Note Book 1

Functions of the skin

The skin is multipurpose, meaning it has a lot of functions.

1. It's our first line of protection against the outside environment, it houses one of our five senses, it absorbs sunlight for vitamin D and heat, and regulates our internal temperature.

2. Protection - One of the basic functions of the skin is protection. Over the majority of your body the skin is around 2mm thick. In some areas, like your eyelids, it's thinner, while in other areas, like the soles of your feet, it's much thicker. The skin helps to keep bad stuff out of our body, like germs and dirt that can cause infection. It also keeps good stuff in, like fluids such as water and blood.

3. Sense of Touch - The skin also houses one of our five senses: touch. In our skin are thousands and thousands of sensors or receptor cells. These sensors send information to the brain about things we touch. They can tell the brain if it's hot, cold, rough, smooth, or painful. Different areas of our body have more receptor cells than others. Our hands, feet, and lips all have extra receptors making those areas even more sensitive. There are actually different types of receptor cells for each type of sensation.

4. Temperature Control - The skin plays a large role in regulating our body's temperature. When we get too hot it sweats to help cool us off. It can also widen the skin's blood vessels to get more blood near the skin where it can cool off. At the same time the skin can narrow the blood vessels to help us warm up. By controlling blood flow and sweat, the skin regulates our body's temperature.

The skin has three primary layers. Each one has its own function.

Epidermis - The epidermis is the outer layer of skin. Its main function is protection. The cells on the very outer layer of the epidermis are constantly dying and getting replaced by new cells.

Dermis - The dermis is thicker than the epidermis. The dermis houses blood cells, hair follicles, and sweat glands. Hypodermis - The hypodermis lies under the dermis and connects the skin to muscles and bone.

Fact or Fake Answers:

• The tongue is a muscular structure and it is attached to the floor of the mouth. FACT

• The human tongue has 3,000 – 10,000 taste buds. FACT

• The tiny bumps you see on your tongue are your taste buds. FAKE- what you see is papillae. The taste buds sit on top of the papillae but are not visible.

• Women have longer tongues than men. FAKE- women have shorter tongues.

• The human tongue is divided into two parts: anterior and posterior. FACT

• The human tongue has eight muscles. FACT

• The average length of a human tongue is 6 inches. FAKE- the average human tongue is 4 inches.

• Saliva does not play an important role in determining the taste of food. FAKE- in order for us to taste something, it first needs to be moistened by saliva.

• Our tongue helps us to speak. FACT

• The tongue is the main sensory organ of taste. FACT

Taste Buds and Locations:

• Sweet: tip of the tongue

• Sour: both sides of the tongue

• Salty: front sides of the tongue

• Bitter: back of the tongue

• Umami: middle of the tongue