Notes, summaries, assignments, exams, and problems for Biology

Adaptation to Parasitism

Normally, endoparasites are animals that have undergone major structural changes regarding their architectural pattern, such as the disappearance of unnecessary structures. Locking mechanisms are another common characteristic in parasitic animals. Reproduction and life cycle are significantly affected in animal parasites. Populations often maintain very low levels, so finding a partner can be a problem. The appearance of hermaphroditism ensures reproduction despite the cost of producing two reproductive systems. The production of a high number of eggs compensates for the low probability of one completing the life cycle. The cyst is one of the more developed structures in these animals. Finally, to complete the life cycle,... Continue reading "Parasitism, Coral Reefs, Oligochaeta, and Biological Concepts" »

The Vital Role of Blood in Circulation

Blood is a red liquid that circulates through the blood vessels. It transports nutrients and oxygen to cells and collects carbon dioxide and other wastes.

Blood Composition: Plasma and Cells

Blood is made up of plasma and blood cells.

Blood Plasma Explained

Blood plasma is a yellowish liquid that carries nutrients, hormones, enzymes, and waste products from cells.

Types of Blood Cells

• Red blood cells (RBCs or erythrocytes): These contain hemoglobin, which binds oxygen in the lungs and transports it through the bloodstream to the capillaries, where it is released to reach all cells.
• White blood cells (leukocytes): These defend us from infectious agents like bacteria, viruses, and various parasites that enter through

Cerebral Palsy (CP): An Overview

The M-Bo makes noise due to: air inflow, low oil, or worn parts.

The M-Bo warming indicates: very high pressure, high speed, or poor refrigeration.

The B does not flow due to: base oil, clogged filter, or pump failure.

• Leaks at the pump or motor worn parts
• Leaks in the body
• Bad tightness

The M-Bo does not revolve due to: little flow, internal leakage, improper loading, or unsuitable engine.

Breaking parts can occur due to: pressure excess, stiffness due to lack of fluid, or abrasives not retained.

If the M rotates slower than the flow that arrives, it may be due to: leaks, low pressure input, or high temperature.

Wear excesses of B and M can be caused by: abrasives, excess or no viscosity, or high pressure.

For the v/v regulatory pressure:

• Regulator does

Anthropometry: Measuring the Human Body

Anthropometry is a branch of anthropology focused on the measurement of different human body parts. It provides crucial data for understanding human variation, growth, and development.

Human Body Types: Sheldon's Classification

William Sheldon classified human body types based on the predominance of three fundamental components, known as somatotypes:

• Endomorph: Characterized by a predominance of curves and significant visceral development.
• Mesomorph: Defined by the dominance of muscle and bone, indicating a robust and athletic build.
• Ectomorph: Marked by weak muscular and visceral development, typically featuring long and slender limbs.

Growth and Development of Body Systems

Nervous System Growth

The nervous system... Continue reading "Anthropometry and Human Development: Body Types and Growth" »

Bacterial Characteristics & Cell Shapes

Bacteria are prokaryotic cellular organisms. Their structure is very simple and lacks a nucleus. Most bacteria, with the exception of mycoplasmas, have a cell wall that is more or less rigid, but with a very diverse structure and chemical composition, different from those of plants. Based on cell shape:

• Cocci are small, spherical cells. They group together in pairs (diplococci), in irregular groups or clusters (staphylococci), in rows (streptococci), and in packets (sarcinae).
• Bacilli are short, cylindrical, rod-shaped cells. They may occur as pairs or chains.
• Vibrio are comma-shaped cells.
• Spirilla are rigid, spiral-shaped cells. Spirochetes are long, thin, spiral-shaped cells, which are more flexible

Mitosis

Interphase: This is the state in which the cell is when it is preparing for division. During this time, the cell duplicates its genetic material, grows, and prepares the structures and proteins needed to carry out mitosis.

Prophase: This is the first phase of mitosis. During this phase, the cell's centrioles duplicate, and each pair moves to opposite poles of the cell. The nuclear membrane disintegrates. Chromosomes condense and become visible as double structures.

Metaphase: This is the second phase of mitosis. During this phase, the chromosomes align along the equatorial plane of the cell. The cytoplasmic spindle appears.

Anaphase: This is the third phase of mitosis. The chromatids separate and are pulled towards the spindle poles by... Continue reading "Cell Division: Mitosis, Meiosis, and Hormonal Regulation" »

Hormone Action

Endocrinology studies the glands of internal secretion, responsible for producing hormones, chemical messengers that act on tissues and organs of our body. The pituitary gland is controlled by hypothalamic releasing factors, the thyroid gland secretes thyroxine, the pancreas secretes insulin, the adrenal glands secrete adrenaline and cortisone, and the gonads secrete sex hormones.

Growth Hormone (GH or STH)

Growth hormone originates in the anterior pituitary gland and is considered essential for normal growth. It is classified as anabolic while under the influence of the diencephalic hormone STH. It is specific to the species, and its rate decreases after the age of 30.

Features:

• Stimulates growth and metabolic functions.
• Stimulates

The Nervous System

The nervous system is responsible for processing information and coordinating responses throughout the body.

Nerve Centers

These centers process the information that reaches the sensory organs and elaborate answers.

The Brain

The brain is located in the head, protected by the skull bones. It has an oval shape. It consists of three main parts: the cerebrum, the cerebellum, and the brainstem.

The Spinal Cord

The spinal cord is a long cord that runs inside the backbone. It is connected directly to the brain.

The Cerebellum

The cerebellum is one of the parts of the encephalon, along with the cerebrum and brainstem. One of its most representative functions is to coordinate voluntary movements of the human body. The cerebellum integrates... Continue reading "Human Body Systems: Nervous, Circulatory, and Cardiac Function" »

Plasma Membrane

Structure

The plasma membrane is a flexible and deformable thin envelope that surrounds all cells.

Function

Its mission is to limit the cellular content, but it allows the passage of substances.

Cell Wall

Structure

The cell wall consists of cellulose fibers (a carbohydrate) that confer high resistance and prevent its distortion. This is why plant cells have fixed and often polyhedral forms. Sometimes, the cell wall is covered with a waxy substance that waterproofs it.

Function

It protects the cell and determines its shape, allowing the exchange of substances through pores.

Cytoplasm

The cytoplasm is the internal environment of the cell, where various organelles are suspended.

1. Hyaloplasm

   Structure

   The hyaloplasm is formed by a viscous fluid