Essentials for life
Humans and other animals share many similar traits. All cells in the body are interdependent as we are multicellular organisms. Vital bodily functions occur in various organ systems, contributing to the overall health of the body.
Boundaries
The boundaries of the body are maintained to keep the internal environment distinct from the external environment. All cells in the body are surrounded by selectively permeable membranes. The skin encloses and protects the body as a whole from factors such as dryness, bacteria, heat, sunlight, and chemicals.
Movement
Movement of the body is accomplished through the muscular and skeletal systems. Within the body, the cardiovascular, digestive, and urinary systems also use movement to transport blood, food, and urine. Even cells move, such as when muscle cells move by shortening, known as contractility.
Sensitivity
The ability to feel and respond to environmental stimuli (changes) is known as responsiveness, which is also known as excitability. An example is the way we quickly remove our hands from a hot pan. Nerve cells are highly excitable. They communicate with rapid electrical impulses, and therefore the nervous system is the most sensitive of all the systems in the body. However, all body systems have some degree of excitability.
Digestion
Humans require specific nutrients to stay healthy and to grow and develop normally. Energy is obtained from the breakdown, digestion, absorption and assimilation of food. Digestion breaks down food materials into simple molecules that are more easily absorbed. The absorbed nutrients move through the body's circulation. Nutrient-rich blood is distributed, via the cardiovascular system, throughout the body. Breathing brings in oxygen that works with nutrients to grow and repair parts of the body. The unusable parts of these processes are then excreted as waste.
Metabolism
The body's metabolism controls all of these processes. It includes all chemical reactions within the cells of the body, the breakdown of substances into simpler forms (catabolism), the creation of more complex cellular components from simpler substances (anabolism), and the use of nutrients and oxygen to make molecules. of energy-rich adenosine triphosphate (ATP) (through cellular respiration).
In metabolism, nutrients and oxygen from the digestive and respiratory systems circulate to all cells in the body. Hormones from the glands of the endocrine system have strong regulatory control over metabolism.
Excretion
The process of removing waste from the body is known as excretion. Non-essential substances that are produced during digestion and metabolism must be removed. The digestive system eliminates the components of food that cannot be digested through the feces. The urinary system eliminates urea and other nitrogen-containing metabolic wastes through urine. The blood carries carbon dioxide to the lungs to be exhaled.
Reproduction
Reproduction is a process that occurs on several levels. At the cellular level, reproduction means cell division. The cells divide to produce two identical daughter cells, which the body uses for growth and repair. At the organism level, the human reproductive system unites a sperm with an egg. A fertilized egg is formed, which develops into a baby inside the mother's body. The function of producing offspring is controlled by the hormones of the endocrine system. Reproductive structures differ between the sexes, with the female structures providing a fertilization site for male sperm. The female reproductive structures protect the developing fetus and nurture its growth until birth.
Increase
An increase in the size of an organism or its body parts is called growth. Most often, growth is achieved by an increase in the number of cells. In fact, even when cells don't divide, they can get bigger. True growth occurs when constructive activities occur faster than destructive activities.
Survival
Human beings need various substances to survive: food (nutrients), water, oxygen, pressure and heat in specific amounts and with specific qualities.
nutrients
Food provides nutrients for energy, growth, and regulation of chemical reactions in the body. Some of these chemicals are used as energy sources or provide the raw materials needed to build new living matter; other chemicals help regulate vital chemical reactions. Plant-based foods contain high levels of carbohydrates, vitamins, and minerals. Carbohydrates are the main energy fuel for the body's cells. Certain vitamins and minerals are necessary for chemical reactions within cells and for the transport of oxygen in the blood. Calcium is a mineral that helps make bones strong and is necessary for blood clotting. Foods of animal origin contain high levels of protein and fat. Proteins are the most essential component required to build cellular structures. Fats help in this process and are a great source of energy for the body.
Water
Water is necessary for metabolic processes and makes up most of the actual structure of the body, transporting substances and regulating temperature. It represents 60% to 80% of body weight and is the most abundant chemical in the body. Water allows chemical reactions to occur and is also the fluid base for secretions and excretions. Water is obtained mainly from ingested liquids or food, and is lost in the urine, by evaporation from the lungs and skin, and also in other bodily excretions.
Oxygen
Oxygen is a gas that drives metabolic processes by releasing energy from the food you eat and carrying nutrients to cells throughout your body. This release of energy involves oxidative reactions, for which oxygen is required. Therefore, all nutrients require oxygen in order to be used effectively. Human cells only survive a few minutes without oxygen. Oxygen makes up about 20% of the air we breathe. It is available to the blood and cells of the body by both the respiratory and cardiovascular systems. Adequate amounts of oxygen support life, but even oxygen can be toxic in excessive amounts.
Atmospheric pressure
Proper pressure, specifically atmospheric pressure, is essential for respiration and gas exchange. Blood pressure is a form of hydrostatic pressure that forces blood through the veins and arteries. Atmospheric pressure can be defined as the force that air exerts on the surface of the body. Gas exchange, at higher altitudes, may be insufficient to support cellular metabolism because at these altitudes, the atmospheric pressure is lower and the air is thinner. At sea level, the average atmospheric pressure is 760 mm of mercury (Hg).
Body temperature
Thermal energy is produced from metabolic reactions, which influences their speed. The muscular system generates most of the body heat. Body heat is measured as temperature. A normal body temperature must be maintained if chemical reactions are to sustain life continuously. If the temperature is too high, chemical reactions occur very quickly and the body's proteins change shape and stop working. If the body temperature falls below 98.6°F (37°C), metabolic reactions slow and eventually stop. Death can also occur due to temperature variation.
