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Learn about the basic components and functions of the nervous system, including neurons, the central and peripheral nervous system, and the different senses. Understand how the nervous system gathers and interprets information from the body and the external world. Explore the brain, spinal cord, and nerves, and discover how they control voluntary and involuntary movements.
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The basic component of the nervous system is a neuron. • Neuron-conducting cells that constitute the brain, spinal column, and nerves, consisting of a nucleated cell body with one or more dendrites and a single axon. Also called nerve cell.
Neurons have 3 basic parts to them Cell Body [soma] Axon Dendrites
The nervous system has two basic functions. • It gathers information • It interprets information
This information comes from inside the body and from the world outside the body. The nervous system responds to this information as needed.
The way your body interacts with the world is through : • Stimulus • Response
Stimulus-something that excites or causes a physical response in an organism.
The Brain The nervous system has two parts. • Central nervous system • Peripheral nervous system
Brain Spinal Cord The Central Nervous System • Central or CNS- Consists of the brain and spinal cord
Central Nervous System Peripheral Nervous System • Peripheral- nerves connecting CNS to muscles and organs
The CNS processes and responds to all of the messages coming form the peripheral nervous system. Normally, information is transferred from the PNS to the CNS and Back. However, in some cases the PNS causes a response without involving the CNS.
PNS The PNS has two types of nerves: Somatic and Autonomic nerves. • Somatic-control conscious movement. • Autonomic-control involuntary movements.
Autonomic System • Two divisions: • sympathetic • Parasympatheitic • Control involuntary functions • heartbeat • blood pressure • respiration • perspiration • digestion • Can be influenced by thought and emotion
The brain can be divided into 3 regions • medulla • Cerebellum • Cerebrum
Cerebrum -is the thinking part of the brain and it controls your voluntary muscles.
Cerebellum -It controls balance, movement, and coordination (how your muscles work together).
Medulla -is to control your involuntary muscles the ones that work automatically, without you even thinking about it, also sorts through the millions of messages that the brain and the rest of the body send back and forth.
Brain Spinal Cord Nerves Peripheral Nervous System • 2 kinds of neurons connect CNS to the body • sensory • motor
Motor - CNS to muscles and organs: a nerve cell neuron that sends nerve impulses from the spinal cord or brainstem away from the central nervous system toward a muscle or gland • Sensory - sends nerve impulses from the sense organs (sensory receptors) to the CNS.
Brain Sensory Neuron Motor Neuron Skin receptors Interneuron Muscle
The senses provide information about the outside environment to the nervous system. There are five senses: • Sight • Touch • Hearing • Taste • Smell
5 senses • The senses of sight, touch and hearing involve processing physical information from the environment. • The senses of smell and taste involve processing chemical information.
5 senses • Let’s look each one and explore the nerve responsible for helping navigate our world.
Optic nerve • Optic nerve- the second pair of cranial nerves whose nerve fibers transmit visual light signals from the eye to the brain.
Auditory nerve • Auditory nerve-nerve connecting inner ear to brain: a nerve that conveys impulses relating to hearing and balance from the inner ear to the brain
Olfactory nerve • Olfactory nerve- nerves consisting of sensory fibers that conduct to the brain the impulses from the mucous membranes of the nose.
taste • Taste buds-Oval-shaped clusters of cells located on the tongue and lining of the mouth that contain special nerve endings that help give rise to the sense of taste.
skin • Is made up of different layers. Let’s look at 2 of them. • Dermis • Epidermis
Dermis • Dermis -the dense inner layer of skin beneath the epidermis, composed of connective tissue, blood and lymph vessels, sweat glands, hair follicles, and an elaborate sensory nerve network.
Epidermis • Epidermis-the outer layer of the skin covering the exterior body surface of vertebrates.
Light to Dark • There are many different skin tones. From the very light to the very dark. Let’s look at what causes us to have different skin color.
Melanin • Melanin-Insoluble naturally occurring dark pigments found in skin, hair, fur, and feathers. Responsible for the color of your skin. • Melanin protects the body by absorbing ultraviolet radiation from the sun.
