Fundamentals of Anatomy & Physiology: A&P II Chapter 24: The Digestive System Flashcards


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1

Anabolism

nutrients are used as raw materials for synthesizing essential compounds

2

Catabolism

decomposes substances to provide energy cells need to function

3

Catabolic Reactions

-requires two essential ingredients

  1. Oxygen
  2. Organic molecules ( such as carbohydrates, fats, and proteins) broken down by intracellular enzymes
4

The Digestive Tract

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  • aka the gastrointestinal (GI) tract or alimentary canal
  • is a muscular tube
  • includes the mouth, pharynx, esophagus, stomach, and small and large intestines
  • extends from the oral cavity to the anus
5

Accessory Digestive Organs

  • teeth
  • tongue
  • salivary glands
  • liver
  • gallbladder
  • pancreas
6

6 Functions of the Digestive System

  1. Ingestion
  2. Mechanical Processing
  3. Digestion
  4. Secretion
  5. Absorption
  6. Excretion
7

Ingestion

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  • takes place when materials enters the oral cavity
8

Mechanical Processing

  • crushing and shearing, making materials easier to move along the digestive tract
9

Digestion

  • the chemical breakdown of food into small organic fragments for absorption by digestive epithelium
10

Secretion

  • the release of water, acids, enzymes, buffers, and salts by the epithelium of the digestive tract & glandular organs
11

Absorption

  • the movement of organic substrates, electrolytes, vitamins, and water across digestive epithelium and into interstitial fluid of the digestive trace
12

Excretion

the removal of wastes from the body

*defecation

13

Defecation

ejection of wastes from the digestive tract eliminating them as feces

14

Serosa or Visceral Peritoneum

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covers organs within peritoneal cavity

15

Parietal Peritoneum

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lines inner surfaces of body wall

16

Peritoneal Fluid

  • produced by the serous membrane lining
  • provides essential lubrication
  • separates parietal and visceral surfaces, allowing sliding without friction or irritation
17

Ascites

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  • excess peritoneal fluid causing abdominal swelling
18

Mesenteries

  • double sheets of peritoneal membrane
  • suspend portions of the digestive tract within the peritoneal cavity by sheets of serous membrane that connect parietal and visceral peritoneum
  • stabilize positions of attached organs
  • prevent intestines from being entangled
19

Areolar Tissue Between Mesothelial Surfaces

-provides an access route to and from the digestive tract for passage of blood vessels, nerves, and lymphatic vessels

20

The Lesser Omentum

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  • fat skin
  • stabilizes the position of the stomach
  • provides an access route for blood vessels and other structures entering or leaving the liver
  • attaches stomach to liver
21

The Falciform Ligament

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  • helps stabilize the position of the liver, relative to the diaphragm and abdominal wall
22

The Dorsal Mesentery

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  • enlarges to form an enormous pouch, called the greater omentum
23

The Greater Omentum

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  • extends inferiorly between the body wall and the anterior surface of the small intestine
  • hangs like an apron, from the inferior and lateral borders of the stomach
24

Adipose Tissue in the Greater Omentum

  • conforms to shapes of surrounding organs
  • provides padding & protection
  • insulates to reduce heat loss
  • stores lipid energy reserves
25

The Mesentery Proper

  • suspends all but the first 25 cm of small intestine
  • thick mesenterial sheet
  • provides stability, but permits SOME independent movement
  • associated with the duodenum and pancreas
  • fuses with posterior abdominal wall, locking structures in position
26

Four Layers of the Digestive Tract

  1. mucosa
  2. submucosa
  3. muscularis externa
  4. serosa
27

The Mucosa

  • the inner lining of digestive tract
  • mucous membrane
  • consists of epithelium, moistened by glandular secretions
  • lamina propria of areolar tissue
28

The Digestive Epithelium

  • mucosal epithelium is either simple or stratified depending on the location, function, and stresses
29

Lined with Stratified Squamous

  • oral cavity
  • pharynx
  • esophagus
30

Lined with Simple Columnar Epithelium

  • for absorption
  • stomach
  • small intestine
  • most of the large intestine
  • contains mucous cells
31

Enteroendocrine Cells

  • scattered amongst columnar cells of the digestive tract
  • secrete hormones that coordinate the activities of the digestive tract
32

Lining of the Digestive Tract

  • appears as longitudinal folds, which disappears as the tract fills
  • folding increases the surface area available for absorption
33

The Lamina Propria

  • layer of areolar tissue
  • contains:
    1. blood vessels
    2. sensory nerve ending
    3. lymphatic vessels
    4. smooth muscle cells
    5. scattered areas of lymphoid tissue
34

The Muscularis Mucusae

  • narrow sheet of smooth muscle and elastic fibers in lamina propria
  • cells are arranged in two concentric layers
35

The Submucosa

  • layer of dense irregular connective tissue
  • binds the mucosa to the muscularis externa
  • has numerous blood and lymphatic vessels
  • some regions contains exocrine glands that secrete buffers and enzymes into the lumen of the digestive tract
36

Submucosal Plexus

  • aka Meissner plexus
  • network of intrinsic nerve fibers and scattered neurons
  • contains sensory neurons, parasympathetic ganglionic neurons, and sympathetic postganglionic fibers
37

The Muscularis Externa

  • smooth muscles dominates this region
  • cells are arranged in circular layer and outer longitudinal layer