Central Nervous System Brain + spinal cord. Oversees everything we do, feel and think
Peripheral Nervous System Relays messages to and from outer parts of the body (periphery) and the brain. Sensory nerves collect information from the senses. Motor nerves control the muscles. (pg 289. 9.3)
Autonomic nervous system the part of the nervous system outside conscious control affects the cardiovascular, digestive, reproductive and respiratory organs. sympathetic parasympathetic (fight/flight) (restores calm) (Pg 289 activity 9.4)
Nerves Nerves Collections of neurons that are joined together by connective tissue. Responsible for transferring impulses from receptors to CNS and back to effectors (muscles or glands).
The Neuron the basic functional unit of the nervous system. is a cell that processes and transmits information by electrochemical signaling You have around 100 billion neurons
Basic Neuron Structure
Dendrite extensions that receive information from other neurons Cell Body or Soma The control center of the neuron, contains nucleus Axon transmits infomation from dendrites to other neurons Myelin Sheath An insulating layer around an axon.
Types of Neurons 1. Sensory Neurons Neurons located in receptororgans (skin, eyes, ears). Function: receive incoming stimuli from the environment. 2. Motor Neurons Neurons located near effectors (muscles and glands) Function: Carry impulses to initiate a response. 3. Interneurons Neurons that relay messages between other neurons eg between sensory and motor neurons. (found most often in brain and spinal cord).
Communication within neurons is electrical An electrical signal is sent down the length of the axon. This electrical signal is called an “action potential”
Communication between neurons is chemical When the electrical impulse reaches the terminal buttons, they release chemicals called neurotransmitters(NTs) into the synapse.
Communication between neurons is chemical These NTs connect with receptor sites of nearby neurons. The neurotransmitters “fit in” to these receptor sites like a key into a lock.
Neurotransmitters… …are chemicals that are released into the synapse by neurons. These NTs are “taken back up” into the terminal buttons of neurons through the process of reuptake
How anxiety effects the body
Excitoryvs Inhibitory neurotransmitters Depending on the neurotransmitter released into the synapse it either excites or inhibits the next neuron from firing. Some neurotransmitters do both!
Drugs Interfere with Neurotransmission Drugs can affect synapses at a variety of sites and in a variety of ways, including: Increasing number of impulses Release neurotransmitters from vesicles with or without impulses Block reuptake or block receptors Produce more or less neurotransmitters Prevent vesicles from releasing neurotransmitters
Drugs That Influence Neurotransmitters
Electroencephalograph (EEG) machine designed to record the brain wave patterns produced by electrical activity of the surface of the brain.
Computed tomography (CT) brain-imaging method using computer controlled X-rays of the brain.
Magnetic resonance imaging (MRI)
brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain.
Functional Magnetic resonance imaging (fMRI)
Functional MRI (fMRI) – computer makes a sort of “movie” of changes in the activity of the brain using images from different time periods.
Positron emission tomography (PET) brain-imaging method in which a radioactive sugar is injected into the subject and a computer compiles a color-coded image of the activity of the brain with lighter colors indicating more activity.
Brain Plasticity Neuroplasticity or brain plasticity refers to the brain’s ability to CHANGE throughout life. The brain has the amazing ability to reorganise itself by forming new connections between neurons.