chapter 9 Flashcards
what part of the body is part of the central nervous system
the brain and spinal cord only!!!
This part of the nervous system is responsible for transmitting to the brain input from the somatic and special sensory receptors and somatic sensory neurons, touch pressure temperature etc… it is voluntary and the brains response is through the somatic motor neurons that send messages to the skeletal muscles.
SNS Somatic Nervous System
This part of the nervous system is responsible for transmitting to the brain input from the autonomic sensory receptors and autonomic (automatic) sensory neurons (internal organs, blood vessels, and glands) such as fluctuations in blood pressure, oxygen, etc… it is non-voluntary and the brains response is to the autonomic motor neurons sympathetic and parasympathetic (internal organs, blood vessels, and glands) divisions send messages to smooth muscle, cardiac muscle, and glands.
ANS Autonomic Nervous System
This part of the nervous system gets no direct output from the CNS It is mostly it’s own system in which the enteric sensory receptors and enteric sensory neurons in the GI tract and enteric plexuses send messages to the brain and to the enteric motor neurons in the enteric plexuses which in turn send messages to the smooth muscles, glands, and endocrine cells of the GI tract all involuntarily - it also receives some input from the ANS.
ENS - Enteric Nervous System
The SNS, ANS, and ENS are all part of what nervous system?
the PNS - Peripheral Nervous System - which controls all nervous tissue outside the CNS
what are the three functions of the nervous system?
sensation
integration
motor function - effectors
detecting internal and external stimuli and transmitting information to the CNS such as touch a hot pan or a rise in blood pressure falls under what function of the nervous system
sensation
this function of the nervous system analyses sensory information and makes decisions for appropriate responses
integration
this function of the nervous system is carried out when effectors are activated by nerves to contract a muscle or activate a gland
motor function
the main cell of the nervous system
neuron
arms coming off of the neuron that receive action potentials from other neurons
dendrites
signals come into this part of the neuron
the cell body
longer extension or arm (usually only one) that transmits signals away from the cell body
axon
the ends of an axon release chemical signals called ______ that tell the next cell what it should do
neurotransmitters
this classification of neurons carries information toward the CNS; each one is connected to specialized receptors which each detect a different kind of stimulus
sensory neuron
This classification of neurons carries information away from the CNS, going towards a receptor, synapses with a muscle or a gland
motor neuron
This classification of neurons is located between sensory and motor neurons and are found only in the CNS.
Interneurons
what are the three classifications of neurons
sensory
motor
interneurons
these special cells in the CNS help neurons communicate effectively
neuroglial cells
what are the five types of neuroglial cells (another monkey eats olives)
astrocytes
microglia
ependymal cells
oligodendrocytes
these neuroglial cells support neurons and maintain proper chemical environment
astrocytes
these neuroglial cells are immune cells
microglia
these neuroglial cells produce and circulate cerebrospinal fluid (csf) - line cavities in the brain
ependymal cells
these neuroglial cells produce myelin sheath in CNS
oligodendrocytes
these neuroglial cells produce myelin sheath in PNS
Schwann cells
This insulating outer layer is created by Schwann cells (PNS) and oligodendrocytes (CNS) and allows action potential to “jump” quickly down the axon - wraps around the axon and makes communication from the brain move faster
myelin sheath
the gaps in the myelin sheath that the action potential jumps between down the axon
nodes of ranvier
produces myelin sheath in CNS by processes of one cell producing myelin sheath on many axons
oligodendrocytes
produces myelin sheath in PNS by one cell wraps around the axon many times
Schwann cells
this nervous tissue is composed mostly of cell bodies and also axons with no myelin (myelin is white)
grey matter
this nervous tissue is composed mostly of myelinated axons
white matter
neurons communicate with each other and the body’s other components through electrical impulses used to communicate from one cell to the next - called ?
action potentials
during the action potential what happens to the charge on the inside and the outside of the axon?
it flips
what is the charge in a resting neuron
the inside is negative and the outside is positive so no signal is being transmitted at this time
what is the unequal distribution of charges on the inside and outside of the cell called
polarized
what is used to create the flip in the charge of the neuron?
two very important ions:
sodium Na+ and potassium K+
describe the 4 steps involved in the action potential
1) THRESHOLD is met - there is a minimum amount of stimulus that must be met to cause the reaction - the stimulus must be strong enough to cause a response in the neuron. once this happens there is no going back it is all or nothing.
2) DEPOLARIZATION - the inside of the cell becomes more positive which is caused by the flow of sodium (NA+) ions into the cell.
3) REPOLARIZATION - the inside of the cell returns towards the original state which is caused by the flow of potassium (K+) ions out of the cell.
4) HYPERPOLARIZATION - the cell becomes too negative and no action potentials can be generated this is intentional so that the flow of the action potential continues forward along the axon and does not move backwards.