biology unit 2 exam Flashcards
The place where two neurons meet, or a neuron meets another cell
Synapse
What is the role of the interneuron in the reflex are described in the narrative?
To connect the sensory and motor neurons
Which of the following are true about reflexes?
Respond to stimuli more quickly than voluntary
Reflexes are involuntary
Reflex processing does not require the brain
Single EPSPs are enough to trigger the rising phase of an action potential
False
The ______, the input zone of the neuron, may be the site of the generation of an action potential
Dendrites
Which of the following best describes the trigger zone after an EPSP has been received?
The trigger zone depolarized
During the resting potential, the outside of a nerve cell is _____ charged compared to inside
Positively
During the action potential, the outside of the nerve cell is _______ charged with respect to the inside
Negatively
After repolarization, the outside of the nerve cell is _______ charged with respect to the inside
Positively
Release by presynaptic neurons depolarizes a postsynaptic neurons axon hillock, producing an EPSP that depolarizes the neurons axon hillock
Neurotransmitter
Called Schwann cells form the insulating myelin sheath around axons
Glial cells
An example of a synapse could be the site where….
Neurotransmitters released by an axon travel across a gap and are picked up by receptors on a muscle cell
The resting membrane potential in neurons requires ….
The diffusion of K+ out of the cell and a charge separation between the inside and outside of the axon set up by this movement of K+
The major role of the Na+ and K+ pump is to
Maintain the resting membrane potential at a constant negative value
In the propagation of an action potential
The refractory period begins as the K + channel opens, allowing K+ ions to flow outward along their concentration gradient
Which of the following does not contribute to propagation of action potentials
Each segment of the axon prevents the adjacent segments from firing
It transmits the action potential at the nodes of ranvier and thus speeds up the action potentials on myelinated axons
Saltatory conduction
transmission of a neural signal to its target cell requires…
An action potential to open the Ca 2+ gates so that Ca2+ ions, in higher concentration outside the axon, can flow back into the cytoplasm of the neuron
How does activating metabotropic receptors differ from activating ionotropic receptors?
Activating metabotropic receptors prices longer lasting effects on postsynaptic neurons
Which of the following are part of the central nervous system?
Central nervous system and spinal cord
Which of the following best describes the role of the autonomic nerves in the body?
Control of involuntary functions including the cardiac muscles and glands
The “fight or flight” response occurs when which group of neurons is activated?
The sympathetic neurons
Which neural circuit motif regulates the overall level of excitation?
Feedforward excitation