Lecture 16: Cells and organization of the nervous system Flashcards
What does integrating and coordinating mean to the nervous system
Senses environment
Produces an appropriate response
What are the two parts of the nervous system
Central nervous system and Peripheral Nervous System (Including ENS)
What is the ENS
The Enteric Nervous System (ENS) is a complex network of neurons that controls the functions of the gastrointestinal tract
Can work independently of the CNS
What does the Central nervous system consist of
Brain and spinal chord
What 2 cell classes make up the CNS
Neurons and Glia
What are Glia
Non-neuronal cells in the nervous system that play a crucial role in supporting and maintaining the functions of neurons
What does the PNS consist of
Peripheral nerves and Ganglia
What 2 cell classes compose the PNS
Neurons and Glia
What are Neurons
Nerve cells. Cells specialized for transmission of information
How many morphological types of neurons are there
- Unipolar, Bipolar, Axonic (axonless), multipolar
How many types of glia are there
Five basic types
4 in CNS, 1 in PNS
Each type has a specific function
What are the functions of the dendrites
Receive input
Send info to cell body
What are the 2 features of the cell body of the neuron
It contains the nucleus and organelles
Sums input
What is the function of the axon (and an important feature)
Carries electrical impulses
The axon may or may not be myelinated
What is the axon terminal and what does it do
End of the axon
Neurotransmitter release
In the CNS what is a bundle of axons called
A tract
In the CNS what are groups of cell bodies?
Nucleus
What is grey matter (CNS
Group of cell bodies in cerebral cortex or spinal cord
What is white matter (CNS)
bundle of axons in cerebral cortex or spinal cord
long fiber tracts
What is the cerebral cortex
The cerebral cortex is the outer layer of your brain’s surface, located on top of the cerebrum
What does the term soma refer to
Cell bodies of neurons
What parts of the neuron are in the input zone
Dendrites and cell body
What happens in the input zone of the neuron
Receives chemical signals from other neurons
What parts of the neuron are in the summation zone
axon hillock
What is the function of the axon hillock
Summation of inputs and deciding whether to send a signal down the axon
What is the role of the conduction zone of the neuron and what structure does it consist of?
The axon is in the conduction zone
Its role is to carry electric signals between brain areas to and from spinal cord or from peripheral sensory receptors and to effector cells
What happens at the output zone of neurons and what does it consist of
Consists of Axon terminals
Contact with input zone of other neurons or effectors
Releases neurotransmitter (Chemical signal)
Why do cells of the nervous system look different
Because they are specialized for specific tasks
What does multipolar mean in terms of morphological types of neurons
Multiple processes emanate from the cell body
What does bipolar mean in terms of morphological types of neurons
Two (2) processes emanate from the cell body
What does unipolar mean in terms of morphological types of neurons
One process emanates from the cell body
Then branches into dendrite and axon
What does axonic mean in terms of morphological types of neurons
Axonless, No distinct axon. All processes look alike
What are the 4 types of cells in the CNS
Astrocytes, Microglia, Ependymal cells, Oligodentrocytes
What are astrocytes in the CNS and what is their function
Most common type of Glia
They supply nutrients to neurons, cover blood capillaries, repair damage in the CNS
What is are microglia in the CNS and what is their function
The immune cells of the CNS
They engulf microorganisms and debris
What is are Ependymal cells in the CNS and what is their function
They line fluid-filled spaces of the brain and spinal cord
They have cilla (hair like) processes to circulate cerebrospinal fluid
What is are oligodendrocytes in the CNS and what is their function
They support CNS nerve fibers and ensheath them with myelin
What are Shwann cells
They support PERIPHERAL nerve fibers and ensheath them with myelin
Where does the myelin sheath come from in CNS and PNS
CNS - Oligodendrocytes
PNS- Schwann cells
What is the myelin sheath and what is its function
Multiple Schwann cells in line
Lipid (fat) wrapped around axon. It increases conduction velocity
What are the nodes of Ranvier and what is their function
Gaps between myelin that increase conduction velocity
How do Schwann cells contrast with oligodendrocytes
Oligodendrocytes associate with more than one Neruron
What is a synapse in neurons
This is the junction where communication between neurons occurs
What are synaptic vesicles and where are they found
little packets of neurotransmitter, found in pre-synaptic neuron (Before the synapse)
What is the neuron after the synapse called and what does it contain
Post-synaptic neuron, contains receptors for neurotransmitter
What do we call information that goes INTO the brain (ascending)
Afferent
What do we call infromation coming out of the brain (descending)
Efferent
Is sensory information afferent or efferent.
Afferent.
Is Motor information afferent or efferent.
Efferent
The myelin sheath in the CNS is made by:
Oligodendrocytes
The part of neurotransmission that is carried out through a chemical signal is called:
Synapse
The part of a neuron where summation of inputs takes place is called:
Axon Hillock
