Nervous Physiology 3 Flashcards
How many motor neurons connect the CNS to an organ in the autonomic nervous system?
2
Which types of tissue if controlled by the motor aspect of the ANS?
Smooth muscle and glandular tissue.
First neuron in the motor pathway of the ANS
Found in the lateral grey horn of the spinal cord. Called the preganglionic fiber. Is myelinated and type B.
Second neuron in the motor pathway of the ANS
Found in a ganglia. Called the post-ganglionic fiber and travels to the effector. Unmyelinated and type C.
Sympathetic preganglionic fibers
Are short because the ganglia are close to the vertebral column.
Sympathetic postganglionic fibers
Are long because the effectors are far away from the ganglia alongside the spinal cord.
Divergence
When a single sympathetic neuron may have 10-20 ganglionic neurons. Causes mass activation.
Parasympathetic preganglionic neurons
Long because the ganglia is far away from the spinal cord.
Parasympathetic postganglionic neurons
Short because the effector is close tot he ganglia.
Which cranial nerves carry parasympathetic preganglionic fibers?
3, 7, 9 and 10
SLUDD
Processes encouraged by the parasympathetic nervous system. Salivation, lacrimation, urination, digestion and defecation.
Paradoxical fear response
When escape is deemed impossible, causes fainting, urination and defecation due to vagal discharge on the heart.
Cholinergic neurotransmitters
Cause acetylcholine to be released.
Adrenergic neurotransmitters
Causes norepinephrine to be released.
Neurotransmitter released by all preganglionic fibers of the ANS
Acetylcholine
Neurotransmitter released by parasympathetic postganglionic fibers
Acetylcholine
Neurotransmitter released by sympathetic postganglionic fibers
Norepinephrine except for those directed to sweat glands and blood vessels of the skeletal muscle. These release acetylcholine.
Autonomic varicosities
Connection between autonomic fibers and target effectors. A swelling of the fiber that forms an extended network.
Short reflex
Reflex involving the direct stimulation of a postganglionic fiber by a sensory neuron. Occurs in the digestive system.
Long reflex
Reflex involving integration within the CNS.
Autonomic tone
The tendency of an organ to be governed by one division of the ANS over the other.
Central control over autonomic function comes from where?
The hypothalamus.
Amygdala
Group of nuclei in the medial region of the temporal lobe.
Function of the amygdala
In a strong emotional response, the amygdala will send information to the hypothalamus through the MFB, producing a sympathetic response.
Limbic lobe
Structures around the edge of the cerebrum. Includes the amygdala, hippocampus and cingulate gyrus. Connects to the hypothalamus.
Which nerve provides parasympathetic innervation to the digestive organs?
The vagus nerve.
Pre-vertebral ganglia
Sympathetic ganglia that lie close to the large abdominal arteries and anterior to the vertebral column.
Where does the adrenal medulla receive stimulation from?
Sympathetic pregnaglionic fibers
From where does the head receive its sympathetic innervation
The superior cervical ganglia.
Grey matter consists of what?
Cell bodies and dendrites.
White matter consists of what?
Axons and myelin
Tract
Bundle of axons within the CNS.
Nerve
Bundles of axons within the PNS.
Repairs can occur in the PNS so long as what conditions are met?
The cell body is intact, Schwann cells remain active and form a tube and the scar tissue does not form too rapidly.
