W9: Invertebrate Physiology (Physiology Overview 1) [Dr. Blair]

Question 1

What do you think underpins physiology in insects? (5)

Answer 1

• Body plan.
• Brain.
• Nervous system.
• Circulatory system.
• Extras.

Question 2

Cross-section through the body segment of an insect: What components are there? (7)

Answer 2

• Exoskeleton (chitin).
• Jointed limbs.
• Coelom.
• Gastrointestinal tract.
• Sternum.
• Heart (on dorsal side).
• Nerve chord (on ventral side).

Question 3

Cross-section through an APES student: What components are there? (5)

Answer 3

• “Coelom”.
• Gastrointestinal tract.
• Sternum.
• Nerve chord (on dorsal side).
• Heart (on ventral side).

Question 4

Differences between Cross-section through the body of an insect VS an APES student? (2)

Answer 4

• Heart of an insect is on the dorsal side, while the heart of an APES student is on the ventral side.
• Nerve chord of an insect is on the ventral side, while the nerve chord of an APES student is on the dorsal side.

Question 5

Do insects have more than 1 brain?

Answer 5

No, not exactly as they don’t have the same centralised system as vertebrates.

Question 6

The “Main brain” of an insect is AKA?

Answer 6

Cerebral ganglia.

Question 7

What are the parts of the Cerebral ganglia/ “Main brain”? (3)

Answer 7

• Protocerebrum.
• Deutocerebrum.
• Tritocerebrum.

Question 8

Protocerebrum location?

Answer 8

Anterior part of the insect brain.

Question 9

Protocerebrum function?

Answer 9

To process visual inputs from the compound eyes & simple eyes (ocelli).

Question 10

Deutocerebrum location?

Answer 10

Posterior to the protocerebrum.

Question 11

Deutocerebrum function?

Answer 11

Process sensory information from the antennae, which are important for chemical signals (smell) & mechanical stimuli (touch).

Question 12

Tritocerebrum location?

Answer 12

Posterior region of the insect brain that connects to the head ganglia.

Question 13

Tritocerebrum function?

Answer 13

Coordinates and controls feeding behaviour by integrating sensory information from the mouthparts & regulating associated motor functions.

Question 14

Nervous system attributes? (3)

Answer 14

• Ganglia control different functions (“main brain” controlling different tasks).
• Unlike humans, ganglia are decentralised (literally).
• Ganglia control different parts of the body.

Question 15

Nervous system components from top to bottom? (7)

Answer 15

• “Main brain”/Cerebral ganglia.
• SOG (Subesophageal ganglion).
• Segmental ganglia (thorax).
• Ventral nerve cord.
• Nerves.
• Segmental ganglia (abdomen).
• Caudal ganglia (abdomen).

Question 16

SOG stands for?

Answer 16

Subesophageal Ganglion.

Question 17

Caudal ganglia function?

Answer 17

Control reproduction & excretion.

Question 18

Insect nervous systems summary? (3)

Answer 18

• CNS.
• PNS.
• SNS.

Question 19

Central Nervous System attributes? (3)

Answer 19

• Control center.
• Processes information.
• Information moves from the main brain, nerve cord to ganglia.

Question 20

Peripheral Nervous System attributes? (3)

Answer 20

• Connects the CNS to the body, limbs & organs.
• From the SOG, ganglia to nerves.
• Contains the SGNS.

Question 21

SGNS stands for?

Answer 21

Stomatogastric Nervous System.

Question 22

SGNS function?

Answer 22

Controls gut & digestion.

Question 23

Sympathetic Nervous System (SNS) attributes? (4)

Answer 23

• Controls internal organs.
• Involuntary actions.
• Deals with the heart, tracheae & circulation.
• Visceral Nervous System.

Question 24

Why would insects want a “decentralised brain” system? (3)

Answer 24

• Makes it efficient at processing sensory information & rapid control of movement.
• Enables insects to perform complex behaviours such as flying, reproduction & feeding.
• Allows functionality, even if parts of the nervous system are damaged such as in the case of lost limbs.

Question 25

Loss of limbs attributes? (3)

Answer 25

• Segmental ganglia allows for “autonomous” control.
• Other limbs operate as “normal’.
• No incapacitation.

Question 26

Do insects feel pain?

Answer 26

It’s complicated, but read Crump et al. (2023) paper to come to an informed conclusion.

Question 27

Based on the Crump et al. (2023) paper, Do insects feel pain?

Answer 27

Yes, as some insects felt pain such as flies, cockroaches and bees. Therefore, whether an insect feels pain is species-dependent.

Question 28

Circulatory system of insects attributes? (2)

Answer 28

• Made up of the heart & haemocoel.
• Haemocoel contains the haemolymph.

Question 29

Heart of insects attributes? (3)

Answer 29

• Elongated heart.
• Is a dorsal “vessel”.
• Circulates haemolymph.

Question 30

Haemocoel attributes? (20

Answer 30

• Open cavity.
• Contains haemolymph.

Question 31

Haemolymph attributes? (4)

Answer 31

• Equivalent to “blood” in mammals.
• 90% Water: Plasma.
• Transports nutrients to cells, removes waste & distributes hormones throughout an insect’s body.
• Moves from the butt (bottom) to the head of an insect.

Question 32

Super summary? (3)

Answer 32

• The Brain (cerebral ganglia, decentralised sections).
• Nervous system (CNS/PNS/SNS, perform complex behaviours).
• Circulation (heart, hemolymph, haemocoel, no O2 delivery).