Lecture 22 - Basic Anatomy Of The Nervous System

Question 1

Why do we need a nervous system?

Answer 1

Diffusion of secondary messengers is not fast enough in large organisms. Therefore they have a Nervous system to coordinate their actions

Question 2

What are the 3 basic steps that nervous system follows in responding to the environment?

Answer 2

Receptors detect sensory input/stimulus
This information is processed by the Coordination centres
Then a motor output is produced by the effectors

Question 3

The Nervous system can be split into 2 systems. What are these systems?

Answer 3

CNS
PNS

Question 4

What is the CNS composed of?

Answer 4

Brain
Spinal cord

Question 5

What is the CNSs ability to regenerate after damage like?

Answer 5

Poor

Question 6

What is the PNS?

Answer 6

Everything that is not the brain and spinal cord

Question 7

What are the 2 systems that the PNS can be divided into?

Answer 7

Somatic Nervous system
Autonomic nervous system

Question 8

What is the function of the Somatic Nervous system within the PNS?

Answer 8

Collects information we are conscious of
They are the nerves that cause voluntary actions

Question 9

What is the Autonomic Nervous system responsible for within the PNS?

Answer 9

Responsible for doing the stuff we are not conscious of

Question 10

What are the 3 parts which the Autonomic Nervous system can be divided into?

Answer 10

Sympathetic
Parasympathetic
Enteric

Question 11

What is the function of the sympathetic nervous system? Does it have a wide or targeted affect?

Answer 11

The fight or flight responses
Has more general affect on the wider body

Question 12

What is the neurotransmitter used in the sympathetic nervous system?

Answer 12

Noradrenaline

Question 13

What is the function of the Parasympathetic nervous system? Does it have a wide or targeted affect?

Answer 13

The rest and digest responses
It is targeted to an end organ to have a localised action
Usually affects glands

Question 14

What is the function of the Autonomic Enteric nervous system?

Answer 14

The intrinsic nervous system of the GI tract
It’s is quite primitive
It’s how GI bacteria communicate with the brain

Question 15

What is a Ganglion?

Answer 15

A collection of neurone cell bodies (perikaryons)outside of the brain

Question 16

What is the function of the Dorsal root?

Answer 16

Connects nerves to the back/anterior of the spinal cord

Question 17

What is the function of the Ventral root?

Answer 17

Connects nerves to the front/anterior of the spinal cord

Question 18

Describe the structure of gray matter in the spinal cord

Answer 18

Butterfly shaped
Contains neurones (unmyelinated, dendrites and blood vessels)

Question 19

Describe the structure of the white matter in the spinal cord

Answer 19

Peripheral
Contains mainly myelinated axons (myelin is lipid so is white)
Lots of Oligodendrocytes

Question 20

How many segments is the spinal cord split up into?

Answer 20

31 segments
So 31 pairs of spinal nerves

Question 21

What does the map of the Human Dermatome show?

Answer 21

Shows which pair of 31 pairs of spinal nerves supply areas of the skin

Question 22

What are the 5 types of spinal nerves?

Answer 22

Cervical nerves (8)
Thoracic nerves (12)
Lumbar nerves (5)
Sacral (5)
Coccygeal (1)

Question 23

Look in notability at the for the Diagram for Basic Spinal cord wiring.
Try and describe the way the sensory neurone travels and how the motor neuron travels
What would indicated dorsal root damage?
What would indicate ventral root damage?
What would indicate spinal nerve damage?

Answer 23

Dorsal root damage - only sensory is affected
Ventral root damage - motor and autonomic fibres affected
Spinal nerve damage- both sensory and motor autonomic affected since the spinal nerve is made by the joining of the dorsal root and ventral root

Question 24

How many neurones are chained in the Autonomic Nervous system?

Answer 24

2 are chained between the CNS and target organ

Question 25

Where is the synapse between the 2 chained neurones in the Autonomic nervous system located?

Answer 25

In an autonomic ganglion

Question 26

Where is the preganglionic neurone perikaryon located?

Answer 26

CNS

Question 27

Where is the Postganglionic Neurone Perikaryon located?

Answer 27

In an autonomic ganglion

Question 28

Describe the length of the Preganglionic neurones axon and the postganglionic neurone in the Sympathetic Autonomic Nervous system

Answer 28

SHORT Preganglionic LONG Postganglionic

Question 29

Describe the length of the Preganglionic neurones axon and the postganglionic neurone in the Parasympathetic Autonomic Nervous system

Answer 29

LONG Preganglionic axon SHORT Postganglionic axon

Question 30

In the Autonomic nervous system (sympathetic and parasympathetic) which neurones are myelinated? Preganglionic or Postganglionic?

Answer 30

Preganglionics are myelinated Postganglionic are non-myelinated

Question 31

Where are Autonomic Sympathetic Preganglionic neurone Perikaryons found in the CNS?

Answer 31

Found in the lateral horn of the spinal cord from the T1-L2 segments

Question 32

What is Thoracolumbar outflow?

Answer 32

The sympathetic nerves which span from through all 12 of the thoracic segments of the spinal cord and the first 2 lumbar segment of the spinal cord

Question 33

What are and where is the lateral horn found?

Answer 33

Extra horns which are only found in the sympathetic portions of the Autonomic nervous system It is where the sympathetic Preganglionic neurones reside

Question 34

Where are the Autonomic Parasympathetic perikaryons found in the CNS?

Answer 34

2 separate regions Along whole length of Brainstem Sacral spinal cord segments S2, S3 and S4

Question 35

What is Craniosacral outflow?

Answer 35

The parasympathetic nerves which span through all of the brainstem and the 2nd, 3rd and 4th sacral cord segements

Question 36

How is the sympathetic nervous system layed out?

Answer 36

Short Preganglionic neurones from the T1 segment to the L2 segment lead to Sympathetic ganglia SYmpathetic ganglia arranged into 2 chains of gangli called Sympathetic chains

Question 37

How is the parasympathetic system laid out?

Answer 37

The postganglionic neurones are located in the wall of the target regions This means the preganglionic neurone axons are long and the postganglionic neurone axons are short

Question 38

How do sympathetics communicate with spinal nerves generally?

Answer 38

Through the white and then gray ramus communicans

Question 39

Describe how the impulse travels from the spinal cord to the rest of the body if its using the SYMPATHETIC NERVOUS SYSTEM

Answer 39

Starts in ventral horn, travels along ventral root through preganglionic neurone This travels across a WHITE ramus communicans to a Ganglion in the sympathetic chain Here it synapses to a postganglionic neurone The postganglionic neuron passes across the GRAY ramus communicans back to the spinal nerve where it can then travel to its destination in the body

Question 40

Where do Sympathetic preganglionics exist?

Answer 40

In only the T1-L2 segments of the cord

Question 41

How do sympathetics communicate with the rest of the body?

Answer 41

Can synapse at the level of entry if target is between the T1-L2 segments Impulse can ascend the sympathetic chain then synapse to supply head and neck(postganglionic as get to targets along blood vessel walls) Impulse can descend the chain then synapse to supply lower limbs

Question 42

What is the importance of the sympathetic chain?

Answer 42

It facilitates sympathetic impulse transmission outside of the thoracic spine

Question 43

Where do Parasympathetic preganglionic neurones normally synapse?

Answer 43

In ganglia that sit close to their target organ/region

Question 44

What is the major source of parasympathetic preganglionic input to the thoracic and abdominal viscera?

Answer 44

The vagus nerve (Tenth cranial nerve)

Question 45

What are the 4 specialised parasympathetic ganglia?

Answer 45

Ciliary ganglion Pterygopalatin ganglion Submandibular ganglion Optic ganglion

Question 46

Where does the ciliary ganglion receive parasympathetic Preganglionics from? Where does the ciliary ganglion distribute the parasympathetic postganglionics to?

Answer 46

Receives from Oculomotor nerve Distributes to the Eye

Question 47

Where does the pterygopalatine ganglion receive parasympathetic Preganglionics from? Where does the pterygopalatine ganglion distribute the parasympathetic postganglionics to?

Answer 47

Receives from Facial nerve Distributes to Lacrimal Gland

Question 48

Where does the submandibular ganglion receive parasympathetic Preganglionics from? Where does the submandibular ganglion distribute the parasympathetic postganglionics to?

Answer 48

Receives from the Facial Nerve Distributes to Submandibular and Sublingual salivary glands

Question 49

Where does the Otic ganglion receive parasympathetic Preganglionics from? Where does the Otic ganglion distribute the parasympathetic postganglionics to?

Answer 49

Receives from the Glossopharyngeal nerve Distributes to the Parotid gland