Lungs Flashcards
What is the carrying capacity of Haemoglobin
200mls of oxygen per litre of blood
1g of Hb can transport 1.39ml oxygen when fully saturated
Why is it important to have haemoglobin concentrated in the RBC
To reduce viscocity of the blood
Why is Haemoglobin affinity significant
Higher affinity at higher pO2s encourages O2 uptake at the lungs
and lower pO2s at the low concentrations encourages dissociation,
this is because of the hydrogen ions
What is the symbol for oxyhaemoglobin
This has to be a fully oxygenated haemoglobin,
so it’s Hb4O8
nothing else counts as oxyhaemoglobin
DPG
is a metabolic product, that increases CO, which increases the leftshift of the graph
Myoglobin
stores oxygen at the skeletal muscles
Where does carbon dioxide bind to a protein
at the amine groups
How many times more soluble is CO2 than oxygen
well, 20 times
and 25 times are both acceptable
Roughly including the byproducts of CO2, how much CO2 is transported in RBC, and how much CO2 is transported in plasma
30% in RBC
70% in plasma
What is the difference between rapidly formed bicarbonate and slowly formed bicarbonate
rapidly formed is with an enzyme (20%) in RBC
it diffuses out, forming a 60% of CO2 in the plasma
n.b, write an equation on how a carbamino protein is formed and note the significance
CO2+R-NH2=
RNHCOO-+H+
N.B, this forms a hydrogen ion that can change the oxygen affinity,
and increase the uptake of CO2 through HHb
Haemoglobin facts on why Haemoglobin is the main protein that binds to CO2
There is 4 times more haemoglobin than other plasma protein
Hb has a greater affinity for CO2 than other plasma proteins
What is another function of Haemoglobin
it acts as a buffer, in it’s formation of HHb
CO2 dissociation curve
depends on PCO2
There is no saturation as CO2 is very soluble in plasma
Hypercapnia
Hypocapnia
Apnoea
dyspnoea
Hypercapnia is high CO2
Hypocapnia is low CO2 levels
Apnoea is no breathing
Dyspnoea is sensation of breathlessness
What happens when you hyperventilate too much
You will become Hypocapnic
Then you might faint
because CO2 levels often regulate the level of blood flow to the brain
Cerebral arteries constrict
Peripheral chemoreceptors
Carotid goes into sinus nerve
which goes into the glossopharyngeal nerve to the medulla oblongata
How are peripheral chemoreceptors stimulated
Carotid ones can do pO2, pH and pCO2
And essentially, hypoxia hypercapnia hemorrange acidosis increased sympathetic activty
and sodium cyanide are all possibile stimuli
The peripheral chemoreceptors
are reflex chemoreceptors, and the experimental method is getting people to breathe nitrogen bags
Central chemoreceptors
These are 3 chemoreceptors found at the VENTRAL surface of the medulla oblongata
Why do central chemoreceptors take so bloody long to respond
Because it detects H+ in the brain extracellular fluid
The limited Carbonic anydrase in the brain cerebrospinal fluid really limites the speed
Ondine’s curse
no central chemoreceptors, you tend to hold your breath for longer because of the insensitivity to O2.
this may get your PaO2 to extremely low levels, that causes apnoea, due to you stopping ventilation
What is the number of Alveoli
300million
What is the systolic pulmonary/diastolic pulmonary ratio
22/10
What is the systemic systolic/diastolic ratio and mean
120/80 mean 93
calculated as
DP+1/3(SP-DP_
wHEN does the blood stop being pulsatile in pulmonary
capillaries
What are the pillars in the car park
interstitium
Why is it low pressure system
Mainly to decrease oedema, but also has functions of increasing the time for diffusion
What is a reason why exercise increases oxygen uptake
Blood pressure increases, so more oxygen can flow up to the apex of the lungs
What is the PaO2 at the apex and base
140mmHg at the apex
30 at the base
Haldane effect reason
HHb is more basic, so it binds with CO2 much better, this is why it helps with the loading of CO2
IT IS DEFINED AS THE DEOXYGENATION OF BLOOD INCREASES, IT’S ABILITY TO CARRY co2 INCREASES. tHIS IS BECAUSE LOW OXYGEN content triggers the floowing equilibrium to shift to the right
H+HbO2=HHb+O2
and likewise increased CO2 means increased H2CO3=more H+
Medullary respiratory centre
generation of the respiratory rhythm
1) inspiration
2) expiration
Pons-switch off inspiration, thus regulating inspiration volume and acts as a secondary respiratory centre
1) rhythm
2) pons and medulla
3) receive input from chemoreceptors, lungs and other
4) Output to the phrenic nerves
Cortex, limbic system, hypothalamus can also help with controlling breathing
Aortic chemoreceptors
blood oxygen and CO2 but not pH
What is the peripheral chemoreceptors completely responsible for
Peripheral chemoreceptors are completely responsible for all the increase in ventilation that occurs in response to arterial hypoxemia
Hering breuer reflex
Lung stretch receptors stimulated
Vagal afferent activated
goes to medulla oblongata
sympathetic efferent goes into the bronchioles bronchodilate the sodium beta adrenoceptor
Emphysema
A person with emphysema typically has a positive intrapleural pressure during exhalation
The airsacs rupture
elasticity of stuff fucked
the vacuum is decreased probably due to decreased elasticity
Chronic bronchitis
Chronic inflammation of bronchial tree
causes overproduction of mucus and mucus sometimes accumulate
This can lead to pulmonary constriction, hence pulmonary hypertension
and insufficient blood supply
Hypoxia and Hypotension
1) disease condition leads to right heart failure=>this leads to insufficient pressure gradient
2) This leads to pulmonary constriction leading to pulmonary hypertension
3) Insufficient blood supply leads to systenic hypoxia
1) Disease condition leads to low PO2 in alveoli
2) Constriction of blood vessel supplying alveoli with low PO2 leads to pulmonary hypertension
3) Pulmonary hypertension eventually leads to right heart failure
Pneumonia
inflammation of lung airways, and restricts air from reaching alveoli
diffusion gradient limited by the distance
Salbutamol
a beta adrenoreceptor agonist
Why is it more dangerous to have an infection at the respiratory area
Because it is closer to the blood vessels
What kind of epithelium lines the nasal cavity?
The pseudostratified ciliated epithelium
Why does smoking lead to accumulation of mucus
Cilia are inhibited by tar
Mucoserous glands
They are found in the submucosal layer and secretes both serous fluid and mucus, and are found only in the nasal cavity
What causes resonance to vocalisations
The hollow sinus
Nasopharynx
superior region of pharynx interfacing with the nasal cavity. The inferior boundary is demarcated by the soft palate
Oropharynx
middle region of the pharynx that conducts both air and food
Laryngopharynx
Inferior region of the pharynx between the larynx and epiglottis.
Also conducts both air and food.
Both oropharynx and larynpharynx are lined with squamous non-keratinised epithelium to resist the abrasion caused by food
Describe the process of ingestion
epiglottis is an elastic cartilage structure, which during swallowing closes to shunt the bolus into the oesophagus. The soft palate also closes off the entry to the nasopharynx
Entry of food can disrupt the delicate psudostratified epithelium
Which generation does the respiratory zone begin?
20-23
which generation does the bronchioles of the conducting zone occupy excluding terminal
10-15
Which generation do terminal bronchioles occupy
16-19
What is the muscle in the trachea
The trachealis, it allows for the narrowing of the trachea, and distendable, so it accommodates the oesophagus when it expands during swallowing
Club cells
watery substance that hydrates the epithelium and contains antimicrobial enzymes
role of smooth muscle in bronchioles
It is critical for controlling lumen diameter, as a means to regulate the intake of air by controlling the tone of the airway
What are type 1 cells called
squamous pneumocytes, very thin cells, and
it is 0.5 uM THICK
How is the capillary endothelium and the common elastic basement membrane made?
It is produced by fibroblasts
Number of segments of each lung
8 on the left
10 on the right
Why is neural rhythm important
ensures that inspiratory and expiratory effectors are not activated simultaneously so increase/decrease in lung pressure is achieved
Where are the stretch activated
mechanoreceptirs
They are activated by stretching caused by radial traction during inspiration
How is low pressure achieved during the branching of the pulmonary arterioles
it increases CSA and lowers resistance. This reduces the pulsatility of the pressure to give uniform, low pressure blood flow
