Respiration Flashcards
What are the 2 types of respiration ?
Internal - Within the cell,
CO2 produced – Glycolysis Krebs Cycle
O2 consumed – Oxidative Phosphorylation.
External - Ventilation
Exchange and transport of gases around the body
What are the 2 types of respiration ?
Internal - Within the cell,
CO2 produced – Glycolysis Krebs Cycle
O2 consumed – Oxidative Phosphorylation.
External - Ventilation
Exchange and transport of gases around the body
What is the Conducting Zone ?
conducting zones provide pathways to get air to and from respiratory zone where gas exchange takes place
Conducting zone – transports gases into the respiratory zone, upper airways, trachea, mouth and throat.
It warms incoming air to body temp
Nose Nasopharynx (Mouth) Oropharynx Pharynx Larynx Trachea Bronchial Tree to respiratory bronchioles
Why do you not want cold air entering a warm blood supply ?
When u get to the exchange, don’t want cold gases entering a warm blood supply. Important to stop the lower airways drying out and becoming desiccated. By humidifying it u prevent desecration of the lower airways.
What is the structure of Bronchiol Wall ?
Reinforced with cartilage rings - helps prevent airways from collapsing
Smooth Muscle
Mucous glands - traps particles
Elastic
What is the structure of Bronchiol Wall ?
Reinforced with cartilage rings - helps prevent airways from collapsing
Smooth Muscle
Mucous glands - traps particles
Elastic
What does the Respiratory Epithelium consist of ?
Ciliated Epithelia
Goblet cells
Sensory Nerve Endings - helps direct smoke and CO in the airways
What happens if Bronchioles lack cartilage support ?
Lack cartilage support – more subject to collapsing, elastic surrounding tissue nature which keeps bronchioles open
What happens if Bronchioles lack cartilage support ?
Lack cartilage support – more subject to collapsing, elastic surrounding tissue nature which keeps bronchioles open
What are the main features of alveoli ?
Large surface area
Fed from terminal bronchiole
Thin walled provides huge area and small distance for diffusion
3 million alveoli in lungs
How is the air blood barrier formed ?
A ‘sandwich’ created by flattened cytoplasm of type I pnemuocyte and the capillary wall
How is the air blood barrier formed ?
A ‘sandwich’ created by flattened cytoplasm of type I pnemuocyte and the capillary wall
What happens during inspiration ?
During inspiration: Atmospheric pressure is greater than lung pressure so air moves into the lungs
Pressure in alveoli is less than atmospheric pressure so air moves down into the lungs.
What happens during expiration ?
During expiration: lung pressure is greater than atmospheric pressure so air moves out of the lungs
Pressure in alveoli is greater than atmospheric pressure so air moves down alveoli out of lungs.
How does air movement follow principles of Boyle’s Law ?
The increase in volume, leads to a reduction in pressure. Air moves into the lungs down the pressure gradient
What happens to the lungs and diaphragm during inspiration ?
Rib muscles contract during inspiration and moves down, lungs expand, pressure inside lungs is lower than atmospheric so air moves into lungs.
External Intercostal muscle is in between the ribs, when they contract it helps move the ribcage up and expand the thoracic body.
Increase in lung and thoracic volume and air moves in
What are Scalenes and what do they do ?
Scalene muscles in the neck that attach to top of ribcage. Contracting of these helps move the ribcage up and forward, helping with expansion of thoracic capacity.
What are Scalenes and what do they do ?
Scalene muscles in the neck that attach to top of ribcage. Contracting of these helps move the ribcage up and forward, helping with expansion of thoracic capacity.
How does Quiet Expiration work ?
Quiet expiration is a passive process using elastic recoil
There are no primary muscles of expiration.
Relaxation of external intercostal muscles
Recoil of the lungs (elastic forces returning lungs to original size)
Diaphragm relaxes
What is the Pleura and how does ?
Pleura cavity filled with secretions.
It prevents lungs from sticking to the chest wall.
Does this by allows the lung and chest wall to move over each other an expand together, prevents them sticking together
How do forces in lungs and chest balance ?
At rest these inward and outward forces balance – as a result the pressure in the intrapleural space is less than atmospheric pressure.
Forces in the chest wall are normally working in an outwards direction.
Elastic nature of lungs pull inwards, chest pushes outwards and interpleural space between them.
Very slight vacuum exits in that interpleural space, but its crucial for maintaining lung volume (negative pressure)
How do forces in lungs and chest balance ?
At rest these inward and outward forces balance – as a result the pressure in the intrapleural space is less than atmospheric pressure.
Forces in the chest wall are normally working in an outwards direction.
Elastic nature of lungs pull inwards, chest pushes outwards and interpleural space between them.
Very slight vacuum exits in that interpleural space, but its crucial for maintaining lung volume (negative pressure)
How can a Pneumothorax (collapsed lung) arise ?
Some kind of trama has created a breach in the chest wall, broken the pleural membrane on the chest side. Equilibrium at atmospheric pressure means you will lose the pressure and air inside the lungs and lungs will collapse. Could put a test tube in and evacuate air from the interpleural space, drive air out of this space, reestablish the partial vacuum.
What is Compliance ?
Measure of elasticity
The ease with which lungs and thorax expand during pressure changes
What is the difference between low and high compliance ?
low compliance - more work required to inspire
eg. pulmonary fibrosis – lung paranchyma is more rigid
high compliance - often also involves more difficulty expiring (loss of elastic recoil), breakdown of tissue
eg. emphysema
What are the 2 major components to the elastic recoil of the lungs ?
‘Anatomical’ component – elastic nature of cells and extracellular matrix.
Elastic recoil due to surface tension generated at air-fluid interface
What is Surfacant and what is it produced by ?
Surfactant produced by Type II pneumocytes. It is composed of a number of lipids and proteins
What problem is overcome with surfactant ?
The problem of smaller alveoli collapsing is overcome by the production of surfactant.
What does the presence of surfactant do for alveoli ?
Small alveoli will have a higher density of a surfactant compared to a larger alveoli, this balances out the surface tension between all alveoi and stops small alveoli collapsing.
How can we measure lung volume ?
Spirometer
What is Anatomical dead space ?
Anatomical dead space - volume of conducting airways
At rest approximately 30% of inspired air volume(150ml) trachea, bronchi, bronchioles, are not involved in gas exchange 100-150ml in the average person. Tidal volume – amount you breath in an out in a breath at rest (500ml)
What is Physiological dead space ?
Physiological dead space – volume of lungs not participating in gas exchange
conducting zone + non-functional areas of respiratory zone
Normally the two values are almost identical
An area where gas can get to but hard to exchange gas
What is Physiological dead space ?
Physiological dead space – volume of lungs not participating in gas exchange
conducting zone + non-functional areas of respiratory zone
Normally the two values are almost identical
An area where gas can get to but hard to exchange gas
List the lung volumes
FEV is lower for someone with asthma.
ERV – expiratory reserve volume, at end of a normal expiration, how much air is eft in you lungs down to the residual volume.
Tidal volume – how much you breathe at rest 500ml
IRV – Inspiratory reserve volume, the volume after you’ve breathed in, from the end of tidal volume up to vital capacity
IRV + ERV TD = Vital Capacity. These are dynamic values
FRC = ERV + RV. The total amount of air left in lungs after end of a normal expiration.
IC – End of a normal expiration, up to total capacity.
RV + VC = Total Lung Capacity
Vital capacity – how much you can breathe in by force
Residual Volume – air left in lungs
What happens to IVR and EVR during exercise ?
Rate and depth of breathing when exercising increases, tidal volume increases so the reserve volumes must go down, IRV and ERV.
What is Poiseuille’s Law ?
Airway resistance is proportional to gas viscosity and the length of the tube but is inversely proportional to the fourth power of the radius.
What is Poiseuille’s Law ?
Airway resistance is proportional to gas viscosity and the length of the tube but is inversely proportional to the fourth power of the radius.
What factors impact on airway resistance ?
Airway Diameter:
Increased mucus secretion will effectively reduce airway diameter – increased resistance.
Oedema – increased fluid retention in the lung tissue will cause swelling and narrowing of the airways – increased resistance.
Airway collapse – for example during forced expiration, narrows airway, increased resistance.
What factors impact on airway resistance ?
Airway Diameter:
Increased mucus secretion will effectively reduce airway diameter – increased resistance.
Oedema – increased fluid retention in the lung tissue will cause swelling and narrowing of the airways – increased resistance.
Airway collapse – for example during forced expiration, narrows airway, increased resistance.
How is Bronchial diameter regulated via the ANS ?
Autonomic Nervous System:
Parasympathetic: acetylcholine is released from the vagus, acts on muscarinic receptors leads to CONSTRICTION
Sympathetic: release of norepinephrine from nerves – weak agonist leads to DILATION
What humeral factors regulate bronchial diameter ?
Humoral factors:
Epinephrine circulating in the blood – better agonist leads to DILATION
Histamine – released during inflammatory processes – leads to CONSTRICTION.
What is Daltons Law ?
Dalton’s Law – The total pressure of a mixture of gases is the sum of their individual partial pressures.
What is the structure of Haemoglobin ?
4 haem groups
Tetrameric structure with 4 subunits
68kD molecular weight
2 alpha and 2 beta chains
Haem unit is a porphyrin ring with a single iron atom
O2 will bind to the Fe2+
What are the 2 states haemoglobin exists at ?
In tense state low affinity for O2
In relaxed state high affinity for O2
What happens to the Oxygen-Haemoglobin dissociation curve
when temp is increased or decreased ?
High temp - higher O2 affinity
Low temp - lower O2 affinity
What is the Bohr Effect ?
A shift caused by pH change.
More alkaline - higher O2 affinity
More acidic - Lower O2 affinity
What is the effect of 2,3 Diphosphoglycerate on the Oxygen-Haemoglobin dissociation curve ?
Low amount means higher O2 affinity
High amount means lower O2 affinity
What happens in tissues undergoing active respiration and how does this effect the dissociation curve ?
Increased temp
Increased CO2 production
Decreased pH
Shifts curve the the right, decreased O2 affinity so more O2 is released to tissue
What is the difference between Adult Hb and Fetal Hb ?
In Fetal-Hb the β-globin chains are replaced by γ-chains. There is a leftwards shift in Hb-O2 curve – higher affinity for O2.
How is CO2 transported by blood ?
The Blood carries CO2 as
Dissolved carbon dioxide
Carbonic acid
Bicarbonate
Carbonate
Carbamino compounds
What are the 2 categories of Lund disease ?
Obstructive - reduction in flow through airways
Restrictive - reduction in lung expansion
Both reduce ventilation
What is a flow loop/volume ?
Flow loops/volume – rapid increase in flow up to peak expiratory flow, then a gradual drop-off in the flow rate. Dynamic compression effect on airways that prevents
What could the narrowing of airways in obstructive lung disease be due to ?
Narrowing could be due to:
Excess secretions
Bronchoconstriction - Asthma
Inflammation
In all cases there is an increased resistance to the flow of air.
What happens to FEV during Obstructive lung disease ?
Obstructive lung disease, the patient’s FEV1 is reduced to less than 80% of the FVC
What does an Obstructive Volume-Time curve look like ?
In many cases FVC is unaltered but there is the decrease in FEV1
Time is longer in obstructive
What do Obstructive Flow-Volume Loops look like ?
The initial flow and peak flow can be similar to normal but there is a sharp fall in flow-rate giving a concave shape to the curve.
Vital Capacity stays similar
What are some common examples of Obstructive diseases ?
Chronic Bronchitis Persistent productive cough and excessive mucus secretion (three consecutive months in last two years)
Asthma - inflammatory disease
Chronic obstructive pulmonary disease (COPD) - structural changes in the lung
Emphysema –loss of elastin, sub-type of COPD
What are the 2 ways you can trigger Asthma (hyper-active airways) ?
Trigger can be either,
Atopic (extrinsic) – allergies, contact with inhaled allergens.
Non-Atopic (intrinsic) – Respiratory infections, cold air, stress, exercise, inhaled irritants, drugs.
If Asthma is triggered, what is the response ?
Response: Movement of inflammatory cells into the airways, release of inflammatory mediators such as histamine and subsequent bronchoconstriction.
What is the short acting solution to Asthma ?
Short-acting β2-adrenoreceptor agonists – salbutamol.
Causes dilation of airways.
What is the longer acting solution to Asthma ?
Longer acting treatments
Inhaled steroids. Glucocorticoids such as beclometasone, act to reduce the inflammatory responses.
Long acting β-adrenoreceptor agonists
How does reduced chest expansion cause restrictive lung disease ?
Chest wall abnormalities
Muscle contraction deficiencies
How does loss of compliance (fibrosis) cause restrictive lung disease ?
Normal aging process
Increase in collagen
Exposure to environmental factors
What happens to Vital Capacity during restrictive lung disease ?
VC is reduced
What happens in Restrictive Volume-Time curves ?
Reduction in FVC, but FEV1% can remain unaltered or even increase.
What happens in Restrictive Flow-Volume loops ?
The shape of the relationship tends to be normal but there is a reduction in the volumes of air moved. Also there can be a reduction in the peak flow.
What is Asbestosis ?
Slow build up of fibrous tissue leading to loss of compliance.
What is the Dorsal Respiratory Group ?
Controls Inspiration by sending signals to the inspiratory muscles
What is Ventral Respiratory Group ?
Ventral Respiratory Group (VRG)
Controls Inspiration and expiration
Inactive during quiet respiration
During activation helps control forceful inspiration and expiration
How does the Pons regulate rate and depth of breathing ?
Two centres in the Pons sends stimuli to the medulla to regulating rate and depth of breathing
What do the pneumotaxic and apneustic centre do ?
pneumotaxic centre increases the rate by shortening inspirations.
inhibitory effect on inspiratory centre
apneustic centre - increases the depth and reduces the rate by prolonging inspirations.
stimulates inspiratory centre
What do the pneumotaxic and apneustic centre do ?
pneumotaxic centre increases the rate by shortening inspirations.
inhibitory effect on inspiratory centre
apneustic centre - increases the depth and reduces the rate by prolonging inspirations.
stimulates inspiratory centre
What is the Hering-Breuer reflex ?
Stretch receptors in the lung send signals back to the medulla to limit inspiration and prevent over-inflation of the lungs.
How do central chemoreceptors respond to an increase in CO2 ?
Central Chemoreceptors – Monitor conditions in the cerbro-spinal fluid. Sensing carbon dioxide and pH.
Indirect response to a rise in CO2 - stimulation leads to an increase in ventilation.
What happens when peripheral chemoreceptors in the carotid body and aortic arch are stimulated ?
Stimulation leads to an increase in ventilation.
In response to
Increase in CO2
Decrease in pH
Decrease in O2
