G10 Nervous System & Homeostasis(Slides) Flashcards
body’s master controlling system.
It performs our thoughts and actions.
Nervous System
Basic components of the Nervous System
brain
spinal cord
neuron
Two major divisions of the Nervous System
central nervous system (CNS)
periphereal nervous system (PNS)
composed of the brain and spinal cord which act as integrating command centers
central nervous system (CNS)
consists of the neurons that link the body organs to the CNS.
peripheral nervous system (PNS)
are the basic units of the nervous system
are highly specialized cells that transmit nerve impulses or electrical messages from one body part to another
Neurons (nerve cells or nerves)
two common features of all types of neurons
cell body
neural processes or extensions
parts of a neuron
cell body (soma)
neural processes
synapse
myelin sheath
center of a neuron as it contains the nucleus
cell body (soma)
serve as passageways of signals
“arm-like” neural processes
transmit electrical signals toward the cell body
neural process
Dendrites
generate impulses away from the cell body
neural process
Axons
The axons branch out into hundreds of axon terminals, the small vessels that contain the neurotransmitters or chemical messengers of signals.
small vessels that contain the neurotransmitters or chemical messengers of signals
axon terminals
extracellular gap that links the neurons together
Synapse
a fatty material that insulates the neural processes
Myelin sheath
Classifications of Neurons
functional classification
structural classification
is based on the direction through which the nerve impulses travel relative to the CNS
(classification)
Functional classification
is based on the direction through which the nerve impulses travel relative to the CNS
(classification)
Functional classification
functional classification of neurons
sensory neurons/afferent neurons
motor neurons/efferent neurons
interneurons/assosications neurons
carry impulses from sensory receptors to the CNS
Sensory neurons
referred to as afferent neurons, which literally means “to go toward.”
Sensory neurons
carry impulses from the CNS to the muscles and glands of our body
Motor neurons
referred to as efferent neurons which means “away from”
Motor neurons
link the sensory and motor neurons to keep the flow of impulses between neurons
Interneurons
are also called as association neurons
Interneurons
based on the number of neural processes that extend from the cell body
(classification)
Structural classification
structural classification of neurons
multipolar neuron
bipolar neuron
unipolar neuron
has several dendrites and an axon
multipolar neuron
All motor neurons and interneurons have this kind of neural structure.
multipolar neuron
All motor neurons are _
multipolar
are those that have one axon and one dendrite
Bipolar neurons
are those that have one axon and one dendrite.
They are only found in sensory organs, like the ears and eyes, where they act as sensory receptors.
Bipolar neurons
consist of a single neural process that extends from the cell body in the form of an axon
Unipolar neurons
conducts nerve impulses both toward and away from the cell body
Unipolar neurons
act as sensory neurons
Structural classification
unipolar neurons
supporting cells that lump together to support and protect the nerve cells
cannot transmit impulses
Neuroglia (“nerve glue”)
Neuroglia of the CNS
Astrocytes
Microglia
Ependymal cells
Oligodendrocytes
star-shaped cells with numerous projections that insulate most of the neural tissues
Astrocytes
most abundant type of neuroglial cells in the CNS
Astrocytes
spider-like cells that act as phagocytes to eliminate dead brain cells and bacteria found wandering in the brain
Microglia
serve as the protectors of the CNS
Microglia
form a series of cells that line the cavities of the brain and the spinal cord
Ependymal cells
Specialized ependymal cells produce the
cerebrospinal fluid (CSF)
are the supporting cells that produce the insulative myelin sheaths of the neural processes in the central nervous system
Oligodendrocytes
Neuroglia of the PNS
Schwann cells
Satellite cells
are specialized supporting cells that produce the myelin of neurons in the PNS
Schwann cells
Have exposed membranes and cytoplasms; their CNS counterparts do not have
Schwann cells
are flattened supporting cells wrapped around the cell bodies of sensory neurons in PNS
Satellite cells
Their main function is to act as protective cushioning cells
Satellite cells
General Functions of the Nervous System
sensory perception
integration
response production
Sensory receptors incorporated in our organs receive different internal and external stimuli all the time called
sensory input
Electrical signals sent by the sensory receptors are assessed in the brain through _ in which the involved organs will be tapped to create a response
integration
Once the electrical signals have been assessed, the nervous system will activate the appropriate muscles or glands to create a response called the
motor output
The nervous system is able to perform its functions as the control and coordinating center of all our organ systems.
However, it still needs the help of the other systems for the body to function optimally.
