The Digestive System

Purpose of the Digestive System•Turning food into microscopic nutrients

that can be absorbed through the intestinal lining

•What is the toughest food that the human body might try to break down?

▫Fibre – made from plants (vegetables and grains)

How does food get broken down?•Mechanically

▫Mouth chews food to break it into smaller pieces

▫Stomach churns

•Chemically ▫Liver produces bile to mix water and fat

together for digestion▫Gastric acid is produced by the cells of the

stomach lining (it would burn your hand!)

Structure of the Digestive Tract

•http://medtropolis.com/virtual-body/

The Importance of the Sphincter•Without a sphincter, the digestive track is

really just a hole through your body

•Sphincter – a ring of muscle that holds a biological opening closed

•Over 50 different sphincters in the human body

Two Types of Sphincter’s •Voluntary - Controllable▫Rectum – both voluntary and involuntary sphincter’s

▫Sphincter Urethrae - Urinary sphincter

2 Types of Sphincter’s•Involuntary - Not in your control▫Ileocecal valve – closes off the small intestine so that food that has not fully broken down may not pass

▫Sphincter pylori – Holds food in the stomach until it is thoroughly mixed with stomach acid

Olestra•Fat substitute used in the 1980’s

•zero calories, zero grams of cholesterol and zero grams of fat

•gastrointestinal symptoms — including diarrhea, loose stools, nausea, gas

•Olestra sometimes causes underwear staining•“greasy, hard-to-wipe-off fecal matter”•anal leakage (leakage of liquid olestra through

the anal sphincter).

My Roomate

•He did not have an esophogeal sphincter

•Always got heart burn (acid moving up from your stomach into your esophagus)

•Had a muscle from his leg fashioned into a sphincter to prevent it

Demo

•Digestion of Fat -

What’s wrong with me Doc?

•Day 1:▫Pain in stomach area

•Answers:▫Lot’s of fibre, good amount of veggies, not

too much red meat▫2 days of on and off pain▫Bowel movements – 1-2/day (regular)

What’s wrong with me Doc?

•Day 2: Pain moves down and to the right side▫Excrutiating pain when I walk▫Some nausea and vomiting

•Answers:•I know I have collitis. Do I have collitis?

How could I test for it?

The Circulatory System

Purpose of the Circulatory System•Transports nutrients and oxygen to cells

•Transports waste and carbon dioxide away from cells

Getting Around the Body

•The heart pumps blood through the body

•It pumps blood to the lungs to exchange gases and comes back to the heart

•The heart then pumps blood around the rest of the body to transport gases to the cells

•Capillaries – Act as an exchange point for gases and nutrients

•These happen in the:▫Lungs▫Intestines▫Every single cell in the body

Structure of the Circulatory System

•Video

Respiratory System

Purpose of the Respiratory System•To provide all cells in the human body with Oxygen and remove Carbon Dioxide produced as waste by each cell

Fact

•You breathe 15 times per minutes and move 10,000L of air in and out of your lungs each day

•With every breath, you breath in at least one particle of air that Gandhi breathed in when he was alive

Respiratory System Structure

Gas Exchange

Carbon Monoxide Poisoning

•When we breathe in Carbon monoxide, it takes the place of oxygen on the red blood cells

•Since RBC’s cannot carry oxygen, the tissues in the human body start to malfunction

•The brain relies on oxygen and is one of the first organs affected

•You will feel nausea, head aches, loss of consciousness and more

Breathing

•You breath without having to ask your body to do so

•If you hold your breath too long, when you fall unconcious, your body will start to breathe again

Musculoskeletal System

Purpose

•The musculoskeletal system supports the body, protects delicate organs and makes movement possible

•MusclesBundles of long cells.Contract and expand when signalled by nerve cells.

Skeletal muscle attached to bone by tendons

MusclesMuscles contract – get shorter and thicker.

Muscles

Voluntary

Involuntary

Osteoporosis

Nervous System

Purpose of the Nervous System

•To sense the environment and coordinate an appropriate response

Nervous System▪ The nervous system is made up of

the brain, spinal cord,

and peripheral nerves.

▪ It senses the environment and

coordinates an appropriate

response.

▪ The core of the nervous system is

the brain and the spinal cord.

This is called the central nervous

system.

Nerves are bundles of special cells called neurons,surrounded by connective tissue.

Neurons arecommunication specialists that send informationaround the body using electrical signals.

There are approximately 100 billion neurons in the human brain.

Neuron Facts

Human brain has over 100 billion neurons

If lined up, they’d make a line over 600 miles long

Neurons do not undergo mitosis

Signals can be sent as high as 180 miles/hour

The peripheral nervous system consists of the nerves that carry the signals between the

central nervous system and the body.

Human Body is an Electrical Circuit•Let-go Voltage

Reflexes Reflexes are actions that do not

require the involvement of the brain: they occur without conscious thought.

The spinal cord acts as a short cut for reflexes.

Functional MRI (Magnetic Resonance Imaging)•Detects electrical activity in the brain

Congenital Analgesia•Congenital Insensitivity to Pain•Malfunction of path of pain signals to the brain or the brain’s failure to interpret them

•Very dangerous for children because they can hurt themselves without knowing it.

•We feel pain so we don’t injure ourselves