Complete the missing terms
(a) Inspiratory Capacity (IC) $=\ldots+$ IRV
(b) $\ldots=\mathrm{TV}+\mathrm{ERV}$
(c) Functional Residual Capacity $(F R C)=E R V+\ldots$
(a) Inspiratory Capacity $(\mathrm{IC})=(\mathrm{TV})+(\mathrm{IRV})$ Tidal Volume. Inspiratory Reserve Volume
(b) Expiratory Capacity $(\mathrm{EC})=(\mathrm{TV}+\mathrm{ERV})$ Tidal Volume. Expiratory Reserve Volume
(c) Functional Residual Capacity $(F R C)=(E R V)$ Expiratory $+(R V)$ Reserve Volume. Residual Volume
Name the organs of respiration in the following organisms.
(a) Flatworm .............
(b) Birds ............
(c) Frog ............
(d) Cockroach $\qquad$
(a) Flatworm General body surface
(b) Birds Lungs
(c) Frog Lungs and moist skin
(d) Cockroach Tracheal tubes
The diaphragm and a specialised set of external and intercostals muscles between the ribs, help in the generation of pressure gradient during normal respiration.
Carbon dioxide is carried by the blood in three forms
(i) In Dissolved State Under normal temperature and pressure, about $7 \%$ of $\mathrm{CO}_2$ is carried by physical solution.
(ii) As Carbamino Compounds $\mathrm{CO}_2$ binds directly with Hb to form an unstable compound carbaminocompounds $\left(\mathrm{CO}_2 \mathrm{Hb}\right)$ About $23 \% \mathrm{CO}_2$ is transported in this form. When $\mathrm{pCO}_2$ is high and $\mathrm{pO}_2$ is low as in the tissues, more binding of carbon-dioxide occurs whereas, when $p \mathrm{CO}_2$ is low and $p \mathrm{O}_2$ is high as in alveol as tissue dissociation of $\mathrm{CO}_2$ from carbamino-haemoglobin takes place.
$$\mathrm{HbO}_2+\mathrm{CO}_2 \rightleftharpoons \mathrm{HbCO}_2+\mathrm{H}^{+}+\mathrm{O}_2$$
(iii) As Bicarbonate Ions $\mathrm{CO}_2$ reacts with water to form carbonic acid $\left(\mathrm{H}_2 \mathrm{CO}_3\right)$ in the presence of carbonic anhydrase in RBC. $\mathrm{H}_2 \mathrm{CO}_3$ dissociates into hydrogen and bicarbonate ions ( $\mathrm{HCO}_3{ }^{-}$).
The whole reaction proceeds as follows
$\mathrm{CO}_2+\mathrm{H}_2 \mathrm{O} \underset{\text { Anhydrase }}{\stackrel{\text { Carbonic }}{\rightleftharpoons}} \underset{\text { Carbonic acid }}{\mathrm{H}_2 \mathrm{CO}_3}$
$\underset{\text { Carbonic acid }}{\mathrm{H}_2 \mathrm{CO}_3} \rightleftharpoons \underset{\substack{\text { Hydrogen } \\ \text { ion }}}{\mathrm{H}^{+}}+\underset{\substack{\text { Bicarbonate } \\ \text { ion }}}{\mathrm{HCO}_3^{-}}$
The carbonic anhydrase reaction mainly occur in RBC as it contain high concentration of enzyme carbonic anhydrase and minute quantity of it is present in plasma too.