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Anatomy II > Digestive System > Flashcards

Flashcards in Digestive System Deck (65):
1

Mechanical Digestion

Physical breakdown of food into smaller particles

Teeth and churning action of stomach and intestines

2

Chemical Digestion

Series of hydrolysis reactions that break macromolecules into their monomers

Enzymes from saliva, stomach, pancreas, and intestines

3

Results of Chemical Digestion

Polysaccharides into monosaccharides
Proteins into amino acids
Fats into glycerol and fatty acids

4

Which buffer system uses HPO4 to buffer secreted acid in the kidney?

The Phosphate Buffer System

5

What is responsible for the detection of blood osmolarity?

Osmoreceptors located in the hypothalamus

6

What does not elicit the release of aldosterone?

ADH
Does not have anything to do with sodium

7

Subdivisions of the Digestive System

Digestive tract and accessory organs

8

Digestive Tract

16 foot long tube extending from the mouth to anus

9

Accessory Organs

Aid in digestion but are not part of the alimentary canal

Teeth, tongue, liver, gallbladder, pancreas, salivary glands

10

Layers of the GI Tract

1. Mucosal layer
2. Submucosal layer
3. Muscularis layer
4. Serosa layer

11

Mucosa

Inner lining
Stratified squamous epithelium, simple columnar epithelium, lamina propria, muscularis mucosae

12

Stratified Squamous Epithelium

In mouth, esophagus, and anus
Tough

13

Simple Columnar Epithelium

Secretes enzymes and absorbs nutrients
Specialized cells (goblet cells) secrete mucous onto cell surface
Enteroendocrine cells secrete hormones controlling organ function

14

Lamina Propria

Thin layer of loose connective tissue
Contains blood vessels and lymphatic tissue

15

Muscularis Mucosae

Thin layer of smooth muscle
Causes folds to form in mucosal layer
Increases local movements increasing absorption with exposure to "new" nutrients

16

Submucosa

Loose connective tissue containing blood vessels, glands, and lymphatic tissue
Meissner's Plexus: parasympathetic, causes vasoconstriction

17

Muscularis

Skeletal muscle for voluntary control in mouth, pharynx, upper esophagus, and anus
Smooth muscle for mixing, crushing, and propelling food by peristalsis
Auerbach's Plexus for sympathetic and parasympathetic innervation of smooth muscle layers

18

Serosa

Serous membrane
Covers all organs and walls of cavities not open to the outside of the body
Secretes slippery fluid
Consists of connective tissue covered with simple squamous epithelium

19

Peritoneum

Visceral layer covers organs
Parietal layer lines the walls of the body cavity

20

Greater Omentum

Prevents organs from moving around
Hangs down from the stomach
Contains blood and lymphatic vessels

21

Mesocolon

Connects intestines together

22

Lesser Omentum

Connects stomach to liver
"Beer belly"

23

Lips and Cheeks

Contain buccinator muscle that keeps food between upper and lower teeth

24

Oral Cavity Proper

Hard palate, soft palate, and uvula

25

Tongue

Responsible for moving food
Attached to hyoid, mandible, hard palate, and styloid process

26

Tooth Structure

1. Crown
2. Neck
3. Roots
4. Pulp cavity

27

Composition of Teeth

Enamel
Dentin
Cementum

28

Enamel

Hardest substance in the body
Calcium phosphate or carbonate

29

Dentin

Calcified connective tissue

30

Cementum

Bone-like
Periodontal ligament penetrates it

31

Saliva

Moistens, dissolves food for taste, begins starch and fat digestion, cleanses teeth, inhibits bacteria, and binds food together into bolus

32

Amylase

Begins starch digestion

33

Lingual Lipase

Digests fat after it reaches the stomach

34

Lysozyme

Enzyme that kills bacteria

35

Immunoglobin A

Inhibits bacterial growth

36

Electrolytes

Na+, K+, Cl-, phosphate, and bicarbonate

37

Salivation

Salivary nuclei in the medulla oblongata and pons
Parasympathetic function

38

Mumps

Myxovirus that attacks the parotid gland

39

Pharynx

Funnel-shaped tube extending from internal nares to the esophagus (posteriorly) and the larynx (anteriorly)

40

Esophagus

Collapsed muscular tube

41

Histology of the Esophagus

Mucosa: stratified squamous
Submucosa: large mucous glands
Muscularis: upper 1/3 is skeletal, middle is mixed, lower 1/3 is smooth
Adventitia: connective tissue blending with surrounding connective tissue (no peritoneum)

42

Swallowing

Upper sphincter relaxes when larynx is lifted
Peristalsis pushes food down
Lower sphincter relaxes as food approaches

43

Swallowing: Oral Phase

Voluntary
Bolus formed in the mouth
Oropharynx-->Laryngopharynx

44

Pharyngeal Phase

Involuntary
Tongue and soft palate block food and drink
Esophagus widens

45

Esophageal Phase

Peristalsis
Brain swallowing center + myenteric plexus in esophageal wall
Muscle above bolus constricts

46

Anatomy of Stomach

Left side of stomach
Cardia, Fundus, Body, Pylorus

47

Pylorospasm

Muscle fibers of sphincter fail to relax, trapping food in the stomach
Vomiting occurs to relieve pressure

48

Pyloric Stenosis

Narrowing of sphincter indicated by projectile vomiting
Must be corrected surgically

49

Stomach Mucous Cell

Secretes mucous
Cardiac, pyloric glands

50

Stomach Regenerative Cells

Base of gastric pits
Divide rapidly
New cells migrate upward

51

Stomach Parietal Cells

Secrete HCl, intrinsic factor, ghrelin
Found mostly in gastric glands

52

Stomach Chief Cells

Most numerous
Secrete gastric lipase, pepsinogen
Lower 1/2 of gastric glands

53

Stomach Enteroendocrine Cells

Found in the lower end of the gland
Secrete hormones and paracrine messengers
At least 8 different kinds

54

Stomach Muscularis

Longitudinal, Circular, and Inner Oblique

55

Stomach Mechanical Digestion

Gentle mixing waves
More vigorous waves from body to pyloric region
Intense waves near the pylorus

56

Stomach Chemical Digestion

Protein digestion begins as HCl denatures protein, transforms pepsinogen into pepsin
Fat digestion continues as gastric lipase splits triglycerides in milk fat

57

Regulation of Gastric Secretion and Motility

1. Cephalic phase
2. Gastric phase
3. Intestinal phase

58

Cephalic Phase

Gets the stomach ready
Cerebral cortex stimulates parasympathetic nervous system
Vagus nerve increases stomach muscle and glandular activity

59

Gastric Phase

"Stomach Working"
Nervous control keeps stomach active
Endocrine system influences stomach activity

60

GI Reflexes

Short Reflex: reflex arc where stimulus, integration, and effector are all located in the GI system
Long Reflex: reflex arc where integration occurs in the brain or spinal cord; vasovagal reflex

61

Functions of Hydrochloric Acid

1. Activates enzymes pepsin and lingual lipase
2. Breaks up connective tissues and plant cell walls
3. Converts ingested ferric ions to ferrous ions that can be used for hemoglobin
4. Destroys ingested bacteria and pathogens

62

Intrinsic Factor (Parietal Cells)

Essential for absorption of B12 by small intestine
Necessary for RBC production (pernicious anemia)

63

Pepsin (Chief Cell)

Secreted as pepsinogen
HCl converts it to pepsin, which activates more pepsinogen

64

Gastric Lipase (Chief Cell)

Gastric lipase + lingual lipase digests 10-15% of dietary fat
Remainder in the small intestine

65

Intestinal Phase

Gastric activity INCREASES
Enterogastric reflex=duodenum INHIBITING stomach
Chyme stimulates duodenal cells to release SECRETIN, CCK, and GASTRIC INHIBITORY PEPTIDE to SUPPRESS gastric secretion and motility