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Flashcards in chapter 23 Deck (42)
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1
Q

Alimentary canal =

A

gastrointestinal (GI) tract

2
Q

basic digestive functions

A
ingestion
propulsion
mechanical digestion
chemical digestion
absorption 
defecation
3
Q

the movement of materials through the alimentary canal

* ex. Peristalsis

A
  1. Propulsion-
4
Q

the physical breakdown of food (from solid to liquid form)

* ex. Mastication

A

Mechanical digestion-

5
Q

the use of chemicals (like enzymes) to break food down into individual monomers

* Carbs —> monosaccharides 
* Proteins —> amino acids
A

Chemical digestion

6
Q

the passage of materials from the alimentary canal into the blood

A

Absorption-

7
Q

release of undigested, unabsorbed materials from the colon

A

Defecation-

8
Q

The Alimentary Canal has its own (nervous system)

A

enteric nervous system (ENS)

9
Q

the ENS can do what on its own

A

Which can integrate some digestive process on its own (without the CNS)

10
Q

When the ENS integrates information on its own (without using the CNS), the process resulting from this integration is called

A

a short reflex

11
Q

When a digestive process occurs as the result of the CNS performing integration, that process is called

A

a long reflex

12
Q

Deglutition two phases

A

buccal phase

pharyngeal-esophageal phase

13
Q
  • Buccal phase (voluntary)
A
  • Tongue moves food into pharynx
14
Q
  • Pharyngeal-esophageal phase (involuntary)
A
  • Pharyngeal constrictor muscles move food into esophagus
15
Q
  1. Mechanical activities are Performed by
A

muscularis externa)

16
Q

stomach expands as food enters esophagus

A
  1. Filling(receptor relaxation)
17
Q
  1. As food enters stomach, stomach continues to expand
A

(adaptive relaxation)

18
Q
  1. Mechanical digestion-
A

3-4 times/minute, peristaltic waves travel from fundus —> pylorus, which converts food into chyme and moves 3-5ml of chyme into duodenum with each wave

19
Q
  1. Secretion of gastric juice from what glands
A

(by gastric glands of the stomach mucosa)

20
Q
  • mucous cells
A

release mucus that protects stomach lining from acidity

21
Q
  • Parietal cells-
A

Parietal cells also release intrinsic factor, a glycoprotein necessary in the absorption of vitamin B12. Release HCL which helps destroy microorganisms and toxins

22
Q
  • Chief cells-
A

release the protein pepsinogen, the inactive form of the enzyme pepsin which preforms protein digestion. Also release an enzyme called gastric lipase- fats

23
Q

G cells-

A

release the hormone gastrin- stimulates cells of gastric glands. Helps stomach muscularis reach threshold and begin mechanical digestion

24
Q

3 phases of gastric juice secretion

A

cephalic
gastric
intestinal

25
Q

Cephalic phase

A

smell, sight, taste or thought —> cerebral cortex to the hypothalamus to (vagus) gastric juice secretion

26
Q

gastric phase

A
  1. food enters stomach —> G cells detect food chemicals —> G cells release gastrin —> gastric juice secretion
    1. Food enters stomach —> stomach mechanoreceptors detect physical presence of food —> hypothalamus —> vagus —> gastric food secretion
27
Q
  1. Intestinal phase-
A

as food enters duodenum, stimulates stomach using intestinal gastrin
1. As soon as duodenum is full of chyme, stomach gets inhibited as part of the enterogastric reflex —> hypothalamus closes pyloric sphincter. Duodenum temporarily inhibits stomach movements with the hormones secretin, CCK

28
Q
  • Major site of chemical digestion
A

small intestine

29
Q
  • Small intestine releases digestive enzymes called
A

brush border enzymes (BBE’s) which perform the final steps of polymer digestion

30
Q
  • Carbohydrates-
A
  • very large polysaccharides
    • smaller polysaccharides; salivary amylases.
    • Disaccharides; Pancreatic enzymes
    • Monosaccharides; BBE’s
31
Q
  • Major site of absorption
A

small intestine

32
Q

folds in small intestine

A
  • Has an enormous surface area that is ideal for absorption; plicae (small folds)
    • Villi (more smaller folds)
    • Microvilli (even smaller folds)
33
Q
  • Performs mechanical digestion (segmentation)
A

small intestine

34
Q

small intestine contents emptying

A
  • Empties its contents into large intestine via gastrointestinal reflex
35
Q

small intestine food enters stomach…

A

Food enters stomach —> hypothalamus —> vagus —> small intestine empties contents into large intestine; intestinal

36
Q

liver

A
  • Receives nutrient rich blood directly from GI tract
37
Q

what hepatocytes do

A
  • Identify and detoxify/destroy drugs, toxins, microorganisms
    • Process nutrients- use amino acids to make plasma proteins
    • Stores glucose as glycogen
    • Make bile, which aids in chemical digestion of fats
38
Q

gall bladder use

A

store and release bile (in response to CCK)

39
Q

Pancreas use

A
  • Release pancreatic juice
    • Contrains alkaline solution
    • Contrains digestive enzymes
      • Amylases
      • Lipases
      • Proteases
      • Nucleases (DNA, RNA)
40
Q

large intestine use

A
  • Some chemical digestion (mostly tough carbs like cellular)
  • Some absorption (mostly water)
  • Mechanical actives
  • Mass movements
    defectation reflex
41
Q
  • Mechanical actives
A
  • Haustral contractions
42
Q
  • Mass movements
A
  • 3-4 times a day
    • Move feces into sigmoid colon
    • Occurs as part of gastrocolic reflex