Search
-
- Glossary
Gene
Information unit on DNA. Specialized enzymes translate the core component of a gene into ribonucleic acid (RNA). While some ribonucleic acids perform important functions in the cell themselves, others specify the order in which the cell should assemble individual amino acids into a specific protein. The gene thus provides the code for this protein. In addition, a gene also includes regulatory elements on the DNA that ensure that the gene is read exactly when the cell or organism actually needs its product.
-
- Glossary
Olfactory epithelium
An area of olfactory cells measuring approximately 5 cm² located at the rear of the nasal septum. The axons (long, fiber-like extensions of nerve cells) of the olfactory cells form the olfactory nerve and travel through the ethmoid bone to the olfactory bulb.
-
- Glossary
Taste
The sensory impression we refer to as "taste" results from the interaction between our senses of smell and taste. In terms of sensory physiology, however, "taste" is limited to the impression conveyed to us by the taste receptors on the tongue and in the surrounding mucous membranes. It is currently assumed that there are five different types of taste receptors that specialize in the taste qualities sweet, sour, salty, bitter, and umami. In 2005, scientists also identified possible taste receptors for fat, whose role as a distinct taste quality is still being investigated.
-
- Glossary
Taste bud
Taste buds are groups of taste cells in the oral mucosa and are therefore the site of taste perception.
-
- Glossary
Taste papilla
Taste papilla are specific surface structures on the tongue that contain taste receptors. They are distinguished by their size, shape, and density of taste receptors. There are wall, leaf, mushroom, filament, and lentil papillae.
-
- Glossary
Field of view
The area of the outside world that can be perceived when the head is held still and the gaze is straight ahead. In humans, it is approximately 180° horizontally, of which about 120°–140° is binocular; vertically, it is approximately 135°. Rabbits achieve 360° thanks to their sideways-facing eyes, although their binocular field of vision – i.e., the intersection of both eyes – only covers 30°.
-
- Glossary
Gesture
A nonverbal form of communication in which certain movements convey meaning – a shrug of the shoulders, a dismissive wave of the arm.
-
- Glossary
Vitreous body
The vitreous body consists of a gel-like substance inside the eye that supports the shape of the eye.
-
- Glossary
Glial cells
Glia cells are the second largest group of cells in the brain after neurons. For a long time, they were considered inactive elements of the brain, referred to as "nerve cement." Today, we know that the different types of glia cells (astrocytes, oligodendrocytes, and microglia in the CNS; Schwann cells in the PNS) perform clearly defined tasks in the nervous system. For example, they respond to pathogens, play an important role in nourishing nerve cells, and insulate nerve fibers. They account for slightly more than 50 percent of the brain's cells, compared to neurons.
-
- Glossary
Gliotransmitter
Chemical messengers released by astrocytes and other glial cells. They enable glial cells to communicate with other cells in the nervous system, for example when forming a synapse. The most common types of gliotransmitters are the amino acids glutamate and D-serine, as well as adenosine triphosphate (ATP).
