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

Nutritional Requirements and Metabolism

Nutrition Defined

Nutrition: Food intake in relation to the dietary needs of the organism.

Autotrophic Nutrition

Autotrophic: The body's ability to synthesize essential substances for metabolism from inorganic substances. Autotrophs have no need for nourishment from other living beings.

Heterotrophic Processes and Transport

Heterotrophic: Done through movements of molecules and ions via the diffusion process. The cell controls its internal chemical composition to regulate the traffic of substances across the membrane. This occurs through two mechanisms:

• Active Transport: Moves against concentration gradients.
• Passive Transport: Moves toward concentration gradients.

Cell Reproduction and Division Cycles

Cell Reproduction

Pharmacology 2

Dependence: physical response, addiction: behavioral.

Pharmacodynamic principle Placebo effect: patient experiencing relief of symptoms or effect that cannot be attributed to medication. Receptor theory; receptor site, binding site for drug molecule, lock & key. Responses agonist(enhances support encourages response) antagonist( inhibits response drug fits receptor but fails to initiate) neutral(no response). Dose response relationship: inc drug concentration =inc potential receptor site=inc biological effect. Steady state: maintaining blood levels within therapeutic range.

Anti-inflammatories: Steroids: end in -one. NSAIDS: selective(COX2 inhibit celebrex) non selective: upset stomach (salicylates, propionic acid, enolic acid,... Continue reading "Pharmacology 2: Pharmacodynamics, Anti-inflammatories, and Homeostasis" »

The Digestive System

The digestive system transforms food into nutrients that are the right size to reach body cells and be absorbed. To carry out this function, the digestive system consists of a group of organs and structures: the digestive tract and the accessory glands.

The Digestive Tract

The digestive tract, in order from top to bottom, includes:

• Mouth: The entry point of the digestive tract. It contains:
  • Teeth to bite and break food into small pieces.
  • A tongue to mix and swallow food, and enable the sense of taste.
  • Salivary glands.
• Pharynx: A cavity shared by the digestive and respiratory systems. Food passes towards the esophagus. The epiglottis, a small, flexible cartilage, prevents food from reaching the respiratory tract.
• Esophagus: A tube

What is VSG and why is it important in pathogenesis caused by Trypanosoma?

VSG stands for Variant Surface Glycoprotein, and it plays a crucial role in the pathogenesis caused by Trypanosoma, the parasitic protozoa responsible for diseases like African trypanosomiasis.

The importance of VSG lies in its ability to undergo antigenic variation. Trypanosomes have a dense coat of VSG on their cell surface, providing a protective barrier against the host's immune system. The parasite, however, can continually switch between different VSG variants, making it challenging for the host's immune system to mount an effective and lasting defense.

This antigenic variation is a key survival strategy for Trypanosoma during the course of infection. As the immune... Continue reading "VSG and Winterbottom's Sign in Trypanosoma Pathogenesis" »

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

Natural Selection:

Some variations are inherited (passed on from parents) and some are acquired (developed during life). Only inherited variation is passed on to the next generation.
Animals and plants produced by sexual reproduction will show variation from their parents, for example, in the size of the muscles in the legs of lions.
When new organisms are produced, not all of them are likely to survive because of competition for resources such as food, water, and shelter. The same is true for plants (they compete for resources such as nutrients, light, water, and space).
The individuals with the most favorable characteristics are most likely to survive.

The process of natural selection... Continue reading "Understanding Natural Selection and Its Role in Evolution" »

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