breathing and exchange of gases Flashcards
what does mechanisms of breathing depend upon
habitat and level of organisation
respiratory structure of sponges coelentratstes, flatworms
simple diffusion
respiratory structure of earthworms,
most cuticle
respiratory structure of insects
tracheal tubes
respiratory structure of aquatic arthropods, molluscs
gills
respiratory structure of terrestrial creatures
lungs
respiratory structure of fishes
gills
respiratory structure of amphibians, reptiles, birds, mammals
lungs
respiratory structure of tadpole of frog
Gills
respiratory structures of frog
buccal cavity, lungs, gills, moist skin
respiration through moist skin is called
cutaneous respiration
respiration through gills is called
branchial respiration
respiration through lungs is called
pulmonary respiration
what does the respiratory system contain
respiratory passage and respiratory organs
what does the respiratory passage contain
pair of nostrils, nasal cavity, a pair of internal nares, pharynx, larynx, trachea, bronchi, alveoli
what does the nasal chamber lead through
nasal passage
what does the nasal chamber open into
pharynx
what is the common passage for food and air
a portion of the pharynx
what does the Pharynx open into
larynx
what does the larynx region open into
trachea
what is the nature of larynx
cartilagenous box
what is larynx also called
sound box
what is glottis covered by during swallowing
epiglottis
describe structure and function of epiglottis
thin elastic cartilagenous flap that prevents entry of food in the larynx
where does trachea divide
at the level o of 5th thoracic vertebrae
division of the tracgea
left and right primary bronchi
what do the primary bronchi divide to form
secondary and tertiary bronchi
what do the secondary and tertiary bronchi divide to form
Bronchioles
what do the bronchioles divide to form
terminal bronchioles
what structures are supported by c-shaped incomplete cartilagenous rings
the tracheae, primary bronchi, secondary, tertiary, intial bronchioles,
what do the terminal bronchioles give rise to
thin irregular-walled, vascularized, bag like structures called alveoli
what is the respiratory surface of lungs
alveoli
what are the lungs covered by
double layered pleural membrane
the pleural membrane consists of
inner visceral membrane, outer parietal membrane
what is present in between the two membranes
pleural fluid
function of pleural fluid
reduces friction
what constitutes the conducting pathway of respiratory system
external nostrils to terminal bronchioles
function of conducting pathway
transports atmospheric air, filters the air, humidifies and brings air to body temperature
where does actual exchange of gases occur
alveoli
where are the lungs situated
thoracic chamber
describe the thoracic cavity
anatomically an air tight chamber
thoracic chamber is formed dorsally by
vertebral column
thoracic chamber is formed venetrally by
sternum
thoracic chamber is formed laterally hy
ribs
thoracic chamber is formed on the lower side by
diaphram
what does the anatomical setup of lungs in thorax ensure
that any change in the volume of the cavity will be refunded reflected in the pulmonary cavity
can we directly alter the pulmonary volume
no
what is trachea also called
wind pipe
structure and function of c shaped incomplete cartilagenous rings
hyaline cartilage, prevents the ducts from collapsing
how many alveoli are present in both lungs
300 million
how many alveoli are present in both lungs
300 million
what tissue are alveoli made up of
simple squamous epithelium
what is secreted by type 2 alveolar epithelial cells
Lecithin
function of lecithin
reduces surface tension, prevents collapsing of alveoli
what is the first step of pulmonary respiration
breathing through which co2 is exhaled and o2 is inhaled
what is the second step of pulmonary respiration
diffusion of gases across alveolar membrane
3rd step of respiration
transport of gases through blood
4th step of respiration
diffusion of gases between blood and tissues
5th step of respiration
utilisation of o2 for catabolic reactions
two step of breathing
inspiration, expiration
how is the mechanism of breathing carried out
by creating a pressure gradient
when does inspiration occur
when intra pulmonary pressure is less than the atmospheric pressure
when does expiration take place
when intra pulmonary pressure is more than atmospheric pressure
what organs help in creating the pressure gradient
diaphram, specialized set of external and internal intercostal muscles
how is inspiration initiated
contraction of diaphragm
change in volume during inspiration
increase in volume in the thoracic chamber in the antero posterior axis
external intercoastal muscles during inspiration; result
contract, lift up the ribs and cause increase in volume in dorso-ventral acis
during expiration, diaphragm
relaxes
during expiration, external intercoastal muscles
relaxes
what muscles help in forceful expiration
internal intercostal muscles and abdominal muscles
during forceful expiration, internal intercostal muscles
contract
during forceful expiration, abdominal muscles
contacts
breathing rate of a healthy human
12-16/min
what device helps in estimating volume of air in breathing movements
spirometer
what is respiratory volume
quantity of air our lungs can hold our expert under different conditions
what is tidal volume
volume of air inspired or expired during normal respiration
what is the value of tidal volume
500ml
how much can a healthy man inspire or expire
6000ml-8000ml / min
what is inspiratory reserve volume
additional volume of air a person can inspire by forceful inspiration
what is expiratory reserve volume
additional volume of air a person can expire under forceful expiration
value of inspiratory reserve volume
2500-3000ml/min
value of expiratory reserve volume
1000-1100ml/min
what is residual volume-
the volume of air present in the lungs even after a forceful expiration
value of residual volume-
1100ml-1200ml
what is inspiratory capacity
total volume of air a person can inspire after a normal expiration
what is included in inspiratory capacity
tidal volume IRV
what is expiratory capacity
total volume of air a person can expire after a normal inspiration
what is included in expiratory capacity
TV, ERV
what is functional residual capacity
total volume of air that will remain in the lungs after a normal expiration
what is included in FRC
ERV, RV
what is vital capacity
total volume of air a person can inspire after a forced expiration or risk volume of air a person can expire after a forced inspiration
what is included in VC
ERv IRV TV
what is total lung capacity
total volume of air in lungs after a forced inspiration
which volume cannot be determined by spirometer
residual volume-
what is partial pressure
pressure exerted by one gas in a mixture of gases
solubility o of co2 wrt to o2
20-25 times more soluble
what is the diffusion membrane composed of
thin squamous epithelium of alveoli, endothelium of blood vessels, basement substance
thickness of diffusion membrane
0.2-0.3 nanomenter thick
what is the primary site for exchange of gases
alveoli
what is the po2 in atmospheric air
159 per mmhg5
what is the po2 in alveoli
104 mmHg
what is the po2 in deoxygenated blood
40 mmHg
what is the po2 in oxygenated blood
95 mmHg
what is the po2 in tissues
40 mmHg
what is the po2 in expired air
1200
mmHg
what is the co2 in atmospheric air
0.3 mmHg
what is the co2 in alveoli
40 mmHg
what is the co2 in deoxygenated blood
45 mmHg
what is the co2 in oxygenated blood
40 mmHg
what is the co2 in tissues
45 mmHg
what is the co2 in expired air
27 mmHg
what percent of o2 is transported in dissolved form in plasma
3%
what percent of blood is carried by rbcs in blood
97%
describe haemoglobin
haem i is the iron part, globin is the protein part
what is formed by joining of haemoglobin and o2
oxyhaemoglobin
in what m manner does o2 bind with haemoglobin
reversible manner
how many molecules of o2 can one molecule of hemoglobin carry
4 molecules of o2
where does o2 bind with haemoglobin
lungs
where does o2 dissociate with haemoglobin
tissuee
how much is the haemoglobin level in a normal person
15 g in 100 ml of blood
capacity of 1g of hemoglobin to combine with o2 iis
1.34 ml
how much o2 does arterial blood transport
20 ml per 100 ml
how much o2 do venules transport
14.4 ml per 100 ml of blood
how muc o2 by blood is transported to tissues under normal condition
5ml
how much o2 is transported to tissue under strenuous conditions
15 ml per 20 ml
what is o2 dissociation graph
graph plotted against percentage saturation is hb with o2 and partial pressure of o2
what is the shape of o2 dissociation graph
sigmoid, s shape
where does dissociation of o2 occur/right shift
tissue
where does association of o2 occur/left shift
lungs
factors affecting dissociation of o2
low po2, High co2, high h+ concentration, high temperature
factors affecting association of o2
high po2, low co2, low h+ concentration, high H, low temperature
another factor affecting dissociation of o2
diphosphoglyceric acid(2,3DBG)
promotes dissociation
which has higher o2 affinity Hb-A, Hb-F
Hb-F
why does fetal haemoglobin have higher o2 affinity
it binds less strongly with Bipgosphoglyceric acid
what percent of co2 is transported in dissolved form
7% in blood plasma
what percentage of co2 is transported in the form of bicarbonate ions
70%
what enzyme facilitates the formation of carbonic acid and its breakdown
carbonic anhydrase
where is carbonic anhydrase found in high concentration
rbcs
where is carbonic anhydrase found in low concentration
plasma
where is co2 trapped as bicarbonate
tissue level
what percent of co2 is transported in the form of carbaminohaemoglobin
20-25%
what does co2 bind with in haemoglobin
the amino part of globin part of haemoglobin
factors that affect binding of haemoglobin with co2
in tissues, high pco2, in alveoli, low pco2
how much co2 is delievered to alveoli o per 100ml of blood
4ml
how long does inspiration last
2 seva
how long does expiration last
3 secs
how many times does an infant breath
44/min
what controls respiration
neural system
what is the function of respiratory rhythm centre
regulate respiratory rhythm
where is the pneumotaxic centre located
pons region of hind brain
function of pneumotaxic centre
sends neural signals to reduce duration of inspiration and alter respiratory rate
where is the chemosensitive area located
adjacent to rhythm centre
what is the chemosensitive area sensitive towards
rise in co2 and h+ ions
what receptors can recognise changes in co2 and h+ concentration
aortic arch and carotid artery receptors
whose role is quite insignificant in the regulation o of respiratory rhythm
oxygen
what is asthma
difficulty in breathing due to inflammation of bronchi and bronchioles
what causes asthma
allergens
symptoms of asthma
wheezing, coughing spasm of smooth muscles of bronchioles
what is emphysema
chronic disorder in which alveolar walls are damaged and respiratory surface is decreased
cause of emphysema
cigarette smoking
what is cause of occupational respiratory disorders
long exposure to fumes, dust, gases leads to proliferation of fibrous tissue
what is cause of occupational respiratory disorders
long exposure to fumes, dust, gases leads to proliferation of fibrous tissue
what are some occupational respiratory disorders
pneumonoconiosis
occupational respiratory disorders
silicosis, asbestosis