Digestive System

Question 1

The Digestive System

Answer 1

• General anatomy and digestive processes
• Mouth through esophagus
• Stomach
• Liver, gallbladder and pancreas
• Small intestine
• Chemical digestion and absorption
• Large intestine

Question 2

Digestive Functions:

Answer 2

• Ingestion - intake of food
• Digestion - breakdown of molecules
• Absorption - uptake nutrients into blood/lymph
• Defecation - elimination of undigested material

Question 3

Stages of Digestion:

Answer 3

• Mechanical digestion
• Chemical digestion

Question 4

Mechanical Digestion

Answer 4

physical breakdown of food into smaller particles (churning - pag nguya) using teeth and tounge

Question 5

Results of Chemical digestion:

Answer 5

• polysaccharides into monosaccharides
• proteins into amino acids
• fats into glycerol and fatty acids

Question 6

Chemical Digestion

Answer 6

series of hydrolysis reactions that break macromolecules into their monomers

• enzymes from saliva, stomach, pancreas and intestines

Question 7

Digestive Processes:

Answer 7

• Motility - muscular contraction that break up food, mix it with enzymes and move it along
• Secretion - digestive enzymes and hormones
• Membrane Transport - absorption of nutrients

Question 8

digestive enzymes and hormones:

Answer 8

• amylase - breaks down starch (mouth)
• pepsin - breaks down proteins available in food (stomach)
• lipase - breaks down fats/lipids (small intestine glands)

Question 9

Digestive tract (GI tract)

Answer 9

30 foot long tube extending from mouth to anus

Question 10

Accessory organs:

Answer 10

teeth, tongue, liver, gallbladder, pancreas, salivary glands

Question 11

Tissue Layers of GI Tract:

Answer 11

• Mucosa: epithelium, lamina propria, muscularis mucosae
• Submucosa: esophageal glands
• Muscularis externa: inner circular layer, outer longitudinal layer
• Adventitia or Serosa: areolar tissue or mesothelium (serosa covers most of the GI organ, acts as protective coat)

Question 12

Inner Circular Layer and Outer Longitudinal Layer

Answer 12

Inner Circular Layer: they constrict the lumen aids in mixing
Outer Longitudinal Layer: helps in the peristalsis

Question 13

Enteric Nervous Control

Answer 13

• Second brain of GI tract
• Able to function independently of central nervous system (CNS)

Question 14

two nerve networks of Enteric Nervous Control:

Answer 14

Submucosal Plexus:
- controls glandular secretion of mucosa
- contractions of muscularis mucosae

Myenteric Plexus:
- controls peristalsis
- contractions of muscularis externa

Question 15

• __________ of small intestines holds many blood vessels
• ________ anchors colon to posterior body wall

Answer 15

Mesentery and Mesocolon

Question 16

connects/attaches stomach to liver

Answer 16

Lesser Omentum

Question 17

covers small intestines like an apron

Answer 17

Greater Omentum

Question 18

short myenteric reflexes (swallowing)

Answer 18

Neural Control

Question 19

messengers diffuse into bloodstream, distant targets

Answer 19

Hormones

Question 20

messengers diffuse to nearby target cells

Answer 20

Paracrine secretions

Question 21

keep food between teeth for chewing; essential for speech and suckling in infants

Answer 21

Cheeks and lips

Question 22

space between teeth and cheeks

Answer 22

vestibule

Question 23

_______ - cutaneous area versus ________ - red area

Answer 23

Lips
Vermilion

Question 24

• a muscular manipulator of food
• papillae and taste buds on the dorsal surface
• lingual glands secrete saliva, tonsils in root

Answer 24

Tongue

Question 25

* allow breathing and chewing at the same time * palatoglossal and palatopharyngeal arches

Answer 25

Hard and soft palate

Question 26

baby teeth adult teeth

Answer 26

20 32

Question 27

Tooth Structure

Answer 27

* The periodontal ligament is modified periosteum * Cementum and dentin are living tissue * Enamel is a noncellular secretion formed during the development * Root canal leads into the pulp cavity Gingiva or gums

Question 28

Breaks food into smaller pieces to be swallowed

Answer 28

Mastication or Chewing

Question 29

function of Saliva:

Answer 29

* moisten * begin starch and fat digestion * cleanse teeth * inhibit bacteria, bind food together into the bolus

Question 30

Small intrinsic glands found under mucous membrane of mouth, lips, cheeks and tongue - secrete at constant rate

Answer 30

Salivary Glands

Question 31

3 pairs extrinsic glands connected to oral cavity by ducts:

Answer 31

* parotid gland - largest * submandibular gland * sublingual gland

Question 32

Mucous cells secrete _______

Answer 32

Mucus

Question 33

Serous cells secrete ____________

Answer 33

thin fluid rich in amylase

Question 34

salivary glands produce thin saliva, rich in enzymes

Answer 34

parasympathetic stimulation

Question 35

produce less abundant, thicker saliva, with more mucus

Answer 35

sympathetic stimulation

Question 36

Higher brain centers stimulate salivatory nuclei so sight, smell and thought of food cause __________

Answer 36

Salivation

Question 37

Pharynx

Answer 37

* Skeletal muscle * deep layer – longitudinal orientation * superficial layer – circular orientation * superior, middle and inferior pharyngeal constrictors

Question 38

Straight muscular tube 25-30 cm long

Answer 38

Esophagus

Question 39

Series of muscular contractions coordinated by center in medulla and pons

Answer 39

Swallowing (Deglutition)

Question 40

tongue collects food and pushes it back into oropharynx

Answer 40

Buccal phase

Question 41

* soft palate rises and blocks nasopharynx * infrahyoid muscles lift the larynx; epiglottis folded back * pharyngeal constrictors push bolus down the esophagus

Answer 41

Pharyngeal-esophageal phase

Question 42

Mechanically breaks up food, liquifies food and begins chemical digestion of protein and fat Muscular sac (internal volume from 50ml to 4L)

Answer 42

Stomach

Question 43

opening to duodenum

Answer 43

Pylorus

Question 44

domed portion superior to esophageal opening

Answer 44

fundus

Question 45

main portion of organ

Answer 45

Body

Question 46

narrow inferior end

Answer 46

pyloric region

Question 47

Pylorus is a thick ring of smooth muscle that forms a __________

Answer 47

sphincter

Question 48

* simple columnar glandular epithelium * lamina propria is filled with tubular glands (gastric pits)

Answer 48

Mucosa

Question 49

Muscularis externa has 3 layers:

Answer 49

* outer longitudinal layer * middle circular layer * inner oblique layer