Notes, abstracts, papers, exams and problems of Biology

Immunology

By removing serum from pustules of the udder of a cow and injecting it into human skin, an individual suffered from a mild illness but never acquired smallpox. It was the first experiment of active immunization.

1. The Body's Defenses

All organisms have developed mechanisms of defense against the invasion of pathogens. These mechanisms may be nonspecific, preventing entry into the body or destroying them quickly, or very specific, which is known as the immune response.

1.1 Nonspecific Defense Mechanisms

These act against any organism or foreign substance. They are of three types:

a) Natural Barriers: Skin and secretions from the mucosal surfaces.

• Skin is a mechanical barrier because its outermost stratum corneum is fully keratinized.
• It

The Origin of the Moon

• Sister. The Moon formed while the Earth did, but the Moon is 100 million years younger, and their densities are different.
• Adopted. Both formed, but the Moon formed in an area farthest from the Sun and would have been attracted to the Earth. This does not explain the difference in age.
• Daughter. A planet similar to Mars collided with the Earth. Part of the star that crashed formed a debris cloud that orbited around the Earth. The union of these materials created the Moon.

Prebiotic Synthesis

Hypotheses in which life would have originated on Earth as a result of a process:

• Formation of simple organic molecules. Radiation caused molecules to react, forming simple organic molecules.
• Formation of complex organic molecules.

HIV and AIDS: An Introduction

AIDS (Acquired Immunodeficiency Syndrome) is caused by infection with the retrovirus HIV. This virus attacks and destroys T4 lymphocytes and macrophages. Affected individuals have a depressed immune system, which can lead to certain types of cancers.

Development of the Disease

HIV is found in the blood and other bodily fluids of infected persons. Transmission to a healthy person can occur through various routes. These include contaminated blood transfusions and sexual intercourse between an infected and healthy individual.

Once HIV enters the blood of a new host, it joins T cells and penetrates inside. There, a large number of viruses are created, ultimately destroying the infected cell.

AIDS: Treatment and Prevention

There... Continue reading "HIV and AIDS: Understanding the Disease and Prevention" »

Physical Assessment of a Patient with Cancer

Skin

• Inspection: Color, integrity, turgor, humidity, temperature.
• Check for: Injuries (type, size, and location), purpura, petechiae, edema, and appearance of nails.

Head and Neck

• Inspect: Face (asymmetry), eyes, mouth, trachea, maxillary sinuses.
• Palpation: Thyroid.

Thorax

• Inspection: Breathing movements and rate.
• Palpation, percussion, auscultation: Tone, intensity, and duration of breath sounds.

Breasts and Armpits

• Inspection and palpation.

Cardiovascular

• Inspection: Tremors and palpitations in the chest.
• Auscultation, palpation, blood pressure.

Musculoskeletal

• Inspection: Hair distribution, abnormal masses or lesions, asymmetries, nodules.
• Palpation: Painful masses, joint range of motion.

Neurologic

• Presence of

Nutrition: Function and Importance Nutrition includes all processes to get the materials of development and the energy we need to live like .--- La Nutricion: Nutrition is a long process. One step is to take food. Function in the 4 processes involved Nutrition: Circulation - the digestive process, respiration, and excretion Feeding and Nutrients To live, we need the nutrients that food contains. The main groups are carbohydrates, fats, proteins, water, vitamins, and minerals - A diet is complete when it contains all types of nutrients. A balanced diet is when it gives us the necessary amount of each nutrient.

Functions of Muscle Tissue

• Production of body movements
• Stabilization of posture
• Volume regulation of the body
• Movement of chemicals in the body
• Production of heat

Properties of Muscle Tissue

• Electrical excitability
• Contractility
• Extensibility
• Elasticity

Types of Muscle Tissue

There are three types of muscle tissue: striated skeletal, striated cardiac, and smooth.

• Striated skeletal muscle: Called skeletal because the function of these muscles is to move the bones; it often works on a voluntary basis.
• Heart muscle (myocardium): Is located in the heart and is part of its wall. Its movement is involuntary.
• Smooth muscle: Is part of the walls of blood vessels, airways, and some guts. Almost always, this type of muscle movement is involuntary.

Structure of Striated

What is Embryology?

Embryology is the branch of biology that studies the development of an organism from a fertilized egg. It encompasses several key concepts:

• Ontogeny: The transformations that the embryo undergoes during development.
• Phylogeny: The evolutionary history of a species.

Historical Theories of Development

Historically, two main theories attempted to explain embryonic development:

• Preformationism: This theory argued that a miniature version of the organism, called a "homunculus," was present in either the sperm or the egg. Scientists who believed in this were called "animalculists." In 1699, Danlenpatius proposed this theory.
• Epigenesis: This theory proposed that adult body structures were not preformed in the gametes but developed gradually.

Fertilization

Fertilization is the fusion of male and female gametes, initiating the process of reproduction. It's important to note that fertilization of the egg is not immediate upon contact.

Human Fertilization

In humans, fertilization occurs when a sperm and egg unite in the fallopian tubes after sexual intercourse. Humans develop from the union of these two tiny cells. Mature eggs measure approximately 0.135 mm in diameter, while sperm are even smaller. Each ejaculation can contain between 120 and 600 million sperm. The union of these cells has the potential to create a new human being with extraordinary abilities.

Zygote

In biology, a zygote is the cell formed by the union of male and female gametes during sexual reproduction in organisms... Continue reading "Human Reproduction: From Fertilization to Embryonic Development" »

Infectious Diseases

Definition

Temporary or permanent loss of health caused by microorganisms.

Types of Microorganisms

• Bacteria: Unicellular prokaryotic organisms that multiply and can destroy cells and tissues.
• Viruses: Not considered living organisms. They reproduce by entering cells and using their resources, causing damage.
• Protozoa: Single-celled eukaryotes. Some cause disease.
• Fungi: Unicellular and multicellular eukaryotes. Some can cause disease in weakened individuals.
• Parasites: Multicellular organisms that live at the expense of a host, weakening but not killing it.
• Prions: Misfolded proteins that accumulate and cause neuron degeneration.

Non-Infectious Diseases

Nonspecific Defenses

Mechanisms that prevent the entry of microorganisms:

• Skin: Acts

Definition of Infectious Diseases

An infectious disease occurs when a parasite develops and multiplies within a host. The causal agent of transmissible diseases is usually a living organism that moves from one individual to another by contagion. The set of elements that define a communicable disease consists of:

• Reservoir: Where infectious agents are usually found.
• Source of Infection: Animate or inanimate object from which the causative agent originates.
• Mechanism of Transmission: The pathways that allow the causal agent of a transmissible disease to contact the host.
• Host: A person susceptible to contracting a communicable disease upon contact with the source of infection.

Samples arriving at the laboratory for the diagnosis of causative agents... Continue reading "Infectious Diseases: Definition, Transmission, and Diagnosis" »