Digestive System

1. Answer the following questions
based on the video.
1. What is the gateway to the digestive
system?
2. What is the tube that runs from your
mouth to the stomach?
3. What is the first part of the small
intestine where liquified food goes?
4. What is made in the liver and stored in
the gallbladder?
5. What part of the digestive system
absorbs water and salt?

2. The Different
Organs of
Digestion
4th Quarter

3. Digestion
• the process by which food is broken
down into smaller components that
the body can absorb to nourish its
cells.

4. Functions of the Digestive System
• ingestion or taking in food into the
mouth
• digestion and absorption – processing
of food into a form that will be
assimilated into the living cells
• excretion 0r elimination of indigested
substances and certain wastes

5. Phases of Digestion
• Mechanical phase –
chewing or
mastication
• Chemical phase –
enzymes are secreted
together with the
digestive juices

6. Two Main Parts of the Digestive
System
• digestive or alimentary tract –
(mouth, pharynx, esophagus,
stomach, small and large intestines,
rectum and anus)
• accessory organs – (salivary glands,
liver, gallbladder and pancreas)

7. Two Main Parts of the Digestive
System

9. The Mouth
• digestion begins; entrance of food
• teeth, tongue and salivary glands
• Teeth – break down food into small
pieces
• Tongue – muscular organ; mixes food
with the saliva, aids in swallowing
• Salivary glands – secrete saliva that
lubricates food

10. The Mouth
• Saliva – contains enzymes that help in
the chemical digestion of
carbohydrates
• mechanical and chemical digestion of
food
• Bolus – a lubricated, chewed, ball-
shaped mass of food

12. The Pharynx
• throat
• located posterior to the mouth
• common passage way for digestion
and respiration
• breathing and swallowing do not
happen at the same time

13. The Pharynx
• cardiac sphincter – a circular
muscle valve at the upper end of
the stomach, relaxes to allow the
food into the stomach
• epiglottis – prevents the bolus
from entering the trachea

15. The Esophagus
• muscular tube through which food
passes from pharynx to the
stomach
• Peristalsis – a series of rhythmic
wavelike contractions of the
muscles of the esophagus to push
down food into the stomach

16. The Esophagus

18. The Stomach
• expanded organ located between the
esophagus and small intestine
• muscular, elastic , pear-shaped organ
• storing of the swallowed food
• mixing food with the digestive juice it
produces
• conveying its contents slowly into the
small intestine

19. The Stomach
• Pyloric sphincter – circular valve
muscle at the lower end of the
stomach that remains closed when
food enters the stomach
• Chyme – semifluid partially
digested food

21. The Small Intestine
• Three parts: duodenum, jejunum and
ileum
• organ of complete digestion
• secretes enzymes that change food
materials into their simplest components
• longest organ of the digestive system
• Intestinal Villi – very tiny projection that
increase the absorbing capacity of the
small intestine

23. The Large Intestine
• colon
• the next organ after the small intestine
• the larger organ because of its diameter
• temporary stores fecal materials
• absorbs vitamins produced by certain
symbiotic bacteria in the colon
• reabsorbs water from the undigested
residue

24. The Large Intestine
• has three distinct part: ascending colon,
transverse colon and descending colon
• cecum – the proximal part of the
ascending colon; a blind sac that bears
the vermiform appendix
• Sigmoid colon – named because it is
somewhat S-shaped

25. The Large Intestine
• rectum – the last part of the large
intestine
• anus – lower opening that functions as
exit point for fecal material
• defecation or bowel movement – the
process of propelling the feces out of the
body through the anus controlled by a
sphincter in the brain

27. The Accessory Organs
Salivary Glands
• located in the mouth
• Three types: parotid, sublingual and
submandibular

28. The Accessory Organs
Salivary Glands
• saliva – secreted by the salivary gland; a
chemical substance that is a combination
of watery fluid and mucus
• mucus part lubricates the mouth that
aids in swallowing
• serous part contains salivary amylase
ptyalin that digests carbohydrates in the
mouth

29. The Accessory Organs
Liver and Gallbladder
• liver – largest organ in the body
• produces bile from bilirubin, a waste
product formed when red blood cells are
being destroyed

30. The Accessory Organs
Liver and Gallbladder
• Two important functions: emulsification
of fats and neutralization of the partly
digested food from the stomach
• gallbladder – stores the bile
• 500 – 1,000 ml 0f bile is stored and
concentrated in the liver daily

31. The Accessory Organs
Pancreas
• large, elongated gland
that lies posterior to
the stomach
• a yellowish organ that
functions as exocrine
and endocrine gland

32. The Accessory Organs
Pancreas
• Islets of Langerhans – the endocrine part;
secrete hormones important in the
metabolism of sugar
• Pancreatic acini – the exocrine part;
secrete the digestive enzymes directly
into the duodenum
• amylopsin, trypsin, steapsin and nuclease
– secreted by the acinar cells

33. Synthesis:
• Trace what will happen to the food
you ate at breakfast as it enters
your mouth up to the time it
reaches your small intestine.

34. Identify the
parts of the
digestive
system.

35. Assignment:
• Study for a quiz on Thursday,
February 4
Topic: Digestive System