Lecture 1 + 2 - Neuroanatomy

Question 1

On the spinal cord, where are the sensory nerve roots?

Answer 1

Dorsal column

Question 2

On the spinal cord, where are the motor nerve roots?

Answer 2

Ventral column

Question 3

What are the four levels of nerve roots in the spinal cord?

Answer 3

Cervical, thoracic, lumbar and sacral.

Question 4

Which area of the spinal cord is innervated by the sympathetic NS???

Answer 4

Thoracic and Lumbar. T1 to L3.

Ach > NA. (releases NA to organs)

Question 5

Which areal of the spinal cord is innervated by parasympathetic NS?

Answer 5

Sacral S2 TO S4

Ach > Ach (releases ACh to organs)

Question 6

What are the four parts of the human CNS during embryonic development?

Answer 6

PMRS.

Prosecephalon - FOREBRAIN - has telecephalon (cerebral hemospheres) and diencephalon (thalamus, hypothalamus, epithalamus)

Mesencephalon - cerebrain peduncles, midbrain tectum, midbrain tegmentum.

Rhombencephalon - Pons, cerebellum, Medulla.

Spinal Cord

Question 7

What are the layers of the neocortex?

Answer 7

counting from the surface inward:

1. Molecular Layer - dendrites and axons from other layers.
2. Small Pyramidal Layer - cortical-cortical connections
3. Medium Pyramidal Layer - cortical-cortical connections
4. Granular Layer - receives inputs from thalamus
5. Large pyramidal layer - sends outputs to subcortical structures
6. Polymorphic Layer - sends outputs to thalamus

MSMGLP - Mum smokes marijuana, grandma licks penis.

Relative thickness of cell layers varies according to the main func of that area of brain.

Question 8

Describe broddmann’s cytoarchitectonic areas.

Answer 8

OMG

Question 9

Which brodmanns area reprsents the fovea of the visual field

Answer 9

A 17

Question 10

What arises from dysfunction of association areas?

Answer 10

AGNOSIA

Question 11

Describe the monosynaptic stretch reflex.

Answer 11

muscle spindles (specialised receptors) > transmitted to sensory neurons > conveyed via dorsal roots > forms multiple synapses, some to LMNs in anterior horn causing muscle contraction.

The sensory neuron also synapses onto inhibitory or excitatory interneurons in the spinal cord, which then make synapses onto the LMNs.

Question 12

What are the two major somatosensory pathways?

Answer 12

• posterior column pathways

- anterolateral pathways.

Question 13

Describe the posterior column pathway

Answer 13

This controls proprioception, vibration, and fine, discriminative touch.

1. Dorsal root in spinal cord
2. Ipsilateral dorsal column nulciei in medulla
3. synapse onto secondary sensory neurons and cross over.
4. synapse in thalamus
5. primary somatosensory cortex.

Question 14

Describe the anterolateral pathway

Answer 14

detects pain, temperature and crude touch.

1. dorsal root in spinal cord
2. synapse in gray matter of spinal cord
3. cross over in spinal cod and ascend in anterolateral white matter
4. synapse in thalamus
5. primary somatosensory cortex.

Question 15

What does the thalamus do?

Answer 15

• relay centre
• nearly all pathways that project to cortex come from synapsing in the thalamus
• gray matter structure

Question 16

What does the reticular formation do

Answer 16

sends circuits out to thalamus, then to cortex to regulate consciousness.

Question 17

What are luria’s three funcitonal blocks?

Answer 17

Block 1 - brainstem, RAS - regulates the energy level and tone of cortex.

Block 2 - three posterior cortical lobes - analyse, code and store info

Block 3 - frontal lobe - formation of intentions, and direction of cognition and motor activity.

Question 18

What are the types of association cortices?

Answer 18

• unimodal - only processes a single sensory or motor modality.
• heteromodal - integrates functions from multiple sensory and motor modalities.

Question 19

What does a dysfunction in sensory secondary association areas do?

Answer 19

agnosia

Question 20

What does a dysfunction in motor secondary association area cause

Answer 20

apraxia

Question 21

What projects to the thalamus, and then where doe the thalamus project to?

Answer 21

limbic system, RAS, cerebellum, basal ganglia, and all somatosensory inputs (Except olfactory) project to the thalamus

the thalamus then projects to basically every area of the cortex

the demands of the body are subserved by the hypothalamus

Question 22

What do paralimbic areas do?

Answer 22

paralimbic areas including the temporal pole, the orbitofrontal cortex, the insula, the parahippocampal gyrus and the cingulum. These areas are responsible for the modulation of drive and control of the homeostatic urges as they impinge on the environmental demands, including emotion and memory,

Question 23

What do the unimodal association areas do?

Answer 23

hese areas surround the primary reception and transduction areas and are responsible for attachment of meaning to the patterns of sensory activation: perception as opposed to sensation.

Question 24

What do the heteromodal association areas do?

Answer 24

These areas are equivalent to Luria’s zones of overlapping and are responsible for the integration of material from each of the sensory systems, and developing motor programs for responding to the implications of the sensory input.

Question 25

What do the limbic areas do?

Answer 25

These areas are in closest association with the centres in the brain stem and hypothalamus which control homeostasis or maintenance of the internal state of the body