Breathing ncert Flashcards
O2 is utilised by the organisms to
——- break down nutrient molecules like —— and to derive energy
for performing various activities.
indirectly
glucose, aminoacids, fatty acids
Carbon dioxide which is harmful
is also released during the above —– reactions.
catabolic
The process of exchange of O2 from the —– with CO2 produced by the cells is called breathing,
commonly known as ——.
atmosphere
respiration
Mechanisms of breathing vary among different groups of animals
depending mainly on their —– and —–.
habitats, levels of organisation
Lower invertebrates like sponges, coelenterates, flatworms, etc., exchange O2 with CO2 by —-
simple diffusion over their entire body surface.
use their moist cuticle for exchange of gases.
Earthworms
insects have a network of tubes (—— tubes) to transport atmospheric air within the body.
tracheal
Special vascularised
structures called —– (branchial resp) are used by most of the aquatic arthropods and
—– whereas —— bags called lungs *pulmonary resp) are used by the terrestrial forms.
gills, molluscs
vascularised
Amphibians like frogs can respire through their —– also.
moist skin (cutaneous resp)
—- have a well developed respiratory system.
Mammals
We have a pair of external nostrils opening out above the——.
upper lips
It leads to a —– through the nasal passage.
nasal chamber
The nasal chamber opens into the pharynx, a portion of which is the —-passage for —- and —–
common
food and air
The pharynx opens through the —– region
into the trachea. —- is a cartilaginous box which helps in —–
production and hence called the sound box.
larynx
larynx
sound
During swallowing glottis
can be covered by a thin —————– called epiglottis to
prevent the —– into the larynx.
elastic cartilaginous flap
entry of food
Trachea is a straight tube
extending up to the —-cavity, which divides at the level of —– into a right and left primary bronchi.
mid-thoracic
5th thoracic vertebra
Each bronchi
undergoes repeated divisions to form the —- and —- bronchi
and bronchioles ending up in very thin —–bronchioles.
secondary and tertiary
terminal
The —— supported by incomplete cartilaginous rings.
trachea, primary, secondary and tertiary bronchi, and initial
bronchioles
Each terminal bronchiole gives rise to a number of very thin, —–walled
and vascularised bag-like structures called —–.
irregular
alveoli
The branching
network of —-, — and — comprise the lungs
bronchi, bronchioles and alveoli
We have two lungs which are covered by a double layered —–,
with —— between them.
pleura
pleural fluid
Pleural fluid reduces —- on the lung-surface.
friction
The outer pleural membrane is in close contact with the—-
whereas the inner pleural membrane is in contact with the —-
Thoracic cavity
Lung surface
The part starting with the —– up to the terminal
bronchioles constitute the —— part whereas the alveoli and their
—– form the respiratory or —- of the respiratory system.
external nostrils
conducting
ducts
exchange part
The conducting part transports the ——- to the alveoli, clears
it from —–, ——and also brings the air to body
temperature.
atmospheric air
foreign particles
humidifies
—— part is the site of actual diffusion of O2
and CO2
between blood and atmospheric air.
Exchange/ respiratory
The lungs are situated in the thoracic chamber which is anatomically
an —— chamber.
air-tight
The thoracic chamber is formed dorsally by the
———, ventrally by the ——-, laterally by the —-and on the lower side by the ——-.
vertebral column
sternum
ribs
dome-shaped diaphragm
The — setup of
lungs in thorax is such that any change in the volume of the thoracic
cavity will be reflected in the lung (pulmonary) cavity. Such an
arrangement is essential for breathing, as
anatomical
we cannot directly alter the
pulmonary volume
Respiration involves the following steps:
(i) Breathing or ——— by which atmospheric air
is drawn in and CO2
rich alveolar air is released out.
pulmonary ventilation
(ii) Diffusion of gases (O2
and CO2
) across ——–.
(iii) Transport of gases by the blood.
(iv) Diffusion of O2
and CO2
between blood and tissues.
alveolar membrane
v) Utilisation of O2
by the cells for ——- reactions and resultant
release of CO2
catabolic
Breathing involves two stages : ———-during which atmospheric
air is drawn in and ———by which the alveolar air is released out.
inspiration , expiration
The movement of air into and out of the lungs is carried out by creating a
———-between the lungs and the atmosphere.
pressure gradient
Inspiration
can occur if the pressure within the lungs (intra-pulmonary pressure) is
less than the atmospheric pressure, i.e., there is ——– pressure in
the lungs with respect to atmospheric pressure.
negative
The diaphragm and a specialised set of muscles –——- between the ribs, help in generation of such gradients.
external and
internal intercostals
Inspiration is initiated by the contraction of ——-which increases
the volume of ——– in the antero-posterior axis. The
contraction of ———- muscles lifts up the ribs and the — causing an increase in the volume of
the thoracic chamber in the dorso-ventral axis.
diaphragm,
thoracic chamber
external inter-costa
sternum l
The overall increase in the —- volume
causes a similar increase in pulmonary
volume.
thoracic
An increase in pulmonary volume
decreases the ——- pressure to less
than the – pressure which forces
the air from outside to move into the lungs,
i.e., inspiration
intra-pulmonary
atmospheric
Relaxation of
the diaphragm and the inter-costal muscles
returns the —– and —– to their
normal positions and reduce the thoracic
volume and thereby the pulmonary volume.
diaphragm
sternum
This leads to an increase in ——–
pressure to slightly above the —— pressure causing the expulsion of air from the lungs, i.e., —–
intra-pulmonary
atmospheric
expiration
We have the ability to ——the strength of
inspiration and expiration with the help of additional muscles in the ——
ncrease, abdomen
On an
average, a healthy human breathes —–
times/minute.
12-16
The volume of air involved in breathing movements can be estimated by using a —– which helps in clinical assessment of —— functions
spirometer
pulmonary
Tidal Volume (TV): Volume of air ———– during a normal respiration. It is
approx. – mL., i.e., a healthy man can
inspire or expire approximately ——-
mL of air per minute.
inspired or
expired
500
6000 to 8000mL/min
Inspiratory Reserve Volume (IRV):
—– volume of air, a person can inspire
by a ——– This averages 2500 mL to —mL.
Additional
forcible inspiration.
3000
————–:
Additional volume of air, a person can expire
by a forcible expiration. This averages ——- mL.
Expiratory Reserve Volume (ERV):
1000 mL to 1100
Residual Volume (RV): Volume of air remaining in the lungs even after a
——-. This averages ——- mL.
forcible expiration
1100 mL to 1200
By ——- respiratory volumes, one can
derive various pulmonary —-, which can be used in clinical diagnosis.
adding
capacities
Inspiratory Capacity (IC): Total volume of air a person can inspire after
——–. This includes ——–
volume
a normal expiration
tidal volume and inspiratory reserve ( TV+IRV).
: Total volume of air a person can expire after
a normal inspiration. This includes
Expiratory Capacity (EC):
tidal volume and expiratory reserve
volume (TV+ERV).
Volume of air that will remain in
the lungs after a normal expiration. This includes ERV+RV
Functional Residual Capacity (FRC):
Vital Capacity (VC): The maximum volume of air a ————
This includes—–
person can breathe in
after a forced expiration
ERV, TV and IRV .
Total Lung Capacity: Total volume of air accommodated in the lungs at
the end of —-
This includes ———- or
vital capacity + residual volume.
a forced inspiration.
RV, ERV, TV and IRV
Alveoli are the primary sites of ———-.
exchange of gases
Exchange of gases also
occur between —— and tissues.
blood
O2 and CO2 are exchanged in these
sites by———- mainly based on ——– gradient.
simple diffusion
pressure/concentration
—–of the gases as well as the —-of the membranes
involved in diffusion are also some important factors that can affect the
rate of diffusion.
Solubility
thickness
Pressure contributed by —- gas in a mixture of gases is called —- and is represented as pO2
for oxygen and pCO2
for carbon dioxide.
an individual, partial pressure
pO2 value indicates a concentration
gradient for oxygen from —– to —- and blood to tissues.
alveoli to blood
a gradient is present for CO2 in the opposite
direction of ___ , ie from —– to —- and
blood to alveoli.
O2
tissues to blood
As the solubility of CO2
is — higher than that of O2, the amount of CO2
that can diffuse through the diffusion membrane per ——– is much higher compared to that of O2
20-25 times
unit difference in partial pressure
The diffusion membrane is made up of — major layers namely, the thin ——- of alveoli, the —-of alveolar capillaries and the basement substance —–
three
squamous epithelium
endothelium
in between them
total thickness of alveolar membrane is much
less than a —-.
millimetre
Therefore, all the
factors in our body are —-for diffusion of O2 from —and that of CO2 from—-
favourable
alveoli to tissues
tissues to alveoli.
Blood is the medium of —for O2 and CO2
transport
About — per cent of O2
is transported by RBCs in the blood. The remaining —per cent of O2
is carried in a —-state through the plasma.
97, 3
dissolved
Nearly —— per cent of CO2 is transported by RBCs whereas 70 per cent of it is carried as —-.
20-25, carbonate
About 7 per cent of CO2
is carried in a dissolved state through —- .
plasma
Haemoglobin is a red coloured—–pigment present in the RBCs. O2
can bind with haemoglobin in a — manner to form
——-.
iron containing
reversible
oxyhaemoglobin
Each haemoglobin molecule can carry a maximum of
—- of O2
.
four molecules
Binding of oxygen with haemoglobin is primarily
related to —— of O2, Partial pressure of CO2, —— ion concentration and — are the other factors which can interfere with this binding
partial pressure
hydrogen
temperature
A —— curve is obtained when —- of haemoglobin with O2 is plotted against the pO2. This curve is called the ———- curve; highly useful in studying the—— like
pCO2, H+ concentration, etc., on binding of O2
with haemoglobin
sigmoid
percentage saturation
Oxygen dissociation
effect of factors
In the alveoli, where there
is – pO2, low pCO2
—H+ concentration
and —- temperature, the factors are all favourable for the formation of
—-.
high , lesser , lower
oxyhaemoglobin
In the —-, where low pO2, high pCO2, —- H+
concentration and higher temperature exist,
the conditions are favourable for —-
of oxygen from the oxyhaemoglobin.
tissues, high, dissociation
This clearly indicates that O2 gets bound to
haemoglobin in the —- and gets dissociated at the —-.
lung surface, tissues
Every 100 ml of
oxygenated blood can deliver around — of
O2 to the tissues under —
conditions.
5 ml
normal physiological
pO2 and pCO2 in:
1. Alveoli
2. Deoxygenated blood and tissues
3. Atmosphere
4. Oxygenated blood
- 104, 40
- 40, 45
-159, 0.3
-95, 40
CO2 is carried by haemoglobin as —- (about 20-25 per cent). This binding is related to the partial pressure of CO2. —-is a major factor which could affect this binding.
carbamino-haemoglobin
pO2
When pCO2 is high
and pO2 is low as in the —-, more — of carbon dioxide occurs
tissues, binding
RBCs contain
a very high concentration of the —-, carbonic anhydrase and —-
quantities of the same is present in the plasma too. This enzyme facilitates
reaction in —- directions.
enzyme, minute
both
Carbonic anhydrase causes —- reaction
co2+h2o to h2co3
and h2co3 to hco3- and h+
(Reverse also possible)
At the tissue site where partial pressure of CO2
is high due to
catabolism, CO2
diffuses into blood (RBCs and plasma) and forms –
and H+.
HCO3
At the — site where pCO2 is low, the reaction proceeds in the — direction leading to the formation of CO2
and H2O. Thus,
CO2 trapped as —- at the tissue level and transported to the alveoli is released out as CO2.
alveolar, opposite
bicarbonate
Every 100 ml of deoxygenated
blood delivers approximately —–
to the alveoli.
4 ml of CO2
Human beings have a significant ability to maintain and —- the
respiratory rhythm to suit the — of the body tissues. This is done by the —-
moderate, demands
neural system.
A specialised centre present in the —- region of the brain called respiratory rhythm centre is —- responsible for this regulation.
medulla, primarily
Another centre present in the pons region of the brain called —- centre can moderate the functions of the —-
pneumotaxic
respiratory rhythm centre.
Neural signal from respiratory rhythm centre can reduce the duration of — and thereby alter the —- rate.
inspiration
respiratory
A —– area
is situated adjacent to the rhythm centre which is highly sensitive to CO2
and hydrogen ions.
chemosensitive
Increase in H+ and CO2 can activate —- centre,
which in turn can signal the rhythm centre to make necessary adjustments in the respiratory process by which these substances can be —-.
Chemosensitive
eliminated
Receptors associated with —– and — can recognise
changes in CO2
and H+ concentration and send necessary signals to the
rhythm centre for remedial actions.
aortic arch and carotid artery
The role of oxygen in the regulation of
respiratory rhythm is —-
quite insignificant
—- is a difficulty in breathing causing wheezing due to —-
of bronchi and bronchioles.
Asthma
inflammation
Emphysema is a —-disorder in which —- are damaged due to which respiratory surface is decreased. One of the major causes of
this is —-
chronic
alveolar walls
cigarette smoking
Occupational respiratory disorder is seen in certain industries, especially those involving —– , so much dust is produced that the defense mechanism of the body cannot fully cope with the
situation.
grinding or stone-breaking
Long exposure can give rise to —- leading to fibrosis (—- of fibrous tissues) and thus causing serious lung damage.
inflammation
proliferation
Workers in stone breaking industries should wear
protective masks to prevent occupational respiratory disorder
