Enzymes and the digestive systemObjective: To understand the structure and function of the major parts of the digestive system.Outcomes: ~ Identify the structures found in the digestive system and describe their function.~ Explain how both physical and chemical processes are involved in digestion. ~ Explain the role of enzymes in the digestive system.

Keywords

EnzymesDigestionAbsorptionEgestionAssimilation CarbohydrasesLipasesProteasesHydrolysis

Thursday 13 April 2023

The Digestive System

Mouth (containing salivary glands)

Liver

Oesophagus (Gullet)

Stomach

Pancreas

Large intestine

Small intestine

Gall bladder

AnusRectum

Organ FunctionChurns up food with hydrochloric acid. Undigested food passes along here and water is reabsorbed. Makes bile which is then stored in the gall bladder. Digested food is absorbed into the blood here.Makes enzymes. Squeezes food towards the stomach.Breaks food into smaller pieces.

The alimentary canal along with a range of organs and glands (produce enzymes) make up the digestive system.

Function? To break down large insoluble molecules of food into smaller soluble ones. ~ Physical digestion~ Chemical digestion (enzymes)

e.g. carbohydrate glucose

PeristalsisInvoluntary waves of muscular contraction

The mouthPhysical digestion of food by the teeth and tongue, forming a bolus.

Salivary glands secrete saliva:~ water-dissolves any soluble substances~ mucus-lubrication~ lysozymes- kill bacteria~ amylase-digests starch into maltose (chemical digestion)

The oesophagusA muscular tube connecting the mouth to the stomach.

Peristalsis

No digestion occurs here.

Mouth

Lungs

Stomach

Oesophagus

Trachea

Thick muscular wall

The stomachPhysical digestion occurs due to muscles in the stomach which churns the food forming chyme. Gastric glands secrete gastric juice:~ Enzymes (proteases) provide chemical digestion. ~ HCl acid (pH1) to kill bacteria.~ Mucus to prevent the stomach from being digested.

The pancreasLarge gland which secretes pancreatic juice.

This contains enzymes including lipase, protease and amylase.

Stomach

Pancreas

Gall bladder

Small intestine

Duct

Duct

The small intestineLong muscular tube (6.5m)

~ Duodenum: Further digestion takes place here due to enzymes secreted by the intestine walls and from pancreatic juice. Bile is also secreted here via the liver, which emulsifies fats and neutralises stomach acid. ~ Jejunum: Digestion and absorption. Surface area is increased due to villi and microvilli. ~ Ileum: Final digestion and absorption.

The large intestineWhere most water is reabsorbed.

Food becomes drier forming faeces.

Stored in the rectum and released via the anus, egestion.

Transverse colon

Ascending colon

Descending colon

Rectum

Appendix

Anus

Chemical digestion

Large molecule?

Small molecule?

Group of enzymes involved?

CarbohydratesProteinsFats

Chemical digestion is...Hydrolysis is...

Copy and complete the table below.

Following digestion small molecules are...

Physical digestion Vs.

List 2 places where this type of digestion occurs.

Describe the importance of this type of digestion.

Organ Function

Churns up food with hydrochloric acid.

Undigested food passes along here and water is reabsorbed.

Makes bile which is then stored in the gall bladder.

Digested food is absorbed into the blood here.

Makes enzymes.

Squeezes food towards the stomach.

Breaks food into smaller pieces.

Organ Function

Churns up food with hydrochloric acid.

Undigested food passes along here and water is reabsorbed.

Makes bile which is then stored in the gall bladder.

Digested food is absorbed into the blood here.

Makes enzymes.

Squeezes food towards the stomach.

Breaks food into smaller pieces.

Digestive System: Recap Digestive System: Recap