Plant cytology

Each tissue and region is composed of various differentiated cell types which together provide for the functions achieved in the tissues. Several different cell types can be observed in plants.
There are wax-coated dermal cells, isodiametric parenchyma and elongate collenchyma ground tissue cells. Some of the latter are sclerenchyma cells. Each of these have a range of structural and functional features that distinguish them .
The hollow tracheary elements of xylem are most closely related to sclerenchyma in structure and function. The living sieve tube elements are most closely related to parenchyma in structure and function, but are clearly more derived. The sieve tube elements typically lose their membrane-bound organelles including nucleus, mitochondria, and plastids. An adjacent complete parenchyma-type cell, called the companion cell keeps the cytoplasm of the sieve tube element alive through plasmodesma connections.

What is it that all plant cells have in common?

To be honest, perhaps there is nothing. Some cells lack cell walls (plant sperm cells, for example) and other cells lack everything else (xylem vessel element, for example). But because of cells that are dead at functional maturity, the best answer would probably be the cell wall. In consideration of the sheer mass and volume of dead cells in the trunk of a Sequoia tree, for example, a dead cell might arguably be more "typical" than what is often depicted as a "typical" plant cell in textbooks.

Because a parenchyma cell is alive and is responsible for virtually all of the photosynthesis and respiration in a plant, most books will show the parenchyma cell as "typical." Below is a cartoon of what a parenchyma cell looks like in an electron microscope view. This cell could be, for example, a spongy mesophyll cell from a leaf.

The cell wall is more than just cellulose

Many people know that the cell wall is made of layers of variously arranged/aligned cellulose microfibrils. But this polymer of glucose is not the only wall element by any means! In addition to cellulose, walls have a range of various polymers of sugars and sugar-derivatives. Hemicellulose rhamnogalacturonan, and pectins are shown here.

What is Cytogenetics?

Cytogenetics
is a branch of genetics that is concerned with the study of the structure and function of the cell, especially the chromosomes. It includes routine analysis of G-Banded chromosomes, other cytogenetic banding techniques, as well as molecular cytogenetics such asfluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH).
Cytogenetics is a field under genetics that mainly focuses on the cell, its structure, and how its parts function. It also particularly concentrates on the chromosome and how they are related to several hereditary disorders. Researches and experiments under the field of cytogenetics usually involve defected chromosomes that can tell how disorders and diseases are instigated.
The establishment of how many chromosomes are present in a human led to the emergence of cytogenetics. The discovery that some diseases are consistently indicated by some chromosomal changes was also a great factor in making cytogenetics an important field of research. Since then, many technological and chemical processes have been invented to aid the observation and analysis of chromosomes. Among these processes are the commonly-used comparative genomic hybridization (CGH) and the fluorescence “in situ” hybridization (FISH).
Both CGH and FISH often involve laboratory work, so cytogeneticists are technicians and scientists who are usually “behind the limelight,” so to speak, making sure that doctors get the correct information about a certain disease. 

• FISH is a technique that makes chromosomes light up using fluorescent molecules in order to specify any anomalies in the chromosome arrangement. These anomalies would usually show up in a different color than those of normal chromosomes.

• CGH, on the other hand, is a method that can spot any disturbing changes in the chromosomes, such as in samples from malignant cysts. In both methods, samples are often observed under the microscope, since chromosomes are very minute.

Chromosome samples are extracted from blood, amniotic fluids, biopsies of tumors, and bone marrow. Even tissues from skin and a baby’s umbilical cord can be used to obtain samples. These samples would then be cultured to multiply the cells, and when there are enough cells, the samples would be inserted in a machine called the centrifuge that separates the sample cells from other materials that will not be used in the analysis. The sample cells are then placed on the slide using a dropper and aged for several days, after which the sample is ready to be analyzed.
Role of  Cytogenetics

• Cytogenetics plays a significant role in the medical field, as laboratory results help doctors diagnose a disease and decide on the best treatment for the patient. 
• This field is especially helpful for hereditary and congenital disorders such as mental retardation, Down syndrome and Edward’s syndrome. 
• Cancer and infertility can also get better diagnosis and treatment. 
• Cytogenetics has also been a vital factor in preventing people from getting cancer by looking at gene predictors that indicate the chances of obtaining cancer.

What is Cytology?

cytology

is a branch of biology dealing with the structure, function, multiplication, pathology, and life history of cells  or it may be defined as the branch of life science which deals with the study of cell in terms of structure,function and chemistry.

Cytology 

More commonly known as cell biology, studies cell structure, cell composition, and the interaction of cells with other cells and the larger environment in which they exist. The term "cytology" can also refer to , cytopathology,which analyzes cell structure to diagnose disease. Microscopic and molecular studies of cells can focus on either multicellular or single-cellular organisms.

That fact that we as humans are made up of millions of tiny cells, and that other lifeforms around us are similarly constituted, now barely needs explanation. The concept of the cell is relatively new, however. The scientific community did not accept the idea of the existence of cells until the late 18th century. Cytology became, in the 19th century, a way to describe and identify cells, and also to diagnose certain medical diseases.

Recognizing the similarities and differences of cells is of the utmost importance in cytology. Microscopic examination can help identify different types of cells. Looking at the molecules which form a cell, sometimes called molecular biology, helps in further description and identification. All fields of biology depend on the understanding of cellular structure. The field of genetics exists because we understand cell structure and components. 

Another important aspect in the discipline of cytology is examining cell interaction. By studying how cells relate to other cells or to the environment, cytologists can predict problems or examine environmental dangers to cells, such as toxic or cancer-causing substances. In humans and other multicellular structures, cytology can examine the presence of too many of one kind of cell, or the lack of enough of a certain kind of cell. In a simple test like a complete blood count, a laboratory can look at white blood cells and identify the presence of an infection, or it may examine a low level of certain types of red blood cells and diagnose anemia.

Certain autoimmune disorders can be diagnosed by abnormal cell reactions. Hashimoto's thyroiditis, for example, is an autoimmune condition caused by abnormal cell reaction. Instead of white blood cells recognizing the presence of normal thyroid cells, these antibodies attack them, causing low thyroid. If untreated, this condition can result in retardation, extreme fatigue, obesity, and ultimately death. Through cytology, the abnormal reactions of these antibodies can be recognized, and treatment can be undertaken long before this condition creates irreversible problems.

Cyto pathology has similar aims, but tends to look for cells that should not be present in an organism. Urinalysis and blood tests, for example, can scan for the presence of parasites or bacteria which can cause illness and death. Hence, in cytology, understanding single-celled organisms like many forms of bacteria is as important as understanding multicellular structures.

This is also one of the main diagnostic tools for detecting cancer. A woman's yearly gynecological exam almost always involves a pap smear, a collection of tissues that are analyzed at the cellular structure to detect early formations of cancer cells. Early detection can lead to greater survival rates. Similarly, needle biopsies of lumps in the breast or elsewhere can detect cancer cells and provide an excellent means for diagnosis.

The recognition and the study of cells represent huge improvements in medical care and diagnostics. Cytology, by studying cell interaction, helps us to understand ways in which we can care for humans, animals and plants. Though biology precedes cytology in its development, cytologists are responsible for our modern view of biology and all other life sciences.