Chapter 11 Flashcards

1
Q

Prehension

A

The first step of digestion.

The seizing and conveying of food to the mouth

Delivered to the mouth

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2
Q

Means of Prehension

A

Biped - Man & Apes; use our upper limbs, arms and hands

Quadrupeds - Domestic Animals; use mouth, teeth and lips, trunks etc.

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3
Q

Carnivores

A

Rely on teeth for ripping and tearing of flesh and meat.

Canine teeth, they have strong jaws and upper and lower molars

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4
Q

Cow - Ruminants

A

Mobile tongue; used to seize grass

Dental pad; no upper incisors but they do have lower incisors

Upper and lower molars for mastication

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5
Q

Sheep - ruminant

A

Mobile lip (cleft lip) - nibble more

Dental pad - no upper incisor

Graze closer than a cow and more selective than a cow

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6
Q

Horse - monogastrics

A

Mobile lips
Nibbles
Upper and lower incisors - can bite through food
Graze closer than a cow

Must chew thoroughly the first time. Cannot regurgitate

Horses teeth must be checked for proper alignment. Molars need to grind against one another

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7
Q

Avians

A

No lips
No teeth
Extreme diversity for seizing and conveying of food

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8
Q

Mastication

A

Vertical movements of the jaw which crush the food particles between teeth

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9
Q

Mastication for carnivores

A

Reduce the meal enough so that is can be swallowed

Rip, tear, swallow

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10
Q

Mastication for omnivores

A

Chew more than carnivores

Pigs - limited, don’t chew a lot

Avian - no teeth, no mastication

Humans - “slow down and chew your food”

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11
Q

Mastication for herbivores

A

Chew extensively

Need thorough mastication for their feed

Reduce particle size so it can move in GI tract

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12
Q

Mastication for herbivore ruminants

A

Chew extensively and then form a bolts, swallow and will go into the rumen, regurgitate and masticate more and will go back into rumen and ruminante. This process will continue

Typical dairy cow may chew about 42K times a day

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13
Q

Salivation

A

Produced by all animals
Secretion and mixing saliva with food

3 main paired salivary glands
Parotid - beneath ears
Submandibular - either side of jaw
Sublingual - under tongue

Amount of saliva produced varies with species, nature of diet, health of animal , etc.

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14
Q

Salivation in carnivores

A

Small amounts because they consume wet feed, about 200 ml/d

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15
Q

Salivation in omnivores

A

Varied, 1,500 ml/d

Depends on how much they chew

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16
Q

Salivation in herbivores

A

Horse about 40 liters
Cows about 60 liters
High producing dairy cows about 150 liters a day

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17
Q

Composition of saliva

A

Varies with species, diet, age, and health of animals

99% water
Mucin (mucus)
Electrolytes - Na & K

Salivary Amylase - enzyme that breaks down starch
Present in - man, apes, pigs, rats, some Avians
Not present in - cattle, dogs, cats or horses

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18
Q

Functions of Saliva

A

Lubrication of food
Acts as a solvent - dissolved food into solution allows food to mid with taste buds
Cleans oral cavity - inhibits growth of bacteria
Washes dental cavity
Buffer for NaCO3 in ruminants and providing nitrogen and phosphorus for fermentation in ruminants

19
Q

Swallowing or Deglutition

A

Reflex of passing anything from the mouth through the esophagus to the stomach

Neural reflex:
Voluntary - first 1/3 of the process and involuntary - last 2/3 of process

20
Q

Steps in Deglutition

A
  1. Neural reflex
    - voluntary
    - involuntary
  2. Bolus of food moves down via peristaltic wave
  3. At the end of the esophagus there is the cardiac sphincter - does not allow reflux up and helps prevent committing. Ruminants do not have a cardiac sphincter.
21
Q

Fundic or cardiac region

A

Upper section of the stomach

Secretes mucus and HCL

22
Q

Body or proper gastric

A

Middle part of the stomach

Secretes HCL and Pepsinogen

23
Q

Pyloric

A

Bottom part of the stomach

Secretes mucus and pepsinogen

24
Q

Gastric Pits

A

Neck cells - top; produce mucus

Parietal cells - middle; HCL (we don’t want it active) produces through carbon anhydride

Chief cells - bottom; pepsinogen

HCL is not produced until it’s in the lumen

25
Stomach
Pigs, humans, dogs, (monogastrics) - glandular stomach Chicken - proventriculus Cows, sheep, ruminants - abomasum All three types of digestion are at work- mechanical, chemical and enzymaticp
26
Mechanical digestion in the stomach
Muscular contractions that churn the digesta Mixes the digesta with enzymes and chemicals
27
Chemical digestion in stomach
Gastric glands - parietal cells produces HCL HCL unfolds proteins - exposes the proteins to enzymes. Activates enzymes in the stomach. Optimal pH (2-2.5) pepsin works best Helps destroy bacteria - except food borne illnesses
28
Enzymatic digestion in the stomach
For the most part occurs by pepsin which is a protease. Proteases work on proteins, hydrolysis proteins Pepsin producers by Chief cells, cleaves protein and makes shorter chain lengths. Rennin - acts on milk protein (young)
29
Functions of stomach
Storage - stores for a period of time | Metering - meters or limits movement of digesta into Intestines
30
What keeps the stomach from digesting itself?
Mucin - secretes by neck cells and provides protection or coating HCL is diluted in the stomach by saliva and digestion - food and saliva helps to buffer Urease - enzyme that breaks down urea - acts as a buffer as well Enzyme is secretes in an inactive form (zymogen). Only active in lumen if stomach
31
Small intestine
Divided into 3 parts Duodenum Jejunum Ileum
32
Duodenum
First segment of SI Extends from pyloric sphincter to jejunum Primary site of digestion
33
Jejunum
Second segment of SI Extends from duodenum to ileum Primary site for absorption
34
Ileum (terminal ileum)
Last segment of SI - smallest part Extends from jejunum to large intestine Secondary site of absorption
35
Bile
Made in the liver and stored in the gall bladder Functions in two ways: Detergent action - solubilizes fat Forms complex with fatty acids Secreted into duodenum
36
Pancreatic juice
Secretion from pancreas that contains very potent digestive enzymes Secreted into duodenum ``` Main enzymes are Trypsin and Chymotrypsin - digestion Carboxypeptidase - digestion Pancreatic lipase - fat Amylase - starch ``` Contains buffers - HCO3 & NaCO3 - both neutralize acidic pH
37
Duodenal juice
Secreted by brush border | Contains enzymes secreted by intestinal mucosa
38
Large Intestine
The contents of the LI are not sterile - bacteria, Protozoa, fungi Digestion is limited by mco Absorption is limited - VFA, water and electrolyte
39
LI - Monogastric Herbivores
Horse, rabbit, guinea pig and elephant - extensive cecum and colon - provide good environment for mco The LI of adult horses are comparable in size to the rumen in ruminants
40
LI and Ceca in monograstrics herbivores
Similar to fermentation in rumen but not as efficient Because most of nutrient content is removed by the SI and past the site of primary absorption
41
Corophagy
Feeding on excrement Rabbits and other species practice. Two types of feces Pellet type Soft feces Contains B vitamins and MCO protein
42
Defecation
Discharge of excrements from rectum it cloaca ``` Contents of decal material - Water Undigested feed Residues of digestive enzymes Sloughed cells Bacteria ```
43
Urination
``` Components of urine - Water Minerals - Cl, K, P, Na Nitrogen compounds - Urea - animals (livestock) Uric acid - birds Ammonia Will also include electrolytes Glucose and small carbohydrates ```
44
Substances found in urine
Should generally be considered waste produces if metabolism rather than digestion