Human Coordination Systems: Nervous and Endocrine
Coordination Systems
People perform different functions: we move, breathe, digest food, excrete waste substances, and so on. To perform all these functions, we need to interact with the environment, both externally and internally. Using the function of relationship, people, like all other living things, receive information and prepare responses.
To perform the function of relationship, people need to have a coordination system that allows us to detect changes that occur in the environment, analyze
Read MoreHuman Digestive System: From Mouth to Anus
The Human Digestive System
Oral Cavity
Teeth are structures responsible for crushing food. They are harder than bone and contain pieces composed of calcium and fluoride.
- Incisors: Cut food.
- Canines: Tear food.
- Premolars and molars: Grind and blend food.
Premolars have one or two roots and a crown with two protuberances. Molars have four or more roots and four or five protuberances.
Tongue: Participates in the mastication process by moving food around. It also facilitates the passage of the food bolus into
Read MoreCellular Biology: Structure, Function, and Division
In 1838, Mathias Schleiden and Theodor Schwann proposed the following:
- All living things are formed by one or more cells.
- The cell is the simplest and smallest living thing that exists.
- All cells come from pre-existing cells.
- Every single cell carries out its own actions, although there is coordination between cells.
Cell Structure
- Membrane: The border that separates the cell from the environment. Through the membrane, the cell and the external environment exchange products: substances for nutrition enter,
Local Adaptation, Infectious Diseases, Sexual Reproduction, and Extreme Conditions in Biology
Identifying Local Adaptation in Reciprocal Transplant Experiments
In a reciprocal transplant experiment, researchers could place organisms, like deer mice, with dark and light phenotypes in environments with dark soil and light sand. They would then observe the effect of predation on these different phenotypes. This helps to determine if a phenotype is locally adapted to a specific environment.
Why Bats Transmit Infectious Diseases to Humans and Domestic Animals
Bats make up 20% of all mammal species.
Read MoreBody’s Defense Mechanisms: Barriers, Antigens, and Immunity
Body’s Defense Mechanisms
Barriers: Living organisms have developed an intricate network of defenses to prevent the entry of microorganisms. These defenses, or barriers, may be nonspecific, such as the skin, mucous membranes, and specialized cells that perform phagocytosis in macrophages, transported by blood and lymph. Finally, the response may be specific to that microorganism; this response is called immunity. The skin and mucous membranes are the body’s first defensive structures. The skin is
Read MoreImmune System, Childbirth, and Common Infections: A Detailed Look
The Immune System: A Detailed Look
The macrophages alert the immune system when there is a foreign agent in the following way: by exposing fragments of the antigen on the surface of their cells, they alert the immune system.
Differentiating B Lymphocytes and T Lymphocytes
The B lymphocytes circulate in search of specific antigens in the body. When antibodies unite with the antigens to eliminate them, they send signals to the T lymphocytes to stop multiplying, and the immune response against that particular
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