Lecture 1 Flashcards
What is the general function of our nervous system?
control, regulate, and communicate
What are the separate components of both the Central and Peripheral Nervous Systems?
Central - brain and spinal cord
Peripheral - somatic and autonomic nervous system
What are the main components of the neuron? For each component, what is its role in neuronal activity?
- dendrite - receive info
- soma - integration center
- axon hillock - transmit AP to axon
- axon - carry output signal
- terminal branches - filled with neurotransmitters to transmit signal when stimulated
What are the 3 types of neurons that can be found in the nervous system? In general, where can each be found within our CNS?
- multipolar - soma w/ singular axon, multiple dendrites, multiple terminal branches (CNS)
- bipolar - single dendrite and single axon arising from cell body (special sensory organs like eyes)
- (pseudo) unipolar - axon and dendrite arise from a single process coming out of the soma (PNS)
What is the main role of sensory/afferent neurons, and what types of afferent neurons are found in the nervous system?
- bring single up from PNS to CNS
- special sensory (vision, auditory, equilibrium, gustatory or taste)
- viscerosensory (unconscious transmission from internal organs)
- somatosensory (conscious transmission from skin, muscle, and joints)
What is the main role of motor/efferent neurons, and what types of afferent neurons are found in the nervous system?
- send signal from CNS to PNS
- somatomotor - (voluntary contractions)
- autonomic motor (involuntary contractions)
What is the function of interneurons/associative neurons?
local integration centers that connect sensory and motor neurons
Define a reflex and reflex arc. What types of reflexes can be found in the human body?
- reflex - unidirectional rapid, predictable, and involuntary response to a stimulus
- reflex arc - neural pathway that controls a reflex (sensory receptor - sensory neuron - interneuron - motor neuron - effector)
- types of reflexes - somatic (skeletal muscle) and autonomic (smooth muscle)
Explain the steps of the myotatic reflex, starting from the hit of the hammer to the leg kicking outwards
1) hammer hit which stretches sensory receptors in leg extensor muscle
2A) sensory neuron synapses with and excites motor neuron in spinal cord
2B) sensory neuron excites spinal interneuron
2C) interneuron synapse inhibits motor neuron to flexor muscles
3A) motor neuron conducts AP to synapses on extensor muscle, causing contraction
3B) flexor muscle relaxes b/c activity to motor neuron has been inhibited
4) leg extends
Explain the steps of the Flexor Withdrawal Reflex. When does this reflex come into play in function?
1) painful stimulus
2) sensory neuron activates multiple interneurons
3) Ipsilateral motor neurons to flexor excited
4) Ipsilateral flexor contracts
5) contralateral motor neurons to extensor excited
6) contralateral extensor contracts
Describe the function of astrocytes. What are their PNS equivalent?
- support cells
- repair damage, regulate communication between neurons, provide nutritional support, provide insulation to isolate electrical activity of adjacent neurons, regulate intercellular calcium which affect neurotransmitters
- PNS equivalent are satellite cells
Describe the function of ependymal cells. Where are they specifically found?
- form choroid plexus, facilitate CSF exchange, and produce CSF
- found in ventricle and central canal walls
Describe the function of microglia.
- primary defense system
- remove foreign bodies
- protect against infection
Describe the function of oligodendrocytes and Schwann cells. Where are they each located and what are the major differences between the two?
- create and maintain myelin in CNS (oligodendrocytes) and PNS (Schwann)
- oligodendrocytes can myelinate multiple axons in CNS while multiple Schwann cells are needed to myelinate one axon in PNS
What is the role of myelin? Describe its basic anatomical features.
- gives white matter its white appearance
- insulates axon for quick AP transmission
- mixture of proteins and phospholipids that wrap around axon