chapter 5 NS Flashcards
Neurons/ Nerve cells-
send electrochemical impulses in response to stimuli received and to effect an action as a
result of stimuli- send and receive signals from the brain
neuroglia
Support and protect the neuerons
soma
cell body w/ a large nucleus
Axon
a long slender projection that conducts electrical impulses (action potential) away from the cell body.
Axon is surrounded by ________ froming the ______.
Schwann Cells
Myelin sheath
Dendrites
tree like structures that recieve messages from other neurons.
Axon terminal/ nerve ending
contians synaptic vesicles hilding neurotransmitters.
synapes
specialized junctions between nuerons
Neurons are classified into three broad types:
A. Sensory
B. Motor
C. interneurons
Sensory
triggered by physical (sound, touch, heat, and light) and chemical (smell and taste) inputs from your environment.
For ex, stepping on hot sand activates sensory neurons in the soles of your feet
→ neurons send a message to brain
→ makes you
aware of the heat.
motor
neurons play a role in movement, including voluntary and involuntary movements. These neurons allow the brain and spinal cord
to communicate with muscles, organs, and glands all over the body.
For ex, when eating, lower motor neurons in spinal cord send signals to smooth muscles in esophagus, stomach, and
intestines
→ muscles contract
→ allows food to move through GI tract.
Interneurons
are neural intermediaries found in brain and spinal cord, most common type of neuron, pass signals from sensory neurons
and other interneurons to motor neurons and other interneurons.
For ex, when you touch something hot, sensory neurons in fingertips send a signal to interneurons in spinal cord
→ interneurons
pass the signal on to motor neurons in your hand, which allows you to move your hand away. Other interneurons send a signal t o
the pain center in your brain, and you experience pain.
Nerve glue?
Neuroglia or glial cells or glia
nueroglia funsctions?
- Form myelin, which wraps around axons to speed up electric impulse conduction
- Provide nutrients to neurons, including oxygen
- Destroy pathogens
- Provide a general support structure on which neurons can sit
how is information transmitted?
Action potential
action potential
when the membrane potential changes rapidly, has 2 main parts: Depolarization → Negative to Positive
and Repolarization → Positive to Negative
nuerons have a potential difference of
-70 mV
Propagation of action potentials along myelinated axons
Saltory Conduction
Here the signal jumps from one node of Ranvier to the next node, increasing the conduction velocity of action potentials
Saltory Conduction
The uninsulated nodes of Ranvier are the only places along the axon where membrane depolarization and ion exchange occurs across the
axon membrane.
Saltory Conduction
Biological process by which a neuron communicates with a target cell across a synapse.
Synaptic Transmission
involves the release of a neurotransmitter from the pre-synaptic neuron, and
neurotransmitter binding to specific post-synaptic receptors.
Chemical Synaptic transmission
involves the transfer of electrical signals through gap junctions.
Electrical synapse transmission
Step 1 in Synaptic transmission ?
Action potential arrives at axon terminal
Step 2 in Synaptic transmission?
Voltage-gated Ca 2+ channels open
step 4 in Synaptic transmission?
CA2+ signals to neurotransmitter vesicles
Step 3 in Synaptic transmission ?
Ca 2+ enters the presynaptic neuron
step 5 in Synaptic transmission?
Vesiclces move to the membrane and dock
step 6 in Synaptic transmission?
Neurotransmitters released via exocytosis
Step 7 in Synaptic transmission?
Neurotransmitters bind to receptors
Step 8 in Synaptic transmission?
signal initited in postsynaptic cell
