VIDEOS

• The heart is one of the most vital organs of the human body and is located on the middle left side of your chest
• Heart's important job


  Pump blood through the circulatory system, providing oxygen-rich blood required for staying alive
• How the heart works

  1. Blood enters the right atrium

  2. Goes through the tricuspid valve to the right ventricle

  3. Pumped through the pulmonary valve and pulmonary artery to the lungs

  4. Oxygenated blood travels back through the pulmonary vein to the left atrium

  5. Through the mitral valve to the left ventricle

  6. Pumped out to the rest of the body
• The human heart pumps about 2,000 gallons of blood every day
• The human heart beats about 100,000 times in one day and approximately 35 million times a year during an average lifetime
• Brain


  The boss of your body, controls everything you do - learning, thinking, feeling, dancing, breathing, heart rate
• Different parts of the brain and their functions

  • Cerebrum (largest part, controls muscles and thinking)
  • Cerebellum (maintains balance and regulates motor movements)
  • Brain stem (controls breathing, heart rate, digestion)
  • Amygdala (responsible for emotions, survival instincts, storing memories)
• The brain generates about 12 to 25 watts of electricity, enough to power a low voltage LED light
• After exercise, the body produces a chemical that makes the brain more willing to learn
• Skin


  An essential barrier or first line of protection against the outside environment, part of the sense of touch
• Layers of the skin

  • Epidermis (outer layer, waterproof barrier, contains melanin)
  • Dermis (contains connective tissue, hair follicles, sweat glands, nerve endings)
  • Hypodermis (subcutaneous tissue, made of fat and connective tissue)
• The skin is the largest organ in the human body, occupying nearly 1.73 square meters or more than 18.5 square feet
• Urinary system


  Disposes of liquid waste, filters blood in the kidneys, stores urine in the bladder, expels urine through the urethra
• Holding in urine for too long can weaken the bladder muscles and lead to urinary retention
• Nose


  Allows you to smell, breathe, filters, warms and moistens air before it reaches the lungs
• Olfactory epithelium


  Contains receptors that detect smells and send signals to the brain
• Anosmia is the inability to perceive odour or a lack of functioning olfaction
• How hair grows


  1. Hair follicles in the skin

  2. Hair bulb at the bottom of the follicle contains hair growing cells

  3. Blood vessels in the skin provide nutrients to the hair bulb

  4. Hair shaft grows out of the follicle and through the skin surface
• You have over 100,000 hairs on your head, and lose 50-100 strands per day which are replaced by new growth
• You have more than 100,000 hair on top of your head but you lose some every day and you lose nearly 50 to 100 strands of hair every day while you're washing your hair combing it or even when you do nothing
• Your body has covered it for you as new hair regularly replaces those that have fallen out
• Hair growth cycle


  Each hair grows around two to six years and rests for a few months before it finally falls out just to be replaced by a new hair growing from the same hair follicle
• Nails protect the tip of your fingers and toes from injuries and make it easier to scratch an edge
• Doctors can get clues about your health condition by observing the condition of your nails
• Nail material


  Keratin, the same protein that makes up hair and outer layer of the skin
• Nail growth


  1. Nail cells grow and produce the protein called keratin

  2. New cells force the old ones to get packed together and pushed up through the skin

  3. Eventually the cells lose the ability to multiply and die to form the visible nail plate
• Lunula


  The small whitish half moon shape at the bottom of your nails, named after the Latin word for moon
• Trimming nails regularly is necessary to remove dirt and dust particles that get under the nail and skin
• Auditory system


  Comprised of the ears and the brain, converts sound energy into neural signals processed by the brain
• How hearing works


  1. Sound waves enter the outer ear

  2. Vibrate the eardrum in the middle ear

  3. Cause the ossicle bones to move

  4. Create waves in the cochlear fluid in the inner ear

  5. Move the hair cells to generate nerve signals sent to the brain
• Not all living creatures hear with ears, some use other methods like jaw bones, pressure changes, or antennae
• Types of teeth


  • Incisors
  • Canines
  • Premolars
  • Molars
  • Wisdom teeth
• Teething


  The process of baby teeth coming through the gums, starting around 6-12 months old
• Permanent teeth


  Replace the primary/baby teeth, usually completed by age 12-13
• Wisdom teeth sometimes need to be removed as they can crowd and damage other teeth
• Right-handed people chew food on the right side, left-handed people chew on the left
• Tongue functions


  • Perceive taste and texture of food
  • Assist in speech
  • Start the digestive process
• There are between 3,000 and 10,000 taste buds on the human tongue
• Some animals like frogs, chameleons, and blue whales have very large, specialized tongues
• Muscle growth


  1. Brain sends signals to motor neurons

  2. Muscles contract and relax, pulling on bones

  3. Muscle damage causes inflammation and repair, making muscles bigger and stronger