Anatomy and Phys Endocrine and NS Quiz Flashcards
Describe the homostatic control mechanism of the NS
- stimulus
- receptor detects vis sensory skin cells
- input of info (afferent pathway) to the control center
- info sent to efferent pathway and to an effector
- response of body is to return to homeostasis
describe the difference between the afferent and efferent pathway
SAME DAVE
afferent: signals delivered to CNS
efferent: signals delivered away from CNS
what are the 2 sub-categories of the peripheral NS
- sensory (afferent): sensory organs
- motor (efferent): combines voluntary and involuntary actions
what are the 2 sub-categories of the motor (efferent) pathway
- somatic (voluntary)
- autonomic (involuntary): parasympathetic (relax) and sympathetic (excite)
there are 2 main cells of the NS, what are they?
Neurons and neuroglia
neurons send and receive signals while neuroglia support this process.
name the Three General Types of Neurons
- Sensory Neurons: Transmit sensory information from receptors to the CNS.
- Interneurons: Process and relay signals within the spinal cord of the CNS.
- Motor Neurons: Carry signals from the CNS to effectors like muscles or glands.
what are the 3 properties of all neurons?
- excitable (receive signals)
- conductive (send signals)
- secretory (release NT)
define a nerve
a bundle of nerve fibers (axons) bound together by tissues
the bundle protects the axons when traveling long distances
describe how a signal travels down a neuron
Dendritic input and integration of incoming signals.
Action potential initiation if threshold is reached.
Rapid depolarization as sodium ions enter the neuron.
Propagation of the action potential along the axon.
Repolarization as potassium ions exit the neuron.
Refractory period to prevent immediate firing.
Propagation to axon terminals.
NT release into the synaptic cleft.
NTs bind to receptors of postsynaptic neurons.
Postsynaptic response: excitatory or inhibitory.
Integration of postsynaptic signals.
describe SAME DAVE
sensory - afferent
motor - efferent
dorsal- afferent
ventral- efferent
what is a ganglion
collection of neuronal cell bodies of the PNS. found in the dorsal root
(called nuclei in the CNS)
what are the 3 layers of the CONNECTIVE TISSUE SHEATHS OF PERIPHERAL NERVES
On the outside of each peripheral nerve, there is collagenous tissue: epineurium. Surrounding every fascicle within the nerve is the perineurium. Individual nerve fibers within the fascicles are embedded in endoneurium, which fills the space bound by the perineurium.
which voltage gates are slow and which are fast?
slow: Na+ inactivation and K+ activation
fast: Na+ activation
what is the toxin that prevents action potentials?
tetrodotoxin; found in fugu sushi. blocks NS cell signaling and can lead to flaccid paralysis
describe the signaling path through the peripheral nervous system.
Sensory Receptors detect stimuli.
Sensory Neurons Transmit signals to the CNS.
CNS interneuron processes information
Motor Neurons send signals to effectors
muscles/glands respond
describe a membrane potential, how it is maintained, and why it is important.
Membrane Potential: Voltage difference across a cell’s membrane.
Maintenance: Achieved through selective ion permeability, ion pumps, and leak channels.
Importance:
Essential for nerve and muscle function
Drives cell signaling (action potentials)
Maintains ion balance
describe the CNS vs the PNS
CNS: brain and spinal cord
PNS: all neurons sending signals to and from the body
explain how voltage-gated channels operate during an action potential.
Sodium Channels (Na+):
- Open: During depolarization (rising phase).
- Close: Shortly after opening (inactivation) and remain closed during repolarization.
Potassium Channels (K+):
- Open: During repolarization (falling phase).
- Close: Once the membrane potential returns to its resting state.
explain the concept of a threshold stimulus and the three phases of an action potential
- Depolarization: Membrane becomes positive. Na+ flows in
- Repolarization: Returns to resting state. Na+ gate closes, K+ finally opens and lets out K+
- Hyperpolarization: Briefly more negative than resting state.
*Return to resting potential (-70) until threshold (-55) is reached again