Human Cell

Introduction

The structural and functional unit of life is a cell. The study of basic function and structure of each cell organ is known as cell biology. The first scientist who discovered the cell was Robert Hooke in 1665. Every organism is made of cells. Cells can be either a single cell or many cells. Cell components perform various functions in an organism and are complex. Human body is made up of different types of cells, sizes and shapes. These different varieties of human cells help the human body to do various activities.

Structure of Human Cell

Cells have distinct types and thus they can look wildly different, and carry out different roles within the body. For example, a sperm cell looks like a tadpole, a female egg cell is spherical in shape and nerve cells are essentially thin tubes. Despite the differences, certain structures called the organelles are found common in all types of cells.

Centrioles

In the cytoplasm of the cell, the barrel shaped organelles are known as the centrioles which have an important role in our body’s skeletal system.

Lysosomes

The membrane-bound cell organelle that contains digestive enzymes is known as lysosomes. Lysosomes are involved with various cell processes, like breaking down excess or worn-out cell parts.

The nucleus

The nucleus can be considered as the headquarter of the cell. Normally there is one nucleus per cell but in skeletal muscle cells there are two nucleuses. The majority of the cell’s DNA contains the nucleus. The nucleus conveys the messages to the cell to grow, divide, or die.

The cytoplasm

The cytoplasm is in the interior part of the cell that surrounds the nucleus and is around 80 percent water. It includes all the organelles and a jelly-like fluid called the cytosol. The cytoplasm is the place where many important reactions take place.

Plasma Membrane

Cells are enveloped in a special membrane known as the plasma membrane made of phospholipids to ensure each cell remains separate from its neighbouring cell. These organelles perform various tasks as they contain a range of receptors.

Endoplasmic reticulum

Endoplasmic reticulum processes molecules within the cell and helps transport them to their final destinations. In particular, it synthesises, folds, modifies, and transports proteins. The types of endoplasmic reticulum are: the smooth endoplasmic reticulum (SER) and the rough endoplasmic reticulum (RER).

Golgi apparatus

Molecules which once have been processed by the endocrine travel to the Golgi apparatus. It is sometimes considered the post office of the cell where items are packaged and labelled. 

Mitochondria

Referred to as the powerhouse of the cell, mitochondria functions to turn energy that we get from the food that we eat into energy that the cell can use that is adenosine triphosphate (ATP). However, mitochondria have a number of other functions, like calcium storage and a role in cell death.

Ribosomes

In the nucleus, DNA is transcribed into RNA (ribonucleic acid) which is a molecule similar to DNA, that carries the same message. Ribosomes read the message of the RNA and then translate it into protein by sticking together amino acids in the order defined by the RNA.

Functions of human cell

Human body consists of numerous cells and thereby there are various types of cells present in a human body that perform various functions.

Stem Cells

Every cell before becoming a specialised cell, comes out as a stem cell. The distinct property of stem cells is that they can become any type of cell in the body. The two types of stem cells, embryonic stem cells, arise from embryos and adult stem cells are harvested from fertilised eggs.

Red Blood Cells

The most common type of blood cells are the RBCs. Haemoglobin present in red blood cells binds oxygen allowing it to be transported through the blood.

White Blood Cells

White blood cells(WBCs) are the vital part of our body’s immune system which fight against external diseases and infection.

Nerve Cells

The nervous system comprises the nerve cells. The nerve cells transmit information throughout the body in the form of electric signals.

Muscle Cells

These cells are long and tubular cells. They provide a variety of functions such as movement, support and certain internal functions such as peristalsis.

Sex Cells

They are the smallest cells present in the human body. They are tadpole-shaped cells and have a tail like structure called flagellum which helps them to move. They are the central part of human reproduction.

Fat Cells

They are also called adipocytes and are the main constituent in adipose tissue. They contain stored fats called triglycerides which can be used as energy when needed. 

Conclusion

Cells constitute the most vital unit of living beings. All living organisms are dependent on the structural and functional unit of cells. The different structures and functions of the human cells helps the human body in all activities like reasoning, movement, etc. There are an enormous number of cells present in a human body, each involved with various activities. Cells store genetic materials in living organisms and are also a site for various metabolic activities.