Ch 11: Control: The Nervous and Endocrine Systems Flashcards
The nervous system consists of billions of _____ which do what?
Neurons, carry impulses/ electrical signals between body parts
Label the neuron
|\____|\_____||||\
——————————–|\________________
———–O—————– __________________0
_____||\___|\_____
|\____|\_____||||\
- —cell body—————|\_________________
- ———-O-
How does an impulse travel through a neuron?
It is received at the dendrites, then transmitted through the cell body and down the axon
What does it mean when we say a neuron is polarized?
It is different on one side of its membrane than the other (the inside is negatively charged when compared to the outside of the neutron)
What is the resting membrane potential of most cells?
-70 mV
The ________ is a membrane protein that pumps 3 sodium ions out of the cell and 2 potassium ions into the cell
sodium-potassium pump (Na+/K+ ATPase)
Can sodium ions cross back into the cell after being pumped out?
No
Do dendrites receive or transmit an electrical impulse?
Receive
The direction in which an impulse travels through a neuron is _____ to _____ to _____
dendrites, cell body, axon
Is potassium concentration is ______ inside the cell than outside
Higher
The resting membrane potential of the cell is _____
-70 mV
Sodium concentration is _____ inside the cell than outside
lower
The axon of a neuron carries the nerve impulse _____ the cell body
away from
What is a leak channel?
Channels that will always allow potassium to leak out of the cell according to its gradient (there is more potassium inside the cell than outside, so it will leak out)
What is a voltage-gated channel?
Channels that open when the cell membrane reaches a particular voltage (-50 mV) (also known as threshold potential)
What does it mean when a neuron is polarized?
The state of the membrane at rest, negative on the inside and positive on the outside
What is depolarization?
The membrane potential moves in the positive direction
What is repolarization?
The membrane potential returns to its resting value
What does depolarization result from?
An influx of sodium ions
Rapid, “jumping” conduction is called:
saltatory conduction
A return to the resting, polarized state is called:
Repolarization
The small portion of a neuron’s membrane that is undergoing an action potential is relatively ____ on the inside and _____ on the outside.
positive, negative
Repolarization results from an ____ of ____ ions
efflux, potassium
The time during which a portion of the membrane is unable to fire an action potential (because it just fired one) is called the:
Refractory period
In a myelinated axon, action potentials occur only at the:
nodes of Ranvier
Ion channels that open at a particular membrane potential are said to be:
voltage-gated
A neuron whose resting potential is moving away from threshold is said to be ______
inhibited
The small space between the axon terminus of one neuron and the dendrites of the next neuron is called the _________
synaptic cleft
A synapse can be found between a neuron and _____
neuron or organ
The most common neurotransmitter in the body is _________
acetylcholine
A neurotransmitter is released from ______ and binds to _______
vesicles, receptors
Receptors that open sodium channels would cause the neuron to _______
depolarize
A neuron will fire an action potential only if its membrane potential reaches _____
threshold
What do chemical synapses use to pass the impulse from one neuron to the next?
neurotransmitters
What is a synapse?
The point where the impulse gets transferred
The CNS consists of the _____ and the _________
brain, spinal chord
