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Flashcards in Chapter 11 Deck (44)
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1
Q

Prehension

A

The first step of digestion.

The seizing and conveying of food to the mouth

Delivered to the mouth

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.

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

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

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

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

7
Q

Avians

A

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

8
Q

Mastication

A

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

9
Q

Mastication for carnivores

A

Reduce the meal enough so that is can be swallowed

Rip, tear, swallow

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”

11
Q

Mastication for herbivores

A

Chew extensively

Need thorough mastication for their feed

Reduce particle size so it can move in GI tract

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

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.

14
Q

Salivation in carnivores

A

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

15
Q

Salivation in omnivores

A

Varied, 1,500 ml/d

Depends on how much they chew

16
Q

Salivation in herbivores

A

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

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

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
Q

Stomach

A

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
Q

Mechanical digestion in the stomach

A

Muscular contractions that churn the digesta

Mixes the digesta with enzymes and chemicals

27
Q

Chemical digestion in stomach

A

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
Q

Enzymatic digestion in the stomach

A

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
Q

Functions of stomach

A

Storage - stores for a period of time

Metering - meters or limits movement of digesta into Intestines

30
Q

What keeps the stomach from digesting itself?

A

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
Q

Small intestine

A

Divided into 3 parts
Duodenum
Jejunum
Ileum

32
Q

Duodenum

A

First segment of SI Extends from pyloric sphincter to jejunum
Primary site of digestion

33
Q

Jejunum

A

Second segment of SI
Extends from duodenum to ileum
Primary site for absorption

34
Q

Ileum (terminal ileum)

A

Last segment of SI - smallest part
Extends from jejunum to large intestine
Secondary site of absorption

35
Q

Bile

A

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
Q

Pancreatic juice

A

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
Q

Duodenal juice

A

Secreted by brush border

Contains enzymes secreted by intestinal mucosa

38
Q

Large Intestine

A

The contents of the LI are not sterile - bacteria, Protozoa, fungi

Digestion is limited by mco
Absorption is limited - VFA, water and electrolyte

39
Q

LI - Monogastric Herbivores

A

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
Q

LI and Ceca in monograstrics herbivores

A

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
Q

Corophagy

A

Feeding on excrement

Rabbits and other species practice.

Two types of feces
Pellet type
Soft feces

Contains B vitamins and MCO protein

42
Q

Defecation

A

Discharge of excrements from rectum it cloaca

Contents of decal material - 
Water
Undigested feed 
Residues of digestive enzymes 
Sloughed cells 
Bacteria
43
Q

Urination

A
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
Q

Substances found in urine

A

Should generally be considered waste produces if metabolism rather than digestion