How environmental contaminants enter the body

Contaminants Some contaminants like viruses could have disastrous effects on society. This next video will help you survive them.

How Contaminants Get In Environmental contaminants can get inside the human body, causing illness, in a variety of ways. We’ll review each of the systems first: Respiratory system Digestive system Skin (integumentary system)

The Respiratory System

The Respiratory System Breathing in is called inhalation. Breathing out is called exhalation. The whole system of getting oxygen into the bloodstream and the carbon dioxide out is called the respiratory system.

How it works A muscle called the diaphragm contracts (tightens) causing the lungs to expand which draws in air. When the diaphragm expands, the air is pushed back out. You’re doing it right now.

Oxygen from the air inhaled is transferred to the blood through tiny sacs call alveoli. The oxygen taken from the air is replaced with carbon dioxide which is carried out.

Respiratory Defenses As air travels from the mouth or nose all the way down to the alveoli, it is cleaned by a few things: Moisture. The walls of the mouth and nose are wet and dirt or contaminants often stick to the sides. It is either swallowed or blown out.

2. Nose hairs. Those pesky hairs that become a real pain for men in adulthood also act as a filter to stop large airborne items from heading down your esophagus.

3. Cilia. Like your nose (but on a microscopic level) your trachea and bronchial tubes contain tiny hair-like structures called cilia that capture contaminants.

After cilia capture the contaminants, they are added to puddles of mucus (a gooey substance you’re all too familiar with!) Mucus is propelled up the bronchial tubes to the esophagus where it is then dumped into the stomach. Or coughed up on occasion.

The Digestive System

The Digestive System Since you have to eat and drink to live, stuff is always going to be getting inside of us through ingestion. Ingestion is the process of eating or drinking.

Digestion is the process food goes through starting when it is firs chewed. Food goes down the esophagus, into the stomach, then into the small intestine, then into the large intestine and out the anus.

Help from other organs Food that enters the small intestines is mixed with fluids from the liver and pancreas. The liver produces bile which helps break down and absorb fats.

The pancreas produces substances that break down carbohydrates, proteins and other fats.

Nutrient Absorption Nutrients in the food are absorbed by tiny little pillars, called villi, all along the inside of the small intestine.

Intestines You can see the villi in the small intestine in this cross section photograph.

Digestion Defenses If the body senses something isn’t quite right, it can empty its contents through vomiting. Contents from the middle of the small intestine up are forcefully thrown out of the mouth through muscle contractions.

The Liver Much of what you eat gets into your blood to be delivered to cells throughout the body. As the earlier video explained, the liver functions as a filter to get rid of contaminants in the blood.

Humans can overwhelm their liver’s natural defenses. When alcohol is consumed, it is absorbed into the bloodstream. The liver tries to filter it all out as quickly as it can since it impairs many physical functions. If it keeps happening, the liver can be harmed.

Long term alcohol abuse can cause Cirrhosis, a disease where the liver is no longer able to do its job because of alcohol damage.

Skin (Integumentary System)

Skin Skin is the first line of defense against a hostile world. Skin: Keeps pathogens and infections out Keeps the body at the right temperature Keeps the proper amount of moisture inside

Skin has three main layers: Epidermis (‘epi’ means above) Dermis Subcutaneous layer (fatty tissue) 1 2 3

Epidermis Has a top layer that you can see Has a top layer of dead cells and they often fall off Has a bottom layer of growing cells

Dermis The middle layer contains: Many tiny blood cells (capillaries) Many nerve endings for feeling Hair follicles Sweat glands

Subcutaneous Layer The layer of fat cells all around us to protect and insulate us from the cold. Sometimes it is called the hypodermis.

Absorption The skin tries to keep things out, but some things make it through. Skin can absorb some: Oils and tars Alcohols Cleaning products Pesticides medicines

Once the contaminants get through your skin, they will get into your bloodstream. The contaminants are spread throughout the body through all the blood vessels.