Chapter 10 - Senses Flashcards
general senses
The senses which are perceived due to receptors scattered throughout the body such as touch, temperature, and hunger, rather than tied to a specific structure, as the special senses vision or hearing are. Often, the general senses are associated with a specific drive; that is, the sensation will cause a change in behavior meant to reduce the sensation.
special senses
the senses that have specialized organs devoted to them, such as vision (the eye) and smell (the nose)
encapsulated receptor cell
a receptor cell that is covered by a capsule of some sort
unencapsulated receptor cell
a receptor cell that is not covered by a capsule
photoreceptors
receptor cells that are sensitive to change in intensity or color of light, as in vision
chemoreceptors
receptor cells that are sensitive to presence of certain chemicals, as in taste or smell
pain receptors
receptor cells that are sensitive to physical injury
thermoreceptors
receptor cells that are sensitive to changes in temperature
mechanoreceptors
receptor cells that are sensitive to mechanical stimuli that change their position or shape
receptor cell
a cell or group of cells that receives stimuli
rods and cones (eye)
Cones and rods are two types of photoreceptors within the retina. This means that they are responsible for receiving signals (or images), processing them, and sending them to the brain.
Rods work at very low levels of light. We use these for night vision because only a few bits of light (photons) can activate a rod. Rods don’t help with color vision, which is why at night, we see everything in a gray scale. The human eye has over 100 million rod cells.
Cones require a lot more light and they are used to see color. We have three types of cones: blue, green, and red. The human eye only has about 6 million cones. Many of these are packed into the fovea.
Organ of Corti
an organ of the inner ear located within the cochlea which contributes to audition (hearing)
crista ampullaris
also spelled cristae ampullares; they are the sensory organ of rotation. They are found in the ampullae of each of the semicircular canals of the inner ear, meaning that there are 3 pairs in total. The function of the crista ampullaris is to sense angular acceleration and deceleration.
macula (macula lutea)
an oval-shaped pigmented area near the center of the retina of the human eye and in other animals
The macula is responsible for the central, high-resolution, color vision that is possible in good light; and this kind of vision is impaired if the macula is damaged, for example in macular degeneration.
retina
the sensory membrane that lines the eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve
fovea (fovea centralis)
a small pit in the back of the eye that helps with the sharpness or detail of images
lens (eye)
also called the crystalline lens; it is an important part of the eye’s anatomy that allows the eye to focus on objects at varying distances. It is located behind the iris and in front of the vitreous body.
optic nerve
The nerve that carries messages from the retina to the brain.
iris
The colored tissue at the front of the eye that contains the pupil in the center. The iris helps control the size of the pupil to let more or less light into the eye.
vitreous body
also called vitreous humour; the clear colorless transparent jelly that fills the eyeball posterior to the lens and is enclosed by a delicate hyaloid membrane
hyaloid membrane
also called the the vitreous membrane or vitreous cortex; it is a layer of collagen separating the vitreous humour from the rest of the eye. At least two parts have been identified anatomically:
The posterior hyaloid membrane separates the rear of the vitreous from the retina. It is a false anatomical membrane. The anterior hyaloid membrane separates the front of the vitreous from the lens.
pupil (eye)
the circular black area in the center of an eye, through which light enters
ampullae
a dilated portion of a canal or duct, especially of the semicircular canals of the ear.
cochlea
a hollow tube in the inner ear of higher vertebrates that is usually coiled like a snail shell and contains the sensory organ of hearing
proprioceptors
a sensory receptor (such as a muscle spindle) excited by proprioceptive stimuli (such as changes in limb position)
proprioception
also referred to as kinaesthesia (or kinesthesia), it is the sense of self-movement and body position. It is sometimes described as the “sixth sense”.
referred pain
pain that is perceived at a location other than the site of the painful stimulus/origin. It is the result of a network of interconnecting sensory nerves, that supplies many different tissues
cornea
The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.
sclera
The white layer of the eye that covers most of the outside of the eyeball. It is fibrous and provides support for the eyeball, helping it keep its shape.
choroid
A thin layer of tissue that is part of the middle layer of the wall of the eye, between the sclera (white outer layer of the eye) and the retina (the inner layer of nerve tissue at the back of the eye). It is filled with blood vessels that bring oxygen and nutrients to the eye.
Ciliary muscle
A circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing.