Introduction To Central
Introduction to CNS
• CNS is composed of brain and spinal cord.
• Primary function are to coordinate and control
the activity of other body systems.
• Involved the synaptic processes which release
different kind of neurotransmitters
– Ach, NE, Serotonin, Dopamine etc
– Some mental illnesses & pathological conditions are
associated with abnormal changes in the amount or
activity of neurotransmitter
– Many drugs that act on the CNS do so by affecting
neurotransmitter concentrations and activity.
Division of Nervous System
Parts of the brain
• 3 main parts
– Cerebrum ( brooomm broommm..)
• Controlled all the higher intellectual
abilities of human beings
• Largest and uppermost part of the brain
• Divided into right and left cerebral
– Outer cerebral cortex
– Inner cerebral medulla
•Your “thinking brain”
•It’s convoluted (folded)
to have more space
•In general, the larger the
cortex the more
intelligent the species
• Contains the cell bodies of neurons (gray matter)
that control the voluntary activity of the body
• The cortex is subdivided into 4 main lobe:
– Frontal lobes (Control of muscle movement, the
motor components of speech, abstract thinking &
problem solving activity)
– Parietal lobes (Sensory sensation eg; touch, pressure,
pain, temperature & vibration)
– Temporal lobes (memory & language functions)
– Occipital lobes (vision)
• Composed of myelinated axons (white matter)
of the neurons.
• The axons conduct nerve impulses to and from
different areas of the nervous system.
• There are a group of cell bodies (gray matter) in
the medulla known as basal ganglia or
– Basal ganglia involved in the regulation of motor
– Degeneration of basal ganglia is responsible for
parkinson’s disease and huntington chorea
• Brainstem continuous with spinal cord
and extends up the cerebrum.
• Controlled involuntary activity
• Main part of brain stem
• Located on the top of the brainstem
• Regulates sensory impulses (temperature,
touch & pain) travelling to the cortex.
• Some tranquilizers and analgesic drugs
affect sensory information by interfering
with the function of the thalamus.
• Located below the thalamus
• Controls many body function including
temperature, water balance, appetite,
sleep, the autonomic nervous system and
certain emotional and behavioural
• The pituitary gland (master gland- which
regulates the function of many endocrine
glands) is attached to the hypothalamus.
• Located below the hypothalamus
• Involved in the regulation of respiration
and serves as a relay station for nerve
fibres travelling to other brain areas.
Medulla Oblongata, MO
• Lies just above the spinal cord.
• Within the MO, are the three vital centers: cardiac
(heart), vasomotor (blood pressure) and respiratory
• Normal functioning of the vital centres is essential for life support. Injury to MO frequently results in death.
• Overdose with drugs such as alcohol and barbiturates,
causes death by depressing the function of the vital
• Several important reflexes are also regulated by the MO, including swallowing, coughing, vomiting and gagging.
• Lies behind brainstem and below the cerebrum.
• Divided into right & left cerebellar hemispheres
• The major function are to coordinate body
movement and posture and help to maintain
• Drug that depress the cerebellum, such as
alcohol, usually decrease body coordination and
• The spinal cord is a collection of nerve axons
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