central nervous system

what does the central nervous system consist of?

brain and

what are the different parts of the brain?

cerebrum, corpus callosum, cerebellum, hypothalamus, medulla oblongata

what is the biggest part if the brain?

the cerebrum

what is the cerebral cortex?

is the 2-4mm outer surface of the cerebrum

is the cerebral cortex grey or white matter?

grey

what is the grey matter made up of?

the grey matter is made up off neuron cell bodies, dendrites, and unmyelianted axons

what is the white matter made up of?

myelinated axons, the fatty nature of the myelin gives the white matter its colour and texture

what is the basal ganglia?

is deep inside the cerebrum and is additional grey matter

why is the surface of the cerebral cortex folded?

to increase the surface area, the cortex contains 70% of all neurons in the central nervous system

what are the rounded ridges on the cerebral cortex called?

are called convolutions or gyri (singular gyrus)

what are the downfolds of the cerebral cortex called?

suli or singlular suclus

what are the very deep downfolds called?

fissures

what is the deepest fissure called in the brain?

the longitudinal fissure

what is the function of the longitudinal fissure?

is to seperate the cerebrum into two hemispheres

what are the two hemispheres called in the brain

left and right

what is the corpus callosum?

is the area of white matter consisting of a large bundle of transverse fibres that joins the two hemispheres at the base of the longitudinal fissures

what are transverse fibres?

axons that connect the two hemispheres of the brain

are the patterns of folding of the cerebral cortex the same in every person?

no it varies from person to person, however certain fissures and sculi are fairly consistent and are used to further subdivide each cerebral hemisphere into four lobes.

what are the four lobes of the each cerebral hemisphere?

frontal, temporal, occipital and parietal lobes (sometimes there is a fifth insula)

what is the cerebral white matter made of?

myelinated axons, and bundles of nerve fibres in the central nervous system called tracts.

what are the different types of tracts in the white matter of the central nervous system?

association, commissural, and projection fibres

where are the tracts of the association fibres?

tracts connect areas of cortex within the same hemispheres

where are the commissural fibre tracts?

tracts between the left and right hemispheres

where are the projection fibre tracts?

tracts that connect cortex to other parts of the brain or the spinal cord

in the central nervous system, what are bundles of nerve fibres called?

tracts

the basal ganglia consist of what type of cel bodies?

cell bodies associated with control of skeletal muscles.

what is the function of basal ganglia?

to play a role in initiating desired movements and inhibiting unwanted movements

what is the function of cerebral cortex?

mental activities such as thinking, reasoning, learning, memory, intelligence, and sense of responsibility. It is also concerned with sensory perception, the initiation and control of voluntary muscle contraction

where are nearly all impulses from sense organs carried to?

the cerebral cortex, which then has all the relevant information about the environment and can initiate responses accordingly

the cerebral cortex can be divided into what three functional areas?

sensory, motor and association areas.

what is the function of there sensory areas of the cerebral cortex?

interpret impulses from receptors

what is the function of the motor areas of the cerebral cortex?

control muscular movements

what is the function of the association area of the cerebral cortex?

this area is concerned with intellectual and emotional processes

what area of the cerebrum is concerned with memory?

the association areas of the cerebral cortex.

How are memories stored?

memories are not stored in individual memory cells in the brain; they are pathways of nerve cells.

what happens when a new memory is stored?

new links are made via circuits. new links are either made between neurons or existing links are modified.

how is the cerebrum studied?

looking at brainwaves- electroencephalogram, changes to blood flow, effects of damage and disease, experimentation of other mammals

are the type hemispheres of the cerebrum identical?

nah

what hemisphere is language ability mainly controlled from?

left

what hemisphere is music and art mainly controllled from?

right

where is the corpus callosum sitting in the brain?

lies underneath the cerebrum at the base of the longitudinal fissure

what is the corpus callosum made up of?

wide band of nerve fibres

what is the function of the corpus callosum?

allows the two hemispheres of cerebrum to communicate with each other due to nerve fibres in corpus callosum that cross from one cerebral hemisphere to the other.

where is the cerebellum located?

under the rear part of the cerebrum

what is the second largest part of the brain?

cerebellum

what is the structure of the cerebellum?

its surface is highly folded into a series of parallel ridges. the outer folded part is grey matter. the inside is white matter that branches to al parts of the cerebellum

what is the function of the cerebellum?

it exercises control over posture, balance, and fine coordination of voluntary muscle movement. it also smooths and coordinates movement (all of these functions of cerebellum takes place below conscious control)

How does the cerebellum function?

it receives input from the inner ear about posture and balance, and receives information from the stretch receptors in skeletal muscles for information about the length of muscles.

can we liv without a cerebellum?

yes, because impulses do not originate in the cerebellum and so without it we could still move- however moments would be spasmodic, jerky and uncontrolled(e.g playing instruments would be impossible)

where is the hypothalamus located?

deep in the middle of the brain

what is the function of the hypothalamus?

maintaining a constant internal environment (homeostasis). Autonomic nervous system which includes the regulation of heart rate, blood pressure, secretion of digestive juices, movements of the alimentary canal, diameter and pupil of the eye. Also regulates body temperature, food and water intake, patterns of waking and sleeping, contraction of urinary bladder, emotional responses such as anger, aggression, pleasure, contentment, and the secretion of hormones and coordination of parts of the endocrine system acting through the pituitary gland which regulates metabolism, growth, reproduction and response to stress.

what is the structure of medulla oblongata?

is a continuation of the spinal cord and is approx 3 cm long which extends fro juts above the point where spinal cord enters the skull. Many fibres simply pass through the medulla oblongata going to and from the other parts of the brain.

what are the centres in the medulla oblongata?

cardiac, respiratory, and vasomotor centres

what is the function of the cardiac center?

it regulates the force and rate of the heartbeat

what is the function of the respiratory centres?

to control the rate and depth of breathing

what is the function go vasomotor centre?

it regulates the diameter of blood vessels

what are the functions of the other centres of the medulla oblongata

reflexes in swallowing, sneezing, coughing and vomiting.

What higher centre of the brain is the medulla oblongta influenced by

hypothalamus, work close together to maintain homeostasis

what is the structure of the spinal cord?

extends from the foramen magnum (large opening at the base of the skull) to the second lumbar vertebra (approx waist level)

how is the spinal cord heavily protected?

is enclosed in vertebral canal and inside ring of bone with 3 meningeal layers. the outermost meningeal layer is not joined to the bone as it is joined to the skull. instead space containing fat, connective tissue and blood vessels serves as padding around spinal cord which allows the cord to be bent.

what is the structure inside the spinal cord?

grey matter in the centre (in approx H shape) and white matter in the inside. in the middle of the H is a small space called the central canal

what is the central canal?

canal that runs the length of the spinal cord and contains cerebrospinal fluid

myelinated fibres of white matter arranged in bundles of what tracts

ascending and decending tracts

what are the functions of the decending tracts int he spinal cord?

they contain motor axons that conduct impulses downwards away from the brain.

what are the functions of the ascending tracts?

sensory axons that carry impulses upwards towards the brain

what is anther function of the spinal cord?

to integrate certain fast, automatic responses/ reflexes