resp 1 Flashcards
what are the four primary functions of the respiratory system?
- exchange of gases between the atmosphere and blood
- homeostatic regulation of body pH
- protection from inhaled pathogens and irritating substances
- vocalization
air exchange occurs by _______________
BULK FLOW and follows many principles that govern bulk flow through the CV system
how is bulk flow similar between the CVS and air exchange?
-flow occurs from region of high pressure to low pressure
-muscular pump creates the pressure gradients
-resistance is primarily influenced by diameter of tubes through which air is flowing
what does cellular respiration require?
-coordination between the respiratory system and CVS
what is external respiration?
-the movement of gases between the environment and the cells within the body
-four step process
what is the four step process of external respiration?
-the respiratory and circulatory systems coordinate to move oxygen and CO2 between the atmosphere and the cells
what is cellular respiration?
what are structures involved in ventilation and gas exchange?
-conducting system or airways
-alveoli
-the bones and muscles of the thorax (chest cavity)
what are lungs?
-composed of light spongy tissue whose volume is occupied mostly by air-filled spaces
-right lung is slightly larger than left (cardiac notch)
each lung is surrounded by:
a double-walled pleural sac
-one layer is connected to the outside surface of the lungs (visceral pleura) and the other to the inside surface of the thoracic cavity (parietal pleura)
what are the functions of the pleural sac?
-creates moist slippery surface
-holds lungs tight to thoracic wall
how do airways connect lungs to the external environment?
-air enters the pharynx through the nasal cavity and/or mouth
-from the pharynx air flows through the larynx (vocal cords) to the trachea (wind pipe)
-trachea is a semi-flexible tube held open with 15-20 cartilage rings
what is the branching of the airways?
follows similar branching of CV system, increase in total C.S area
-velocity of air flow inversely proportional to total cross sectional area V=Q/A
what do the upper airways and bronchi do?
plays an important role in conditioning air before it reaches the alveoli:
-warming air to body temperature
-adding water vapor
-filtering out foreign material
why are the processes of the upper airways and bronchi more efficient with nose breathing?
-nasal cavity: large surface area, rich blood supply and nasal hair
-shape of nasal airway tends to cause particles to embed in mucus in the back of the pharynx and slide down to the esophagus
where is air filtered?
-the trachea and bronchi
how do cilia and epithelial cells do?
-saline is produced by the epithelial cells and overtop of the saline is a layer of mucus produced by goblet cells
-mucus contains immunoglobulins
-the epithelial cells also contain cilia which push the mucus towards the pharynx (mucocilliary escalator)
saline is necessary for _____________________ function
MUCOCILLARY ESCALATOR
-cilia move the saline lather which pulls the mucus layer upward towards the pharynx
-without the saline layer, cilia would become embedded in thick mucus and unable to move
what is cystic fibrosis caused by?
-caused by an autosomal recessive mutation in the gene producing CFTR (cystic fibrosis transmembrane conductance regulator)
-reduced production of saline
-mucus cannot be cleared properly allowing bacteria to colonize in the airways leading to reoccurring lung infections
-also affects pancreas (names due to formation of cysts and fibrosis of pancreas)
what are alveoli?
-the site of gas exchange
-300-600 million alveoli in an adult respiratory system
-clustered at the ends of bronchioles
-heavily vascularized (80-90% alveoli covered) and huge surface area optimal for gas exchange
what is the graph of the structure of alveolar structure?
what is the low pressure in the pulmonary circuit?
-low pressure due to low resistance (shorter length circuit, more distensible and larger total cross-sectional area of arterioles)
-low pressure means minimal filtration of fluid out of capillaries but there are lymphatics to remove any fluid that does get filtered and keep the diffusion distance to a minimum
what is pulmonary circulation?
high-flow, low pressure
-contains about 0.5 L or 10% of total blood volume (75ml in capillaries)
-rate of blood flow through the lungs is very high, CO is equal in the pulmonary and systemic circuit
-even though it has a high flow rate, it is a low pressure circuit
