Autonomic nervous system.of neurological pdf

Nervous System

2. The autonomic nervous system is the part of the peripheral nervous
system, have a complex neural network, working in concert with the
endocrine system and various nuclei in the brainstem, regulates vital
functions that are necessary for the maintenance of the internal
environment (homeostasis), including:
respiration
circulation
metabolism
body temperature
water balance
digestion
secretion, and reproductive function.
The designation “autonomic” is derived from the fact that these
functions are controlled by unconscious (involuntary) mechanisms.
This system is the primary mechanism in control of the “flight-or-
fight” and “rest and digest” response.
Its role is mediated by two different components.

5. Divides into:
1. Above segmental
Hypothalamus
Limbic-reticular system
2. Segmental part
Sympathetic
Parasympathetic
Sympathetic (thoraco-lumbar outflow):
-Lateral horn C8-L2 of spinal cord (C8-Th1 ganglion-lesion causes
Horner syndrome)
-Sympathetic trunk 20-22 ganglions
Parasympathetic (cranio-sacral outflow):
-Cranial part (III, VII, IX, X cranial nerves)
-Sacral part
Lateral horn S2-S4 (pelvic organ)

7. The hypothalamus is the hierarchically uppermost regulatory organ
(“head ganglion”) of the autonomic nervous system.
It plays the leading role in a wide variety of regulatory circuits for vital
bodily functions such as
temperature
heart rate
blood pressure
respiration
food and water intake.
These regulatory functions are carried out largely independently of any
conscious thought on the part of the individual, i.e., autonomically.
The hypothalamus also regulates important hormone systems through
the hypothalamic- pituitary axis and coordinates the interaction of the
endocrine and autonomic nervous systems.
Hypothalamus include 3 zones:
Paraventricular zone-neuroendocrine control via connections to pituitary
Medial zone-thermoregulation, osmoregulation, food intake, response
to stress
Lateral zone-arousal behavior, sleep wake cycle

8. The autonomic nervous system is composed of two
complementary systems:
the sympathetic nervous system and
the parasympathetic nervous system, whose effects are
generally antagonistic to each other.
The efferent fibers of both systems mainly innervate the
smooth muscle of the viscera, blood vessels, and glands and
are thus commonly called visceral efferent (visceromotor)
fibers.
The final efferent pathway of both the sympathetic and the
parasympathetic nervous systems consists of two neurons in
series. The cell body of the first (preganglionic) neuron lies
within the central nervous system, while that of the second
(postganglionic) neuron is found in a peripheral ganglion.

9. The first neurons of the sympathetic nervous system lie in the thoracic and
lumbar segments of the spinal cord (intermediolateral cell column, T1-L2); for
this reason, the sympathetic nervous system is sometimes called the
thoracolumbar system.
Some of the first neurons of the parasympathetic nervous system are found in
the nuclei of cranial nerves III, VII, IX, and X, while the remainder are found in
the lateral horns of the sacral segments of the spinal cord (pelvic
parasympathetic system, S2-S4). Thus, the parasympathetic nervous system is
sometimes called the craniosacral system.
The second neurons of the sympathetic nervous system are arranged in
prevertebral and paravertebral chains of ganglia (the sympathetic chains),
while those of the parasympathetic nervous system generally lie in the walls of
the innervated organs (intramural ganglia).
The first neurons of both systems use acetylcholine as their neurotransmitter.
The second neurons of the parasympathetic nervous system also use
acetylcholine as their neurotransmitter (a further alternative name for the
parasympathetic nervous system is, therefore, the cholinergic system).
The neurotransmitter of the postganglionic sympathetic neurons, however, is
norepinephrine (adrenergic system). The sweat glands are an exception to this
rule: the second sympathetic neuron innervating them is cholinergic, like a
second neuron in the parasympathetic nervous system.

12. Responsible for homeostatic control like
blood pressure
body temperature regulation
Urinary function
Pupil size
Sweating, sexual function & digestion
Regulates the activities of Cardiac muscle, smooth muscle,
and glands.

14. Stimulation of the rostral hypothalamus induces
increased parasympathetic activity, including:
reduction of the cardiac minute volume
hypotonia
slowing of the heartbeat
reduction of the respiratory volume
lowering of the basal metabolic rate
vasodilatation
sweating
salivation
contraction of the bladder
reduced secretion of epinephrine
increased peristalsis
pupillary constriction.

15. Stimulation of the caudal hypothalamus, on the other hand, induces
increased sympathetic (ergotropic) activity, including:
a rise in blood pressure
acceleration of the heartbeat
increased blood supply to the skeletal muscle and lungs
vasoconstriction in blood depots such as the capillary bed of the digestive tract
decreased blood supply to the abdominal viscera
increased respiratory volume
a rise in the blood glucose level
inhibition of peristalsis
urinary retention
increased secretion of epinephrine
widening of the palpebral fissure
pupillary dilatation.
A mass reaction thus occurs in the entire body, directed toward physical exertion
and therefore enabling the whole organism to deal optimally with situations of
attack and stress.
While the sympathetic (ergotropic) reaction is directed toward physical exertion,
the parasympathetic (trophotropic) reaction is directed toward rest and recovery.

16. Sympathetic nervous system
Sympathetic innervation of heart and lungs. Postganglionic fibers from
the cervical and upper four or five thoracic ganglia run in the cardiac
nerves to the cardiac plexus, which innervates the heart. Pulmonary
nerves innervate the bronchi and lungs.
Sympathetic innervation of the abdominal and pelvic organs.
Preganglionic fibers arise in thoracic segments T5 through T12 and
travel, by way of the greater and lesser splanchnic nerves, to the
unpaired prevertebral ganglia (the celiac, superior mesenteric, and
inferior mesenteric ganglia), which are located along the aorta at the
levels of origin of the correspondingly named aortic branches.
Adrenal medulla.
The adrenal medulla occupies a special position in the sympathetic
nervous system. It is analogous to a sympathetic ganglion, in that it is
directly innervated by preganglionic fibers. These fibers form synapses
onto modified second neurons within the adrenal medulla, which, rather
than possessing an axon, secrete epinephrine and norepinephrine into
the bloodstream. Sympathetic activation induces the adrenal medulla to
secrete epinephrine and norepinephrine, which then exert sympathetic
effects in the periphery. This is particularly important under conditions of
stress.

17. Parasympathetic nervous system
Parasympathetic innervation of the head. The cell bodies of the
preganglionic neurons lie in various brainstem nuclei, and their axons are
found in cranial nerves III, VII, IX, and X. The preganglionic fibers travel to
a number of ganglia that lie very close to their respective end organs (the
ciliary, pterygopalatine, submandibular, and otic ganglia).
 Westphal nucleus is a part of oculomotor nerve (III) in midbrain-sends
preganglionic axons that occupy peripheral portion of the oculomotor
nerve and synapse on the neurons of ciliary ganglion in the orbit. These
neurons innervate iris and ciliary muscles. Eliciting pupil constriction,
accommodation of eye.
 Superior salivatory nucleus (in Pons)
Projects via facial nerve (VII) to sphenopalatine ganglion, which innervates-
lacrimal gland (lacrimation), cerebral blood vessels (vasodilatation); to
submandibular ganglion-secretomotor &vasodilator inputs to
corresponding salivary glands.
Inferior salivatory nucleus (in Medulla oblongata)
Sends axons via glossopharyngeal (IX) nerve. Synapse on Otic ganglion.
Stimulate parotid gland secretion.

18. Parasympathetic innervation of the thoracic and abdominal organs.
Fibers of Vagus nerve (X) innervate visceral organs of the thorax and most of the abdomen
Stimulates-digestion, reduction in heart rate and blood pressure
Preganglionic cell bodies located in dorsal motor nucleus in the medulla
Postganglionic neurons (neurons are found in autonomic plexuses located immediately adjacent
to their end organs, or else within the bowel wall (myenteric plexus of Auerbach, submucosal
plexus of Meissner). Confined within the walls of organs being innervated.
Vagus innervates heart, respiratory tract and entire gastrointestinal tract except descending
colon and rectum
Most vagal preganglionic neurons-situated in dorsal motor nucleus of vagus provides input to
GIT and respiratory tracts, heart
Vagal preganglionic output to heart-neurons in ventrolateral portion of nucleus ambiguous.
Vagus-cardioinhibitory, visceromotor and secretomotor effects.
Parasympathetic innervation of the pelvic organs and genitalia.
Arises from neurons of sacral preganglionic nucleus located in lateral gray matter of spinal
segments S2-S3
Their axons pass via ventral roots of pelvic splanchnic nerves which join inferior hypogastric
plexus
Innervate colon, bladder, sexual organs
Parasympathetic output-contraction of bladder detrusor muscle & circular smooth muscle of
rectum
Sacral parasympathetic output elicits
Vasodilatation of cavernous tissue of penis required for penile erection, whereas sympathetic
output controls ejaculation.

21. Clinical Symptoms of Sympathetic Lesion
Horner’s syndrome
lesions affecting the ciliospinal center, the cervical sympathetic
chain (cervicothoracic ganglion), or the autonomic plexuses
along the blood vessels of the head and neck cause ipsilateral
Horner’s syndrome:
-Constriction of pupil (Miosis)
-Drooping of upper eyelid (Ptosis)
-Reduced prominence of eye (Enophthalmous)
-Anhidrosis (decreased sweating)

22. Diseases of the central nervous system
-Multiple system atrophy
-Parkinson’s disease
-Trauma
-Vascular diseases
-Neoplastic diseases
-Metabolic diseases (Cobalamin deficiency and others)
-Multiple sclerosis
-Medications
Diseases of the peripheral nervous system
-Diabetes
-Uremia
-Alcoholism

23. 1. General observation
Body built
State of nutrition and any abnormal configurations
The skin and mucous membrane, perspiration
Hair and nails
Salivation & lacrimation
Pay attention to color of skin (pallor, hyperemia, marble color,
greasiness of skin, acrocyanosis, hyperkeratosis, dryness,
hyperhidrosis, edema, bed sores), hair (alopecia, hirsutism, grey-
haired), nails (cross lines, fragility, deformation, thickening).
Examination of pulse asymmetry
Vascular reflexes from skin. Local dermographism is tested hatching
irritation of skin with dull-edged thing, the response is white line (white
dermographism).
If the examiner irritates with great strain, in 5-15 seconds white line
appears that is present within period of time from several minutes up to
several hours (red dermographism).

24. Reflexive dermographism is examined by hatching irritation of skin
with sharp-edged thing, after 5-30 seconds the response is pink-
reddish line with uneven borders, its width is 1-3 cm preserving
within 0,5-10 minutes
Pilomotor reflex is caused by pinching or cold irritation of shoulders or
occiput skin, the response is goose-flesh skin of ipsilateral side of
body.
Sweat examination is conducted by observation and touching of skin
also the iodine-starch test is used (Minor test). The patient skin is
covered with mixture of spirit and castor oil (iodine-1,5; castor oil-
10,0; spirit-90ml). After skin drying up it is covered with starch
powder. Then patient is placed in lighted room or patient takes 2
aspirin tablets or glass of hot tea. Pay attention to place where the
sweat is secreted, these places is violet-black colored. If the anhidrosis
the skin color does not change.
The skin temperature examination is tested by the method of electro
thermometry. Asymmetry of skin temperature is fixed. In the normal
individuals it does not exceed 0.5*.

25. Oculocardiac reflex is examined when the patient lies in supine
position with eyes closed. Before test the pulse is examined, then
examiner using his fingers compresses lateral parts of the patients
eyes without any force for 20-30 seconds. After 10 seconds,
continuing patient’s eyes, examiner registers pulse again. In normal
individuals the pulse is decreased (8-10 bites per minute).
Orthostatic reflex is believed positive when the pulse is increased after
standing up. Before the test patient should lie in quite room for 4-6
minutes. In normal individuals the pulse is increased (6-24 bites per
minute).
Clinostatic reflex is the opposite reflex. Pulse should be registered in
both tests after 15-25 seconds. In normal individuals the pulse is
decreased (4-6 bites per minute).
It is important to ask Patient about function of pelvic organs (normal,
retention or incontinence of urine and defecation, infertility, changed
libido and others).