Lecture 13: Mollusca Flashcards
1
Q
The radula
A
rasping organ that reduces prey to small fragments passed into pharynx
2
Q
The foot
A
attached animal to substrate
3
Q
The mantle
A
secretes a shell to protect mollusc
4
Q
Three layers of shell
A
- Periostracum (outermost)
- Prismatic (middle)
- Nacreous (innermost)
5
Q
The shell
A
elongated cone that spirals into a central axis so it is easier to carry
6
Q
The nervous system
A
- consists of ganglia and nerve cords
cerebral ganglia: located above oesophagus
pedal ganglia: beneath oesophagus
pleural ganglia: behind and below ganglia
7
Q
Glial Cells
A
- electrical insulation of nerve cells
- provide nutrients, O2, maintain extracellular environment, fight infections etc.
8
Q
Resting
A
- negative inside neuron
- K and Na closed
9
Q
Depolarization
A
- Na channels open
10
Q
Hyperpolarization
A
- Na channels close, K channels open
11
Q
Torsion
A
- twisting of visceral mass unit until mantle cavity, gills, anus, gonopore and nephridiopore are anterior above the head
12
Q
Metamorphosis of Mollusc
A
- veiger lives for a few hours to a few weeks in plankton
- sinks to bottom and begins to crawl or attach
13
Q
Conus
A
- modification of radula, used for protection (launch harpoon to poison prey)
14
Q
Naudibranches
A
- don’t go through torsion
- very poisonous
15
Q
Pterotrachea
A
- have modified foot into ventral swimming fin
