the respiratory system Flashcards
what is internal/cell respiration?
the metabolic processes at which cells breakdown carbohydrates, amino acids and fats to produce energy or ATP
What are the products formed by oxidative phosphorylation?
CO2 and water
what does oxidative phosphorylation require to run?
an energy source and oxygen
what is the equation for respiration?
C6H12O6 + 2O2»_space;» 6H20 + 6CO2 +energy
What is external respiration?
the exchange of gases between body and environments - inhalation and exhalation cycle.
what does external respiration do?
it provides oxygen (inhalation), this is the input for energy production and metabolism.
it eliminates CO2 (exhalation) which is a waste product of metabolism. the blood transports C02 and O2 between lungs and tissues by diffusion
What does the respiratory system consist of?
lungs - in pleural sac in rib cage
Diaphragm - muscle responsible for inhalation and exhalation
where are the lungs contained?
the pleural sac in rib cage
What is the diaphragm?
a muscle responsible for inhalation and exhalation
what happens at inhalation?
the diaphragm muscle contracts
intrapeleural space expands
increase in negative pressure
what happens at exhalation?
diaphragm muscle relaxes
intrapleural space volume decreases
positive pressure
what are the functions of conducting airways?
- they allow air to enter / exit
-filter, warm and humidify inhaled air.
the epithelium is composed of several cell tpes
What is the function of the trachea?
cartilage rings on the outside for protection and to keep it open
what does the bronchi branch into?
bronchioles, they have no cartilage rings
what does the branchi do?
produces mucus to trap dirt particles and microorganisms
what are goblet cells?
The main role of goblet cells is to secrete mucus in order to protect the mucous membranes where they are found
what happens to the mucus produced by the bronchi?
it is continuously cleared by cilia to the pharynx and then swallowed
what is the pharynx
part of the throat
what is the respiratory conducting zone?
The conducting zone of the respiratory system is made up of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles; their function is to filter, warm, and moisten air and conduct it into the lungs.
what is the respiratory zone?
The respiratory zone is found deep inside the lungs and is made up of the respiratory bronchioles, alveolar ducts, and alveoli.
why does mucus not escape efficiently in smokers?
cillia are non functional in smokers, it would be flattened, so mucus cant escape effeciently
what is involved in the pulmonary circulation?
pulmonary artery and vein
how many alveoli are there in a lung?
what is their surface area
What is their radius and wall thickness?
about 500 million alveoli present
720m2 surface area
radiu = 0.1mm
wall thickness = 0.2 micrometers
what shape do alveoli take in alevolar sacs?
grape like clusters
what is the function of alveoli?
Alveoli is the primary site of gaseous exchange and passive diffusion.
how is effecient gas exchange guaranteed near between alveoli and bloo?
the alveolar wall is a single layer of epithelium cells.
the capillary wall is a single layer of endothelial cells
what do transport mechanisms do?
they allow O2 to enter the blood in the lungs and leave the blood in the tissues
what do erythrocytes contain?
they are red blood cells containing haemoglobin and carbonic anhydrase
what is haemoglobin?
an iron containing protein which transports oxygen
what does each subunit consist of in haemoglobin?
each subunit is a globular protein with an embedded haem group
colour of oxyhaemoglobin and deoxyhaemoglobin?
oxyhaemoglobin - bright red
deoxyhaemoglobin - bluish
what are carbonic anhydrases?
they are the fastest enzyme known, they dissolve CO2 in the plasma
how is CO2 transported?
dissolved in the plasma as BICARBONATE
Steps of gas exchange:
- inhalation - air move in from environment into alveoli
- O2 diffuses from alveoli to lung capillary
- 02 diffusess to red blood cells and binds to haemoglobin
- O2 disassociates from haemglobin and diffuses into tissue.
- Co2 diffuses from tissues to capillaries and is converted to HCO3- by red blood cells (erythrocyte)
- HCO3- travels in the plasma to the lung where it is converted back to CO2.
- diffusion of CO2 across lung capillary wall into alveoli
- exhalation - air moves into the environment.
what are alveolar macrophages (AMs)?
they are part of the immune system, they destroy pathogens
what do Alveolar Macrophages do?
they secrete cytokines to communicate with the rest of the immune system
what are cytokines?
any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells.
what is the pH in the cytosol of the AM?
basic, pH 7 - 7.4
what is the pH of the lysosome in the AM?
acidic, pH 4.5
how do lysosomes trap drugs in AMs?
if a basic drug is taken up through the cytosol and passes into the lysosome, it could get protonated due to acidic pH, preventing it from exiting the macrophage or the lysosme, so drug accumulates in the lysosome. destruction of macrophages could cause toxicity
what is asthma?
chronic inflammation of airways causing contraction of smooth muscles and narrowing of airways. mucus may also form in the airways
what are the causes of asthma?
family history, eczema and allergy, broncholitis, born prematurely, secondhand smoking, exposure to substances, hormones
types of asthma treatments:
long term control medications, quick relief medication, allergy medications
what disease does chronic obstructive pulmonary diseases include? what causes them?
emphysema, chronic bronchitis, mainly caused by smoking
what is caused by COPD?
inflamed airways, damaged airsacs, narrowing of airways, difficulty breathing
treatment for COPD?
stop smoking, eat well to prevent weight loss and infection, excercise, oxygen therapy, surgery, breathing machine
how do you guarantee rapid access to systemic circulation?
large surface area of lungs for instaneous absorption
does pulmounary absorption go through first pass metabolism?
no, local application at the desired site of action
what is a disadvantage of pulmonary absorption drug delivery?
only 2-10% aerosol deposited in lungs, 90% of dose is swalloed
name 2 delivery systems for pulmonary drug adminstration
nebuliser and metered dose inhaler, dry powder inhaler
how does a nebuliser work?
atomisation of liquid formulation into a mist of droplets for inhalation
when are nebulisers used?
used to give high doses of reliever medicine in severe asthma attacks in primary care
how does a metered dose inhaler work?
it releases aerosol of drug, designed to deliver a specific dose of medicine.
when is a metered dose inhaler used?
common for self adminstration of asthma and COPD
how does a dry powder inhaler work?
it is designed to deliver drug to lungs in dry powder particles, they rely on inhalation airflow to deliver drug (passive device)
