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Nervous System. Mr. Gagnon. How the Nervous System Works. Key Questions: What are the functions of the nervous system? What are the 3 types of neurons and how do they interact? Key Terms: Stimulus Response Neuron Nerve Impulse Dendrite Axon Nerve Sensory Neuron
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Nervous System Mr. Gagnon
How the Nervous System Works Key Questions: What are the functions of the nervous system? What are the 3 types of neurons and how do they interact? Key Terms: Stimulus Response Neuron Nerve Impulse Dendrite Axon Nerve Sensory Neuron Interneuron Motor Neuron Synapse
Jobs of the Nervous System Receiving Information Responding to Information • Awareness of what is around you. • Senses and sensory cells help map out surroundings. • A response is created for what you sense. • Duck!!!!
Neuron (Nerve Cell) Dendrites- Are where a cell receives a chemical signal. The “receptor” of chemical signals. Nucleus- The Brain of the cell. Cell Body- The body of the cell. Axon- An arm like figure that sends an electric signal to the synapse. Synapse- Where chemicals are released from the neuron into intercellular space. Nerve Impulse- The Neuron signal. Nerve- Is a bundle of axons and dendrites.
Different Kinds of Neurons Interneuron Sensory Neuron • Sends an impulse to a muscle, and the muscle contracts in response. • Is a neuron that carries nerve impulses from one neuron to another. • Pick up stimuli from the internal or external environment and converts it into a nerve impulse. Motor Neuron
Divisions of the Nervous System Key Questions: What is the function of the central nervous system? What functions does the peripheral nervous system perform? What is a reflex? Key Terms: Central nervous system Brain Spinal Cord Cerebrum Brainstem Somatic Nervous System Autonomic Nervous system Reflex Concussion
Central Nervous System • The “control center” of the body. • Contains the brain and spinal cord. • The peripheral nervous system consists of the nerves located outside of the central nervous system. Two-way traffic • The Brain, located in the skull and controls most functions of the body’s functions. • The spinal cord, is the thick column of nerve tissue that links the brain to most of the nerves in the peripheral nervous system.
Central Nervous System (CNS) • Consists of the brain and spinal cord. • The brain and spinal cord are surrounded by a fluid called cerebral spinal fluid (CSF). • No blood comes directly into contact with the brain or the spinal cord.
Peripheral Nervous System (PNS) • The PNS extends from the CNS to various parts of the body. • The PNS sends messages to the CNS (sensory) as well as receives messages from the CNS(motor).
Controlling Your Nervous System • Somatic Nervous System- This system controls your voluntary movements (tying shoelaces, throwing a ball). • Autonomic Nervous System- This system controls automatic functions like breathing. • Reflexes- an automatic response that occurs very rapidly and without conscious control (blinking, knee-jerk).
Brain Anatomy Website: Brain Interactive
Senses Key Questions: What overall function do the sense perform? How do your eyes enable you to see? How do you hear? Key Terms: Cornea Pupil Iris Lens Retina Nearsightedness Farsightedness Eardrum Cochlea Semicircular Canal
VISION • Vision is controlled by the eye and eye muscles. • The eye responds to light, dilating in dark rooms and contracting in well lit rooms.
Key Terms: Lens- Focuses light onto the retina. Iris- Circular structure that surrounds the pupil and regulates the amount of light entering the eye. Cornea- Clear tissue that covers the front of the eye. Pupil- The opening through which light enters the eye. Aqueous Humor- Liquid in the front of the eye. Vitreous Humor- Liquid in the body of the eye. The Eye
Key Terms: Conjunctiva- Mucous membrane covering the eyeball. Sclera- Fibrous outer layer of the eyeball. Retina- The layer of receptor cells that line the back of the eye. (Rods 120 million black and white. Cones 6 – 7 million color) Macula (Fovea centralis)- Where the light focuses on. Optic Nerve- Relays messages from the eye to the brain. The Eye Cont.
Vision Lab Check your blind spot. Does your vision vary from others? Click Here Reflections: 1. Circle and Plus Sign 2. Bar Code and Plus Sign 3. Moving Red Dot and Plus Sign 4. Peripheral Marker Test
Hearing • Sounds starts as a vibration (guitar string, vocal cord, etc.). • The vibration creates waves (sound waves). • The ear receives sound vibrations.
The Ear Key Terms: Ear Canal- Funnels sound into the ear. Eardrum- Vibrates in response to sound. Separates middle and outer ear. Hammer (Malleus)- Vibrations pass from the eardrum to this bone. Anvil (Incus)- Vibrations pass from the hammer to this bone. Stirrup (Stapes)- Vibrations pass from the anvil to this bone.
The Ear Key Terms: Semicircular Canals- Contains receptors to help with balance. Cochlea- Bony, snail shaped tube that is lines with receptor to respond to sound. Auditory Nerve- Conducts impulses to the brainstem.
Smell • Odors get trapped in the nasal mucous. • Receptor cells have cilia (hair-like structures) that send signals to the brain. • The brain then deciphers what the scent is.
Taste • Taste buds along with the salivary glands help with taste, however they do not work alone. • The olfactory system helps with the sense of taste.
Touch • The skin has many types of receptors, light pressure and heavy pressure, temperature, and pain receptors. • All of these receptors use the peripheral nervous system to relay the information to the central nervous system.