INTRO--MODULE 1

Dorsal View: view of the human brain from the top Ventral View: view from the bottom

receives information and transmit it to other cells

86 B on an average

• it is the surface of a cell • most chemicals cannot cross the membrane, but protein channels in the membrane permit a controlled flow of water, oxygen, sodium, potassium, calcium, chloride, and other important chemicals

nucleus

• the structure that performs metabolic activities, providing the energy that the cell uses for all activities • They have genes separate from those in the nucleus of a cell, and mitochondria differ from one another genetically

sites within the cell that synthesize new protein molecules

proteins provide building materials for the cell and facilitate chemical reactions

• while some ribosomes float freely, some are attached here • a network of thin tubes that transport newly synthesized proteins to other locations • tail part of neurons

• sensory input • integration • motor output

• Central nervous system: consists of brain and spinal chord • Peripheral nervous system: composed of all the nerves that branch off from the brain and spine (allows CNS to communicate with the rest of your body) Sensory division (afferent) Motor division (efferent) Somatic nervous system (voluntary): rules your skeletal muscle movement Autonomic nervous system (involuntary): keeps your heart beating, lungs breathing, stomach churning Sympathetic division: mobilizes body into action Parasympathetic division: relaxes the body

soma, dendrites, axon, presynaptic terminals

with its soma in the spinal cord, receives excitation through its dendrites and conducts impulses along its axon to a muscle

specialized at one end to be highly sensitive to a particular stimulation, such as light, sound, or touch

• branching fibers that get narrower near their ends • The dendrites surface is lined with specialized synaptic receptors, at which the dendrite receives information from other neurons • The greater the dendritic surface, the more information it can receive

short outgrowths that increase the surface area available for synapses

contains the nucleus, ribosomes, and mitochondria; most of the neuron’s metabolic work occur here

thin fiber of constant diameter; conveys an impulse toward other neurons, an organ, or a muscle

• insulating material in vertebrate axons with interruptions known as nodes of ranvier • invertebrate axons do not have myelin sheaths

dendrites; axon

• a swelling at the end of each branch; aka end bulb or bouton • at that point the axon releases chemicals that cross through the junction between that neuron and another cell

afferent axon: brings information into a structure; picks up sensory input efferent axon: carries information away from a structure; sends directions from your brain to muscles and glands interneuron/intrinsic/association neuron: if a cell’s dendrites and axon are entirely contained within a single structure. transmits impulses between sensory and motor neurons

sensory; motor

• wrap around the synapses of functionally related axons • by surrounding a connection between neurons, enabling their axons to send messages in waves • important for generating rhythms, such as the rhythm of breathing • dilates the blood vessels to bring more nutrients into brain areas that have heightened activity • tripartite synapse: the tip of an axon releases chemicals that cause the neighboring astrocyte to release chemicals of its own, thus modifying the message to the next neuron • also responds to hormones and thereby influence neurons