Respiratory system Flashcards
What are the functions of the respiratory system? (4)
Exchange of gas between atmosphere and blood: uptake O2 and release CO2, respiratory area about 70 sq. m
Filtration, temperature regulation, humification
Olfaction
Production of sound
What are the structures of the respiratory system?
Nose, nasal cavity, pharynx, larynx, trachea, smaller airways, diaphragm
What is the structural organization of the respiratory system?
Upper and lower
Conducting portion
Respiratory portion
What are the structures of the upper respiratory system? (9)
External nares (1 larger than the other)
Nasal vestibule
Conchae: lateral nasal wall, 3 cartilaginous/bony projections, called turbinates when covered with mucus because they create air turbulence to warm it
Internal nares, nasopharynx
Eustachian tube: connects nasopharynx to inner ear, tube blocked during cold makes ears feel full, why your ears pop
Oropharynx
Epiglottis: posterior or tongue, sorts food and air
Laryngopharynx
What are the steps in swallowing? (4)
- Tongue forces compacted bolus into oropharynx (raise tongue to roof and direct posterior)
- Laryngeal movement folds epiglottis, pharyngeal muscles push bolus into esophagus via 2 muscles (levator and tensor) which elevates soft palate and tenses it so food does not go into the nose
Step 3: Bolus moves long esophagus, larynx returns to normal position
Palatine tonsils and pharyngeal tonsils
What does the lower respiratory system contain?
Bronchi, lungs, wtc
What is the root of the lung called and what does it do?
Called the Hilum
Site where blood vessels, nerves, lymphatics and airways enter and leave the lung
What are the features on the right lung?
Superior lobe
Inferior lobe
Middle lobe
Apex/base
Oblique fissure (separates inferior and middle)
Horizontal fissure (separates superior and middle)
What are the features of the left lung?
Superior lobe
Inferior lobe
Apex/ base
Lingua (tongue like invagination from heart)
Cardiac notch (impression from heart because 2/3 of heart sits on the left side)
Oblique fissure (separates superior and inferior lobes)
What colour is the artery and vein in the lung?
Artery is blue because its bringing deoxygenated blood to the lungs from the heart
Vein is red because it carries the oxygenated blood back to the heart to be distributed
What are the two pleura?
Parietal pleura: covers body wall, somatic innervation
Viscera pleura: covers lung, autonomic innervation
What is the space between the pleura called? What is its function?
Pleural cavity, space between visceral and parietal pleura
Both serous membranes, secrete serous fluid from both membranes and allows the lungs to expand without friction
What are the major airways? (6)
Trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles
How many secondary and tertiary bronchi are in each lung? How many bronchioles?
2 secondary in each lung
Right lung has usually 10 tertiary bronchi
Left lung usually 8-10 in left lung
14 bronchioles
What is found on the trachea? Why is it arranged like this?
Cartilage rings, they line the anterior/lateral portion of the trachea, prevents collapse of trachea due to negative pressure generated while breathing
Posterior wall has smooth muscle and contacts the esophagus, therefore it can expand and accommodate large bolus for smooth passage down.
What does the cartilage look like as you are getting into the lung?
Rings become less so in the secondary bronchi, and the smaller bronchi have patchy cartilage and there are no cartilage in bronchioles and have lots of smooth muscle instead
What are the four components of the terminal airway?
Terminal bronchioles (conducting)
Respiratory bronchioles (begin respiration)
Alveolar ducts
Alveolar sacs (bulk of gas exchange)
What are the two types of airways? What do they do?
Conducting: only conduct air, contains everything up to the respiratory bronchioles
Respiratory: both conduct and respire, includes the respiratory bronchioles and alveolar duct/sac
What are the three parts of the airway wall and what are their functions?
Cartilage: found in larger airways, helps keep airways open
Smooth muscle: predominates in smaller airways, controls diameter of airway and constriction reduces flow
Elastic fibers: predominate in smaller airways and respiratory portion, elastic recoil provides force for expiration
What is involved in an asthma attack? (4)
Smooth muscle in wall of bronchioles contract
Contraction caused by: parasympathetic stimulation, mediators of allergic reactions (histamine)
Muscle contraction reduces airflow
Bronchioles most numerous airways, thus provides greatest resistance
What is involved in emphysema? (5)
Reduced ability to expire air from lungs
Due to breakdown of alveolar walls (produces abnormally large air spaces)
Lowered surface area for gas exchange (reduced respiratory efficiency)
Reduced elastic recoil (due to loss of elastic fibers)
Causes: smoking, pollution and dust
What are the characteristics of the respiratory epithelium?
Pseudostratified epithelium (columnar)
Found in nasal cavity, nasopharynx, large airways
Mucus layer floats on serous (watery) layer secreted by goblet cell and sticky thus trapping debris
What is the differences in respiratory epithelium as you move through the respiratory tract?
Pseudostratified in the large tubes
Stratified squamous non-keratinized in oropharynx
Gradually becomes simple in smaller tubes (simple columnar, simple cuboidal, simple squamous)
What structures are contained within the alveolar wall?
Endothelial cells, basal lamina, capillary on either side of them, alveolar epithelium cell and air space
O2 must cross 5 plasma membranes to pass from air space into a red blood cell
What do Type II Alveolar cells do?
Also called surfactant cells and they secrete surfactant
Surfactant lowers surface tension of alveolar fluid
Prevents alveolar walls from sticking together and collapsing
Especially important for kids because their respiratory systems are not fully developed
What is respiratory distress syndrome? (5)
Occurs in children born prematurely (24 weeks), sometimes use bovine surfactant instead
Type II alveolar cells not yet active
Lack surfactant
Alveoli fail to inflate properly
Insufficient oxygenation of blood
What are alveolar macrophages and what do they do? (6)
Cleaning cells
Ingest debris in alveoli
Enter airways
Become trapped in mucus sheets
Carries towards pharynx by ciliary action
Expectorated or swallowed
What is the blood supply to the alveoli like?
Pulmonary artery follows airway exactly, with same branching pattern down to alveolar capillaries
Pulmonary vein takes fastest path back to the heart and each alveoli has its own capillary bed surrounding it
What are the 3 types of blood vessels in the respiratory system? What do they do?
Pulmonary arteries: travel with airways and branch with airways, carry deO2 blood
Pulmonary veins: travel in interlobular connective tissue and carry oxygenated blood
Lymphatics: travel in interlobular connective tissue
How do alveolar capillaries associate with the alveoli?
They wrap around, each alveoli has its own capillary bed surrounding it for gas exchange , as well as elastic fibres
What are the muscles of inhalation when doing forced breathing? What do they do? (3)
Pectoralis minor: ribs 3-5, move thoracic cage out
Scalenes: lift upper ribs (1 and 2)
Sternocleidomastoid: elevates sternum
What are the muscles of inhalation during quiet breathing? What do they do? (2)
External intercostals: lift ribs superiorly and move sternum anterior, increase volume of thoracic space and decrease pressure
Diaphragm: flattens when inhaling to increase thoracic volume and decrease pressure and increase vertical diameter or thoracic cavity
What happens to the sternum and ribs when you inhale?
They elevate
What are the muscles of exhalation during forced and quiet breathing?
Internal intercostals: pull rib above and compress thoracic cage
Abdominal muscles: move ribs inferiorly, compress viscera and move diaphragm superiorly
What provides the movement for quiet breathing exhalation?
Elastic recoil of lung tissue and thoracic wall
