VITAL FUNCTIONS OF THE BODY

VITAL FUNCTIONS OF THE HUMAN

NUTRITION

Nutrition consists of all the processes through which a living thing obtains the substances it needs to live. Through nutrition, organisms obtain matter and energy. They are necessary to build new cells, to increase in size, to renew cells, to reconstruct lost parts etc. Energy is required to carry out some processes. 

There are two types of nutrition:

AUTROPHIC NUTRITION                                  HETEROTROPHIC NUTRITION

Autotrophic organisms make their own food by a process called photosynthesis. Green plants, for example, manufacture sugar and starch from carbon dioxide and water using the energy of sunlight to drive the necessary chemical reactions

Heterotrophic organisms obtain their food                                   from the bodies of other organisms. This is                                   done in various ways.                                  *Herbivores such as cattle, tortoises and                                       sparrows eat plants.                                  *Carnivores such as lions, crocodiles,                                           sharks and kestrels eat the flesh of other                                       animals.                                  *Omnivores such as humans can eat both                                     plants and animals.                                  *Saprophytes such as many types of                                             fungi and bacteria, obtain their food in                                         liquid form from the remains of dead                                           organisms.This feeding manifests itself                                         the process called decay.                                 * Parasites such as tapeworms and                                                 mosquitoes live on or in another living                                         organism (called the host) from which                                         they obtain food.

HUMAN NUTRITION (heterotrophic)

Cell nutrition
Everything begins when we consume food, from there a series of events happen in our organism that they lead to the cellular nutrition. The digestion, in his different phases, separates into its elements the food consumed in units simpler that can be used by the cells, as the glucose or the amino acids. These molecules are taken by the blood to the different cellular groups.

*Digestion of substances: once the nutrients are inside the cell, in the shape of vacuolas, are separated into its elements in units furthermore simple thanks to the enzimas that the lisosomas spill. These simpler substances cross the walls of the vacuolas and are distributed by the cytoplasm of the cell. *Metabolism: maybe the most important phase and for which everything previous has happened. It takes place in the cytoplasm. It consists of a series of chemical reactions that lead the production of energy that needs the cell to work and, in addition, to be synthesized organic essential substances for our body. The cellular metabolism possesses two fundamental processes:

-Catabolism: with the oxygen that we incorporate of the way and part of the organic matter generated during the digestion the biochemical energy takes place. In this process also there are generated compounds that the cell has to expel because they are toxic, as the carbon dioxide. The catabolismo also is known by the term of cellular breathing. B. 
-Anabolism: with the created energy and the organic simple substances, big organic molecules are synthesized. 
*Elimination of residues: already we mention that in the previous phases not only substances and indispensable energies take place for the life, but in addition compounds that can turn out to be toxins and that are expelled on the outside across the membrana celular.

Systems involved:

Digestive System

Your digestive system extends from your mouth to your anus and includes accessory organs such as your liver and gallbladder. This system breaks down food into vitamins, minerals and nutrients for use by all your other body systems.

Respiratory System

Your respiratory system starts at your nose and ends at the small alveoli in the lungs. The respiratory system requires oxygen and uses red blood cells to distribute this oxygen to all parts of your body.

Circulatory System

Your circulatory system carries blood to all parts of your body. 

Urinary System

Your kidneys and bladder are the main parts of the urinary, or excretory, system. Your kidneys filter waste from your blood and use water, sodium, magnesium and potassium to make adjustments to your body's acid-base balance. Water is also required to help the urinary system excrete waste products.

INTERACTION

Processes that allow living things to detect and to obtain information of the way in which they live, to take the decisions succeeded to answer to the environment and to be able to adapt and survive. The interaction links the living thing with the environment. The nervous system and the endocrine system are those who will collaborate in this function. The function of relation has three elements: the senses, the nervous system and the locomotive device. Thanks to them, the human being is integrated to his way of the one that obtains information across sensory recipients.

REPRODUCTION

The biological processes by which new individual organisms are produced from their parents. There are two major forms of reproduction: sexual and asexual.

Sexual reproduction

Sexual reproduction requires two parents. Each parent contributes a gamete - a sex cell that has half of the normal DNA of a regular body cell. In males, the gametes are sperm and in females, the gametes are eggs.

When these two gamete combine during fertilization, the result is a zygote, which then continues to develop into an embryo.

Asexual reproduction

Asexual reproduction requires only one parent.

There are many types of asexual reproduction. Four major types are:

1) Binary fission: Single parent cell doubles its DNA, then divides into two cells. Usually occurs in bacteria.

2) Budding: Small growth on surface of parent breaks off to continue growing into adulthood. Occurs in yeast and some animals (like the hydra below).

3) Fragmentation: Organisms break into two or more fragments that develop into a new individual. Occurs in many plants, as well as some animals (like cora, sponges, and starfish).

4) Parthenogenesis: An embryo develops from an unfertilized cell. Occurs in invertebrates, as well as in some fish, amphibians, and reptiles.

CELL REPRODUCTION:

  Cell reproduction is the process by which cells divide to form new cells.  Each time a cell divides, it makes a copy of all of its chromosomes,which are tightly coiled strands of DNA, the genetic material that holds the instructions for all life, and sends an identical copy to the new cell that is created.  This is a process called ''Mitosis''. Humans have 46 Chromosomes within each of their body cells.  Other species have different numbers of chromosomes

CELL CYCLE

During the G1 Phase, the cell grows and stores up energy that it will use during cell division. Nutrients are taken in and all the usual cell processes take place.  Once cells are fully grown, they proceed on to the S Phase.

During the S Phase, the DNA in the cell's nucleus is copied.  This means that the cell then attains two copies of all the necessary DNA for normal cell activity, leaving a full set to be transferred into the new cell that will be created after the cell divides. 

During g2 phase, the cell prepares for cell division.  This phase represents a time gap between the time when the cell copies its DNA and when it divides.  

 During M phase, cell division takes place through mitosis. 

During Cytokinesis, the cytoplasm in the cell divides and the cell's membrane pinches inward and the cell begins to divide.  Also, when plant cells divide, a cell plate forms between the two new cells to divide them.  After this step, the new cell and sometimes the original cell also restart the cell cycle by beginning G1 Phase again. 

MEIOSIS:

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores

MITOSIS:

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.