4.1 central nervous system

what is the nervous system

communication network and control centre of the body and is made up of the brain, spinal cord and nerves.

what is a short summary of the function of CNS

processes incoming messages and initiates outgoing messages.

how is the brain and spinal cord protected?

bone, meninges, cerebrospinal fluid.

what bones protect the brain and spinal cord

cranium, part of the skull that houses.

spinal cord runs thru vertebral canal, opening in the vertebrae.

what are the meninges

layers of connective tissue forming membranes found inside the bone and covering the surface of the brain and spinal cord.

describe the dura mater

outer layer, tough and fibrous, provides layer of protection on the brain. sticks closely to bones of skull but not much on vertebral canal. contains large blood vessels that break into capillaries in the Pia mater.

describe the arachnoid mater

middle layer that is made of loose mesh fibres, cushions CNS & thin, transparent membrane

describe the Pia mater

inner layer, thin layer of fibrous tissue. adhered to surface of brain and spinal cord, impermeable to fluid, have capillaries that connects to the brain and spinal cord. provides nourishment to the CNS

describe the cerebrospinal fluid

clear, watery fluid

contains few cells and glucose, protein, urea and salts'

located between the middle and inner layer of the meninges

circulates through the cavities of the brain and central spinal cord canal

what are the 3 functions of the CSF

1. transport= CSF formed from blood, circulates around and thru the CNS before re-entering capillaries. takes nutrients to brain and spinal cord, removes waste products

2. protection= acts as a shock absorber

3. support= brain suspended inside cranium and floats in fluid

what is the ventricle?

structure in the brain that contains CSF. Helps transport nutrients and removes wastes

describe the cerebrum

largest part of the brain, consists of outer surface of grey matter known as cerebral cortex and the deep part of the brains grey matter = basal ganglia, also contains white matter

what is grey matter

neurons cell bodies, dendrites, and unmyelinated axons.

what is white matter

myelinated axons

define myelinated

lines neurons to protect and insulate them

aids in quick transmission in electric currents from one nerve cell to the next

what are the 3 types of folds in the cerebrum

fissure= deep downfolds

convolutions=rounded ridges '

sulci= shallow downfalls

what are the 3 functions of the cerebral cortex?

sensory: receive and process nerve impulses from afferent pathway (5 senses)

motor: send impulses to effectors via efferent pathway (movement&speech)

association: interpret info from the sense and make it useful (memory, awareness)

what is the corpus callosum

network of nerve fibres that connect the two cerebral hemispheres and allow communication between the two.

what is the cerebellum responsible for

posture, balance and the coordination of movement

for posture and balance, where does the cerebellum receive its sensory information from?

inner ear

function of hypothalamus

regulation of body temperature, blood pressure, heart rate, food and water intake, patterns of waking and sleeping

function of the medulla oblongata

continuation of the spinal cord, responsible for cardiac (heart rate and force), respiratory (breathing) and the vasomotor centre (blood vessel dilation

function of pons

connects brain to spinal cord and relays messagesunctif

function of midbrain=

processes visual and auditory messages

function of cerebral cortex

thinking, learning, reasoning, memory, conscious awareness

describe the spinal cord

extension of medulla oblongata, enclosed in vertebral canal, canal lined with meninges, space between vertebral canal and spinal cord is filled with fat, connective tissue and blood vessels.

what does the fat, connective tissue and blood vessels help with in the space between spinal cord and vertebral canal?

helps the spinal cord bend when the spine is bent

describe the cross-section of the spinal cord

central core= grey matter

(nerve cell bodies, and unmyelinated nerve fibres. motor and sensory neurons synapse with connector neurons)

outer part= white matter

(ascending and descending tracts of myelinated fibres)

contrast the matter in the brain and spinal cord

brain: outer=grey matter, inner= white matter

spinal cord: outer white matter, inner= grey matter

what are the functions of the spinal cord

carry sensory impulses to the brain, motor impulses away from the brain

processes fast, automatic responses (reflexes)

differentiate between ascending and descending tracts

ascending= sensory axons TO brain

descending= motor axons AWAY from brain