Chapter 36Sensory

Reception

Sensory Receptors

• Mechanoreceptors– Pressure, position, and

acceleration

• Thermoreceptors– Heat

• Pain Receptors (Nociceptors)

– Pain and tissue damage

• Chemoreceptors– Chemical and pH

changes in fluids • Osmoreceptors

– Water volume

• Photoreceptors– Visible and UV light

Sensory Pathways

• Receptor endings of a sensory neuron are stimulated by stepping on a tack

Sensory Adaptation

• Increase in frequency corresponds to increases in strength of stimulus

The effects of increases in stimulus strength

Receptors Near the Body Surface

• Receptors in human skin

I. Sense of Taste–Chemoreceptor–4 Sensations

•Sweet, sour, salty, bitter

II. Sense of Smell

• Olfactory– Gases – Pheromones

Try this one

Ok one more

III. Components of the Human Ear

• External• Middle

– Stirrup– Anvil– Hammer

• Inner– Cochlea

A. Sense of Balance

Location of Internal Ear in Human

Sense of Balance

• Inner ear– Equilibrium– Fluid-filled sacs

• Vestibular apparatus– Hair cells– Otoliths– Linear Motion

• Semicircular canals– Rotational motion– Acceleration

Inside a Human Ear

Sense of Balance

B. Sense of Hearing

• Perception of Sounds

• Wavelength• Amplitude• Frequency

Sensory Reception in the Human Ear

• Cochlea– Acoustical

receptors– Hair cells

• Sound reception

C. Origin of Corti• Basilar membrane• Scala vestibuli• Scala tympani

• Another one?• Last one

IV. Sense of Vision

A. Eyes– Photoreceptors

• Pigments– Simple Eyes

B. Complex Eyes

• Developed eye– Lens– Cornea– Compound

• Photoreceptor

1. Structure and Function of Vertebrate Eyes

• Outer layer– Sclera & Cornea

• Middle layer– Choroid– Ciliary body– Iris & Pupil

• Inner layer– Retina– Lens– Vitreous body

2. Pattern of Retinal Stimulation

• Pattern– Upside-down and reversed left to right

3. Focusing MechanismsVisual Accommodation

• Ciliary Muscle

Far objects

Near objects

4. Organization of the Retina

Organization of the Retina• Rods

– Detect dim light– Rhodopsin

• Absorbs blue-to-green

• Cones– Detect bright light– Red, green, and blue

• Each with different pigment

Organization of Retina• Visual information

flows from photoreceptors to:

– Bipolar sensory neurons

– Ganglion cells– Horizontal cells – Amacrine cells

5. On to the Visual Cortex

• Right side of retina– Intercepts light from left half of visual field

• Left side of retina – Intercepts light from right half of visual field

• Optic Nerve - Signals from right visual field to left hemisphere, from left visual field to right hemisphere

On to the Visual Cortex

Disorders of the Human Eye

• Nearsighted vision– Focal point in in front of retina

Disorders of the Human Eye

• Farsighted Vision– Focal point occurs behind the retina