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Flashcards in Organisation of the Nervous System Deck (26)
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1
Q

What are the two divisions of the nervous system?

A
  1. CNS - the brain and spinal cord

2. PNS - axons, ganglia and supporting cells

2
Q

What are the two types of cells found in neural tissue?

A
1 = neurons or nerve cells which transmit electrical impulses along their cell membranes
2 = neuroglia which are responsible for supporting the neuron, regulating interstitial fluid and bringing nutrients
3
Q

Why do neural cells have no capacity for cell division and what does this mean for the cells?

A

They are highly differentiated and this means they have limited capacity to repair themselves after injury.

4
Q

What on a neuron allos them to communicate with each other?

A

Synapses on the dendrites.

5
Q

What are neuroglia and what are the 4 types?

A

These are non nervous support cells. The four types are, astrocytes, oligodendrocytes, microglia and ependymal cells

6
Q

What are the functions of astrocytes?

A

Maintenance of the blood-brain barrier (separates circulating blood in the brain and extracellular fluid in the CNS).
Contain microfilaments which give strength to the CNS.
Stabilise structure after injury and produce scar tissue.
Direct neural growth during development.
Controlling interstitial environment including neurotransmitters.

7
Q

What is the function of a oligodendrocyte?

A

They wrap together or form myelin to improve the conducting velocity of the axons. The section they wrap around is the axon.

8
Q

What does a microglia cell do?

A

They are immune cells which have a similar function to macrophages but they work in the brain.

9
Q

What does an ependymal cell do?

A

Lines the passageways of the CNS. They are epithelial cells that make branching processes with other glial cells.

10
Q

Where are cell bodies found in the PNS?

A

In the ganglia, supported by satellite cells.

11
Q

How many pairs of cranial severs leave the brain? How many pairs of spinal nerves go to the PNS?

A

12

20

12
Q

What do somatic nerves contain?

A

Motor and sensory fibres

13
Q

All sensory axons whether somatic or autonomic have their cell bodies — the CNS in — where there are — synapses?

All motor ganglia belong to the — nervous system and —- contain synapses.

A

outside, ganglia, no

autonomic, always

14
Q

What is the shape of the cell bodies in the spinal cord? What matter is this? What two sides run together?

A

In a H shape (grey matter). The motor and sensory side which run together.

15
Q

Why does the anterior ramus of the vertebrae contain more axons than the posterior one?

A

The anterior one supplies all the thoracic region but the posterior only supplies sin on the back.

16
Q

What sample can be taken from the vertebrae to look for damage?

A

A sample of the fluid in the spinal cord.

17
Q

What neuron goes in and what neuron leaves the spinal cord? What are the two branches coming off each vertebrae?

A

The sensory neuron comes in and the motor neuron leaves.

There is a posterior branch towards the back and the anterior branch towards the front.

18
Q

What is a dermatome?

A

An area of skin that is mainly supplied by afferent nerve fibres from the dorsal root.

19
Q

What is a nerve plexus? Explain details on this.

A

A nerve plexus is a branching network of intersecting nerves. The anterior rami of all spinal nerve rejoin to form plexuses. These networks occur in the cervical, brachial, lumbar and sacral regions of the vertebrae. Fibres from different anterior roots crisscross and are redistributed so each plexus contains fibres from different nerves.

20
Q

Where do sensory fibres have their ganglia?

A

In the posterior root ganglia of the spinal nerves or in the sensory ganglia of the cranial nerves.

21
Q

Where do the cell bodies of the motor neurons lie?

A

In ganglia outside the CNS.

22
Q

Autonomic motor pathways consist of two neurons in series. Explain this.

How does this differ from the somatic pathway?

A

The first has its cell body in the CNS with the axon extending to the autonomic ganglion where it synapses. From here, the axon from the cell body travels to the effector organ.

The somatic pathway has no synapses.

23
Q

What is the distribution and innervation of the sympathetic nervous system?

A

Distribution: All parts of the body wall and viscera
Function: Innervation of all skin sweat glands, the arrector pili muscles of the hairs, muscular wall of blood vessels

24
Q

What are typical effects that the sympathetic nervous system has on the body?

A

Staring eyes, cold, clammy skin, dry mouth, hair standing on end.

25
Q

What is the distribution and function of the parasympathetic nervous system?

A

Distribution: head and trunk only
Function: localised response used to conserve energy e.g. slowing heart rate

26
Q

What is the length of the preganglionic (CNS) and postganglionic (PNS) for the sympathetic and parasympathetic divisions/

A
Sympathetic = short preganglionic and long postganglionic
Parasympathetic = vice versa

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