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