Human Phys Chapter 7

Sensation

The process of detecting physical stimuli from the environment through specialized sensory receptors such as those for touch, sound, light, and taste.

Perception

The brain's interpretation of the sensory signals it receives, allowing individuals to understand and make sense of their surroundings.

Mechanoreceptors

Sensory receptors that respond to mechanical forces, enabling the sensation of touch, pressure, vibration, and stretch in various parts of the body.

Thermoreceptors

Sensory receptors that respond to changes in temperature, allowing the body to perceive sensations of heat and cold.

Photoreceptors

Specialized sensory receptors in the retina of the eye that detect light, playing a crucial role in the sense of vision.

Chemoreceptors

Sensory receptors that respond to chemical stimuli, facilitating senses such as taste (gustation) and smell (olfaction).

Nociceptors

Sensory receptors that detect potentially harmful stimuli, signaling sensations of pain to warn the organism of injury or danger.

Sensory Transduction

The conversion of a physical stimulus (e.g., light, sound, or pressure) into an electrical signal within a sensory receptor, enabling neural processing.

Receptor Potential

The graded change in the membrane potential of a sensory receptor in response to a stimulus, influencing the likelihood of generating an action potential.

Somatic Senses

The group of senses that include the perception of touch, pain, temperature, and proprioception (the sense of body position and movement), providing information about the body's state.

Special Senses

The senses that have specialized organs dedicated to specific functions, including vision, hearing, taste, smell, and equilibrium (balance), enabling complex sensory experiences.

Cerebral Cortex

The outer layer of the brain where sensory information is processed, consisting of receiving areas for sensory input and association areas that interpret this information.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors (rods and cones) responsible for converting light into neural signals for vision.

Cornea

The transparent front part of the eye that refracts (bends) light rays to help focus them onto the retina, playing a critical role in vision.

Lens

A flexible, transparent structure in the eye that adjusts its shape to focus light rays precisely onto the retina, enabling clear vision at various distances.

Photopigments

Light-absorbing molecules located in the photoreceptor cells (rods and cones) of the retina, crucial for initiating the process of phototransduction and enabling vision.

Binocular Vision

A visual perception system that utilizes input from both eyes, allowing for depth perception and a three-dimensional view of the environment.

Visual Pathway

The neural path that visual information follows from the retinal ganglion cells through the optic nerve, optic chiasm, and thalamus, ultimately reaching the visual cortex for processing.

Retinal ganglion cells → Optic nerve → Optic chiasm → Optic tracts → Thalamus → Visual cortex

External Auditory Canal

The tube that channels sound waves from the outer ear to the tympanic membrane (eardrum), playing a crucial role in the hearing process.

Tympanic Membrane (Eardrum)

A thin membrane that vibrates when sound waves hit it, converting sound energy into mechanical vibrations for further processing in the ear.

Auditory Ossicles

Three small bones in the middle ear (malleus, incus, and stapes) that amplify and transmit vibrations from the tympanic membrane to the inner ear.

Oval Window

A membrane located between the middle ear and the cochlea that transmits sound vibrations from the auditory ossicles into the inner ear, initiating the process of hearing.

Cochlea

A spiral-shaped structure in the inner ear that converts sound vibrations into neural signals via hair cells, playing a key role in hearing.

Hair Cells

Specialized sensory cells located in the cochlea that detect sound vibrations and convert them into electrical signals, crucial for auditory perception.

Stereocilia

Tiny hair-like projections on hair cells in the cochlea that bend in response to sound vibrations, leading to changes in the electrical signals sent to the brain.

Auditory Pathway

The sequence of neural connections that sound information travels through from the cochlea (where it is transformed into neural signals) to the auditory cortex in the brain for interpretation. Cochlea → Auditory nerve → Brainstem → Thalamus → Auditory cortex