Neck Anatomy

The occiput is the back of the head, the skull base.


The occipital bone is a bone odd and median (single bone in the middle) located to the rear (posterior) and below the skull. The occiput is pierced with a hole (the foramen magnum, also called the foramen magnum) to the passage of the medulla oblongata. The medulla is composed of the upper bulge of the spinal cord containing certain key nerve centers such as regulating breathing. The foramen magnum is bordered on two sides by the hypoglossal nerve and occipital by two ducts. These ducts are shaped cradle and articulate with the first vertebra of the cervical spine, that is to say the part of the spine that supports the skull. This vertebra is named atlas (located above the axis or second cervical vertebra). The articulation at this level allows the inclination of the head.

The occipital bone is almost all of the rear wall and the base of the skull. This bone articulates with the two parietal bones and the two temporal bones through the lambdoid sutures and occipito-mastoid.

The occipital bone is also met the sphenoid bone of the skull base through a narrow blade bone (basilar part of occipital).

Seen from the inside of the skull, the occiput is the walls of the posterior cranial fossa delimiting the cerebellum.
  
The occipito-frontalis muscle is a muscle in two parts (known as belly or middle part), that is to say, the belly and belly frontal occipital. Both bellies are connected by the epicranial aponeurosis. The action of these muscles is as follows: they pull the scalp alternately back and forward.

Neck: Definition

The nape is the back of the neck located below the occiput.


Occipital syndrome (in English occipital syndrome) is characterized by the occurrence of a set of symptoms due to impairment of the brain's occipital lobe (back of the brain). Symptoms include (partial list):

Visual disorders characterized primarily by the appearance of a homonymous hemianopia without involvement of the macula. The hemianopsia is the loss or diminution of vision in one half of the visual field of one eye or two eyes more often. The term homonym means an injury or disorder on the two bodies on the same side, that is located both on the right or left of the median plane (passing through the center of the body). The macula is the depression at the back (posterior) of the retina. Also known as yellow spot, the macula is the area of ​​the retina most sensitive light.
A blind psychic in nature when the lesion is located on the left.
Visual hallucinations.
The occipitalisation of the atlas is the malformation of the area which hinge between the skull base (that is to say the occiput) and the first cervical vertebrae: the atlas. This alteration of the morphology of the skeleton of this part of the neck is characterized by total or partial fusion of the two bones.

Encephalomyelitis is a term derived from the Greek enképhalos: brain and muélos: marrow that means inflammation of the central nervous system (spinal cord). In this condition the patient complains of the following (not exhaustive):

Headache (headache)
Stiff neck
Visual disturbances
Mental and motor disturbance
This neurological disease is sometimes observed after some eruptive fevers. Its evolution is almost always to recovery with or without sequelae.
Some patients encephalomyelitis following an infection by a virus of the Heine-Medin disease.

The hemangiopericytoma is a variety of angioma, occurrence of rare, constituting some of brownish skin tumors appearing mainly on the trunk legs, neck. Sometimes this type of condition also applies when the viscera appearing in the form of visceral tumor.
The development of malignant hemangiopericytoma is sometimes. It is then composed of endothelial cords surrounded by many pericytes that is to say cells with capabilities similar to contraction and smooth muscle cells lining the vessel walls.

The lichen albus von Zumbusch is a variety of lichen porcelain (from Gougerot) based generally on the neck and is characterized by papules that coalesce sometimes white porcelain cupboard rolling contours are angular.

The maduromycose, also called hyphomycétome is a variety of mycetoma, whose type is the disease or Madura foot, may also occur in the neck, and characterized by grains containing large hyphae, fragmented and leading the most often chlamydospores. Slight causes are fungi (maduromycètes), usually Madurella mycetoma, Leptospharia senegalensis and Allescheria boydii.

Münchmeyer's disease is characterized by the production of bone tissue (bone cells) within the same muscle and around him, in the tendons and fascia (membranes covering and protecting muscles). This disease begins early in life through the back muscles and neck and then gradually invades the whole of the musculature.

Acute bulbar paralysis of Leyden, acute bulbar palsy in English, refers to acute inflammation of the basal ganglia located in the medulla (lower polioencéphalite acute) that begins suddenly with headache, pain in the neck, vertigo. This quickly led to a paralysis vélopalatine (soft palate) and sometimes a facial paralysis, dysarthria (slurred speech) and swallowing disorders (difficulty swallowing). Evolution is pejorative, since the death occurs within days. This is preceded by disruption of the cardiac and vascular equipment and sleepiness. This paralysis relates more specifically to individuals intoxicated by alcohol or occurs during the malignant syndrome of certain infectious diseases, the syndrome of Landry or the Heine-Medin disease.

Alopecia areata ophiasique Sabouraud, is a type of alopecia that occurs mainly in children. And that begins with a bald patch at the neck and vertical form. Subsequently plates appear in a horizontal position by adopting the form of wreaths at the lower scalp.

Spiegler's tumor is a tumor of multiple rounded shape, which can reach the size of nine, proliferating at the scalp, sometimes his talents towards the temples, forehead and neck. Analysis of cells constituting the tumor shows the kindness and the fact that the tumor was encapsulated, occasionally lobulated or inground pseudocysts (hence the name cylindroma). It is a hereditary condition which transmission is autosomal dominant.

The rétrocollis is a variety of torticollis in which the head is thrown back because of the contraction of the muscles of the neck.

Posterior cervical sympathetic syndrome is characterized by the onset of headache (headache) occipital (located in back of the skull), dizziness, visual problems and hearing problems. Some patients complain of pain even in the face (facial pain). In some cases the patient hears the cracking in his neck when he moves it. It appears in the rheumatoid cervical spine and probably occur as a result of irritation of the nerve surrounding the vertebral artery (Burtscher-Rochaix syndrome).

Thrombus: Treatment

The fibrinolytic (English fibrinolytic) can dissolve fibrin blood clot. Drugs containing this molecule are particularly used in cases of myocardial infarction. It's all about the streptokinase urokinase, prourokinase and scu-PA.L operation Trendelenburg (in English Trendelenburg's operation) is an opening of the pulmonary artery and remove clots that clog the artery. Without this intervention, pulmonary embolism is likely to be life in danger.Le intravenous filter cellar (in English Endovenous filter) also called Mobin-Uddin filter, filter umbrella filter Greenfield filter umbrella is a device which is introduced into a vena cava catheter. The umbrella filter to stop the migration of clots from the veins of the limbs. This system, usually placed in the inferior vena cava, is to impede the onset or recurrence of pulmonary embolism.

Thrombus: Medical tests

The index of the potential thrombodynamique (IPT) is a number that allows you to get a clear idea, based on the results of thrombo-elastogram, the strength of a blood clot. In some pathologies (structural hypercoagulability), this test is worth practicing. For specialists, the potential thrombodynamique index is calculated by dividing the value of Emx by that of K. The figures are normal between 5 and 10. When they are above 12 is referred to as structural hypercoagulability, when they are less than 5, it is hypocoagulability structurale.Le test Fearnley, called in English Fearnley's test, is the time of lysis is ie destruction of the clot from the blood that was diluted. Fearnley's test is normally more than three hours.The von Kaulla test developed in 1958 (known in English euglobulin lysis test) is synonymous with time measurement of lysis of euglobulins is a method to measure the capacity of destruction of the clot (fibrinolysis) by the blood through the study of fibrinolysis activators, mainly plasminogen. Activators of fibrinolysis are contained in a variety of proteins: the euglobulins. These are precipitated (metropolitan area) by adding an acid (acidification) and then diluted and coagulated. Inhibitors of fibrinolysis, which is part antiplasmin, will float in the liquid obtained. Usually, the clot of euglobulins is destroyed (lysis) after 3 hours, sometimes more. When you get a dissolution (destruction, lysis) faster, it witnessed a plethora of activators and therefore a tendency to fibrinolysis. We talk about: The role is to prevent the normal formation of the clot. Nevertheless, they are the source of certain diseases. These substances consist of antibodies that is to say a variety of proteins belonging to the immune system (defense system of the body). Some of these antibodies are specific to a clotting factor, factor VIII generally. When they are highlighted in the body it means that there is a deficit in the factor responsible. Other anticoagulants cancel the clotting process by intervening at one time or another clotting (phase). This has led to a more global disruption of the body. This is mainly antiprothrombinases. One of the diseases caused by circulating anticoagulant is the lupus erythematosus. In this case it is the lupus anticoagulant or "lupus anticoagulant" by Conley and Hartmann are responsible for this pathology.

Thrombus: Causes

The causes behind the occurrence of thrombosis are relatively numerous. Include (not exhaustive):

Thrombus: Physiology

Specifically, coagulation, causing the formation of a blood clot, can stop the bleeding due to injury among others. This coagulation is first involves a first blood clot color white (platelet thrombus or white) which is caused by platelet aggregation between them: this is the primary hemostasis. The next phase is secondary hemostasis or coagulation itself, corresponding to a sequence of reactions involved in the cascade of proteins that are normally present in blood and specifically in plasma (400 g per liter of blood). These proteins are normally in an inactive state until there is activation that is triggered when certain proteins, particularly factor XII, also known as Hageman factor, comes into contact with the wall of a vessel whose Interior (endothelium) has been damaged or is abnormal. At this point, the contact activation triggers the chain of plasma proteins leading to clot formation. The factors involved in the coagulation cascade are the number of 13. They fall into this complex chain of reactions that results in transforming a soluble protein, fibrinogen, a protein in insoluble fibrin. Fibrin is sort of the skeleton of newly constitué.Le clot clot is the result of the conversion of fibrinogen (which is a variety of proteins) to fibrin (another variety of proteins). Fibrinogen content in blood plasma is produced by the liver and plays an important role in blood clotting. Fibrinogen is also known as coagulation factor I, it is a precursor of fibrin which is part of the cascade described above. Thrombin, another element at play in blood clotting, is another blood protein can activate fibrin. When thrombin-activated fibrinogen, it is converted to fibrin. This will then be polymerized fibrin, that is to say make the joining of many monomers (pieces) and become insoluble as having acquired a stabilization by the intervention of another factor: the factor XIII. From there, a set of proteins is assembled, forming a kind of cap that aims to stop the bleeding: is the filling of the wound by the clot définitif.La clot formation will help to stop relatively rapid bleeding of small vessels when they experience trauma (eg a wound). There are circumstances where there has not been accompanied by trauma but nevertheless hemorrhage: the case of the rules and also in this case, the clot acts as a hemostatic (stop bleeding) . The thrombus appears under pathological conditions, that is to say that it is accidental in a vessel so likely to become blocked. This type of clot occurs in the arteries and veins. When he is in the veins, it is the cause of thrombophlebitis, which in turn could cause a pulmonary embolism (blood clots within the blood circulation of the lungs). When clots form inside the arteries of the general circulation of the body, they are sometimes a source of arterial thrombosis in the coronary (myocardial blood supply vessels, that is to say, the heart muscle), in cerebral arteries (the cause of stroke: stroke) or in the peripheral circulation causing arterial thrombosis, that is to say a decrease in size or even the abolition of passing blood in artères.Physiologiquement is to say, normally in a healthy individual, the clot dissolves after several days, thanks to the intervention of a natural process called fibrinolysis. When necessary, that is to say in the presence of thrombosis, it is possible to accelerate fibrinolysis: it is called thrombolysis. In some cases, it is necessary to intervene surgically to make an unblocking pressure.

Thrombus: Definition

Body obtained after coagulation of blood, half-solid consistency, spongy nature (like a sponge) and consists of a variety of protein: the fibrin in the blood. The clot's role is to retain in its meshes, platelets and red blood cells (RBCs) at the origin of its color very dark red.
The term thrombosis means in turn the formation of a clot (thrombus) in a blood vessel or one of the chambers of the heart in living systems. For some authors this term also refers todisorder that leads to thrombosis.


By extension, the term of thrombosis of choledochal bile Chauffard applies to the formation of large stone that occur within the common bile duct (channel flow in which the bile to the duodenum and confer). The process leading to the formation of this large calculation is as follows: deposition of successive layers of a mixture of cholesterol and bile pigments.
When fresh blood is collected and then brought into contact with air, it quickly turns into a kind of mass, after a few hours, eventually retract and let out (by sweating) a liquid serum which is the liquid part of blood. Indeed, the formed elements (white blood cells, red blood cells and platelets) were retained within the clot and the liquid serum (serum) is the clot on its surface.

The slowing circulation, often the result of a sedentary lifestyle exaggerated. The decay of the vessels and more specifically in the intima, which is to say, the inner wall of the vessels, due to infection or deposits of atherosclerosis (fatty substances). The increase in blood viscosity (decreased hematocrit). In the plasma coagulation Gilbert and Weil (abnormal blood clotting), there is a delay of coagulation, red blood cells have time to settle. The clot then presents a kind of defect, since its upper part, whitish transparent, contains platelets and white blood cells that retract more. It includes a second lower red color more opaque than normal clot. Plasma coagulation for certain severe anemia and is also observed in hemophilia. Syndrome of disseminated intravascular coagulation Hardaway and McKay (in English: Disseminated intravascular coagulation syndrome), also known as DIC, defibrination syndrome, coagulopathy consumption Lasch, is a collection of symptoms characterized by disturbances of blood coagulation due to the disappearance of fibrinogen from the circulating blood. The syndrome of disseminated intravascular coagulation is the result of the sudden onset of activation factors of thrombin leading to fibrin deposition in microvessels leading to their obliteration by thrombosis. They persist longer or shorter. Following this mechanism, the blood becomes incoagulable because it has consumed fibrinogen and other clotting factors (factor V and factor VIII) and platelets. This is the source of bleeding. The hypercoagulability (also called thrombophilia) corresponds to an increase in capacity of the blood to clot. Patients with hypercoagulability the following symptoms: increased speed of blood clotting (known hypercoagulable clotting), the test of tolerance to heparin in vitro and thromboelastography are disrupted, there is also increasing the resistance of the clot (in this case it is a structural hypercoagulability). Blood levels of fibrin and platelets in the blood is higher than normal (see below the lab). Other etiologies (origins) are grouped under the term platelet disorder (qv).

Tetanus vaccination: Medical technology

The dose of tetanus vaccine before the age of 18 months is as follows. It is first necessary to perform subcutaneous or intramuscular injection and a second one month later, a third injection one month later, a recall two years after the third injection and finally, every five years, a new injection, and this into adulthood.
If one wishes to make a preventive vaccination in adults has been inadequately immunized or inadequately immunized should be performed two subcutaneous injections or intramuscular injections at monthly intervals followed by a booster 6 to 12 months after the second injection.
Every 10 years there is a need for subsequent boosters.
If risk of tetanus is also a need for later recall.
For a wound that is suspicious to say tetanigenic likely to become, what to do is this.

    If an individual has been vaccinated and has had all its regular reminders, it is not necessary to conduct supplemental immunization.
    If an individual has been vaccinated and had a call from 5 to 10 years, just before it is then necessary to perform a simple reminder.
    If an individual has been vaccinated once but did not recall its successive it is necessary to make a booster injection associated with immunoglobulin (antibodies) against tetanus (TT) but at a different place the body.
    Of course if a subject has never been vaccinated it is necessary to administer tetanus immunoglobulin and tetanus vaccination started quickly.
Adverse effects of tetanus vaccine are (not exhaustive):

    Nodules (lumps more or less large) where the vaccine is injected
    Hyperthermia (mild fever)
    Sometimes the patient has some awareness (more or less severe reactions) to the vaccine mainly when reminders are too frequent.

Tetanus immunization: Definition

Tetanus vaccine, administered from three months for which there is no indication, cons and should be refrigerated at 2 ° to 8 ° Centigrade consists toxins (poisonous substances from the microbe of tetanus) that have been detoxified is to say, rendered non-hazardous to the body with formaldehyde and then purified. The immunity conferred by the TT appears from the second injection and lasts about 10 years or less depending on the individual and after the first recall.

The indication of the tetanus vaccine is essentially the tetanus prophylaxis (disease prevention).

The tetanus vaccine is mandatory before the age of 18 months, the army and in certain occupations exposed.

It is associated with other pertussis, polio.

It seems that currently only about one third of individuals are properly vaccinated.

Pineal: Physiology

This small endocrine gland (which releases the hormone in the blood) secretes melatonin, a hormone discovered in 1958, which is derived from serotonin (hormone secreted in the brain tissue and having a vasoconstrictor action - closed vessels - and antidiuretic - reducing the manufacturing urine). The properties of melatonin are not known accurately. It seems to have an inhibitory action ("freinatrice") on the secretion of hormones from the pituitary (another gland near the hypothalamus and is considered the conductor of the other glands the body). Melatonin secretion varies with the lighting: it is even stronger than it is low. Sleep may also be modified by the secretion of melatonin. It would also relate to the time difference (effect of "jet lag"). Its action does not stop there: it would also play a role in reproduction, spermatogenesis (sperm production) in humans, in the menstrual cycle in women, and tumor development, adaptation of animals to their environment, the timing of seasonal cycles of reproduction, the timing of a number of diel rhythms (alternating day-night), thermoregulation (regulation of body temperature).
The synthesis of melatonin is controlled by the alternation of day and night.
A study is underway on the possible use of melatonin to fight aging in combination with dehydroepiandrosterone (DHEA).
The pineal gland also acts by inhibiting gonadotropin function, that is to say the action on the sex glands of the hypothalamus, which is an area in the center of the brain and whose action on the regulation of life vegetative (automatic allowing the body to function properly) is paramount. On the other hand, the pineal gland contributes to the synchronization of a number of features rhythmic (circadian or seasonal) and intervenes in the circadian organization (organizational functions of an individual in the twenty-four hours a day).
Regulation of the pineal gland is through the beta-adrenergic receptors, which are small receptors on the glandular cells of the tissue of the epiphysis.

Pineal: Anatomy

The pineal gland is a small gland formation in nature, rounded shape and color grayish, slung beneath the roof of the third ventricle of the brain. It is specifically located to the rear and top of the third cerebral ventricle.
The ventricles are cavities in the brain (nervous system included in the skull).There are:

    The two lateral ventricles of each cerebral hemisphere (half a brain)
    The third ventricle located in the diencephalon (part of the brain between the two hemispheres) and communicating with the lateral ventricles on each side of the foramen of Monro.
    The fourth cavity located in the brainstem (part of the brain between the medulla down, the brain above the cerebellum and back), under the third ventricle between the cerebellum (back) and brainstem (front) . This ventricle communicates with the third ventricle by the aqueduct of Sylvius, and with the surface of the brain by three holes that are the foramen of Magendie and Luschka two holes. Finally, the ventricle communicates with the rest of the spinal cord through a channel from the bottom of the fourth ventricle into the central canal in the center of the spinal cord.
The term epithalamus (from the Greek epi: upon, and thalamos: room) is the dorsal region of the diencephalon which essentially comprises the pineal gland and habenula.The habenula (Latin small belt or band of flesh), also known as stem anterior pineal gland (obsolete term) corresponds to a small projection pair (one on each side of center line) belonging to the epithalamus. It is located in the dorsal and median of the thalamus and joins the epiphysis.
The thalamus is an area of ​​the central nervous system, specifically the brain, consisting of large nuclei of gray matter located on either side of the third ventricle to the front part of the brain. These areas have a role to act as a relay for sensory pathways (nerve carrying sensations). The role of the thalamus is to enable the integration of sensory messages allowed (for) the brain and specifically in the gray matter (cerebral cortex) of it where he carried out the integration of all messages.

Pineal: Definition

The pineal term refers, in general, all things are in the form of an apple.
The pineal gland, obsolete term, is also called epiphysis.
The pineal gland becomes calcified (this deposit of calcium carbonate) during childhood, which does not prevent it from functioning normally. This process makes visible calcifications on radiographs from the age of 20 years.
Syndrome pineal (pineal syndrome in English), also called epiphysis syndrome, is a set of symptoms due to the presence of tumor (cancerous or noncancerous) of the pineal gland (also called pineal body).Patients complain of (partial list):

    Headache (headache)
    Intracranial hypertension (exaggerated blood inside the skull)
    Psychic disturbances
    Ocular
    Paralysis of the pairs of cranial nerves
    Parinaud's syndrome
    Syndrome Argyll-Robertson
    Dysfunction of the reproductive system (macrogénitosomie)
    Subsequently are likely to occur for malfunctions of the cerebellum (cerebellar symptoms) and infundibulo-tubériens (disturbance of the functioning of the hypothalamus and its region).
Apart from the calcifications also describes:

    The cyst of the pineal
    Medulloblastoma of the pineal gland, which is a malignant tumor
    The pinéalocytome also called pinéocytome
    The pinealomas: benign tumor of the pineal gland. For some specialists in neurology, all tumors of the pineal gland are pinealomas. Thus, pinéalocytomes and pineoblastoma or Pineoblastoma, are pinealomas. For others, the only pinealomas are benign tumors of the pineal gland: this is called the pinéalocytomes. The pinealomas occurs mainly in boys with precocious puberty. The fabric forming the brain, most often, not invaded by tumor cells. But in return, it may compress other brain structures such as the aqueduct of Sylvius resulting in the development of hypertension within the skull (intracranial hypertension). This type of tumor can also cause obstruction of the passage between the brain ventricles (cavities containing cerebrospinal fluid within the brain) and more precisely between the third and fourth cerebral ventricle. This phenomenon is known as Parinaud syndrome. It includes a vertical gaze palsy, an abolition of the pupillary reflexes (closing and opening of the pupils when they are subjected to light or dark). When he examined eye of the eye, there is the presence of nystagmus (jerky eye movements due to fast and the eyeball). Some patients on the other hand ataxia (uncoordinated movements) and paralysis that neurologists call paralysis pyramid.
    The term apinéalisme (English apinealism), also known as Marburg's syndrome (described in 1909), is the lack of secretion of the pineal gland. In the past, this syndrome (set of symptoms) was related to the macrogénitosomie secondary to a tumor of the pineal gland.
    The term refers hypopinéalisme inadequate functioning of the pineal gland.

Rétention d'urine : Traitement

In case of acute urinary retention, it is necessary to set up a probe either by natural means (ie the urethra) which corresponds to a survey by urethral bladder evacuator, or by placing a urinary catheter suprapubic (above the pubic bone), that is to say, by direct puncture of the bladder through the wall of the abdomen.

Retention of urine: Medical Examination

Additional tests will help determine the cause through various means:
The detailed clinical neurological examination can reveal diabetes or spinal anesthesia, the etiology (cause) is to be determined.
The urodynamic examination
Ultrasound is sometimes revealed a narrowing of the bladder neck or can move to the cancer of that, a urethral stricture, prostatic adenoma, a fibroid uterus.
Radiology, only in some patients, according to a calculation.

Retention of urine: Medical tests

Through the analysis of urine (urinary cytobacteriological), it is sometimes possible to identify an infectious cause. An antibiotic is necessary to obtain good treatment results by the use of appropriate antibiotics.

Retention of urine : Symptômes

Symptoms of urinary retention are (not exhaustive):
Bladder tension
Pain radiating into the bladder sex
The presence of a distended bladder (bladder filled with voluminous urine)

Retention of urine: Classification

There are two types of urinary retention: 1) Acute: in this case, voiding (that is to say, the emptying of the bladder) is impossible when the persistent urge to urinate. There is the presence of a globe, that is to say, a full bladder. The examination reveals a palpable dome above the pubis. The cause of this phenomenon is an obstacle on the urethra (from the bladder to the outside and to evacuate the urine). In the male, these are diseases of the prostate that are involved most frequently. It can also be a malfunction of the nervous system that manages commands to the evacuation of urine: it is called reflex retention in both sexes. In women, more specifically, it may be a condition requiring corrective sphincter physiotherapy reflexogenic. 2) Incomplete and chronic: in this case, there is urine in the bladder after urination, which leads to the occurrence of a progressive bladder distension alter kidney function. For other types of retention must remember:Bladder retention which corresponds to the accumulation of bile in the gallbladder which the cause is an obstacle located in the routes of excretion (elimination)Dental retention which corresponds to a temporary shutdown or permanent changes within the maxillary (upper or lower jaw) of one or more teeth during their growthChlorine retention is the retention within the body of the ions (atoms that have gained or lost an electron), chlorine (Cl-) due to a decrease in renal excretion (via the kidneys)Retained placenta is the retention in the uterus after delivery, and specifically the issue (the placenta), plots of villi of the placenta may prevent the return to normal of the uterus is to say its physiological involution. This type of infection is sometimes a source of bleeding (bleeding from the uterus outside the rules).

Retention of urine: Definition

Retention is the accumulation of a product that it is liquid, solid or gaseous, in conduit or in a cavity where it is then normally intended to be evacuated. Urine retention is the inability to empty the bladder. The tank containing the lymph is usually referred to as retention.

Specifically, retention of urine (or bladder retention of urine) is defined as an inability to drain a portion or all of the bladder. Individuals affected by the retention of urine are called retentionist.

The substance used are likely to constitute a danger to the body. Indeed they can be sources of toxicity, or volume, usually important, compared to the reserve capacity of the organ (bladder), is a risk to the body accumulates first and the whole organism .