INTRODUCTION

Perhaps more than any other clients we encounter clients who are comatose or confused need to care for in a holistic manner. All aspects of physiologic and psychological function to need to addressed. Even if clients cannot interact with their surroundings the nurse must care for them in respectful and dignified manner. The brain requires a constant supply of oxygenated blood and glucose to function. Interruption of this supply will cause loss of consciousness within a few seconds and permanent brain damage in minutes.

Meaning of consciousness

It is a state of that has three important aspects-Wakefulness;

Wakefulness is the ability to maintain an awake state or to be easily aroused from sleep

2) Awareness of self;It means the client can identify his or her present location.3) Awareness of Environment and time;It indicates that client knows the location, time, date

Review of anatomy:

The brain constitutes about one fiftieth of the body weight and lied within the cranial cavity. The parts are

Cerebrum Mid brain Pons Medulla oblongata Cerebellum

1.Cerebrum:

This is the largest part of the brain and occupies the anterior and middle cranial fossae.it divided by a deep cleft, the longitudinal cerebral fissure, into right and left cerebral hemispheres, each containing one of the lateral ventricles. Deep within the

brain hemisphere are connected by a mass of white matter called corpus callosum.The superficial part of the cerebrum is composed of nerve cells bodies or grey matter, forming the cerebral cortex, and the deeper layer consist of nerve fibers or white matter.

Functions

o Mental activities involved in memory, intelligence, thinking ,reasoningo Sensory perception including the perception of pain, temperature, touch,

hearing, taste, and smello Initiation and control of skeletal muscle contraction(voluntary)

2. Diencephalon:Deep within the cerebral hemisphere there are groups of cell bodies called nuclei (previously called ganglia) which act as relay station where Impulses are passed away from one neuron to the next in a chain. Important masses of grey matter include.

Basal nuclei Thalamus Hypothalamus

Functions of hypothalamus

1) The automatic nervous system2) Appetite and satiety3) Thirst and water balance4) Body temperature5) Emotional reactions6) Sexual behavior7) Biological clocks or circadian rhythms, e.g. sleeping and waking cycles and

secretion of hormones.Brain stem:

The mid brain is the area of the brain situated around the cerebral aqueduct between the cerebrum above and the pons below

Pons:

The pons is situated in front 0f the cerebrum, below the mid brain and above the medulla oblongata.

Medulla oblongata

The medulla oblongata extends from the pons above and continuous with the spinal cord below.it is about 2.5cm long and it lies just within the cranium above the foramen magnum.

The vital centers, consisting of groups of cells associated with autonomic reflex activity, lies in the deeper structure. These are the

Cardiac Centre Respiratory Centre Vasomotor Centre Reflex centers of vomiting , coughing , sneezing and swallowing

RETICULAR FORMATION:

The reticular formation is the a collection of neurons in the core of the brainstem, surrounded by neural pathways which conduct ascending and descending nerve impulses between the brain and the spinal cord.it has a vast number of synaptic links with other parts of the brain and therefore constantly receiving information being transmitted in ascending and descending tracts.

Changes of LOC are result of impaired cerebral brain function which deprives the cells of the cerebral cortex and the reticular activating system of oxygen. The RAS is located in the brain stem, with neural connection to many parts of the nervous system.an intact RAS can maintain a state of wakefulness even in the absence of a functioning cerebral cortex interruptions of impulses from RAS or alteration’s in functioning of cerebral hemisphere cause unconsciousness.

RETICULAR ACTIVATING SYSTEM

• E.g..Spinothalamic. Auditory, visual etc.

Spinal reticular tract collateral fibers

Spinal cord

Reticular formation

Specialized sensory tract

Cerebral cortex Thalamus

Perception ofConsciousness

MEANING OF UNCONCIOUSNESS:

• Unconsciousness implies that is a stage of depressed cerebral function that

result impairment in response to sensory stimuli; abnormal loss of awareness

of self & surroundings

• Its onset is both sudden and gradual.

To produce unconsciousness a disorder must be

1. Disrupt the ascending reticular activating system ,which extends the

length of the brain stem and up to into the thalamus

2. Disrupt the function of both cerebral hemisphere

3. Metabolically depress over all brain function, as in a drug over dose.