EAC Nervous System Flashcards
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
components of a Neuron
Dendrites Nucleus Myelin sheath Schwann cells Nodes of Ranvier Axons
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
components of the brain
Meninges Cerebrum Cerebellum Brain stem Spinal cord
functions of:
Meninges
have 3 main functions
Protect the brain and cord
To absorb CSF
To maintain the brains position within the cranial vault
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
functions of:
Cerebellum
The cerebellum is underneath the posterior portion of the cerebrum
Controls the maintenance of balance, muscle co-ordination and muscle tone
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)
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
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
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)
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
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
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
define:
Paraplegia
Paralysis of lower limbs, which may involve bladder and rectum
