Exam 2 Nervous System Flashcards
Nervous vs Endocrine
Nervous system responds faster, within milliseconds.
Endocrine system is slower, within min, hrs, or days.
Nerve cells
Neurons specialized to transmit impulses.
Excitability
Ability to respond to a stimulus.
Conductivity
Ability to transmit a signal.
Neuroglia
Specialized cell that supports the neurons in some way.
Central Nervous System
Consists of brain and spinal cord, surrounded by skull and vertebral column. Central control of body.
Peripheral Nervous System
All neural tissue outside of CNS. Divided into somatic and automatic.
Somatic Nervous System (SNS)
Composed of somatic afferent and somatic efferent divisions.
Somatic Afferent (sensory) Division
Input. Receives sensory information and conveys it to spinal cord and brain, via nerves.
Somatic Efferent (motor) division.
Output. Regulates contraction of skeletal muscles via neural pathways. Descends from brain and spinal cord to lower motor neurons.
Autonomic Nervous System (ANS)
Regulates internal organs. Has sensory neurons (viscera -> CNS) and motor neurons (CNS-> smooth muscle, glands, etc)
Sympathetic division
Speeds the heartbeat. Fight or flight. Involve expenditure of energy.
Parasympathetic division
Neurons that would slow the heartbeat. Neurons that restore and conserve body energy.
Nervous System
One of the major regulatory systems.
In charge of homeostasis.
Neurons
Very specialized functional unit.
Has cell body, dendrites, and an axon.
Cell body
Large nucleus, with nucleolus, and several structures responsible for metabolism, growth, and repair of neurons.
ER, mito, golgi, lyso, neurofilaments, neurotubules.
Neurotubules
Function in the intracellular transport of proteins and other substances. In both directions between cell body and ends of processes.
Neurofilaments
Skeletal framework for the axon.
Dendrites
Thread like extensions of the cell body. Conduct nerve impulses towards the cell body.
Axons
Originates from axon hillock. Carries nerve impulses away from the cell body to the next neuron.
Initial segment
Where the action potential begins. Lies immediately after the axon hillock.
Collateral branchess
Side processes of Axons.
Telodendria
Small axon branches, end in tiny swellings called end bulbs.
Synapse
Chemical and electrical synapse. Junction between end bulb of one axon and the cell body, dendrite, axon of another neuron. Site where info is being transferred.
Myelination of Axons
Axons are covered with layers of a lipid sheath called myelin.
Neurolemmocyte (Schwann cells)
Form myelin sheaths around axons in PNS.
Oligodendrocyte
Form myelin sheaths in the CNS.
Neurilemma sheath
The outer layer of sheath.
Nodes of Ranvier
The gap that interrupts at regular intervals and segments the myelin sheath.
Internode
Distance from one node to the next.
Myelinated axon
Axon that has a myelin sheath.
Unmyelinated axon
Axon that has no myelin sheath.
Multipolar Neurons
Has many processes consisting of many dendrites and 1 axon.
Bipolar Neurons
Has two processes: a dendrite and an axon which conducts action potentials to the CNS.
Unipolar Neurons
Have 1 process, an axon.
Interneurons (association) neurons
Lie between sensory and motor neurons in the neural pathways of the CNS.
