Why don't haircuts hurt?
Hair is made up of dead cells, so you don't feel a thing.The dead hair cells are fillrd with a tough, waterproof protien called Keratin, as are nails, and the skin flakes that you lose daily in their millions from your skin's surface. All these things are part of the fantastic protective overcoat that covers and protects your body.
Facts: In an average lifetime a man will shave 20,000 times( unless, of course, he has beard).
What's in skin?
Skin is really thin but also quite complex. It is mase up of two layers:
The epidermis provides protection, and is constantly worn away and replaced. The dermis glues the epidermis to the rest of the body, and deals with feelings, temperature control, and food and oxygen supplies.
Six reasons you need skin:
1. It provides a waterproof covering around your body.
2. It forms a barrier between your delicated tissues and the harsh outside world.
3. It stops germs getting in your body.
4. It filters out harmful ultravoilet radiation in sunlight that can damage your cells.
5. It helps your body maintain a steady temperature.
6. It houses receptors that enable you to detect touch, pressure, vibrations, heat and cold.
Spots form when oily sebum blocks a hair follicle. Bacteria move in and their activities alert the body's defences, so the spot becomes inflamed. Spot are common during puberty, when the skin is more oily.
Facts In numbers:
There are 2 sq m(21 sq ft) total surface area of an adult's skin.
The weight of ana adult man's skin is 3.2kg (7 lbs).
The number of cells in the skin are 300 million.
The thickness of the thickest skin(on the soles of the feet) is 4.7 mm(0.2 in).
The thickness of the thinnest skin(on the eyelids) is 0.12 mm(0.005 in).
The person has 2.5 million numbers of sweat pores.
The 50,000 of skin flakes lost every minute.
The number of hairs on a person's head is 100,000.
The average number is 80 of head hairs lost and replaced daily.
The amount head hair grows in a month is 10 mm(0.4 in).
5mm(0.2 in the fingernails grow in summer (less in winter).
Why armpits smells unpleasent?
Armpit sweat glands produce a thicker sweat than the body's other sweat glands. When bacteria feed on this sweat they release chemicals that can smell musky and unpleasent body odur.
You don't believe it!
People who suffer from a rare inherited conditions called congenital generalized hypertrichosis have hair covering almost their entire body. The only hairless parts are the palms of their hands and soles of their feet.
How to WARM UP?
1. Go for a run on a chilly day. Instruct your body to implement temperature regulating tricks.
2. Pull the hairs in your skin upright to trap heat. The goosebumps will die down once you are warm again.
3. Narrow the blood vessels in your dermis, helping them to lose less heat through your skin's surface.
How to COOL DOWN?
1. You're all hot and bothered after your run. Cool down by employing more temperature regulation.
2. Pour sweat onto the skin's surface so it can evaporate and draw heat from your body.
3. Widen your blood vessels in the dermis so that they lose heat like radiators through the skin's surface.
Why does your head flop when you sleep?
When you are awake the muscles in your neck and back hold you and your head upright. When you nod off, those muscles relax and your heads falls to one side. Muscles do more than just support you - by pulling your bones they produce every movement from lifting a pen to running a marathon.
There are three types of fitness:
1. Stamina: Measures how efficiently your heart pumps blood.
2. Strength: Measures how strong your muscles are.
3. Flexibility: Measures how flexible your joints, tendones, and muscles are.
Muscles:
Muscles cannot attach directly to bones. Instead, tendons, which are like tough cords, connect muscles with bones. Look at the back of your hand and wiggle your fingers and you will see tendons moving. Those particular ones extended all the way from muscles in the forearm to your finger bones.
Stretch before exercise to prevent cramp, which is when a muscle stays contracted when it should have relaxed and causes pain.
There are three types of muscles:
Skeletal muscles: Pulls on bones so you can move your body.
Smooth muscles: Found in the walls of hollow organs, such as the bladder.
Cardiac muscles: Found in the wall of the heart, it constantly contracts to pump blood.
Major Muscles:
Orbicularis oculi: Closes the eye.
Deltoid: Raises the arm sideways and swings it backwards and fordwards.
Pectoralis major: Pulls the arm fordwards and towards the body.
External oblique: Bends and twists the upper body.
Quadriceps femoris: Bends the thigh at the hip and straightens the knee.
Latissimus dorsl: Pulls the arm downwards, inwards and backwards.
Tricep brachii: Straightens the arm from the elbow.
Gluteus maximus: Straightens the hip by pulling the thigh back.
Hamstrings: Straightens the thigh at the hip and bend the knee.
Gastrocnemius: Pulls the Achilles tendon to point the foot downwards.
How to straighten and bend your arms:
1. Straighten your arm with your tricep muscles, which will pull your forearm downwards.
2. To bend your arm, contract (shorten) your biceps so it pulls your forearm upwards.
3. As your biceps keeps contracting (feel the bulge!), relax your triceps muscle to enable your arm to keep bending from elbow.
4. Your biceps is now fully contracted and your arm bent.. time to straighten it again?
Facts In numbers:
There are 640 number of skeletal muscles in the human body/
The length of the longest muscles in your body, the sartorius is 50 cm(20 in), which is a thigh muscles.
The 40-50% proportion of the male body's weight is made up by muscles.
The 30-40% proportion of the female body's weight is made up by muscles.
The length of the shortest muscle in your body, the stapedius is 0.5 cm(0.25 in), which is located in your ear.
Facial Expressions: More than 30 small muscles pulls on the skin of the face to produce the expression that reveal how we feal.
Some Facial expressions:
Fear: Muscles pull the lower jaw downwards to open the mouth wide.
Anger: Muscles pull the eyebrows downwards, making them wrinkle.
Joy: Muscles pull and lift the corners of the mouth.
Surprise: Muscles raise the eyebrows and make the forehead wrinkle.
Sadness: Muscles pull the corners of the mouth downwards.
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