2. 1)N u t r i t i o n
2)N u t r i t i o n i n
pl a nt s
3) N u t r i t i o n i n
h u ma n s
4)R e s p i r a t i o n
6)T r a n s p o r t a t i o n
i n pl a nt s

3. Th
i n
u t
b o
nu
t h
o f
Au
He
i s
e p r o c e s s o f t a k i n g
f o o d a n d i t s
i l i z a t i o n b y t h e
d y i s c a l l e d
t r i t i on. Br o a d l y
e r e a r e t w o mo d e s
n u t r i t i o n –
t ot r ophi c a n d
t e r ot r ophi c . Fo o d
t h e ma t e r i a l

4. Th
c o
b o
i n
d i
l i
ma
b u
a n
me
nu
t h
e d i f f e r e n t
mp o n e n t s o f f o o d ,
t h o r g a n i c a n d
o r g a n i c , h a v i n g
s t i n c t f u n c t i o n s
k e p r o v i d i n g e n e r g y ,
t e r i a l s f o r b o d y
i l d i n g , ma i n t e n a n c e
d r e g u l a t i o n o f
t a b o l i s m a r e c a l l e d
t r i e nt s . Th e y a r e o f
r e e ma i n t y p e s :

5. Differences between autotrophs and
heterotrophs
He t e r o t r o p h
Au t o t r o p h
T
e
p
f
s
a
t
s
h
n
r
r
u
s
h
u
e y o b t a i n
e r g y b y
e p a r i n g f o o d
o m i n o r g a n i c
b s t a n c e s s u c h
C O 2 and w a t e r i n
e p r e s e n c e o f
n l i g h t .
These organisms are
called p r o d u c e r s as
t h e y ma n u f a c t u r e
t h e i r o wn f o o d .
T
e
c
s
c
o
h
n
o
u
o
r
Th
u t
ma
p r
t h
e y o b t a i n
e r g y f r o m
mp l e x o r g a n i c
b s t a n c e s b y
n s u mi n g p l a n t s
o t h e r a n i ma l s .
e
i
n
o
e
s
l
u
d
y
e o r g a n i s ms
i z e t h e f o o d
f a c t u r e d b y
u c e r s . He n c e ,
a r e c a l l e d

6. In unicellular organisms, since the entire cell
surface is in contact with the surroundings, the
food is obtained by d i f f u s i o n .
Ho we v e r , a s t h e
c o mp l e x i t y l e v e l
i n c r e a s e s , s p e c i a l i z e d
p a r t s a r e e v o l v e d t o
p e r f o r m t h i s f u n c t i o n .
Nutrition in Amoeba: Amoeba consumes food
with the help of p s e u d o p o d i a .
Ps e u d o p o d i a a r e
t e m p o r a r y f i n g e r -l i k e
p r o j e c t i o n s o f t h e
c e l l s u r f a c e , wh i c h
f u s e o v e r t h e f o o d
p a r t i c l e . Th i s r e s u l t s

7. Nu t r i t i o n
i n Paramecium: In Paramecium, food i s
i n g e s t e d t h r o u g h a
d e f i n i t e c e l l mo u t h . T h e
c i l i a p r e s e n t a l l o v e r
t h e b o d y mo v e
c o n t i n u o u s l y t o p u s h
t h e f o o d p a r t i c l e s
a l o n g t h e wa t e r c u r r e n t .
Th e f o o d e n t e r i n g
i n s i d e c o l l e c t s t o f o r m
a f o o d v a c u o l e .
Di g e s t i o n o f f o o d

8. T h e process of taking in a source of
energy (food) from outside the body of
an organism to inside is known
as n u t r i t i o n . P l a n t s
h a v e a n autotrophic mode o f
nut r i t i on. I n t hi s
mo d e o f n u t r i t i o n ,
plants prepare or synthesize their own
food with the help of inorganic raw
materials. Thus, they are known

9. Photosynthesis
Au t o t r o p h s s u c h a s
g r e e n p l a n t s a n d s o me
b a c t e r i a p r e p a r e o r
synthesize their own food. They are capable of
trapping solar energy with the help of a green
pigment called chlorophyll. T h i s
t r a p p e d s o l a r e n e r g y
i s t h e n c o n v e r t e d i n t o
c h e mi c a l e n e r g y o f
f o o d u s i n g C O 2 and H 2O .
Photosynthesis is t h e p r o c e s s b y

10. 
Sunlight

12. Ent r y of r a w
ma t e r i a l s
Plants obtain water through their roots.
Water is then transported to all plant
parts with the help of the x y l e m .
Ex c h a n g e o f g a s e s
(e n t r y o f C O 2 and
r e l e a s e o f O 2)
o c c u r s t h r o u g h t h e

13. S t o m a t a are t i n y p o r e s
p r e s e n t ma i n l y o n
t h e s u r f a c e o f
l e a v e s . Th e y a r e
a l s o p r e s e n t o n t h e
s u r f a c e o f y o u n g
s t e ms a n d r o o t s .
S t o ma t a c o n s i s t o f a
s t o m a t a l opening or stoma,
which is surrounded by two distinct
epidermal cells known as g u a r d
c e l l s . Th e o p p o s i n g

14. Opening and closing of
stomata
T
o
t
t
t
t
a
l
c
h
f
h
h
h
u
n
o
l
e ope n
s t o ma
e t ur g
e gua r
e gua r
r gi d, t
d wh e n
s e wa t
os e s .
i ng a nd c l os i ng
t a de pe nds upon
or pr e s s ur e i n
d c e l l s . Wh e n
d c e l l s a r e
h e s t o ma o p e n s
t he gua r d c e l l s
e r , s t o ma

15. T h e f o l l o wi n g e v
o c c u r d u r i n g t h i
p r o c e s s –
(i ) A b s o r p t i o n o f
e n e r g y b y
c h l o r o p h y l l .
(i i ) C o n v e r s i o n o
e n e r g y t o c h e mi c
e n e r g y a n d s p l i t
w a t e r mo l e c u l e s
e n t s
s
l i g h t
f l i g h t
a l
t i n g o f

16. Two phases of
photosynthesis
The
two
r e
r e
Li
t h
t h
t a
p r
process of photosynthesis occurs in
phases – the l i g h t
a c t i o n s and the d a r k
a c t i ons .
g h t r e a c t i o n s – As
e n a me s u g g e s t s ,
i s r e a c t i o n
k e s p l a c e i n t h e
e s e n c e o f l i g h t .

17. Ad d i t i o n a l l y i n
p h a s e , a s s i mi l a t
p o we r i n t h e f o r
A T P a n d N A D P H 2 are
p r o d u c e d .
L i g h t r e a c t i o n s
o c c u r i n t h e
me mb r a n e s o f
t h y l a k o i d s .
Ev e nt s oc c ur r i n
dur i ng l i ght
r e a c t i ons :
A b s o r p t i o n o f l
e n e r g y b y
t h i s
o r y
m o f
g
i g h t

18. Da
r e
r e
a n
s t
c h
t h
NA
l i
u t
r e
c a
r k r e a c t i ons – Th i s
a c t i o n d o e s n o t
q u i r e d i r e c t l i g h t
d o c c u r s i n t h e
r o ma o f
l o r o p l a s t s . Du r i n g
i s p h a s e , ATP a n d
D P H 2 (f o r m e d d u r i n g
g h t r e a c t i o n s ) a r e
i l i z e d f o r t h e
d u c t i o n o f C O 2 to
r b o h y d r a t e s (f o o d ).

19. H u ma n b e i n g s c a n n o t
p r o d u c e t h e i r o wn f o o d
t h u s , their mode of nutrition
is h e t e r o t r o p h i c . I n
t h i s mo d e o f n u t r i t i o n ,
o r g a n i s ms o b t a i n
energy from the intake of complex organic
substances, generally from plant and animal
sources. These organisms are known
as h e t e r o t r o p h s . A l l

20. It is by the process
of d i g e s t i o n that t h e
n u t r i e n t s p r e s e n t i n
f o o d a r e u t i l i z e d b y
t h e h u ma n b o d y .
D i g e s t i o n ma y t h u s
b e d e f i n e d a s t h e
me c h a n i c a l a n d
c h e mi c a l r e d u c t i o n
o f i n g e s t e d
n u t r i e n t s f i r s t i n t o
p a r t i c l e s , t h e n i n t o

22. Digestive organs and their
functions
(i) Mouth: D i g e s t i o n o f f o o d
b e g i n s i n t h e mo u t h . T h e
mo u t h c o mp r i s e s o f t h e
f o l l o wi n g :
Te e t h: Th e y t e a r a n d
b r e a k d o wn t h e f o o d .
Sa l i v a : I t c o n t a i n s a
d i g e s t i v e e n z y me c a l l e d
s a l i v a r y a my l a s e , w h i c h
b r e a k s d o wn s t a r c h i n t o
s u g a r .
Tongue : I t i s a s e n s e

25. (i i ) P h a r y n x : It i s a
c o mmo n p a s s a g e w a y
f o r f o o d a n d a i r . I t
o p e n s i n t o t h e
o e s o p h a g u s (w h i c h
l e a d s t o t h e
s t o ma c h ) a n d
t r a c h e a (w h i c h
l e a d s t o t h e l u n g s ).

26. (i i i ) O e s o p h a g u s : The
c i r c u l a r s mo o t h
mu s c l e s i n t h e
o e s o p h a g u s c o n t r a c t
wh e n f o o d i s
s wa l l o we d . T h i s
p r e v e n t s t h e c h e we d
f o o d ma t e r i a l f r o m
mo v i n g b a c k i n t o t h e
mo u t h . T h i s i s
f o l l o we d b y t h e
c o n t r a c t i o n s a n d
r e l a x a t i o n s o f t h e

27. Pe r i s t a l s i s

28. (i v ) S t o m a c h : The s t o m a c h
s t o r e s a n d mi x e s t h e
f o o d r e c e i v e d f r o m
t h e o e s o p h a g u s wi t h
t h e g a s t r i c j u i c e . Th e
g a s t r i c g l a n d s
p r e s e n t i n t h e wa l l s
o f t h e s t o ma c h
s e c r e t e s e v e r a l
s u b s t a n c e s , wh i c h
t o g e t h e r c o n s t i t u t e
t h e g a s t r i c j u i c e .

29. Ac
Ex
h y
t h
d a
p r
t h
So
b e
o e
i di t y :
c e s s p r o d u c t i
d r o c h l o r i c a c
e s t o ma c h c a n
ma g e t h e
o t e c t i v e l i n i
e s t o ma c h .
me t i me s , t h e v
t we e n t h e
s o p h a g u s a n d
o n o f
i d i n
n g o f
a l v e

30. Th e f o o d f r o m t h e
s t o ma c h p a s s e s i n t o
t h e s ma l l i n t e s t i n e .
(v ) S m a l l i n t e s t i n e : It
i s t h e l o n g e s t p a r t o f
t h e a l i me n t a r y c a n a l .
I t i s ma d e u p o f t h r e e
p a r t s - d u o d e n u m,
j e j u n u m, a n d i l e u m.
Th e l e n g t h o f t h e
s ma l l i n t e s t i n e

31. T h e s ma l l i n t e s t i n e
p r o d u c e s i n t e s t i n a l j u i c e
f r o m t h e g l a n d s p r e s e n t i n
t h e wa l l , wh i c h h e l p s i n
f u r t h e r d i g e s t i o n o f f o o d .
Digestive juices from two glands, namely the liver and
pancreas m i x e s w i t h t h e f o o d i n
t h e s ma l l i n t e s t i n e .
The liver produces b i l e j u i c e (which causes
emulsification of fats) and
the p a n c r e a s produces p a n c r e a t i c
j u i c e (f o r d i g e s t i n g
p r o t e i n s a n d e mu l s i f i e d

33. Th i s d i g e s t e d f o o d i s t h e n
a b s o r b e d t h r o u g h t h e
intestinal walls. The inner lining of the small intestine
has millions of tiny finger-like projections called
the v i l l i . T h e s e p r o j e c t i o n s
i n c r e a s e t h e s u r f a c e a r e a
o f t h e s ma l l i n t e s t i n e f o r
mo r e e f f i c i e n t f o o d
a b s o r p t i o n .
Wi t h i n t h e s e v i l l i , t h e
c a p i l l a r i e s a b s o r b
n u t r i e n t s f r o m t h e
d i g e s t e d p r o d u c t s o f
p r o t e i n s a n d

34. (v i ) L a r g e i n t e s t i n e : The
i n d i g e s t i b l e
ma t e r i a l a n d w a t e r
e n t e r s t h e l a r g e
i n t e s t i n e . I t a l s o h a s
v i l l i t o a b s o r b wa t e r
a n d s o me v i t a mi n s
f r o m t h e u n d i g e s t e d
f o o d . Th i s a b s o r p t i o n
o f wa t e r h e l p s t o
c o mp a c t t h e f a e c e s . I t

35. Re
bo
i n
e x
p r
o x
c a
p r
c o
o x
s
d
h
h
o
y
r
o
n
y
p
i
a
a
c
g
b
c
s
g
i
l
l
l
e
e
o
e
u
e
r a t i on i s t he
y pr oc e s s of
a t i on a nd
a t i on. I t i s t h e
s s o f t a k i n g i n
n a n d r e l e a s i n g
n d i o x i d e . Th e
s s i n v o l v e s t h e
mp t i o n o f
n a n d

36. 

37. Re s p i r a t i o n c a n o c c u r b o t h
i n t h e p r e s e n c e a n d
a b s e n c e o f O 2. On this basis, it can be
classified b i ctwo types: a e r n a ei r co b i nc d
a
A e r o into
Ao b
pi o b
r e s pi r a t i on
a rneas e r r a t i i co .n
I
t
o
I
t
o
b
o
o
e
t
h
f
t
h
f
e
r
u
n
o c c u r s i n
e p r e s e n c e
O 2.
i n v o l v e s
e e x c h a n g e
g a s e s
t we e n a n
g a n i s m a n d
t s i d e
v i r o n me n t .
I
t
o
E
g
a
t
h
f
x
a
b
o c c u r s i n
e a b s e n c e
O 2.
c h a n g e o f
s e s i s
s e n t .

38. Glucose is the simplest molecule that enters a
series of reactions
called G l y c o l y s i s and the K r e b s
c y c l e to p r o d u c e e n e r g y .
Pr o t e i n s a n d f a t t y
a c i d s a r e b r o k e n d o wn
a n d e n t e r t h e c y c l e a t
d i f f e r e n t r e g i o n s .
A mi n o a c i d s , d e p e n d i n g
u p o n t h e l e n g t h o f t h e
c a r b o n c h a i n , e n t e r t h e
Kr e b s c y c l e a t
d i f f e r e n t p l a c e s .

39. Aerobic respiration: I t i n v o l v e s
f o u r ma i n s t e p s :
Step 1: The first step is
called g l y c o l y s i s . I t o c c u r s
i n t h e c y t o p l a s m o f a
c e l l . I t d o e s n o t r e q u i r e
o x y g e n . H e r e , t h e 6-c a r b o n
mo l e c u l e g l u c o s e i s
p a r t i a l l y b r o k e n d o wn
i n t o a 3-c a r b o n m o l e c u l e ,
p y r u v a t e o r p y r u v i c a c i d .
I n t h i s s t e p , o n e g l u c o s e
mo l e c u l e p r o d u c e s 2
mo l e c u l e s o f p y r u v a t e .
Glucose 2 P y r u v a t e
Step 2: T h e t w o p y r u v i c a c i d
mo l e c u l e s a r e c o n v e r t e d
i n t o a c e t y l Co A, wh i c h
c a n e a s i l y e n t e r t h e
mi t o c h o n d r i a , w h i c h i s
t h e s i t e f o r f u r t h e r
r e a c t i o n s .
S t e p 3: These a c e t y l C o A

40. 
In absence
Wa s t e

41. An a e r o b i c r e s p i r a t i o n
o c c u r s i n t h e r o o t s o f s o me
s p e c i e s o f wa t e r l o g g e d
p l a n t s , p a r a s i t i c w o r ms ,
y e a s t , a n i ma l mu s c l e s , a n d
mi c r o o r g a n i s ms .
In some microorganisms such as yeasts, anaerobic
respiration is called f e r m e n t a t i o n . I n
t h e p r o c e s s o f
f e r me n t a t i o n , e t h a n o l i s
f o r m e d a s a b y -p r o d u c t .

42. Respiration in humans
T h e h u ma n r e s p i r a t o r y
s y s t e m supplies o u r b o d y w i t h
O 2 and a l s o h e l p s i n r e m o v i n g
C O 2, which i s a w a s t e p r o d u c t
f o r me d d u r i n g c e l l u l a r
r e s p i r a t i o n . Th e i n t a k e o f
O 2 and e x i t o f C O 2i n v o l v e s
t wo p r o c e s s e s :

43. 1) Inhalation: I t i n v o l v e s
b r i n g i n g i n a i r f r o m
o u t s i d e t h e b o d y i n t o t h e
l u n g s . Wh e n w e b r e a t h e i n ,
t h e s i z e o f o u r c h e s t
i n c r e a s e s .
T h i s h a p p e n s b e c a u s e wh e n
a i r e n t e r s , t h e l u n g s
e x p a n d a n d t h e r i b s mo v e
o u t w a r d s . S i mu l t a n e o u s l y ,
t h e d i a p h r a g m c o n t r a c t s
a n d b e c o me s f l a t . T h u s , t h e
s i z e o f o u r c h e s t
i n c r e a s e s .

44. Organs involved in
respiration:
The organs of the respiratory system extend from the nose to
lungs. They include the n o s e , p h a r y n x ,
t r a c he a , br onc hi , a nd
br onc hi ol e s .
1) N o s t r i l s : The a i r f r o m o u t s i d e
f i r s t e n t e r s t h e n o s t r i l s ,
which is divided into the left and the right nostril. These
nostrils lead to open spaces in the nose called the n a s a l
pa s s a ge . Th i s p a s s a g e c o n t a i n s
h a i r a n d mu c u s , w h i c h p e r f o r m
t h e f u n c t i o n s o f f i l t e r i n g ,
mo i s t e n i n g , a n d w a r mi n g t h e
a i r e n t e r i n g t h e n a s a l

45. 3) Larynx: The air from the pharynx enters
the larynx or voice b o x . I t c o n t a i n s
t wo t r u e v o c a l c o r d s , wh i c h
a r e ma d e u p o f c a r t i l a g e
a n d f i b r e s . Wh e n a i r p a s s e s
t h r o u g h t h i s a r e a , t h e
v o c a l c o r d s v i b r a t e a n d
t h i s p r o d u c e s d i f f e r e n t
s o u n d s . H u ma n b e i n g s c a n
c o n t r o l t h i s v i b r a t i o n .
T h u s , t h e y c a n ma k e v a r i o u s
s o u n d s a n d a r e c a p a b l e o f
s p e e c h .
4) Trachea: From the larynx, the inhaled air moves into
the wind pipe or trachea.
Th e t r a c h e a i s a l o n g

47. Ex c h a n g e o f
g a s e s i n
r e s p i r a t i o n
Wh e n w e b r e a t h e
i n , we t a k e i n
O 2, w h i c h r e a c h e s
t h e l u n g a l v e o l i .
O 2 then d i f f u s e s
i n t o b l o o d o f t h e
s u r r o u n d i n g
c a p i l l a r i e s f r o m
t h e a l v e o l i ,
wh i c h h a s a h i g h
c o n c e n t r a t i o n o f
O 2. T h e
h a e mo g l o b i n
p i g me n t p r e s e n t

48. A f t e r s u p p l y i n g O 2 to t h e b o d y
c e l l s , t h e b l o o d c o l l e c t s
C O 2, which i s p r o d u c e d a f t e r
c e l l u l a r r e s p i r a t i o n i n t h e
c e l l s . T h u s , t h e b l o o d b e c o me s
d e o x y g e n a t e d .
T h e h a e mo g l o b i n p i g me n t h a s
l e s s a f f i n i t y f o r C O 2.
T h e r e f o r e , i t i s ma i n l y
t r a n s p o r t e d i n t h e d i s s o l v e d
f o r m. T h i s d e o x y g e n a t e d b l o o d
b r i n g s b a c k C O 2 to l u n g a l v e o l i .
Th e l u n g s h a v e a h i g h
c o n c e n t r a t i o n o f O 2.
Th e r e f o r e , i t d i f f u s e s i n t o

49. Th e t r a n s p o r t a t i o n s y s t e m i n
p l a n t s mo v e s t h e e n e r g y s t o r e d
i n l e a v e s t o d i f f e r e n t p a r t s .
I t a l s o h e l p s i n mo v i n g r a w
ma t e r i a l s a b s o r b e d f r o m t h e
r o o t s t o v a r i o u s o r g a n s o f t h e
p l a n t . Ho we v e r , t h e s e a r e
e n t i r e l y d i f f e r e n t p a t h wa y s .
Th e t r a n s p o r t a t i o n s y s t e m i n
p l a n t s c o n s i s t s o f t wo
d i f f e r e n t t y p e s o f c o n d u c t i n g
t i s s u e s .
Xy l e m c o n d u c t s wa t e r a n d
mi n e r a l s o b t a i n e d f r o m s o i l
(v i a r o o t s ) t o t h e r e s t o f t h e
p l a n t . Ph l o e m t r a n s p o r t s f o o d

50. Transport of water
Co
t i
v e
a n
i n
c o
wa
wh
t h
Ro
mi
s o
s u
f i
t o
mp o n e n t s o f t h e x y l e m
s s u e (t r a c h e i d a n d
s s e l s ) o f r o o t s , s t e ms ,
d l e a v e s a r e
t e r c o n n e c t e d t o f o r m a
n t i n u o u s s y s t e m o f
t e r -c o n d u c t i n g c h a n n e l s ,
i c h r e a c h e s a l l p a r t s o f
e p l a n t .
o t s a b s o r b wa t e r a n d
n e r a l s a l t s f r o m t h e
i l . Ea c h s o i l p a r t i c l e i s
r r o u n d e d b y a c o n t i n u o u s
l m o f wa t e r , l o o s e l y h e l d
i t b y a f o r c e k n o wn a s

51. Th
a r
b e
s u
t h
t h
i n
t h
p a
c o
wh
c e
a c
i s
wa
c r
e c e l l s i n t h e r o o t h a i r
e d e f i c i e n t i n wa t e r
c a u s e t h e y c o n t i n u o u s l y
p p l y t h e a b s o r b e d wa t e r t o
e s t e ms a n d l e a v e s . T h u s ,
e c o n c e n t r a t i o n o f wa t e r
t h e r o o t h a i r i s l e s s t h a n
e wa t e r p r e s e n t i n s o i l
r t i c l e s . Th i s c r e a t e s a
n c e n t r a t i o n g r a d i e n t ,
i c h a l l o ws t h e r o o t h a i r
l l s t o u p t a k e wa t e r
t i v e l y . As a r e s u l t , t h e r e
a s t e a d y mo v e me n t o f
t e r i n t o t h e r o o t x y l e m
e a t i n g a c o l u mn o f w a t e r ,

52. Transportation of food
The transportation of food from the leaves to other
parts of the plant occurs in the vascular tissue, namely
the p h l o e m . This process of transporting food is
known as t r a n s l o c a t i o n . T h e
p h l o e m a l s o t r a n s p o r t s
a mi n o a c i d s a n d o t h e r
s u b s t a n c e s t o s t o r a g e
o r g a n s o f t h e p l a n t (a l o n g
wi t h t h e g r o wi n g o r g a n s )
s u c h a s r o o t s , f r u i t s , a n d
s e e d s . Th e p h l o e m c o n s i s t s
o f c o mp a n i o n c e l l s , s i e v e

53. The system that transports nutrients and collects waste
materials for disposal in the body is
the c i r c u l a t o r y s y s t e m . T h e
c i r c u l a t o r y s y s t e m
consists of the central organ i.e., the heart, blood
vessels, and circulating fluid i.e., blood. Another
system, called the l y m p h a t i c
s y s t e m , transports i m m u n e c e l l s .

54. Blood vessels
Ar t e r i e s a r e t o u g h , e l a s t i c
t u b e s t h a t c a r r y b l o o d f r o m
t h e h e a r t a n d s u p p l y i t t o
v a r i o u s o r g a n s o f t h e b o d y .
A s t h e a r t e r i e s mo v e a w a y
from the heart (i.e., on reaching organs and tissues), they
divide into smaller vessels. The smallest vessels
called capillaries h a v e v e r y t h i n w a l l s .
Ar t e r i e s a r e r e d i n c o l o r
b e c a u s e t h e y c a r r y
o x y g e n a t e d b l o o d .

55. Ca
t i
f o
b l
o r
a r
c o
i s
b l
t h
l o
Th
p i l l a r i e s (i n o r g a n s a n d
s s u e s ) j o i n t o g e t h e r t o
r m v e i n s . Ve i n s c o l l e c t
o o d f r o m d i f f e r e n t
g a n s a n d t i s s u e s . Ve i n s
e t h i n -w a l l e d a s
mp a r e d t o a r t e r i e s . T h i s
b e c a u s e t h e y b r i n g b a c k
o o d f r o m t h e o r g a n s t o
e h e a r t a n d b l o o d i s n o
n g e r u n d e r p r e s s u r e .
e s e v e i n s c a r r y

56. B
r
b
P
l
e
l
l
Components of blood:
o
d
o
a
o d c o n
b l o o d
o d c e l
s ma : B l
s i s t s o f p l a s ma ,
c e l l s , wh i t e
l s , a n d p l a t e l e t s .
o o d plasma is the strawcolored/pale-yellow liquid component of blood that normally
holds the blood cells in whole
blood in s u s p e n s i o n .
Re d b l o o d c e l l s : Re d b l o o d
c e l l s , or e r y t h r o c y t e s , are the most
common type of blood cell and the v e r t e b r a t e
o r g a n i s m 's principal means of
delivering oxygen (O 2) to the body tissues via the blood flow

57. Wh i t e b l o o d
c e l l s (l e u k o c
y t e s ): a r e cells of
the immune system involved
i n d e f e n d i n g
t h e b o d y
a g a i n s t b o t h
i n f e c t i o u s
disease and f o r e i g n
ma t e r i a l s .
Pl a t e l e t s
(t h r o m b o c y t e s
): a r e s m a l l ,
d i s k s h a p e d
c l e a r c e l l
f r a g m e n t s which

58. Heart
I n h u ma n b e i n g s , t h e h e a r t
i s a mu s c u l a r o r g a n . I t i s
d i v i d e d i n t o f o u r
c h a mb e r s – r i g h t a u r i c l e ,
right ventricle, left auricle, and left ventricle. The
walls of these chambers are made up of a special
muscle called m y o c a r d i u m , w h i c h
c o n t r a c t s c o n t i n u o u s l y
a n d r h y t h mi c a l l y t o
d i s t r i b u t e b l o o d t o a l l
t h e b o d y c e l l s .

59. Flow of blood in the human
heart
T
a
T
b
l
b
s
b
a
h
n
h
l
o
o
u
l
u
e h e a r
d i n f e
e y c a r
o o d f r
we r r e
d y r e s
p p l y t
o o d t o
r i c l e
t h a s s u p e r i o r
r i o r v e n a c a v a .
r y d e o x y g e n a t e d
o m t h e u p p e r a n d
g i o n s o f t h e
p e c t i v e l y a n d
h e d e o x y g e n a t e d
t h e r i g h t
o f t h e h e a r t .

60. Th e r i g h t a u r i c l e c o n t r a c t s
a n d p a s s e s t h e d e o x y g e n a t e d
b l o o d t o t h e r i g h t v e n t r i c l e ,
t h r o u g h a n a u r i c u l o v e n t r i c u l a r a p e r t u r e
(t r i c u s p i d v a l v e ).
Th e r i g h t v e n t r i c l e c o n t r a c t s
a n d p a s s e s t h e d e o x y g e n a t e d
b l o o d i n t o t h e t w o p u l mo n a r y
a r t e r i e s , w h i c h p u mp s i t t o
t h e l u n g s wh e r e t h e b l o o d i s
o x y g e n a t e d . Fr o m t h e l u n g s ,
t h e p u l mo n a r y v e i n s t r a n s p o r t
t h e o x y g e n a t e d b l o o d t o t h e
l e f t a t r i u m o f t h e h e a r t . Th u s ,
i n f i s h e s , t h e b l o o d p a s s e s

61. Lymphatic system
L
c
h
t
I
v
c
v
p
t
t
y
o
e
r
n
e
o
e
r
h
h
mp h i s a n o t h e r f l u i d
n n e c t i v e t i s s u e , wh i c h
l p s i n t h e p r o c e s s o f
a n s p o r t a t i o n .
a d d i t i o n t o b l o o d
s s e l s , t h e b o d y
n t a i n s l y mp h a t i c
s s e l s . S o me p o r e s a r e
e s e n t i n t h e wa l l s o f
e c a p i l l a r i e s a n d
r o u g h t h e s e p o r e s ,

62. This forms the t i s s u e
f l u i d or l y m p h . I t i s a
c o l o r l e s s f l u i d t h a t
c o n t a i n s l e s s p r o t e i n .
T h e l y mp h e n t e r s i n t o
t i n y v e s s e l s s i t u a t e d
i n i n t e r c e l l u l a r
s p a c e s . Th e s e
c a p i l l a r i e s j o i n t o
f o r m t h e l y mp h
v e s s e l s .

63. Func t i ons of t he
l y mp h :
I t a c t s a s a
r e s e r v o i r o f wa t e r ,
s a l t s , a n d d i g e s t e d
f o o d .
I t c a r r i e s d i g e s t e d
f o o d a n d f a t s f r o m
t h e s ma l l i n t e s t i n e .
L y mp h a t i c v e s s e l s
p r e s e n t i n t h e
i n t e s t i n a l v i l l i

64. T
e
s
o
k
o
u
a
T
i
p
u
t
h
x
y
f
i
f
r
n
h
n
a
r
h
e h u ma n
c r e t o r y
s t e m c o n s i s t s
a p a i r o f
d n e y s , a p a i r
u r e t e r s , a
i n a r y b l a d d e r ,
d a u r e t h r a .
e u r i n e f o r me d
t h e k i d n e y s ,
s s e s i n t o t h e
i n a r y b l a d d e r
r o u g h t h e

65. Functions of kidneys
Th
n i
t h
i n
b a
r e
Th
wa
a c
f r
k i
e y e l i mi n a t e
t r o g e n o u s wa s t e s f r o m
e b o d y a n d a r e h e l p f u l
ma i n t a i n i n g t h e w a t e r
l a n c e o f t h e b o d y b y
mo v i n g e x c e s s f l u i d s .
e v a r i o u s n i t r o g e n o u s
s t e s s u c h a s u r e a , u r i c
i d e t c . a r e s u p p l i e d
o m t h e b l o o d t o t h e
d n e y s (t h i s i s s i m i l a r

66. Th e k i d n e y s c o n s i s t o f
a c l u s t e r o f v e r y t h i n wa l l e d c a p i l l a r i e s .
Ea c h c l u s t e r i s
a s s o c i a t e d wi t h a c u p shaped end of a tube, in which filtered urine
is collected. These basic filtering units of the
kidneys are called n e p h r o n s .
Ea c h k i d n e y p o s s e s s e s
a l a r g e n u mb e r o f
n e p h r o n s
(a p p r o x i m a t e l y 1- 1.5
m i l l i o n ).

67. The main components of a
nephron are
the g l o m e r u l u s ,
B o w m a n ’s
c a p s u l e , and a
long r e n a l t u b e .
Th e b l o o d
e n t e r s t h e
k i d n e y s
t h r o u g h t h e
r e n a l a r t e r y ,
wh i c h
b r a n c h e s i n t o
ma n y

68. I n t h e p r o x i ma l t u b u l e ,
s o me s u b s t a n c e s s u c h a s
a mi n o a c i d s , g l u c o s e , a n d
s a l t s a r e s e l e c t i v e l y
r e a b s o r b e d a n d u n wa n t e d
mo l e c u l e s a r e a d d e d i n t h e
u r i n e . Th e f i l t r a t e t h e n
mo v e s d o w n i n t o t h e l o o p
o f H e n l e , i n w h i c h mo r e
wa t e r i s r e a b s o r b e d . F r o m
h e r e , t h e f i l t r a t e mo v e s
u p wa r d s i n t o t h e d i s t a l
t u b u l e , a n d f i n a l l y t o t h e
c o l l e c t i n g d u c t . Th i s d u c t
c o l l e c t s u r i n e f r o m ma n y
n e p h r o n s .

69. Pl a n t s u s e a v a r i e t y o f
t e c h n i q u e s t o r e mo v e
w a s t e ma t e r i a l s . O x y g e n ,
a b y -p r o d u c t o f
photosynthesis is removed through stomata. The
excess water absorbed from roots is also lost
through stomata via t r a n s p i r a t i o n .
C e l l v a c u o l e s , g u m, r e s i n
e t c . a r e s t o r e d i n o l d
x y l e m t i s s u e s . Wa s t e
p r o d u c t s ma y b e s t o r e d