the nervous system. gathers information both externally and internally transmits this information...
TRANSCRIPT
The Nervous System
• Gathers information both externally and internally
• Transmits this information for processing
• Processes the information to determine the best response
• Sends information to the muscles, glands and organs so they can respond appropriately
The Nervous System
The Nervous System
Central Nervous System (CNS)
• Brain and Spinal Cord
• Main Control Center
• Processes information
• Sends instructions to other parts of the body
Peripheral Nervous System (PNS)
• Nerves that extend throughout the body
• Gathers and delivers information
• Works with the Central Nervous System
The Nervous System
Structure of the Neuron• Cell body• Dendrites receive and carry information toward the
cell body• Axon carries nerve impulses away from the cell
body• Glial cells protect, support and assist neurons• In the PNS, the glial cells are Schwann cells
– Schwann cells are wrapped by a myelin sheath
Neuron
The Central Nervous System
• BrainBrain Stem: Joins brain to spinal cordCerebellum: Center of coordinationCerebrum: Largest part of brain, conscious thoughtCerebral Cortex: Sensory, motor and association areas
• Spinal CordRelays nerve impulses to and from the brainControls spinal reflexes
Parts of the Brain
• 2 cerebral hemispheres
– Further divided into lobes • Parietal Lobe – somatic sensory area, impulses
traveling from the body’s sensory receptors are localized & interpreted here
– Ex. pain, cold, touch
• Occipital Lobe – visual area• Temporal Lobe – auditory area and olfactory area• Frontal Lobe – primary motor area – skeletal muscles,
also specialized area for fine motor control such as speech
Cerebral Cortex – sensory and motor areas
Cerebellum
• 2 hemispheres– Under occipital lobe of cerebrum
• Balance
• Coordinates body movements (makes movements smooth)
Brain Stem
• 3 inches long, diameter of thumb, base of brain
• 3 parts:– Midbrain – reflex centers for hearing and vision– Pons – (means bridge), center for breathing– Medulla oblongata – merges into spinal cord
• Automatic, homeostatic functions
• Such as: heart rate, blood pressure, breathing, swallowing, vomiting and digestion
Spinal Cord
• Continuation of brain stem
• 2-way conduction pathway to and from the brain and a major reflex center
• Cushioned and protected by meninges – Meninges = connective tissue membranes
• 31 pairs of spinal nerves arise from the spinal cord
The Peripheral Nervous System
Somatic Nervous System• Controls voluntary responses of
skeletal muscles
• May involve some reflex reactions
Autonomic Nervous System• Controls the activities of smooth
muscles, organs, and glands
• Divided into:
Sympathetic Nervous System which controls the response of the body to stress
Parasympathetic Nervous System which controls the functions of the body related to rest and digestion