Histology - tissues I

Histological technique

The process of preparing tissue samples for microscopic examination.

Fixation

Chemical preservation of tissues to prevent disintegration and prepare them for further processing.

Dehydration

Removal of free water from tissues to prepare them for embedding in hydrophobic substances.

Clearing

Removal of dehydration substances from tissues to make them translucent or transparent.

Impregnation

Treatment of tissues with stiffening substances, such as paraffin, to allow thin sectioning.

Staining

Application of different dyes to highlight specific structures in tissues.

Diversity of human cells

Variations in shape, nucleus position, special features, and location to other cells.

Factors determining morphology

Environment, functions, and cytoskeleton influence the shape of cells.

Epithelial tissue

Tissue that covers and lines organs, characterized by polarized cells and specialized structures.

Connective tissue

Tissue that supports and connects other tissues, composed of cells and extracellular matrix.

Muscle tissue

Tissue responsible for movement, characterized by contractile cells.

Nerve tissue

Tissue that transmits and processes information, composed of neurons and supporting cells.

Basement membrane

Thin layer that separates epithelial cells from other tissues and provides support.

Intercellular junctions

Specialized structures that connect epithelial cells and strengthen tissue.

Specialized structures of apical pole

Microvilli, stereocilia, and cilia that increase surface area or facilitate movement.

Stratified squamous nonkeratinized epithelium

Moist epithelium found in oral cavity, vagina, esophagus, anus, and cornea.

Stratified squamous keratinized epithelium

Dry epithelium found in the epidermis of the skin.

Transitional epithelium

Stretchable epithelium found in the calyces of kidneys, ureters, and bladder.

Glandular epithelium

Epithelium specialized for secretion, either endocrine or exocrine.

Unicellular glands

Goblet cells that secrete mucus in the airway and intestine.

Basal pole

The region of a cell or tissue that contains organelles and the nucleus.

Apical pole

The region of a cell or tissue that contains secretory granules.

Simple glands

Glands that have one duct and a secretory portion.

Compound glands

Glands that have a duct with branches and a secretory portion.

Tubular secretory portion

A secretory portion of a gland that is shaped like a tube.

Acinar secretory portion

A secretory portion of a gland that is shaped like a sac or acinus.

Tubuloacinar secretory portion

A secretory portion of a gland that has both tubular and acinar structures.

Merocrine secretion

A type of secretion where the cell secretes its contents without affecting the cell itself.

Apocrine secretion

A type of secretion where the cell secretes its contents and loses part of its cytoplasm and plasma membrane.

Holocrine secretion

A type of secretion where the cell disintegrates upon secretion.

Connective tissue

A type of tissue that provides support and connects different structures in the body.

Fat tissue

A type of connective tissue that provides padding and insulation.

Bone tissue

A type of connective tissue that forms the skeleton and provides support.

Tendon

A type of connective tissue that connects muscle to bone.

Blood

A type of connective tissue that transports oxygen, nutrients, and waste products throughout the body.

Cartilage

A type of connective tissue that provides support and flexibility to certain structures in the body.

Fibrous connective tissue

A type of connective tissue that is found between cells and structures and does not have a specific function.

Collagen

A type of protein that is the main component of connective tissue and provides strength and support.

Loose connective tissue

A type of fibrous connective tissue that has a loose arrangement of fibers and cells.

Dense connective tissue

A type of fibrous connective tissue that has a dense arrangement of fibers and cells.

Regular connective tissue

A type of dense connective tissue that has fibers arranged in a parallel fashion.

Irregular connective tissue

A type of dense connective tissue that has fibers arranged in a random fashion.

Elastic connective tissue

A type of connective tissue that contains elastic fibers and provides elasticity to certain structures in the body.

Specialized connective tissue

A type of connective tissue that has specific functions and characteristics.

Blood and lymph

Specialized connective tissues that transport fluids and immune cells throughout the body.

Adipose tissue

Specialized connective tissue that stores fat and provides insulation and padding.

Reticular tissue

Specialized connective tissue that forms a network or framework for other cells and structures.

Skeletal tissue

Specialized connective tissue that forms the skeleton and provides support and movement.

Cartilage

Specialized connective tissue that provides support and flexibility to certain structures in the body.

Extracellular matrix

The non-cellular component of connective tissue that provides structural support and regulates cell behavior.

Ground substance

The watery or gelatinous component of the extracellular matrix.

Glycosaminoglycans (GAGs)

Long chains of disaccharides that are the main component of the ground substance.

Proteoglycans

Chains of amino acids that are connected to GAGs and provide additional support and stability to the extracellular matrix.

Glycoproteins

Proteins that have carbohydrate chains attached to them and help strengthen and stabilize tissues.

Collagen fibers

Fibers made of collagen protein that provide strength and support to connective tissues.

Elastic fibers

Fibers made of elastin and fibrillin proteins that provide elasticity to certain structures in the body.

Reticular fibers

Fibers made of type III collagen that form a network in immune system and hematopoietic tissues.

Fibroblasts

Resident cells in connective tissue that actively synthesize components of the extracellular matrix.

Fibrocytes

Cells derived from fibroblasts that do not actively synthesize components of the extracellular matrix.

Reticular cells

Cells in reticular connective tissue that synthesize type III collagen and partially cover fibers with their cytoplasmic processes.

Pericytes

Star-shaped cells that can contract and are located next to capillaries.

Mast cells

Cells with basophilic granules that synthesize bioactive substances involved in immune response, inflammation, and healing.

Adipocytes

Cells that accumulate and store lipids in adip

Langerhans cells

Cells found in the epidermis that play a role in immune protection.

Macrophages

Cells found in the lungs, nerve tissue, and synovial joints that protect against microbes, toxins, parasites, and cancer cells.

Diapedesis

The ability of cells to slip between capillary walls and reside in the plasma after being released from the bone marrow.

Chemotaxis

The movement of cells in response to a chemical signal.

Leukocytosis

An increase in the number of white blood cells in response to infection.

MHC (Major Histocompatibility Complex)

A group of proteins that bind to peptide fragments from antigens for recognition by T-cells and activation of an immune response.

B-cells

Cells that recognize antigens in their native form and free antigens in the blood or lymph using membrane-bound immunoglobulins.

T-cells

Cells that recognize antigens in a processed form, presented by an antigen-presenting cell's MHC molecule to the T-cell receptor.

Antigens

Genetically foreign materials that generate an immune response, such as proteins, viruses, foreign cells, and tumor cells.

Antibodies

Proteins (plasma globulins) that recognize antigens.

IgA, IgD, IgE, IgG, IgM

Different types of immunoglobulins (antibodies) with specific functions.

Blood platelets

Cell fragments that play a role in coagulation and attach to blood vessel walls.

Thrombocytopenia

A condition characterized by a reduced number of platelets.

Hemopoiesis

The process of blood cell formation.

Stem cells

Unspecialized cells with the ability to differentiate into different cell types.

Plasticity

The ability of stem cells from one tissue to transform into stem cells of another tissue.

Erythrocytes

Red blood cells that carry oxygen.

Granulocytes

A type of white blood cell involved in immune responses.

Megakaryocytes

Large cells in the bone marrow that give rise to platelets.

Monocytes

A type of white blood cell that can differentiate into macrophages.

Aplastic anemia

A condition characterized by a failure in bone marrow function.

Pancytopenia

A condition characterized by a low count of erythroid and myeloid series.

Lymph

A fluid similar to blood plasma that contains lymphocytes.

Cartilage

A type of connective tissue that provides support and flexibility to various structures in the body.

Hyaline cartilage

A type of cartilage found in the costal cartilage, articular cartilage, and respiratory tract.

Elastic cartilage

A type of cartilage found in the auricle of the ear, walls of the external auditory canal, and epiglottis.

Fibrocartilage

A type of cartilage found in the meniscus, pubic symphysis, and intervertebral discs.

Matrix

The extracellular substance of cartilage, composed of collagen or collagen and elastic fibers and ground substance.

Perichondrium

The connective tissue layer surrounding cartilage.

Osteoprogenitor cells

Spindle-shaped cells that differentiate into osteoblasts and are involved in bone growth and repair.

Osteoblasts

Cells that produce the organic components of bone and are involved in bone formation.

Osteocytes

Mature bone cells that maintain the bone matrix.

Osteoclasts

Multinucleated cells that resorb bone matrix.

Periosteum

The outer layer of bone that contains osteoprogenitor cells and is involved in bone growth and repair.

Endosteum

The thin layer of connective tissue lining the inner surface of bone.

Intramembranous ossification

The process of bone formation from mesenchymal cells, resulting in the production of flat bones.

Endochondral ossification

The process of bone formation from a hyaline cartilage model, resulting in the production of short and long bones.