Digestive System

How you turn food you chew into a 'number 2'

 DIGESTIVE TRACT

DIGESTIVE TRACT

  1. Your digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells.
  2. Each of the different energy sources (carbohydrates/lipids/proteins) must be broken down into small usable particles as they travel through your digestive system.
  3. As food moves through your digestive system, nutrients and water are absorbed through various tissues

 

 

 


 MASTICATION: A 'SCIENCEY' WORD FOR CHEWING

MASTICATION: A 'SCIENCEY' WORD FOR CHEWING

Mechanical Digestion:

Involves the physical breakdown of food into very small pieces.

  • Ex. Teeth break down food in the mouth.

Chemical Digestion : 

Involves the breakdown of large particles into smaller particles by substances called enzymes.

  • Ex. Salivary amylase breaks down carbohydrates in the mouth.
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Enzymes:

A substances created by the body to carry out chemical digestion. 

  • Ex. Protease breaks down protein in the stomach

Food’s path through digestive system:

  1. Digestion begins with the mouth and the mechanical breakdown of your food by your teeth grinding your food into smaller pieces.
  2. Saliva (mouth) contains an enzyme known as salivary amylase that chemically digests large starch molecules into smaller sugar molecules.
  3. Food is funneled to the esophagus, it by-passes the windpipe which is covered by a flap of skin called the epiglottis.
  4. Food moves down toward your stomach by peristalsis.

Peristalsis :

Wave-like contractions of muscle tissue that lines the esophagus.

  • Gastric juice components, hydrochloric acid and enzymes, chemically digests proteins into smaller particles in the stomach.  The mucus helps to prevent the gastric juice from digesting the stomach itself.

Gastric Juice :

Composed of mucus, hydrochloric acid, water, and enzymes.

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5. Chemical digestion continues as the food moves into the small intestine.

6. Liver produces a substance called bile, which is stored in the gall bladder.

7. Gall bladder sends bile to the small intestine to chemically digest large globules of lipids into much smaller droplets.

8. Small intestine absorbs some nutrients.

9. Large intestine absorbs nutrients, water, along with some vitamins and minerals with its villi & microvilli.

 THIS BATHROOM MAT RESEMBLES THE LINING OF AN INTESTINAL WALL WITH VILLI

THIS BATHROOM MAT RESEMBLES THE LINING OF AN INTESTINAL WALL WITH VILLI

Villi :

Small, finger-like projections. Each villus is covered with epithelial tissue.

Microvilli :

The cells of the epithelial tissue have modified cell membranes that form more finger-like projections called microvilli.

  • Undigested material forms feces and exits the rectum.

Respiratory System

 HEALTHY LUNG VS. UNHEALTHY LUNG

HEALTHY LUNG VS. UNHEALTHY LUNG

Your respiratory system is responsible for supplying your blood with the oxygen and removing the carbon dioxide from your blood and returning it to the air outside your body.

Breathing is the process your respiratory system uses to move air in and out of your lungs.

 

 

 

 

Exhalation

  • Must increase the pressure in your lungs by decreasing the volume.
  • Decrease volume:
  • Pushing diaphragm up
  • Contracting rib cage down
  • Pressure difference forces air out of the lungs.

Inhalation

  • Must decrease the pressure in your lungs by increasing the volume.
  • Increase volume:
  • Pulling diaphragm down
  • Expanding rib cage up
  • Pressure difference forces air into the lungs.
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Diaphragm:

Large muscle below the lungs that helps move air in and out of the lungs.

Bronchi:

Two main branches of the trachea that lead into the lungs.

Alveoli:

Tiny air-filled sacs in the lungs; the site of gas exchange.


 Circulatory System

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  • The job of the circulatory system is to deliver nutrients absorbed by your digestive system to each cell in your body, transport oxygen and remove waste products.

The heart is part of the circulatory system.

  • Right side of the heart receives deoxygenated blood from your body and pumps it to your lungs (Pulmonary system)
  • Left side of the heart receives oxygen rich blood from your lungs and pumps it to your body (Systemic system)

Atria:

The upper chambers of the heart that receive blood from your lungs and body.

Ventricles:

Lower chambers of the heart that pump blood to the body.

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Arteries:

Vessels that carry blood away from your heart to all parts of your body.

Veins:

Vessels carry blood from all parts of your body towards the heart.

Capillaries :

Specialized blood vessels located between the arteries and veins that allow the diffusion of nutrients and gases.

  • Made of specialized epithelial tissue, only one layer thick.
  • They are very narrow so blood cells must go through in single file.
 BLOOD VESSEL NETWORK OF YOUR HAND

BLOOD VESSEL NETWORK OF YOUR HAND

Both of these adaptations help increase gas exchange.

Red blood cell: 

Function of red blood cells is to carry oxygen.

White blood cell:

Blood cells that are specialized to fight infections.

Platelets :

Are cells in your blood that help to stop bleeding at cuts.

Plasma:

The liquid portion of your blood, transports nutrients to your cells and carries wastes, such as carbon dioxide away.


Excretory System

Excretion : 

The removal of waste products formed in the body.

When cells break down proteins, they produce a very toxic compound called ammonia.

Urea:

The liver takes the highly toxic ammonia and converts it into less harmful substances called urea.

Kidney:

The main organs of excretion.

  • They filter the blood straining out the unwanted urea, water and other wastes, and they produce urine.
  • Deal with water regulation.
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Urine formation

  1. Renal artery brings the waste into the kidneys where the waste is filtered into the nephron.
  2. Smaller vessels then reabsorb important nutrients and water from the nephron and secrete wastes still left in the vessels
  3. The small vessels then turn into the renal vein and go back to the heart.
  4. The waste then flows from the kidneys into the ureter, which eventually leads to the bladder and urethra.

Nephrons :

Filtering units of the kidney that remove wastes from the blood and produce urine.

  •  excretes solutes (ex. salt) and produces heat.

Dialysis :

A machine that removes all the wastes from the blood that a kidney normally would.


Nervous System

 LOOK MA' NO EYELIDS!

LOOK MA' NO EYELIDS!

Nervous Tissue :

Tissue of the brain, spinal chord, and nerves.

Neurons:

Specialized cells of the nervous system that receives and transmit information.

Dendrites :

Part of the neuron that receives messages from the cell.

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Axon :

Receive the message from the dendrites, and transmit the message across synapses to other neurons.


Sensory Neurons:

Carry information from the body to the central nervous system.

Motor Neurons:

Carry information from the central nervous system to the muscles or organs.

Interneuron:

Connects one neuron to another.


Central Nervous System :

Is composed of the brain and the spinal cord.

Peripheral Nervous System :

Includes the sensory and motor neurons that carry messages to and from the central nervous system.


Somatic Nervous System:

Controls voluntary responses.

Autonomic Nervous System:

Controls automatic responses.

Reflex:

Is an automatic response by the nervous system to an external stimulus.

  • Because of possible dangers it skips the brain to save time, and reduce the impact of the danger (eg. Touching a stove).

Developing a Theory for Disease

Smallpox is a disease that produces a rash and high fever and can cause blindness and death; the first disease to be controlled by a vaccine.

Vaccine :

Substance that is taken by or injected into an animal or person to produce an immunity to a disease; usually prepared from a mild form of the disease.

  • Louis Pasteur was the first person to identify living micro-organisms.

Pasteurization:

The process of heating food.


Factors that affect the health function of body systems.

Many factors affect the health of your cells:

  1. Diseases or conditions inherited from your family.
  2. Sensitivity to environmental conditions.
  3. How you respond to physical, emotional, and psychological stress.
  4. How you treat your body in general.

The contents of cigarettes:

There are over 4000 different chemicals in a cigarette.

  1. Tar – is a dark, sticky substance that forms as a cigarette burns, settles on the surface of the organs of the respiratory system
  2. Carbon Monoxide – is a colourless, odourless gas that is released when a cigarette burns. During the gas exchange process this gas attaches to red blood cells quicker than oxygen, which can seriously reduce oxygen to the body.
  3. Nicotine – is a drug that speeds up the heart, and raises the blood pressure.  The addictive part of a cigarette.

Cigarettes can cause:

Bronchitis – occurs when mucus builds up in the bronchi and causes them to become narrower.

Emphysema – occurs when the smoke from a cigarette damages lung tissue.

Lung Cancer – 40 chemicals in a cigarette are known to cause cancer, a tumour or cancerous growth.


Basic Disease Information

1)    Asthma - is a condition where the airways become narrowed temporarily.

·      Effects the respiratory system

·      Inflammation and mucus build up blocking the bronchioles

·      Medication is usually inhaled

2)    Scurvy

·      Caused by a lack of vitamin C

·      Becomes serious with bleeding gums & losing teeth

·      Effects sailors because of a lack of fresh fruit on long voyages

3)    Atherosclerosis

·      Effects the circulatory system

·      Build up of plaque blocks arteries

·      Can lead to strokes, heart attacks, & angina

4)    Bronchitis

·      Build up of substances that block the bronchioles

·      #1 cause is smoking

5)    Smallpox

·      Eradicated by vaccinations (1st vaccine by Edward Jenner)

6)    Lung Cancer

·      #1 cause is smoking

·      Treated with Chemotherapy (radiation treatment)

7)    Food Poisoning

·      Caused by bacteria and germs (identified by Louis Pasteur)

·      Important process called Pasteurization

  Heat the milk (kills bacteria) and then cool it!

·      Fridge – slows down bacteria growth

·      Freezer – stops the bacteria growth

·      Cook – kills the bacteria (E. coli)

·      Dry/Smoked – eliminates moisture that bacteria thrive in

8)    Allergies

·      Over-response to a non-hazardous substance

·      Immune system acts too quickly

9)    Emphysema

·      #1 cause is smoking

·      Damages the alveoli and capillaries surrounding them

10)  Ulcers

·      Effects the digestive system

·      The bacteria H. pylori breaks down the mucus layer in the stomach

·      Cause painful holes in the stomach

·      Also influence by stress