Download 15.2 General Characteristics of the Alimentary Canal

Name:_________________________
Digestive System
15.1 Introduction
Function: the mechanical and chemical breakdown of foods and the absorption of
nutrients by cells
Consists of: alimentary canal ( 9 m from mouth to anus) and accessory organs
15.2 General Characteristics of the Alimentary Canal
(mouth, pharynx, esophagus, stomach, sm intestine, large intestine, anal canal)
Structure of the Wall of the Alimentary Canal
1. Mucosa (mucous membrane) – protects tissues, carries out absorption
2. Submucosa - contains glands, blood vessels, lymphatic vessels, nerves
3. Muscular layer – smooth muscle tissue, circular and longitudinal fibers, pushes food
4. Serosa (serous layer) – visceral peritoneum, outer covering of the tube, moistens and
lubricates structures
Movements of the Tube
Mixing Movements – rhythmic contractions that mix food with digestive juices
Propelling Movements – rings of muscles contract and relax to push food down the
canal (PERISTALSIS)
15.3 Mouth
Mouth – begins digestion by reducing size of
particles (chewing) and mixing with saliva
Tongue – moves food during chewing, connects
to the floor of the mouth via the frenulum,
contains papillae (taste buds)
Palate – forms roof of oral cavity (hard and soft),
uvula at back of the mouth
Palatine tonsils – back of the mouth/throat,
organs that protect against infection
Teeth – primary vs. secondary teeth;
incisors, cuspids, bicuspids (premolars), molars
Anatomy of a Tooth
Crown – projects above the gums
Root – anchored to the alveolar process of the jaw
Name:_________________________
Enamel – made of calcium salts, hardest substance in body (outer surface)
Dentin – similar to bone, surrounds tooth’s central cavity
Blood vessels and nerves extend through the tooth via the root canal
15.4 Salivary Glands
Serous cells produce amylase – splits starch and
glycogen into disaccharides
Mucous cells produce mucus – lubrication during
swallowing
1. Parotid Glands
2. Submandibular Glands
3. Sublingual Glands
15.5 Pharynx and Esophagus
Pharynx – nasal and oral cavitys - nasopharynx, oropharynx, laryngopharynx
Esophagus – moves to the stomach, penetrates the diaphragm at the esophageal
hiatus
lower esophageal sphincter (cardiac sphincter) - prevent food and chemicals from
moving up out of stomach
15.6 Stomach
*J-shaped, puchlike organs
that hangs inferior to the
diaphragm, 1 liter capacity
3 sets of stomach muscles:
longitudinal, oblique,
circular
Greater and Lesser
Curvature
Four main parts of the
stomach
1. Cardiac (esophageal
opening, cardiac sphincter)
2. Fundic (temporary
storage area, lies slightly above the cardiac region)
3. Body (central area of the stomach)
5. Pyloric (pyloric sphincter, controls emptying of the stomach into the sm. Intestine)
Name:_________________________
Lining of the stomach is a mucous membrane – with small openings called gastric pits,
containing gastric glands
Gastric Juice - pepsin / intrinsic factor
Chyme – paste of food molecules after its been broken down by the movement of
stomach and gastric juices, it is released from the pyloric sphincter valve into the first
portion of the small intestine – duodenum
Rugae – folds within the stomach, increase surface area
15.7 Pancreas
has endocrine and exocrine functions - secretes pancreatic juice
Pancreatic juice – digests fats, breaks down nucleic acids into nucleotides
15.8 Liver
BILIARY SYSTEM –
functions to create
bile used in
digestion; liver, gall
bladder and ducts
LIVER- has large
right lobe and small
left lobe
Hepatic portal vein –
delivers blood to the
liver
Functions: maintains
normal concentration of blood glucose, breakdown of lipids and fats, protein metabolism
(forming urea, synthesizing plasma proteins such as clotting factors, converting amino
acids); stores iron and vitamins, destroys damaged red blood cells, removes toxic
substances from the blood, secretes bile
Bile – yellowish-green liquid secreted from hepatic cells (when bile pigments build up in
blood, skin turns green, a condition called jaundice). The hepatic duct joins the cystic
duct to form the common bile duct, which empties into the duodenum
Bile aids in digestion, bile salts break down fat globules into smaller droplets –
emulsification
15.9 Small Intestine
Name:_________________________
*tubular organ that extends from the pyloric sphincter, many loops and coils, fills much
of the abdominal cavity
*receives secretions from the pancreas and liver, completes digestion of nutrients and
chime, absorbs
1. Duodenum - first part of the small intestine
2. Jejunum – second part, ~2.2 m
3. Ilium – third part, longest ~3.3 m *jejunum and ileum are continuous
Mesentery – supports the coils of the small intestine, contains blood vessels to carry
nutrients away
Greater Omentum – peritoneum membrane that drapes like an apron over parts of the
system
Intestinal Villi – increase surface area for absorption
*the main function of the small intestine is to secrete chemicals to break down food and
carry away these nutrients in the blood (absorption)
15.10 Large Intestine
(named because its diameter is
greater than the small
intestine)
1. Cecum – beginning of the
large intestine, pouchlike,
closed end called the
vermiform appendix (ileocecal
valve)
2. Colon – ascending /
transverse / descending /
sigmoid
3. Rectum – stores waste before it is expelled from the body
4. Anus -muscular sphincter which controls the exit of waste
Functions – secretes mucus to protect the wall against abrasion; re-absorbs water and
passes along material that was not digested; contains intestinal flora (bacteria to break
down cellulose, also produce intestinal gas)
Mass movements – large portions of the colon contract to move material through it, 2-3
times a day usually after eating
15.11 Nutrition and Nutrients
Carbohydrates, lipids, proteins, vitamins, minerals / Food Pyramid
Name:_________________________
Disorders of the Digestive System
1. GERD (gastroesophageal reflux disease) / Heartburn
2. Diarrhea or Dysentery
3. Hepatitis (A, B, C)
4. Crohn’s Disease
5. Irritable Bowel Syndrome
6. Stomach Ulcers
7. Lactose Intolerance
8. Appendicitis
9. Hernia
10. Gallstones
11. Celiac Disease
12. Obesity / Gastric Bypass
Name:_________________________
Label the Digestive System
Name:_________________________
Digestive System Concept Map
Name:_________________________
Digestive System Study Guide
1. What is peristalsis? ___________________________________
2. What are papillae and where are they located?
_________________________________________
3. What is the roof of the oral cavity called (2 parts):
____________________________________________
Whereis the uvula? ________________________________________
4. What are the three salivary glands and where are they located?
_________________________________________
5. What are the two types of movements within the alimentary canal?
_______________________________________
6. What are the three main functions of the digestive system?
1) __________________and ___________________
break down of food
2) _____________________________ of nutrients
3) ______________________________ of wastes
7. What is the name of the opening where the esophagus pass through the diaphragm?
_________________________
8. What layer of the alimentary canal carries out absorption?
________________________
What layer contains glands, blood vessels, and nerves?
_______________________________
What layer contains the muscles? ______________________________
What layer covers the structures? _________________________________
9. What valve opens from the esophagus to the stomach?
_______________________________________
What valve opens from the stomach to the small intestine?
___________________________________
10. What structure connects the tongue to the floor of the mouth?
________________________________
11. What digestive enzyme is produced by the salivary glands?
__________________________
12. The part of the stomach that sits slightly above the esophagus is called the
_____________________________
13. What is the hardest substance found in the body?
____________________________
14. The central cavity of the tooth is made of _________________________________
The top of the tooth is called the _______________________________
The part of the tooth that extends below the gums is called the
________________________
15. The front teeth are called _______________________. The back teeth are called
_____________________
The pointed teeth after the incisors are the __________________________
Name:_________________________
16. What is food called after it has been broken down into a paste?
_________________________________
What are the folds inside the stomach called? _________________________________
17. What causes jaundice in newborns? _____________________________________
18. Trace the path of food once it enters the colon (follow through the parts)
________________________ to _____________________________ to
__________________________
19. What is the function of the pancreas?
________________________________________________________
20. What does the bile duct connect? ____________________________ to the
_______________________________
21. Where is the hepatic portal vein located?
_____________________________________________
22. Trace the path of food from the stomach and through all of the parts of the small
intestine:
stomach : ___________________________ >> _______________________ >>
________________________
* Which section is the longest? __________________________________________
23. What is the function of the gall bladder?
__________________________________________
What is the function of bile? ___________________________________
24. What membrane holds the coils of the small intestine together?
_____________________________________
What membrane covers the organs of the digestive system like a curtain ?
_____________________________
25. What is the function of the intestinal villi?
____________________________________________
26. What part of the colon is located right before the rectum?
__________________________________
27. Where is the cecum located?
_________________________________________________________
What “useless” structure is attached to it?
_____________________________________
28. What part of the system stores waste prior to its elimination?
_____________________________
29. What is a mass movement? ______________________________________
30. The “flora” of the large intestine is what?
__________________________________________________
31. What is the function of the large intestine?
________________________________________________
if this function does not work, what sickness can result?
_______________________________________
32. If part of the small intestine pokes through the abdominal muscles, a person has a
________________________
33. Hepatitis (A,B, or C) affects which organ of the digestive system?
______________________________
Name:_________________________
34. The majority of a human’s diet should consist of what?
__________________________________
35. What substance is mainly responsible for breaking down fats?
_______________________________________
What substance is created in the stomach and breaks down food?
__________________________________
36. What is lactose intolerance?
______________________________________________
37. What is another name for gastroesophageal reflux disease?
__________________________________
38. The __________________________________ system refers to the liver, pancreas
and gall bladder.
What are the three ducts found in that system?
__________________________________________
39. If a person has dysentery , they have a dangerous form of
_______________________________
40. Be able to label structures of the digestive system on an image. (This includes a
close-up view of the stomach and biliary system)