Search Results for: passage
Alimentary canal
Definition of Alimentary canal What is the alimentary canal? The alimentary canal is a muscular hollow continuous tubular... Read More
Permeability
Permeability Definition What is permeability? In earth science, its definition is this: "the ability of any material such... Read More
Facilitated diffusion
Facilitated diffusion is the transport of substances across a biological membrane from an area of higher concentration to an... 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
Dead Man Walking
Dead Man Walking: Wade Davis and the Secret of the Zombie Poison By Patrick D. Hahn Accepted on September 4, 2007 Twenty... Read More
Circulation
Blood Blood is composed of a liquid, plasma, and blood cells such as erythrocytes (red blood cells,) leukocytes (white... Read More
Phospholipid
What is a phospholipid? Phospholipids are a subgroup of lipids. Other major types of lipids are fatty acids, sphingolipids,... Read More
Nuclear pore complex
Definition noun plural: nuclear pore complexes ˈnu kli ər, pɔː ˈkɒmplɛks A complex of nucleoporins resulting in the... Read More
Nuclear envelope
Definition noun plural: nuclear envelopes nu·cle·ar en·ve·lope, ˈn(j)ukliɚ ˈɛn.və.ləʊp The two layered membrane... Read More
Nuclear pore
Definition noun plural: nuclear pores ˈnu kli ər, pɔː Any of the many perforations on the nucleus as a result of the... Read More
Semilunar valve
The human heart structure consists of heart chambers (2 atria and 2 ventricles) that differ functionally from each other.... Read More
Electrical synapse
Definition noun A form of synapse between two apposed neurons in which nerve impulse transmission is rapid and occurs by... Read More
Tight junction
What are tight junctions? Tight junctions are the intercellular barrier between two neighboring endothelial and epithelial... Read More
Blood-brain barrier
Definition noun A semipermeable membrane that serves as a selective barrier separating the circulating blood and the... Read More
Cell membrane permeability
Cell membrane permeability a quality of cell membranes which permits the passage of solvents and solutes into and out of... Read More
Inhibitory postsynaptic potential
Inhibitory Postsynaptic Potential Definition An inhibitory postsynaptic potential is a type of synaptic potential. It is... Read More
Kidney calices
Definition noun, singular: kidney calyx Funnel-shaped structures that allow passage of the urine from the ducts of the renal... Read More
Light-dependent reaction
Many organisms, such as green plants, convert light energy into chemical energy through the mechanism of photosynthesis. In... Read More
Polymorphism
Polymorphism Definition The occurrence of two or more different forms or morphs in the population of a species is referred... Read More
Cyclic adenosine monophosphate
Definition noun plural: cyclic adenosine monophosphates (biochemistry) A cyclic form of adenosine monophosphate that... Read More
Semipermeable membrane
Definition noun A membrane that is selectively permeable, i.e. being permeable to only certain molecules and not to all... Read More
Scalene hiatus
scalene hiatus triangular gap bounded by the scalenus anterior and scalenus medius muscles and the first rib to which the... Read More
Plasmodesmata
Plasmodesmata (singular, plasmodesma) microscopic channels of plants facilitating transport and communication between... Read More
Osteoporosis
Definition noun, plural: osteoporoses A disease of bone in which the bones become extremely porous and are subject to... Read More
Adenosine monophosphate
Definition noun plural: adenosine monophosphates (biochemistry) A nucleotide composed of adenine, ribose and a phosphate... Read More
Feedback mechanism
Feedback Mechanism Definition What is a feedback mechanism? A feedback mechanism is a physiological regulation system in a... Read More
Selective permeability
Definition noun A feature and a function of the plasma membrane that is essential to maintain homeostasis by regulating the... Read More