Download Autonomic Nervous System: Function, Regulation, and Innervation and more Quizzes Philosophy of psychiatry in PDF only on Docsity!
Autonomic function
refers to systems that regulate and maintain the homeostasis or constant environment of the body in an unconscious or automatic fashion TERM 2
Types of regulation
DEFINITION 2 slow acting long termrapid reactions to acute changes TERM 3
Two mechanisms of regulation
DEFINITION 3 humeral and neuralboth under CNS control TERM 4
Humoral
DEFINITION 4 homeland security -endocrine (i.e. uses a circulatory system) responses develop slowly and have prolonged effects TERM 5
Neural
DEFINITION 5 rapid reaction force- tends to act rapidly and have short term effects on viscera.
Combination of humoral and
neural
The adrenal medulla is neural activated but uses an endocrine effector arm. TERM 7
Composition of the ANS
DEFINITION 7 comprised of the central and peripheral neural components of autonomic regulation TERM 8
ANS does what?
DEFINITION 8 is responsible for the rapid regulation of activity in cardiovascular, respiratory, digestive, urinary and reproductive organs. TERM 9
ANS is described as what kind of system?
DEFINITION 9 The ANS is described as a visceral motor system, but does have some sensory components that are essential to its function. TERM 10
The visceral motor pathways are divided into
what three primary subdivisions?
DEFINITION 10 SympatheticParasympatheticEnteric
Blood vessels control
With the exception of the coronary arteries, vasoconstriction (produced by the nervous system) is sympathetically stimulated.Vasomotor control over vessels of the body wall are controlled by the sympathetic system alone.The reduction of blood flow to a gland will generally reduce or change the nature of glandular secretions (e.g. saliva as watery or thick).In deep muscles, sympathetic stimulation produces vasodilation.All autonomic effects on blood vessels are produced by action on vascular smooth muscle. TERM 17
For both sympathetic and parasympathetic
systems, there are at least two what?
DEFINITION 17 neurons involved in the connections between the CNS and peripheral targets TERM 18
Where is the first neuron?
DEFINITION 18 The first is in the CNSThe neuron in the CNS is referred to as a preganglionic autonomic neuronIts thinly myelinated axon is called the preganglionic fiber or axon. It contacts neurons located in an autonomic ganglion in the body. TERM 19
Where is the second neuron?
DEFINITION 19 second a peripheral autonomic ganglia(inappropriately called the postganglionic neurons) sends out an unmyelinated axon (postganglionic fiber or axons) to the visceral effector cell TERM 20
Where are sympathetic ganglion located?
DEFINITION 20 located near the CNS (short preganglionic axon, long postgangionic axon.
Where are parasympathetic ganglion located?
Parasympathetic autonomic ganglia are generally located near or in the target organ (long preganglionic axon, short postganglionic axon TERM 22
The sympathetic ganglia include what?
DEFINITION 22 the prevertebral and paravertebral ganglia TERM 23
What controls those ganglia?
DEFINITION 23 They are under the control of neurons located in the spinal cord, which in turn are under the influence of neurons in the brainstem and hypothalamus. TERM 24
Where are the sympathetic ganglia located?
DEFINITION 24
- The sympathetic chain (trunk, paravertebral ganglia). These ganglia contain postganglionic neurons for innervation of the body wall and thoracic viscera.2. prevertebral ganglia associated with the abdominal aorta and its larger branches). These ganglia contain postganlionic neurons that innervate abdominal viscera and partly pelvic viscera TERM 25
Preganglionic axons from neurons in the
spinal cord exit where?
DEFINITION 25 via ventral roots at spinal segments T1 through L2 (hence - thoracolumbar) and enter the sympathetic trunk via the white communicating ramus (myelinated axons).
In the abdominal and pevlvic cavities,
postganglionic prevertebral sympathetic
axons follow what?
the course of arteries to supply innervation to the abdominal viscera and also have control over their blood flow. TERM 32
Large increases in sympathetic activity are
created by what?
DEFINITION 32 intense excitement or exertion TERM 33
effects of sympathetic activity
DEFINITION 33 increased HR, BP, blood to skeletal muscles, blood glucose levels, sweating, pupil diameterdecreased gut mobility, digestive gland secretion, blood to abdominal viscera and skin TERM 34
The Parasympathetic (craniosacral system)
innervation
DEFINITION 34 is much more restricted in its distribution than in the sympathetic division.Preganglionic neurons are located in the brainstem nuclei of Cranial Nerves III, VII, IX and X and in sacral spinal segments S2 to S4, TERM 35
Parasympathetic Innervation of the Head
DEFINITION 35 Preganglionic parasympathetic axons from the cranial nerves that innervate the head begin in their respective cranial nerves, but progressively re distribute to join parts of the trigeminal nerve (CNV) to their targets.Their targets in the head are parasympathetic postganglionc neurons located in discrete ganglia (Ciliary, pterygopalatine, otic, submandibular)
Preganglionic parasympathetic Innveration of
the viscera in body cavities is via what?
the vagus nerve (CN X) and from neurons located in the spinal cord from S2 to S4These neurons contact cells typically scattered in nerve plexuses in the target organ (terminal or intramural ganglia) or wall of the gut. TERM 37
Cranial nerve X provides what?
DEFINITION 37 parasympathetic visceromotor function influences to the thoracic and abdominal viscera up to the first two thirds of the colon. TERM 38
The final third of the colon, the pelvic viscera
and genitalia receive parasympathetic motor
function through what?
DEFINITION 38 the sacral spinal cord (S2-S4). TERM 39
examples of visceral sensory
information
DEFINITION 39 Examples include sympathetic splanchnic and cardiac nerves, the parasympathetic division of the vagus nerve and the pelvic nerves. The cell bodies of all sensory neurons that conduct information from viscera (1st order) are located in peripheral ganglia, either dorsal root ganglia or cranial nerve ganglia. TERM 40
Autonomic sensory information can be
generally divided into what?
DEFINITION 40 nociceptive (painful) and physiological (visceral stretch, touch and specialized receptors).
Non- painful visceral sensation goes to the
CNS through what?
though the sacral spinal cord (S2-4) and to the brainstem in cranial nerves VII, IX, and X. TERM 47
non-painful visceral sensation used for
what?
DEFINITION 47 These sensations are used to monitor visceral functions and body homeostasis on a continuous basis.Sensation from physiological receptors may be conscious or unconscious, but is generally not painful. These sensations are used to mediate normal visceral reflexes TERM 48
specialized receptors of parasymp receptors
DEFINITION 48 include baroreceptors, chemoreceptors osmoreceptors and internal thermal receptors TERM 49
chemoreceptors
DEFINITION 49 are responsive to changes in arterial oxygen and carbon dioxide, blood pH, and to some drugs TERM 50
baroreceptors
DEFINITION 50 are responsive to changes in arterial blood pressure
Osmoreceptors
are responsive to changes in blood osmolarity TERM 52
Thermal receptors
DEFINITION 52 response to changes in blood temperature. TERM 53
Example of Autonomic Reflex Function
DEFINITION 53 The baroreceptor reflex is a basic physiological effect to control blood pressure and heart rate.Glossopharyngeal and vagal afferents report blood pressure and oxygenation to the brainstem. In the presence of low blood oxygen or pressure, the heart rate will be stimulated (sympathetic). The vagus influence on the heart will be inhibited. TERM 54
The sympathetic and parasympathetic
divisions have their greatest anatomic
overlap where?
DEFINITION 54 in the regulation of the viscera TERM 55
In the abdominal viscera, they exert general
influences over a third neuronal system
called what?
DEFINITION 55 the enteric nervous system
central autonomic network.
The stimuli from visceral or other sensation can trigger strong autonomic responses after being perceived by cerebral cortex. TERM 62
what part of the brain has direct control over
the ANS responses?
DEFINITION 62 Higher autonomic centers such as those in the hypothalamus and to some extent the brainstem TERM 63
Conscious perceptions generated in cerebral
cortex can regulate the activity where?
DEFINITION 63 central autonomic centers in the hypothalamus which in turn regulates cranial nerve and spinal cord mediated autonomic activity TERM 64
A classic example of autonomic control as a
result of central nervous system
interpretation
DEFINITION 64 the opposing influence of the sympathetic and parasympathetic divisions on heart rate. Sympathetic stimulation via cardiac nerves increases the rate of heart beat while parasympathetic stimulation the vagus nerve slows it. TERM 65
All of the signals of the autonomic nervous
system to and from target organs is
dependent upon the process of what?
DEFINITION 65 largely chemically mediated neurotransmissionThis involves both neurotransmitters and their receptors
In the sympathetic division, the
neurotransmitter used by preganglionic
neurons is what?
primarily acetylcholine TERM 67
most postganglionic neurons use what NT?
DEFINITION 67 norepinepherine TERM 68
A few postganglionic sympathetic neurons
use acetycholine example
DEFINITION 68 sweat gland innervation TERM 69
For the parasympathetic system, both
preganglionic and postganglionic
parasympathetic neurons use what as their
primary NT?
DEFINITION 69 acetycholineThe fact that preganglionic neurons of both autonomic divisions use acetylcholine as a neurotransmitter indicates that drugs or other agents (toxins, etc.) that affect or mimic acetylcholine may have broad autonomic effects. TERM 70
Receptors for acetylcholine are broadly
classified as what?
DEFINITION 70 nicotinic and muscarinic, with several subclasses of each.
For example, activation of a1 receptors on
vascular smooth muscle by sympathetic
stimulation will produce what?
vasoconstriction (excitatory response) TERM 77
activation of b2 receptors result in what?
DEFINITION 77 in relaxation (inhibitory response).
