Digestive System in a human, Slides of Biology

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q N u t r i e n t s a r e s u b s t a n c e s r e q u i r e d f o r m e t a b o l i s m , g r o w t h , m a i n t e n a n c e , a n d repair. q Heterotrophs are group to: q Herbivores q Carnivores q Omnivores

q N u t r i e n t s a r e s u b s t a n c e s r e q u i r e d f o r m e t a b o l i s m , g r o w t h , m a i n t e n a n c e , a n d repair. q Heterotrophs are group to: q Herbivores q Carnivores q Omnivores

Types of Digestive System

q Incomplete digestive tract q o n l y o n e o p e n i n g : a m o u t h t h a t b o t h i n g e s t s f o o d a n d ejects wastes. q must digest food and eliminate the residue before the next meal can begin. q Complete Digestive tract q Two openings: the mouth is the entrance, and the anus is the exit. q can digest one m ea l a t t h e

Types of Digestive System

Human Digestive System Consist of several organs

q Human digestive system are composed of q Gastrointestinal tract- a long continuous, hollow m u s c u l a r t u b e t h a t extends from mouth to anus q Accessory organs- not part of continuous tube but produce and secretes enzymes in GI tract to aid the digestion of food

Underlying tissue of Digestive system

Food processing begins in the Mouth

q Where the digestion begins.

q T h e m u s c u l a r t o n g u e a r e involved in taste, mastication and swallowing. It also move the food inside and mixes it with saliva. q T h e t e e t h a c c o m p l i s h e d t h e mastication ( breaking down the f o o d i n t o s m a l l e r p i e c e s ) producing bolus. q Saliva are secreted from salivary glands that contain enzymes for breaking complex sugar.

Food processing begins in the Mouth

q Mastication: break up foods into small particles and mix with fluid secretion. q Swallowing are initiated by voluntary action and then continued under involuntary control a f t e r i t p a s s e s t h e pharynx

Stomach stores, digest and churn food

q A saclike portion of digestive tract. Serves as temporary site for food. It can expand and contain 2 to 4L of food when full. q T h e c e l l w a l l h a s g l a n d s

( m u c u s s e c r e t i n g c e l l ,

parietal cell and chief cell)

q I t s e c r e t e s g a s t r i c j u i c e n e c e s s a r y f o r f u r t h e r breakdown of food bolus to

Stomach stores, digest and churn food

q Mucus secreting cell produce a thick substance to protect the stomach from acid. q P a r i e t a l c e l l - p r o d u c e s hydrochloric acid (HCl) q Chief cell- secretes pepsinogen to breakdown protein

Small Intestine: Digest and Absorb nutrients

q A tubular muscle organ that completes digestion and absorption. 3 to 7 meters in length. q Epithelial wall of small intestine is covered with tiny, fingerlike

projection called microvilli

(increase the surface of

absorption). About 300 𝐀

2 q It receives the secreted enzymes

Small Intestine: Digest and Absorb nutrients

q Small intestine are divided into

3 sections ( duodenum,

jejunum and ilium )

q It secretes several enzymes to breakdown carbohydrates, protein, nucleic acid and lipids. q Before chyme leaves small intestines, 90% of nutrients are absorb and pass to the blood stream.