Topic 7 The Respiratory System Flashcards
How many breaths does the average person take when at rest?
12-18 per minute
What are the components of the respiratory system?
- The airway
- The lungs
- The muscles of respiration
What is the purpose of the cilia in the nasal cavities?
To warm the air and trap any potentially harmful particles
What are ‘cardiac impressions’?
The special grooves on each lung in which the heart sits
What do terminal bronchioles further divide into?
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
What shape is the base of each lung?
Concave
What is the term for the exchange between the body and the environment of CO2 and O2?
External respiration
What is the conduction zone?
The name given to the collective of the nasal passages, pharynx, larynx, bronchi and bronchioles
What are the components of the conduction zone?
- Nasal passages
- Pharynx
- Larynx
- Bronchi
- Bronchioles
Roughly how big, in an adult human, is the respiratory surface?
About 140m squared
What are the components of the respiratory zone?
- Bronchioles
- Alveolar ducts
- Alveoli
What is the respiratory zone?
Where gas exchange occurs during respiration
What is haemoglobin?
An iron-containing protein
How does haeomoglobin function?
It binds with oxygen in the lungs in order to transport it to tissues
What is ‘partial pressure’?
The amount of each individual gas in the atmosphere
What is haemoglobin?
An iron-containing protein present in red blood cells
What does haemoglobin do?
Binds to oxygen in the lungs and transports it to tissues
What is haemoglobin formed of?
Four polypeptide chains; two alpha & two beta chains
What is a haem group?
What gives haemoglobin its ability to bind to oxygen
What are haem groups comprised of?
An iron atom which is able to bind with an oxygen molecule
What is the force which governs binding of O2 to Hb?
Positive cooperativity
What is deoxyhaemoglobin?
Hb which does not have O2 bound to it
What biological factors affect Hb binding?
- CO2
- Acidity
- 2,3-DPG (2,3-diphosphoglyceric acid)
- Exercise
- Temperature
What is the Bohr effect?
The name for the influence which CO2 and acidity have on the affinity of haemoglobin for oxygen
A reaction between which molecules generates bicarbonate?
Water and carbon dioxide
What is the formula of bicarbonate?
HCO3
What is the equation for the reaction which produces bicarbonate?
H2O + CO2 H2CO3 H+ + HCO3
What does carbon dioxide combine with water to form?
Carbonic acid
Which enzyme is facilitates and speeds up the reaction that produces carbonic acid?
Carbonic anhydrase
What causes sickle cell disease?
A nucleotide substitution (a glutamic acid codon is converted to a valine codon)
What is the cause of the cell distortion in HbS (sickle cell disease)?
Valine amino acids binding to each other when the HbS becomes deoxygenated
Is sickle cell a recessive or dominant condition?
Recessive; two mutated alleles are required for the condition to develop
What is haemolysis?
The rupture and destruction of erythrocytes
What are thalassaemias?
A group of inherited autosomal recessive disorders
What do thalassaemias cause?
Anaemia
Alterations in what? is the principle driver of respiration in humans?
PCO2
Neurons from which regions of the brain synapse on to the diaphragm and intercostal muscles to regulate breathing rate?
Pontine and medullary
What are neuromuscular junctions?
They synapse chemical junction between a motor neuron and a muscle fibre
What are type 1 glomus cells?
Peripheral chemoreceptors which sense and respond to the oxygen, carbon dioxide and pH levels of the blood
What chemical do glomus cells release across the neuromuscular junction?
Dopamine
What is the effect of the dopamine that glomus cells release on nerves?
It causes afferent signals to be sent to the medullary respiratory centres, which in turn send action potentials to the phrenic and intercostal nerves
What is the overall effect or purpose of the dopamine released by glomus cells?
To increase the respiration rate
Which parts of the brain are involved with the control of breathing during speech and behavioural tasks which modify breathing?
- Motor cortex
- Thalamus
- Cerebellum
What is hypopnoea?
Reduction in airflow
In respiration, where does gas exchange occur?
In the respiration zone - the bronchioles, alveolar ducts and alveoli
How is most of the CO2 carried in the blood?
As bicarbonate
How is O2 carried in the blood?
Bound to haemoglobin which is present in erythrocytes
What is the Bohr effect?
The influence of CO2 and acidity on the affinity of haemoglobin for oxygen
What is the Haldane effect?
The influence of oxygen on haemoglobin transport of carbon dioxide
