Food ingestion

Question 1

What is prehension?

Answer 1

Grasping of the food by lips or tongue.

Question 2

What is mastication?

Answer 2

Breaking down the food by teeth and tongue.

Question 3

What is the point of mastication?

Answer 3

Break the food to swallowable bites and impregnate it with saliva.

Question 4

What is salivation?

Answer 4

Lubrication of food by impregnating it with saliva.

Question 5

What are the secretions of saliva?

Answer 5

Serous (alpha-amylase for starch digestion) and mucus secretion (mucin for lubrication and surface protection).

Question 6

Where is saliva produced?

Answer 6

Salivary glands: parotid (serous), mandibular (mixed), sublingual (mucus), and zygomatic (mixed).

Question 7

What are acini?

Answer 7

Basic secretory units of salivary glands are clusters of cells called acini.

Question 8

What are the steps of saliva production?

Answer 8

First secretory step: acini cells secrete amylase, mucin and electrolytes in the same concentration as plasma (isotonic fluid)
Second secretory step: modification by the duct cells
Active Na + reabsorption (vs K +)
-> saliva becomes hypotonic with respect
to plasma.

Question 9

What is the chemical compostion of saliva?

Answer 9

H20 (97-99.5%
organic ions as in blood
mucine for lubrication
bicarbonate for rumen buffer
urea for ruminants
Organic products for antibacterial activity: IgA, lactoferrin, lisozyme
Enzymes: alpha-amylase and lingual lipase

Question 10

What is alpha amylose?

Answer 10

Begins the digestion of carbohydrates in mouth

Question 11

How is salivation regulated?

Answer 11

By ANS: sympathetic and mostly parasympathetic innervations stimulates saliva prosuction.

Question 12

How much saliva is secreted?

Answer 12

Horses: 40 L
Normal cows: 60 L
High production cows: 120–200 L
Sheep: 10 L
Pig: 5-10 L

Question 13

What is deglutition?

Answer 13

Swallowing bolus by transporting it from the mouth through the pharynx and oesophagus into the stomach.

Question 14

What are the 3 steps of deglutition?

Answer 14

1. voluntary stage: initiates the process
2. Pharyngeal stage: involuntary, passage of food from the pharynx into the oesophagus
3. Oesophagal stage: involuntary, transport to the stomach.

Question 15

How does the deglutition reflex work?

Answer 15

The swallowing centre localized in
medulla oblongata:
-Sensitive information (afferent) from
pharynx (glossopharyngeal and
trigeminal nerve)
-When stimulated deglutition reflex
starts automatically.
-Efferent information with motor
impulses go back to pharynx and
oesophagus (vagus, trigeminal and
glossopharyngeal nerves)

Question 16

What are the esophagous movements?

Answer 16

Primary and secondary peristalsis.

Question 17

Explain the secondary peristalsis.

Answer 17

Stretching of the walls of the oesophagus, the contraction starts. These waves continue until all the food has emptied into the
stomach. Controlled by the enteric nervous system.

Question 18

Explain the primary peristalsis.

Answer 18

It is a continuation of the peristaltic wave that begins in the pharynx and spreads into the oesophagus during the pharyngeal stage of
swallowing. This wave passes all the way from the pharynx to the stomach in
about 8 to 10 seconds. It is controlled by the enteric nervous system and extrinsic
nervous control.