Nervous System
3 main functions of a simple nervous system
Sensation, Integration, and Response
The two primary cell types of the nervous system are _______ and _________.
neurons; glial cells
What does a ligand-gated channel require in order to open?
b. binding of a neurotransmitter
Which ion enters a neuron causing depolarization of the cell membrane?
sodium
In a simple synapse, neurotransmitter chemicals are released by
a. cell bodies
b. axon hillock
c. dendritic membrane
d. presynaptic membrane.
d. presynaptic membrane
2 main functions of PNS and their respective functions
Afferent Division-has sensory information flow from receptors outside the CNS towards an integrating center (Sensory division).
Efferent Division-has information flow from the CNS to effectors in the periphery (Motor division).
Which part of the neuron transmits an electrical signal to a target cell?
Axon
Which ion is pumped into a cell by the sodium-potassium pump?
potassium
A channel opens on a postsynaptic membrane that causes a negative ion to enter the cell. What type of graded potential is this?
Hyperpolarizing
Which type of channel opens at the presynaptic terminal upon the arrival of an action potential?
a. K+ channel
b. Ca2+ channel
c. Na+ channel
d. Cl- channel
b. Ca2+ channel
2 subdivision of an autonomic nervous system and their function.
Parasympathetic nervous system- rest and digestion (conserves body resources)
Sympathetic nervous system- flight and fight response (uses body resources)
Glial cells of PNS and CNS
PNS- Schwann cells
CNS- Astrocytes, Ependymal cells, Oligodendrocytes, and Microglia.
Which ion channel is primarily responsible for the action potential?
a. The voltage-gated sodium channel.
b. The voltage-gated potassium channel.
c. The ligand-gated sodium channel.
d. The ligand-gated potassium channel.
a. The voltage-gated sodium channel.
No Threshold
Graded Potentail
Voltage-gated sodium channels open upon reaching what state?
a. resting membrane potential
b. repolarization
c. threshold
d. overshoot
c. threshold
2 subdivisions of Efferent division and what their function is
Somatic nervous system- innervates skeletal muscles.
Autonomic nervous system- control functions of smooth muscles, cardiac muscles, and glands.
The outer layer, formed by the Schwann cells, that wraps around a PNS neuron is called?
Myelin Sheath
How do active transporters and ion channels contribute to resting membrane potential?
Active transporters create and maintain ion concentration gradients and ion channels allow ions to diffuse down their concentration gradients which aid in the selective permeability of the membrane. This creates a difference in ion concentration which gives rise to the resting membrane potential.
A typical neuron has a resting membrane potential of approximately -70 mV. How would the potential change if the conductance of K+ suddenly increased?
a. The potential would rise (get more positive)
b. The potential would stay the same
c. The potential would drop (get more negative)
c. The potential would drop (get more negative)
During the falling phase of the action potential, most voltage-gated K+ channels are
a. inactivated
b. open
c. closed
d. dephosphorylated
b. open
You are taking BIOL 1082 final exam, and your heart starts racing, your hands are getting sweaty and you lose all appetite. Which division of your autonomic nervous system likely just kicked in?
Sympathetic
Which of the following is not one of the functions of the Schwann or oligodendrocyte or glial cells?
A. Supporting neurons during embryonic development
B. Supplying nutrients
C. Conducting nerve impulses
D. Consuming foreign particles
C. Conducting nerve impulses
The Na/K pump transports ______ out and ______ into the cell. What kind of pump is this? What does it use as an energy source?
3 Na are transported out for every 2 K that are moved in. It is an active transporter (ATPase Pump) that directly uses ATP.
Which of the following is correct in regards to action potentials?
a. They are all or none signals that are generated once and travel passively along the axon.
b. They are graded potentials that are generated once and then travel passively along the axon.
c. They are continuously renewed as the signal travels along the axon.
c. They are continuously renewed as the signal travels along the axon.
In multiple sclerosis, the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results. How does this disease manifest at the level of the action potential?
a. Action potentials move in the opposite direction on the axon.
b. Action potential move more slowly along the axon.
c. Action potentials are entirely negated.
d. All of the above occurs in multiple sclerosis.
b. Action potential move more slowly along the axon.