Cell

1. All living things are composed by cells

2. Cell structures

2.1. Plasma membrane

2.1.1. Disorders

2.1.1.1. Red blood cells (RBCs) and usually inherited due to mutations in membrane leading to abnormalities within the RBCs, thus reducing their life span and early removal from circulation.

2.1.1.1.1. Hereditary conditions

2.1.1.2. Errors in the proteins located in the cell membranes

2.1.1.2.1. Muscular dystrophies

2.1.1.2.2. Dystrophinopathy

2.1.1.2.3. Bethlem myopathy

2.1.1.2.4. Merosinopathy

2.1.1.2.5. Dysferlinopathy

2.1.1.2.6. Sarcoglycanopathies

2.1.1.2.7. Caveolinopathy.

2.1.1.2.8. Receptor-related disorders

2.1.1.2.9. Altered lipid

2.1.1.2.10. Defective permeability of the membrane

2.1.1.2.11. Disease related to specific transport alterations

2.2. Protoplasm

2.2.1. Cytoplasm

2.2.1.1. Cytoskeleton

2.2.1.1.1. Defects

2.2.1.2. Also called plasma looks as though it is molded around the nucleus.

2.2.1.2.1. Cytoplasmic organelles will be floating within the cytoplasmic matrix (cytosol).

2.2.1.2.2. Macromolecules

2.2.1.2.3. Non-essential structures called inclusion bodies such as pigmented granules or stored fat droplets

2.2.1.3. Errors

2.2.1.3.1. Abnormally large amount of cytoplasm leads to defect in the chromosome alignment, spindle pole morphology, and checkpoint signaling leading to chromosome segregation errors.

2.2.2. Nucleus

2.2.2.1. The most rigid and largest cell organelle

2.2.2.2. Usually occupies the central portion of the cell

2.2.2.3. Surrounding the nucleus is a double-layered thin membrane called nuclear membrane

2.2.2.4. Nuclear pores that have selective permeability

2.2.2.5. Nucleoli

2.2.2.5.1. Non-membranous bodies made up of RNA that helps make ribosome

2.2.2.5.2. Heterochromatin consist of tightly coiled inactive chromatin (found in irregular clumps often around the periphery of the nucleus)

2.2.2.5.3. Euchromatin represents part of DNA that is active in RNA synthesis

2.2.2.5.4. Suspended is known as the nuclear sap

2.2.2.6. Defects

2.2.2.6.1. Mutation in the nuclear structure and composition

2.3. Organelles

2.3.1. With specific and unique functions

2.3.1.1. Golgi bodies

2.3.1.1.1. Irregular bodies present near the nucleus

2.3.1.1.2. They are observable under the light microscope by staining with silver salts. When observed under the electron microscope, one can appreciate that a single-layered membrane binds them in a ribbon-like fashion.

2.3.1.1.3. They help in protein biosynthesis and packaging protein molecules for export from the cell

2.3.1.1.4. Divided on

2.3.1.1.5. Defects

2.3.1.2. Mitochondria

2.3.1.2.1. Provide all the energy needed by a cell to move, divide, contract, produce secretory products, and all other functions of a cel

2.3.1.2.2. . Their size varies from 0.5 to 2 micrometers in length.

2.3.1.2.3. Membranes.

2.3.1.2.4. Mitochondrial cytopathy syndromes

2.3.1.3. Ribosomes

2.3.1.3.1. Many of them attach to the rough endoplasmic reticulum. And many of them are also seen scattered free throughout the cytoplasm.

2.3.1.3.2. Alone=monosomes in groups=polyribosomes.

2.3.1.3.3. Each of these ribosomes has subunits

2.3.1.3.4. They “translates” the DNA into proteins.

2.3.1.4. Lysosomes

2.3.1.4.1. Vesicles that pinch off from the Golgi apparatus

2.3.1.4.2. Storage diseases (LSDs)

2.3.1.5. Endoplasmic reticulum

2.3.1.5.1. Membrane channel made up of cisterns or tubules

2.3.1.5.2. The largest organelle

2.3.1.5.3. Protein synthesis

2.3.1.5.4. Calcium storage

2.3.1.5.5. Steroid synthesis

2.3.1.5.6. Lipid metabolism

2.3.1.5.7. Have different shapes cells involved in synthesizing excessive amounts of proteins have more sheets, and those involved in lipid synthesis have more tubules.

2.3.1.5.8. Different ER-shaping proteins diseases

2.3.1.6. Centrioles & Centrosomes

2.3.1.6.1. Essential structures that play in role in the cell division and replication.

2.3.1.7. Vesicles and Vacuoles

2.3.1.7.1. Act as the storage compartments of the cell. They usually hold proteins, wastes, food, etc. In the case of plant cells, they hold water within the vacuoles.

2.4. Inclusions

2.4.1. Enzimes

2.4.2. Proteins

2.4.3. Glucose

3. Histology

3.1. To study cells from any tissue requires a process

3.1.1. Tissue sampling

3.1.1.1. Obtained by surgical excision or biopsy, with the clearing of all connective tissue and undesired structures

3.1.1.1.1. Done by sharp instruments so that the actual structure of the cells/tissue under consideration does not become distorted.

3.1.2. Tissue fixation

3.1.2.1. Hardens the soft tissue and prevents any postmortem changes and distortion of the cells/tissues.

3.1.3. Dehydration

3.1.3.1. Pass the fixed tissue by increasing the strengths of alcohol until it reaches absolute alcohol.

3.1.4. Clearing

3.1.4.1. Remove the alcohol present in the tissue, with xylol.

3.1.5. Embedding

3.1.5.1. Pass through successive changes of warm paraffin so that all the spaces in the tissue occupied by xylol becomes replaced with paraffin wax.

3.1.6. Sectioning

3.1.6.1. Tissue sections are taken with an automated instrument called microtome, which gives fragile sections ranging from 1 to 9 micrometers.

3.1.7. Mounting and staining

3.1.7.1. The thin sections are mounted on the glass slides and washed with xylol to remove the paraffin wax.

3.1.7.1.1. Then it passed through decreasing strengths of alcohol and finally washed with water.

3.2. Histochemistry and Cytochemistry

3.2.1. Cytochemistry is the analysis, visualization, and identification of microanatomical locations of biochemical content and its environment, within a cell, providing discrete information about the ultrastructure and organelles of the cells, also of biochemical content.

3.2.1.1. By using electron microscopic techniques or biochemical analyses.

3.2.2. Histochemistry is the identification and distribution of chemical components within and between cells. Histochemical methods help with understanding the molecular basis of different pathologies and, most specifically, cancer progression, regularly assist in the diagnosis of metabolic disorders and several disease pathologies.

3.2.2.1. Use techniques like stains and indicators and employs light and electron microscopy to study the chemical constituents of the cells and tissues. The technique is imperative to visualize biological structures. Immunohistochemistry methods are also useful in elucidating nerve cell differentiation during development.Histochemical techniques can function as a method for regenerative and reparative medicine.

4. Mutation

4.1. Abnormalities in mitosis results from prolonged exposure to radiation (especially nuclear radiation). It can also happen with certain chemicals and drugs. But some cells do not undergo mitosis like a neural cell, cardiac cells. They are said to be in the Go stage.

5. Tumors

5.1. The rate of division of cells dramatically varies in different cells. It is highest in the epithelial cells exposed to friction. Rate correlates with demand.

5.2. Excessive uncontrolled growth leads to a condition commonly known as tumors.

6. Cell is the fundamental organizational unit of life.

6.1. In human body they are diverse in their sizes, function, structure and number

6.1.1. In adults there's a estimated fon 200 kind of cells

7. Types of cells

7.1. Eukaryotic

7.1.1. In animals and plants, definited nucleus

7.2. Prokaryotic

7.2.1. In bacteria and some algae, DNA spread in cytoplasm

8. Cells with similar structure and functions

8.1. Become tissues

8.1.1. Organ

9. Types of human cells

9.1. Stem cells

9.1.1. Primary cells

9.2. Muscle cells

9.2.1. Skeleton

9.2.2. Smooth

9.2.3. Cardiac

9.3. Bone cells

9.3.1. Osteocytes

9.3.2. Osteoclasts

9.3.3. Osteoblasts

9.4. Cartilage cells

9.4.1. Chondrocytes

9.4.2. Chondroblast

9.4.3. Chondroclasts

9.5. Blood cells

9.5.1. Platelets

9.5.2. Red blood cells, white blood cells,

9.5.3. Neutrophils

9.5.4. Basophils

9.6. Sex cells

9.6.1. Sperms

9.6.1.1. First they were spermatocytes,

9.6.1.2. Then they were secondary spermatocytes, spermatids

9.6.2. Ovum

9.6.3. Sertoli cells

9.6.4. Leydig cells,

9.6.4.1. hormone-secreting cells

9.7. Nervous cells

9.7.1. Neuron

9.7.2. Oligodendrocytes

9.7.3. Astrocytes

9.8. Fat cells

9.8.1. Lipocytes.

10. Functions

10.1. Structure

10.1.1. Give and mantein the shape and structure of the body.

10.2. Growth

10.2.1. The steam cells develope new types of cells, this is regulated by grow-promoting genes

10.3. Apoptosis

10.3.1. Self digestion, removal of the dead and worn out. It´s necessary for regeneration

10.4. Metabolism

10.4.1. Take place by the protein, carbohydrate and lipid synthesis to make cells grow

10.5. Regulation of temperature

10.5.1. Due the metabolism energy liberation

10.6. Communication

10.6.1. All cells comunnicate by enzymes, hormones or otthers

10.7. Transportation

10.7.1. Subtance across cytoplasm

10.8. Reproduction

10.8.1. Except for sexual cells, they need each other to form a zygote

11. Cell Cycle

11.1. Mitosis

11.1.1. Takes place in somatic cells (46 chromosomes)

11.1.2. Cells divide to produce two daughters that are exact copies of the mother cell

11.1.3. Prophase

11.1.4. Metaphase

11.1.5. Anaphase

11.1.6. Telophase

11.2. Meiosis

11.2.1. First division

11.2.1.1. Leptotene

11.2.1.2. Zygotene

11.2.1.3. Pachytene

11.2.1.4. Diplotene

11.2.2. Second Meiotic Division

11.2.2.1. The DNA content reduces to half. The daughter cells are not identical to the mother cell.

12. Pathophysiology

12.1. Double-stranded breaks (DSB) are the most toxic DNA lesions. If not repaired, or incorrectly repaired, they may result in loss of heterozygosity, single-stranded breaks, depurination, depyrimidination, O6 methylguanines, and cytosine deamination are similar types of DNA damages. If not corrected by the DNA repair system may lead to the development of pathologies.

12.1.1. The DNA damage response pathways that protect genome stability are inherently important to prevent neurodegeneration and malignant transformation of cells, in addition to the normal growth and development, immune development, and neurogenesis.

12.2. Repair systems

12.2.1. The repair system that corrects DNA damage includes, nonhomologous DNA end joining (NHEJ); NHEJ insufficiency can lead to the development of severe combined immunodeficiency.

12.2.2. Base excision repair (BER), single-strand break repair (SSBR); pathologies associated with the disorder of BER and SSBR include hyper IgM syndrome and colorectal carcinomas. Defective SSBR also presents with ataxias.

12.2.3. Homologous recombination (HR) and interstrand cross-link repair (ICL); disorder of HR and ICL can lead to the development of Fanconi anemia, familial breast cancer, and ovarian cancers.

12.2.4. Cyclin-dependent kinases (CDK) that are inherent to the regulation of the cell cycle also play an important role in DNA repair.

12.3. Hypertrophy

12.3.1. Muscle cells/fibers gain the muscle mass much excessive to their capacity, with no increase in the number of fibers, an overall increase in the size of the structure.

12.3.1.1. Seen in the pregnant uterus and muscles of the bodybuilders. This increase in muscle mass has been attributed to a protein growth factor called insulin-like growth factor 1 (IGF-1).

12.4. Hyperplasia

12.4.1. It is a condition where the cells divide rapidly in number leading to an overall increase in the size of the structure. It can be physiological or pathological.

12.4.1.1. Physiological type is the pregnant uterus. Pathologically it can be benign or malignant.

12.4.1.2. Benign prostatic hyperplasia (BPH) is the best example of benign hyperplasia. T

12.4.1.3. Endometrial hyperplasia in the endometrial carcinoma is not infrequent. Endometrial hyperplasia is a pathological state where the endometrial glandular tissue and stroma lining the uterus show severe hyperplastic changes.

12.5. Atrophy

12.5.1. Opposite of hypertrophy, wherein the cells start to shrink in size leading to an overall decrease in the size of a tissue or organ.

12.5.1.1. The thymus atrophy after mid-adulthood is a classic example of physiological atrophy.

12.5.1.2. Disuse atrophy is a term used for conditions where atrophy takes place in a specific tissue/organs after prolonged disuse of that particular structure. The atrophy of cells/tissues is due to an overall loss of cell organelles, proteins, and cytoplasm.

12.6. Metaplasia

12.6.1. Condition of change in cellular identity by a replacement of one type of healthy cells with other healthy cells type in a tissue/organ.

12.6.1.1. An abnormal stimulus induces it. This condition commonly presents in the lower end of the esophagus due to chronic gastroesophageal reflux.

12.7. Dysplasia

12.7.1. Condition where an abnormal arrangement of cells takes place due to a change in their usual growth behavior.