Nervous system
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34 terms
Terms | Definitions |
|---|---|
 resting potential | electrical charge across the cell membrane of a neuron |
| threshold | minimum level of stimulus needed to activate a neuron |
| action potential | reversal of charges across the cell membrane of a neuron as an impulse passes |
| brain stem | connects brain to the spinal chord; controls information going in and out of the brain; controls involuntary actions |
| thalamus | recieves messages from sensory receptors and relays to proper part of cerebrum |
| spinal chord | controls reflexes; carries signals from brain to the rest of the body |
| sensory division of peripheral nervous system | transmits impulses from sensory neurons to CNS |
| motor division of the peripheral nervous system | transmits impulses from CNS to muscles and glands |
| somatic nervous system | part of motor division; regulates voluntary activities |
| autonomic nervous system | part of motor division; regulates involuntary activities |
| impulse | the electrical discharge that travels along a nerve fiber |
| hormones | chemical "messengers" of the endocrine system that are released into the blood |
| protein hormones | class of hormones that cannot pass through the cell membrane; less likely to be stored in the body |
| steroid hormones | class of hormones that can pass through the cell membrane; can be stored in the body |
| prostaglandins | local hormones that do not enter the bloodstream |
| positive feedback | Process that amplifies a small change (Reinforce change) |
| negative feedback | a response that opposes the original stimulus |
| acetylcholine | Neurotransmitter chemical released at the ends of some nerve cells |
| motor nerves | Carry messages away from the brain and spinal cord to muscles and organs |
| sensory neurons | type of neurons that usually has long dendrites and short axons, and carry messages from the body to the CNS |
| motor neurons | usually has long axons and short dendrites, and transmits messages from the central nervous system to the body |
| interneurons | found only in the CNS where they connect neuron to neuron and gives quick responses |
| saltatory conduction | process of impulses jumping from node to node |
| sodium potassium pump | maintains unequal concentration by actively transporting ions against concentration gradients |
| stimulant | makes membrane more permeable to sodium and increases synaptic transmission of impulses in brain (eg. caffeine, cocaine, mescaline, nicotine) |
| depressants | inhibit an impulse at synapse (eg. anesthetics, botulin, curare, serotonin) |
| psychedelic drug | affects role of serotonin and alter perception (eg. LSD, marijuana) |
| analgesics | they relieve pain by interfering with transmission of pain impulses to cerebral cortex. |
| cerebral cortex | controls intelligence, reasoning, learning, memory |
| hypothalamus | regulates homeostasis, links nervous system to endocrine system |
| cerebellum | controls muscles, posture, balance, causes continuous state of muscle contraction |
| medulla oblongata | involved with regulation of heartbeat, breathing, vasoconstriction, reflex |
| cranial nerves | takes impulses to and from CNS (in PNS) |
| spinal nerves | takes impulses to and away from spinal chord |
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