nervous system
- co ordinates all activities inside and outside the body
- entire body covered with fibres called nerves
- over 100 billion nerve cells in body called neurons
3 divisions of the nervous system
- Central Nervous System
- Peripheral Nervous System (outer)
- Autonomic Nervous System
two divisions of autonomic nervous system
Sympathetic division: stimulates or speeds up activity and prepares the body for stressful situations
Parasympathetic division: operates under normal, non-stressful conditions and helps restore & slow down activity, thus keeping the body in balance
central nervous system
- brain, spinal cord, spinal nerves and cranial nerves
- controls consciousness, mental activities, voluntary functions of the 5 senses, and voluntary muscle actions including all body movement and facial expressions
peripheral (outer) nervous system
- connects outer part of the body to the central nervous system
- has sensory & motor nerves
- carries impulses to and from the central nervous system
autonomic nervous system
- controls involuntary muscle
- regulates smooth muscles, glands, blood vessels, the heart and breathing
brain
- largest and most complex nerve tissue in the body
- contained in the cranium
- controls sensation, muscles, glands, thinking and feeling
- sends telegraphic images through 12 pairs of cranial nerves
spinal cord
- originates in the brain and travels down the trunk, protected by the spinal column
- 31 pairs of nerves exit the spinal cord and supply the body
neuron
- nerve cell, the primary structural unit of the nervous system
- composed of cell body, nucleus, dendrites and an axon
dendrites: receive info from other neurons
axons: send messages away from the cell body to other neurons, glands, muscles and organs
nerves
- whitish cords made up of bundles of nerve fibers held together by connective tissue
- originate in the brain and spinal cord and branch off in all parts of the body
- transmit impulses
what are the 2 types of nerves?
- sensory/afferent
- motor/efferent
sensory nerves
afferent
-carry impulses from the sense organs to the brain, where sensation is experiences
-sensory nerve endings (receptors) are located close to the surface of the skin
motor nerves
efferent
-carry impulses from the brain to the muscles or glands to produce movement or secretion
reflex
an automatic nerve reaction to a stimulus that involves the movement of impulses from a sensory receptor along the afferent neuron to a muscle, causing a reaction
alzheimer’s
- pathology of the brain caused by atrophy of areas of the brain
- characterized by gradual and insidious progression of symptoms like confusion, memory failure, restlessness, and speech disturbances
- a client with Alzheimer’s may require a family member/advocate to help them understand the service being provided and to give consent on their behalf
epilepsy
- results from abnormal and irregular discharges of electrical activity in the brain
- individuals with epilepsy may experience sensory disturbances, seizures, abnormal behaviour and loss of consciousness
absence seizures
brief periods of unconsciousness, no convulsions
partial/focal seizures
no loss of consciousness, the person may exhibit abnormal behaviour like walking around in circless
tonic-clonic seizures
the person loses consciousness, drops to the floor and experiences convulsions
*often preceded by warning signs that the person is familiar with
clinical depression
- linked to decreased levels of neurotransmitters like serotonin and norepinephrine
- may be unipolar or bipolar (manic-depressive)
SAD: seasonal affective disorder, linked to lack of sunlight in the winter months
schizophrenia
chronic brain disorder where the person may experience delusions, hallucinations, disorganized speech, trouble thinking and a lack of motivation
panic disorder
anxiety disorder characterized by a feeling of intense fear with an increased heartrate, difficulty or increased breathing, and perspiration
obsessive-compulsive disorder `
characterized by a series of obsessions and compulsions that are extremely distressing to the sufferer and interfere with their day-to-day lives
anorexia nervosa
eating disorder characterized by an intense fear of weight gain that becomes an obsession with severely restricted food intake and excessive physical exercise
