The nervous system is divided into the central nervous system (CNS), comprising the brain and spinal cord, and the peripheral nervous system (PNS). The CNS is protected by the meninges and cerebrospinal fluid. The brain is made up of the cerebrum, cerebellum, and brainstem. The cerebrum controls sensory and motor functions. The PNS connects the CNS to the rest of the body and includes the somatic and autonomic nervous systems. The autonomic nervous system regulates involuntary functions and is divided into the sympathetic and parasympathetic systems. Common disorders of the nervous system include Alzheimer's disease, ALS, epilepsy, migraines, multiple sclerosis, Parkinson's

1. The Nervous
System
Prepared by Mickelder Kercy, MD - Instructor

2. Central Nervous System(CNS) : Brain and Spinal Cord
Peripheral Nervous System(PNS) : Autonomic Nervous
System (Sympathetic and Parasympathetic Nervous
System) and the Somatic Nervous System
(The PNS is made up of Nerves connecting the CNS to
the rest of the body)
Structure of the Nervous System

3. Motor Neurons
Sensory Neurons
Interneurons
Types of nerve cells or fibers

4. Efferent nerves fibers/cells that cause muscles to
contract, glands to secrete and organs to function
properly
Motor Neurons

5. Afferent nerves cells/fibers that carry our feelings
(heat/ pain/ cold etc..) to the Central Nervous System
Sensory Neurons

6.  Neurons that form a connection between other
neurons (e.g. in-between a motor and a sensory nerve
cell/fiber. They are neither motor nor sensory neurons
Interneurons

7.  Junction where neurons pass neurotransmitters (chemical
signals) or electrical signals to other neurons, muscle
cells, or gland cells. Composed of:
- A presynaptic ending that contains mitochondria, other
cell organelles and neurotransmitters that are released
in the synaptic space
- A synaptic space or cleft between the presynaptic and
postsynaptic endings
- A postsynaptic ending on the target cell (other neuron/
muscle cells/gland cells) that contains receptor sites for
the neurotransmitters that crossed the synaptic space
Synapse

8.  Several small molecules function as neurotransmitters.
- Glycine and glutamate (amino acids)
- Dopamine (DA), Norepinephrine (NE) & Dopamine
(DA) (cathecholamines derived from amino acids)
- Acetylcholine (ACh) & Serotonin (derived from
amino acids)
- Prostaglandins, Histamine and Y- Aminobutyric
acid (GABA) are other neurotransmitters

10. Brain : The outside is covered with gray matter and
the inside is filled with white matter
 Spinal Cord : Gray matter forms an H shape in the
inside and white matter surrounds the gray matter
Central Nervous System

13.  Protected by- Cranium/Skull
Meninges (Pia Mater, Arachnoid and
Dura Mater)
Cerebrospinal fluid (water, glucose,
protein, sodium, chloride and nutrients such as oxygen)
Blood brain barrier (glial astrocytes and
capillary cells)
 Divided into the Cerebrum, the Diencephalon, the
Brainstem and the Cerebellum
Brain

15.  Divided into the right and left Cerebral Hemispheres
 Contains convolutions/ gyri, sulcus and fissures
 Controls all sensory and motor activity
 Cortex is divided into the Frontal lobe, R & L
Parietal lobes, R & L Temporal lobes and the
Occipital lobe covered each by bones bearing the
same name
Cerebrum

17. Frontal Lobe : Executive function (speaking, learning,
reasoning, problem solving, judging, planning),
Voluntary motor activity, Emotion and Behavior
Parietal Lobe : Pain, Pressure, T°, Touch and Speech /
Language comprehension
Temporal Lobe : Memory, Hearing, Taste, Speech
Reading, Writing and Arithmetic
Occipital Lobe : Vision

19.  Divided into the Thalamus (relays all sensory impulses
to the cerebrum) and the Hypothalamus (regulates body
temperature)
Diencephalon

20.  Divided into the midbrain, the pons and the medulla
oblongata
Brainstem

21.  Midbrain : Relays information for vision and hearing
 Pons : Regulates the change from inspiration to
expiration
 Medulla Oblongata : Regulates several functions of the
autonomic nervous system
- Respiration (chemoreceptors)
- Cardiac center (sympathetic, parasympathetic system)
- Vasomotor center (baroreceptors)
- Reflex centers of vomiting, coughing, sneezing, and
swallowing

22.  Located in the back of the skull (coordination of
movement)
Cerebellum

23. Links the Brain with the rest of the body
Protected by – Vertebrae
Meninges (Pia mater, Arachnoid,
Dura mater)
Cerebrospinal fluid (water, glucose,
sodium, chloride and nutrients such as oxygen)
Blood-brain barrier (glial astrocytes
and capillary cells)
Spinal Cord

25. Somatic Nervous System : 12 pairs of cranial nerves,
8 pairs of cervical spinal nerves, 12 pairs of thoracic
spinal nerves, 5 pairs of lumbar spinal nerves, 5 pairs
of sacral spinal nerves and 1 pair of coccygeal nerves
Autonomic Nervous System : Divided into the
Sympathetic Nervous System and the
Parasympathetic Nervous
Peripheral Nervous System

26. Cranial Nerves

28. Cervical, Thoracic, Lumbar, Sacral &
Coccygeal Nerves

29.  SNS : Stimulates the adrenal gland to release
epinephrine that prepares the body for Fight and
Flight during stressful situation (Pupil dilation,
Sweating, ↑RR, dilates bronchi, ↑HR and ↑BP)
 PNS : Works during non-stressful situations
(Pupil constriction, not sweating, ↓RR, bronchi
constriction, ↓HR, ↓BP) and innervates the
digestive system (↑salivation, ↑ digestive
organs motility, ↑gallblader and bladder
contraction and relaxes the bladder sphincter )

32.  Alzheimer’s Disease : Destruction of nerve cells in
the brain causing loss of recent memory
 Amyotrophic Lateral Sclerosis : Destruction of the
motor nerves in the brain causing movement
impairment. Also called Lou Gehrig’s disease
Common Disorders associated with the
Nervous System

34.  Bell’s Palsy : Weakness or paralysis of the muscles that
control expression on one side of the face

35.  Disk Disorders : When the intervertebral disks
deteriorate causing pain and shortening of height

36.  Encephalitis : Inflammation of the brain

37.  Epilepsy and seizures : Interference of electrical
impulses within the brain causing uncontrollable
movement of the limbs and body

38.  Migraine Headache : flashes of light, blind spots,
tingling in your arm/leg or sensitivity to light/noise
often precedes the headache
 Tension Headache : Due to stress
 Cluster Headache : Felt behind the eyes or temples.
May last for weeks to months than stops (cycle)
 Post-Traumatic Headache : Post trauma

39.  Huntington’s Chorea : Hereditary disease affecting
the cerebral and basal ganglia causing imbalance,
lack of coordination, difficulty swallowing and
rigidity

40.  Hydrocephalus : Excessive amount of Cerebro-
spinal fluid in the ventricles of the brain

42.  Meningitis : Inflammation of the meninges that
surround the brain and the spinal cord

43.  Multiple Sclerosis : Body’s antibodies become
confused and attack the myelin sheath surrounding
the nerves in the brain and spinal cord causing vision,
sensation and movement impairment

44.  Neuralgia : Nerve pain
 Parkinson’s Disease : Degeneration of nerves in the
basal ganglia causing a loss of dopamine resulting in
the lack of movement control

45.  Sciatica : Pain running down the sciatic nerve

47.  Spina Bifida : Failure of the spine to close properly
during the 1st month of pregnancy

49.  Spinal cord Injuries : Quadriplegia, Paraplegia and
Hemiplegia
 Stroke : Cerebro-vascular accident due to ↓ or
cessation of blood flow to the brain

51.  Transient Ischemic attack : Mini-strokes lasting a few
minutes
 Concussion : Injury caused by a blow to the head.
May lead to a loos of consciousness
 Contusion : Bruising of the brain

52. The End