ANATOMY & PHYSIOLOGY/THE NERVOUS SYSTEM The Nervous System

Introduction to the Nervous System The role of the Nervous System is to control communication between different parts of the body. The Nervous System generates electrical impulses to send signals throughout the body.

The Jobs of the Nervous System The Nervous System has 3 main functions: 1. Monitor changes inside and outside the body The changes are called stimuli and the gathered information is called sensory input. 2. Process and interpret sensory input Making decisions to respond to sensory input is called integration. 3. Cause a response by activating muscles or glands These responses are called motor output.

Organization of the Nervous System The Nervous System is made of 2 main parts: 1. The Central Nervous System (CNS): Brain and Spinal Cord 1. The Peripheral Nervous System (PNS) Nerves that branch out from the CNS

The Brain The brain is composed of about three pounds of wrinkled, pinkish-grey tissue. The brain is protected by:  Three layers of connective tissue called the meninges  The shock absorbing cerebralspinal fluid  The bones of the skull

Parts of the Brain The brain can be divided into four regions:  Cerebral Hemispheres  Diencephalon  Brain Stem  Cerebellum

The Cerebral Hemispheres The paired cerebral hemispheres of the brain are collectively known as the cerebrum. The cerebrum is composed of two materials:  The outer grey matter which contains dendrites and neuron bodies  The inner white matter which contains bundles of nerve fibers carrying information to the outer grey matter. This is the largest area of the brain and controls speech, memory, logical and emotional response, conciousness, interpretation of sensation and voluntary movement.

The Cerebral Hemispheres Continued The cerebrum is divided into the right and the left hemisphere, which are connected by a large bundle of nerve fibers called the corpus callosum. The right side of the cerebrum controls the left side of the body and visa versa.  The right hemisphere is associated with creativity & artistic ability  The left hemisphere is associated with analytical and mathematical ability

Lobes of the Cerebral Hemispheres Each hemisphere of the brain is divided into four areas called lobes.  Parietal Lobe – processes information from skin receptors (pain, temperature etc)  Occipital Lobe – processes information from the eyes  Temporal Lobe – processes information from the ears and nose  Frontal Lobe – oversees control of skeletal muscles

Lobes of the Cerebral Hemispheres

The Diencephalon The diencephalon is also known as the interbrain and is surrounded by the cerebral hemispheres. The major structures of the diencephalon include:  Thalamus – first stop in sensory processing  Hypothalamus – regulates body temperature, water balance and metabolism, forms part of the limbic system which controls sensations of thirst, appetite, pain and pleasure  Pituitary Gland – produces and regulates many hormones

The Brain Stem Located at the bottom of the brain and approximately the size of a thumb. Major structures of the brain stem include:  Midbrain – controls reflexes related to vision and hearing  Pons – controls breathing  Medulla Oblongata – controls heart rate, blood pressure, breathing, swallowing and vomiting

The Cerebellum Has an appearance similar to a cauliflower. Composed of both white and grey matter and two hemispheres like the cerebral hemispheres. Controls movement, balance and equilibrium

Can You Label These Parts? A B C D E F G H I J Frontal Lobe Parietal Lobe Occipital Lobe Temporal Lobe Corpus Callosum Pons Spinal cord Medulla Cerebellum Pituitary Gland

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