Digestion

Question 1

Insects can employ two different types of digestion, what are they?

Answer 1

1. Internal
2. External

Question 2

Describe the digestive process in insects

Answer 2

Food is ingested in the form of macromolecules which need to be broken down by catabolic reactions into smaller molecules before being used by cells in the body

Question 3

What does the digestive system lead to in insects?

Answer 3

The breakdown of polymers into monomers

Question 4

What are the three main polymers?

Answer 4

1. carbohydrates are polymers of simple sugars
2. nucleic acids are polymers of nucleotides
3. proteins are polymers of aminoacids

Question 5

Where is the digestive system in an insect?

Answer 5

It is a tube that runs from the mouth to the anus

Question 6

In most insects, the alimentary canal is subdivided into 3 regions

Answer 6

1. Foregut
2. Midgut
3. Hindgut

Question 7

The foregut and midgut are lined by what?

Answer 7

Cuticle

Question 8

Describe the foregut

Answer 8

Also known as the PROVENTRICULUS. It is a grinding structure with rows of cuticular teeth and strongly developed layers of ring and longitudinal muscles. This device is used for a mechanical processing of the food.

Question 9

What happens in the midgut?

Answer 9

Digestion

Question 10

The hindgut consists of…

Answer 10

anterior hindgut and rectum, to
reabsorb water and salts.

Question 11

Describe the salivary glands in the body

Answer 11

These paired structures usually reside in the thorax (adjacent to the foregut).

Question 12

Three main functions of the salivary glands

Answer 12

1. Moisten food
2. Lubricate the mouthpart
3. Contains digestive enzymes

Question 13

Describe the needle like stylet in terms of its structure with the salivary gland.

Answer 13

It possesses two canals, one to ingest food and one to release saliva.

Question 14

What are the two types of saliva?

Answer 14

1. Gel-like (hardens to produce the salivary sheath
2. Water-like (saliva with digestive enzymes)

Question 15

The salivary sheath may stay attached to the feeding site, but in some cases…

Answer 15

It may remain attached to the stylet when feeding ceases being subsequently expelled during grooming

Question 16

In the excretory system what are the long, spaghetti-like structures extending throughout most of the abdominal cavity where they serve as excretory organs, removing nitrogenous wastes (principally ammonium cation NH4+) from the hemolymph.

Answer 16

Malpighian tubes