1. Body Systems and Disorders
Nervous System
Body Systems and Disorders

2. Nervous System Consists of two divisions:
Central Nervous System (Brain and Spinal Cord) – CNS
Peripheral Nervous System
12 pairs of cranial nerves
31 pairs of spinal nerves
Autonomic nervous system

3. CNS Functions Communication and coordination system in the body
Seat of intellect and reasoning

4. The Brain Weighs about 1400 grams or 3 pounds
100 billion neurons (nerve cells) – transmit messages from one cell to the next.
Meninges – membranous coverings of the brain.
Cerebrospinal fluid – liquid shock absorber protecting brain and spinal cord.
Without oxygen, brain damage occurs within 4-8 minutes

5. Cerebral Functions Frontal lobe – controls voluntary muscle movement.
Parietal lobe – Receives & interprets nerve impulses from the sensory receptors for pain, touch, heat, cold, and balance. Also helps to determine distance, sizes, and shapes.
Occipital lobe – houses visual area controlling eyesight.

6. Cerebral Functions con’t
Temporal lobe – houses smell (olfactory) and auditory areas. Is also the central language area for speech understanding and comprehension.
Limbic lobe – encircles top of brain stem. Influences unconscious and instinctive behaviors that relate to survival.

7. Spinal Cord
Function – carry messages from the sensory neurons to the brain for interpretation and the response is carried back from the brain through the motor neurons to the muscles and glands.
Begins at foramen magnum of the occipital bone
Ends at the second lumbar vertebrae
31 pairs of spinal nerves
Protected by meninges and other tissues

8. Disorders
Meningitis – inflammation of linings of brain an spinal cord. Cause: may be bacterial or viral.
Symptoms: include
headache, fever and stiff
neck. May lead to
paralysis, coma, and death.
Treatment: antibiotics if
bacterial.

9. Disorders
Epilepsy – seizure disorder of the brain. Believed to be a result of spontaneous, uncontrolled cycles of electrical activity in the neurons of the brain. Cause is uncertain.
Treatment: anticonvulsant drugs, i.e. phenobarbital, dilantin and tegretol.
Cerebral palsy – disturbance in voluntary muscular action due to brain damage. Caused by abnormalities in the parts of the brain that cause movement.
Characteristics: head rolling, grimacing, and difficulty in speech and swallowing. There is usually no impairment of the intellect; the person frequently has normal or above normal intelligence.

10. Disorders
Hydrocephalus –increased volume of cerebrospinal fluid within ventricles of the brain.
Cause: blockage in third or fourth ventricles.
Symptoms: enlargement of head usually noticed at birth.
Treatment: bypass (shunt) operation to divert cerebrospinal fluid around blocked area.
Parkinson’s disease – characterized by tremors, shuffling gait, pill-rolling (movement of thumb & index finger), and muscular rigidity.
Cause: may be decrease of neurotransmitter dopamine.
Treatment: drugs to help with control of the symptoms.

11. Disorders
Multiple sclerosis – chronic inflammatory disease of the CNS. Immune cells attack the myelin sheath of nerve cell axons.
Cause: unknown
Symptoms: include weakness of extremities, numbness, double vision, tremorus movement of eyes, speech problems, loss of coordination, and possible paralysis.
Treatment: drugs, adequate rest, exercise, and minimal stress.
Alzheimer’s disease – progressive disease. Nerve endings in cortex of brain degenerate and block signals that pass between nerve cells.
Symptoms: from short-term memory loss to inability to recognize oneself.

12. Disorders Spinal cord injuries
Quadriplegia – usually injury to spine area C1-C4. Loss of movement and feeling in the trunk and all four extremities with the accompanying loss of bowel, bladder, and sexual function.
Paraplegia – usually injury to spine area T1-T12 & L1-L5. Loss of movement and feeling in the trunk and both legs. Loss of bladder, bowel, and sexual function are common.

13. Peripheral Nervous System
Nerves that connect the brain and spinal cord with sensory receptors, muscles, and glands. Divided into two subcategories: Afferent Peripheral system and Efferent Peripheral system.
Afferent or sensory nerve – nerve fibers carry impulses from the sense organs to the brain or spinal cord.
Efferent or motor nerve – nerve fibers carry impulses from the brain or spinal cord to muscles or glands.
Efferent Peripheral system further subdivided into the Somatic Nervous System and the Autonomic Nervous System.

14. Autonomic Nervous System
Nerves, ganglia, and plexuses which carry impulses to all smooth muscle, secretory glands, and heart muscle
Sympathetic system – nerves extend to all vital internal organs including liver, pancreas, heart, stomach intestines, blood vessels, iris of eyes, sweat glands, and bladder. If in danger or under stress, the body prepares to run or fight. Sympathetic nervous system sends the message to adrenal medulla which secretes its hormones to prepare the body for this action.

15. Autonomic Nervous System con’t
Parasympathetic system – 2 active nerves; vagus and pelvic. Effects are to counteract the effects of the sympathetic system.
The two systems operate as a pair, striking a nearly perfect balance when the body is functioning properly.

16. Disorders Neuritis – inflammation of a nerve or a nerve trunk.
Symptoms: severe pain, hypersensitivity, loss of sensation, muscular atrophy, weakness and paresthesia (tingling, burning, and crawling of the skin).
Causes: may be infectious, chemical, or other conditions such as chronic alcoholism.
Treatment: drugs; other remedies based on cause.

17. Disorders Bell’s palsy – involves the 7th cranial nerve.
Cause: unknown
Symptoms: appears to have had a stroke on one side of the face. Eye doesn’t close properly, mouth droops, numbness on affected side.
Treatment: no standard treatment. Some studies show that steroid and antiviral drugs may be effective.

18. Test of sensory-motor function
Includes tests that are general or specific measures of any or all of the five senses and those that assess fine or gross motor skills.
Tests can include any or all of the following:
1.Mental Status 2. Cranial Nerves 3. Motor Exam 4. Reflexes 5. Coordination and Gait 6. Sensory Exam

19. Medical Terminology