L1 & L2: Comparative GIT Anatomy Flashcards Preview

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Flashcards in L1 & L2: Comparative GIT Anatomy Deck (15)
1

Food is considered to be outside the body until nutrients are absorbed by the small intestine. T or F?

True, of course

2

Describe the basic differences in the GIT b/w different species and how these differences relate to diet

3

Describe the process of motility

  • Mixing of ingested material with secretions
  • Peristalsis - contraction of smooth muscle of digestive tract to move food along (squeeze behind, relax in front). All animals do this.
  • Rate of food movement depends of feed & species
  • Rumen & reticulum have convulsive motility "waves"

4

Describe the process of digestion

  • Breakdown of food into constitutent molecules small enough to be absorbed
    -physical (mechanical)
    -chemical (enzymatic)
  • Aided by digestive secretions (enzymes) and mixing (motility)

5

Describe the process of secretion

  • Release of substances within the body to aid digestion
    -enzymes
    -buffers
    -bile salts (emulsify fats)
    -lubricants
    -solvents

6

Describe the process of absorption

  • Needs to occur for body to use nutrients
  • Occurs across specialised absorptive cells lining lumen
  • Either passive (diffusion) or active (carrier mediated)

7

Basic components of mammalian digestive tract

The mouth, lips, teeth and tongue are used for?

prehension and mastication, lubricating

8

Basic components of mammalian digestive tract

Describe the pharynx and oesophagus

  • Common passage for food and air
  • pharyngeal muscles force food from pharynx

9

Basic components of mammalian digestive tract

Describe the monogastric stomach and its role

 

  • Lying under diaphragm
  • separated from oesophagus by cardiac sphincter
  • separated from SI by pyloric sphincer

    Role:
  • Mix food
  • reservoir of material supply to SI
  • begins digestion by secreting gastric juices
  • Digesion occurs primarily via HCL from parietal cells
  • Pepsinogen (inactive form of Pepsin -protein digestor) secreted by chief cells
  • Pepsinogen activated by low pH (HCL)
  • glandular digestion

 

10

Basic components of mammalian digestive tract

Describe the monogastric stomach glands

  • 1. Cardiac glands => mucus
  • 2. Fundic (gastric) glands => mucus, HCL, pepsinogen (pepsin)
  • 3. Body => gastric digestion
  • 4. Pyloric glands => mucus, sml amount pepsinogen

 

11

Basic components of mammalian digestive tract

Describe avian GIT

  • Glandular (true) stomach is proventriculus
  • Followed by ventriculus (gizzard)
  • Cloaca -passes faeces & urine mixed

 

12

Basic components of mammalian digestive tract

Describe the ruminant stomach and its components

  • Digest cellulose & CHD
  • 4 compartments, 3 sections
    -fore-stomach (reticulum & rumen) => microbial fermentation
    -Bible (omasum) => water absorption
    -True stomach (abomasum) => glandular
  • Reticulo-rumen contains water & microbes at alkaline pH and warm temp
  • Rumen has villied surface, absorb VFA
  • Reticulum has honey comb surface increase breakdown
  • Omasum, absorbs water & some VFA

 

13

Basic components of mammalian digestive tract

describe the SI

  • digesta moves quickly ~about 30cm/min
  • Mobile
  • 3 parts
    -duodenum: pancreatic & bile ducts empty into
    -jejunum: absorb carbs & protein (villi, micro-villi, brush border)
    -ileum:

14

Basic components of mammalian digestive tract

describe the LI

  • 3 parts
    -Caecum
    -Colon (large and small)
    -Rectum
  • L colon: 4 regions, site of most fermentation (VFA)

 

15

Basic components of mammalian digestive tract

list the accesory digestive organs and briefly describe their role

  • Salivary glands: parotid, mandibular, sublingual (major)
  • Liver: secretes bile, energy storage (glycogen), processes absorbed nutrients, breakdown of RBC (bilirubin)
  • Pancreas:
    -exocrine secretes via ducts (sodium bicarb & digestive enzymes). Outside body.
    -endocrine secretes into blood (ductless) hormones insulin, glucagon, somatostatin
  • Associated SI glands:
    -Brunner's glands
    -Crypts of Lieberkuhn
    -Peyer's patches