Lesson 10: Organisms Sense Their Environment

Sensory Receptors

Detect information from inside (enteroreceptors) and outside (exteroreceptors) the body.

Mechanoreceptors

Detect mechanical forces; associated with touch, hearing, and balance.

Chemoreceptors

Detect chemical stimuli, notably for taste (gustation) and smell (olfaction).

Photoreceptors

Detect light (photons); found in the eyes.

Thermoreceptors

Respond to temperature changes.

Nociceptors

Detect potential tissue damage, initiating pain sensation.

Steps of Conveying Sensory Information

1. Stimulation, 2. Transduction, 3. Transmission, 4. Interpretation.

Baroreceptors

Detect blood pressure changes and send action potentials to the spinal cord when pressure increases.

Taste Buds

Located on the tongue and oral cavity, involved in detecting sweet, salty, bitter, sour, and umami flavors.

Cochlea

Fluid-filled structure in the ear; hair cells within detect sound frequencies.

Stimulation

The appropriate stimulus activates the receptor

Transduction

Stimulus energy is converted into receptor potential in sensory neurons

Transmission

If graded potentials reach threshold, action potentials are generated along the sensory neuron’s axon

Interpretation

The brain processes and assigns meaning to sensory information received from sensory neurons.

Vestibular Apparatus

Detects motion, acceleration, and gravity; contains hair cells

Proprioceptors

Provide info about body part positioning, in muscles and tendons