What is a human being made of?

Question 1: What are humans made of? What are people made of?

Maybe when my friends saw Ah Xuan and I asked such a question, many friends and many, many people would find it funny. Some people said: "Humans are just skin, hair, bones, meat, Made of blood." Is this answer correct? Of course, it is not wrong to consider it from a certain angle. This answer is too general. If I ask again, "What is a donkey made of? If it is made of skin, hair, bones, meat, and blood, it seems that it can be explained." Haha, just a little joke. Structure of the human body: The smallest unit of the human body is DNA - which contains a large amount of genetic genes and all information about personal health and disease. And DNA is the nucleus, so the human body is composed of trillions of cells. And what do cells rely on to survive? Cells rely on nutrients (proteins, vitamins, minerals, water, fats, carbohydrates and other nutrients) to nourish themselves and their offspring. Cells have a certain life span. For example, cells on the surface of human skin are renewed every 7-10 days, that is, they metabolize once. A woman's egg cells are renewed every 28 days, which means they metabolize. To put it more crudely, it is the work of old cells dying and regenerating new cells to replace the old cells. Continue to work to better maintain the body's yin and yang and nutritional balance to achieve a healthy goal.

Imagine our future. The human spiritual world begins to be deciphered - Freud: Consciousness is actually just a small part of the iceberg that emerges from the water - Jung: The subconscious is an almost immortal collective person - The mandala pattern is like the dragon totem , not from the heart but from the rules of the universe - man and nature are essentially isomorphic - the human brain is a fragment of the holographic picture of the universe, and man is also a living fossil of the evolution of the universe for hundreds of millions of years. Since the beginning of this century, With the spread of Freud's psychoanalytic theory, people's spiritual world began to be deciphered.

Question 2: What structural cells are human beings?

Cells are the structural and functional units of the human body. There are approximately 60 trillion cells, composed of more than 100 types of cells. Tissues and Organs. The average diameter of cells is between 10-20 microns. With the exception of mature red blood cells, all cells have a nucleus, which is the center of regulation of cell function. The largest ones are mature egg cells, with a diameter of more than 0.1 mm; the smallest ones are platelets, with a diameter of only about 2 microns. The lifespan of intestinal mucosal cells is 3 days, the lifespan of liver cells is 500 days, and the lifespan of nerve cells in the brain and bone marrow is several decades, which is almost the same as the human lifespan. The lifespan of red blood cells in the blood is 120 days, the lifespan of white blood cells is only 9 days, and the lifespan of platelets is only 4 days. Throughout the human body, 100 million cells die every minute, 30 million of which are blood cells. The most amazing thing is that the nerve impulse transmission speed of the brain's nerve cells exceeds 400 kilometers per hour, which is equivalent to half the speed of a Boeing 777 aircraft.

Organs

There are about 100 organs distributed throughout the human body, including more than 800 types of various tissues. They perform a variety of functions: digestion, detoxification, immunity, regeneration, autoregulation, etc.

Blood

The total blood volume of the human body is about 8% of the body weight. If the blood loss exceeds 20% of the blood volume in the human body at one time, life activities will be blocked. Healthy people can generally recover quickly if they lose no more than 10 hours of blood at a time. A drop of blood circulates in the human body for 22 seconds.

Chemical composition of the human body

Water accounts for 63% of the human body’s weight. An adult weighing 70 kg will only weigh 25.9 kg after dehydration. Among them, carbohydrates are 3 kg, fat is 9.1 kg, protein is 15.4 kg, and mineral salt is 1.4 kg.

Muscles

There are approximately 639 muscles in the human body. It is composed of approximately 6 billion muscle fibers, with the longest muscle fiber reaching 60 cm and the shortest only about 1 mm. Large muscles weigh 2,000 grams, while small muscles weigh only a few grams. The average person's muscles account for 35-40% of their body weight.

The total length of capillaries in muscles can reach 100,000 kilometers, enough to circle the earth twice and a half.

Bones

It is connected to the muscles responsible for body movement. The human skeleton is composed of 206 bones, including 29 skull bones, 51 trunk bones, and 126 limb bones. The human skeleton does not fully develop until around the age of 25.

Skin

The total skin area of ??an adult is approximately 2 square meters. There are about 3 million sweat glands and 1 billion nerve endings hidden under the skin; men have 16 million hair follicles, while women only have 4 million, so men have more hair than women; there are 450 pairs of motor muscle tissue, which requires a lot of movement when walking. It affects about 54 muscles, and a smile also affects about 17 facial muscles.

Brain

The brain is composed of about 14 billion cells and weighs about 1,400 grams. The thickness of the cerebral cortex is about 2-3 mm, and the total area is about 2,200 square centimeters. It is estimated that the brain Between 1,000 and 100,000 cells die every day (the less you use your brain, the more brain cells die). The capacity of a person's brain to store information is equivalent to 10,000 libraries with 10 million volumes. People who are best at using their brains only use 10% of their brain capacity in their lives. The main component of the human brain is water, accounting for 80%. Although it only accounts for 2% of the body weight, its oxygen consumption reaches 25% of the whole body's oxygen consumption, and its blood flow accounts for 15% of the heart's blood output. The blood flowing through the brain in a day is 2000 liters. The energy consumed by the brain is equivalent to approximately 25 watts in terms of electrical power.

Question 3: How is a human being made up? The human body is composed of chemical elements. There are more than 60 elements that make up the human body. Among them, there are 11 essential quantitative elements such as calcium, sodium, potassium, magnesium, carbon, hydrogen, oxygen, sulfur, nitrogen, phosphorus, and chlorine, which are concentrated in the first 20 elements of the periodic table, as well as iron, copper, zinc , manganese, cobalt, vanadium, chromium, molybdenum, selenium, iodine and more than ten kinds of essential trace elements. Among them, the four elements calcium, sodium, potassium and magnesium account for more than 99% of the total metal ions in the human body. Most of them exist in the human body in the form of complexes, transporting various substances necessary for life and regulating human metabolism. When a certain element in the diet is missing or insufficient, it will affect human health!

How did humans originate and evolve?

People all over the world are very interested in their ancestors and often wonder: Where do we come from? Who are our ancestors? Under what circumstances and through what procedures did they slowly derive, differentiate, and spread all over the world? It is generally believed that humans evolved from ancient apes, and humans and apes have a certain close relationship. The first common ancestors of humans and apes are Protothepithecus and Apes who lived in the Fayoum Depression of Egypt 30 to 35 million years ago. Egyptian ape. From this ancestor, the ancestors were divided into two branches: one became apes, and the other developed into humans. As for how members of the "Hominidae" became humans, it is generally believed that a group of ancient apes evolved from Ramapithecus, Australopithecus, Homo erectus, Homo sapiens, etc., and finally evolved into modern humans. The main reason is based on comparing the similarities and differences in physiological and social characteristics between humans and apes.

Through long-term observation and research by biologists and anthropologists, it has been discovered that humans and apes have extremely similar characteristics in terms of appearance, anatomy, physiology, and blood biochemistry. From the appearance, the body of apes is similar to that of humans, except that members of the family Hominidae can stand up straighter, while apes are in a semi-vertical position, and their hind limbs can temporarily stand upright, or walk on two legs; their faces are hairless or less hairy , without a tail; the position and appearance of the facial features are very similar to those of humans; apes have the same 32 teeth as humans, and the structure of the teeth is generally similar to humans; in terms of body structure, apes have roughly the same skeleton as humans type; in terms of basic physiological phenomena, apes and humans are similar in many places, especially the early stage fetuses of apes and human fetuses are very similar; in terms of blood biochemistry, apes and humans also have very striking similarities or similarities. , all have blood types such as A, B, O, AB; the chromosomes of great apes prove that the shape and position of the chromosomes of apes are also similar to those of humans.

Analyze their evolutionary process from the perspective of brain capacity: the brain capacity of the African Australopithecus 3 million years ago was 440 cubic centimeters; the brain capacity of Homo habilis 1 million years ago was 600-650 cubic centimeters; The brain capacity of Homo erectus about 1 million to 1.5 million years ago was 940 cubic centimeters; correspondingly, the "Lantian ape man" in China was about 1 million to 800,000 years ago, and its brain capacity was 780 cubic centimeters; the Hexian ape man in China It lived about 240,000 to 280,000 years ago. Its brain capacity was 1,025 cubic centimeters, which was similar to that of the Peking Man from Zhoukoudian.

Of course, great apes have many essential differences from humans in terms of physiological structure, language and sociality. For example, humans can make and use tools, they are better able to adapt to the environment, and they have memory and curiosity. People can reason about their own behavior rationally and predictably, they can think abstractly, they have self-awareness and imagination, they have fantasies, etc. In short, they are human beings in terms of engaging in social labor, making tools, and actively transforming nature. Unique. The human brain structure has higher-level and more complex evolutionary characteristics. The essential difference between humans and apes is that humans have language. Another important essential difference between humans and apes is human sociality.

The main process of apes evolving into humans is generally divided into the following two major steps: The first step, the transition from apes to humans, has gone through two stages: Ramapithecus and Australopithecus. In the second step, human beings developed to the primitive commune period and became fully human, going through four stages: early Homo erectus, late Homo sapiens, early Homo sapiens and late Homo sapiens. It is generally believed that labor played a decisive role in the transformation of apes into humans. There are still many debates in the academic community about the origin and evolution of humans.

In addition, there are different opinions on how modern humans originated.

The origin of modern humans refers to the races of people who now live in different parts of the world - yellow people, white people, black people and brown people. There are two theories about how they originated. One is called the "single region origin theory", which holds that modern humans are early Homo sapiens from a certain region who "invaded" all over the world...gt;gt;

Question 4: What is the human head? The brain is the tissue containing the most lipids in the body (except adipose tissue), and the lipids in brain tissue are almost all lipids. 1/2 of the dry brain weight is lipids

Water accounts for 70~80

The rest, such as gray matter, lipids and cholesterol account for about 12

White matter Lipids and cholesterol account for about 28% of it.

Question 5: What are the human fingers that make up the thumb, index finger, middle finger, ring finger, and little finger?

Question 6: What is human skin? The skin is composed of epidermis, dermis and subcutaneous tissue, and contains accessory organs (sweat glands, sebaceous glands, nails, toenails) as well as blood vessels, lymphatic vessels, nerves and muscles.

Question 7: What are humans made of? What are people made of?

Maybe when my friends saw Ah Xuan and I asked such a question, many friends and many, many people would find it funny. Some people said: "Humans are just skin, hair, bones, meat, Made of blood." Is this answer correct? Of course, it is not wrong to consider it from a certain angle. This answer is too general. If I ask again, "What is a donkey made of? If it is made of skin, hair, bones, meat, and blood, it seems that it can be explained." Haha, just a little joke. Structure of the human body: The smallest unit of the human body is DNA - which contains a large amount of genetic genes and all information about personal health and disease. And DNA is the nucleus, so the human body is composed of trillions of cells. And what do cells rely on to survive? Cells rely on nutrients (proteins, vitamins, minerals, water, fats, carbohydrates and other nutrients) to nourish themselves and their offspring. Cells have a certain life span. For example, cells on the surface of human skin are renewed every 7-10 days, that is, they metabolize once. A woman's egg cells are renewed every 28 days, which means they metabolize.

To put it more crudely, it is the work of old cells dying and regenerating new cells to replace the old cells. Continue to work to better maintain the body's yin and yang and nutritional balance to achieve a healthy goal.

Imagine our future. The human spiritual world begins to be deciphered - Freud: Consciousness is actually just a small part of the iceberg that emerges from the water - Jung: The subconscious is an almost immortal collective person - The mandala pattern is like the dragon totem , not from the heart but from the rules of the universe - man and nature are essentially isomorphic - the human brain is a fragment of the holographic picture of the universe, and man is also a living fossil of the evolution of the universe for hundreds of millions of years. Since the beginning of this century, With the spread of Freud's psychoanalytic theory, people's spiritual world began to be deciphered.

Question 8: What elements are humans made of? The human body is composed of more than 80 elements. According to their different contents in the body, they can be divided into two categories: macroelements and trace elements. Those accounting for one ten thousandth of the total weight of the human body are divided into macro (constant) elements and There are two major categories of trace elements. Elements that account for more than one ten thousandth of the total weight of the human body are called macro (constant) elements, such as oxygen, carbon, calcium, hydrogen, phosphorus, and magnesium. There are 11 kinds of trace elements. Elements weighing less than one ten thousandth. Trace elements that are indispensable for maintaining normal life activities of the human body are called essential trace elements. The indispensability mentioned here means that when it is missing, it will cause abnormal physiological functions and structures of the human body, leading to the occurrence of diseases.

There are ***11 kinds of constant elements. Their names and contents are as follows.

Name content/ Name content/ Name content/

Oxygen 65.00 Calcium 2.00 Sodium 0.15

Carbon 18.00 Phosphorus 1.00 Chlorine 0.15

Hydrogen 10.00 Sulfur 0.25 Magnesium 0.05

Nitrogen 3.00 Potassium 0.35

In addition, there are more than 40 elements that make up the chicken body, and their total amount is less than 0.05 of the human body mass. Therefore, these elements are called trace elements in the human body.

Listed below are the main functions of some biological elements in the human body.

Element name main function

Main components of carbon organic compounds

Main components of hydrogen water and organic compounds

Oxygen water And the main components of organic compounds

Nitrogen The components of organic compounds

Fluorine An element necessary for the growth of human bones

Chlorine Extracellular anion (Cl- ), maintain body fluid balance

Composition of iodothyronine

Composition of sulfur protein

Selenium is an element related to liver function and muscle metabolism

Phosphorus is contained in ATP, etc., and is an essential element for biosynthesis and energy metabolism

An essential element for the initial stages of silicon skeleton and cartilage formation

Potassium cation in cells (K ), maintains body fluid balance

Sodium, an extracellular cation (Na), maintains body fluid balance

Calcium is the main component of bones and teeth, and is an essential element for neurotransmission and muscle contraction

p>

Activation of magnesium enzyme, chlorophyll composition, bone composition

Zinc and insulin composition. Active center of many enzymes

Activation of manganese enzyme, essential element for water decomposition in photosynthesis

Iron composes hemoglobin, cytochrome, iron-sulfur protein, etc., and transports oxygen

Components of vitamin B12 necessary for cobalt to form red blood cells

Components of copper-copper protein, absorption and utilization of iron

Molybdenum oxidase, aldehyde oxidase , nitrogenase and other essential elements

Vanadium promotes the mineralization of teeth

Chromium promotes the utilization of glucose, which is related to the mechanism of action of insulin

Various elements in The enrichment situation in human tissue and body fluids is roughly as follows.

In hair: aluminum, arsenic, vanadium;

In brain: sodium, magnesium, potassium;

In pituitary gland: indium, bromine, manganese, chromium ;

In eye fluid: sodium;

In retina: barium;

In dentin and enamel: calcium, magnesium, fluorine;

In tooth tissue: calcium, phosphorus;

In thyroid gland: iodine, indium, bromine;

In heart: calcium, potassium;

In lung: Lithium, sodium;

In pancreas: magnesium;

In kidney: lithium, selenium, calcium, magnesium, potassium, molybdenum, cadmium, mercury;

Digestion In fluid: sodium;

In bones and tendons: lithium, magnesium, potassium;

In muscles: lithium, magnesium, potassium;

In bone tissue: sodium , calcium, potassium, phosphorus;

In blood: iron, sodium, lithium, calcium, potassium;

In liver: lithium, selenium, aluminum, zinc, calcium, magnesium, potassium ,copper.

Question 9: What is the human brain made of? The brain is the tissue containing the most lipids in the body (except adipose tissue), and the lipids in brain tissue are almost all lipids.

1/2 of the dry brain weight is lipids

Water accounts for 70~80

The rest, such as gray matter, lipids and cholesterol account for about 12

White matter Lipids and cholesterol account for about 28% of it

Question 10: What is the basic structure of the human body? (1) Overview of the human body:

1. Four parts: head, neck, trunk, Limbs

2. Three layers: skin, muscles, bones

3. Two cavities: cranial cavity, body cavity (including thorax and abdominal cavity)

4. One tube : Spinal Canal

(2) Basic structure of human body:

1. Cell: basic structure, various shapes

2. Organization: concept, four basic Morphological structural characteristics, distribution, and functions of tissues

3. Organs: concepts, main organs

4. Systems: concepts, eight major systems of the human body (names and functions)

5. Structural level: cell → tissue → organ → system → whole

(3) The human body is a unified whole:

1. From the structural perspective

2. From a functional perspective

Tips on important and difficult points in this chapter

1. The basic structure of the human body. The important thing is to enable students to learn the correct observation methods, cognitive sequence and the ability to use terminology to express correctly.

2. The structural characteristics, distribution and functions of the four basic tissues of the human body. The emphasis is on observation, analysis and comparison, as well as on permeating the adaptive relationship between structure and function.

3. The human body is a unified whole. The focus is on allowing students to experience the coordination relationship between various organ systems of the human body and the regulatory role of the nervous system during activities, and to understand this abstract content in conjunction with actual practice.

4. Through learning activities, students will be aware of the necessity and urgency of learning human physiological and health knowledge, and thus become interested in this course.

Regarding the handling of two teaching difficulties

This chapter has two teaching difficulties: one is the structural characteristics, distribution and function of the organization, and the other is that the human body is a unified whole. The structural characteristics, distribution and functions of tissues are in the same chapter, and theoretical knowledge is relatively concentrated, making it more difficult for students to learn; the human body is a unified whole, which is still relatively abstract and difficult to understand for second grade students. .

(1) Handling of difficulties in "structural characteristics, distribution and functions of organizations".

1. Connect with reality to enhance students' perceptual understanding of the organization and stimulate students' interest in learning.

This is the first time for students to come into contact with the four basic human organizations, so they are a bit unfamiliar. In teaching, paying attention to the connection with reality can enhance students' perceptual understanding of the organization, which not only helps students' memory and understanding, but also stimulates their interest in learning. For example, when talking about epithelial tissue, ask students to recall where the epithelial cells were scraped when doing the experiment of "observing human oral epithelial cells with a microscope"? Use this to help students understand the distribution of epithelial tissue (the inner surface of the walls of various lumens in the body). Through these practical examples, the four basic organizations are brought closer to students' lives, making them no longer unfamiliar and reducing the difficulty of learning.

2. Let students master the structural characteristics of four basic organizations through illustration comparison and experimental observation.

The illustrations are intuitive, vivid and vivid, allowing students to deepen their impressions and improve their memory through comparative observation of the illustrations. For example, if students are asked to compare and observe two illustrations of epithelial tissue and two illustrations of connective tissue, they will find that the structural characteristics of the two are exactly opposite: epithelial tissue has "closely arranged cells and little intercellular substance", while connective tissue has "closely arranged cells and less intercellular matrix". "The intercellular spaces are large and there is more intercellular substance." This way, students can easily remember. Through such comparative observation, students can more clearly remember the structural characteristics of the four basic organizations.

Afterwards, let students distinguish the four basic tissues through microscope observation and further become familiar with the structural characteristics of the four basic tissues.

In order to check students' mastery, the labels on the slide specimens can be removed in advance and numbers can be attached, and students can tell the names of the tissues of each numbered slide specimen through observation.

3. Take care of each other before and after, strengthen the connection between new and old knowledge, and consolidate the knowledge learned.

The content described in this chapter, especially the knowledge about cells, tissues, organs and systems, is different from the morphological structure and physiological functions of each organ system and health care knowledge described in subsequent chapters. degree of contact. Therefore, in future teaching, we should pay attention to the context and strengthen the connection between new and old knowledge to consolidate the knowledge learned. For example, when talking about the structure and function of the skin, it can be linked to the structural characteristics and distribution of epithelial tissue; when talking about the composition of the stratum corneum of the epidermis and the dermis, it can be linked to the protective functions of epithelial tissue and connective tissue.

(2) Dealing with the difficulty of "the human body is a unified whole".

1. Let students understand that the human body is a unified whole from the composition of the human body.

The human body is a unified whole, which is inseparable from its strict and perfect structure. Cells are the basic unit of structure and function of the human body. Some cells and intercellular substance with similar shapes and functions constitute tissues. Different tissues are combined in a certain order to form specific...gt;gt;