Respiration Flashcards
What are 4 functions of the respiratory system?
- Exchange of gases between atmosphere and blood
- Regulation of blood pH by loss of C02
- Protection from external pathogens and irritants
- Vocalisation
What kind of epithelium are the alveoli made of ?
Flattened squamous epithelium
What do the alveoli produce to keep surface tension?
A substance called surfactant produced by Alveoli type2
What protein is fundamental for lung function?
Elastin
What is elastin made of?
It is arranged as a set of protein fibres cross linked through lysines
What enzyme degrades elastin?
Elastase
What protein inhibits elastase?
alpha-1-antitrypsin
What is pleurisy?
Inflammation of pleura
What muscles are involved in passive or quite breathing?
Diaphragm. It is pulled down when we breathe in and pulled upwards when we exhale
What muscles are involved in active or forced breathing?
INSPIRATION = Diaphragm, external intercostal muscles, scalene and sternocleidomastoids
EXPIRATION= Internal intercostal and abdominal muscles
What are the 4 main patterns that a spirometry can show?
- Normal pattern
- obstructive pattern
- Restrictive pattern
- Combined
What pattern do asthma and COPD show?
Obstructive patterns
How do FVC and FE1V change with obstructive pattern?
Disproportionately
How do FVC and FE1V change with restrictive pattern?
Proportionately
What is COPD
Chronic Obstructive Pulmonary disease
What is partial pressure of Oxygen in lungs and arterial blood?
100 mmHg
What is partial pressure of CO2 in lungs and arterial blood?
40 mmHg
What is partial pressure of Oxygen in tissues and venous blood?
40 mmHg
What is partial pressure of Co2 in tissues and venous blood?
45 mmHg
What is oxidation state of oxygen in haemoglobin?
Fe2+
How many heme groups does Hb have?
4
How many molecules of O2 can Hb bind to?
4
How many atoms of oxygen bind to Hb?
8
What happens to Hb when pH changes?
More acidic: when hydrogen atoms are around Hb gives up oxygen more easily.
What happens to Hb when temperature changes?
The colder it gets , the harder it is for Hb to give up oxygen
What happens to Hb when partial pressure of CO2 changes?
When p.p. of CO2 increases, oxygen is lost more easily
Why is Carbon monoxide toxic?
It binds to Hb more strongly than oxygen creating a carboxyhaemoglobin leading to anoxaemia
Smoking , Co and pressure
Smoke from cigarettes contains CO and binds to 10% of Haemoglobin making it useless. Blood leads to circulate faster so you increase blood pressure.
Other types of Hb and their binding
Myoglobin > Foetal Hb > Hb
Percentage of Co2 transported in blood
7% diluted in blood
70% travelling as bicarbonate ion HCO3-
23% can bind directly to haemoglobin but not heme group
What enzyme catalyses the reaction of CO2 with H20 to make carbonic acid?
Carbonic anhydrase
What will the carbonic acid be broken down into?
Bicarbonate ion and a proton
What is the proton from carbonic acid reaction used for ?
It will bind to the Hb to dislodge oxygen
What is the chloride shift?
It is the exchange of a bicarbonate ion (HCO3-) for a chloride ion (cl-) present in plasma. It is operated by an anti porter on the surface of erythrocytes
What is the increase in CO2 called ?
Hypercapnia
What is the decrease in O2 called?
Hypoxia
What is Emphysema?
Destruction of alveolo which reduces surface area for gas exchange
What is Fibrotic lung disease?
thickened alveolar membrane slows gas exchange
What is Pulmonary edema?
Fluid in interstitial space which increases diffusion distance
What is Asthma?
Increased airway resistance decreases airway ventilation
Name different types of hypoxia
- Hypoxic Hypoxia : due to high altitude
- Anaemic Hypoxia: oxygen not binding to enough Hb
- Ischemic hypoxia : reduced blood flow
- Histotoxic hypoxia : cells cannot take in oxygen because they are poisoned
Effects of smoking on respiratory tract and respiration
- Irritates bronchioles increasing mucus while decreasing cleaning function(cilia) leading to obstruction of airways and gas exchange difficulties and therefore hypertension
- Carbon monoxide leads to hypoxia and hypertension
- Emphysema and Chronic bronchitis (COPD)
- Inhibits synthesis of elastin
- Causes cancer because of carcinogenic components
