Animal cells range in size from a few microscopic microns to few millimetres. The largest known animal cell is the ostrich egg, which can stretch over 5.1 inches across and weighs about 1.4 kilograms. This is in stark contrast to the neuron in the human body, which is just 100 microns across.
The shape of animal cells also varies, with some being flat, others oval or rod-shaped. There are also more intriguing shapes such as curved, spherical, concave and rectangular. Most of the cells are microscopic in size and can only be seen under the microscope.
As stated before, animal cells are eukaryotic cells with a membrane-bound nucleus. Furthermore, these cells exhibit the presence of DNA inside the nucleus. They also comprise other membrane-bound organelles and cellular structures which carry out specific functions necessary for a cell to function properly.
Animal Cell Structure
Animal cells are generally smaller than plant cells. Another defining characteristic is its irregular shape. This is due to the absence of a cell wall. But animal cells share other cellular organelles with plant cells as both have evolved from eukaryotic cells.
A typical animal cell comprises the following cell organelles:
A thin semipermeable membrane layer of protein and fats surrounding the cell. Its primary role is to protect the cell from its surrounding. Also, it controls the entry and exit of nutrients and other microscopic entities into the cell.
It is a double-membrane structure that surrounds the nucleus. It is also referred to as the nuclear envelope.
It is an organelle that contains several other sub-organelles such as nucleolus, nucleosomes and chromatins. It also contains DNA and other genetic materials.
It is a small organelle found near to the nucleus which has a thick centre with radiating tubules. The centrosomes are where microtubules are produced.
Lysosome (Cell Vesicles)
They are round organelles surrounded by a membrane and comprising digestive enzymes which help in digestion, excretion and in the cell renewal process.
A jelly-like material which contains all the cell organelles, enclosed within the cell membrane. The substance found within the cell nucleus, contained by the nuclear membrane is called the nucleoplasm.
A flat, smooth layered, sac-like organelle which is located near the nucleus and involved in manufacturing, storing, packing and transporting the particles throughout the cell.
They are spherical or rod-shaped organelles with a double membrane. They are the powerhouse of a cell as they play an important role in releasing energy.
They are small organelles made up of RNA-rich cytoplasmic granules, and they are the sites of protein synthesis.
Endoplasmic Reticulum (ER)
This cellular organelle is composed of a thin, winding network of membranous sacs originating from the nucleus.
A membrane-bound organelle present inside a cell involved in maintaining shape and storing water, food, wastes, etc.
They are tiny holes present in the nuclear membrane which are involved in the movement of nucleic acids and proteins within the cell.
Animal Cell Types
There are numerous types of animal cells, each designed to serve specific functions. The most common types of animal cells are:
Melanocytes, keratinocytes, Merkel cells and Langerhans cells
Myocyte, Myosatellite cells, Tendon cells, Cardiac muscle cells
Leukocytes, erythrocytes, platelet
Schwann cell, glial cells etc
Learn all this useful information about the types of animal cells.