Metasympathetic nervous system (MNS)
It governs such structures as:
1) smooth muscles;
2) epithelium absorbing:
3) epithelium secreting;
4) local circulation;
5) local endocrine elements;
6) local immune elements.
MNS is a complex of microrganglionar structures located in walls of inner organs possessing motor activity or automaty (stomach, intestine, urinary vesicle, heart, bronchi, uterus particularly uterus cervix). Intestine and heart MNS are studied the best.
Example: there are nervous plexuses in alimentary tract:
· intermuscular (of Auerbah);
· submucosal (of Meisner).
There are multiplied microganglii in every plexus. 3 types are differentiated in every microganglion:
· efferent – the axon of which is in direct contact with myocyte;
· afferent – their axons can be switched to efferent axons either axon can pass to paravertebral or prevertebral ganglii with switching to other neurons; also axons of these afferent neurons can come up to spine and to be swithed here to other neurons; thus, afferent impulsation coming from microganglii can be closed at different levels;
· associative neurons.
The similar picture is a characteristic of heart too.
1) central influencings transmittance – due to the fact that parasympathetic and sympathetic fibers can get into contact with metasympathetic system and thus make the correction of its influence on the management objects;
2) MNS can also perform role of separate and integrating structure id est there are ready reflectory arcs (afferent – associative – efferent neurons) in it.
There are term as “tone of VNS”: hypersympaticotony and hyperparasympaticotony.
Materials for auditory self-work.
4.1.List of study practical tasks necessary to perform at the practical class.
Materials and methods: bed, scale.
Investigation object: person.
Task 1. To perform pupils investigation
Pupils investigation better to carry out at day dispersed light of middle force. The investigated person sits on a chair with the face turned to the window, turns his head behind to the chair back and looks into ceiling (pupils are seen distinguishly). To mark pupils size and equality. To close one investigated person eye with hand (or scale) and to pay the attention to convergent size change and equality of other eye pupil, then to open it. To mark pupil reaction, to assess this reaction: alive, middle or weak.
Under norm at bright lighting the pupil is narrowed. In dark room, on the contrary, pupils are dilated. Dilated pupil’s state is called midriasis. The constant narrowing state – miosis.
Task 2. Reflex to eyes convergence
To determine investigated person pulse while his sitting for 15 seconds. Then the investigated person converges eyeballs axes for 15 seconds. After this it‘s necessary to determine pulse again. To make the conclusion.
Task 3. Vasomotor skin functions investigation
The investigated person rises one hand up (maximally) with divergent extensed fingers, other puts down for 30 sec. It is necessary to determine skin colour difference. Then the investigated person stretches both hands before himself for 30 seconds.
Under normal conditions hands colour must become equal in course of this time. At vegetative disfunction the skin colour leveling are retarded or becomes zyanotic for long, hand putted down or raised up becomes pale for 1 or more minutes.
Task 4. Dermographism
There exist 2 main dermographism types: white and red.
White dermographism is caused by light stroke skin irritation with acute subject. Under norm after 5-20 sec one can see white stripe (width - several millimeters), that disappears after 1-10 min.
If stroke irritation is performed stronger and slower, red stripe appears, that continues longer (for 1-1,5 min), sometimes even for 1-2 hours - red dermographism. It is necessary to pay the attention to oedema existance or absence (jugum, elevation).
At dermographism investigation you should mark:
· its character (white, red, mixed),
· stripe width,
· reaction duration.
When analyse you should take into account that red dermographism is maximally expressed on skin in upper body part, white one – on lower extremities.
On one’s face they can use another way - white spot (stain) probe- finger pressure to skin in course of 3 sec leads to white spot appearing for 2-3 sec. Doctor should remember that at hypersympathicotony white spot disappears slower.
Task 5. Erben’s reflex
To count investigated person’s pulse for 1 min while his staying. Then the investigated person must be turned forward or to squat down and to turn his head till chin touching with knees. Then counting pulse again for 1 min should be performed.
In healthy people pulse is retarded on 4-12 beats per minute. At hyperparasympathicotony pulse is very seldom; at hypersympathicotony - very quick.
Task 6. Abrams’ reflex
The investigated person lying on his back is trying to take his chin to his breastbone, but doctor impedes.
Under norm pulse is retarded more than on 12 per minute. It indicates to hyperparasympathicotony and is thought to be positive probe.
2. Literature recommended:
1. Lecture course.
2. Mistchenko V.P., Tkachenko E.V. Methodical instructions for dental students (short lecture course).-Poltava, 2005.-P. 13-17.
3. Mistchenko V.P., Tkachenko E.V. Methodical instructions for medical students (short lecture course).-Poltava, 2005.-P. 19-21.
4. Mistchenko V.P., Tkachenko E.V. Methodical instructions on Normal Physiology on practical classes for dental and medical students.-Poltava, 2005.-P. 53-55.
5. Ganong W.F. Review of Medical Physiology.-21st ed.-2003.-Section II.
6. Kapit W., Macey R.I., Meisami E. The Physiology Colouring Book: Harpers Collins Publishers, 1987.-P. 25.
7. Guyton – Ganong – Chatterjee. Concise Physiology /Ed. By Dr Raja Shahzad Gull: M.B.B.S., F.C.P.S., King Edward Medical College.-Lahore, 1998 (1st Edition).-P.315-320.
8. Guyton A.C. Textbook of Medical Physiology.-NY, 1992.-P.686-698.
3. Materials for self-control:
A. Control questions:
1. Vegetative nerves structural features:
· autonomic nervous system centres;
· synapses cholino- andrenoreceptive structures.
2. Autonomic nervous system functional features:
· vegetative innervation comparative characteristics;
· vegetative reflexes;
· autonomic nervous system influence on salivation.
3. Autonomic nervous system and behaviour reactions.
CONTENT MODULE 6: “HUMORAL REGULATION AND ENDOCRINE GLANDS IN VISCERAL FUNCTIONS REGULATION”
Humoral regulation, its factors, hormones action mechanism to the target cells, hormonal secretion regulation. Hypothalamic-hypophyseal system.
The topic studied actuality.
Organism visceral functions regulation is performed both by autonomic nervous system activity and with humoral mechanisms participance.
Humoral regulation is more ancient than nervous one. But it hasn’t lost its importance during evolution but it is developing and is improving. The biggest amount of human functions are triggered and corrected mainly by humoral but not nervous regulative mechanisms.
Only with knowledge the major regularities of humoral regulation one can understand developmental mechanisms of the biggest amount of organism pathological states, prevent their occurrence and achieve success at organism visceral systems therapy.
ORAL MUCOSA CHANGINGS AT SOME ENDOCRINOLOGICAL DISEASES
Odontogenesis is rather durable process. That is why the probability of its tissues injuries at endocrine pathology is quite high.
Adenohypophyseal, parathyroid and thyroid hormones participate in intrasecretory regulation of teeth growth and development. Neurohypophyseal somatotopine is major stimulator of dental tissues histogenesis. Teeth calcination is tightly connected with parathyroid hormone, teething – thyroid one.
Changings in oral cavity occur at endocrine glands hypofunction, hyperfunction or dysfunction. Stomatological expressions of some endocrine disorders are considered to have big diagnostic value. It is so because they are often manifesting. It means that they appear before general clinical symptoms. It should be mentioned that sometimes expressions on oral mucosa have many similar features with its changings at other, non-endocrinological diseases.
The mostly often oral mucosa injuries (catarrhal stomatitis, epithelium desquamation et al.) are found at sexual glands dysfunctions as a result of estrogens secretion disturbances.
Juvenile gingivitis. It is observed in fellows and girls in puberty, at menstrual cycle disorders. Oral mucosa changings are the result of gonadotropines action. Dentury anomalies, non-satisfactory oral cavity hygiene are among local predisposition factors. Gum mucosa is edematic, hyperemic and is bleeded easily. Gingival papillas, gum marginal limb hypertrophy is observed mainly in mandibular frontal teeth.
Gingivitis of the pregnant is also worthy to be described. It is developed because of pregnancy or its course is hardened during pregnancy. It is expressed in interdental papillas hypertrophy and sometimes also – of gum marginal limb. “Non-real” pockets are formed, gums get bleeded. Gravity of its course can be changed. Sometimes hypertrophied papillas reach teeth crown cutting limb or their masticatory surface. It causes pain and bleedings while eating. Gingivitis symptoms being present before pregnancy are hardened in the biggest cases. The gum is more often transformed into its normal state after labours but sometimes (at bad oral cavity hygiene, dental stone, bad dentures, denturing anomalies) and other local traumatizing factors gum hypertrophy is remained non-changed.
Knowledge about dental peculiarities of oral cavity changings at endocrinal disorders will encourage the early disease stage exposure as well as proper assessment the local expressions of general pathology and also adequate correction methods choosing.
Adenohypophyseal hypofunction. Retarded teething and child lacked development are observed at hypophyseal dwarfness. Teeth are formed properily because disorders are mainly expressed in the period when their germs formation was completed. Constant teeth pulpal chambers are wide, secondary dentin formation is retarded. Jaws bones are little. Skin hypoelasticity helps radial winkles appearance round mouth.
Adiposo-genital dystrophy is characterized by odontogenesis retardation in parallel to organism development retardation.
In a case of adenohypophyseal hyperfunction the biggest changing are observed at hypophyseal giantism and juvenile acromegaly.
Hypophyseal giantism is characterized by expressed odontogenesis acceleration. Crowns can be of usual size, but their roots are prolonged.
Juvenile acromegaly is described by distinct bright mandible development especially of its ascendant branch. Teeth can be of normal size, but their roots look shortened. Sometimes macroglossy is happened.
Endemic cretinism (hypofunction in childhood) is characterized by such changings in oral cavity as macroglossy, milky and constant teeth retarded development, enamel hypoplasy, predisposition to caries, lips size increasing, dryedness, cracks.
At juvenile mixedema in children both milky teeth teething and their changing period are retarded. Consequence of teething is disturbed. Dental tissues structures is remained non-changed. Tongue and lips are changed significantly in size, they are tended to be dry.
Thyroid hyperfunction is characterized by preliminary teething, tendency to caries, hypogevsia (gustatory sensations decreasing), multiplied sulcuses existence on tongue.
Parathyroid dysfunctions. Parathyroid main function is a regulation of calcium metabolism and inorganic phosphorus level. That is why these glands play important role in tooth solid tissues mineralization regulating.
Hypoparathyreoidism is the mostly often expressed in enamel hypoplasy. Constant incisives and first constant big molars are the most probable “targets” for injury. Hypocalciemia takes place during their mineralization.
Hyperparathyreoidism (Reklingauzen’s disease or fibrous osteodystrophy) is described by generalized skeleton injury due to osseal tissue reconstruction and its replacement with fibrous one. Progressive resorbtion of bone tissue takes place in pocket process together with teeth making wobbly and loosing.
Diabetes mellitus. Oral cavity changings are often manifesting.
Xerostomy is patients complaint from the very beginning of the disease. The manifestation is different in various patients. Hyperdypsia and hyperphagia (enforced thirst and appetite correspondingly) are also among symptoms. At examination: oral mucosa is weakly wet or dry, brilliant, with insignificant hyperemia. Dryedness is considered to be the result of dehydration. Dentist should keep in his mind that xerostomy is also observed at other diseases and states: Mikulich disease, sialoadenitis, sialodohitis, Shegren’s syndrome, nasal respiration disorders, nervous system disturbances and others.
Catarrhal stomatitis and glossitis – is the result of mucosa infectionning, easily possibility to be wounded because mucosa barrier function got significantly decreased, dysbacteriosis takes place. Hyposalivation encourages this. Patients complaint on pain when eating especially hot and solid food. Mucosa is dry, hyperemized, erosions and hemorhagias and other mechanical injuries are visual sometimes.
Fungal stomatitis, mycotic angular stomatitis. Fungal injury is rather stable. Mycotic angular stomatitis is the mostly often observed. Cracks covered by white-grey crusts are appeared in mouth angles. Fungal injuries are considered to be the result of dysbacteriosis on the background of organism resistance decreasing. Metabolic acidosis (due to pyruvate and lactate accumulation) helps to this.
Mucosa parestesia at diabetes occurs together with its dryedness. This symptome is also observed at alimentary tract and nervous system diseases. At diabetes mucosa burning is accompanied by skin itch in genitals area and other body areas.
Neuritis, trigeminal nerve neuralgia belong to neurological disorders observed at diabetes mellitus.
Patients have gustatory sensitivity disorders: decreasing to sweat, salty and to sour (in less extent). Taste sensitivity disorders are functional and they come to norm after treatment performed.
Trophyc changings can be present in oral mucosa: trophyc ulcers with prolonged course and retarded regeneration. One can see legs, arms and other body parts gangrene.
Itsenko-Kushing’s disease. Changings similar to the ones at diabetes mellitus are observed in oral cavity: trophyc ulcers on tongue, cheeks mucosa and other mouth parts. Candidosis is often present.
Addison’s disease. Pigmentation both of skin (at places which are undergone to light action) and mucosae (on lips, on tongue and gums limb, cheeks mucosa) as blue or grey-black small spots and strips takes place. Subjective feelings are absent. Reason: melanin significant accumulation on skin and mucosa. Differential diagnosis should be performed with oral mucosa hereditary pigmentation observed in separate nationalities as well as at hard metals intoxications.
Thus, changins in oral cavity is the mostly often observed at diabetes mellitus, dysfunctions of sexual glands, hypophysis, thyroid, parathyroid and suprarenal gland cortex. That is why timed and correct assessment the local symptoms of these diseases by dentist will encourage their early diagnostics and correspondingly earlier, more adequate and as a result – more effective therapy.
1. Study aims:
To know: physiological functions hormonal regulation characteristics; main mechanisms of hormones action to organism cells.
To be able to: analize regulated parameters and make conclusions about endocrine glands functions regulative mechanisms.
2. Pre-auditory self-work materials.
3.1.Basic knowledge, skills, experiences, necessary for study the topic:
|Histology||Endocrine glands histological structure||Recognize endocrine glands preparations|
|Anatomy||Morphology of endocrine glands|
|Biochemistry||Hormones and other biologically-active substances biochemistry and molecular action mechanism||Write some hormones and other biologically-active substances formulas (according to the programme)|
|Internal diseases (therapy)||Morphology, physiology, biochemistry of endocrinal system, hormones biochemical classification||To analize endocrine system changings at diseases, know their prevention and therapy principles|
|Dentistry||Changings in oral cavity and maxillary-facial region as a whole at endocrinological diseases in adult and children.|
Humoral regulation is performed by means of special internal environment chemical regulators – hormones. These are chemical substances producing and releasing by specialized endocrine cells, tissues and organs. Hormones differ from other biologically active substances (metabolites, mediators) by their producing in specialized endocrine cells and because they act to organs located far from them.
One consider that hormonal regulation is realized by endocrine system. This functional unity consists of endocrine organs or glands (for example, thyroid, suprarenal glands et al.); endocrine tissue in organ (endocrinocytes accumulation for example Lanhergans’ insulas in pancreas); organ cells possessing (besides their main function) endocrine function too (atriums myocytes alongside with their contractile function produce and secrete hormones influencing on diuresis).
Hormonal regulation management apparatus. Hormonal regulation has its own management apparatus. One of such management ways is realized by separate structures of CNS directly transmitting nervous impulses to endocrine elements. This is nervous or cerebro-glandular way (brain-gland). Other way is hypophyseal. Third way of some endocrinocytes activity control is local self-regulation (secretion of sugar-regulating hormones by Langerhans’s insulas is regulated by glucose level in blood; of calcitonine – by calcium level).
Hypothalamus is a central structure of nervous system that regulates endocrine apparatus functions. Such hypothalamus function is connected with neuronal groups existance having the ability to synthesize and to secrete special regulative peptides – neurohormones. Simultaneously hypothalamus is both nervous and endocrine structure. Hypothalamic neurones feature to synthesize and to secrete regulatory peptides receives the name neurosecretion. We would like to mention that in fact all neurons possess this quality – they transport proteins, enzymes synthesized in them. Neurosecret is transmitted into brain structures, liquor and hypophysis. One can differentiate 3 groups of hypothalamic neuropeptides:
· visceroreceptive – primarily act to visceral organs (oxytocine, vasopressine);
· neuroreceptive – neuromodulators and mediators possessing expressed effects to nervous system functions (endorphines, enkephalines, neurotensine, angiotensine);
· adenohypophyseal-receptive – realize adenohypophyseal glandulocytes activity.
Lymbic system belongs to endocrine elements activity management common link with hypothalamus.
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