Page 37 - E-Modul Konsep Tekanan Zat Pada Makhluk Hidup_Neat

Pertukaran Karbondioksida

P r o s e s r e s p i r a s i s e l d i j a r i n g a n t u b u h a k a n m e n g h a s i l k a n k a r b o n d i o k s i d a , h a l i n i
m e n y e b a b k a n t e k a n a n p a r s i a l k a r b o n d i o k s i d a ( P C O₂ ) d a l a m s e l t u b u h l e b i h
t i n g g i d i b a n d i n g d i k a p i l e r v e n a , s e h i n g g a C O₂ b e d i f u s i k e v e n a d a n d i b a w a k e
p a r u - p a r u .

P r o s e s n y a s e b a g a i b e r i k u t :
1 . P . C O₂ d i j a r i n g a n t u b u h = 6 0 m m H g , P . C O₂ d i v e n a = 4 7 m m H g , P . C O₂ d i
a l v e o l u s = 3 5 m m H g ) a t a u l u a r t u b u h = 0 . 3 m m H g ,
2 . K a r e n a p e r b e d a a n t e k a n a n p a r s i a l t e r s e b u t , a k h i r n y a C O₂ a k a n d i k e l u a r k a n
d a r i t u b u h m e l a l u i e k s p i r a s i .
P e n g a n g k u t a n C O₂ o l e h d a r a h d i l a k u k a n 3 c a r a y a i t u :
1 . O l e h p l a s m a d a r a h C O₂ + H₂ O - - > H₂ C O₃ . P e n g a n g k u t a n i n i d i b a n t u e n z i m
k a r b o n a t a n h y d r a s e . j u m l a h C O₂ y a n g d a p a t d i a n g k u t s e b a n y a k 5 % .
2 . O l e h H e m o g l o b i n C O₂ + H b - - > H b C O₂
3 . P e r t u k a r a n k l o r i d a : C O₂ + H₂ O - - > H C O₃
H₂ C O₃ - - > H + d a n H C O₃

H + d i i k a t H b , k a r e n a b e r s i f a t r a c u n d a l a m s e l .
H C O₃ - - > k e p l a s m a d a r a h
H C O₃ d i g a n t i o l e h C l -
P r o s e s p e r t u k a r a n g a s d i d a l a m a l v e e o l u s d a p a t d i l i h a t p a d a g a m b a r 3 . 4 .

Gambar 3.4 Proses Pertukaran Gas di dalam Alveolus

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