1.2 Stimuli and Responses in Humans Flashcards
What is the sclera?
A hard & firm white layer
Protects the eyes and maintains eye shape
What is the primary function of the cornea?
Helps focus light on the retina
It is the front part of the sclera, and it is transparent
What is the choroid?
The middle layer of the eye wall that is dark in color
Prevents light reflection in the eye and is rich in blood vessels
What function does the iris perform?
Controls the size of the pupil
The choroid layer surrounds the pupil
What is the pupil?
The opening in front of the eyes
Allows light to enter the eyes
What are the characteristics of the lens?
Elastic & translucent bioconvex lenses
Refracts and focuses light rays onto the retina
What is the function of the ciliary muscle?
Changes the thickness of the lens to help the eye focus on things at different distances, which is a process called accomodation
Projection muscles of the choroid
What does the suspensory ligament do?
Holds the pupil in place
Connects the ciliary muscles with the lens of the eye
What are vitreous humor and aqueous humor?
Translucent liquids that fill the eye space
Maintain eye shape and help focus light rays on the retina
What is the primary function of the retina?
Detects light stimuli
Contains layers with light-sensitive cells
What is the optic nerve?
The nerves that connect the retina to the brain
Sends impulses from the retina to the brain
What is the fovea?
A small dent in the retina, also known as the yellow spot
Detects light & produces nerve impulses; the most sensitive place on the retina
What is the blind spot?
Part of the retina that has no photoreceptors, and isn’t sensitive to light
Exit point for optic nerves
What is the function of the conjunctiva?
To protect the front part of the sclera
Transparent membrane
What are sensory organs?
Organs that can detect stimuli
Sensory organs play a crucial role in how organisms perceive their environment.
How many sensory organs do humans have?
Five
The five sensory organs are skin, nose, tongue, ears, and eyes.
What is the sensory organ responsible for touch?
Skin
Skin contains receptors that respond to various types of physical stimuli.
What is the sensory organ responsible for smell?
Nose
The nose contains olfactory receptors that detect airborne chemicals.
What is the sensory organ responsible for taste?
Tongue
The tongue has taste buds that respond to different flavors.
What is the sensory organ responsible for hearing?
Ears
Ears detect sound waves and convert them into signals for the brain.
What is the sensory organ responsible for sight?
Eyes
Eyes detect light and allow organisms to perceive visual information.
What is one function of the eyes?
Focusing on objects near and far
This ability to focus is essential for clear vision at different distances.
What do the eyes produce that is sent directly to the brain?
Continuous images
The brain processes these images to create a coherent visual experience.
True or False: The eyes only function to focus on nearby objects.
False
Eyes can focus on both near and far objects.
What enters the eye through the pupil?
Light from an object
What refracts light in the eye?
Cornea, aqueous humor, eye lens, and vitreous humor
What kind of images are formed on the retina?
Inverted and small images
What does the retina produce?
Nerve impulses
What transmits nerve impulses from the retina to the brain?
Optic nerve
What does the brain do with the nerve impulses?
Translates impulses and produces upright images
What are the functions of ears?
To keep our balance and hearing
True or False: The ears also function as a sense of smell.
False
What is the function of the ossicles?
Amplifies the vibration of sound and sends it to the oval window
The ossicles are tiny bones located in the middle ear that play a crucial role in hearing.
What does the earlobe do?
Receives sound waves
The earlobe is the external part of the ear that helps capture sound.
What is the role of the ear canal?
Transmits sound waves to the eardrum
The ear canal is a tube that directs sound to the eardrum.
What happens to the eardrum when sound waves hit it?
Vibrates when sound waves hit it
The eardrum is a membrane that responds to sound by vibrating.
What is the function of the semicircular canal?
Controls body balance
The semicircular canals are part of the inner ear and are essential for maintaining balance.
What does the auditory nerve do?
Sends impulses from the cochlea to the brain
The auditory nerve transmits sound information to the brain for processing.
What is the role of the cochlea?
Converts sound vibrations into impulses
The cochlea is a spiral-shaped organ in the inner ear involved in hearing.
What does the oval window do?
Transmits sound vibrations from the middle ear to the inner ear
The oval window is a membrane-covered opening that connects the middle ear to the inner ear.
What is the function of the Eustachian tube?
Balances the air pressure on both sides of the eardrum
The Eustachian tube connects the middle ear to the throat and helps equalize pressure.
What is the first step in the mechanism of hearing?
Sound waves enter the ear canal
This initiates the process of hearing.
What happens to sound waves when they reach the eardrum?
The eardrum receives sound waves and vibrates
This vibration is crucial for further amplification.
What role do the ossicle bones play in hearing?
The vibrations are amplified by the ossicle bone and transmitted to the oval window
The ossicles consist of three small bones: malleus, incus, and stapes.
What occurs at the oval window during the hearing process?
The oval window vibrates
This is a critical step that leads to the conversion of mechanical vibrations into neural signals.
How does the cochlea contribute to hearing?
The cochlea converts vibrations into impulses
The cochlea is a fluid-filled structure in the inner ear.
What carries the auditory impulses to the brain?
Impulses are carried by the auditory nerve to the brain
The auditory nerve is essential for transmitting sound information.
How does the brain interpret sound?
The brain interprets it as sound
This interpretation allows us to recognize and understand what we hear.
What is one function of the nose?
Provides air for breathing
This is a primary function essential for life.
What does the nose do during respiration?
Filters and cleans foreign debris during respiration
This helps maintain respiratory health.
What is the sense associated with the nose?
As a sense of smell
The olfactory receptors in the nose are responsible for detecting odors.
Fill in the blank: The _______ converts vibrations into impulses.
cochlea
The cochlea plays a vital role in the auditory system.
What is a cilium?
A tiny, hair-like structure found on the surface of certain cells.
What does the cilium contain to assist in olfaction?
Mucus to dissolve the particles inhaled during respiration.
What do receptor cells in the olfactory system do?
Detect odors and generate nerve impulses.
What is the role of nerves in the olfactory system?
Send nerve impulses to the brain to be interpreted.
Where are the sensory cells for smell located?
At the roof of the nasal cavity.
What happens to air when it is inhaled through the nostrils?
Air is sucked in and goes through the nasal cavity.
What is the final destination of nerve impulses generated by the olfactory system?
The brain for processing.
Fill in the blank: The cilium contains _______ to dissolve the particles inhaled during respiration.
mucus
What are the functions of the tongue?
- Helps with the movement of food during chewing and swallowing (digestive function).
- Acts as a sense of taste.
What are the main sensory receptors in the skin?
Pain receptors, pressure receptors, touch receptors, heat receptors, and cold receptors.
What covers the surface of the tongue?
Taste buds containing many taste receptors scattered across the tongue.
How do taste receptors work?
They are sensitive to chemicals in food, allowing us to perceive different tastes.
What are the functions of the skin?
- Protects us from microbes.
- Allows sensations of touch, temperature, and pressure.
- Acts as a sense of touch.
What are the five types of taste receptors on the tongue?
Sweet, sour, salty, bitter, and umami (savory).
What are the three main layers of the skin?
- Epidermis – Protective outer layer.
- Dermis – Contains nerve endings, blood vessels, and glands.
- Hypodermis – Fat and connective tissue for insulation and cushioning.
What is the function of pain receptors?
They detect and respond to harmful stimuli, warning the body of injury.
What do pressure receptors in the skin detect?
They sense deep pressure and vibrations on the skin.
What is the role of touch receptors?
They detect light touch and texture changes on the skin’s surface.
What do heat receptors do?
They sense temperature increases, helping detect warmth.
What is the function of cold receptors?
They respond to temperature decreases and detect cold sensations.
What structures are also present in the skin aside from sensory receptors?
Hair and sweat holes (sweat glands).
What determines skin sensitivity?
The number of receptors present and the thickness of the epidermis.
How do receptors affect skin sensitivity?
More receptors = higher sensitivity.
How does epidermis thickness affect sensitivity?
Thinner epidermis = higher sensitivity.
Why can blind people read Braille with their fingertips?
Fingertips have a high concentration of touch receptors, making them very sensitive.
What are very sensitive parts of the skin?
Fingertips, back of the neck, lips, and earlobes.
What are less sensitive parts of the skin?
Elbows and knees.
How are sensory organs interconnected?
They work together to maintain balance and process stimuli daily.
What is the limit of sensory ability?
The point beyond which our senses cannot detect a stimulus.
What causes sensory limitations?
Sensory organ defects or the aging process.
What is the visual sensory limitation of the eye?
The eye cannot detect an image that falls on the blind spot.
Q: What are common vision problems?
Farsightedness, nearsightedness, astigmatism, and presbyopia.
What affects human vision?
Eye structure differences causing focusing issues.
What is the normal vision structure?
The eye focuses light directly onto the retina, creating a clear image.
What is short-sightedness (myopia)?
A condition where the eye focuses light in front of the retina, making distant objects appear blurry.
What causes myopia?
An elongated eyeball or overly curved cornea, causing improper light focus.
What is long-sightedness (hyperopia/hypermetropia)?
A condition where the eye focuses light behind the retina, making nearby objects appear blurry.
What causes hyperopia?
A shorter eyeball or a flatter cornea, leading to improper focus.
What is nearsightedness (myopia)?
A condition where distant objects appear blurry because light is focused in front of the retina.
What is farsightedness (hyperopia)?
A condition where close objects appear blurry because light is focused behind the retina.
What type of lens is used to correct nearsightedness (myopia)?
A concave lens helps spread out light before it enters the eye, allowing proper focus on the retina.
What type of lens is used to correct farsightedness (hyperopia)?
A convex lens helps converge light before it enters the eye, bringing it into focus on the retina.
What is normal vision?
Normal vision occurs when light is correctly focused on the retina, allowing clear vision
What is astigmatism?
Astigmatism is a vision condition where the cornea has an irregular shape, causing blurred or distorted vision.
How can astigmatism be corrected?
Astigmatism can be corrected using specially designed lenses that help focus light properly onto the retina.
Why do images appear blurred in astigmatism?
Images are blurred and unclear because light from objects is separated and focused at different points on the retina.
How can astigmatism be corrected?
Astigmatism can be corrected using a cylindrical lens or by undergoing surgery.
What is the function of a normal eye’s lens?
The lens of a normal eye focuses light directly onto the retina for clear vision.
What is presbyopia?
Presbyopia is an age-related condition where the lens becomes less flexible, making it difficult to focus on nearby objects.
How can presbyopia be corrected?
It can be corrected using reading glasses, bifocals, or multifocal lenses.
Why do elderly people have trouble seeing both near and distant objects?
Aging causes the lens to lose flexibility, leading to difficulty focusing on both near and distant objects, a condition called presbyopia.
What type of lens is needed for presbyopia?
A dual-focus lens (bifocal or progressive lenses) helps in seeing both near and far objects clearly.
What are some technologies used to enhance vision?
Magnifying glass & microscope: Helps see small objects.
Binoculars & telescopes: Helps see distant objects.
What is the normal hearing range for humans?
Humans can hear sounds between 20Hz to 20,000Hz.
What causes deafness?
Deafness can be caused by:
- Ossicle bones fusing together due to infection.
- Aging leading to natural hearing loss.
- Prolonged exposure to loud noise damaging the inner ear.
How can deafness be treated?
Deafness can be managed with:
- Hearing aids to amplify sound.
- Surgery, such as cochlear implants, to restore hearing.
What technologies help enhance hearing?
- Stethoscope: Amplifies the heartbeat.
- Loudspeaker: Amplifies sound for better hearing.
