Notes, summaries, assignments, exams, and exercises for Biology for Vocational training

Heart: Function

The heart is responsible for carrying oxygen in the blood and nutrients to all body cells for proper functioning. It is also in charge of collecting and transporting waste material for disposal.

Heart: Structure

The heart is a hollow organ the size of a fist, located in the center of the left chest between the lungs. It consists of a heart wall and four cavities.

Heart Wall

The heart wall has three parts:

• The endocardium is the innermost layer and is in contact with blood.
• The myocardium is the middle layer, composed of cardiac muscle tissue, and it is thick.
• The pericardium is the outer layer containing liquid, and it also absorbs the friction of the heart.

Cardiac Cavities

The heart is divided into two halves, which in turn are divided...

Gross Pathology of Cerebrospinal Fluid

In normal conditions, the cerebrospinal fluid (CSF) is clear and transparent with a pH of 7.4–7.5. Its appearance may change due to various pathological conditions:

• Cloudy or purulent CSF: Indicates an infectious process, such as bacterial meningitis.
• Haematic or yellowish CSF: Suggests hemorrhagic cerebral infarction or trauma. It is important to determine if the presence of blood is due to the procedure or an underlying trauma.

Chemical Composition of CSF

• Glucose Concentration: Normal values range between 50–70 mg/100 mL. Levels decrease in cases of bacterial meningitis or subarachnoid hemorrhage.
• Protein Concentration: Normal values range between 15–40 mg/100 mL. Levels increase in cases of bacterial

The Respiratory System

The respiratory system is responsible for ensuring the supply of oxygen to body cells and removing carbon dioxide. Blood oxygenation is a process that occurs through gas exchange between the blood vessels and the pulmonary alveoli. The respiratory system also prevents the entry of unwanted elements and the development of infections.

Anatomy of the Respiratory System

The respiratory system consists of various organs, which are divided into:

Upper Airways

Located outside the thoracic cavity, including the nose, nares, pharynx, and larynx.

Lower Airways

Located inside the chest cavity, including the trachea, bronchi, bronchioles, alveoli, lungs, and pleura.

Upper Respiratory Tract

1. Nose

   The air enters through the nostrils, right and

Common Foodborne Pathogens and Their Sources

• Clostridium botulinum: Causes botulism, often found in soil or dust.
• Vibrio cholerae: Causes cholera, transmitted by fecal matter.
• Salmonella enterica subsp. enteritidis: Causes salmonellosis.
• Salmonella enterica subsp. Typhi: Causes typhoid fever.
• Shigella: Causes shigellosis.
• Brucella melitensis: Causes brucellosis, transmitted by infected animals.
• Bacillus cereus: Found in soil and dust.
• Campylobacter jejuni: Transmitted by infected animals.
• Clostridium perfringens: Found in soil and dust.
• Escherichia coli: Associated with fecal contamination.
• Listeria monocytogenes: Transmitted by infected animals.
• Yersinia enterocolitica: Transmitted by infected animals.
• Vibrio parahaemolyticus: Transmitted by infected animals.

Male Reproductive System Components

Sperm Production and Testicular Hormones

Spermatogonial: Embryonic cell producing sperm.

Testosterone: A hormone produced by the testis; its function is the development and maintenance of male sexual characteristics.

Hormones Synthesized by the Testis: Testosterone acts on the maturation of testicular germ cells.

Luteinizing Hormone (LH): Stimulates the secretion of testosterone by the Leydig cells.

Follicle-Stimulating Hormone (FSH): Stimulates the Sertoli cells.

Epididymis and Vas Deferens Function

Epididymal Function: Allows the passage of spermatozoa and facilitates their maturation.

Role of the Vas Deferens: Its function is to allow sperm to leave the epididymis and transport them to the ejaculatory duct.

Male

Genetic Disorders

A genetic disorder is a disease caused by an alteration of a gene, called a mutation. These mutations can occur randomly or as a consequence of exposure to some environmental risk factors.

Amniocentesis

Amniocentesis is a test used to determine whether a fetus has a genetic disease.

Environmental Factors

• Exposure to carcinogens: Components of cigarette smoke may induce gene expression, provoking different types of cancer.
• Water and food: In some rural areas, water could be contaminated with pesticides or substances from farms and industries. In developing countries, contaminated water is responsible for many (often fatal) diseases.
• Pollution: Cities with high levels of pollution and areas close to nuclear power plants may increase

Role of Biliary Juice

The biliary juice neutralizes the acidity of the chyme, favoring the action of pancreatic and intestinal enzymes. This action promotes the absorption of fats and fat-soluble vitamins. It emulsifies fats while promoting their digestion by gastric lipase. Furthermore, it stimulates the formation of bile in the liver and removes waste products eliminated by the cells.

Components of Bile Juice

• Biliary Pigments: These excretion products are transported to the liver as a result of red blood cell destruction.
• Bile Salts: These emulsify fats to help digestion and absorption. They are composed of reabsorbable cholesterol, which fully returns to the liver through the portal vein.

Pancreatic Juice and Enzymes

• Sodium Bicarbonate: Neutralizes

1. Digestion: Mechanical and Chemical Processes

Digestion is the set of mechanical and chemical processes involved in food processing. It transforms ingested substances into nutrients—substances contained in food that can be absorbed and utilized by the body.

2. The Digestive System

2.1. The Mouth

• 2.1.1. Lips: Feature the orbicularis oris muscle, a characteristic of mammals that allows infants to suckle without injury.
• 2.1.2. Cheeks: The internal side walls of the mouth.
• 2.1.3. Palate: The roof of the mouth, which separates the oral cavity from the nasal cavity.
• 2.1.4. Teeth: Enable the mechanical processes of chewing, cutting, and grinding food.
• 2.1.5. Tongue: A muscular organ that acts as the primary engine for swallowing and contains gustatory

Neurolinguistics: Language and Brain Function

The study of the relationship between language and the brain is called neurolinguistics. Although this is a relatively recent term, the field of study dates back to the nineteenth century.

Since that time, a number of discoveries have been made about the specific parts in the brain that are related to language functions. We now know that the most important parts are located in areas above the left ear.

Anatomy of Language Processing

In order to describe these areas in greater detail, we need to look more closely at some of the gray matter. If we conceptually dissect the brain—removing hair, scalp, skull, disconnecting the brain stem (which connects the brain to the spinal cord), and cutting the corpus...

Keystone Species

Predators that maintain the balance of other species within the ecosystem.

Trophic Cascade

Ecological phenomenon triggered by the removal or addition of top predators, causing changes in the ecosystem through the food chain.

Green World Hypothesis

Hypothesis stating that predators control the number of herbivores.

Food Chains

Illustrate a single pathway of feeding relationships.

Food Web

Represents the complex relationships between multiple species and their various feeding interactions.

10% Law

As energy transfers through trophic levels, 90% is lost, with only 10% retained. This loss occurs due to metabolic reactions, growth and repair, movement, and heat.

Energy Flow

The movement of energy through the food chain.

Energy Pyramid

Measured