Chapter 26: Coordination by Neural Signaling
The 2 parts of the Central Nervous System and what is the function of each. Brain: sensory fibers, somatic sensory, visceral sensory; Spinal Cord: motor fibers, somatic motor fibers, autonomic motor fibers, sympathetic division, parasympathetic division.
The main parts of the brain and what each does.
Structure and function of the neuron: be able to label it. Neurons are specialized to conduct nerve impulses and those allow sensory info to reach CNS and nerve impulses allow CNS to send out motor directives in nerve fibers. 527
Know the different types of neurons and how they function in the nervous system. Motor: carry nerve impulses from CNS to muscles or glands; sensory neurons: take nerve impulses from sensory receptors to CNS; Interneurons: parallel the structure of motor neurons and their axons conduct nerve impulses between various parts of the CNS.
What is an “action potential”, how does it work? A rapid change in polarity across an axon membrane as the nerve impulse occurs. If a stimulus causes the axon membrane to depolarize to a certain level, called threshold, an action potential occurs in an all or none manner. The gates of sodium channels open, and sodium flows into the axon. As sodium moves to the inside of the axon, the membrane potential changes from -65mV to +40mV. This is depolarization. The reversal in polarity causes the sodium channels to close and potassium to open. 528
What are neurotransmitters? How do they work? Name specific neurotransmitters and what they do. Chemical stored at the ends of axons that is responsible for transmission across a synapse. 3 steps: 1-Nerve impulses traveling along axon reach axon terminal , gated channels for calcium ions open and enter the terminal. 2-Neurotransmitter molecules are released into the synaptic cleft and they diffuse across the cleft to the postsynaptic membrane. 3-They bind with specific receptor proteins. Ach and NE-Associated with Alzheimers, ACh has either excitatory or inhibitory effect on smooth muscle and glands. Serotonin- involved in thermoregulation, sleeping, emotions, and perception. Dopamine and GABA- Dopamine is involved with emotions, control of motor function, and attention. Endorphins-block the release of substance P and is considered a natural painkiller. Chart on 542
How does caffeine, heroin, marijuana, meth, alcohol, cocaine, ecstasy effect the CNS? Caffeine- helps keep a person awake by interfering with the effects of inhibitory neurotransmitters in the brain; Heroin-travels rapidly to the brain where it is converted to morphine which brings a rush of euphoria. Marijuana- Person experiences mild euphoria along with alterations in vision and judgment; Meth-stimulant, it reverses the effects of fatigue, maintains wakefulness and temporarily elevates mood; Alcohol-depressant, increases the action of GABA, which inhibits motor neurons and increases the release of endorphins; Cocaine-stimulant, interferes with the re-uptake of dopamine at synapses; ectasy-has an overstimulatory effect on neurons that produce serotonin to elevate mood.
What are the meninges? Where are they found? What is their function? Protective membranous coverings about the CNS(brain and spinal cord.) 534
Be able to label: the brain~~structure and function 536 Spinal Cord-center for many reflex actions and it provides a means of communication between brain and spinal nerves; brain ventricles- four of them, 2 lateral are inside the cerebrum, 3rd is surrounded by diencephalon, and 4th lies between cerebellum and the pons. Cerebrospinal fluid is continuously produced in the ventricles and circulates through them and flows out between the meninges; cerebrum-largest portion of the brain for humans, last center to receive sensory input and carry out integration before commanding voluntary motor responses, divided…