Notes, abstracts, papers, exams and problems of Biology

Peripheral Nervous System

Consists of nerves and supports it collects info about the body's external and internal environment.

Central Nervous System

Consists of the brain and spinal cord, processes info, and creates a response.

Cell Body

The largest part of the typical neuron.

Dendrites

Short branched extensions that receive impulses from other neurons and carry them to the cell body.

Axon

Long fiber that carries impulses away from the cell body.

Myelin Sheath

Insulating membrane that surrounds a single, long axon.

Resting Potential

Electrical charge across the cell membrane of a resting neuron.

Action Potential

A nerve impulse that charges more negatively charged to more positively charged.

Threshold

The minimum level of a stimulus that is required to cause... Continue reading "Understanding the Nervous System and Sensory Organs" »

Elastic Fibers

Elastic fibers maintain the position of alveoli and bronchioles. When fibers recoil during exhalation, they reduce the size of alveoli and push air out.

Pneumocyte Type I

Pneumocyte type I cells are squamous epithelial cells that are unusually thin, providing an ideal site for gas diffusion.

Pneumocyte Type II

Pneumocyte type II cells are scattered among the squamous cells and produce surfactant.

Breathing

Deep breathing, also known as diaphragmatic breathing, involves the contraction of the diaphragm to change the volume of the lungs, allowing air to be exhaled passively. Shallow breathing, or costal breathing, occurs when the rib cage alters its shape, changing the thoracic volume.

Dalton's Law

Dalton's Law states that the partial pressure... Continue reading "Elastic Fibers and Gas Exchange in the Respiratory System" »

All organism cells need nutrients to grow and function. Heterotrophic organisms, can`t produce their own nutrients. They obtain them from food. Multicelullar organisms have a lot of organs. Those organs are grouped in different systems that do diverse functions. 5 important systems work together to help our organism being correct: Digestive system, Respiratory system, Circulatory system, Excretory system, Lymphatic system.

DIGESTION.

* Digestive proccess: Like all animals, human beings obtain sugars, fats and proteins from food. This is done thanks to the digestive system. 3 phases are done here: Digestion, Absortion and Expulsion of waste.

The food

Lamarck: The Evolution of Giraffes

1. The ancestors of giraffes had shorter necks and legs than nowadays.
2. As giraffes tried to reach the leaves on the top branches of the trees, their necks and legs grew.
3. Offspring inherited these characteristics.

Darwin: Natural Selection and Giraffe Evolution

1. Giraffes originally had some variation in the length of their necks and legs.
2. Natural selection favored the giraffes with longer necks and legs, leading to increased offspring.
3. As a result, the number of giraffes with long necks and legs increased.

Amniocentesis: Prenatal Genetic Anomaly Detection

Amniocentesis is a technique used in prenatal diagnosis to search for possible genetic anomalies. It involves extracting a sample of amniotic fluid and studying the fetal... Continue reading "Evolution of Giraffes and Human Ancestors: Lamarck vs Darwin" »

Amylase begins the digestive process by breaking down starch when you chew your food, converting it into a smaller carbohydrate. Pepsin helps digest the proteins in food because amylase is at the mouth and the pepsin at the stomach.

Chyle

Is a body fluid in the small intestine. It is turbid and milky due to the presence of emulsified fats. Is formed from the chyme during the digestion of fatty foods.

Intestinal Flora

Is the symbiotic bacteria occurring naturally in the gut.

Defecation

Is the final action of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus.

Mechanical Digestion

This is the enzymatic breakdown of large, complex molecules found in food into smaller, simpler, more... Continue reading "Understanding Digestion, Blood Composition, and the Endocrine System" »

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" »

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" »

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