BIO 1012 Anatomy and Physiology Lab
The Nervous System II: Anatomy Review
1. The somatic nervous system stimulates __Smooth__ muscle. The autonomic nervous system stimulates _Skeletal___ muscle, __Cardiac___ muscle, and _Glands___.
2. The autonomic nervous system (ANS) consists two divisions, each innervating the effector organs. The sympathetic nervous system (SNS) generally speeds up everything except digestion. The parasympathetic nervous system (PNS) generally slows down everything but digestion. Signals from the SNS cause the heart rate to _rise___, while signals from the PNS cause the heart rate to _slow____.
Signals from the SNS cause smooth muscles of the intestine to _excite_ contractions, while signals from the PNS cause these muscles to slow__ contractions.
Signals from the SNS also cause the adrenal gland to secrete__ epinephrine and norepinephrine. 3. Neurons can excite or inhibit another neuron.
Exciting another neuron will increase the chances of a/an __excites___ in the second neuron. Inhibiting another neuron will make the chances of a/an __inhibits______ less likely. 4. Axons from one neuron can synapse with the dendrites or soma of another axon. These synapses are called _axosomatic___ (on dendrites) and __axodendritic____ (on soma). They carry input signals to the other neuron.
Axons from one neuron can synapse with the axon terminal of another neuron. These synapses are called ____axoaxonic___, and they regulate the amount of _chemical transmitters___ released by the other neuron.
5. The electrical synapse:
Electrical current flows from one neuron to another through __gap junction_. These synapses are always (excitatory or inhibitory).
Advantages of the electrical synapses:
1. _fast_ signal conduction
2. __synchronized__ activity for a group of neurons.
6. The chemical synapse:
Chemical synapses are not as fast as electrical but are the most common type of synapse. A chemical, called a neurotransmitter__, is released from the sending neuron and travels across the_synaptic cleft_(a gap between the neurons) to the receiving neuron. Advantages of the chemical synapse:
1. The signal can be either _excitatory__ or _inhibitory__. 2. The signal can be __modified_ as it passes from one neuron to the next. 7. The neuron conducting the impulse toward the synapse is called the _presynaptic__ neuron. The axon terminal contains _synaptic__ __vesicles__ filled with _neurotransmitters__. An action potential in the axon terminal of the __postsynaptic_neuron causes the chemical transmitter ___neurotransmitter___ to be released. It diffuses across the synaptic cleft and binds to receptors on the _postsynaptic_ membrane.
These receptors open __ion channels__. The movement of the charged particles causes an electrical signal called a __synaptic potential______.
The Nervous System II: Ion Channels
1. List four neurotransmitters that bind to ion channels, these neurotransmitters are called ______direct___-acting neurotransmitters.
2. a. The binding of ACh opens ion channels in the dendrites or cell body that permits both _Na+_ and ____K+___ to move through them.
b. Which ion would move into the cell? ____Na+__ out of the cell? ___K+______
c. Which ion has the greatest electrochemical gradient? ___Na+__ d. The net movement of these two ions would do what to the cell? __Makes the cell more positive______
e. This would be called an __Excited_____
postsynaptic potential, or _____EPSP_____.
3. a. An inhibitory postsynaptic potential (IPSP) causes a neuron to __Causes the cell to be more negative____.
b. An example of a neurotransmitter that causes an IPSP is __GABA__. c. What type of ions move into the cell in response to this neurotransmitter? _ C1-_.
4. a. Norepinephrine binds to a receptor that is separate from the ion channel. This is known as a/an ____indirect____ - acting...
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