Category Zoology

Why is food nutrition important?

Nutrition is the food your body needs to grow, move, and keep all its parts working. The body can make some of the substances it needs, but the rest have to come from the food we eat. The digestive system breaks food down into simple chemicals called nutrients that the body can use. Nutrients energize the cells ready for work, provide material for new tissues, and help to repair injuries.  

Good nutrition is an important part of leading a healthy lifestyle. Combined with physical activity, your diet can help you to reach and maintain a healthy weight, reduce your risk of chronic diseases (like heart disease and cancer), and promote your overall health.

The link between good nutrition and healthy weight, reduced chronic disease risk, and overall health is too important to ignore. By taking steps to eat healthy, you’ll be on your way to getting the nutrients your body needs to stay healthy, active, and strong. As with physical activity, making small changes in your diet can go a long way, and it’s easier than you think!

 

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What is inside the stomach?

The stomach’s wall has three muscle layers that run in different directions. During digestion, these contract in turn to churn food while mixing it with acidic gastric juice. Thick mucus stops gastric juice from damaging the stomach’s own delicate lining.

Pylric sphincter

Normally closed to keep food in the stomach, this ring of muscle opens slightly once food has been processed to allow a controlled flow or chyme into the duodenum.

Duodenum

The duodenum is the first of the three parts of the small intestine that receives partially digested food from the stomach and begins with the absorption of nutrients. It is directly attached to the pylorus of the stomach. The first part of the small intestine is about 25 cm (10 in) long.

Gastric mucosa

The stomach’s inner layer contains gastric glands. The mucosa is always covered by a layer of thick mucus that is secreted by tall columnar epithelial cells. Gastric mucus is a glycoprotein that serves two purposes: the lubrication of food masses in order to facilitate movement within the stomach and the formation of a protective layer over the lining epithelium of the stomach cavity. 

Oesophagus

Food is carried in this tube from the throat to the stomach. The upper part of the oesophagus is behind the windpipe (trachea). The windpipe is the tube that connects your mouth and nose to your lungs, so you can breathe. Below your lungs is a layer of muscle called the diaphragm. It helps you to breathe. Most of your oesophagus sits above the diaphragm in your chest.

Serous layer

The stomach is covered by this protective layer. Serous membranes have two layers. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity.

Longitudinal muscle

This layer runs the length of the stomach. This layer is composed of smooth muscle, continuous with the smooth muscle which surrounds the esophagus. Below this longitudinal muscle is the Auerbach’s plexus, or myenteric plexus, above the middle circular. 

Circular muscle

This layer wraps around the stomach. It wraps in a circular orientation around the pylorus, and is held in a constricted state normally. The normal constriction of this muscle is what creates the pyloric sphincter, which controls the movement of chyme into the duodenum. This layer is concentric to the longitudinal axis of the stomach. 

Oblique muscle

This layer runs diagonally.  It wraps around the body of the stomach, extending downward to form the pyloric sphincter along with the circular muscle layer. This layer is responsible for creating the motion that churns and physically breaks down the food. It is the only layer of the three which is not seen in other parts of the digestive system. 

Gastric pits

These pits lead to the gastric glands, which make and release gastric juice. This liquid contains a mixture of enzymes, hydrochloric acid, and mucus.

Rugae

Deep folds in the stomach wall disappear when it stretches, as it fills the food. The inner layer of the stomach is full of wrinkles known as rugae (or gastric folds). Rugae both allow the stomach to stretch in order to accommodate large meals and help to grip and move food during digestion.

Protective coat

Thick fluid coats and lining, preventing the stomach from being digested by its own gastric juice. The mucus protects the gastric mucosa from auto digestion by e.g. pepsin and from erosion by acids and other caustic materials that are ingested. Bicarbonate ions, secreted by the surface epithelial cells.

 

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Why three major telescopes hit the headlines in 2020?

China’s Five-hundred-metre Aperture Spherical Radio Telescope (FAST) passed national evaluation and officially began operation in January 2020. With a dish the size of 30 football fields, it is the world’s largest single-dish radio telescope and the most sensitive listening device. The single-dish radio telescope is made of 4,450 individual panels.

The facility will help scientists learn more about the Universe’s early days, detect low-frequency gravitational waves and hunt for signals that may have been produced by distant alien civilizations.

  • NASA’s Spitzer Space Telescope was retired in January 2020. Launched in 2003, Spitzer studied the universe in infrared light, revealing wonders of the Solar System, our galaxy, and beyond. Among its many scientific contributions, Spitzer studied comets and asteroids in the Solar System and found a previously unidentified ring around Saturn.
  • In April 2020, the Hubble Space Telescope completed 30 years of service. Perched on the low Earth orbit, the telescope’s modest 2.4-metre mirror continues to give us an unprecedented window on the Universe. Thanks to Hubble and the Gaia space observatory, we were able to calculate the age of our Universe, which is approximately 13.8 billion years old. From observations from Hubble, we also learnt that black holes are at the centre of almost every major galaxy.

Did you know?

  • NASA’s James Webb Space Telescope (JWST) is scheduled to be launched in October 2021. While it is touted as the successor of the Hubble Space Telescope, some scientists believe the two telescopes are actually complementary. Hubble has limited capabilities at near-infrared wavelengths, but it is best suited for observing in the ultraviolet and optical ranges of the light spectrum. Whereas James Webb is perfectly poised to study things in infrared range and these include formation of stars and planets, extremely distant galaxies, and even the atmospheres of exoplanets.
  • The Hubble’s mission ends in 2021, unless NASA decides to extend it.

 

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Should people keep primates in zoos?

Primates are happiest in the wild, but zoos do important work. They breed animals that are becoming endangered, such as the golden lion tamarin or the silvery marmoset. Zoos also help people to learn about their ape and monkey cousins. This helps people to understand better why primates should be protected in the wild.

Amazing! Some people think that there are primates yet to be discovered – abominable snowmen! There are many tales of monstrous primates in remote parts of the world, including the yeti from central Asia.

Why are primates in danger?

Not all primates are threatened, but some are. Some, such as the emperor tamarin with its beautiful whiskery moustache, are caught to be sold as pets. Gorillas and orang-utans are in danger because people are destroying their habitat and are also hunting them. There are only about 650 gorillas left in the wild.

Is it true? People eat chimp and chips.

No. A few apes and monkeys are caught for food, but the biggest threats are the pet trade and the destruction of the places where they live.

Which primate came back from the dead?

Sometimes primates are thought to be extinct, only to re-appear. This happened with the greater bamboo lemur. Most primates are shy and good at hiding. Also, they often live in remote places which are difficult to explore.

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Which ape uses tools?

Chimps are very clever, and even make simple tools. They sometimes strip a stick of its bark to make a kind of fishing rod that they use to fish for termites. They also use sticks to gather honey so they needn’t get too close to the nest and risk a nasty bee sting!

Amazing! Chimps take medicine. Chimpanzees sometimes eat plants that don’t taste very nice at all, as cures for illness. One herbal remedy is aspilia, which gets rid of tummy upsets and worms.

Can apes paint?

Tame chimps and gorillas have been given paints and paper so they can make pictures. Some of the results look like the work of human artists, and foxed a few of the so-called experts who couldn’t tell the difference!

Is it true? Chimps can talk.

No. People have taught chimps to point at symbols and to use sign language, so we know that they are clever enough to understand language. But chimps’ vocal cords are unable to produce spoken words like ours.

Who carries a pet stone?

Chimpanzees who live on Mount Tai, in West Africa, use a stone as a nutcracker to smash open the hard shells of the coula nut. There aren’t many rocks on the mountain, so each chimp carries around its own favourite stone.

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Who’s the king of the swingers?

Gibbons are the champion swingers. They have special bones in their wrists and shoulders to give them plenty of swing as they move from tree to tree. These long-armed apes live in the tropical forests of Malaysia and Indonesia.

Amazing! Primates have their own cushions. Many primates, including baboons which spend a lot of time sitting around, have built-in padding on their bottoms.

What hangs by the tail?

Woolly monkeys, spider monkeys and howler monkeys all have a bare patch of tail for extra grip. They are the only primates that can support all their weight with the tail and hang upside-down.

When are two legs better than four?

Crossing open ground can be a dangerous business with predators about. Lemurs can travel much more quickly on two legs than four. Standing upright also gives them a better view, and frees up their front legs, to pick up food.

Is it true? Slow lorises really do move slowly.

Yes. Lorises are the most relaxed primates. Unlike their busy monkey cousins, lorises stroll very slowly through the forest in search of food.

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