Placeholder Image

字幕表 動画を再生する

  • It's AumSum Time.

  • Why do bees die when they sting us?

  • I don't know.

  • But it sounds super sad.

  • Yes.

  • Honeybees are the only bees that die after stinging.

  • But if they die, why do they sting?

  • Bees only sting when they feel we are a threat to their queen or their hive.

  • Now, the stinger of a honeybee is barbed.

  • After stinging, it can easily come out, if the skin is thin.

  • But since human skin is thick, the barbed stinger gets stuck.

  • Hence, when the bee tries to pull herself, she ends up tearing the abdomen.

  • Leaving behind her venom sac, parts of the digestive tract, etc. and thus, killing herself.

  • Now, although the bee is dead, we should make sure that we remove the sting.

  • Why?

  • Because in spite of being detached from the bee.

  • The venom sac continues to pump venom, thus increasing the pain.

  • How do scars form?

  • It is a secret process.

  • I cannot reveal it.

  • No.

  • It's not a secret process.

  • A scar is formed when our skin tissue heals itself after an injury.

  • Our skin tissue has collagen.

  • Collagen is a structural protein produced by fibroblasts.

  • Collagen keeps our skin firm and it is usually arranged in a basket weave pattern.

  • Can I use this basket to keep my bags of chips?

  • Please listen.

  • When we get injured, our skin tissue gets damaged.

  • So, in order to heal and close the wound, fibroblasts produce more collagen.

  • But, instead of arranging in a basket weave pattern.

  • The collagen cross links and aligns in a single direction.

  • As a result.

  • The injured area of the skin appears different from normal skin, thus causing a scar.

  • Why do our muscles get sore?

  • Because they want to go to a spa.

  • No.

  • When we begin to go to gym or perform a new intense physical workout.

  • Our muscles begin to feel sore the next morning.

  • This soreness is called Delayed Onset Muscle Soreness or DOMS.

  • DOMS occurs usually after eccentric contractions.

  • What does that even mean?

  • When a muscle is lengthening and contracting at the same time.

  • It is known as an eccentric contraction.

  • For example, when we lower a dumbbell.

  • Our biceps muscle is slowly relaxing and lengthening.

  • But at the same time, it is still contracting to hold the heavy weight of the dumbbell.

  • Similarly, in a squat, as we lower ourselves, our quadriceps muscle is lengthening.

  • But at the same time, it is still contracting to hold our upper body weight.

  • Such eccentric contractions generate tension in the muscles.

  • Creating minute tears in them, thus, causing the soreness or pain.

  • Can animals get a sunburn?

  • Yes.

  • Due to ultraviolet radiation of the sun, animals can also get sunburns.

  • However, to protect themselves from the harmful radiation.

  • Different animals have different biological defenses.

  • For example, reptiles have scales, birds have feathers.

  • Animals like sheep, dogs and cats have fur or hair.

  • Sperm whales have a special protein, fin whales have more melanin, etc.

  • Does anybody have Captain America's shield?

  • Please listen.

  • Some animals even produce certain substances to protect themselves from the harmful radiation.

  • For example, hippopotamuses secrete a fluid made up of red and orange pigments.

  • Some fish, amphibians, reptiles and birds produce a chemical called gadusol.

  • In addition to this, animals like rhinoceroses, elephants and pigs take mud baths.

  • It is said that mud acts like a physical barrier between their skin and ultraviolet radiation.

  • Thus preventing them from getting sunburns.

It's AumSum Time.


B2 中上級

Why do Bees Die when they Sting us? | #aumsum

  • 105 2
    AumSum   に公開 2019 年 08 月 05 日