Nervous System Flashcards
The nervous system
Coordinates all activities inside and outside the body
Entire body covered with fibres called nerves
Over 100 billion nerve cells in the body called neurons
What are the 3 divisions of the nervous system?
- Central nervous system
- Peripheral nervous system (outer)
- Autonomic nervous system
Central nervous system
Brain, spinal cord, spinal nerves and cranial nerves
Controls consciousness, mental activities, involuntary functions of five senses (seeing, hearing, feeling, smelling and tasting) and voluntary muscle actions including all body movements and facial expressions
Peripheral nervous system
Connect outer part of the body to CNS (Central nervous system)
It has both sensory and motor nerves
It carries impulses, or messages to and from the central nervous system
Autonomic nervous system
Controls involuntary muscles
Regulate smooth muscles, glands, blood vessels, the heart and breathing
The organs affected by the autonomic system receive nerve cells or fibres from its two divisions which are
Sympathetic division
Parasympathetic division
Sympathetic division
Stimulate or speed up activity and prepares the body for stressful situation
Parasympathetic division
Operates under normal, no stressful conditions and help restore and slow down activity, thus keeping the body in balance
The brain and spinal cord
The brain is the largest and most complex nerve tissue in the body
Contained in the cranium
Control sensation, muscles, glands, thinking and feeling
Send telegraphic images through 12 pairs of cranial nerves
Spinal cord part of the CNS originates in the brain and travels down the trunk - protected by the spinal column
31 pairs of nerves exit the cord and supply the body
Nerve cell structure and function
A neuron or nerve cell is the primary structural unit of the nervous system
It is composed of: cell body, nucleus, dendrites and an axon
Dendrites
Receive information from other neurons
Axons
Send messages away from the cell body to other neuron, glands, muscles and organs
Nerves
Are whitish quartz, made up of bundles of nerve fibres held together by connective tissue, through which impulses are transmitted
Nerves have their origin in the brain and spinal cord and send their branches to all parts of the body
What are the two types of nerves?
- Sensory nerves / afferent nerves 
2. Motor nerves/ efferent nerves
Sensory nerves
Carries impulses or messages from the organs to the brain where sensation such as touch, cold, heat, sight, hearing, taste, smell, pain and pressure are experienced
Sensory nerve endings called receptors are located close to the surface of the skin, as impulses pass from the sensory nerves to the brain and back through the motor nerves to the muscles; A complete circuit is established, resulting in movements of the muscles
Motor nerves
Carries impulses from the brain to the muscles or glands
These transmitted impulses produce movements
Pathologies of the nervous system
Pathologies affecting the nervous system can be broadly categorized into three groups which are:
1 Pathologies affecting the brain
2 Pathologies affecting the central nervous system
3 Pathologies affecting the peripheral nerves
Pathologies affecting the brain
- Alzheimer’s diseased pm
Alzheimer’s disease is caused by atrophy of areas of the brain
This condition is characterized by gradual and insidious progression of symptoms such as confusion, memory failure, restlessness, and speech disturbances
It usually occurs in the elderly but can occasionally start in a person of middle-age
A client with Alzheimer’s may require a family member to help them understand the service being provided, and to give consent of their behalf
Pathologies of the brain
- Seizure disorders
Seizures or convulsions (aka epilepsy) result from abnormal and irregular discharges of electrical activity in the brain
During these episodes the individual May experience sensory disturbances, seizures, abnormal behaviour and loss of consciousness
The causes of seizure disorders are unknown but they have been linked to brain injury either before or after birth and chemical imbalances
Seizures are sometimes brought on by flashing or flickering lights or other stimulus is that is irritating to the clients brain
Absence seizures
Brief periods of unconsciousness and the client may not be aware that anything has happened
there is no convulsion
Partial or focal seizures
Do not involve any loss of consciousness
The person may exhibit unusual behaviour such as walking around in a circle or saying things that do not make sense
Tonic-clonic seizures
Are often preceded By a warning sign that the client is aware of
In the seizure itself, the client loses consciousness, drops to the floor, and there is jerking of the muscles caused by repeated contractions and relaxations of the major muscle groups

How can you support someone who is having a seizure?
Protect the person from injury during a seizure
Do not attempt to restrain the person in anyway
Make sure they cannot fall
Cushion any hard or sharp surfaces
After the seizure, do not continue any treatment but place the client in a quiet, warm place until they are able to leave
arrange for safe transportation

Mood disorders
1. Depression
A common disorder which affects approximately 20% of the population
More common in women
It may be unipolar (depression only) or bipolar (Alternating depression and mania)
It’s normal for people to feel depressed if an incident takes place in their lives (situational depression)
Clinical depression is linked to decreased levels of neurotransmitters such a serotonin and norepinephrine
Can be controlled with medication‘s to regulate brain chemicals
Seasonal affective disorder (sad) is a specific type of depression which is linked to a lack of daylight in the winter months
Mood disorders
2. Schizophrenia
A psychotic disorder of thought and language
include disorganized speech, delusions, visual and auditory hallucinations
Onset is usually early adulthood
The cause is abnormality in brain structure and neurotransmitters
Symptoms can be controlled by medications that regulate the neurotransmitters

Mood disorders
3. Anxiety
These include panic disorders and obsessive compulsive disorders
Panic disorder is characterized by a feeling of intense fear with racing heart, increased breathing rate, and sweating
Obsessive compulsive disorder is characterized by repetitive thoughts and repeated acts that are time consuming or distressing to the person
(they may have to wash their hands repeatedly, check the stove or door lock repeatedly before they can leave the house or perform tasks in a particular number of times or in a particular order)
OCD disorder is also seen people with other neurological disorders such as autism
These disorders are frequently seen in several members of the family
Mood disorders
- Eating disorders
i) anorexia nervosa
Eating disorders include:
Anorexia nervosa
Binge eating
Bulimia
They involve:
Serious disturbances in eating
Excessive concern over body weight and shape
Anorexia nervosa involves an intense fear of gaining weight
- most common in young women
- begins when a young woman is overweight or believes she is over weight
- obsession over weight reduction
- severely restricted food intake
- excessive frequent physical exercise
Psychological issues are involved in which a person tries to exert control in their life by controlling food intake and weight
Many systems are affected by the malnutrition that results: menstruation stops, breast disappear, bones become weak, the person is constipated, heart-size decreases, and a fine hair (lanugo) may develop on the skin
Death may occur due to starvation or damage to the heart or other organs
Mood disorders
4. Eating disorders
ii) binge eating
Characterized by eating rapidly, until uncomfortably full, eating large amounts when not hungry, eating alone because of embarrassment
Mood disorders
- Eating disorders
iii) Bulimia nervosa
- more common in women
- usually begins in teenage years
- consists of binge eating followed by self induced vomiting or abuse of laxatives
Problems that result are dental disorders and damage to the throat & stomach
Electrolyte imbalance may result with loss of necessary minerals
The individuals weight may fluctuate
Some people with anorexia nervosa also have bulimia
Multiple sclerosis
Pathology of the central nervous system
Starts in early adulthood
More common in northern climates
2x more common in women
The myelin covering of the nerves in the brain, spinal cord and optic nerve is affected *
Symptoms vary depending on the location of the demyelination
Symptoms:  Visual changes, numbness and spasticity of muscles, changes in gait or inability to walk, fatigue and speech disturbances
Symptoms may occur and then relapse
Some people have lengthy periods of remission and symptoms progress very slowly *
Other cases may progress rapidly
Google source : Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system. In this disorder, your immune system attacks the myelin sheath or the cells that produce and maintain it. This causes inflammation and injury to the sheath and ultimately to the nerve fibers that it surrounds.
Amyotrophic lateral sclerosis (ALS)
Aka: Lou Gehrig’s disease
(Pathology of the central nervous system)
Neurological disorder that affects motor function
Symptoms: weakness, spasticity or stiffness, and impaired fine motor control
Some may experience difficulty swallowing, speaking or breathing
Tends to affect older adults
Avg. survival period of 2-5 years
Google source:
a progressive neuromuscular disease. ALS is characterized by a progressive degeneration of motor nerve cells in the brain (upper motor neurons) and spinal cord (lower motor neurons).
Spinal cord injury
Pathology of the central nervous system
Symptoms depend on the level of injury and the amount of damage
A complete SCI implies there is no movement or sensation below the level of injury
Complete severance of the cord is rare
A incomplete spinal cord injury may result in paralysis of the legs or damage to the motor nerves while retaining some sensation
Cerebral palsy
Pathology of the central nervous system
Motor disorder
Affects muscle coordination
Loss of muscle control
Caused by Damage to the brain smaller areas during fetal life, birth or infancy
Causes during fetal life include rubella infection, toxemia, malnutrition during pregnancy, or damage during birth resulting in reduced oxygen
Causes during childhood are trauma or seizures

Not progressive but is irreversible
Intelligence may or may not be affected speech may be impaired
Parkinson’s disease
Pathology of the central nervous system
Progressive, degenerative, neurological disorder
destruction of dopamine producing neurons in the brain
Onset is over 50 years of age but may start in early 40’s
Muscles may alternately contract and relax, causing tremors or rigidness
Difficulty initiating movement or walking
Reflex
A REFLEX is 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 (for example, the quick removal of the hand from a hot object)
Reflexes do not have to be learned, they are automatic
