Biology

Semipermeable Membrane Definition A semipermeable membrane is a layer that only certain molecules can pass through. Semipermeable membranes can be both biological and artificial. Artificial semipermeable membranes include a variety of material designed for the purposes of filtration, such as those used in reverse osmosis, which only allow water to pass.  The biological membranes of … Read more

Phalanx Definition Phalanx (plural: phalanges) refers to the bones found in fingers, toes, paws, wings, hooves and fins of animals. These are long bones whose length exceeds their breadth. Phalanges are connected to each other at hinge-like inter phalangeal joints that can be used for either flexion or extension. Some phalanges are fused to each … Read more

Linked Genes Definition Linked genes are genes that are likely to be inherited together because they are physically close to one another on the same chromosome. During meiosis, chromosomes are recombined, resulting in gene swaps between homologous chromosomes. If genes are close together, the chances of being recombined are higher than if they are far … Read more

Definition The levator scapulae muscle (sometimes called the lev scap) is a strap-like muscle found on either side of the back of the neck. When viewed from the posterior, the muscles are masked by the trapezius muscle in the upper back. There are two of these muscles, one on the left, and one on the … Read more

Definition The cephalic vein is a superficial vein in the upper arm that is often visible through the skin. The name means head (likely coming from the Latin ‘cephalicus’ or the Greek ‘kephalikos’). Veins form a complex network that allows all the tissues of the body to transport deoxygenated blood back to the heart. Lots … Read more

Decomposer Definition A decomposer is an organism that decomposes, or breaks down, organic material such as the remains of dead organisms. Decomposers include bacteria and fungi. These organisms carry out the process of decomposition, which all living organisms undergo after death. Decomposition is an important process because it allows organic material to be recycled in … Read more

Muscle Tissue Definition Animals have muscle tissue which functions by contracting, thereby applying forces to various parts of the body. Fibers of muscle cells are connected in sheets and fibers to form muscle tissue.  Combined, these sheets and fibers form muscles, which control an organism’s movements, as well as other contractile functions. An animal’s muscles … Read more

Homeostasis Definition Homeostasis is an organism’s process of maintaining a stable internal environment suitable for sustaining life. The word homeostasis derives from Greek, with home meaning “similar,” and stasis, meaning “stable.” When used as an adjective, it is homeostatic. We normally think about homeostasis in terms of the whole body, but individual systems – that … Read more

Definition The deltoid muscle is a tripartite muscle mass that connects the humerus bone of the arm to the scapula and clavicle bones. When you raise your arms above your head, the deltoid muscle is at work. This muscle, also known as the common shoulder muscle, is seen in many different vertebrate species! Overview The … Read more