The body control centre The Nervous System The body control centre

Functions of the Nervous System Receives, stores & interpret information e.g. from eyes & ears Controls activities of all body systems to maintain homeostasis within the body Homeo = combining form meaning the same Controls all muscle movements including speech

Divisions of Nervous System 1. Central Nervous System (CNS) Brain Spinal cord

Divisions of the Nervous System cont’d 2. Peripheral Nervous System (PNS) These nerves branch out from the CNS to all parts of body There are: 12 pairs of cranial nerves 31 pairs of spinal nerves

Peripheral Nervous System Nerves of PNS function in a voluntary Manner Peripheral nerves carry impulses from receptors in skin, eyes, ears nose to CNS. These peripheral nerves are called sensory or afferent nerves Peripheral nerves also carry impulses from CNS to body organs These nerves are called motor or efferent nerves

Division of the Nervous System cont’d 3. Autonomic System (ANS) Nerves carry involuntary impulses to smooth muscle, cardiac muscle & some glands

Divisions of Nervous System Central Nervous System Peripheral Nervous System Afferent (sensory) neurons from organs muscles & glands Efferent (Motor) neurons to Muscle & glands Autonomic Nervous System

Word component Word Root Combining Form Meaning Neur Neuro nerve

Neurons and their Function Specialised cells of the Nervous System Cells responsible for transmission of nerve impulses

What does a neuron look like? Network of nerves or neurons pg1

Word Components Word Root Combining form Meaning Plex Plex/o network of nerves Cephal Cephal/o head Encephal Encephal/o brain cerebr cerebr/o cerebrum of the brain Act 2

The Brain Cerebrum – large brain Cerebellum – Little brain

Cerebral Vascular Accident (CVA) Is a result of disruption to blood supply (i.e. ischaemia) to part of the brain Ischaemia to cerebrum can cause brain cells to die and is known as an infarct Paralysis and loss of speech can occur because cells of the cerebrum control many body movements Severity depends on what part of the brain is affected

Cerebral Cortex Is the outer layer of cerebrum Contains motor and sensory areas Responsible for consciousness and intelligence

Word Components Word Root Combining form Meaning ventricul ventricul/o Ventricle crani crani/o bones of the skull (cranium) gangli gangli/o knot of group of nerve cell bodies

More word components Mening mening/o, mening/i membrane Radicul radicul/o spinal nerve roots Myel myel/o marrow, spinal cord Pleg -plegia paralysis Aesthesi aesthesi/o sensation Narc Narc/o stupor – abnormal sleep induced by a drug Alges Algesi/o, -algesia sense of pain Rachi rachi/o spine Act 3

Other parts of brain Part Combining form Function Cerebrum cerebr/o responsible for thoughts,judgements,memory,sensation cerebellum cerebell/o coordinates voluntary movement Thalamus thalam/o grey matter; neurons relays sensory messages e.g. pain to cerebral cortex Hypothalamus has neurons that control body temperature, sleep, appetite, & emotions Brain Stem – pons medulla oblongata relays messages to cerebrum, cerebellum, & spinal cord responsible for breathing, heart rate, and heat

Thalamus Hypothalamus CRANIUM CEREBRUM PONS CEREBELLUM MEDULLA OBLONGATA THE BRAIN Thalamus Hypothalamus

Spinal Cord Extends from the medulla oblongata to the second lumbar vertebra Carries nerves that affect limbs &lower parts of body Is the pathway for impulses to & from brain Inner section composed of grey matter Outer section composed of white matter

Meninges What are the layers surrounding brain & spinal Cord? Dura mater – outer membrane contains channels for blood to enter brain tissue. Subdural space is below the dura & contains blood vessels Arachnoid membrane – next layer. Subarachnoid space contains cerebrospinal fluid (CSF) Pia mater – layer closest to brain

Rachiocentesis Procedure to take sample of CSF from spinal cord fro testing Also known as a lumbar puncture or spinal tap Act 4

Conditions of Nervous System Meaning Alziemers Disease deterioration of mental capacity causing degeneration of neurons in cerebral cortex Palsy Bells Palsy Cerebral Palsy unilateral facial paralysis due to disorder of facial nerve partial paralysis & lack of muscular coordination due to damage to cerebrum during birth Parkinson’s Disease degeneration of brain nerves leading to tremors, weakness, & slowness of movement Multiple Sclerosis conduction of nerve impulses is prevented due to parasthesia, leading to muscle weakness, unsteady gait & paralysis Epilepsy recurrent seizures & /or fitting

Word Components Word part Meaning -lexia condition of speech/ words mening/o meninges myel/o spinal cord or bone marrow occipit/o occipit, posterior region of the skull -paresis weakness, slight paralysis -plegia paralysis plexus network of vessels or nerves synapse membrane to membrane contact of one nerve cell to another

Abbreviations CAT or CT Scan Computerized Axial Tomography- x rays are beamed at different angles to produce images and examine soft tissues of the body EEG Electroencephalogram – recording of brain waves MRI Magnetic Resonance Imaging – uses movement of hydrogen to a large magnetic field to produce images of internal soft tissues

Conditions & Terms anaesthesia loss of sensation resulting from medication analgesia loss or reduction of pain sensation encephalitis inflammation of the brain hemiparesis weakness on one side (half) of body hemiplegia paralysis of one side (half ) of body hydrocephalus excessive amount of cerebrospinal fluid around the brain paralysis complete or partial loss of controlled movement sciatica pain that radiates down the sciatic nerve, affecting buttock, thigh, and foot