Page 36 - E-Modul Konsep Tekanan Zat Pada Makhluk Hidup_Neat

Mekanisme Pertukaran Oksigen dan

Karbondioksida

Pertukaran Oksigen

K e b u t u h a n o k s i g e n s e t i a p i n d i v i d u b e r b e d a - b e d a t e r g a n t u n g p a d a u m u r ,
a k t i v i t a s , b e r a t b a d a n , j e n i s k e l a m i n d a n j u m l a h m a k a n a n y a n g d i k o n s u m s i .
D a l a m k e a d a a n b i a s a j u m l a h o k s i g e n y a n g d i b u t u h k a n s e b a n y a k 3 0 0 m l p e r h a r i
p e r i n d i v i d u .
1 . S e k i t a r 9 7 % o k s i g e n y a n g m a s u k k e d a l a m d a r a h a k a n d i a n g k u t o l e h
h e m o g l o b i n / e r i t r o s i t . O k s i g e n y a n g t e r i k a t d a l a m H b d i k e n a l d e n g a n
o k s i h e m o g l o b i n ( H b O₂ ) . d e n g a n r e a k s i s e b a g a i b e r i k u t : H b₄ + 4 O₂ - > 4 H b O₂

2 . 2 - 3 % l a g i a k a n l a r u t d a n d i a n g k u t o l e h p l a s m a d a r a h .
P r o s e s p e n g i k a t a n d a n p e l e p a s a n o k s i g e n d i p e n g a r u h i O l e h t e k a n a n o k s i g e n ,
k a d a r o k s i g e n , d a n k a d a r k a r b o n d i o k s i d a d i j a r i n g a n t u b u h , d a n t e r j a d i s e c a r a
d i f u s i .

P r o s e s d i f u s i b e r l a n g s u n g s e d e r h a n a , y a i t u h a n y a d e n g a n g e r a k a n m o l e k u l
s e c a r a b e b a s , m e l a l u i m e m b r a n s e l d a r i k o n s e n t r a s i t i n g g i a t a u t e k a n a n t i n g g i k e
k o n s e n t r a s i r e n d a h a t a u t e k a n a n r e n d a h .

P r o s e s n y a d i f u s i d a p a t d i j e l a s k a n s e b a g a i b e r i k u t :
1 . T e k a n a n o k s i g e n d i u d a r a ( P O₂ = 1 6 0 m m H g ) , d a l a m a l v e o l u s ( P O₂ = 1 0 5 m m H g ) . d i
a r t e r i 1 0 0 m m H g , d i j a r i n g a n 4 0 m m H g , d i v e n a l e b i h k e c i l 4 0 m m H g .
2 . J a d i k a r n a t e k a n a n p a r s i a l o k s i g e n b e r b e d a , m a k a h e m o g l o b i n a k a n
m e n g a n g k u t o k s i g e n s a m p a i k e j a r i n g a n t u b u h .
3 . D i d a l a m s e l - s e l t u b u h , o k s i g e n d i g u n a k a n u n t u k p r o s e s r e s p i r a s i d i d a l a m
m i t o k o n d r i a s e l .

4 . S e m a k i n b a n y a k o k s i g e n y a n g d i g u n a k a n o l e h s e l - s e l t u b u h , s e m a k i n b a n y a k
k a r b o n d i o k s i d a y a n g t e r b e n t u k d a r i p r o s e s r e s p i r a s i .
5 . S e t i a p 1 0 0 c c d a r a h d i a r t e r i m a m p u m e n g a n g k u t 1 9 c c O₂ .
6 . S e t e l a h s a m p a i d i v e n a s e t i a p 1 0 0 c c d a r a h m a s i h m e n g a n d u n g O₂ s e b a n y a k
1 2 c c . V o l u m e O₂ y a n g t e r t i n g g a l d i j a r i n g a n a d a l a h 7 c c .
7 . J i k a v o l u m e d a r a h a d a 5 l i t e r , a t a u 5 0 0 0 c c , m a k a v o l u m e O₂ y a n g s a m p a i k e
j a r i n g a n s e k a l i b e r e d a r a d a l a h : 5 0 0 0 / 1 0 0 x 7 c c = 5 0 x 7 = 3 5 0 c c

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