1. Senses Part 1

2. General and Special Senses
Types of General Senses:
Touch
Pain
Temperature
Vibration
Itch
Proprioception
Types of Special Senses:
Smell
Taste
Sight
Hearing
Balance

3. Sensory Receptors Mechanoreceptors: Respond to bending or stretching
Sensory Receptors: Are sensory nerve endings or specialized cells capable of responding to stimuli by developing action potentials.
Type of Receptors:
Mechanoreceptors: Respond to bending or stretching
Chemoreceptors: Respond to chemicals
Photoreceptors: Respond to light
Thermoreceptors: Respond to heat
Nociceptors: Respond to pain

4. Sensory Receptors in the Skin

5. Olfaction
Olfaction: Occurs in response to airborne molecules, called odorants, that enter the nasal cavity.
Olfactory neurons are bipolar neurons with in the olfactory epithelium.
There are 400+ functional olfactory receptors in humans
Olfactory receptors can bind to multiple olfactory receptors. Causing more combination of smells.

6. Neuronal Pathway for Olfaction
Bring odorants into nasal cavity
Axons from olfactory neurons form the olfactory nerves (1) Olfactory Nerve
These axons pass through the foramen of cribriform plate and enter the olfactory bulb
There they synapse with interneurons that send action potentials to the brain through olfactory tracts and travel to the olfactory cortex.

7. Taste The sensory structures that detect taste are called taste buds.
Taste buds are oval structure located on the papillae of the tongue.
Each taste bud contains about 40 taste cells
Taste HairsTaste Pores

8. Taste Sensations Taste sensations are divided into 5 basic types:
Bitter
Salty
Sweet
Umami
Sour
Taste is strongly influenced by olfaction

9. Neuron Pathway for Taste
Taste sensations are received by taste buds.
Taste sensations are carried by three Cranial Nerves
(VII) Facial Nerve
(IX) Glossopharyngeal Nerve
(X) Vagus Nerve
The message is then sent to to the Brain Stem to the thalamus to the parietal lobe of the brain’s (Taste Area)

10. Vision (Accessory Eye Structures)
Accessory Structures of the Eye:
Eyebrows: Protect the eyes by preventing perspiration from running down the forehead into the eye, and also provide shade from direct sunlight.
Eyelids: Protect the eyes from foreign objects and aid in lubrication.
Conjuctiva: Thin mucus layer
Lacrimal Apparatus: Produces tears that lubricate and cleanse the eye. Also drain excess fluid into the lacrimal duct.

11. Anatomy of the Eye Tunics of the eye: Fibrous Tunics Sclera Cornea
Vascular Tunics
Choroid
Iris
Ciliary Body
Nervous Tunic
Retina

12. Contraction of the Iris

13. Anatomy of the Eye Eye Structures: Lens: Flexible and Biconcave
Pupil: Hole that lets light pass through
Optic Nerve: Sends images to the brain
Retinal Blood Vessels:

14. Photoreceptors of the Retina
Rod: Detect Light (Dark and Light)
Cons: Detect Color
Red
Blue
Green