Senses Flashcards
What is the nervous system responsible for?
The nervous system is responsible for receiving and sending messages in the body in the form of electrical impulses.
What is the function of sensory and motor neurons?
• Sensory neurons: Carry impulses to the central nervous system (CNS).
• Motor neurons: Carry impulses away from the brain to muscles and glands.
What are sensory organs, and how do they work?
Sensory organs receive sensory information (stimuli) and send it to the CNS through sensory neurons.
What is a stimulus and a receptor?
• Stimulus: A change in the environment, such as light or sound.
• Receptor: A cell that detects a stimulus.
Match the sense with its receptor type.
• Sight: Photoreceptors.
• Hearing: Mechanoreceptors.
• Touch: Thermo- and proprioceptors.
• Taste: Chemoreceptors.
• Smell: Chemoreceptors.
What is the function of the eyelids, eyelashes, and eyebrows?
• Eyelids: Protect the eyes.
• Eyelashes: Trap dirt and dust.
• Eyebrows: Stop sweat from entering the eyes.
What is the function of the conjunctiva?
The conjunctiva is a thin, transparent lining that protects the cornea. Inflammation of the conjunctiva is called conjunctivitis.
Describe the structure and function of the cornea.
• Structure: Transparent front part of the sclera.
• Function: Focuses light rays on the lens and protection
What is the sclera, and what is its role?
The sclera is the tough, fibrous outer layer of the eye, known as the “white” of the eye. It maintains the shape of the eyeball and protection
What is the function of the choroid layer?
• Supplies food and oxygen to eye cells via blood vessels.
• Contains melanin to absorb light and prevent internal reflection.
What are the functions of the iris and pupil?
• Iris: Controls the amount of light entering the eye by changing the size of the pupil; also gives the eye its color.
• Pupil: The opening in the iris that allows light into the eye.
What is the retina, and what are its two types of receptor cells?
• Retina: The innermost layer of the eye that detects light.
• Receptor cells:
• Rods: Detect black and white; work in dim light; contain rhodopsin.
• Cones: Detect color; work in bright light; concentrated at the fovea.
What is the difference between the fovea and the blind spot?
• Fovea: A region on the retina with mostly cones for sharp vision.
• Blind spot: Where the optic nerve exits the retina; no receptors, so no vision occurs here.
What is the function of the optic nerve?
The optic nerve carries information from the eye’s receptors to the brain using sensory neurons.
What is the role of the lens and ciliary body in vision?
• Lens: A transparent, elastic structure that focuses light rays on the retina.
• Ciliary body/muscle: Changes the lens shape for focusing (accommodation).
