Think about… 6.1 The process of human nutrition 6.2 The human digestive system 6.3 Ingestion of food 6.4 Movement of food along the alimentary canal 6.5.

Think about… 6.1 The process of human nutrition 6.2 The human digestive system 6.3 Ingestion of food 6.4 Movement of food along the alimentary canal 6.5 Digestion of food 6.6 Absorption of digested food 6.7 Assimilation of absorbed food 6.8 Egestion Recall ‘Think about…’ Summary concept map

Weight loss surgery Weight loss surgery can help obese people lose weight

 Weight loss surgery stomach ileum duodenum
small bag created at the top of stomach  ileum it connects directly to ileum food bypasses larger stomach and duodenum duodenum

1 What is the role of the stomach

2 How does the surgery help people lose weight

3 What will happen if the food does not pass through the ileum also

6.1 The processes of human nutrition
food 1 ingestion (攝食) complex and insoluble food molecules 2 digestion (消化) simple and soluble food molecules

6.1 The processes of human nutrition
1 ingestion (攝食) 2 digestion (消化) digested food 3 absorption (吸收) 4 assimilation (同化) 5 egestion (排遺) faeces

 The five main processes of nutrition in humans are ingestion
6.1 The processes of human nutrition The five main processes of nutrition in humans are ingestion digestion , , absorption  assimilation and egestion

What does our digestive system
6.2 The human digestive system What does our digestive system (消化系統) consist of?

Alimentary canal (消化道)
6.2 The human digestive system Digestive system Alimentary canal (消化道) Glands (腺)

Alimentary canal 1 mouth cavity 2 pharynx (咽) 3 oesophagus (食道)
6.2 The human digestive system Alimentary canal 1 mouth cavity 2 pharynx (咽) 3 oesophagus (食道) 4 stomach

Alimentary canal duodenum 5 small intestine ileum colon
6.2 The human digestive system Alimentary canal 5 small intestine duodenum ileum 6 large intestine colon rectum 7 anus (肛門)

Glands salivary glands pancreas (胰) liver 6.2
The human digestive system Glands salivary glands pancreas (胰) liver

1 Our digestive system consists of the and alimentary canal
6.2 The human digestive system 1 Our digestive system consists of the and alimentary canal its associated glands

2 Alimentary canal: mouth cavity pharynx oesophagus stomach
6.2 The human digestive system 2 Alimentary canal: mouth cavity start pharynx oesophagus stomach small intestine large intestine end anus

3 Associated glands: salivary glands pancreas , , liver 6.2
The human digestive system 3 Associated glands: salivary glands pancreas , , liver

food is taken in through the mouth
6.3 Ingestion of food mouth cavity food is taken in through the mouth

mastication (咀嚼): chewing food into small pieces
6.3 Ingestion of food teeth mastication (咀嚼): chewing food into small pieces

A) Types of teeth 1 Incisors (門齒) for biting and cutting food
6.3 Ingestion of food A) Types of teeth 1 Incisors (門齒) for biting and cutting food chisel-shaped (鑿形的) flat sharp edges one root

A) Types of teeth 2 Canine (犬齒) well-developed in carnivores
6.3 Ingestion of food A) Types of teeth 2 Canine (犬齒) well-developed in carnivores for tearing flesh pointed and curved one root

A) Types of teeth 3 Premolar (前臼齒) for cutting and grinding food
6.3 Ingestion of food A) Types of teeth 3 Premolar (前臼齒) for cutting and grinding food broad top with cusps 1 or 2 roots

A) Types of teeth 4 Molar (臼齒) similar to premolar but larger
6.3 Ingestion of food A) Types of teeth 4 Molar (臼齒) similar to premolar but larger 2 or 3 roots

B) Structure of a tooth divided into crown (齒冠) neck (齒頸) root (齒根)
6.3 Ingestion of food B) Structure of a tooth divided into crown (齒冠) neck (齒頸) root (齒根)

1 Enamel (琺瑯質) the outermost, hardest region
6.3 Ingestion of food 1 Enamel (琺瑯質) the outermost, hardest region non-living and is made mainly of calcium salt protects teeth from wearing off

1 Enamel (琺瑯質) Around the roots… replaced by cement (牙骨質)
6.3 Ingestion of food 1 Enamel (琺瑯質) Around the roots… replaced by cement 　(牙骨質) cement fibres from cement form periodontal membrane (牙周膜) periodontal membrane

2 Dentine (牙本質) the middle region of the tooth
6.3 Ingestion of food 2 Dentine (牙本質) the middle region of the tooth contains strands of living cytoplasm

3 Pulp cavity (髓腔) living cells nerve fibres blood vessels 6.3
Ingestion of food 3 Pulp cavity (髓腔) living cells nerve fibres blood vessels

3 Pulp cavity (髓腔) nerve fibres detect temperature and pressure
6.3 Ingestion of food 3 Pulp cavity (髓腔) nerve fibres detect temperature and pressure blood vessels supply oxygen and nutrient remove waste

6.3 Ingestion of food C) Dentition of humans dentition (齒系): number and arrangement of different types of teeth represented by a dental formula (齒式)

C) Dentition of humans on each side of the upper jaw: 2 incisors
6.3 Ingestion of food C) Dentition of humans on each side of the upper jaw: 2 incisors 1 canine 2 premolars 3 molars

C) Dentition of humans on each side of the lower jaw: 2 incisors
6.3 Ingestion of food C) Dentition of humans on each side of the lower jaw: 2 incisors 1 canine 2 premolars 3 molars

C) Dentition of humans dental formula of an adult: 2 1 2 3
6.3 Ingestion of food C) Dentition of humans dental formula of an adult: 2 1 2 3 i , c , pm , m 2123

D) Milk teeth and permanent teeth
6.3 Ingestion of food D) Milk teeth and permanent teeth first set of teeth: milk teeth (乳齒) appear during the first two years 2102 dental formula:

6.3 Ingestion of food D) Milk teeth and permanent teeth second set of teeth: permanent teeth (恆齒) replace milk teeth between the ages of 6 and 12 will not be replaced when lost

6.3 Ingestion of food D) Milk teeth and permanent teeth permanent teeth milk teeth

1 Food is put into the mouth cavity
6.3 Ingestion of food 1 Food is put into the mouth cavity and cut up by The process of chewing food into small pieces is called teeth mastication .

2 Match the functions of different types of teeth:
6.3 Ingestion of food 2 Match the functions of different types of teeth: incisors   tearing flesh canine   biting and cutting premolars   crushing and grinding molars 

3a Label the structure of the tooth.
6.3 Ingestion of food 3a Label the structure of the tooth. crown neck root

3b Label the structure of the tooth.
6.3 Ingestion of food 3b Label the structure of the tooth. enamel dentine pulp cavity

6.3 Ingestion of food 4a refers to the number and arrangement of different types of teeth in a mammal. Dentition It can be represented by a . dental formula

4b Humans have two sets of teeth
6.3 Ingestion of food 4b Humans have two sets of teeth in a lifetime: i) ii) milk teeth permanent teeth

What will happen to us after mastication?
6.4 Movement of food along the alimentary canal What will happen to us after mastication?

The tongue shapes the food into a bolus
6.4 Movement of food along the alimentary canal Animation 1 Swallowing bolus (食團) before swallowing: Food is chewed teeth tongue The tongue shapes the food into a bolus

1 Swallowing during swallowing:
6.4 Movement of food along the alimentary canal 1 Swallowing during swallowing: 1 The tongue pushes the bolus towards pharynx

6.4 Movement of food along the alimentary canal 1 Swallowing during swallowing: 2 The soft palate (軟腭) moves up to prevent the bolus from entering the nasal cavity

6.4 Movement of food along the alimentary canal 1 Swallowing during swallowing: 3 The epiglottis (會厭) covers the trachea 4 The bolus enters the oesophagus

2 Peristalsis (蠕動) rhythmic contraction and relaxation of the muscles
6.4 Movement of food along the alimentary canal 2 Peristalsis (蠕動) rhythmic contraction and relaxation of the muscles circular muscle (環肌) longitudinal muscle (縱肌) lumen (管腔) alimentary canal

6.4 Movement of food along the alimentary canal 2 Peristalsis (蠕動) circular muscles contract, longitudinal muscles relax circular muscles relax, longitudinal muscles contract food food moved forward

1 Food is moved from the mouth cavity down the oesophagus by
6.4 Movement of food along the alimentary canal 1 Food is moved from the mouth cavity down the oesophagus by swallowing and down from the oesophagus towards the anus by peristalsis

contraction and relaxation
6.4 Movement of food along the alimentary canal 2 Peristalsis is the rhythmic contraction and relaxation circular longitudinal of the and muscles in the wall of alimentary canal. It causes the food to move forward along the canal.

 undigested food is too large to pass through the wall
6.5 Digestion of food undigested food is too large to pass through the wall wall of alimentary canal (differentially permeable)  blood alimentary canal undigested food molecules

digested food molecules
6.5 Digestion of food digestion makes the food smaller, simpler and soluble for absorption blood alimentary canal digested food molecules

Physical digestion (機械消化)
6.5 Digestion of food Physical digestion (機械消化) breaks down food into smaller pieces increases surface area for action of digestive juices (消化酶) physical action food smaller surface area larger surface area

6.5 Digestion of food Physical digestion (機械消化) examples: 1 Chewing by teeth 2 Churning (劇烈攪動) in the stomach

6.5 Digestion of food Physical digestion (機械消化) examples: 3 Peristalsis along alimentary canal 4 Emulsification (乳化) by bile salts lipids small droplets

digestive enzymes (消化酶)
6.5 Digestion of food Chemical digestion (化學消化) chemical reactions in which large, complex food molecules are broken down digestive enzymes (消化酶) large, complex small, simple

complex carbohydrates
6.5 Digestion of food three types of digestive enzymes 1 Carbohydrases (碳水化合酶) e.g. amylase, sucrase and maltase complex carbohydrates simpler sugars

three types of digestive enzymes
6.5 Digestion of food three types of digestive enzymes 2 Proteases (蛋白酶) e.g. pepsin, trypsin and peptidases polypeptides protein peptides amino acids

three types of digestive enzymes
6.5 Digestion of food three types of digestive enzymes 3 Lipase (脂肪酶) e.g. pancreatic lipase fat fatty acids glycerol

Digestion in mouth cavity
6.5 Digestion of food Digestion in mouth cavity Animation food is chewed into small pieces and mixed with saliva

6.5 Digestion of food Digestion in mouth cavity Saliva secreted by salivary glands slightly alkaline salivary glands

6.5 Digestion of food Digestion in mouth cavity Saliva consists of i) salivary amylase starch maltose ii) mucus (黏液) - moistens and lubricates (潤滑) food

6.5 Digestion of food Digestion in mouth cavity Saliva consists of iii) water - dissolves soluble substances in food

Digestion in stomach Structure of the stomach oesophagus muscle bag
6.5 Digestion of food Digestion in stomach Structure of the stomach oesophagus muscle bag duodenum

Digestion in stomach Structure of the stomach
6.5 Digestion of food Digestion in stomach Structure of the stomach cardiac sphincter (賁門括約肌) - closes the entrance pyloric sphincter (幽門括約肌) - regulates the release of food into duodenum

Digestion in stomach Structure of the stomach
6.5 Digestion of food Digestion in stomach Structure of the stomach gastric glands inside pits stomach wall (450) gastric glands secrete gastric juice (胃液)

Digestion in stomach Gastric juice contains i) proteases protein
6.5 Digestion of food Digestion in stomach Gastric juice contains i) proteases protein peptides

Digestion in stomach Gastric juice contains ii) hydrochloric acid
6.5 Digestion of food Digestion in stomach Gastric juice HCl contains ii) hydrochloric acid - provides an acidic medium for the action of proteases - kills most bacteria in food bacteria

Digestion in stomach Gastric juice mucus contains iii) mucus
6.5 Digestion of food Digestion in stomach Gastric juice mucus contains iii) mucus - protects stomach from being damaged by proteases and hydrochloric acid proteases & HCl

Digestion in stomach food churning & chemical digestion
6.5 Digestion of food Digestion in stomach food churning & chemical digestion semi-solid paste called chyme (食糜)

Digestion in small intestine
6.5 Digestion of food Digestion in small intestine three digestive juices 1 Bile secreted by liver stored in gall bladder released to duodenum through bile duct (膽管)

6.5 Digestion of food Digestion in small intestine 1 Bile has no enzymes but contains i) bile salts - emulsify lipids into small droplets lipids emulsification larger surface area smaller surface area

6.5 Digestion of food Digestion in small intestine 1 Bile ii) bile pigments - give green colour to bile iii) sodium hydrogencarbonate - neutralizes the acidic chyme - provides an alkaline medium for the actions of enzymes in duodenum

 Digestion in small intestine 1 Bile
6.5 Digestion of food Digestion in small intestine 1 Bile  Bile is produced by the gall bladder.

6.5 Digestion of food Digestion in small intestine 1 Bile Bile is produced by the liver and temporarily stored in the gall bladder.

Investigation of the effect of bile salts on oil
6.5 Digestion of food Animation 6.3 Investigation of the effect of bile salts on oil peanut oil bile salt solution 1 Add 10 drops of bile salt solution to 1 cm3 of peanut oil.

Results and discussion
6.5 Digestion of food 6.3 2 Stopper the test tube and shake for 30 seconds. Observe the mixture and note any changes. shake Results and discussion An emulsion (乳狀物) is formed. This shows that bile salts can break down lipids into tiny droplets.

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice pancreatic duct secreted by pancreas released to duodenum through pancreatic duct slightly alkaline pancreas

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice contains: i) pancreatic amylase starch maltose

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice contains: ii) protease protein peptides

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice contains: ii) protease peptides amino acids

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice contains: iii) lipase lipid fatty acids glycerol

6.5 Digestion of food Digestion in small intestine 2 Pancreatic juice contains: iv) sodium hydrogencarbonate - neutralizes the acidic chyme - provides an alkaline medium for the actions of enzymes in duodenum

6.5 Digestion of food Digestion in small intestine 3 Intestinal juice secreted by the glands on the wall of the small intestine duodenum ileum

6.5 Digestion of food Digestion in small intestine 3 Intestinal juice slightly alkaline duodenum contains mucus no enzymes ileum

6.5 Digestion of food Digestion in small intestine some specialized cells on the wall also involved in digestion duodenum specialized cells ileum

6.5 Digestion of food Digestion in small intestine enzymes present on their cell membrane duodenum enzymes here specialized cells ileum

6.5 Digestion of food Digestion in small intestine The enzymes include: i) carbohydrases disaccharides monosaccharides

6.5 Digestion of food Digestion in small intestine The enzymes include: ii) proteases peptides amino acids

6.5 Digestion of food Digestion in small intestine Digestion completed at the end of ileum monosaccharides ready for absorption amino acids glycerol fatty acids

1 The food we take in is too
6.5 Digestion of food 1 The food we take in is too large to pass through the wall of the alimentary canal, which is differentially permeable. Digestion makes the food , and for absorption. smaller simpler soluble

6.5 Digestion of food 2a Physical digestion is mainly brought about by action of the teeth, in the stomach, along the alimentary canal, and of lipids by bile salts. chewing churning peristalsis emulsification

2b Physical digestion increases the of food for chemical digestion.
6.5 Digestion of food 2b Physical digestion increases the of food for chemical digestion. surface area

6.5 Digestion of food 3a involves chemical reactions in which large, complex food molecules are broken down into smaller, simpler forms. The reactions are catalysed by Chemical digestion digestive enzymes

3b Some digestive enzymes are present in the secreted by the .
6.5 Digestion of food 3b Some digestive enzymes are present in the secreted by the digestive juices digestive glands

4a Digestion of carbohydrates: Mouth cavity Duodenum salivary amylase
6.5 Digestion of food 4a Digestion of carbohydrates: Mouth cavity salivary amylase starch maltose in saliva Duodenum pancreatic amylase starch maltose in pancreatic juice

4a Digestion of carbohydrates: Small intestine disaccharides
6.5 Digestion of food 4a Digestion of carbohydrates: Small intestine disaccharides monosaccharides carbohydrases on the cell membranes of the specialized cells in the intestinal wall

4b Digestion of proteins: Stomach Duodenum proteases protein peptides
6.5 Digestion of food 4b Digestion of proteins: Stomach proteases protein peptides in gastric juice Duodenum protein, proteases peptides, peptides in pancreatic juice amino acids

4b Digestion of proteins: Small intestine proteases amino acids
6.5 Digestion of food 4b Digestion of proteins: Small intestine proteases amino acids peptides on the cell membrane of the specialized cells in the intestinal wall

4c Digestion of lipids: Duodenum bile salt small droplets lipids in
6.5 Digestion of food 4c Digestion of lipids: Duodenum bile salt small droplets lipids in bile lipase fatty acids, lipids in pancreatic juice glycerol

mainly takes place in ileum
6.6 Absorption of digested food mainly takes place in ileum

Adaptation of small intestine for food absorption
6.6 Absorption of digested food Adaptation of small intestine for food absorption 1 Long intestine allows sufficient time for absorption It’s 7m long!

cross-section of small intestine
6.6 Absorption of digested food Adaptation of small intestine for food absorption 2 Highly-folded intestinal wall and numerous villi (絨毛) epithelium covered with villi cross-section of small intestine

Adaptation of small intestine for food absorption
6.6 Absorption of digested food Adaptation of small intestine for food absorption 2 Highly-folded intestinal wall and numerous villi (絨毛) epithelium covered with villi inner surface of ileum

Adaptive features of villi
6.6 Absorption of digested food Adaptive features of villi 1 Finger-like projections increases surface area for absorption

6.6 Absorption of digested food Adaptive features of villi 2 Thin epithelium reduces the distance for diffusion of food molecules

6.6 Absorption of digested food Adaptive features of villi lacteal 3 Presence of lacteal and a network of blood capillaries carry away the absorbed food molecules rapidly blood capillary

6.6 Absorption of digested food Adaptive features of villi 4 Movement of villi caused by peristalsis keeps a steep concentration gradient of food molecules

Absorption of digested food
6.6 Absorption of digested food Absorption of digested food Into the blood Animation diffusion monosaccharides amino acids active transport minerals water-soluble vitamins

6.6 Absorption of digested food Absorption of digested food Into the blood hepatic vein liver hepatic portal vein all parts of the body

6.6 Absorption of digested food Absorption of digested food Into the lymph lumen epithelium lacteal fatty acid fatty acid glycerol glycerol lipid lipid

6.6 Absorption of digested food Absorption of digested food Into the lymph lymph vessel all parts of the body

6.6 Absorption of digested food Absorption of water most water is absorbed in stomach and small intestine osmosis water blood capillary

6.6 Absorption of digested food 6.4 Simulation of digestion and absorption in the small intestine using dialysis tubing 1 Tie a knot at one end of a dialysis tubing. Fill the tubing with equal volumes of starch solution and amylase solution.

2 Tie the other end of the tubing.
6.6 Absorption of digested food 6.4 2 Tie the other end of the tubing. dialysis tubing water at 37oC starch and amylase 3 Immerse the tubing in water at 37°C.

6.6 Absorption of digested food 6.4 4 Test the water outside the tubing immediately for starch and reducing sugars using iodine solution and Benedict’s solution respectively. Perform the same tests after one hour.

6.6 Absorption of digested food 6.4 Results and discussion At the beginning of the experiment, neither starch nor reducing sugars are present in the water. However, reducing sugars are detected after one hour.

6.6 Absorption of digested food 6.4 Results and discussion These results show that amylase helps break down starch into reducing sugars and only the reducing sugar molecules are small enough to pass through the dialysis tubing.

1 Absorption is the movement of food molecules from the
6.6 Absorption of digested food 1 Absorption is the movement of food molecules from the alimentary canal into the circulatory system. It takes place mainly in the ileum.

2a How is the small intestine adapted for food absorption? Adaptation
6.6 Absorption of digested food 2a How is the small intestine adapted for food absorption? Adaptation Significance Increase surface area for absorption Highly-folded wall and numerous villi

Reduces the distance for diffusion of food molecules
6.6 Absorption of digested food 2b How is the small intestine adapted for food absorption? Adaptation Significance Reduces the distance for diffusion of food molecules Thin epithelium

2c How is the small intestine adapted for food absorption? Adaptation
6.6 Absorption of digested food 2c How is the small intestine adapted for food absorption? Adaptation Significance Carry away the absorbed food molecules rapidly Presence of lacteal and a network of blood capillaries

2d How is the small intestine adapted for food absorption? Adaptation
6.6 Absorption of digested food 2d How is the small intestine adapted for food absorption? Adaptation Significance Keeps a steep concentration gradient of food molecules Movement of villi caused by peristalsis

6.6 Absorption of digested food 3a Monosaccharides, amino acids, minerals and water-soluble vitamins are absorbed into the blood capillaries of the villi by diffusion and active transport. They are carried to the liver via the hepatic portal vein

6.6 Absorption of digested food 3b Fatty acids and glycerol diffuse into the epithelium of the villi. Here they recombine to form before entering the lipids lacteals

6.7 Assimilation of absorbed food
the uptake and use of absorbed food molecules for metabolism

The fate of absorbed food
6.7 Assimilation of absorbed food The fate of absorbed food 1 Glucose i) for releasing energy glucose respiration energy

6.7 Assimilation of absorbed food The fate of absorbed food 1 Glucose ii) excess glucose is converted into glycogen or lipid in liver stored in glycogen liver / muscle lipid stored under skin / around internal organs

6.7 Assimilation of absorbed food The fate of absorbed food 2 Amino acids i) for making proteins enzymes proteins for growth antibodies proteins for repair hormones ii) excess amino acids are deaminated in liver

6.7 Assimilation of absorbed food The fate of absorbed food 3 Lipids i) as energy reserve ii) for making cell membrane iii) for protecting internal organs or reducing heat loss subcutaneous fat

The roles of the liver 1 Regulate blood glucose level
6.7 Assimilation of absorbed food The roles of the liver 1 Regulate blood glucose level blood glucose level > normal glucose liver glycogen blood glucose level < normal liver glucose glycogen

6.7 Assimilation of absorbed food The roles of the liver 2 Storage of glycogen, iron and fat-soluble vitamins main site for storing glycogen glycogen

6.7 Assimilation of absorbed food The roles of the liver 2 Storage of glycogen, iron and fat-soluble vitamins stores fat-soluble vitamins vitamin A vitamin D

6.7 Assimilation of absorbed food The roles of the liver 2 Storage of glycogens, iron and fat-soluble vitamins for storing iron from the breakdown of red blood cells iron red blood cells

The roles of the liver 3 Production of bile, vitamin A and heat heat
6.7 Assimilation of absorbed food The roles of the liver 3 Production of bile, vitamin A and heat heat secretes bile changes carotene to vitamin A metabolic activities produces heat

The roles of the liver 4 Deamination urea amino group
6.7 Assimilation of absorbed food The roles of the liver 4 Deamination urea amino group excess amino acids carbohydrates remaining parts lipids

The roles of the liver 5 Detoxification (解毒) toxins harmless
6.7 Assimilation of absorbed food The roles of the liver 5 Detoxification (解毒) toxins (e.g. alcohol, drugs) harmless substances

1 Assimilation is the uptake and
6.7 Assimilation of absorbed food 1 Assimilation is the uptake and use of absorbed food molecules by cells for metabolism.

2 How are the absorbed food molecules assimilated inside cells?
6.7 Assimilation of absorbed food 2 How are the absorbed food molecules assimilated inside cells? glucose for releasing energy amino acids for making proteins for making cell membrane lipids as energy reserve

3 The roles of the liver include:
6.7 Assimilation of absorbed food 3 The roles of the liver include: regulates blood glucose level stores , and glycogen iron fat-soluble vitamins produces , and bile vitamin A heat

3 The roles of the liver include:
6.7 Assimilation of absorbed food 3 The roles of the liver include: deaminates excess amino acids detoxifies mild toxins

secretions from alimentary canal
6.8 Egestion the process of expelling faeces (糞便) from the body also called defaecation (排糞) faeces consist of secretions from alimentary canal dietary fibre bacteria dead cells

faeces stored in rectum temporarily
6.8 Egestion faeces stored in rectum temporarily anal sphincter muscle relaxes and rectum muscle contracts to push the faeces out

is the process of expelling faeces from the body.
6.8 Egestion Egestion is the process of expelling faeces from the body.

1 What is the role of the stomach?
The stomach churns to break down food into smaller pieces physically. It secretes proteases to chemically digest proteins. It also releases hydrochloric acid which kills most bacteria in food.

2 How does the surgery help people lose weight?
Without passing through the stomach and duodenum, the food cannot be fully digested. Therefore, fewer food molecules are absorbed by the body.

3 What will happen if the food does not pass through the ileum also?
It may result in malnutrition as most consumed food is undigested and the body cannot get enough nutrients for healthy growth.

Nutrition ingestion absorption egestion digestion assimilation villi
consists of ingestion absorption egestion digestion assimilation occurs mainly in occurs in villi body cells

digestion physical digestion chemical digestion enzymes
involves physical digestion chemical digestion brought about by enzymes

emulsification of lipids by bile salts
physical digestion brought about by chewing by teeth churning in stomach peristalsis emulsification of lipids by bile salts

Think about… 6.1 The process of human nutrition 6.2 The human digestive system 6.3 Ingestion of food 6.4 Movement of food along the alimentary canal 6.5.

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Think about… 6.1 The process of human nutrition 6.2 The human digestive system 6.3 Ingestion of food 6.4 Movement of food along the alimentary canal 6.5.

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