Respiratory Anatomy Flashcards
What is the name for the process for breathing?
Cyclical respiratory muscle contraction
What are turbinates?
Found behind the nose
Membrane structure which provides large surface area for heating and humidifying the air
Disrupts air flow, creating resistance to increase the chance of inhaled particles being trapped
Why does air need to be humidified before entering the lungs?
To prevent the alveolar linings from drying out
O2 and CO2 can’t diffuse through dry membranes
What are the lobe layout in the lungs and why is this?
3 lobes on right
2 lobes on left
Asymmetrical as need space for heart on left
What is the respiratory quotient and how do you calculate it?
Ratio of CO2 produced to O2 consumed
CO2/O2
Name and describe the two autonomic receptors for respiratory:
Muscarinic- Ach- constriction M3 muscarinic receptor, innervate mucous glands (parasympathetic)
Adrenergic- epinephrine- dilation- B2 receptor (sympathetic)
What are NANC nerves and how can they work in changing diameter of blood vessels?
Non Adrenergic Non Cholinegeric nerves
Inhibitory- efferent fibres causing bronchodilation
Excitatory- sensory fibres leading to bronchoconstriction, relax airway smooth muscle by releasing nitric oxide and vasoactive intestinal peptide.
What is asthma?
Recurrent attacks of breathlessness
The airway obstruction is mostly reversible with treatment
What is COPD?
Airflow obstruction which is usually progressive, not fully reversible
From the result of chronic inflammation
What are the causes of asthma?
Genetic: age, atopy, gender
Environmental: Allergens, pollutants, smoke
What is extrinsic and intrinsic asthma?
Extrinsic- atopic, episodic, younger early onset, raised IgE levels (allergic)
Intrinsic- non- atopic, chronic, late adult onset, exercise, normal IgE levels (non-allergic)
What are the causes of COPD?
More than 90% due to smoking but only 10% of smokers have it
2% genetic, anti-alpha trypsin deficiency
What are exacerbations?
A sustained worsening of the patients symptoms from their usual
What is diurnal variation?
From day to day, symptoms are different
What is the larynx compromised of?
Thyroid cartilage
Which cells produce mucus?
Goblet and submucosal cells
What is the trachea compromised of?
Incomplete rings made of hyaline cartilage
What are the three neural control components in respiration?
- Generation of alternating inspiration/ expiration rhythm
- Regulation of magnitude of ventilation
- Modified respiratory movements
e.g voluntary= speech, involuntary= cough/sneeze
Describe the respiratory tree from top to bottom:
Nasal passages
Mouth
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Name the 3 key anatomies in the body for breathing:
Diaphragm
External intercostal muscles
Thorax
Describe inspiration:
The diaphragm contracts and pulls out The intercoastal muscles contract
Pulls rib cage up and out
thoracic cavity expands, active process
Describe expiration:
When nerves stop firing, the diaphragm relaxes, the external intercostal muscles relax and thoracic cavity reduces passive process
Where in the brain is breathing controlled?
Medulla oblongata
In which complex is the respiratory rhythm generated?
Pre- Botzinger complex
Which nerves initiate inspiration?
Bursts of action potentials in spinal motor nerves
The phrenic nerve innervates diaphragm The intercostal nerves innervate external intercostal muscles
Describe the process how lungs don’t over inflate:
Lungs have pulmonary stretch receptors the Hering-Breur reflex is activated
When the lungs inflate, the negative feedback causes the inspiratory centre to stop firing to phrenic nerve so diaphragm doesn’t contract and activate the stretch receptor in the lung
What is the equation to work out flow of air?
Flow= (P alvelor- P atmostphere)/ Resistance
What is hyperventilation?
An increase in ventilation so a decrease in CO2
What is Boyles law and how does this relate to breathing?
P1V1=P2V2
Compression of lungs so if volume decreases, pressure increases so air moves out
How does Fick’s law relate to efficient alveolar structure for efficient gas exchange?
The shorter the distance and the greater the surface area through which diffusion takes place, the greater the rate of diffusion
Describe the structure and components of the alveoli:
Single layer of flattened type 1 alveolar cells
5% made of type 2 alveolar cells, which produce pulmonary surfactant
Pores of Khon in the walls between adjacent alveoli to permit airflow between these
What is transpulmonary pressure (Ptp)?
It is a difference in pressure between the inside and outside of the lungs
What is intrapleural pressure? (Ppip)
As the thorax expands volume increases
The intrapleural pressure decreases and lungs expand
The pressure across the wall of lung increases
How do you calculate transpulmonary pressure?
Alveolar pressure- Intrapleural pressure
What is lung compliance?
The magnitude of change in volume
What does lung compliance depend on?
The surface tension of water in alveoli- type 2 alveolar cells secrete pulmonary surfactant in alveoli which helps prevent collapse
The stretchability- how easily they open and close from the connective tissue (elastin)
What occurs in the pulmonary capillaries?
O2 from the atmosphere enter the alveoli which binds to haemoglobin and carried to the tissues
CO2 which was dissolved into the blood by bicarbonate ions made back into CO2 to be released
Why does oxygen need haemoglobin?
Oxygen has a low solubility in blood
How does haemoglobin work?
Each haemoglobin can hold four oxygen molecules
Works by association, once one oxygen is bound the other O2 can combine more freely and vice versa
What occurs in the systemic capillaries?
HbO2 dissociate back into haemoglobin and O2 and leaves red blood cells
Hb combines of H+ ions to form HHb
Most CO2 is converted into HCO3- which is in the plasma
Which two chemoreceptors control the magnitude and rate of ventilation?
Peripheral and central
How do peripheral chemoreceptors work?
Found in carotid and aortic bodies
Rich in O2- respond to changes in blood pH (H+) and gas content
How do central chemoreceptors work?
Very sensitive, stimulated by an increase in H+ ions in brains extracellular fluid
An increase can both cause increasing contraction and ventilation
What is cyanosis?
Blueness of skin resulting from insufficiently oxygenated blood in arteries
What is hypercapnia?
Excess CO2 in arterial blood
What is hypocapnia?
Lower than normal CO2 in arterial blood
What is hypoxia?
Insufficient O2 at cellular level
What is apnea?
Where your breathing stops due to the airways becoming too relaxed and narrow when sleeping
