MA - Neuroanatomy I

Question 1

What is included in the PNS? (3)

Answer 1

• Cranial Nerves
• Spinal Nerves
• Ganglia (Dorsal root ganglia and autonomic ganglia)

Question 2

What are 2 features of the CNS?

Answer 2

• Brain and spinal cord
• Control centre for information processing

Question 3

What are the 3 features of Neurons?

Answer 3

1. Recieve stimuli
2. Transmit nerve impulses or action potentials
3. Activate muscles

Question 4

What are the actions of Dendrites, Cell bodies and Axons?

Answer 4

Dendrites- collect electrical signals and carry to cell bodies
Cell body- integrates signals and generates action potential
Axon- transmits signals over long distances from the cell body to axon terminals

Question 5

What is an example of a multicellular organism without a nervous system?

Answer 5

Sea sponges

Question 6

What are invertebrate nervous systems specialised for? (2)

Answer 6

• Stimulus/ response, receptor/effector
• Reflexes, conditioned responses

Question 7

What are features of Nerve nets? (6)

Answer 7

• The simplest form of the nervous system found in some invertebrates
• Individual nerve cells exist in a net-like formation scattered in layers of the body wall
• Neurons exist in loose networks to allow for contraction and expansion of the body cavity
• Lack distinct central or peripheral regions
• Have no associate activities (just reflexes)
• Nerve signals can travel in both directions

Question 8

How do species display centralisation of the nervous system? (2)

Answer 8

• A ring of neurons is located in the centre with bundles of neurons (radial nerves)
• Radial nerves form nerve nets permitting coordinated movement

Question 9

How is the primitive brain formed?

Answer 9

In animals with bilatteral symmetry, there is a clustering of neurons into ganglia near the head of the animal

Question 10

Can the CNS or PNS act autonomously?

Answer 10

Only the PNS can

Question 11

How is action potential propagation overcome in invertebrates that lack myelin?

Answer 11

By increasing the diameter of axons

Question 12

What do vertebrate nervous systems contain? (3)

Answer 12

• Sophisticated sensory mechanisms
• Clear differentiation of CNS and PNS as well as sensory and motor nerves
• Elaboration of brain structure

Question 13

What are the 3 types of brain?

Answer 13

• Forebrain (cerebrum, optic structures, olfactory lobe)
• Midbrain
• Hindbrain (Brainstem, pons, medulla, cerebellum)

Question 14

What are sulci and gyri?

Answer 14

Sulci- infoldings of the cerebral cortex
Gyri- ridges of the infolded cerebral cortex