Download 15.2 General Characteristics of the Alimentary Canal

Digestive System
15.1 Introduction
Function:
Consists of: alimentary canal and accessory organs
15.2 General Characteristics of the Alimentary Canal
Structure of the Wall of the Alimentary Canal
1. Mucosa (mucous membrane) – protects tissues, carries out
______________________
*Villi increase _______________________
2. Submucosa - glands, vessels, nerves
3. Muscular layer – smooth muscle tissue, _______________
4. Serosa (serous layer) – visceral peritoneum, outer covering, lubricates
structures
Movements of the Tube
_____________________ Movements – rhythmic contractions that mix food
with digestive juices
_____________________ Movements – 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 __________________________, contains papillae (taste buds)
Palate – forms roof of oral cavity (hard and soft); ________________ at back
of the mouth
Palatine tonsils – back of the mouth/throat, organs that protect against
infection. What is tonsillitis?
Teeth – primary vs. secondary teeth;
Label: incisors, cuspids, bicuspids (premolars), molars
Anatomy of a Tooth
Crown – projects above the gums
Root – anchored to the alveolar process of the jaw
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
Describe a root canal.
What are wisdom teeth? Why do they often need to be removed?
15.4 Salivary Glands
Serous cells produce ____________________ – splits starch and glycogen
into disaccharides
Mucous cells produce mucus for lubrication during
___________________________
15.5 Pharynx and Esophagus
Pharynx – nasal and oral cavities - nasopharynx, oropharynx,
______________________________
Esophagus – moves to the stomach, penetrates the diaphragm at the
esophageal _________________
Esophageal sphincter (____________________ sphincter) - prevent food and
chemicals from moving up out of stomach
15.6 Stomach
Four regions of the stomach
1. ____________________(esophageal opening, cardiac sphincter)
2. Fundic (temporary storage area, lies slightly above the cardiac region)
3. Body (central area of the stomach)
5. ___________________(pyloric sphincter, controls emptying of the stomach
into the sm. intestine)
Stomach Lining: _______________ prevents stomach from digesting itself
Glands secrete gastric juices for breakdown of food (pepsin)
___________________ – paste of food molecules after its been broken down
; it is released from the pyloric sphincter valve into the first portion of the small
intestine – duodenum
____________________ – folds within the stomach, increase surface area
15.7 Pancreas
Secretes insulin - breakdown of _______________________ | Pancreatic
juice – digests ____________________
Both empty into the _______________________________
15.8 Liver - has large right and small left lobe
BILIARY SYSTEM – functions to create_____________ used in digestion;
liver, gall bladder and ducts
The cystic duct comes from the ________________ | hepatic duct comes
from the ____________________
Both ducts join to form the ________________________ which empties into
the __________________
Liver Functions: maintains blood glucose, breakdown of lipids and fats,
protein metabolism, stores iron and vitamins, destroys damaged red blood
cells, removes toxic substances, secretes bile
Bile – yellowish-green liquid aids in digestion, break down of fat
What is jaundice?
15.9 Small Intestine
*Main function is the ________________ of nutrients.
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
_____________________ – supports the coils of the small intestine, contains
blood vessels to carry nutrients away
Greater __________________ – (peritoneum) curtain-like membrane that
drapes like an apron over parts of the system
Intestinal Villi – increase
surface area for absorption
15.10 Large Intestine
1. ________________ –
start of the large intestine,
attached appendix
2. Colon – ascending /
transverse / descending /
sigmoid
3. ________________–
stores waste before it is
expelled from the body
4. Anus -muscular sphincter
which controls the exit of waste
Functions –re-absorbs water and passes along material that was not
digested; contains intestinal flora (bacteria to break down cellulose)
What is its main job? ________________________________
Mass movements – large portions of the colon contract to move material
through it, usually after eating (defecation)
What is the Bristol Stool Chart?
Disorders of the Digestive System
1. GERD (gastroesophageal reflux disease) / Heartburn
2. Diarrhea or Dysentery ( c. diff)
3. Hepatitis (A, B, C)
4. Crohn’s Disease / Irritable Bowel Syndrome
5. Stomach Ulcers
6. Lactose Intolerance
7. Appendicitis
8. Hernia
9. Gallstones
10. Celiac Disease
11. Obesity / Gastric Bypass
12. Colon Cancer / Colonoscopy