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

The Endocrine System

The endocrine system is comprised of glands that produce protein substances called hormones. These hormones act as chemical messengers, speeding up or slowing down various activities within the body's cells.

Types of Glands

Exocrine Glands

Exocrine glands release substances through ducts to specific locations. These substances include enzymes, oil, and sweat. Examples include:

• Salivary glands
• Sweat glands
• Oil glands
• Gastric glands
• Intestinal glands

Endocrine Glands

Endocrine glands produce and secrete hormones directly into the bloodstream, acting on target cells throughout the body. Examples include:

• Pituitary gland
• Thyroid gland
• Adrenal glands
• Ovaries
• Testes

Hormones: Action and Functions

Hormones act on specific target cells by binding... Continue reading "The Endocrine System: Glands, Hormones, and Their Vital Functions" »

Gene Pool

The gene pool is the sum of all genetic information carried by all the individuals of a population.

Mutations

Mutations are the ultimate source of all genetic variation, and are the result of random changes in DNA sequences.

Gene Flow

Gene flow is the movement of genes from one population to another. It occurs when individuals migrate from one population to another, thus bringing their genes with them.

Genetic Drift

Genetic drift is a random process where certain alleles are removed from the population by accidental events. It is more likely to affect small populations than larger ones.

Founder Effect

The Founder Effect occurs when a small group of individuals establishes a new population far from existing populations. Because this group is... Continue reading "Evolution and Genetics: A Comprehensive Guide" »

Oral Diseases Associated with HIV

Group 3: Lesions Associated with HIV

• Bacterial infections (e.g., Actinomyces israelii, Escherichia coli pneumonia)
• Cat-scratch disease
• Drug reactions (ulcerative, toxic epidermal necrolysis)
• Fungal infections (e.g., Cryptococcus neoformans, Geotrichum candidum)
• Neurological disturbances (e.g., facial palsy, trigeminal neuralgia)
• Viral infections (e.g., cytomegalovirus)

Kaposi's Sarcoma

Multifocal, vascular neoplasm.

• Decreased immunocompetence activates the latent virus.
• Palate and gingiva are the most common sites.
• Painless red macules progress to nodular lesions.

Differential Diagnosis

• Hemangioma
• Varicosity
• Bacillary angiomatosis
• Pyogenic granuloma

Treatment

• Intralesional injections of vinblastine 0.1 mg/cm² or 0.2 mg/mL saline.

Embryonic Development

HEALTH-Physical mental and social well being

What is a disease?

Change in the body that produces a loss of health. Common terms:

Aetiology Symptom and Sign

Classification of siseases

By the organ or system affected. By persistence: acute or chronic or by transmissibility: infectious or non infectious

-infectious diseases. Caused by pathogens

-Non infectious diseases. Not caused by pathogens

TRANSMISSION OF INFECTIOUS DISEASES

Agent - pathogen that causes a disease

Reservoir. The place where pathogen lives

Vector. The person animal or microorganism that carries and transmits the agent or pathogen

Host. The organism that is infected

Transmission of pathogens

-Direct contact

-Indirect contact

Portals of entry into host

Skin, Respiratory tract, Digestive tract

FUNGI KINGDOM

Cellular Organization:

Unicellular or multicellular, the cells are eukaryotic, they have no tissues.

Size and Shape:

Unicellular fungi, like yeast, are round or oval and microscopic in size.

Nutrition:

Heterotrophic, many are saprophytes, feeding on organic material from animals or plants.

Lifestyle:

They can be free-living symbionts or parasites.

Reproduction:

Unicellular asexual, multicellular asexual, or sexual.

PROTOCTIST KINGDOM PROTOZOA

Cellular Organization:

Unicellular, they have no tissues.

Size and Shape:

Oval, round, oblong, half-moon. All are microscopic.

Nutrition:

Heterotrophic, feeding on bacteria and algae.

Habitat and Lifestyle:

Most are free-living.

Reproduction:

They reproduce asexually by binary fission.

Movement:

They move by using... Continue reading "Characteristics of Fungi, Protozoa, Algae, and Monera Kingdoms" »

Embarrassment:

When something is sudden and unexpected, onlookers are amused. It is a social mistake and makes the person the center of attention. Feeling empathetic for someone else's embarrassment is a display of care. People are often forgiven for their mistakes because they blush, which makes them feel smaller. Embarrassment peaks during teenage years (pregenual ant. cingulate cortex).

Shame:

Shame occurs when a person has failed to live up to expectations or has done something morally wrong. Onlookers are angry, and it often involves poor performance or hurting someone's feelings by failing to meet their expectations.

Guilt:

Guilt is the result of failing to perform one's duty, such as lying, cheating, or stealing (Medial prefrontal, visual... Continue reading "Understanding Emotions and Hormones in Relationships" »

Pulmonary Circuit

The pulmonary circuit involves the right side of the heart, which pumps blood that is partially depleted of oxygen content and contains elevated CO2 as a result of gas exchange in various tissues. This blood is delivered from the right side of the heart into the lungs. In the lungs, oxygen is loaded into the blood, and CO2 is released. This oxygenated blood then travels to the left side of the heart and is pumped to body tissues via the systemic circuit. The systemic circuit pumps an equal amount of blood from both ventricles. Generally, veins pump blood back to the heart, while arteries pump blood away from the heart.

Cardiac Drift

Cardiac drift refers to the increase in heart rate and decrease in stroke volume observed during... Continue reading "Essential Concepts in Cardiovascular Physiology" »

Key Terms in Biology

Water and Macromolecules

• Hydrogen bonds: H2O molecules form these with each other or other polar molecules.
• Carbohydrates: Composed of C, H, and O. Include simple sugars and polysaccharides. Carbohydrate breakdown provides energy.
• Polysaccharides: Carbohydrates made up of 10+ monosaccharides, serving as storage forms of sugars.
• Glycosidic bonds: Bonds formed by a dehydration reaction between two monosaccharides.
• Glycogen/starch: Storage forms of carbohydrates for energy, composed of glucose in alpha configuration (two glucose molecules linked by bonds between C1 and C4).
• Cellulose: Structural component in plants, composed of glucose in beta configuration.
• Chitin: Polysaccharide found in exoskeletons.
• Lipids: Involved in energy storage,

Key Differences Between Bacteria, Archaea, and Eukarya

Cellular Structure

Bacteria: Lack a nuclear membrane, rarely have membrane-bounded organelles, cell walls are constructed of peptidoglycan, possess a single RNA polymerase, and contain histone-like proteins.

Archaea: Lack a nuclear membrane, rarely have membrane-bounded organelles, cell walls are constructed of various materials, possess RNA polymerase II, and contain histones.

Eukarya: Contain a nuclear membrane, possess membrane-bound organelles, some have cell walls, possess RNA polymerase 1, 2, and 3, and contain histones.

Koch's Postulates and Bacterial Shapes

Koch: Discovered Bacillus anthracis (anthrax) and Mycobacterium tuberculosis. His postulates are:

1. Microbes are present in all cases