Sensory system Flashcards
Sensory System
Without sensory system, it would be impossible to know about your surroundings. Sensory perceptions involve seeing, hearing, tasting, smelling, and touching. Humans also receive impressions of warmth, softness, pressure, vibration, and pain through the sensory system.
Equilibrium is also important with sensing the body’s posture and position in space.
Functions
Visual Hearing Balance Equilibrium Taste Smell Touch Pain Pressure Vibration
Functions (More in Depth)
Functions of the sensory system: functions include visual, hearing, balance, equilibrium, taste, smell, touch, pain, pressure, vibration, and the brain interprets most of the sensations. General sense organs include muscles, tendons, joints, and internal organs. They detect stimuli such as pain, touch, temperature, pressure, itching, and proprioception (your physical spatial awareness). Special sensory organs are the eyes, ears, tongue, nose, and skin. These organs have a specialized function such as eyes for vision, ears for hearing, tongue for taste, nose for smell, and skin for touch. Sensory structures must be able to detect a stimulus or change in stimulus. The stimulus is then transformed into an electrical signal and transmitted to the brain or spinal cord.
Structures of the sensory system
Eye
-Sclera and cornea
-Iris and pupil
-Lens
-Retina
Ear
-External, middle and internal
Taste
SmellEye
the organ of vision. Lies in a ball-shaped cavity of the skull called the orbit. The study of the eye and vision is ophthalmology. Tears in the eye contain an enzyme that help protect the eyes from bacterial infection. Lacrimal glands produce tears. Vision depends on the size of the object, brightness, contrast between object and the background, and speed or time allowed to see the object.
Eyeball: hollow sphere about 1 in in diameter.
Sclera and cornea
sclera is the protective outer layer of the eye known as the “white of the eye.” The sclera helps maintain the eyes shape. The cornea influences visual acuity by refracting light rays.
Iris and pupil
Iris gives the eye its specific color and smooth and smooth and radial muscles in the iris control the size of the pupillary opening. Pupil is the black center opening within the eye that allows light to enter. In bright light, muscles constrict the pupil. In low light the pupils dilate.
Lens
located behind the pupil and iris the major role is focusing light rays into the retina.
Retina
eyeballs inner layer, a light sensitive membrane. Contains specialized neurons, rods, and cones. Rods receive sensations of black and white and register shapes. Rods are useful for night vision. Color vision depends on cones and receive red, blue, or green light.
Ear
organ of hearing (auditory sense) and equilibrium (proprioception). Divided into external, middle, and inner ear. The study of ear disorders is otology, and hearing and measurement of hearing is known as audiology. Sound is energy that moves in waves of pressure. The perception of sound is known as audition. The tympanic membrane vibrates at various speeds in response to various pitches in sound.
External ear
the pinna or auricle is the only readily visible part of the ear. Composed mostly of cartilage and is funnel shaped which assists in gathering soundwaves into a small opening. Cerumen or ear wax and hairs protect the auditory canal from foreign substances. The tympanic membrane separates the external ear from the middle ear.
Middle ear:
begins after the tympanic membrane. The middle ear is an air filled cavity in the temporal bone. The malleus (hammer), incus (anvil), and stapes (stirrup) bones are located in the cavity. The stapes transmits sound vibrations to the inner ear. The three bones are known as ossicles, which are so small that sound waves can set them into motion.
Inner ear
embedded in the temporal bone, which is the densest bone in the body. Soundwave transmission is conducted through the inner ear. Inner ear is divided into the cochlea, vestibule, and semicircular canals. The cochlea is shaped like a hollow snail shell. Known as the “true organ of hearing” as transmission of nerve stimuli related to hearing occurs in the structure. The Vestibule sends sensory information to the cerebellum and midbrain which relay changes of body position (static balance) via specialized hair cells. The semicircular canals are shaped like horseshoes and primarily concerned with balance when the body is moving.
Taste
sense of taste (gustation) is based on perceptions of sweet, salty, sour, bitter, metallic, fatty or meaty and their combinations. Tastes buds are located in the mouth and detect chemicals in solutions in the mouth. Basic tastes are perceived by taste buds on the tongue, lining of the cheek, and roof of the mouth. Many tastes are influenced by the sense of smell.
Smell
the sense of smell (olfaction) is the result of chemical molecules entering the nose and rise in the upper nasal cavity to the sensory area. Specific receptors for different odors interact in fashion with the nerves. In order for odors to be detected, chemicals must be dissolved in the watery mucus lining of the nasal cavity
