Search Results for: barrier
Blood-brain barrier
Definition noun A semipermeable membrane that serves as a selective barrier separating the circulating blood and the... Read More
Tight junction
What are tight junctions? Tight junctions are the intercellular barrier between two neighboring endothelial and epithelial... Read More
Blood-air barrier
Blood-air barrier The barrier between capillary blood and alveolar air comprising the alveolar epithelium and capillary... Read More
Integumentary system
Integumentary System Definition The integumentary system is the outermost layer of the body. The animal body, in... Read More
Allopatric speciation
We can define speciation as a process by which the novel genetically independent group of organisms are formed through the... Read More
Plasma membrane
Do all cells have a plasma (or cell) membrane? Yes, all cells have a biological membrane that separates the protoplasm from... Read More
Birth Control and Contraception
Birth Control Some religious beliefs see methods of contraception unethical while some political bodies chose birth control... Read More
Sarcolemma
Sarcolemma Definition What is the sarcolemma? It is the thin, transparent, extensible plasma membrane of the muscle cell.... Read More
Glycocalyx
What is the Glycocalyx? The glycocalyx is a polysaccharide-based gel-like, highly hydrous cellular thin layer, covering... Read More
Endomembrane system
Ever wondered how biomolecules are made within the cell and then they are released outside the cell for use by the body?... Read More
Sympatric speciation
Speciation is a process of evolution through which two different existing populations evolve and a distinct species form. It... Read More
Selectively-permeable membrane
Selectively Permeable Membrane Definition We can define selectively permeable membranes as those that are selectively... Read More
Cell adhesion
Cell Adhesion Definition Cell adhesion is the process in which a cell uses a specialized complex of proteins to get... Read More
Nervous tissue
Nervous Tissue Definition Nerve cells (or neurons) and their associated cells, such as neuroglia cells, make up nervous... Read More
Biological Cell Defense
Organisms must find a means of defense against antigens such a viruses described on the previous tutorial. If this was not... Read More
Group translocation
Group Translocation Definition Just like your âhomeâ is a private place where you and your comfort are maintained due... Read More
Cork cambium
Cork Cambium Definition Cork cambium is a secondary meristematic tissue that has a pivotal role in secondary growth in... Read More
Cornification
Definition noun, plural: cornifications The process of forming a keratinized, horny layer of epidermis cornified,... Read More
Cell membrane
Cell Membrane Definition Just like any non-living body possesses a plastic or paper packaging material that keeps the... Read More
Cell Structure
The interior of human cells is divided into the nucleus and the cytoplasm. The nucleus is a spherical or oval-shaped... Read More
Neural Control Mechanisms
Nerve cells called neurons generate electric signals that pass from one end of the cell to another and release chemical... Read More
Respiration
Organization of the Respiratory System Each lung is composed of air sacs called alveoli - the sites of gas exchange with... Read More
Amphipathic
Amphipathic Definition Amphipathic is a word used to describe a chemical compound containing both polar (water-soluble) and... Read More
Genetic variability
Genetic Variability Definition Genetic variability refers to the tendency of individual genetic characteristics in a... Read More
Vicariance
Definition noun, plural: vicariances (biology) The separation of a large group of organisms from the population due to a... Read More
Stratum corneum
Definition noun The outermost layer of the epidermis comprised of corneocytes and accounts for most of the protective... Read More
Biological Cell Introduction
It only takes one biological cell to create an organism. In fact, there are countless species of single-celled organisms,... Read More
Plant Cell Defense
Hydrogen Peroxide Plants release hydrogen peroxide in response to the presence of a fungal invasion, which attacks by... Read More
Simple squamous epithelium
Simple Squamous Epithelium Definition Simple squamous epithelium, also known as simple squamous epithelial tissue or... Read More
Keratinocyte
Definition noun, plural: keratinocytes The predominant type of cell in the epidermal layer of the skin Supplement The skin... Read More
Sebaceous gland
Definition noun, plural: sebaceous glands An exocrine gland secreting sebum that lubricates hair and skin Supplement A... Read More
Scleroprotein
Definition noun, plural: scleroproteins A type of protein characterized by being fibrous and its function which is to... Read More
Alimentary canal
Definition of Alimentary canal What is the alimentary canal? The alimentary canal is a muscular hollow continuous tubular... Read More
Hemorrhagic exudate
Definition noun A type of exudate that is bloody because of the large component of red blood cells released from ruptured... Read More