Thursday, 02 May 2024

Biology includes the study of the anatomy and physiology of living things. Anatomy is the study of structure, and physiology is the study of function.

BODY ANATOMY: General | Cells | Tissues and Organs | Organic Systems | External and internal partitions | Anatomy and Diseases | Questions and Answers | Sources/references

Because the structure of living things is complex, anatomy is divided into levels, from the smallest cellular components to the largest organs and their relationships with other organs. Macroanatomy is the study of body organs as seen with the naked eye during examination and dissection. Cellular anatomy (microanatomy) is the study of cells and their components, which requires special instruments, e.g. microscopes, and special methods of observation.


We often think of cells as the smallest units of living things, but cells are also made up of even smaller components, each of which has its own task. Although different human cells vary in size, they are all very small. The egg fertilized by Tilda, the largest of them, is too small to be seen with the naked eye.


Human cells have an envelope that holds their contents together. However, the envelope (membrane) is not just a bag. It has receptors that allow the cell to be recognized by other cells. Receptors also respond to substances produced in the body and to drugs introduced into the body, and selectively allow all these substances to enter and leave the cell. Reactions that take place at receptors often change and regulate cellular functions.

Video content: biology - cell anatomy

There are two main compartments in the cell envelope: the cytoplasm and the nucleus. In the cytoplasm are structures that consume and convert energy and perform cellular functions. In the nucleus are the genetic material of the cell and the structures that control its operation and reproduction.

The body is made up of many different types of cells; each type has its own structure and function. Some, e.g. white blood cells (leukocytes) move freely, unattached to other cells. Others, e.g. muscle cells are firmly connected to each other. Some, e.g. skin cells divide and reproduce quickly, while nerve cells e.g. they don't reproduce at all. The fundamental task of some, especially glandular cells, is the formation of complex substances, e.g. hormones or enzymes. Cells in the breast e.g. they make milk, in the pancreas insulin, in the lung mucosa mucus and v

In the cell

Although there are different types of cells, most have the same components. A cell consists of a nucleus and cytoplasm. It is surrounded by a cell envelope (membrane), which regulates what enters and leaves the cell.

The nucleus controls the production of proteins. It contains chromosomes, which are the genetic material of the cell, and the nucleolus, which forms ribosomes. Cytoplasm consists of a liquid part and organelles, which can be considered as cell organs. The endoplasmic reticulum transports substances throughout the cell. Ribosomes make proteins that are stored by the Golgi apparatus so they can leave the cell. Mitochondria obtain energy for cellular events. Lysosomes contain enzymes; these can break down particles that enter the cell. Some beta blood cells e.g. they are swallowed by bacteria, which are then broken down by enzymes in lysosomes. Centrioles participate in cell division.

your mouth is drooling. The fundamental task of other cells is not related to the formation of substances - muscle and heart cells, for example, they are shrinking. Nerve cells transmit electrical impulses and thus enable communication between the central nervous system (brain and spinal cord) and the rest of the body.

Tissues and organs

Related cells that are united are called tissue. The cells in a tissue are not exactly the same, but they work together to perform a specific function. A tissue sample that a doctor takes for examination under a microscope (biopsy) contains several types of cells, although he may be interested in only one specific type.

Connective tissue is a firm, often fibrous (fibrous) tissue that connects body structures to each other and provides support. It is found in almost all organs and makes up a large part of the skin, tendons and muscles. The characteristics of the binder and the cell types it contains vary depending on it, where it lies in the body.

Video content: organization of living things

Organs perform bodily functions. Each organ is a recognizable formation that performs a specific task - e.g. heart, lungs, liver, eyes or stomach. Organs are made up of several types of tissues and therefore of several types of cells. Heart e.g. it consists of muscle tissue that contracts to pump blood, connective tissue that forms the heart's valves, and special cells that maintain the speed and rhythm of the heartbeat. The eye contains muscle cells that dilate and constrict the pupil, clear cells that form the lens and cornea, cells that secrete fluid in the eye, cells that sense light, and nerve cells that conduct stimuli to the brain. Even a seemingly simple organ like the gallbladder contains different types of cells, e.g. those that form a coating resistant to the irritating action of bile, muscle cells that contract to expel bile, and cells that form the connective outer wall and hold the sac together.

Organic Systems

although each body has its own specific tasks, the bodies also work as part of a group. Such groups are called organic systems. Organ systems are the organizational units by which medicine is studied, by which diseases are generally classified, and by which treatment is planned. This book is also largely broken down by organ systems.

An example of an organ system is the cardiovascular system, which includes, as the name suggests, the heart and blood vessels. Its job is to pump and circulate blood. The digestive system, which extends from the mouth to the buttocks, is the system responsible for eating and digesting food and eliminating waste. The gastrointestinal tract includes not only the stomach and small and large intestines, through which food moves, but also associated organs, e.g. the pancreas, liver and gall bladder, which produce digestive enzymes, remove toxins and store substances needed for digestion. The musculoskeletal (osteomuscular) system includes bones, muscles, ligaments, tendons and joints that support and move the body.

Video content: 11 organ systems in just 3 minutes

Of course, organ systems do not work in isolation. After eating a large meal, the digestive system needs more blood to perform its tasks. Therefore, they attract the help of the cardiovascular system and the nervous system. The vessels in the gastrointestinal tract dilate to allow more blood to flow through them. Nerve impulses flow to the brain and inform it of increased work. The gastrointestinal tract even directly stimulates the heart with nerve impulses and substances they release into the blood. The heart responds by pumping more blood, and the brain responds by reducing the feeling of hunger, increasing the feeling of satiety and making us less attracted to intense physical activity.

Communication between organs and organ systems is essential. Namely, it enables the body to adjust the functioning of each organ in accordance with the needs of the entire body. The heart needs to know when the body is at rest so that it can slow down, just as it needs to know when the body needs more blood to speed up its activity. The kidneys need to know when there is too much fluid in the body to excrete more urine, and when the body is dehydrated to conserve water.

Through such communication, the body maintains internal balance - homeostasis. With homeostasis, the organs work neither too much nor too little, and each organ facilitates the functioning of all the others.

Communication to maintain homeostasis can take place via the nervous system or through chemical stimulation.

id regulates bodily functions, largely controlling the autonomic nervous system. This part of the nervous system works without the individual thinking about it and also without many signs that would indicate its operation. Substances that serve to communicate are called transmitters. Transmitters that are produced in one organ and travel to other organs via the blood are called hormones, and those that transmit messages between parts of the nervous system are called neurotransmitters.

One of the best-known transmitters is the hormone adrenaline. When a person is suddenly stressed or scared, the brain immediately sends a message to the adrenal glands, which quickly release adrenaline. In a few moments, this substance puts the whole body into a state of readiness; this response is sometimes called the fight-or-flight response. The heart beats faster and harder, the pupils dilate to let more light into the eyes, breathing speeds up, and gastrointestinal activity decreases, allowing more blood to go to the muscles. The effect is fast and strong.

Other chemical communications are less dramatic, but no less effective. If, for example, the body dries up (dehydrates) and needs more water, prothe volume of blood circulating in the cardiovascular system decreases. The reduction in its volume is detected by receptors in the neck arteries. They respond by sending nerve impulses to the pituitary gland, a gland on the underside of the brain, which then secretes antidiuretic hormone. Tk hormone tells the kidneys to make less urine and retain more water. At the same time, the brain detects thirst and encourages the person to drink.

There is also a group of organs in the body - the endocrine system - whose basic task is the production and release of hormones that regulate the functioning of other organs. Thyroid gland e.g. it produces the thyroid hormone, which regulates the rate of metabolism (the speed of the body's chemical reactions), the pancreas produces insulin, which controls the use of sugar, and the adrenal gland produces adrenaline, which stimulates many organs to prepare the body for stress.

External and internal partitions

As strange as it may seem, it is true that in the body it is not always easy to define what is outside and what is inside, because the body has several surfaces. The skin, which is actually an organ system, is one of the obvious surfaces and forms a barrier that prevents many harmful substances from entering the body. Although the ear canal is covered by a thin layer of skin, we usually think it is inside the body because it extends deep into the head. They have a long tube that starts at the mouth, winds through the body and ends at the buttock. Is the food partially absorbed as it passes through this tube inside or outside the body? Nutrients and fluids are not really in the body until they are absorbed into the blood.

Video content: skin and its science.

Air passes through the nose and throat into the trachea, and then into the large, branched airways in the lungs. When is this passage no longer outside the body, but inside it? The body cannot use the oxygen in the lungs until it enters the blood. To get there, it has to pass through the thin cell layer that lines the lungs. This layer acts as a barrier for viruses and bacteria, e.g. for tuberculosis bacteria that can enter the lungs through the air. If the germs do not invade cells or enter the bloodstream, they do not cause disease. Because the lungs have many protective mechanisms, e.g. antibodies to fight infections and chilies to remove debris from the respiratory tract, most infectious organisms never cause illness.

Body surfaces not only separate the outside from the inside, but also keep structures and substances in place so they can function properly. Internal organs, e.g. they do not float in the blood: the blood is generally limited in the veins, if it starts to flow from the veins to other parts of the body (bleeding or hemorrhage), it cannot bring oxygen and nutrients to the tissues, and on top of that it can cause great damage. Example: even a very small hemorrhage into the brain destroys the brain tissue, because there is no room for retreat in the limited space of the skull. spreading. On the other hand, the same amount of blood in the abdomen does not destroy the tissue.

Saliva, which is so important in the mouth, can cause serious damage if inhaled into the lungs. Hydrochloric acid, which is produced in the stomach, is rarely harmful in it. But it can burn and damage the esophagus if it runs into it, or damage other organs if it passes through the stomach wall. Stool, the undigested part of food that is normally excreted through the buttocks, can cause a life-threatening infection if it passes through the intestinal wall into the abdominal cavity.

Anatomy and diseases

The human body is incredibly well made. Most organs have ample spare capacity or reserve: even if they are damaged, they can function adequately. More than two-thirds of the liver must be destroyed before serious consequences occur; a person can survive after removal of an entire lung wing if the remaining wing functions normally. Other organs begin to function poorly even if they experience a small injury. If, for example, If a stroke destroys only a small amount of essential brain tissue, it may happen that the patient can no longer speak, move a limb or maintain balance. A heart attack that destroys part of the heart tissue can only slightly impair the heart's pumping ability, but it can cause death.

Diseases affect anatomy, and anatomical changes can cause disease. Abnormal growths, e.g. cancer, can either directly destroy normal tissue or exert pressure that ultimately destroys it. If the blood supply to the tissue is obstructed or interrupted, the tissue dies (this is called an infarction), e.g. in case of heart attack or stroke (cerebral infarction).

Due to the connection between diseases and anatomical changes, methods that allow insight into the body have become the main pillar of disease detection and treatment. The first breakthrough was X-rays, which allowed doctors to examine the inside of the body without surgery

Another big move was computed tomography (often abbreviated CT), which combines the use of X-rays and computers. A computed tomography image is a detailed, two-dimensional representation of the inside of the body. Other modalities that allow imaging of internal structures include ultrasound (uses sound waves), magnetic resonance imaging (MRS; uses the movement of atoms in a magnetic field), and nuclear medicine (radionuclide) imaging (relies on injecting radioactive tracers into the body). These are all non-invasive ways to examine the inside of the body, as opposed to surgery, which is invasive.

Questions and answers

What are the 5 parts of the anatomy?

Five regions of the body: head, neck, trunk, upper limbs and lower limbs. The body is also divided by three imaginary planes known as the sagittal plane, the coronal plane, and the transverse plane. The sagittal plane runs vertically and divides the body into right and left parts[1].

What are the 7 types of anatomy?

There are several branches or types of anatomy, including gross anatomy, microscopic anatomy, human anatomy, phytotomy, zootomy, embryology, and comparative anatomy. Each branch focuses on a specific part of the study of anatomy. Anatomy has a long and rich history that goes back several centuries[2].

Sources and references

Large health manual for home use, Youth Book Publishing

  1. Anatomical Position -
  2. Anatomy | Definitions, Types & Examples -

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