Compendium 4 Flashcards by Richard Nguyen

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

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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)

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List structures of the respiratory system

Conducting zone:
Nasal cavity
Pharynx
Larynx
Trachea 
Tracheobronchial tree

Respiratory zone: 
Alveoli
Respiratory membrane 
Lungs 
Pleura

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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)

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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

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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

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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

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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)

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Pharynx: explain laryngopharynx

Lies posterior to epiglottis, superior to larynx

Stratified squamous epithelium

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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)

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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)

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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

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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

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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

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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

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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

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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)

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List the pathway of air

In nose
Nasal cavity
Pharynx
Larynx
Trachea
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioles 
Tertiary bronchioles
Respiratory bronchioles 
Alveoli

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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)

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How is O2 transported in the blood

Red blood cells with protein haemoglobin (98.5%)

Dissolved in blood plasma (1.5%)

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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