Nervous System Flashcards
Multipolar Neurons
Motor & CNS
Unipolar Neurons
Sensory (PNS)
Bipolar
special senses (eyes)
Function of nervous system
transmits signals between the brain and the rest of the body, including internal organs
Organs of nervous system
Nerves, brain, spinal cord
Which cells of the nervous system send and receive signals?
Neurons
synapse
Site of communication between neuron and target cell
What type of substances can cross the cell membrane and how do they cross the cell
membrane?
Diffusion and exostosis and endotosis
When is a neuron resting and generating the resting membrane potential?
When it is not sending or receiving signals
Where are chemically gated channels located?
on the dendrites and cell body of the neuron.
Where are the voltage-gated channels located?
on the axon hillock, all along unmyelinated axons, and at the nodes of Ranvier in myelinated axons.
function of Cerebrospinal fluid
It gives buoyancy to the CNS structures, protecting them from trauma as well as nourishing the brain and carrying chemical signals.
Refractory period
an action potential is in progress, another one cannot be initiated.
absolute refractory period
another action potential will not start. This is because of the inactivation gate of the voltage-gated Na+ channel. Once the Na+ channel is back to its resting conformation, a new action potential could be started during the hyperpolarization phase, but only by a stronger stimulus than the one that initiated the current action potential.
continuous conduction
Propagation along an unmyelinated axon
saltatory conduction
propagation along the length of a myelinated axon
neuropeptide
a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein
Biogenic amines
a group of neurotransmitters that are enzymatically made from amino acids.
metabotropic receptor
involves a complex of proteins that result in metabolic changes within the cell.
effector protein
an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.
graded potentials
Local changes in the membrane potential away from resting levels
excitatory postsynaptic potential (epsp)
Depolarization in a postsynaptic potential
inhibitory postsynaptic potential (IPSP)
Hyperpolarization in a postsynaptic potential
Depolarization
Increase in membrane potential (due to Na+ voltage gated channels opening)
Repolarization
Decrease in membrane potential (due to K+ voltage gated channels opening)
Hyperpolarization
Further decrease in membrane potential past resting membrane potential (due to K+ voltage gated channels remaining being opened)
Trigger zone
The first section of an axon capable of producing an action potential. Contains many voltage gated sodium and voltage gated potassium channels
What factors affect the velocity of an action potential?
Diameter of the axon, whether axon is myelinated, temperature
stroke
Loss of bloodflow to part of the brain
ischemic stroke
the loss of blood flow to an area because vessels are blocked or narrowed
hemorrhagic stroke
bleeding into the brain because of a damaged blood vessel.
basal nuclei
responsible for cognitive processing, the most important function being that associated with planning movements
basal forebrain
contains nuclei that are important in learning and memory
limbic cortex
the region of the cerebral cortex that is part of the limbic system, a collection of structures involved in emotion, memory, and behavior.
thalamus
a collection of nuclei that relay information between the cerebral cortex and the periphery, spinal cord, or brain stem
hypothalamus
a collection of nuclei that are largely involved in regulating homeostasis.
hypothalamus
a collection of nuclei that are largely involved in regulating homeostasis.
What protects the brain?
Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.
What is the difference between white matter and gray matter?
White matter: axons or neurons
Grey matter: cell bodies
Where must information reach for complete, conscious awareness?
the cerebral cortex
diencephalon function
primary relay and processing center for sensory information and autonomic control
There are two cerebral hemispheres – what separates them?
a longitudinal fissure
What is the cerebral cortex
Outer layer of brain, gray matter
red: primary motor cortex, motor association area
orange: primary somatosensory area, sensory association area
yellow: primary visual area and visual association area
green: primary auditory area, auditory association area
What cells make CSF?
ependymal cells
What is the blood-brain barrier and why does it exist?
a structural and functional roadblock to microorganisms, such as bacteria, fungi, viruses or parasites, that may be circulating in the bloodstream
What is the major function of the thalamus?
All information from your body’s senses (except smell) must be processed through your thalamus before being sent to your brain’s cerebral cortex for interpretation. Your thalamus also plays a role in sleep, wakefulness, consciousness, learning and memory
What are some very important functions of the hypothalamus?
helps manage your body temperature, hunger and thirst, mood, sex drive, blood pressure and sleep, homeostasis
broca’s area (frontal lobe)
responsible for the production of language, or controlling movements responsible for speech;
Wernicke’s area
comprehension of speech.
aphasia
a disorder that affects how you comunicate
association fibers
same hemisphere
commisural fibers
connect an area in one hemisphere with an area in the opposite hemisphere.
projection fibers
connects the cortex with other areas in the CNS
conus medullaris
end of spinal cord
cauda equina
The nerves that extend down from the spinal cord
what anchors the conus medullaris to the coccyx
filum terminale
astrocytes
maintaining the concentration of chemicals in the extracellular space, removing excess neurotransmitters, reacting to tissue damage, and inducing to the blood-brain barrier (BBB).
oligodentrocytes
wraps myelin arms around many axons in CNS
schwann cells
one cell wraps itself around axon creating myelin sheath (PNS)
microglia
defend brain from invaders
ependymal cells
CSF homeostasis, brain metabolism, clearance of waste, make CSF
satellite cells
maintain extracellular environment, remove neurotransmitter, direct neural growth (PNS)
How many pairs of spinal nerves are in humans?
31
Through which vertebral structures do spinal nerves emerge?
posterior (doral) horn ,anterior (ventral) horn,
Lateral horn
autonomic motor neurons
ventral root
somatic motor neurons
dorsal root
sensory neurons
What happens to spinal nerves/neurons when they enter a plexus?
nerve fibers from different spinal nerves are sorted and recombined, so that all fibers going to a specific body part are put together in one nerve.
