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Flashcards in EAC Nervous System Deck (19):
1

3 main functions of the Nervous System

Receive stimuli from outside and inside the body, analyse them and coordinate an appropriate response

Convey impulses from the brain which may stimulate or depress activity in muscular, glandular and other tissues

Integrate the many different functions carried out by individual organs, tissues and cells

2

components of a Neuron

Dendrites
Nucleus
Myelin sheath
Schwann cells
Nodes of Ranvier
Axons

3

two main divisions of the Nervous System

The central nervous system: brain and spinal cord

The peripheral nervous system: 12 pairs of cranial nerves, 31 pairs of spinal nerves and the autonomic nervous system

4

components of the brain

Meninges
Cerebrum
Cerebellum
Brain stem
Spinal cord

5

functions of:
Meninges

have 3 main functions

Protect the brain and cord

To absorb CSF

To maintain the brains position within the cranial vault

6

functions of:
Cerebrum

consists of 2 large hemispheres. left controls right side body and visa versa.

Motor areas which initiate the contraction of voluntary muscles

Sensory areas which receive impulses from the skin, muscles, bones and joints

Special sense centres which deal with sight, hearing, smell, taste and touch

Centres of 'high mental powers' which allow for consciousness, memory, intelligence, reasoning etc.

The centres (thalamus and hypothalamus) which control the autonomic nervous system and are deep inside the base of the cerebrum

7

functions of:
Cerebellum

The cerebellum is underneath the posterior portion of the cerebrum

Controls the maintenance of balance, muscle co-ordination and muscle tone

8

functions of:
Brain Stem

Mid Brain: relay station connecting upper brain and lower brain and spinal cord.
Contains important reflex centres affecting the eyes, head and neck in response to visual and other stimuli.

Pons Varolli: links various parts of the brain to one another. Joins the cerebrum above, through the Mid Brain, to the Medulla and Cerebellum below

Medulla Oblongata: Link between the brain and the spinal cord, joining the Pons Varolli above to the cord below. components are:
Motor fibres which cross over (L controls R etc.)
Vital centres (respiratory, cardiac and vaso-motor)
Reflex centres (control food and air passages - cough, sneeze, vomit, swallow)

9

functions of:
Spinal Cord

Its the large trunk of nervous tissue extending from the brain stem to L2.

Link the brain and nerves supplying the outer parts of the trunk and the limb

Act as the centre of reflex action

10

functions of:
Cerebrospinal Fluid

Produced and contained by the 4 cavities/ventricles which circulates around the brain and spinal cord.

crystal clear fluid

functions are:
Lubricate the brain and spinal cord, preventing friction during movement
Support the brain
Act as a shock absorber
Nourish and cleanse by washing away waste and toxic substances

11

function of:
Autonomic Nervous System

supplies nerves to internal organs and blood vessels.

So called because these organs are self controlled

Controls involuntary movements of organs and glands of the body and involuntary muscles (pupil of the eye, heart rate, breathing and peristalsis)

formed of:
Sympathetic Nerves (quickens heart, circulatory and respiratory systems but inhibits peristalsis)
Parasympathetic Nerves (stimulate digestion, slow heart)

12

function of:
Central Nervous System

Spinal cord:
Lies in the vertebral column
Extends from the Medulla Oblongata to L2
approx. 45cm long in adults
31 pairs of spinal nerves
Links the brain and nerves supplying the outer parts of the trunks and limbs
Acts as a centre for reflex action

Peripheral Nerves:
Sensory - convey info about external world
Motor

13

Reflex actions

are very rapid responses to certain stimuli that allow the body to protect itself

occur mainly in the spinal cord and brain stem

14

medical conditions associated with Spinal Cord Injury

Paraplegia
Tetraplegia or quadriplegia
Hemiplegia
Monoplegia
Meningitis

most common and significant insult to the brain or spinal cord is hypoxia. USE airway management and O2 if required

15

define:
Paraplegia

Paralysis of lower limbs, which may involve bladder and rectum

16

define:
Tetraplegia/Quadriplegia

Paralysis of all four limbs

17

define:
Hemiplegia

Complete or partial paralysis of one side of the body

18

define:
Monoplegia

Paralysis of one limb

19

define:
Meningitis

Inflammation of the meninges