respiratory anatomy & physiology Flashcards
what is respiration
the exchange of gases between the tissues of the body and external environment
which two gasses does respiration involve and why
O2 - all cells require O2 to function
CO2 - waste product produced during metabolism
what is the first stage of respiration
air is alternately moved into and out of the lungs.
achieved by breathing (or ventilation)
what is the second stage of respiration
exchange of O2 and CO2 between air in lung and blood in capillaries
stage 3 of respiration
transport of O2 and CO2 by blood between the lungs and tissues
stage 4 of respiration
exchange of O2 and CO2 between blood and tissues
other than breathing what are other functions of respiratory system
- speech, singing etc
- water loss and heat elimination
- enhances venous return
- maintains acid base balance
- defends against inhaled foreign matter
- nose serves as the organ of smell
what stimulates taste and smell
G protein coupled receptors
what are the lungs divided into
several lobes (2 on left, 3 on right)
what occupies most of the volume of the thoracic (chest) cavity
the lungs
what separates the thoracic and abdominal cavity
the diaphragm
what is the conducting zone
all the structures that air must pass through to reach the lungs
what is the respiratory zone
the site where gas exchange actually occurs in the lungs
what happens in the conducting zone
air enters via the nose (or mouth) and is filtered, humidified and heated as it passes towards the lungs
what is the conuction zone useful for
saturating air and heating it up
characteristics of the conducting zone
tough, non muscular tube
has rings of cartilage to prevent collapse
is the conducting zone responsive to noradrenaline/adrenaline
no
does the conductive zone contract/expand
no
what is the bronchial tree
the respiratory zone
what are the branches of lungs from least branches to most
the trachea
the primary bronchus
the bronchial tree
terminal bronchioles
characteristics of small bronchioles
- show extensive branching pattern
- no cartilage to hold them open
- walls contain smooth muscle
- sensitive to certain hormones and local chemicals
what innervates the small bronchioles smooth muscle
the ans
can small bronchioles relax and contract
yes because they have no cartilage
what structures are in the respiratory zone
respiratory bronchioles and alveoli
what types of cells are in the respiratory zone
ciliated epithelial
what are the type I cells in respiratory zone
non-ciliated epithelium for gas exchange
what do type II cells in the respiratory zone do
supply surfactant which reduces surface tension and keeps alveoli complain
what do macrophages do
clear foreign particles
where are macrophages found
in the resp zone
columnar epithelial cells characteristics
they are ciliated and get rid of dust etc from lungs and move them to atmosphere
what do goblet cells do
they secrete mucous which can trap dust etc and break them down using glycoproteins
what is found in the resp epithelia
columnar epithelial cells
goblet cells
what is the respiratory epithelia needed for
mucosal barrier defence against pathogens.
mucocilary clearance of infectious agents.
are type one cells thick or thin
thin to allow for efficient gas exchange
what causes COPD
damage to alveoli
what are alveoli surrounded by
capillaries to maximise gas exchange
how many alveoli in each adult lung
several million
surface area of alveoli
70-90 metres squared
where do nerves that go to the skeletal muscle also go
to the diaphragm
is there ganglia as part of the parasympathetic system
yes
what does the parasympathetic system do in the bronchioles
direct innervations of the smooth muscle in the bronchioles
acetylcholine acts on muscarinic M3 receptors
CONTRACTION
what does the sympathetic system do in the lungs
indirect innervation
releases noradrenaline onto the a2 adrenoceptors on pre-ganglionic nerves
this causes reduction in acetylcholine release
adrenaline action in lungs
released from adrenal medulla
interacts with b2 adrenocepts on smooth muscle of bronchioles
RELAXATION
where does blood supply come from to the lungs
- tracheal arteries (from thyroid) and veins
- pulmonary artery (from heart to get oxygen and then pulmonary vein and then back to heart)
why is breathing easy
- lungs are compliant and elastic
- surfactant
- pleural membranes
what is lung tissue a mix of
smooth muscle
connective tissue
fibroblasts etc
why is there fluid at the bottom of the lungs
to dissolve oxygen and co2 but created an inward pressure (surfactant fights against)
how are lungs held open
by a positive transpulmonary pressure (Ptp)
what is required to dissolve gasses moving across type I cell types
moisture
what does inward pressure cause in the lungs
the alveoli are less able to expand during inspiration
causes the alveoli to collapse
what is surfactant
a phospholipid
what does surfactant do (in general not lungs)
gets in between water molecules and reduces the attraction between water molecules
where does surfactant work best in the lungs
in small alveoli
what does it do overall in lungs
prevents lung collapsing
prevents too much expansion
how does surfactant prevent too much expansion
as lungs expand detergent molecules get further apart
