Chapter 34.1-34.3- Nervous systems

Question 1

Sensory neurons

Answer 1

receive and transmit
information about an animal’s
environment (ex. temperature and
internal physiological state)

Question 2

Interneurons

Answer 2

Process information from
sensory neurons and transmit it to
different body regions to produce a
response

Question 3

Motor neurons

Answer 3

stimulate a muscle
response or constrict blood vessels or
cause wavelike contractions of the gut to aid digestion

Question 4

Facts about animal neurons:

Answer 4

• dendrites and axon terminal are highly branched
• Neurons sends signals through action potentials
• action potentials provide long distance signals
• axon terminal communicates with neighboring cells through the synapse

Question 5

How does saltatory conduction works?

Answer 5

Myelination acts as electrical insulation.
Gaps between sheathes called nodes or
Ranvier. Wave of sodium ions

Active excitation of the axonal membrane jumps
from node to node; this form of impulse
propagation is called saltatory conduction, which
allows impulses to travel faster.
Only in
Vertebrates

Question 6

Structure of the charged membrane:

Answer 6

Outside: Positive charge lots of sodium plus ions

Inside: Negative charge few potassium ions and negatively charged proteins

Resting membrane: -70mV

Polarized membrane: like a battery but the cell membranes seperate into two poles

Question 7

How is the membrane charged?

Answer 7

The Na+-K+ ATPase pump maintains the electrochemical
gradient establishing the -70 mv resting potential through primary active transport

Question 8

How does neurons meet the synapses?

Answer 8

• Molecules called neurotransmitters (like
  serotonin, dopamine and glutamate) convey the
  signal from the end of the axon to the
  postsynaptic target cell

● Neurotransmitters cause a change in the
electrical charge across the membrane of the
receiving cell, continuing the signal.

● Some neurons synapse with other cell types that
produce a response—for example, muscle cells
or secretory cells.

Question 9

Synapses neuron communication: excitatory vs. inhibitory

Answer 9

excitatory post synaptic potential
Neurotransmitters open ligand gated
Na+ channels and start an action potential

Inhibitory postsynaptic potential
Other neurotransmitters can make
the post synaptic membrane potential
more negative or hyperpolarized
through opening of ligand gate Cl- or
K+ channels.Gamma-aminobutyric acid (GABA) is
the chief inhibitory neurotransmitter.
It reduces ”excitability”… sold as a
dietary supplement .