha
-conchae + meatuses act to increase SA + disrupt airflow, warn + humidify air when inspiring, cool + dry air during expiration, decrease water loss to prevent dehydration
-heat and water exchange in a COUNTER EXCHANGE (move in opposite directions)
-is important for heat + water exchange, filtration
counter vs concurrent flow
counter:
-move in opposite directions
- small gradients
-enables max. exchange for max. efficiency
concurrent:
-move in same direction
gradient for exchange disappears
-not efficient
Heat exchange in the nasal cavity
- surface of nasal cavitiy to incoming air
- nasal blood vessels to air
- mucosal film in nasal cavity
- mucosal film on nostrils inner lining
*note: all via convection
- nostril tissues (via radiation)
how are particles filtered in the nose
-mucous membranes containing sebaceous glands + hair follicles
-nasal hairs
what is the epithelium of the nasal cavity to bronchi, bronchioles, and alveoli
-pseudostratified columnar
-simple columnar to simple cuboidal with fewer ciliated cells
-thin squamous epithelium with no cilia
-respiratory epithelium is thinner as goes deeper down (for diffusion)
explain the lung extracellular matrix
-is a mesh structure made of elastic fibers, proteoglycans, collagens, and adhesion proteins: fibronectins + laminin
-lung structural integrity depends on ECM for mechanical stability, elastic recoil, form basement membrane, regulate growth factors, cell proliferation, differentiation, attachment, migration, shape and protein synthesis
explain collagen as a structural proteins of the ECM + 4 types
-collagen- made of glycoprotein = mostly fibroblasts, essential for strength + integrity
-4 types
*type 1: contributes to lung mechanisms, (stability), and structural framework (note: too much of type 1 : fibrotic lung disease, too stiff)
*type 2: contributes to airway cartilage (95% of total collagen), allows chondrocyte synthesis
*type 3: contributes to lung mechanics + structural framework (same as 1)
*type 4: contributes (strength + funtion of basement membrane)
+ note the type 1:3 ratio determines the resistance of collagen fibres to tearing
explain elastin as a structural protein of the ECM
-made of glycoprotein
-provides alveoli flexibility
helps pull airways open- radial traction
-synthesised by fibroblasts + smooth muscle cells in when embryo (not as adult)
-able to deal wth stretching + recoiling over lifetime
explain proteoglycans as a structual protein of the ECM
- produced by ER + golgi complex
-forms net which collagen fibres are incorporated into
