Chapters 3.2 Flashcards
Neurons
One of the major cells found in the nerves system, that are responsible for sending and receiving messages throughout the body.
cell body
(or soma) the part of the neurone that contains the nucleus.
dendrites
small branches radiating from the cell that receive messages from other cells and transmit those messages towards the rest of the cell.
axon hillock
located at the base of the cell body. if the hillock receives enough stimulation, it will stimulate a chemical reaction.
axon
a tail like structure that transports information in the form of electrochemical reactions from the cell body to the end of the neurone.
axon terminal
bulb like extensions filled with vesicles at the end of the axon.
neurotransmitters
found in vesicles. are the chemicals that function as messengers allowing neurones to communicate with each other.
sensory neurons
receive information from the body senses and bring it TOWARD the brain.
motor neurons
carry messages AWAY from the brain and spinal cord towards muscles
glial cells
specialized cells of the nervous system that are involved in mounting immune responses in the brain, removing waste, and synching neutron activity
myelin sheath
a white fatty substance produced by certain glial cells, that increases speed and efficiency in neural communications.
multiple sclerosis
is a disease where the immune system does not recognize myelin and attacks it. which can devastate the functional integrity of the nervous system.
Neural activity
based on changes in the concentrations of ions. when a neurone is not transmitting information, the outside has a high concentration of positive ions, while the inside has a negative concentration.
Resting potential
the relatively stable state(-70mv) during which the cell is not transmitting messages.
electrostatic gradient
inside and outside of the cell have different charges.
concentration gradient
different types of ions are more densely packed on one side
ion channel
When a neuron is stimulated, and ion channels open up, the influx of positive ions in the cell causes the potential to change to -68mV. If enough of these positive ions reach the axon hillock and push its charge past its threshold (eg. -55mV), the neuron will activate.
action potential
a wave of electrical activity that originates at the base of the axon and rapidly travels down its length. charge reaches +35mv at the specific point.
hyper polarized
once the positive ions are pumped out of the axon, the charge becomes more negative than usual. (-72mv)
refractory period
the brief 3-3ms period where the neurone cannot fire.
synapses
the microscopically small spaces that separate individual nerve cells and receive the neurotransmitters.
presynaptic cells
the cells that release neurotransmitters
postsynaptic cells
the part that receives the neurotransmitters.
all-or-none principle
individual nerve cells fire at the same strength every time an action potential occurs.
excitatory neurotransmitter
increases the probability of the neurone firing by increasing the charge from -70mv to -68mv.
inhibitory neurotransmitter
decreases the probability of it firing by decreasing its charge from -70mv to -72mv
synaptic cleft
the minute space between the axon terminal and dendrite where discarded neurotransmitters are released
re-uptake
neurotransmitters are either broken down by enzymes or go through reuptake, where they are reabsorbed into the axon terminals of the presynaptic neurone.
glutamate
the most common excitatory neurotransmitter in the brains of invertebrates. also involved in process of forming new memories.
GABA (gamma-amino butyric acid)
is the primary inhibitory neurotransmitter of the nervous system.
Acetylcholine
is one of the most win spread neurotransmitters within the body, found at the functions between nerve cells and skeletal muscles. very important for voluntary movement.
neuromuscular junction
the link between our nervous system and our muscles.
monoamines
class of neurotransmitter which includes: dopamine, norepinephrine, and serotonin
dopamine
is involved in varied functions, like mood, control of voluntary movement and processing of rewarding experiences.
norepinephrine
is involved in regulating stress responses, including increasing arousal, attention, and heart rate; it is also sent down the spine when involved with the fight-or-flight response. regulates wakefulness and attention.
serotonin
is involved in regulating sleep, mood, aggression, and appetite
agonists
are drugs that enhance or mimic the effects of a neurotransmitters actions.
direct agonist
physically binds to that neurotransmitters receptor on the postsynaptic cell.
indirect agonist
facilitates the effects of a neurotransmitter, but does not physically bind to the same receptor as the neurotransmitter.
antagonists
inhibit neurotransmitter activity by blocking receptors or preventing synthesis of a neurotransmitter.
direct antagonists
physically blocks the neurotransmitter receptor.
indirect antagonist
reduces the effects of neurotransmitters without physically blocking receptors.
hormones
are chemicals secreted by the glands of the endocrine system
homeostasis
the balance of energy, metabolism, body temperature, and other basic functions that keep the body working properly.
hypothalamus
the brain structure that regulates basic biological needs . releases specialized chemicals called releasing factors that stimulate the pituitary gland
pituitary gland
the master gland of the endocrine system that produces hormones that sends commands about hormone production to the other glands of the endocrine system.
adrenal gland
a pair of endocrine glands located adjacent to the kidneys that release stress hormones.
endorphin
a hormone produced by the pituitary gland and the hypothalamus that functions to reduce pain and induce feelings of pleasure
