NERVOUS SYSTEM &

SPECIAL SENSESBy: Alyce Baughman and Jessica Woodruff

Period 3

FUNCTION OF THE SYSTEM

-Main function is to control the operation and movements of the body based on the sensory information it gathers, both internally and externally

FUNCTIONS INCLUDE:-To maintain your consciousness-To help you respond to your senses-To help coordinate what you sense and feel-To allow learning and memory-To control other body systems

NEURON-Includes a cell body, dendrites, and an axon-Dendrites and the cell body provide receptive surfaces-Axon arises from the cell body and can be enclosed in a myelin sheath and a neurilemma-Either multipolar, bipolar, or unipolar

SYNAPSE-Junction between 2 neurons-Presynaptic neuron carries an impulse into a synapse; post-synaptic neuron responds-Axons have synaptic knobs at distal ends, which secrete neurotransmitters-Neurotransmitter released when nerve impulse reaches end of axon-Neurotransmitter reaching the postsynaptic neuron membrane may trigger nerve impulse

STRUCTURES OF THE BRAIN

-Composed of100 billion multi-polar neurons -Multi-polar neurons communicate with one another and with neurons in other parts of nervous system-Subdivided into the cerebrum, diencephalon, brainstem, and cerebellum

FUNCTIONS OF THE BRAIN

CENTRAL NERVOUS SYSTEM(CNS)

-Nerves of the brain and spinal cord-Central core of the body

PERIPHERAL NERVOUS SYSTEM

-Cranial nerves arising from the brain

-Spinal nerves arising from the spinal cord

-Sensory neurons running from stimulus receptors that inform the CNS of the stimuli -Motor neurons running from the CNS to the muscles and glands, called effectors, that take action.

CNS AND PNS

CENTRAL VERSES PERIPHERAL

AUTONOMIC NERVOUS SYSTEM-Functions independently(autonomously) and without conscious effort-Regulates the visceral activities that maintain homeostasis-Reflexes controlled from the nerve centers in the brain and spinal cord

SUB-LEVELS Sympathetic Parasympathetic

-Responds to stressful and emergency conditions-Leave the spinal cord and synapse in paravertebral ganglia

-Most active under ordinary conditions-Begin in the brainstem and sacral region of the spinal cord and synapse in ganglia near viscera

SOMATIC SENSES-Senses we feel with our bodies-Include sensations of touch and pressure, pain and temperature, and our muscle senses (proprioception)Example: If you feel someone touch your arm or face

SENSE OF TASTE & SMELL-The perception of chemicals in the air or in our food

-Tastants, chemicals in foods, are detected by taste buds-Taste buds consist of special sensory cells-When stimulated, these cells send signals to specific areas of the brain, which make us conscious of the perception of taste.-Specialized cells in the nose pick up odorants, airborne odor molecules-Odorants stimulate receptor proteins found on hairlike cilia at the tips of the sensory cells-Initiates a neural response. *Ultimately, messages

about taste and smell converge, allowing us to detect the flavors of food*