Coordination System: Nervous System, Sensors and Hormone Systems in Humans

This time, the Biology material will explain the coordination system and sensory devices. This system will arrange for inter-system work to support each other and be organized. Look carefully at the explanation below.

Chapter List 

Understanding Coordination Systems

All body organ systems can work in harmony due to a coordinating system. This system has the task to receive stimuli, then forward it to the coordination tool, thus determining the response.

The coordination system consists of the nervous system, sensory organs and the hormonal or endocrine system. The work of the coordination system is needed by living things all the time. In some animals, the coordination system is very useful for survival.

Nervous system

The operation of other organs in accordance with their functions on a regular basis due to the operation of the nervous system. The workings of the nerves begin when the stimuli are received by nerve cells. Then, the excitement is sent to the nerve center.

From the central nerve stimulation will be sent to other nerve cells that will respond to the excitement. Furthermore, in general, the nervous system has a function to recognize stimuli that come from outside and from inside the body.

The ability to recognize these stimuli is aided by the senses. The nervous system also has a function to control and regulate the type of activity in response to these stimuli.

Nerve cell . The nervous system in humans is composed of neural networks. The neural network consists of nerve cells or neurons. The structure of one nerve cell can be different from the others, depending on its location and function.

To be able to carry out its functions, nerve cells must have the part that receives and delivers excitatory. Therefore, nerve cells are composed of cell bodies, dendrites, and axons or neurits that have special functions.

The nerve cell body has a function as a cell nucleus, and contains cytoplasm. The function of the nerve cell body is a place to maintain all parts of nerve cells to keep functioning.

Meanwhile, dendrites are cytoplasmic branches in the form of fibers. This dendritic fiber has a function to channel stimulation or stimulus to the cell body.

Then, the axon, is a cytoplasmic outline that is longer in size compared to dendrites. Axon fibers have a function to deliver stimulation from the cell body to other nerve cells.

Inside the axon are fine threads called neurofibrils. This neurofibril has a function to deliver nerve implants. Furthermore, the axon is wrapped in a myelin sheath.

Myelin sheath has a function to protect nerve cells from pressure or injury and accelerate the course of nerve impulses. The structure of the myelin sheath is continuous so that it forms many curves.

The inter-segment indentation is called the axon gap or ranvier node. Then, on the outside there is a membrane covering the cell called a neurolema. The axon ends are sac-shaped containing acetylcholine or excitatory conductors and cholinesterases or neutralizing connections in synapses.

Synapses is a gap that is between two nerve cells meeting. The meeting can occur between dendrites, axons – nerve cell bodies, axons, dendrites, and dendrites – nerve cell bodies.

Nerve cells have the function to carry excitatory from one part of the body to another. These nerve cells can be classified according to their function, consisting of sensory nerve cells, motor nerve cells, and connecting nerve cells or connectors.

Sensory nerve cells carry stimuli from the sensory organs to the center of the nerve system. Meanwhile, the part of the body that receives stimuli is called a receptor. All sense organs can be said to be receptors.

Motor nerve cells carry excitability from the central nervous system to the effector. An effector is a part of the body that carries out commands from the brain as a result of stimulation. Motor nerve cells consist of many dendrites and there is only one axon.

Connecting nerve cells have a function as connecting sensory nerve cells with motor nerve cells. Excitations carried by sensory nerves go to the spinal cord and brain.

Stimulation is received and put together by connecting nerve cells in the spinal cord or in the brain. The connecting nerve cells also deliver stimuli to the motor nerves. Motor nerve cells carry excitatory from the spinal cord or brain to the effector.

The grouping of nerve cells by structure is grouped into unipolar, bipolar, and multipolar nerve cells. Unipolar nerve cells have a body of cells that branch out into axons and dendrites.

Nerve cells are said to be bipolar if there is a dendritic outline and axon outline. While multipolar nerve cells have many dendritic lines and one axon pathway.

Nervous grouping. Nerves in the human body, some are on the axis of the body and some are on the edges of the body. Nerves in the axis of the body form the central nervous system. Meanwhile, those on the edges of the body form the peripheral nervous system.

The central nervous system consists of the brain and spinal cord or medulla spinata. The brain is divided into the cerebrum, cerebellum, and advanced marrow. The cerebrum is composed of two parts, namely the left hemisphere and the right hemisphere.

The left hemisphere, has the function to regulate and control the activities of the right body. While, the right hemisphere has the function to regulate and control the activities of the left body.

Big brain consists of two layers, namely the outer layer and inner layer. The outer layer or cortex has a gray color, there are nerve cell bodies and connecting nerve cells. The surface, cortex folded so that the surface becomes wider.

The inner layer has a white color, inside there are many nerve fibers. The big brain is the center of controlling activities that are realized, namely to think, talk, see, move, remember, and will.

The cerebellum or cerebellum is under the cerebrum. The cerebellum consists of two parts, namely right and left. This cleavage is connected by the varol bridge. The cerebellum has the function to regulate body balance and as a center for coordination of muscle work when moving.

Advanced marrow or medulla oblongata, connecting the cerebellum to the spinal cord. Advanced marrow has functions for heart rate regulating centers, respiratory regulating centers, blood pressure regulating centers, and body temperature regulating centers.

The spinal cord, or medulla spinata, is in the channel formed by the vertebrae. The spinal cord is divided into two layers, the outer layer and the inner layer.

This outer layer has a white color and contains many nerve fibers. Meanwhile, this inner layer has a gray color, containing many cell bodies and connecting nerve cells.

The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system. This peripheral nervous system connects the central nervous system with organs of the body. The peripheral nervous system consists of nerves and ganglia.

The nerve is an extension of the structure consisting of groups of nerve fibers. Furthermore, ganglia are a collection of nerve cell bodies. As mentioned earlier, about the somatic and autonomic nervous system. Both of these nervous systems can be explained as follows.

The somatic nervous system consists of twelve pairs of brain nerves or cranial nerves. In addition, there are also 31 pairs of spinal cord or spinal nerves.

The autonomic nervous system is also called the unconscious nervous system because it works alone without being influenced by consciousness. This autonomic nervous system consists of the sympathetic nervous system and the parasympathetic nervous system. The workings of the two neural structures are antagonistic or antagonistic.

The difference between the sympathetic and parasympathetic nervous system, is as follows.

  • The sympathetic nervous system: accelerates the heart rate, widens the blood vessels of the heart and muscles, widens the bronchi, accelerates the motion of the pertalsis, and accelerates blood pressure.
  • Parasympathetic nervous system: slows the heart rate, narrows heart arteries and muscles, narrows bronchi, slows peristalsis, and slows blood pressure.

Furthermore, based on the way excitatory, motion can be divided into two, namely normal motion and reflex motion. This ordinary motion from the receptor to the sensory nerve then to the brain to the motor nerve and finally to the effector.

While this reflex cracks from receptors to sensory nerves to intermediate neurons or connectors to the motor nerves and finally to the effector.

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Hormone System

Generally, hormones have a function to regulate the body’s balance and the work of body tools. In addition, hormones can affect the means of reproduction, exchange of substances, and behavior.

The hormone that regulates the body’s balance and the work of the organs is actually a substance released by the appendix or endocrine glands. In the human body, there are several endocrine glands.

How this endocrine gland works can not stand alone. between the endocrine glands, one another supports each other. Human endocrine glands include the pituitary gland, the thyroid gland, the thyroid gland, the pancreas gland, the kidney gland, and the genital glands.

The following can be explained about the endocrine glands and their functions.

  • The pituitary gland is the hormone somatrofin. This gland has a function to regulate growth. Where this gland is the main gland or master gland. The pituitary gland consists of three lobes namely the front lobe, middle lobe, and back lobe.
  • Thyroid gland or thyroid hormone thyroxine. This gland has a function to regulate metabolism in the body and affect body and mental development. Lack of this hormone can cause stunt or cretinism, whereas excess of this hormone can cause gigantism.
  • The parathyroid gland is the parathormone hormone. This gland has a function to regulate calcium levels in the body. Lack of this hormone can cause brain seizures.
  • The pancreas gland contains the hormone insulin. This gland has a function to regulate blood sugar levels. Lack of this hormone can cause diabetes mellitus.
  • Gastric and intestinal glands include the hormones gastrin and secretin. This gland has a function to stimulate gastric latex secretion and stimulate bicarbonate secretion. Lack of this hormone can cause the stomach can not digest protein properly, can not break down starch, fat, and protein.
  • Gonadal glands are testosterone, estrogen and progesterone. This testosterone hormone has the function of affecting the development of secondary genitalia in men. Lack of this hormone can cause egg cells in women difficult to mature.

This estrogen hormone has a function for egg maturation and regulation of secondary sex in women. Lack of this hormone causes egg cells in women difficult to mature. This hormone estrogen has a function to affect uterine muscle contractions, milk production. This hormone deficiency causes a lack of milk production.

Furthermore, there are differences in the regulation of bodily activities carried out by nerves and hormones which can be explained as follows.

  • Regulations by nerves: delivery of stimuli quickly, stimuli or impulses are only conveyed to one part of the body, and the response or reaction to stimuli takes place quickly.
  • Regulation by hormones: delivery of stimuli is slow, hormones are expressed in certain organs but affect the whole body, and responses or reactions to hormonal effects generally last for a long time.

Indra system

Sensors as impulse receptors. Based on the type of stimulation received, the sensory devices are divided into chemoreceptors, photoreceptors, mechanoreceptors, and audioreseptors. Chemoreceptors receive stimuli in the form of chemical compounds, for example the tongue and nose.

Photoreceptors receive stimulation in the form of light, for example the eye’s retina. Mechanoreceptors receive stimuli in the form of pressure and temperature, for example the skin. Audioreseptors receive stimuli in the form of sound vibrations, for example the cochlea and ears.

In the human body five kinds of senses are known, namely the tongue, nose, eyes, ears and skin.

The tongue has a function for the taste tool. The rough surface of the tongue is caused by a bulge called the papilla. This papilla has a function for the taste center. The taste papilla on the tongue can be divided into three types, as follows.

Papillary filiform has a thread shape and is spread all over the surface of the tongue. Papilla circumvalata has a shape like the letter v and is in the area near the base of the tongue. Papilla fungiformis has a hammer shape and is on the edge of the tongue.

The nose, inside there is a smell odor. Inside the nose, breathing air is regulated according to its temperature and humidity and its impurities are filtered out by nasal signs. The nose is composed of epithelial cells and nerve odor.

The nose has a function for the sense of smell because it has a receptor or chemoreceptor in the palate – the nasal cavity, which is called the olfactory cells. At the end of the receptor cell are fine hairs or cilia.

In addition, there are also mucous membranes that have a function for moisturizers. The process of stimulating the way in the form of odor is as follows.

The smell in the air into the nasal cavity. Then, it dissolves in the mucous membrane, is received by the smell or olfactory nerves to the brain and is considered as a smell.

The eye has a function for the sense of sight. The parts of the eye consist of the outside and the inside. The outside consists of eyebrows, eyelids, eyelashes, and tear glands.

The inside consists of eyeballs, which are divided into three layers, namely the outer layer, middle layer, and inner layer. The outer layer or sclera consists of the cornea and the lining of the horn.

The middle layer or choroid consists of iris and pupils. Iris or a rainbow membrane that contains pigments that give eye color. In addition, there are pupils that have the function to regulate light entering the eye.

The inner layer consists of the retina and the lens of the eye. The retina has the function of capturing the shadow of objects because there are receptor cells composed of stem cells and cone cells and regulating the objects clearly. The shadow of the object must fall on the yellow spot or fovea centralis.

The lens of the eye is behind the pupil. The lens of the eye has the function of adjusting the shadow of objects so they fall on yellow spots.

The mechanism of seeing can be explained as follows. The light reflected by the object is then captured by the cornea. After from the cornea, then through the pupil, to the lens, retina, nerves, finally in the brain fibers.

Damage and interference with vision, including nearsightedness or myopia, astigmatism, color blindness, cataracts, trachoma, night blindness, glaucoma, and farsightedness or hypermetropy.

Farsightedness or myopia is an ability of the eye that cannot see long distances because shadows fall in front of the retina. This disorder can be helped by using concave or minus lens glasses.

Farsightedness or hypermetrophy , is an eye disorder in which the shadow falls behind the retina so that the eye cannot see at close range. This eye disorder can be helped by convex or positive lens glasses.

Oldsightedness or prebiopi is a combination of nearsightedness and farsightedness due to weakening of the lens of the eye lens. This disorder can be helped by using dual lens glasses or biofocus.

Astigmatism is an eye defect that cannot distinguish vertical lines and horizontal lines simultaneously. This disorder is caused by uneven corneas.

The ear has the function to hear and as a static balance organ. The ear consists of three parts, namely the outer, middle, and inner parts.

The outer ear consists of the auricle, ear canal, oil glands, and eardrum. The middle part consists of the ear cavity and the bones of the ear. This ear cavity has eustachian tubes to maintain air pressure balance.

Hearing bones consist of hammer or maleus, base or incus and stirrups or stapes. The inside of the ear consists of a cavernous window, a round or oval window, three semicircular ducts or ampules that have a function as a means of balancing the body against movement, and the cochlea or cochlea has nerve nerve endings.

As for disorders and abnormalities in the hearing instrument namely conduction deafness and nerve deafness. Conduction deafness is a condition in which the ear cannot hear caused by the presence of dirt that inhibits vibrations to the middle ear.

Meanwhile, nerve deafness is a condition in which the ear cannot hear due to nerve damage.

The skin has a function as a feeler. This is due to the skin having nerve endings as a mechanoreceptor. The names of nerves and stimuli received, i.e.

  • Paccini’s nerve endings receive pressure receptors.
  • The meissner nerve endings and the Merkel’s body receive touch receptors.
  • The ruffini nerve test receives heat receptors
  • The nerve endings of the krausse accept cold receptors
  • The nerve endings without the membrane receive pain or pain receptors.

The skin consists of three layers, namely the epidermis layer , the dermis layer , and the connective tissue layer under the skin . The epidermis layer consists of the epidermis and the malpighi layer.

The dermis layer consists of sweat glands, oil glands, blood vessels, nerve vessels, and hair bladder. Layer of connective tissue under the skin consists of fatty tissue.

Thus the discussion of the coordination system and sensory devices. Hopefully this article is useful for all of you. Have a good study.


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