The document summarizes the key organs and processes of the digestive system. It describes the roles of the mouth, esophagus, stomach, small intestine, large intestine and associated organs like the liver, gallbladder and pancreas. The key processes discussed are ingestion, propulsion, digestion, absorption and elimination. Mechanical and chemical digestion are explained along with the enzymes involved at each stage and how nutrients are absorbed and waste eliminated.

2. • Identify the main organs of the digestive system
• Describe the structure and function of each organ in the digestion process
• Explain the mechanical and chemical involvement in digestion
• Explain how nutrients are absorbed and waste is eliminated within the digestive
system.
• Identify the importance of other body systems in digestion.

3. Fill in the crossword puzzle

4. The Alimentary canal:
• Mouth
• Pharynx
• Oesophagus
• Stomach
• Small intestine
• Large intestine Rectum and anal canal
The Accessory Organs;
• Three pairs of salivary glands
• The pancreas
• The liver and biliary tract

5. • Ingestion – Taking in food through the mouth
• Propulsion – Mixes and moves along the alimentary tract
• Digestion – Mechanical breakdown in the stomach, chemical digestion of
food into small molecules by enzymes
• Absorption – Digested food substances pass through the wall of some
organs into blood and lymph capillaries for circulation and use by body
cells
• Elimination – Food eaten but can’t be digested and absorbed is
eliminated

6. https://youtu.be/_QYwscALNng

8. AKA the Gastrointestinal Tract and
Digestive Tract
The walls are made up of 4 layers:
• Adventitia or Serosa – Outer covering
• Muscle layer
• Submucosa
• Mucosa – lining
https://youtu.be/R-OhCLIkP5U

9. Specialised cells or glands
release secretions
Saliva – From the Salivary glands
Gastric Juice – From the Gastric Glands
Intestinal Juice – From the Intestinal Glands
Pancreatic Juice – From the Pancreas
Bile – From the Liver
They all contain enzymes that chemically
break down food
Nerve Supply
• The vagus nerve and sacral nerve –
These are both Parasympathetic
which increases muscle activity and
secretions.
• Sympathetic nervous supply – From
the spinal cord, thorax, stomach and
pelvic area. These decrease muscle
activity and decrease secretions

12. • The mouth, also known as the oral cavity, is where food enters
the body and begins its journey through the digestive system.
• The teeth cut and grind food into smaller pieces.
• The salivary glands produce saliva which helps to moisten food
and begin the digestion of carbohydrates.
• The tongue helps to push food pieces into the pharynx.

13. Mechanical Digestion
• Teeth and tongue break food down into
smaller pieces
Chemical Digestion
• Salivary glands produce saliva
• Amylase (enzyme) in saliva begin to
break food down
• Amylase converts starch into glucose.
Your body
produces 1.5L
of saliva each
day!

14. • The oesophagus is a muscular tube connecting the pharynx to the stomach.
• Wave-like peristalsis movements force the food into the stomach.
• At the lower end of the oesophagus is a muscular ring called the oesophageal sphincter which
closes off the end of the oesophagus.
• This traps food in the stomach and stops it re-entering the oesophagus.

15. • The pharynx, or throat, plays a dual role.
• It is a common passageway for air entering the respiratory
system and for food and fluids entering the digestive
system.
• The pharynx contains a flap of tissue known as the
epiglottis that acts as a switch to direct food to the
oesophagus and air to the larynx.

16. • The stomach is divided into four regions: the cardia,
fundus, body, and pylorus.
• It is three muscle layers:
• The longitudinal and circular layers are found throughout
the alimentary canal and move food along using peristaltic
contractions.
• The third, oblique layer in the stomach churns food to
break it down.

17. • The small intestine has three regions: the
duodenum, the jejunum, and the ileum.
• The duodenum is the uppermost part of the small
intestine and only 25-35 cm long.
• During digestion it receives chyme from the
stomach and bile, enzymes, and other digestive
fluids from the liver and the pancreas.

18. • The jejunum is the middle portion of the small intestine (about 2.5
m long and 4 cm wide).
• The ileum is the lower segment and the longest of the three
(about 3.5 m long).
• Finger-like projections called villi line the interior wall throughout
the small intestine.
• The villi absorb most of the nutrients broken down by the
digestive fluids.

19. • Ducts from the pancreas, gallbladder and liver empty
pancreatic juice, bile, and other digestive fluids into the
duodenum.
• The duodenum is the uppermost part of the small intestine, so
it receives chyme from the stomach.
• The duodenum is where most chemical digestion occurs and
where the absorption of vital nutrients, vitamins, & minerals
begins.

20. • Has three sections, it starts with the duodenum, which
has a role in neutralising the low pH of the stomach.
• It then continues into the jejunum, which is where a lot
of absorption of nutrients occurs.
• The final section is the ileum, which connects on to the
large intestine, some fluids are absorbed here.

21. • The regions of the large intestine are the appendix,
cecum, ascending colon, transverse colon,
descending colon, sigmoid colon, rectum, and anal
canal.
• The large intestine absorbs water, electrolytes, and
vitamins that remain after chyme is passed from the
small intestine. It compacts and temporarily stores
faeces for defecation.

22. • The main function of the liver in digestion is the production of bile and its secretion into the
small intestine.
• Bile, a mixture of water, bile salts, cholesterol, and the pigment bilirubin, travels through the
bile ducts and is released into the duodenum where it emulsifies large masses of fat.
• This involves turning these large masses of fat into smaller pieces that are easier for the body
to digest.

23. • The gallbladder is used to store and
recycle excess bile from the small
intestine so that it can be reused for
the digestion of subsequent meals.

24. • The pancreas secretes digestive juices into the small
intestine to complete the chemical digestion of foods.
• This fluid contains enzymes that break down fats,
proteins and carbohydrates.
• It also contains sodium bicarbonate which neutralises
acid in the stomach.

26. Enjoy your Lunch!! 🤣😜💩