Nervous system

Question 1

State the three main components of the nervous system.

Answer 1

Sensory neuron, interneuron, motor neuron

Question 2

Outline the main roles of the nervous system.

Answer 2

Monitor the internal and external environment, processing the information from this environment, and direct behaviour and body processes.

Question 3

Outline the main roles of neurons.

Answer 3

Overall role is they support neuronal function,
maintaining the local extracellular environment.

But, they also:
1. Local concentrations of neurotransmitters
2. Supply nutrients
3. Support / guide neuronal development
4. Stabilise neuronal networks
5. ‘Improve’ communication speeds
6. Provide immunological defence

Question 4

State the 2 types of devisions of the nervous system

Answer 4

Anatomical and functional.

Question 5

Outline the 5 meninges from closest to the skull bone to the cortex.

Answer 5

Cranial dura mater
Periosteal layer
Meningeal layer
Arachnoid mater
Pia mater

Question 6

What is unique about the cerebellum?

Answer 6

It holds about 10% of the total brain mass and carries 50% of neurons across the whole brain.

Question 7

Where is cerebrospinal fluid produced and where does it flow?

Answer 7

It is produced in the red middle section of the choroid plexus, and flows through the 4 brain ventricles and down the central canal of the spinal cord.

Question 8

What are the roles of cerebrospinal fluid?

Answer 8

1. Protective medium for brain ‘floatation’
2. Protective cushioning – trauma
3. Nutritive – glucose
4. Removal of metabolites – urea, lactate
5. Provides stable ionic environment

Question 9

What is the difference between the gyri and sulci of the brain?

Answer 9

Gyri are the ridges of the brain and the sulci are the deeper folds to fit all of the millions of neurons in.

Question 10

What are the main gyri and sulci of the brain and where are they located?

Answer 10

There is the pre and post central gyrus which are at the primary sensory cortex at the frontal (pre) and parietal (post) lobes.

The lateral sulcus is between the temporal and parietal lobes, and the central sulcus is between the frontal and parietal lobes.

Question 11

Describe the grey and white matter of the brain.

Answer 11

The grey matter is where neurons, glial cells and blood vessles lie. The white matter is where the fibre tracts, sensory and motor pathways flow through and connects different areas of the brain together.

Question 12

Outline the anatomical divisions of the nervous system.

Answer 12

There is the central nervous system which is the brain and spinal cord, and the peripheral nervous system which is to and from the cranial nerves and spinal nerves. Ganglia such as the dorsal root ganglia lie within the peripheral nervous system, hold neuronal cell bodies and help with spinal tracts/pathways.

Question 13

Outline the functional divisions of the nervous system.

Answer 13

There is the somatic division which is voluntary and controls skeletal muscles, and there is the autonomic division, which is involuntary and controls smooth and cardiac muscle, and organs such as the glands.

Question 14

Outline the two functional divisions of the autonomic nervous system.

Answer 14

Sympathetic (fight or flight)
Parasympathetic (rest and digest)

Question 15

Describe the main lobes of the brain.

Answer 15

Frontal lobe - planning, emotion, behaviour, motor function
Temporal lobe - hearing, language, memory
Parietal lobe - touch, pain, temperature
Occipital lobe - vision

Don’t forget the cerebellum - balance, coordination

Question 16

Where is the insula and what does it do?

Answer 16

It is located deeper in the brain, underneath the temporal lobe. Main roles include:

• Conscious awareness
• Gustation
• Cognitive emotional processing
• Audio-visual integration
• Interoception (autonomic sensory monitoring /regulation)
• Homeostatic error detection

Question 17

Outline some specific functional areas of the brain.

Answer 17

Motor cortex - control of skeletal muscle, motor planning/programmes
Broca’s area - motor control of speech (speech and motor planning), language output area
Auditory cortex - pitch, loudness, location of sound, auditory memory and sound recognition
Sensory cortex - input from skin/proprioceptors and spatial discrimination
Visual cortex - mapping visual input and visual recognition
Wernicke’s area - language, reading/listening, recognition of words and make sense/meaning of words

Question 18

Name the order of areas of the brain of the language loop model.

Answer 18

Visual cortex (read words), Wernicke’s area (context of words), Broca’s area (prepare motor patterns to read out loud), motor cortex (read out loud)

Question 19

Describe the homunculi:

Answer 19

There is the sensory homunculus in the post-central gyrus of the primary somatosensory cortex, which detects where in the body the sensory nerve ending has sent signals from.

There is the motor homunculus in the pre-central gyrus in the primary motor cortex, which determines where in the body the motor output needs to be.

The size of the body feature on a visual map determines the number of nerve cells needed to control the information of that body part.

Question 20

Describe the structure and function of the brain stem.

Answer 20

Consists of medulla, pons, midbrain and reticular formation it contains ascending and descending nerve tracts and is the origin of cranial nerves.

Functions include:
- Filtering
- Control of sleep and consciousness (reticular activating system)
- Modulation of pain
- Regulation of cardiovascular and respiratory systems
- Somatic motor control
- Gaze centres

Question 21

Describe the functions of the cerebellum.

Answer 21

• Control of balance
• Influences posture and muscle tone
• Coordination of movement
• “Motor learning” – muscle memory (knitting, - driving)
• Acts like a comparison system (pre motor cortical areas)