THE NERVOUS SYSTEM Flashcards
components of the central nervous system
brain and spinal cord
components of the peripheral nervous system
Nerves outside the CNS Nerves extending to & from the brain and spinal cord
the three main functions of the nervous system(brief description)
Sensory: Afferent neurons transmit sensory information
Processing: CNS processes incoming sensory information & responds
Motor: Efferent neurons transmit motor signals
the two parts of sensory nervous system
somatic and visceral
somatic sensory nervous system
This system is associated with the conscious(voluntary) perception of sensory information from the external environment and the body.
visceral sensory nervous system
The visceral sensory system, also known as the internal or autonomic sensory system, deals with sensory information from the internal organs (viscera), such as the heart, lungs, stomach, and intestines.
the two parts of sensory nervous system
somatic and visceral
somatic motor nervous system
The somatic motor system controls voluntary movements of skeletal muscle
visceral motor nervous system
The autonomic motor system, often referred to simply as the autonomic nervous system (ANS), controls involuntary functions and regulates internal organs, glands, and smooth muscles.
the functional unit of the nervous system
neurons
key features or properties of neurons
longevity
do not divide
high metabolic rate
why do neurons stay the same for a long time (longevity)
they lose their mitotic ability after differentiation
The stability of neurons is critical for memory and learning processes
chromatophilic bodies
Clusters of rough ER and ribosomes
ganglia
clusters of cell bodies in PNS
general components of a typical neuron
cell bodies
myelin sheath
nodes of Ranvier
Schwann cells
Dendrites
axon
axon terminals
function of dendrites
Transmit electrical signals toward the cell body
function of axon
Transmits action potentials away from cell body
how many axons does each neuron have
one, but they can branch
synapse
the region where an axon terminal communicates with it’s post synaptic target neuron
classes of neurons
bipolar
Pseudounipolar
multipolar
unipolar
features of Pseudounipolar neurons
they have a single axon
it’s axon branches to connect to the CNS neurons
what type of neurons are Pseudounipolar neurons found as
Sensory neurons
features of a bipolar neuron
single axon
single dendrite
they are rare
which type of neurons are bipolar neurons found as
sensory neurons
features of multipolar neurons
multiple dendrites
single axon
multipolar neurons are found as which type of neurons
interneurons and motor neurons
in which type of nervous system are interneurons normally found
the CNS
interneurons are aka
relay neurons
glial cells
non-neuronal cells that provide support and protection to neurons in the nervous system
the 6 types of cells that the glial cells are comprised of
Astrocytes
Microglia
Oligodendrocytes
Ependymal
Schwann cells
Satellite cells
glial cells are divided into two parts, name them.
neuroglial cells
non-neuroglial cells
which of the 6 cell types of fall under the neuroglial cells
astrocytes
oligodendrocytes
microglial
ependymal
which of the 6 cell types of fall under the non-neuroglial cells
Schwann cells
satellite cells
in which type of nervous system are neuroglial cells found
in the CNS
in which type of nervous system are non-neuroglial cells found
PNS
functions of the ependymal cells
creates barriers between cell compartments
they are a source of neural stem cells
functions of astrocytes
they are a source of neural stem cells
they take up K+, water and neurotransmitters
they secrete neurotrophic factors
they help form the blood-brain barrier
they provide substrates for ATP production
functions of microglia cells
they act as scavengers
function of oligodendrocytes
they form myelin sheaths
functions of Schwann cells
they form myelin sheaths around the axons of neurons
they secrete neurotrophic factors
they assist neuronal repair
functions of satellite cells
they support cell bodies
advantages of myelinated cells
they conduct nervous impulses more rapidly, and enable saltatory conduction
neurotrophic factors
a family of proteins that play a crucial role in the growth, survival, and maintenance of neurons
our of all the neuron classes, which one is unmyelinated
pseudounipolar neurons
white matter is comprised of which parts of neurons?
while grey matter is comprised of?
myelin
cell bodies and dendrites
the forms of nervous signals
electrical and chemical
chemical signalling in the nervous system is one-way, true or false?
true
electrical signalling in the nervous system is one-way, true or false
false
can be either one way(unidirectional) or two way(bidirectional)
gap junction
a specialized intercellular communication structure formed by the interaction of connexins, transmembrane proteins that create channels connecting the cytoplasm of adjacent cells
connexon
a channel formed by six connexins
how many connexons combine to form a gap junction channel
two
which particles can gap functions facilitate the exchange of?
major cellular ions and many small organic molecules
cells connected by gap junctions are said to be………………………. coupled
electrically
what are some cells that use the gap junctions
GI epithelium
Skin epithelium
Smooth Muscle
Cardiac Muscle
what are some advantages of electrical transmission in the nervous system
Bidirectional Communication between cells
Electrical signals can travel at high speeds through the axons of neurons
enables continuous signalling
simultaneous action potential generations
state the approximate sizes of;
gap junctions
synaptic cleft
3.5nm wide
20-50nm wide
major neurotransmitters within the CNS
GABA
Glutamate
Ach
Serotonin
Noradrenaline
Adrenaline
major neurotransmitters within the CNS AND PNS
Acetylcholine
Noradrenaline
the calcium gated channels are said to be voltage gated, true or false
true
name three ways by which neurotransmitters are taken away from the synapse
Diffusion
reuptake
Enzymatic degradation
enzymatic degradation
the process by which enzymes break down complex molecules into simpler ones.
ionotropic receptors aka
ligand gated ion channels
metabotropic receptors aka
G-protein coupled receptors
which is more selective to ions, ionotropic or voltage gated channels
voltage gated channels
GPCRs can also be presynaptic, true or false
true
