Parts of the animal cell

The animal cell is the basic functional unit of animal tissues , which are multicellular organisms . It is, like the plant cell, a type of eukaryotic cell characterized by having a true nucleus and specialized organelles, which differentiates it from prokaryotic cells. There is a wide variety of cells in animals, but did you know that there are more than 200 different classes in the human body? In the following, we describe the types of animal cells and their most characteristic functions , although they are not present in all animals.

• Epithelial cells: these are normally the cells that are present in the walls of the organs, forming the covering tissues. They present different specializations according to the body in which they are, since this specialization determines their function. For example, the cells of the epithelium of the small intestine present microvilli to increase the absorption surface of nutrients.
• Nerve cells: Two types of cells make up nervous tissue: neurons and glia cells. Neurons are those that are specialized in the transmission of the nerve impulse through the synapse between neurons or between neuron and muscle cell. Glial cells, on the other hand, do not transmit nerve impulses, but serve as support and maintenance for neurons. Due to their function, both have a branched or star shape, which facilitates communication between them.
• Muscle cells: There are three main types of muscle cells: those of smooth muscle tissue, skeletal and cardiac. They have the characteristics that they are contractile because they have the ability to transform chemical energy into mechanical energy. The forms of these cells are varied since, depending on the tissue they form, they have one function or another. Those of smooth muscle are elongated in appearance, those of skeletal and cardiac have striae, but the latter are characterized by an involuntary rhythmic contraction.
• Blood cells: There are three different types of blood cells: red blood cells (or erythrocytes), white blood cells (or leukocytes), and platelets. Erythrocytes are the most peculiar, because they are the only cells in the human body that do not have a nucleus. These cell types generally move through the bloodstream and serve for the transport and exchange of oxygen and CO2 (red blood cells), production of antibodies for the immune response (white blood cells) or clotting for the maintenance of the circulatory system.
• Fat cells: these are adipocytes, large cells whose function is to store energy in the form of fatty acids inside, secrete proteins and hormones and function as thermal and mechanical protection.
• Cartilaginous cells: they are called chondrocytes and have a flattened and rounded shape and the presence of microvilli. In the human body, these cells are present in tissues found in the ribs, joints, nose … and together they have a support function.
• Bones: they are responsible for the growth of the bone and its degradation. There are three types: osteoblasts, osteoclasts, and osteocytes.

Apart from knowing these functions of animal cells and their types, we also recommend reading this other article on the Types of animal tissues .

In order to know the main characteristics of the animal cell, it is convenient to begin by learning what its parts and functions are. In summary, this is the list of the parts of the animal cell :

• Core
• Plasma membrane
• Cytoplasm
• Endoplasmic reticulum
• Golgi apparatus
• Centrosome
• Cilia and flagella
• Mitochondria
• Cytoskeleton

Apart from continuing to read this article to learn details about the characteristics and functions of the parts of the animal cell , we also advise you to read this other post about the Difference between a eukaryotic cell and a prokaryotic cell .

It is the organelle specialized in processing and managing the information of the cell. Normally, eukaryotic cells have only one nucleus , but there are exceptions where we can find more than one. The shape of this organelle varies depending on the cell in which it is found, but it is generally round in appearance. In it, the genetic material is stored in the form of DNA (deoxyribonucleic acid) and it is in charge of coordinating the activities of the cell: from its growth to reproduction. The nucleus, in addition, has a visible structure called nucleolus inside it, which is formed by the concentration of chromatin and proteins. Mammals have a number between 1 and 5 nucleoli in the cell.

The plasma membrane is the structure that surrounds the cell and is present in all living cells. It is responsible for encompassing their content and protecting them from the outside environment, which does not mean that it is a hermetic membrane, since it has pores and other structures through which certain molecules pass necessary to carry out the internal processes of the cell. animal.

The cytoplasm of animal cells is the space between the cytoplasmic membrane and the nucleus, which surrounds all organelles. It is made up of 70% water and the rest is a mixture of proteins, lipids, carbohydrates and mineral salts. This medium is vital for the development of cell activity.

The endoplasmic reticulum is an organelle that is shaped like flattened sacs and stacked tubules that share the same internal space. The reticulum is organized into several domains that are: the rough endoplasmic reticulum , with flattened membranes and associated ribosomes, and the smooth endoplasmic reticulum , with a more irregular appearance and without associated ribosomes.

It is a set of membranes in the form of cisterns in charge of the distribution and delivery of the cell’s chemicals, that is, it is the center of cellular secretion. It is similar in form to the complex or Golgi of plant cells , consists of three parts: the membranous sacs, tubules, where the substances are sent to the inside and outside of the cell, and, finally, the vacuoles.

The centrosome is characteristic of the animal cell and is a hollow, cylindrical structure composed of two centrioles arranged perpendicular to each other. The composition of this organelle is made of protein tubules and has a very important function in cell division , since it organizes the cytoskeleton and gives rise to the achromatic spindle during mitosis . It can also cause cilia or flagella.

The cilia and flagella of the animal cell are appendages formed by microtubules that give mobility to the cell . They are present in unicellular organisms and are responsible for their locomotion and in other cells they serve to remove the environment or for sensory function. In terms of number, the cilia are more abundant than the flagella.

The mitochondria are the cell organelles animal which arrive nutrients are transformed into energy , in a process called respiration. They are elongated in shape and have two membranes: an internal one that folds into ridges and a smooth external one. The number of mitochondria present in each cell depends on its activity (for example, in muscle cells there will be a high number of them).

To finish off the list of the main parts of animal cells, we mention the cytoskeleton . It is formed by a set of filaments found in the cytoplasm and has a support function for organelles, in addition to the function of shaping the cell .

As we have already talked about which are the parts of the animal cell and their functions , now we will clarify that, although there are some characteristics and organelles that animal and plant cells have in common, the truth is that they present clear differences. These are the main differences between an animal cell and a plant cell :

• The most characteristic is that the animal cell can be found only in living beings of the animal kingdom and the plant cell is present only in plants and algae.
• On the other hand, the animal cell does not have an external cell wall or chloroplasts.
• One of the parts of the animal cell that the plant does not have is the centrosome and, in addition, it has more numerous vacuoles inside.
• In addition, the presence of cilia or flagella is also more frequent in animal cells, since in plants only cilia usually appear in the gamete phase of some plants or algae.