Exam 2: Neuron Stuctures/Functions Flashcards
Which ends of a neuron receive information?
Dendrites
What is another name for the cell body?
Soma
Is there myelination on the dendrites?
Not much if any
Which end of a neuron sends information?
Axon
T/F Axons are not myelinated
False
What is the node of Ranvier?
The nodes between the myelin sheath where sodium can jump from one to another
Is the end of the axon presynaptic or postsynaptic?
Presynaptic
Where is the axon hillock?
The beginning part of the axon
Which neurotransmitter is used at the axon hillock?
GABA
What does GABA do to the cell?
Increases chloride permeability into the area of the neuron, suppressing activity or putting on the “brakes”
What happens if we ignore GABA?
We will have over-the-top crazy levels of activity including seizures
T/F Postsynaptic neural connections can be excitatory and inhibitory
True
Where are excitatory neural connections found?
In areas where the dendrites are
Are dendrites more positive or negative than the average membrane potential?
Positive
Are inhibitory connections more positive or negative than the average membrane potential?
Negative
What are the supporting cells of the nervous system?
Astrocytes
Ependymal Cells
Oligodendrocytes
Schwann Cells
Microglia
Which supporting cells are the smallest?
Microglia
What is the most abundant type of glial cell?
Astrocyte
What do astrocytes do?
They wrap around the true part of the blood brain barrier and provide a supporting structure. Astrocytes are helpful with maintaining electrolyte balance and repairing neurons after any neuronal injury.
Which nervous system do astrocytes support?
Central nervous system
What are ependymal cells?
Ependymal cells contain cilia which helps produce CSF and move the CSF to ensure it circulates around the brain and spinal cord in waves
What are microglia cells?
Microglia cells are cells that act as macrophages. They keep the area around the CNS clean and free of debris
What are the 4 types of neurons? (Hint: Schmidt said to only worry about 3 but there’s 4 in the PPT)
- Multipolar
- Pseudounipolar
- Bipolar
- True Unipolar (NOT WORTH EXPLAINING) - not found in humans
What are multipolar neurons?
Multipolar neurons have dendrites and connections with other parts of the CNS and play a role in decision making. They take lots of information and make a decision on whether to fire an action potential or not
Ex: Motor neurons or pain neurons that tell us to pull away from something painful
Think: decision maker
What are bipolar neurons?
Bipolar neurons are neurons that contain 2 projections and are designed to sense and pass along information as an action potential to another area of the brain
Think: Special sensory
Where do we find bipolar neurons?
Optic nerve; photoreceptors in the retina send messages through the optic nerve and create specialize senses
What are pseudounipolar neurons?
Neurons that make up the majority of sensory cells; the cell body (which mostly builds proteins and maintains things) does not make decisions and instead, it relays information from the dendrite to the axon and passes the information to the rest of the nervous system.
What are somatic sensory receptors?
Specialized structures designed to be good at sensing certain things
Somatic= can consciously sense, we are aware of it
Ex: Pain sensors, pressure sensors, etc.
What do free nerve endings do?
Sense Pain
What is another term for free nerve ending?
Nociceptor
Name 3 pressure sensors
Pacinian corpuscle, Meissner’s corpuscle, Golgi Tendon
What is a muscle spindle?
Stretch sensor that is woven into skeletal muscle that can confirm muscle contraction
Adaptation
A sensor’s ability to reset its baseline with prolonged exposure to a stimulus
Give an example of a a sensor that adapts to changing conditions
Baroreceptors readjusting to high blood pressure
What receptors undergo reverse adaptation? What does this mean?
Pain Receptors
The longer the pain is sensed, the worse the pain will feel