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

Cranial Bones

Sphenoid Bone

The sphenoid bone, shaped like a wedge in the middle of the skull base, presents a body, two lesser wings, two greater wings, and two pterygoid processes. Its upper body contains a cavity that houses the pituitary gland. It participates in the formation of the orbital cavity and contains the sphenoid sinus within its body.

Occipital Bone

It features a large opening, the foramen magnum, which allows for the continuity of the brainstem with the spinal cord. On both sides of the foramen magnum are the occipital condyles, which articulate with the atlas.

Temporal Bone

It has three main parts: the squamous part (forming part of the cranial vault), the petrous part (housing portions of the ear canal, middle ear, inner ear, and... Continue reading "Human Skeletal Anatomy: Skull, Spine, and Thorax Bones" »

Understanding Plant Fundamentals

Plants are multicellular organisms characterized by being anchored to the ground by roots, which absorb water and mineral salts. Chlorophyll, a green pigment, captures light energy. The primary products of photosynthesis are carbohydrates, with oxygen produced as a secondary byproduct.

Plant Transport Systems

Most plants, with the exception of mosses, possess vascular tissues, similar to human blood vessels, through which sap flows. There are two main types of sap:

• Raw sap: A mixture of water and dissolved minerals, it rises from the roots through the xylem.
• Elaborate sap: Containing carbohydrates produced during photosynthesis, it flows through the phloem.

Plant Classification

Plants are broadly categorized into two... Continue reading "Plant Biology: Structure, Function, and Diversity" »

Human Tissue Types

Connective Tissue

Connective tissue consists of specialized cells embedded in an intercellular substance containing fibers like collagen. Key types include:

• Connective Tissue Proper: Binds and supports other tissues and organs, such as tendons and ligaments.
• Adipose Tissue: Composed of adipocytes filled with fat, providing lipid reserves, organ protection, and thermal insulation.
• Cartilage: Made of chondrocytes within a solid intercellular substance, forming structures like the nose, trachea, and ear cartilage.
• Bone Tissue: Composed of osteocytes that develop a strong intercellular substance with mineral salts of calcium and phosphorus, forming bones.
• Blood: Considered by many as a connective tissue with plasma as its intercellular

The Large Intestine

The large intestine is divided into:

• Cecum (Blind): Located after the ileum, contains the appendix.
• Colon: Divided into ascending, transverse, descending, and sigmoid sections.

Functions of the Large Intestine

• Absorbs water, forming feces. Feces consist of undigested food, few nutrients, and bile pigments.
• Synthesizes vitamins created by the intestinal flora. These flora digest substances we cannot and synthesize vitamins for us, a symbiotic relationship.

Rectum and Anal Canal

• Rectum: 15-20 cm in length.
• Anal Canal: 3 cm, opening to the outside through the anus.
• Anus: Contains two sphincters (muscle loops), one involuntary and one voluntary.

The Liver

The liver is located in the upper right quadrant, weighs approximately 1.5 kg, and... Continue reading "Digestive System, Breathing & Oxygen Administration: A Concise Review" »

Physiological Adjustments to Regular Physical Exercise

Cardiovascular System Adaptations

• Increased coronary flow, capillary permeability, and capillary density.

Adaptive Responses of Blood Pressure to Exercise

• Increased blood pressure during exercise and decreased resting blood pressure.

Adaptations in the Respiratory System to Exercise

• Increased frequency and depth of respiration.

Blood Flow Distribution During Exercise

• Increased blood flow in active muscles at the expense of inactive organs.

Cardiac Adaptations: Concentric Hypertrophy

• Corresponds to concentric hypertrophy of the heart, often induced by strength training.

Functions of Respiratory System Adaptations

• To meet O2 demands, eliminate excess CO2, and regulate pH.

Cardiac Output Responses to Exercise

• Trained

Anatomical Foundations: Bones and Joints

Understanding Bone Structure and Function

Osteology: The Study of Bones

Osteology is the branch of anatomy dedicated to the study of bones. Its primary functions include:

• Providing structural support for the body.
• Protecting vital internal organs.
• Facilitating hematopoiesis (the production of blood cells).

Bone Substance and Structure

The compact layer of bone, known as bone substance, is characterized by small cavities containing osteocytes (mature bone cells).

Bone Vasculature and Innervation

Bones are richly supplied with numerous blood vessels and nerves, essential for their nourishment and sensation.

Bone Marrow: Red and Yellow Types

Bone marrow occupies the central portion of bones and can be either red or... Continue reading "Essential Medical and Health Science Definitions" »

Key milestones in genetics include:

• James Watson & Francis Crick (1953): Discovery of the helical structure of DNA.
• Gregor Mendel: Pioneering work in Mendelian genetics.
• Genetic Engineering: Development of techniques to manipulate genes.
• Human Genome Project (HGP): Identifying all the genes of a living being.

Steps in Reading the Genetic Code

1. Separation of the two helical chains.
2. Transcription.
3. Using the Genetic Code.
4. Formation of protein-based amino acids.

Genetically Engineered Foods (GMOs)

Genetically engineered foods are obtained through GMOs and were tagged in 2004, with the following exceptions:

• GM foods with less than 0.9% GMO content.
• Products of second or third generations.
• GM foods that use microorganisms for fermentation.

Genetic Engineering

Genetic... Continue reading "Decoding Genetics: DNA, GMOs, and the Human Genome" »

Understanding Immunity: Types, Disorders, and Hypersensitivity

Types of Immunity

• Natural Passive Immunity

  This process involves the body receiving antibodies without producing its own. Antibodies are transferred through the placenta during embryonic development or via breastfeeding until the infant's immune system fully develops.

• Active Natural Immunity

  Antibodies are formed naturally when the body comes into contact with a pathogen. The individual develops immunity after exposure to the disease.

• Active Artificial Immunity

  The body produces its own antibodies through vaccination. Vaccines contain attenuated or killed pathogenic organisms that stimulate the immune system to create active immunity without causing the disease.

• Passive Artificial Immunity

  This

Effects of Heat on Proteins in Food Processing

Functional Properties of Proteins in Foods

• Mass Hydration: Formation
• Solubility: Emulsification
• Viscosity: Foam formation
• Gelification: Flavoring capture
• Texture: Interaction with other food components

Denaturation of Proteins

Physics

Heating, cooling, mechanical treatment, hydrostatic pressure, radiation.

Chemistry

Acids, bases, metals, organic solvents.

Effects of Protein Denaturation

• Changes in solubility by exposure of hydrophilic or hydrophobic peptide units
• Changes in water absorption capacity
• Loss of biological activity
• Increased risk of chemical attack by exposure of other peptide bonds
• Changes in viscosity of solutions
• Decreased ability of crystallization

Color Changes

Red purple myoglobin converts to metmyoglobin... Continue reading "Protein Changes in Food: Heat, Denaturation, and Functionality" »