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Human Conception: Fertilization and Early Embryonic Development

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The Process of Fertilization

  1. The female gamete, or egg, is captured by the fimbriae (finger-like extensions) of the fallopian tube. Thanks to the muscular contractions of the tube's walls and the movement of its cilia, the egg is gently propelled towards the uterus.
  2. Sperm that have entered the vagina begin their ascent through the reproductive tract.
  3. The surviving sperm continue their journey to the cervix. This region contains glands that produce a specialized mucus fluid. This discharge facilitates the passage of some sperm while trapping others and removing seminal fluid remnants.
  4. Once through the cervix, sperm penetrate the uterine cavity, traverse it, and begin their ascent into the fallopian tubes.
  5. The meeting of sperm and egg, known as fertilization,
... Continue reading "Human Conception: Fertilization and Early Embryonic Development" »

Genetics, Evolution, and Solar System: A Comprehensive Overview

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Genetics

Core Concepts

Genetics is the study of biology that focuses on genes and biological inheritance related to characteristics.

Chromosomes are components that appear as cylindrical or rod-shaped bodies during cell division: mitosis and meiosis.

Genetic engineering involves manufacturing techniques.

The world lives thanks to bacteria and other antibiotic substances they produce. These products prevent the growth of bacteria and fungi.

Cellular Biology and Cloning

Stem cells and blastocysts are cells in the body with no specialized function. They can multiply while maintaining that state and can be transformed into over 200 cell types in an adult individual. They are fundamental.

Cloning:

  • Therapeutic cloning: Obtaining stem cells to regenerate tissues
... Continue reading "Genetics, Evolution, and Solar System: A Comprehensive Overview" »

Understanding Infectious Diseases, Symptoms, and Treatments

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Infectious Diseases: Stages and Characteristics

Infectious diseases manifest through various symptoms, including fever, malaise, and fatigue. These diseases typically progress through three stages:

  1. Incubation Period: The time between the pathogen's entry and the appearance of the first symptoms. During this period, the pathogen multiplies. The incubation period varies depending on the disease.
  2. Development Period: Characteristic symptoms appear.
  3. Convalescence: The body recovers from the disease.

Medical Terminology and Definitions

Symptoms, Signs, and Treatments

Symptom: A subjective experience reported by a patient, perceived as abnormal and potentially caused by a disease.

Sign: An objective, observable indication of a disease or health impairment.... Continue reading "Understanding Infectious Diseases, Symptoms, and Treatments" »

Photosynthesis: Key Reactions and Processes Explained

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Photosynthesis: Key Reactions and Processes

Oxygen Release in Photosynthesis: Oxygen is released during the light-dependent reactions of photosynthesis, specifically when water molecules are split (photolysis).

Organelles Involved: The organelles represented are the mitochondria and chloroplast. Photosynthesis occurs in the chloroplast, and cellular respiration occurs in the mitochondria.

Oxygen as a Waste Product: Oxygen (O2) is produced as a byproduct during photosynthesis and is consumed during cellular respiration.

Anabolic and Catabolic Processes: Photosynthesis is an anabolic process (building complex molecules), while cellular respiration is a catabolic process (breaking down complex molecules).

Photosystems: Structure and Location

Photosystems... Continue reading "Photosynthesis: Key Reactions and Processes Explained" »

Endocrine System: Maintaining Internal Body Homeostasis

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Endocrine, Exocrine, and Mixed Glands

The endocrine system is composed of glands that secrete hormones. Hormones are chemical messengers that travel through the blood and exert specific actions on certain organs, known as target organs.

  • Endocrine glands discharge hormones directly into the bloodstream.
  • Exocrine glands discharge substances onto the body's surface through excretory ducts.
  • Mixed glands combine the features of both endocrine and exocrine glands.

Endocrine System Functions

Hormones are key regulators of metabolism, reactions, and responses to states of alarm.

Endocrine Gland Characteristics

  • Lack excretory ducts
  • Generally small in size
  • Act in small doses
  • Can be formed as independent bodies, arranged in clusters, or within other organs

Pituitary

... Continue reading "Endocrine System: Maintaining Internal Body Homeostasis" »

Understanding Rocks and Cell Organelles

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Understanding Rock Formation

How Igneous Rocks Form

All igneous rocks are formed by the cooling and solidifying of magma. Magma characteristics include its chemical composition, temperature, and density. Crystallization occurs as magma cools and solidifies. This process is called crystallization because the various materials within the magma form crystals. The location where magma solidifies on the Earth's crust influences the type of rock formed.

Igneous rock types:

  • Extrusive
  • Intrusive
  • Plutonic
  • Filonian

Sedimentary Rock Formation

Sedimentary rocks form through compaction and cementation.

Sedimentary rock types:

  • Detritic
  • Rocks formed from precipitation
  • Organic rocks

The Dynamic Rock Cycle

The rock cycle is the set of processes and transformations continually... Continue reading "Understanding Rocks and Cell Organelles" »

Small and Large Intestine: Digestion and Absorption

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The Small Intestine

The small intestine is about 6 meters long. In the duodenum, two liquids are added to continue digestion: pancreatic juice and bile. Pancreatic juice contains enzymes such as lipases, proteases, and carbohydrase (e.g., amylase).

Enzyme Breakdown

Each enzyme breaks down food in the following way:

  • Protein -> protease -> amino acids
  • Lipid -> lipase -> fatty acids and glycerol
  • Carbohydrate -> carbohydrase -> sugar

Bile's Role in Digestion

Bile is made in the liver, stored in the gallbladder, and delivered to the small intestine via the bile duct. Bile neutralizes the acid which was added to the food in the stomach because it is alkaline. This provides the optimal pH for enzymes in the small intestine to work. Bile... Continue reading "Small and Large Intestine: Digestion and Absorption" »

Human Respiratory and Cellular Respiration: Key Functions

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Homeostasis and the Respiratory System

Homeostasis refers to the actions performed by the body to maintain a stable internal environment. The respiratory system plays a crucial role in this process.

Key Components of the Respiratory System

  • Mucus: Contains water and lysozyme, an enzyme that kills bacteria.
  • Trachea: A tube that carries air into the lungs, branching into bronchi and bronchioles.
  • Diaphragm: A muscle that separates the chest from the abdominal cavity.
  • Ribs: Protect the lungs, which have a spongy structure.

The trachea, bronchi, and bronchioles share similar anatomical characteristics. The trachea is horseshoe-shaped and located behind the liver.

Functions of the Respiratory System

  • Gas exchange: The primary function, involving the intake
... Continue reading "Human Respiratory and Cellular Respiration: Key Functions" »

Arthropod and Chordate Biology: Digestion, Absorption, and Transport

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Arthropod Characteristics

Arthropods exhibit bilateral symmetry and a ventral nervous system. Their heart is positioned dorsally, and they have an open circulatory system. They possess an external chitinous exoskeleton, which they shed and replace with a new one during growth, a process called molting. The sensory organs of arthropods are highly developed, primarily located in the head and legs.

Chordate Features

  • The alimentary canal includes glands that aid digestion, such as salivary glands, the pancreas, and the liver.
  • The cerebrospinal nervous system consists of a thick dorsal nerve cord, forming the brain and spinal cord, with nerves branching out.
  • Most chordates have separate sexes. Development typically occurs in eggs, although mammals and
... Continue reading "Arthropod and Chordate Biology: Digestion, Absorption, and Transport" »

Levels of Organization in Living Beings

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Levels of organization refer to the different degrees of complexity in organized matter.

  • Subatomic level: Particles that make up atoms (protons, neutrons, electrons).
  • Atomic level: Formed by atoms; the smallest constituents of matter that retain their properties.
  • Molecular level: Molecules resulting from the binding of different atoms. There are two types:
    • Inorganic: Found in non-living or dead material (water and mineral salts).
    • Organic: Found only in living matter, usually polymers, chains formed by the union of a similar type of monomer molecules.
  • Cellular level: The first level with life.
  • Tissue level: Groups of cells with the same function and similar structure.
  • Organ level: Different tissues are grouped for a particular function.
  • System level:
... Continue reading "Levels of Organization in Living Beings" »