Reading Assignment: POHS Chapter 42: pp. 927 - 951

Self Quiz: 1-10

Applying Concepts: 1 - 2, 4 - 5

Additional Thought Question: Like terrestrial mammals, fish have olfactory organs. However, obligate marine mammals such as whales and dolphins do not. Why?

Lecture outline:

Definition of sensory system

General properties of sensory cells and organs
	transduction
	modalities
	sensors
	conscious and unconscious information
	processing of sensory information
		adaptation

Transduction
	direct
	indirect (secondary messenger)
	neuronal vs. non-neuronal sensors and the generation of the action potential (AP)

Information coding and the action potential (AP)
	frequency of Aps is proportional to intensity of stimulus 

Chemosensors

	Vertebrate olfaction - neurons as sensors
		structure
		signal transduction

	Vertebrate gustation - sensory organs
		structure of taste bud
		signal transduction
		diversity of taste buds

N.B. Grievous error in text (pp. 933-934): Tongue flicking in snakes and other squamates is associated with vomerolfaction (vomeronasal organ) and not olfaction (olfactory organ); these are two distinct sensory systems.

Mechanoreceptors

	Dermal receptors
		types and modalities

	Stretch receptors of the musculo-skeletal system

	Hair cells
		distribution 
		structure

	Vertebrate acousticovestibular organs
		vestibular organs
			semicircular canals
			macular organs (saccule, utricle)
		acoustic organ

	Mammalian auditory apparatus
		structure:
			external ear
			middle ear
			inner ear
				basilar membrane
				organ of Corti
				tectorial membrane
		signal transduction

Photosensors

	Rhodopsin

	Vertebrate rod cells
		structure
		signal transduction

	Vertebrate eye
		structure
			cornea
			iris and pupil
			lens
			accommodation
	
	Retina
		structure
			fovea
		rod cells
		cone cells and color vision
		ganglion cells
		other cell types

Other sensory systems

	ultraviolet (UV) vision
	infra-red radiation
	echolocation
	vomerolfaction

Topics not covered in lecture for which you will be responsible:

	arthropod chemoreception			pp. 931-932
	arthropod statocysts and statoliths		pp. 935-936
	conduction vs. nerve deafness			pp. 939-940
	invertebrate visual systems			pp. 942-943

Topics for which you will not be responsible:

	on / off receptive fields			pp. 947-948