NERVOUS SYSTEM OF ANIMALS, CENTRAL AND PERIPHERAL NERVOUS SYSTEM OF ANIMAL

Nervous system of animals, central and peripheral nervous system of animal

Nervous system of animals, central and peripheral nervous system of animal

Nervous system of animals, central and peripheral nervous system of animal, spinal canal an animal and sympathetic nervous in animal

The nervous system is one of the leading integrating systems, which carry the interaction and integration of all systems within the whole organism, maintain homeostasis. In addition, the nervous system connects the body with his environment, participating in the process of adaptation. The principle of the nervous system is the doctrine of reflex. 

Nervous system of animals

Reflex - is the body's response to irritation, carried out with the participation and control of the central nervous system. The nervous system is the principle of feedback. In the study of the nervous system representation of the reflex arc has changed the concept of the reflex ring, comprising a receptor sensitive neuron, motor neuron, effector and receptor again, but different. Structural and functional unit of the nervous system are nerve cells - neurons with their processes, synapses (the place of transition from one cell to another, where the electrical signal is transformed into chemical and vice versa). Among neurons are three main types: sensory (afferent), false (associative) and motor (efferent). Processes of nerve cells are the basis of the nerves that are also divided into sensory (somatic and visceral) motor (somatic and autonomic) and trophic.

Nervous system of horse 

For topographical principle nervous system is divided into the central nervous system 
(brain and spinal cord) and peripheral nervous system (spinal and cranial nerves with their roots, branches, ganglia and endings). For functional grounds entire nervous system is divided into somatic (innervates musculoskeletal and skin) and autonomic (innervates internal organs and blood vessels, ie smooth muscle tissue).

Central nervous system

brain, Nervous system of animals

The central nervous system is a tubular structure, that contains a cavity that is in the spinal cord called the central spinal canal and the brain - the ventricles. Completed this cavity cerebrospinal fluid. Central Division of the nervous system has three meninges: hard, soft and gossamer, between which are formed podobolochechnye space is also filled with cerebrospinal fluid. Central Division of the nervous system is formed by gray and white brain matter. 

nerve, Nervous system of animals

Grey medulla represented bodies and processes of nerve cells containing nerve centers and is around cavities (only in cerebral hemisphere and cerebellum gray matter at the periphery and is called the cortex). White medulla established branches of nerve cells and represents the pathways of the brain, located at the periphery of the brain (except cerebellum and cortex). The spinal cord (medulla spinalis) located in the spinal canal and close segments by moving away spinal nerves. The spinal cord is divided into the same sections as the spine: cervical, thoracic, lumbar and sacral. Lumbosacral spinal cord with nerves off of it forms a ponytail. Gray matter of the spinal cord forms the horns of different functions: dorsal horn is sensitive ventral - motor, and thoracolumbar spine is lateral horns containing centers of the sympathetic nervous system. White matter of spinal cord forms: dorsal (sensory pathways), ventral (motor pathways) and lateral (mixed).Spinal cord following functions: conductor (includes pathways that connect different parts of the central nervous system), reflex (contains some centers reflexes), sensitive (associated with the perception of pain). Brain (encephalon) is divided into diamond-shaped and large. Rhomboid brain is divided into the medulla (medulla oblongata) and back, which consists of the cerebellum (cerebellum) and bridge (pons).When the cerebellum is the fourth cerebral ventricle.

pons, Nervous system of animals

In the medulla oblongata are centers of cardiovascular activity, respiration, vomiting center, saliva and tearing, motility of the stomach and intestines. Since the cerebellum is associated equilibrium function, motor coordination and muscle tone. The bridge consists mainly of white medulla and contains powerful conducting apparatus of the cerebral cortex to the spinal cord. Large brain (cerebrum) consists of medium, intermediate and final. Midbrain (mesencephalon) consists of chetveroholmyya and legs of the brain, separated cerebral (Sylvian) water supply. This section of the brain ensures the implementation of motor reflexes under the influence of light and sound stimuli, and includes motor center spinal cord (red nucleus). Diencephalon (diencephalon) of visual hills (talamus), hypothalamus and epithalamus, contains the third cerebral ventricle. This section includes the brain pathways all kinds of sensitivity, performs endocrine function (pituitary and pineal gland), provides regulation of autonomic functions, is responsible for emotions (fear, anger, joy, satisfaction, etc.). Endbrain (telencephalon) consists of olfactory brain , striatum and skirt. Olfactory structures are located on the basal surface of the brain and include the primary olfactory centers. Striatum - basal ganglia - are centers of unconditioned reflexes and cloak - higher integration centers and conditioned reflexes (higher nervous activity). Eventually the brain are also lateral ventricles (first and second).

The nerve center

brain, Nervous system of animals

a group of neurons in the central nervous system involved in the regulation of any function. Neurons that form the nerve center may be located in different parts of the central nervous system.The nerve centers are characterized by a number of properties:

1-unilateral conduction (due to the presence of synapses)

2-slow conduction (due to the large number of synapses in the nerve center)

3-summation of excitation, which can be time and space (defined functional features synapses)

Nervous system of animals

4-irradiation of excitation - excitation of one center causes excitation of another

5-result in nerve centers - excitation delay after the cessation of the stimulus as a result of many nerve connections inside the center

6-facilitate - increase the excitability of the nerve center after each vozb? %83 zhdeniya 

7-convergence (convergence - proceeds to motor neuron impulses in several ways)

8-circulation pulses (due to the presence of many nerve connections between neurons in the nerve center)

9inertia - the ability to maintain long traces of excitement

10-plasticity - the ability to rebuild function, dominant - persistent violation of the center, which occupies a dominant position in the nervous system

11-tone - a state of constant minor offense, fatigue (associated with conducting excitation via synapses due to the high level of metabolism)

12-inhibition - the process weakening or cessation of any activity that may be primary (caused inhibitory neurons) and secondary (occurs in the same neurons in which excitation occurs, under certain conditions).

Higher nervous activity

spinal cord, Nervous system of animals

activity of the higher parts of the nervous system, which in mammals are centers inherent in the cloak of the forebrain. Higher nervous activity is manifested in the ability to develop conditioned reflexes that unlike unconditioned reflexes (the result of subcortical brain) is acquired, transitory, individual, do not have permanent reflex arc produced gradually from unconditioned reflexes handed down from generation to generation in aid learning (imitative reflexes).The biological significance of conditioned reflexes is their participation in the process of behavioral adaptation, so if you change conditions in the cerebral cortex arises process of inhibition of conditioned reflexes. Inhibition divided into conventional (occurs in those centers that himself reflex) and unconditional (provided from outside and may be external and transcendent). For a conditioned reflex to compliance with certain conditions: repeated coincidence in time conditional and unconditional stimuli, conditioned stimulus should begin to act for a few seconds before the unconditioned stimulus.As a result, the two centers in the brain there is a temporary connection as unconditioned reflex center in the brain is dominant, he pulls over excitement that occurs in the center of the conditioned reflex.

spinal canal, Nervous system of animals

The ability to develop conditioned reflexes and speed their development formed the basis of the doctrine of types of higher nervous activity, which is characterized by three parameters: the strength of nerve processes (efficiency of brain cells), balance (the ratio between the strength of excitation and inhibition) and mobility (rate of change of excitation and braking).

Established four types of higher nervous activity:

1. Strong, balanced, agile (sanguine).

2. Strong, balanced, inert (phlegmatic).

3. Strong unbalanced (choleric).

4. Weak (melancholic).

The basis of animal behavior are instincts - a system of chain complex unconditioned reflexes that are in the process of life piling weight of conditioned reflexes.The science that studies animal behavior, called ethology.

Peripheral nervous system

The peripheral nervous system consists of permeate dog body nerves that conduct impulses from receptors to the brain and from the brain to your body. In the course of nerve ganglia are located.Nerves are divided on spinal and cranial. Segments by spinal nerves branch off from the spinal cord with which they are associated spines (dorsal - ventral sensitive and - motor). On the dorsal spine is spinal ganglion. On exit from the spinal canal nerve divided into dorsalnuyu and ventral branches. Ventral branches of nerves, except infants, involved in the formation of nerve plexuses (cervical, shoulder - innervates thoracic limb and lumbosacral - innervates abdominal stack, pelvic limb, external genitalia and udder in females).

Central Nervous system of animals

Among the brachial plexus nerves largest reach of radial nerve (n. radialis), which innervates all extensor elbow, carpal and finger joints, elbow (n. ulnaris) and median (n. medianus) nerves that innervate the carpal and fleksorov finger joints. The median nerve reaches third phalanges.

Among the nerves of the lumbosacral plexus is the largest femoral nerve (n. femoralis), which innervates the quadriceps muscle of the thigh and is located in the femoral canal on the medial thigh and sciatic nerve (n. ischia-dicus), which innervates almost all pelvic limb and is divided into the tibial (n. tibialis) and fibula (n. reroneus) nerves.

The cranial nerves are 12 pairs presented and its functionality are divided into three groups:

1. Sensitive - olfactory (I pair associated with the forebrain), optic (II vapor associated with intermediate brain) and preddverno-cochlear (VIII pair associated with the medulla oblongata).

2. Motor - oculomotor (III couple departs from the midbrain, innervates the muscles of the eyeball), block (IV pair departs from the midbrain, innervates the muscles of the eyeball), abducent (VI pair departs from the medulla innervates m 'muscles of the eyeball), optional (XI pair departs from the medulla and spinal cord, innervates the trapezius and brachiocephalic muscle), hypoglossal (XII couple departs from the medulla innervates muscles of speech).

3. Mixed - trigeminal nerve (V pair departs from cerebral bridge provides sensitive innervation of all regions of the head and motor innervation of masticatory muscles), personnel (VII pair departs from the medulla oblongata, provides innervation of facial muscles, taste buds tongue, salivary and lacrimal glands), glossopharyngeal nerve (IX pair departs from the medulla innervates the region of the pharynx and tongue, parotid salivary gland), vagus (X couple departs from the medulla oblongata, belongs to the parasympathetic nervous system).

Autonomic nervous system

autonomic nervous system, Nervous system of animals  

The autonomic nervous system is divided into two divisions: the sympathetic and parasympathetic, which differ from one location centers and ganglia objects innervation and structure of the motor reflex path.

Sympathetic

Sympathetic division innervates vascular smooth muscle. Its centers are located in the lateral horns of the thoracolumbar spinal cord. Ganglia are on the vertebral bodies (paravertebral ganglia form the border sympathetic trunk) or close to them (prevertebralnye ganglia: cranial cervical, semilunar, caudal mesenteric).

Preganglionic (douzlovye) fibers are short, postganglionic (posleuzlovye) long and part of the cranial nerves, spinal nerves or form a special sympathetic nerves.

Parasympathetic

Parasympathetic division innervates smooth muscles of internal organs and glands. Its centers are located in the middle (hence innervated sphincter pupil), medulla (hence innervated lacrimal and salivary glands, organs and glands neck, chest and abdominal cavities) of the brain and in the lumbosacral spinal cord (hence the innervated organs and glands pelvic cavity). Preganglionic fibers are long and most of them are in the vagus nerve (n. vagus), postganglionic fibers are short. Parasympathetic ganglia located in the wall of the internal organs or surrounding organs (extra-and intramural ganglia).

Senses

a set of anatomical structures that convert the energy of external stimulation in nerve impulse and members of the analyzers. Analyzer - highly complex structures of the body, which distinguish peripheral part - receptor leading portion provided by neural pathways and the central part (area of ​​the brain), where the analysis of nerve impulses. Analyzers different number of properties: high sensitivity, specificity and adaptation, which are caused by the properties of sensory nerve endings - receptors. All receptors are divided into eksteroretseptory (irritable environment and transmit impulses to the cerebral cortex), interoreceptors (excited by stimuli internal environment) and proprioceptors (irritable from musculoskeletal).The structure of the sense organs are eksteroretseptory who perceive the action of temperature, pain and mechanical stimuli (body touch), sound waves (organ of hearing), light (eyesight) and chemical stimuli (olfactory organ and the organ of taste).

Ear, Nervous system of animals

Retseptornaya body part represented taste taste buds located in the taste buds of language. Mostly concentrated in kidney valikovidnyh buds (about 200 in each kidney papilla), and horses - in leaf (about 7000 in each kidney). Authority taste best developed in animals with severe chewing surfaces of teeth (the horse, cattle), with age, body taste partially reduced. Different parts of the tongue have affinity to different chemicals.

Olfactory receptor has representation in the olfactory part of the nasal cavity, and pets and in the ventral meatus (Jacobson organ), where the neurosensory epithelium. The degree of development of the olfactory organ pets belong to makrosmatiki. Among pet smell most advanced in predatory and lagomorphs (rabbit).Body contact is represented nerve endings located in the skin and its derivatives. This tactile and pain sensitivity seen the entire surface of the skin, and information on the nature of the items come from endings corolla horn tip toe and myakyshey.Retseptornaya part of the organ of hearing and equilibrium is called ear.

Ear is represented by three parts:

1. The outer ear (catch unit) consists of the auricle with its own muscular and external auditory canal.

2. Middle ear (transmission apparatus) consists of the tympanic cavity (connected to the pharynx by eustachian tube), the eardrum and four auditory ossicles (hammer, anvil, and stapes bones lenticular).

3. Inner ear (takes phone) consists of two mazes - Bone and pereponchatoho, inserted into each other.Bone maze filled perylymfoy and consists of three bone pivkolovyh channel vestibule and cochlea bone.Membranous labyrinth located inside the bone, filled with endolymph and consists of webby pivkolovyh channels, oval and round sacs (located inside the vestibule), membranous cochlea and endolymphatic duct which communicates with podobolochechnye spaces of the brain.

eyeball, Nervous system of animals

Organ of vision (eye) consists of the eyeball, protective devices and oculomotor apparatus. Eyeball has a three-layered structure and contains svetoprelomlyayuschye environment, which include cornea moist chamber (located in the anterior and posterior chambers of the eye), lens and vitreous.The outer shell of the eyeball (sclera) is protective and its front forming a transparent cornea. The middle layer (suck?% B 4istaya shell) takes trophic function and forms the iris, in the center of which is a hole - iris and ciliary body (it is thicker resnychnaya muscle, which links to the suspended lens). The inner layer (retina) takes receptor function and contains in its composition layer of rods (responsible for crepuscular vision) and cones (provide a sense of color). Protective devices formed bone orbit, periorbitoy, bands orbital fat, conjunctivitis, lacrimal apparatus, eyelids (top, bottom, and third) and eyelashes. Protective devices and oculomotor apparatus includes seven muscles (four straight and two oblique and ottyahivatel eyeball).