Lecture 2 - Cells of the Nervous System Flashcards
Central Nervous System (CNS)
- comprised of the brain and spinal cord.
- encased within the skull and spinal column.
Peripheral Nervous System (PNS)
comprised of nerve tissue located outside of the brain and spinal cord.
Can nerves regrow, if damaged in the CNS or PNS?
nerves can regrow if damaged in the PNS only
What is part of the basic structure of a neuron?
- soma
- dendrite
- axon hillock
- axon
- terminal button
- synapse
Soma
The cell body of a neuron, which contains the nucleus
Dendrite
A branched treelike structure attached to the soma of a neuron; receives information from the terminal button of other neurons
Axon hillock
Site of summation for incoming information
Axon
The long, thin cylindrical structure that conveys information from the soma of a neuron to its terminal button
Terminal button
The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron
Synapse
A junction between the terminal button of an axon and the membrane of another neuron
What are the 4 basic components of a neuron?
input, integration, conduction, output
Describe the information flow of neurons
- Information from other neurons is collected at dendrites
- processed in the cell body,
- passed on to the axon,
- then to the end feet, where it is passed on to a target neuron
Describe Terminal buttons
end point of axons – transform electrical signal from the axon into a chemical signal sent across the synaptic cleft.
Neurotransmitter
A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron.
What are the 3 classifications of neurons in terms of SHAPE?
- Bipolar neurons
- Multipolar neurons
- Unipolar neurons
Bipolar neurons SHAPE
A neuron with one axon and one dendrite attached to its soma.
SENSORY
Multipolar neurons SHAPE
A neuron with one axon and many dendrites. Most common in CNS.
Unipolar neurons SHAPE
A neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system.
SOMATOSENSORY (TOUCH, PAIN)
What are the 2 classifications of neurons in terms of SIZE?
- large (e.g., pyramidal)
- small (e.g., granular)
Sensory neuron FUNCTION
transmits sensory information to the central nervous system.
ex: somatosensory (pressing on skin - sends signal to brain)
Motor neuron FUNCTION
controls the contraction of a muscle or the secretion of a gland.
ex: MOVE arm if you don’t like being touched
Interneuron FUNCTION
located entirely within the central nervous system.
ex: connect everything (in order for muscle to contract for ex, part of the circuit)
- in b/t helpers
The Mighty Neuron!
- 1 neuron receives info from the end feet of another neurons
- if that info summates at the axon hillock and theirs enough to drive an AP (electrical signal down the axon)
- we then can get connections with other neurons, forming synaptic connections where n.t. is released & we influence the neighbouring neurons all forming part of a network
Internal mileu
chemical makeup inside cell body
contains:
- membrane
- cytoplasm
- nucleus
- mitochondria
- adenosine triphosphate (ATP)
- Endoplasmic reticulum (rough & smooth)
- Golgi apparatus
- Lysosome
Membrane
A structure consisting primarily of lipid (fat-like) molecules that makes up the outer boundary of a cell.
- (like skin)
Cytoplasm
The viscous, semi-liquid substance inside the cell. GOOP!