Question | Answer |
What are the functions of the nervous system? | 1. receives inputs from outside and inside the body
2. Processes and interprets sensory input
3. Sends response to effector organs (motor output) |
What is the central nervous system composed of? | Brain and Spinal Cord |
What is the Peripheral Nervous System composed of? | 1. Cranial nerves and ganglia (12)
2. spinal nerves and ganglia (31) |
What is the brain and spinal cord covered by? | Meninges |
What are the 3 layers of Meninges? | 1. Dura
2. Arachnoid
3. Pia maters |
Where is the CSF (Cerebrospinal fluid)located? | In brain and spinal cord in the subarachnoid space |
What do neurons do and where are they found? | Transmit electrical signals and are found in grey matter of CNS and ganglia |
What are neuroglial cells? | 1. Support cells
2. nonexcitable
3. surround and wrap neurons |
What are the 4 neuroglial cells in the CNS? | 1. Astrocytes
2. Microglia
3. Ependymal cells
4. Oligodendrocytes |
What is the function of Astrocytes? | 1. Most abundant glial cell
2. Take up and release ions to control the environment around neurons
3. Recapture and recycle neurotransmitters |
What is the function of Microglia? | 1. Smallest and least abundent
2. Phagocytes: macrophages of the CNS |
What is the function of Ependymal Cells? | Line central cavity of the spinal cord and brain |
What is the function of Oligodendrocytes? | Produce myelin sheath in CNS |
What are the 2 types of Neuroglial cells in PNS? | 1. Satellite Cells
2. Schwann cells |
What is the function of Satellite cells? | Surround neuron cell body
Blood brain barrier |
What is the function of Schwann cells? | Form myelin sheath around axons of PNS |
What does Neurotransmitters do and where are they released from? | 1. Excite/ inhibit neurons
2. axon terminals |
What is a Synapes? | Site at which neurons communicate
(pre, post) |
Where are the Na+ channels located in axons? | nodes of ranvier-signal jumps from node to node |
What is an action potential? | short-lasting excitation of cell, membrane potential of cell rises rapidly then falls |
What is the resting membrane potential? | -80mV (net charge outside is positive and inside negative) |
How does Neuron maintain polarity after action potential? | Pump out Na+ and pump in K+ |
What are the connective tissues of the nerve from inside out? | 1. Endoneurium- surrounds axon
2. Nerve Fascicles- group of axon in bundle
3. Perineurium- surrounds nerve fascicle
4. Epineurium- covers whole nerve in tough fibrous sheath |
What is the Conus medullaris? | Terminal end of the spinal cord, near (L1)and(L2) |
What is the Cauda equina? | Dangling nerve roots of spinal cord after Conus medullaris |
What is the Filum Terminale? | Terminal nerve root tail |
What are the 5 essential components of the reflex arc? | 1. Receptor
2. Sensory neuron
3. Integration center
4. Motor neuron
5. Effector |
Describe receptor component of reflex arc | Site where stimulus acts |
Describe sensory neuron component of reflex arc | transmits afferent impulses to CNS |
Describe integration center component of reflex arc | consists of one or more synapses in the CNS |
Describe motor neuron component of reflex arc | Conducts efferent impulses from integration center to an effector |
Describe effector component of reflex arc | Muscle or gland cell that responds to efferent impulses
Contracts or secretes |
What does the Reflex arc bypass? | Brain |
What is monosynaptic reflex and a good example? | Reflex upon 1 synapse (fastest)
Ex. knee-jerk reflex |
What is polysynaptic reflex and a good example? | Reflex upon multiple synapse (more common)
Ex. Withdrawal reflexes- burn finger, withdraw finger and arm |