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Chapter 11: Autonomic and Motor Systems
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24
Physiology
Undergraduate 2
10/16/2013

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Term
Dual innervation
Definition
Both branches of the autonomic nervous system innervate most organs
Term
Another name for the autonomic nervous system is
Definition
Involuntary nervous system
Term
The primary function of the autonomic nervous system is
Definition
To regulate the function of effector organs so as to maintain homeostasis
Term
Preganglionic neurons
Definition
Travel from the CNS to the ganglia
Term
Postganglionic neurons
Definition
Travel from the ganglia to the effector organs
Term
Lateral horn
Definition
Region from which the preganglionic neurons originate
Term
What are the three ways in which preganglionic and postganglionic neurons can be arranged in the sympathetic nervous system?
Definition
1. Preganglionic neurons synapse with the postganglionic neurons sympathetic chain which connect to the effector organ
2. Preganglionic neurons innervate the chromaffin cells of the adrenal medulla, stimulating the release of epinephrine into the blood.
3. Preganglionic neurons synapse with postganglionic neurons in structures called collateral ganglia between the CNS and effector organs
Term
What is the most important nerve of the parasmpathetic nervous system?
Definition
Cranial Nerve 10, also known as the Vagus nerve. This nerve originates in the medulla oblongata and innervates much of the viscera, including the lungs, heart, stomach, small intestines and liver
Term
What are the two primary neurotransmitters in the peripheral nervous system?
Definition
Acetylcholine and norepinephrine
Term
Adrenergic
Definition
Neurons that release norepinephrine
Term
Where are nicotinic cholinergic receptors found?
Definition
Cell bodies and dendrites of sympathetic and parasympathetic postganglionic neurons, on chromaffin cells and on skeletal muscle cells
Term
Where are muscarinic cholinergic receptors found?
Definition
Effector organs of the parasympathetic nervous system such as the heart, smooth muscles controlling the diameter of pupils and smooth muscles in the digestive tract
Term
What happens when acetylcholine binds to its receptors?
Definition
Cation channels open, allowing sodium to diffuse into the cell and potassium to diffuse out of the cell
Term
What is the only effector organ controlled by the somatic nervous system?
Definition
Skeletal muscle
Term
What is the only type of efferent neuron in the somatic nervous system?
Definition
Motor neurons which innervate skeletal muscle
Term
Where do motor neurons originate?
Definition
The ventral horn of the spinal cord
Term
What is another name for muscle cells?
Definition
Muscle fibers
Term
Motor unit
Definition
A motor neuron plus all the muscle fibers it innervates
Term
Neuromuscular junction
Definition
A central region of a skeletal muscle fiber where each branch of a motor neuron synapses
Term
Terminal boutons
Definition
Axon terminals of the motor neuron that sotre and release acetylcholine
Term
What is the only neurotransmitter of the somatic nervous system?
Definition
Aceytlcholine
Term
Motor end plate
Definition
Specialized region of a muscle fiber's plasma membrane which contains invaginations containing large numbers of nicotinic cholinergic receptors.
Term
What is the function of acetylcholinesterase found in the invaginations of the motor end plate?
Definition
Terminates the excitatory signal, allowing the muscle fiber to relax
Term
End-plate potential (EPP)
Definition
A depolarization produced by sodium flowing into the muscle fiber.
EPP's are usually strong enough to depolarize the muscle fibers to threshold, generating an action potential, triggering contraction of the muscle fiber
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