2.1.2 Sensory receptors Flashcards
(17 cards)
What is a sensory receptor?
A sensory receptor is a structure that detects a stimulus and converts it into an action potential or nerve impulse.
A stimulus is a physical or chemical change in the environment.
What are the different types of sensory receptors?
- Chemoreceptor
- Thermoreceptor
- Mechanoreceptor
- Photoreceptor
- Nociceptor
These receptors are specific for different types of stimuli.
What do chemoreceptors detect?
Chemoreceptors detect the presence of chemicals by changing shape when they come into contact with specific molecules.
They are involved in the senses of smell and taste.
How do chemoreceptors function in smell?
Distance chemoreceptors in the nasal cavity detect airborne molecules.
This detection is essential for the sense of smell.
How do chemoreceptors function in taste?
Direct chemoreceptors on the tongue are stimulated by specific chemicals in food and drink.
Different tastes correspond to different chemical compounds.
What are the types of taste detected by chemoreceptors?
- Sour - acidic H+
- Salty - K+, Ca2+, Na+
- Sweet - sugars & alcohols (-OH)
- Bitter - alkaloids
- Umami - MSG
These categories represent the primary taste sensations.
What do photoreceptors transform?
Photoreceptors transform light energy into electrochemical energy interpreted by the brain as visual images.
This process is essential for vision.
What are the two types of photoreceptors and their functions?
- Rods - sensitive to light intensity (detect black or white)
- Cones - sensitive to particular wavelengths (perception of color)
Cones include three types: blue, green, and red.
What do thermoreceptors detect?
Thermoreceptors detect changes in body temperatures.
They are involved in thermoregulation.
What are the two types of thermoreceptors in endotherms?
- Heat Receptors - respond to warmer temperatures
- Cold Receptors - respond to colder temperatures
Each type has specific temperature ranges for sensitivity.
What is the temperature range for heat receptors?
Most sensitive between 25°C and 55°C.
Temperatures above 55°C stimulate pain receptors.
What is the temperature range for cold receptors?
Most sensitive between 10°C and 20°C.
Temperatures below 10°C stimulate pain receptors.
What do mechanoreceptors respond to?
Mechanoreceptors respond to mechanical forces such as pressure or distortion.
They are important for hearing, touch, and pain.
Where are mechanoreceptors found in the ear?
- Tiny hairs in the semicircular canals (balance)
- Tiny hairs in the cochlea (sound vibrations)
These structures help with auditory and balance functions.
What do nociceptors respond to?
Nociceptors respond to noxious stimuli, such as extremes in temperature, pressure, or noxious chemicals.
They are responsible for the perception of pain.
What is the function of nociceptors?
They send signals to the spinal cord and brain that result in the perception of pain.
They are located throughout the body.
What is the homeostatic response to tissue injury?
It involves a complex series of both positive and negative feedback loops during the initial response and healing process.
This response is critical for recovery and maintaining homeostasis.
