Overview of Animal Sensory Systems and Mechanisms (3)

Sensory receptors

Cells responding to specific stimuli, transmitting signals.

Thermoreceptors

Sense heat and cold temperatures.

Electromagnetic receptors

Detect light and electromagnetic fields.

Mechanoreceptors

Detect sound, touch, and motion. Hair cells

Pain receptors

free nerve endings transmit ___ in response to thermal and mechanical stimuli or molecules released by injured cells

Vibrations from sounds

transmitted from the tympanic membrane through the three middle ear bones to the cochlea

Volume and pitch

detected by the number of hair cells stimulated

the position of the stimulated cells along the cochlea

Lateral line

system of aquatic vertebrates that is used to detect vibrations and currents in water

Chemoreceptors

Detect solutes, tastes, and smells.

Oldest and most universal sense

Important in identifying food, mates, predators, noxious chemicals, CO2, H2O

Olfactory cells

chemoreceptors providing a sense of smell. Detect signals that are far, and at low threshold

Pheromones

chemicals used for communication among same species

Vomeronasal organ

in the roof of the mouth of some vertebrates for chemoreception, in response to pheromones

Flehmen response

the pulling back of the lips draw molecules towards the organ increasing effectiveness

Electroreception

detect the electric field produced by the muscle activity of living organisms. Well developed in sharks and for prey detection. Platypus has them on their bills

Gustation cells

the receptors of taste

in humans, receptor cells for taste are organized as taste buds

Afferent neuron

Transmits sensory information to the CNS.

Motor commands

Signals sent from CNS to muscles or glands.

Neuronal receptors

Afferent neurons acting as sensory receptors.

Non-neuronal receptors

Regulate afferent neurons without direct transmission.

Free nerve endings

Transmit pain signals from thermal and mechanical stimuli.

Hair cells

Mechanoreceptors for hearing and equilibrium.

Cochlea

Inner ear structure for sound processing.

Basilar membrane

Vibrates in response to sound frequencies.

Tectorial membrane

Interacts with hair cells in the cochlea.

Olfaction

Sense of smell via olfactory cells.

Gustation

Sense of taste through gustatory cells.

Papillae

Structures on the tongue housing taste buds.

Photoreceptors

Cells responding to light in the retina.

Rhodopsin

Pigment changing configuration in light response and trigger a reaction that stimulates nerves

Rod photoreceptors

are sensitive to low light

Cone photoreceptors

sensitive to specific frequencies of light

Single-lens eyes

Focus light on photoreceptors in the retina.

Statolith

Granules aiding balance in inner ear.

Action potentials

Electrical signals transmitting information along neurons.

Lateral inhibition

Neuronal interaction enhancing image contrast.

Pit organs

detect infrared radiation and function in thermal imaging