Compendium 4 Flashcards
What are the functions of the respiratory system
RESPIRATION: breathing in O2 and out CO2
- external respiration: gas exchange between lungs and blood
- internal respiration: gas exchange between blood and tissues
REGULATION OF pH
VOICE PRODUCTION
SMELL
PROTECTION: moves foreign particles away from lungs
What are the divisions of the respiratory system
STRUCTURAL CLASSIFICATION:
- upper respiratory tract: external nose, nasal cavity, threat, pharynx
- lower respiratory tract: trachea, bronchi, lungs
FUNCTIONAL CLASSIFICATION:
- conducting zone: respiratory passages from nose to bronchi–> cleanses, humidifies and warms air so it is clean
- respiratory zone: (in lungs) air exchange between lungs and blood (bronchioles, alveoli ducts, alveoli, microscopic parts)
List structures of the respiratory system
Conducting zone: Nasal cavity Pharynx Larynx Trachea Tracheobronchial tree
Respiratory zone: Alveoli Respiratory membrane Lungs Pleura
Explain the structure of the nose
External nose (bone, cartilage, stratified squamous epithelium) and nasal cavity (starts from nostrils (nares) to choana)
Vestibule: entry to nasal cavity - stratified squamous, contains sweat and sebaceous glands, hair follicles
Hard palate: floor of nasal cavity separating nasal and oral cavity - made of bone
Soft palate: continuance of hard palate - muscular tissue
Uvula: end of soft palate
Septum: separates into left and right halves - anterior is cartilage, posterior is bone
Concha: bony ridges (superior, middle, inferior)
Meatus: passageway under each concha (superior, middle, inferior)
What is the role of the meatus and choncha
Increase SA of nasal cavity creating turbulent air flow so air breathed in comes in to contact with mucous lining and can be filtered
Epithelium of concha and most of nasal cavity is pseudostratified ciliated columnar epithelium - cilia moves trapped particles toward throat to be swallowed, columnar secrete mucus
Explain the pharynx
Also called throat Starts at choana, ends at larynx Opening to both digestive and respiratory system Contains three regions: 1) nasopharynx 2) oropharynx 3) laryngopharynx
Pharynx: explain nasopharynx
Posterior to nasal cavity where soft palate ends
Pseudostratified ciliated columnar epithelium
Eustachian tube opens into nasopharynx from left and rights ears which connects nasopharynx to middle ear allowing pressure in middle ear to equalise with atmospheric pressure and mucus to drain in to nasopharynx to avoid infection
Posterior surface has pharyngeal tonsils (uvula blocks sight of them) – lymphoid tissue
Pharynx: explain oropharynx
Sits at back of oral cavity
Stratified squamous epithelium (protective) – addition of food calls for more layers
Contains palatine tonsils (side of mouth) and lingual tonsils (back of tongue)
Pharynx: explain laryngopharynx
Lies posterior to epiglottis, superior to larynx
Stratified squamous epithelium
Explain larynx
Base of tongue to trachea
Also called voice box
Passageway for air only
Made up of 9 cartilage rings connected via muscles and ligaments:
-6 paired (left and right sides): arytenoid, corniculate (above arytenoid), cuneiform
-3 singular: thyroid (Adams apple), cricoid, epiglottis (up top)
Explain function of larynx
Maintains open passageway for air movement
Directs food info oesophagus away from respiratory tract via epiglottis and vocal folds coming together (vocal folds connected to arytenoid cartilage)
Sound production via vocal folds, when expired air moves past they vibrate and produce sound (tension can vary voice)
Traps debris from entering lungs (cilia)
Explain trachea
Windpipe
Descends from larynx and sits anterior to oesophagus
Has 15-20 c shaped hyaline cartilage rings that support to maintain open pathway for air
On side adjacent to oesophagus there is NO cartilage instead smooth muscle and connective tissue which allows oesophagus to expand when food moves down it without it getting blocked
Dense connective tissue and smooth muscle lie between rings
Trachea lumen (space inside) lined with pseudostratified ciliated columnar epithelium with goblet cells
Explain tracheobronchial tree / bronchial tree
Respiratory passageways from trachea to terminal bronchioles
First structure = CARINA (last piece of cartilage ring slightly larger than other rings) which is sensitive so if foreign matter appears it will initiate a violent coughing fit
Trachea goes off into 2 branches called PRIMARY BRONCHI and enter lungs at HILUM (right is angled more vertically than left so foreign matter enters right bronchi)
Each bronchus divides into SECONDARY/LOBAR BRONCHUS once in the lungs which supply air to the lobes of the lungs (right has 3 lobes and 2 fissures, therefore has 3 lobar bronchus, left has 2 lobes and 1 fissure, therefore has 2 lobar bronchus)
Lobar bronchi divide into TERTIARY/SEGMENTAL BRONCHI which provide air to the bronchopulmonary segments of the lungs which are further subdivisions of the lobes (each bronchus provides to each segments- there are 10 segments in each lung)
Tertiary further divide into bronchioles (smaller than 1mm), smallest as terminal bronchioles (less than 0.5mm)
As trachea branches of there is less cartilage and more smooth muscle, therefore terminal bronchioles= all smooth muscle
Epithelium changes from pseudostratified ciliated columnar to simple ciliated columnar and then to simple ciliated cuboidal
Explain alveoli
Terminal bronchioles don’t contain alveoli but become respiratory bronchioles which do contain alveoli then have alveolar ducts –> alveolar sacs (sit at ends of ducts- can be 2 or 3 and contain clusters of alveoli)
Around 300-500 million alveoli per lung = large SA
Thin, moist walls made of simple squamous epithelium
Explain the respiratory membrane
Elastic fibres cover alveoli allowing them to recoil during breathing
Also covered by blood capillaries (deoxygenated and oxygenated blood back to lungs)
The surface that makes contact with alveoli and capillaries is where gas exchange occurs and is the repository membrane
Alveolus = space where air is breathed in
This alveolus side contains simple squamous epithelium that are called TYPE 1 PNEUMOCYTES (gas exchange, simple diffusion) and contains TYPE 2 PNEUMOCTYES scattered in between which are cuboidal cells that secrete SURFACTANT which reduces surface tension so alveoli don’t stick together when deflated and air is breathed out and prevents alveoli from collapsing
Alveolus side also has macrophages and a basement membrane
Capillary side contains basement membrane, capillary endothelium (simple squamous) and red blood cells
Epithelium allows for rapid diffusion as walls are thin
Explain lungs
No lungs are the same size - presence of heart on left side decreases the size of the left lung, however, right can appear smaller due to liver
Left lung = 2 lobes (superior and inferior) and cardiac notch (indentation) where heart sits
Right lung= 3 lobes (superior, middle, inferior)
Lobes are separated by fissures (indents in tissue)
Hilum on medial surface - entry point for blood and nervous supply, lymphatic vessels and bronchi
Bronchopulmonary segments separated via connective tissue septa – each segment has own artery and vein from individual bronchioles
Explain pleura
Pleural fluid stops friction as lungs and thoracic cavity wall move and visceral and parietal layers slide past each other in ventilation
Also holds pleura together so lungs adhered to thoracic wall - when chest expands to breath in, lungs pulled out and expand as well
If air was introduced in pleural cavity, lung would collapse as pressure of air in cavity pushes against lung tissue (pneumothorax)
List the pathway of air
In nose Nasal cavity Pharynx Larynx Trachea Primary bronchi Secondary bronchi Tertiary bronchi Bronchioles Tertiary bronchioles Respiratory bronchioles Alveoli
List the factors affecting gas exchange
Thickness of respiratory membrane
-thicker (usually due to sickness) = reduced rate movement
Surface area
-diseases such as cancer and emphysema could reduce SA and therefore reduce gas exchange
Diffusion coefficient
-higher diffusion coefficient= faster rate of gas exchange
Partial pressure
-has moves from side with high pp to side with lower pp (high to low)
How is O2 transported in the blood
Red blood cells with protein haemoglobin (98.5%)
Dissolved in blood plasma (1.5%)
How is CO2 transported in blood
As HCO3 (bicarbonate) dissolved in blood plasma (70%)
As CO2 dissolved in plasma (7%)
Bound to haemoglobin (23%)
Explain how the partial pressure of air changes when moving in the body
When O2 is breathed in it has a pp of 160, once in lungs this drops, as it moves through body the pp continues to drop including as it crosses interstitial fluid and then once in the tissue
O2 moves from high pp in blood vessels to low pp in tissue
Same with CO2 but it is reversed – greater pp of CO2 in tissue as it is being produced there
The forces of these gases (pressure) drives the movement of them from areas of high pp to low pp
What is pulmonary ventilation
Process of moving air into and out of the lungs
Involved lungs, diaphragm, rib cage, sternum, intercostal muscles
Explain inspiration
Lungs- volume increase as they fill with air
Diaphragm- moves inferiorly and flattens
Rib cage and sternum- elevate
Intercostal muscles- contract and shorten
Explain expiration
Lungs- volume decreases as air leaves
Diaphragm- moves superior as it relaxes into its dome shape
Rib cage and sternum- depresses
Intercostal muscles- relax
What is boyles law
Volume is inversely proportional to pressure (e.g. Volume small then pressure between molecules is higher)
How does boyles law relate to breathing
Inspiration: volume alveoli increases, pressure between gases decreases
Expiration: volume alveoli decrease, pressure between gases increases
What is barometric pressure and intra-alveolar pressure
Barometric pressure (Pb) atmospheric pressure outside the body
Intra-alveolar pressure (Palv) pressure inside alveoli
Explain relationship between Palv and Pb when breathing
End of expiration:
Pb= Palv
No air flow
During inspiration:
Movement of body parts followed by movement of air
Inspiration = increased volume lungs –> reduced pressure below Pb
Following reduce in pressure, air naturally flows from area of high pressure to low pressure and can therefore move in to lungs
During expiration:
Volume of lungs decreases –> pressure increases
Air moves from high pressure to low pressure and therefore out of lungs and body
What causes intra-pleural pressure
Pressure in pleural cavity
What forces promote alveoli recoil
The fine, elastic fibres covering the alveoli and the surfactant fluid that coats alveoli to reduce surface tension (else alveoli would collapse)
What forces promote lung expansion
When intra-pleural pressure is less than intra-alveolar pressure
- visceral pleura adhering to parietal pleura via pleural fluid contributes to intra-pleural pressure
- without this adhesive force intra-pleural pressure would increase above intra-alveolar pressure and lungs would collapse
What diffusion type causes the movement of gases
CO2 and O2 pass through capillaries and tissues via simple diffusion - area high conc. to area low conc.
What is pulmonary volume
Volume of air involved in different stages of breathing
Involves tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume
What is tidal volume
Amount of air inspired or expired with each breath (done at rest) e.g. Breath in 500mL, breath out 500mL
What is inspiratory reserve volume
Amount of air that can be forcefully inspired after inspiration of tidal volume
What is expiratory reserve volume
Amount of air that can be forcefully expired after expiration of tidal volume
What is residual volume
Volume of air that still remains in respiratory passages and lungs after most forceful expiration
What is pulmonary capacity
The sum of two or more pulmonary volumes
Involves inspiratory capacity, functional residual capacity, vital capacity, total lung capacity
What is inspiratory capacity
Tidal volume + inspiratory reserve volume
Maximum amount of air someone can inspire after expiration
What is functional residual capacity
Expiratory reserve volume + residual volume
Amount of air remaining in the lungs at the end of a normal expiration
What is vital capacity
Inspiratory reserve volume + tidal volume + expiratory reserve volume
Maximum volume of air that can be expelled from the respiratory tract after maximum inspiration
Healthy person would have great vital capacity than someone unhealthy
What is total lung capacity
Inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volumes
Define respiratory rate
Number of breaths taken per minute
Define minute ventilation
Total amount of air moved in and out of respiratory system each minute
Tidal volume x respiratory rate
Define anatomic dead space
Space where gas exchange is taking place (whole respiratory system)
Define alveolar ventilation
Volume of air available for gas exchange per minute
Different ways to measure lung function
Static- doesn’t involve time, uses spirometer, to measure capacities and volumes
Dynamic- involves time, uses vitalograph
Both can be used to diagnose and monitor diseases
Explain dynamic lung function
Measures:
Forced vital capacity: maximum volume of air forcefully expired as fast as possible after a deep breath in
Forced expiratory volume in 1 sec: volume of air expired in first second of test
Forced expiratory volume 1%: FEV1sec expressed as % of FVC (FEV1sec divide FVC x 100) means that in first second you breath you release % of air in your lungs
x axis = time, y axis= lung volume in life’s
FVC read straight from graph where the line plateaus
What is obstructive lung disease
Can get all air out but takes longer
Line not as steep on graph
Person has narrower airways
FVC- normal, other two will be less than normal
Indicates diseases such as asthma, emphysema, bronchitis
What is restrictive lung disease
Trouble expanding lungs, can’t get all air out even though rate may be the same
FVC - considerably low, FEV1sec- a bit lower, FEV1% - normal
Diseases such as pulmonary fibrosis, obesity, scoliosis
What are the functions of the nasal cavity
•Passageway for air
•Cleans air (hair, mucus, cilia)
•Humidifies and warms air
-warms to body temp achieved by warm blood flowing through capillaries throughout cavity
-humidifies via moisture coming from mucus and excess tears that drain in to nasal cavity
•olfaction via olfactory receptors located at most superior aspect of nasal cavity
•sound of voice - echoes through nasal cavity
