The cells of epithelial tissues remain attached to each other by specialized structures, generally called cell junctions. Note these junctions in the figure below. Desmosomes One of the most important cell junctions is the desmosomes (from Greek desmos, binding, and soma, body).
While in endocytosis substances enter cells, there is an inverse process: exocytosis. Once endocytized, the material undergoes transformations and the resulting products are absorbed through the membrane of the organite and remaining what remains in the gall bladder from which it will be subsequently exocited.
For a new individual to emerge, gametes merge into pairs, one male and one female, which play different roles in the formation of the offspring. This fusion is fertilization or fertilization. Both carry the same haploid amount of chromosomes, but only female gametes have nutrients that feed the embryo during its development.
Unlike mitosis, where a diploid cell, for example, divides into two diploid cells (equational division), meiosis is a type of cell division in which a diploid cell produces four haploid cells and is therefore a reditional division. . A fact that reinforces the reductive character of meiosis is that, although it comprises two successive stages of cell division, chromosomes duplicate only once during interphase - a period preceding both mitosis and meiosis.
In the phase that the eukaryotic cell is not in division, it is possible to visualize several nucleoli, associated to some specific regions of the chromatin. Each nucleolus is a spongy, non-membranous corpuscle of spongy appearance when viewed under the electron microscope, rich in ribosomal RNA (the abbreviation RNA comes from Ribo Nucleic A cid).
Just as a factory can be multiplied by building multiple branches, so cells divide and produce copies of themselves. There are two types of cell division: mitosis and meiosis. In mitosis, the division of a "mother cell" generates two genetically identical "daughter cells" with the same chromosomal number that existed in the mother cell.
Partitioning in two copies is called cytokinesis and occurs in the animal cell from the outside inwards, that is, as if the cell were strangled and split in two (centripetal cytokinesis). There is a distribution of organelles across the two sister cells. Note that cytokinesis is actually the division of cytoplasm.
Golgi complex and protein storage It is the cellular organelle that stores part of the proteins produced in a cell, among other functions. These proteins can then be used later by the body. They are organelles that contain substances necessary for cellular digestion. When the cell encompasses a food particle that needs to be digested, the lysosomes go to it and release the digestive juice they contain.
Working like a bomb, the heart contracts and expands. Putting your ear to a colleague's chest, for example, you should easily hear the heartbeat. The contraction of the heart musculature is called systole, relaxation is called diastole. First, atrial systole occurs: blood passes to the ventricles.
Teeth cut, hold and grind food. In an adult human being, there are 32 teeth, sixteen in each dental arch, distributed as follows: Four incisors — located in front, two on the left, and two on the right — that cut the food; Two canines - also called “prey” on either side - that pierce the food; Four premolars - two on each side - that mash the food; Six molars - three on each side - which also crush food; Of these, the third or last molar (the wisdom tooth) may never be born.
There are various techniques for preserving foods so that they do not spoil, lose their nutritional value, or undergo any kind of alteration. The main ones are: boiling, cooling / freezing and dehydration. Boil Cooked foods stay longer than raw foods, because boiling kills the microorganisms contained in the food.
Muscle tissue cells are called muscle fibers and have the ability to contract and lengthen. We call this property contractility. These cells have the elongated shape and promote muscle contraction, which allows the various movements of the body. Muscle tissue can be of three types: smooth muscle tissue, skeletal striated muscle tissue and cardiac striated muscle tissue.
Urinary System What the body does not assimilate What the body does not assimilate, that is, materials that are useless or harmful to its functioning, must be eliminated. Observe, for 24 hours, everything that your body eliminates - the waste - will certainly appear: feces, urine, sweat… Are the materials that are unnecessary to the functioning of your body and expelled by it the same?
After approximately nine months, about 40 weeks after the act of fertilization, the fetus has developed and is ready to live outside the womb, which is no longer able to maintain and protect it. It's time to be born. In general, the time of childbirth is surrounded by much expectation, anxiety and even fear, which causes a great excitement of the pregnant woman especially the one who is giving birth to her first child.
Our ears also help us realize what is happening around us. In addition to perceiving sounds, they also give us information about the position of our bodies and are partly responsible for our balance. The auditory pavilion (outer ear) concentrates and picks up the sound so we can hear the sounds of nature, differentiate the sounds coming from the sea from the sound coming from a car, the strong and weak sounds, bass and treble.
Notice the figure below that shows the passage from adolescent to adult woman. Some of the changes in this passage are breast enlargement and the appearance of pubic hair and underarm hair. These are some of the secondary female sexual characteristics. Before we talk about the interior of the female body, let's talk about the outside, through which the woman receives stimuli and relates to the environment.
An international commission of taxonomists selected the top 10 species discovered in 2015 from about 18,000 new species named during the previous year. The list was released to coincide (roughly) with the birthday of Carolus Linnaeus (May 23), considered the father of modern taxonomy.
You are probably afraid of some animals, right? Especially because many of them are known to be very dangerous. When it comes to what causes panic, some factors are considered as the claws and fangs of some pets that inhabit our planet. Check it out below and tell us: would you face one of these animals head on?
When we are sick, our immune system becomes weaker than normal. In the case of influenza, when it occurs, we need to stay hydrated, which helps relieve sore throat and nasal congestion. What alcoholic beverages do is just the opposite: dehydrate. So, especially in the early stages of the flu, doctors recommend avoiding alcohol, as it can cause dehydration and make the situation worse, increasing cough, sore throat and nasal congestion.
Encourage the implementation of projects that reduce greenhouse gas emissions in Annex I countries with transition economies. The rules regarding project methodologies, project types and steps are similar to those in the "Clean Development Mechanism". What is my contribution to the greenhouse effect?