ScribePost: April 7 (18.3 Sense of Taste and Smell)

Hi girls,

So we started class today reviewing the homework from last night.

Somatic sensors can be categorized into three types:

1. Proprioceptors - are involved in reflex actions that maintain muscle tone
2. Cutaneous - the skin is composed of 2 layers: the epidermis and the dermis. The epidermis is stratified squamous epithelium, and the dermis is a thick connective tissue layer. The dermis contains cutaneous receptors, which make the skin sensitive to touch, pressure, pain and temperature. The two different types of cutaneous receptors that are sensitive to pressure are Pacinian corpuscles and Ruffini endings.
3. Pain Receptors - the skin and many internal organs and tissues have pain receptors. Sometimes stimulation of internal pain receptors is felt as pain from the skin, and the internal organs, which is called referred pain.

We then moved onto learning about the sense of taste and smell (18.3)

Sense of Taste and Smell

• Taste cells and olfactory cells (smell) are both chemoreceptors

Sense of Taste

• The sensory receptors in your mouth are called taste buds
• There are approximately 10 000 taste buds on a human tongue
• Each papillae (the small elevations on the tongue) has many taste buds on it
• There are four primary types of taste: sweet, salty, sour and bitter *THIS IS VERY LIKELY TO BE ON THE EXAM*
• MSG (monosodium glutamate) is a flavour enhancer found most frequently in Chinese food. Some people have an intolerance to it, which makes their taste bud activators really sensitive at first and then really insensitive so that they can't taste much. As Mr. Macaraeg would say the taste it like "wow wow wow and then nothing"

Sense of Smell

• Smell receptors in your nose are called olfactory receptors
• About 80-90% of what we "taste" actually comes from smell, which explains why when we're sick food tastes more dull than usual
• Olfactory cells are modified neurons, and each cell ends in a tuft of 5 cilia.
• Odor = aroma = smell

Here are some links to videos that deal with what we learned today:

How smell and taste are related

Sense of Taste