Question

The figures given below show diagrammatic cross sections of three kinds of blood vessels.
(a)Identify/ the blood vessels A, B and C.
(b)Name the parts labelled 1-4.
(c)Mention two structural differences between A and B.
(d)Name the kinds of blood that flow through A and through B respectively.
(e)In which one of the above vessels referred to in (a) above does the exchange of gases actually take place?

Answer 1

(a)
A represents Artery
B represents Vein
C represents Capillary
(b)
1 represents the External layer made of connective tissue
2 represents Lumen
3 represents the Middle layer of smooth muscles and elastic fibres
4 represents Endothelium
(c)
$\begin{array}{cc}\text{Arteries}\left(A\right)& \text{Veins}\left(B\right)\\ \begin{array}{c}\text{1. Progressively branched, decreasing in}\\ \text{size.}\end{array}& 1.\text{Progressively unite increasing in size.}\\ \text{2.}\text{Smallest artery breaks into arterioles.}& \text{2. Smallest vein arises from venules.}\\ \text{3. Have thick and more muscular walls.}& \text{3. Have thin and less muscular walls.}\end{array}$
(d)
Arteries A carry fully oxygenated blood and Veins B carry partially deoxygenated and $C{O}_2$ laden blood.
(e)
At the capillary level the actual exchange of gases takes place.