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The frog organogenesis will be studied as an example of the general organogenesis of vertebrates. The following scheme explains in a simplified way how the initial phase of organogenesis occurs in these animals: neurulation. Some of the final destinations of embryonic leaflets in vertebrates in general are: Ectoderma Mesoderm Endoderm Epidermis and skin derivatives, with mucous glands; all structures of the nervous system; Epithelium lining the nasal, anal and oral cavities.

Association in which one individual takes advantage of another's food scraps without harming him. Eg: Shark and Remora, Lion and Hyena, Vulture and Man. Shark and Remora Fish - The shark is recognized as the largest predator of the seas, that is, the individual that normally occupies the apex of the food chain in the thalassocycle.

An extreme case of gene drift is the so-called founder's principle: a new population is “founded” by one or a few individuals, either because the ancestral population has declined drastically, or because a small number of individuals in one population have migrated to another region. , where it gave rise to a new population.

Only around 1860, with the experiments carried out by Louis Pasteur (1822 - 1895), it was definitively proved that microorganisms arise from other pre-existing ones. Pasteur's experiments are described and outlined in the figure below: The absence of microorganisms in the “swan neck” vials kept intact and their presence in the vials whose “neck” had been broken show that the air contains microorganisms and that these, When they come in contact with the nourishing and sterile fluid in the balloon, they develop.

The pulmonary artery departs from the right ventricle and soon forks into the right pulmonary artery and left pulmonary artery, which go to their respective lungs. Once inside the lungs, both divide into as many branches as are the pulmonary lobes; after further subdivision at the level of the pulmonary lobes, these resolve into the pulmonary network.

Red blood cells, white blood cells and platelets are like the parts of a car. Each has a definite function. Red blood cells carry oxygen. Whites fight infections, that is, viruses and bacteria that attack the body and make us sick. And platelets are responsible for stopping bleeding, as when someone cuts their hands - that is, platelets help with blood clotting.

Vitamins are substances used in small doses by cellular metabolism. They almost always act as coenzymes of important enzyme systems of our metabolism. As we do not produce them - the exception is vitamin D, which depends for its synthesis on exposure to the sun, we need to obtain them from the food we eat, often raw, as some are very sensitive to high temperatures, which cause your inactivation.

The thyroid is located in the neck, just below the glottis cartilages, over the initial portion of the trachea. The two main thyroid hormones are thyroxine and triiodothyronine, which respectively contain four and three iodine atoms in their molecules. Both are derived from the amino acid tyrosine.

Huntington's disease is a rare hereditary neurological disorder that affects up to 8 people in each group of 100,000. It is named after the physician George Huntington of Ohio, who described it precisely in 1872. The disease has been widely studied in recent decades. In 1993 the gene that causes the disease was discovered.

Parkinson's disease is a disorder of the central nervous system that primarily affects the motor system. It is one of the most common neurological conditions and its cause remains unknown. Available statistics show that the prevalence of Parkinson's disease in the population is 150 to 200 cases per 100.

Stroke Stroke, popularly known as stroke, can be of two types: ischemic stroke - lack of circulation in an area of ​​the brain caused by obstruction of one or more arteries by atheroma, thrombosis or embolism. It usually occurs in older people with diabetes, high cholesterol, high blood pressure, vascular problems, and smokers.

The propagation velocity of nerve stimuli in the membrane of a neuron ranges from 10cm / s to 1m / s. Such speeds, however, are insufficient to coordinate the actions of large animals. In a giraffe, for example, a pulse traveling at a speed of 1m / s would take between three and four seconds to travel the distance from the hind paw to the brain.

The neuron, the cell common to any nervous system in the Animalia kingdom, resembles, in its function, a conductor of electricity. A typical neuron has three distinct parts: cell body, dendrites, and axon. In the cell body, the largest part of the nerve cell, the nucleus and most cytoplasmic structures are located.

Several terrestrial animals, such as snails, some spiders, scorpions and vertebrates, breathe through the lungs. These are air pockets located inside the body. The oxygen gas in the air that enters the lungs diffuses into the blood or hemolymph, distributing itself into the circulation.

Cross-sectioned, the spinal cord reveals an H-shaped structure that corresponds to the gray matter and where neuron cell bodies are located. Outside this medullary H, is the white matter, composed of myelinated fibers that carry information to the upper parts of the CNS and others that bring the responses to the motor organs.

The cochlea is the part of the inner ear that is responsible for hearing. It is a long conical tube, coiled like a snail shell. Inside the cochlea there is a complex structure called the Corti organ, responsible for capturing the stimuli produced by sound waves. The ear acts as an acoustic shell, which picks up sounds and directs them into the ear canal.

In the human species, various activities of the nervous system are conscious and under the control of the will. Thinking, moving an arm, or changing facial expression are examples of voluntary activities. Many other actions, however, are autonomous or involuntary, that is, they occur independently of our will.

There is a correspondence between Mendel's readings and meiosis. Follow in the figure the process of formation of gametes of a cell of individual dihybrid, relating it to the 2nd Law of Mendel. Note that during meiosis, the homologs align in metaphase and their separation occurs at random, in two equally viable possibilities.

This tissue is the main constituent of the heart wall. Although it is striated, its control is involuntary (it is innervated by the two branches of the autonomic nervous system - the sympathetic and the parasympathetic). The heart muscle fibers are quadrangular and have one or two nuclei located in the center of the fiber.

Independent segregation of two or more gene pairs In addition to studying several phenotypic traits in isolation, Mendel also studied the combined transmission of two or more traits. In one of his experiments, for example, both the color of the seed, which may be yellow or green, and the texture of the seed husk, which may be smooth or rough, were considered simultaneously.