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Final (1) Ch. 14
pgs. 524-536 the ANS
Terms in this set (74)
**Although all body systems contribute, the stability of our internal environment depends largely on the ___ ___ ___, the system of motor neurons that innervates smooth and cardiac muscle and glands.
Autonomic Nervous System
*The ANS is also called the involuntary nervous system, which reflects its subconscious control, or the ___ ___ ___ ___, which indicates the location of most of its effectors
general visceral motor system
(i) The ANS uses a ___-____ ___ to reach its effectors
*In the ANS, the cell body of the first neuron, the ____ ____, resides in the brain or spinal cord
*the ____ ____ synapses with the second motor neuron in the ANS
*The ___ ___ (sometimes called the ganglionic neuron), is the second motor neuron in the ANS.
*The postganglionic's cell body is an ____ ____ outside the CNS
*In the ANS, the ____ ___, extends to the effector organ
(i) autonomic ganglia are ___ ganglia, containing the cell bodies of motor neurons
**All somatic motor neurons release ____ at their synapses with skeletal muscle fibers. The effect is always excitatory, and if stimulation reaches threshold, the muscle fibers contract
*Autonomic postganglionic fibers release 2 neurotransmitters: ____ secreted by most sympathetic fibers, and ACh secreted by parasympathetic fibers.
*The _____ ____ promotes maintenance functions and conserves body energy
*The ___ ___ mobilizes the body during activity in the ANS
*Parasympathetic and sympathetic divisions undergo ___ ___, the two divisions counterbalance each other to keep body systems running smoothly.
**The ____ ____, sometimes called the "rest and digest" system, keeps body energy use as low as possible, even as it directs vital "housekeeping" activities like digesting food and eliminating feces and urine.
**The activity of the ____ ____ (often called the fight-or-flight system) is evident when we are excited or find ourselves in emergency or threatening situations, such as being frightened by street toughs late at night.
a rapidly pounding heart, deep breathing; dry mouth; cold, sweaty skin; and dilated pupils are sure signs of ___ ____ system mobilization
sympathetic nervous system
The parasympathetic and sympathetic divisions differ in their sites of origin. _____ fibers originate in the brain, while ____ fibers originate in the thoracic and lumbar regions of the spinal cord.
**The parasympathetic division is also called the ____ ____ because its preganglionic fibers spring from opposite ends of the CNS--the brain stem and the sacral region of the spinal cord.
*The preganglionic axons extend from the CNS nearly all the way to the structures they innervate. There the axons synapse with postganglionic neurons located in ____ ____ that lie close to or within the target organs.
*______ fibers run in the oculomotor, facial, glossopharyngeal, and vagus cranial nerves. Their cell bodies lie in associated motor cranial-nerve nuclei in the brain stem
*The parasympathetic fibers of the ____ ____ innervate smooth muscles in the eyes that cause the pupils to constrict and the lenses to bulge--actions needed to focus on close objects.
oculomotor nerves (III)
*The cell bodies of postganglionic neurons are in the ___ ___ within the eye orbits
*The parasympathetic fibers of the ___ ___ stimulate many large glands in the head
facial nerves (VII)
*The preganglionic fibers synapse with postganglionic neurons in the _________ ______ just posterior to the maxillae
*The preganglionic neurons that stimulate the submandibular and sublingual salivary glands originate in the superior salivatory nuclei of the pons. They synapse with postganglionic neurons in the ____ ___, deep to the mandibular angles
*The parasympathetics in the glossopharyngeal nerve (IX) originate in the inferior salivatory nuclei of the medulla and synapse in the ___ ___, located just inferior to the foramen ovale of the skull.
*the two ___ ___ account for about 90% of all preganglionic parasympathetic fibers in the body
vagus nerves (X)
*___ ___ provide fibers to the next and to nerve plexuses (interweaving networks of nerves) that serve virtually every organ in the thoracic and abdominal cavities
vagus nerves (X)
*As the vagus nerves pass into the thorax, they send branches to the ___ ___ supplying fibers to the heart that slow heart rate
*As the vagus nerves pass into the thorax, they send branches to the ___ ___ serving the lungs and bronchi
*As the vagus nerves pass into the thorax, they send branches to the ___ ___ supplying the esophagus
*The ___ part of the parasympathetic division serves the pelvic organs and the distal half of the large intestine.
*The _____ division is anatomically more complex than the ____ division, partly because it innervates more organs. It supplies not only the visceral organs in the internal body cavities but also all visceral structures in the superficial (somatic) part of the body
*All preganglionic fibers of the sympathetic division arise from cell bodies of preganglionic neurons in spinal cord segments t1-L2. For this reason the sympathetic division is also referred to as the ____ ____
*The numerous preganglionic sympathetic neurons in the gray matter of the spinal cord form the ____ ___
*After leaving the cord via the central root, preganglionic sympathetic fibers pass through a ___ ___ ___ to enter an adjoining sympathetic trunk ganglion forming part of the sympathetic trunk (or sympathetic chain).
white rams communicans
*Looking like strands of glistening white beads, the ___ ___ flank each side of the vertebral column
The ___ ___ consist of the sympathetic ganglia and fibers running from one ganglion to another
(i) The sympathetic trunk ganglia are also called ___ ___ or paravertebral ganglia
*The preganglionic axon passes through the trunk ganglion and emerges from the sympathetic trunk without synapsing. These preganglionic fibers help form several splanchnic nerves and synapse in ___, or pre vertebral, ___ located anterior to the vertebral column. unlike sympathetic trunk ganglia, the collateral ganglia are neither paired nor segmentally arranged
*When synapses are made in sympathetic trunk ganglia, the postganglionic axons enter the central rams of the adjoining spinal nerves by way of communicating branches called ___ ___ ____.
gray rami communicantes
*Sympathetic preganglionic fibers serving the head emerge from spinal cord segments T1-T4 and ascend the sympathetic trunk to synapse with postganglionic neurons in the ___ ___ ___
superior cervical ganglion
*This ganglion contributes sympathetic fibers that run in several cranial nerves and in the upper three or four cervical spinal nerves.
superior cervical ganglion
*Postganglionic fibers emerging from the middle and inferior ___ ___ enter cervical nerves C4-C8. Some of these fibers innervate the heart via the cardiac plexus, and some innervate the thyroid gland, but most serve the skin
*Most of the preganglionic fibers from T5 down synapse in collateral ganglia, and so most of these fibers enter and leave the sympathetic trunks without synapsing. They form several nerves called ___ ___, including the thoracic splanchnic nerves and the lumbar and sacral splanchnic nerves
*The ___ ___ contribute to a number of interweaving nerve plexuses known collectively as the abdominal aortic plexus, which clings to the surface of the abdominal aorta.
*Sympathetic preganglionic fibers from T5 to L2 innervate the ____
The most important of these ganglia are the CELIAC, SUPERIOR MESENTERIC, and INFERIOR _____, named for the arteries with which they most closely associate. Postganglionic fibers issuing form these ganglia generally travel to their target organs in the company of the arteries serving these organs
(i) for the most part, sympathetic fibers ___ the activity of muscles and glands in the abdominopelvic visceral organs.
(i) When stimulated by preganglionic fibers, the medullary cells secrete ___ and ___ into the blood, producing the excitatory effects we have all felt as a "surge of adrenaline"
norepinephrine and epinephrine (also called noradrenaline and adrenaline)
** ___ ___ __, which send information concerning chemical changes, stretch, and irritation of the viscera, are the first link in autonomic reflexes
visceral sensory neurons
**___ ___ ___ have essentially the same components as somatic reflex arcs--receptor, sensory neuron, integration center, motor neuron and effector. However, a key difference is that this reflex arc has two neurons in it component.
visceral reflex arcs
Nearly all ___ and ____ fibers so far are accompanied by afferent fibers conducting sensory impulses from glands or muscles
sympathetic and parasympathetic
**The major neurotransmitters released by ANS neurons are ____ and ____
acetylcholine and norepinephrine
____, the same neurotransmitter secreted by somatic motor neurons, is released by all ANS preganglionic axons and all parasympathetic postganglionic axons at synapses with their effectors
**Fibers that release acetylcholine are called ___ ___
*Most sympathetic postganglionic axons release NE and are called ____ ___.
*The two types of ____ receptors are named for drugs that bind to them and mimic acetylcholine's effects
*____ receptors respond to nicotine
*the two types of cholinergic receptors
nicotinic and muscarinic recptors
*____ receptors, the other set of ACh receptors, can be activated by the mushroom poison muscarine.
*____ receptors are found on the sarcolemma of skeletal muscle cells at neuromuscular junctions
___ receptors are found on all postganglionic neurons, both sympathetic and parasympathetic
____ receptors are found on the hormone-producing cells of the adrenal medulla
*There are two major classes of adrenergic (NE-binding) receptors: ___ and ___
alpha and beta
*Knowing the locations of the ___ and ___ receptor subtypes allows clinicians to prescribe specific drugs to stimulate or inhibit selected target organs
cholinergic and adrenergic
(i)an anticholinergic drug that blocks muscarinic ACh receptors. It is routinely administered before surgery to prevent salivation and dry up respiratory system secretions. also used to dilate pupils
(i) the anti cholinesterase drug ____ inhibits the enzyme acetylcholinesterase that breaks down ACh. This allows ACh to accumulate in synapses. It is used to treat myasthenia gravis
(i)Hundreds of over the counter drugs used to treat colds, coughs, allergies, and nasal congestion contain ____. This contracts the blood vessels in the nasal mucosa, inhibiting secretions
(i) Most visceral organs receive ___ ___ from both the parasympathetic and sympathetic divisions.
*With few exceptions, the vascular system is entirely innervated by sympathetic fibers that keep the blood vessels in a continual state of partial constriction called ____ or _____, tone
sympathetic or vasomotor tone
When blood pressure is low, the ____fibers fire more rapidly, causing constriction. when blood pressure is high, sympathetic fibers fire less rapidly and vessels dilate.
*Alpha-blockers, drugs that block the responses in these ____ ___, are sometimes used to treat hypertension (high blood pressure).
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