Every few years, carbohydrates are vilified as public enemy number one and are accused of being the root of obesity, diabetes, heart disease and more. Bodybuilders drink protein shakes for breakfast and after working out. Conquering atherosclerosis starts with improving medical education. Despite the neglect of nutrition in medical education, the public considers physicians to be among the most trusted sources for nutrition-related information. Note the important distinction between measuring protein by grams per calorie rather than by percentage of calories.
Diversity of muscle
As well as flexion and extension, it can exhibit inversion the sole of the foot faces the other leg or eversion the opposite movement. These movements are controlled by the tibialis posterior, which inverts the ankle, and the peronaeus muscles, which are antagonistic and evert it.
Ball-and-socket joints, such as the human hip , allow three degrees of freedom. Most animal joints have at least two muscles an antagonistic pair for each degree of freedom.
Seldom are muscle fibres as long as a muscle, but many muscles, such as the biceps in the human arm , are composed of relatively long fibres lying nearly parallel to each other. These parallel muscles are attached to tendons or apodemes in arthropods, chitinous rods that serve as sites for muscle attachment only at their extreme ends.
Since muscle fibres can contract about one-third of their resting length, this arrangement is suitable to an extensive and quick movement. The deltoid muscle in the human shoulder is said to be pennate; relatively short fibres attach diagonally onto a tendon that penetrates far into the muscle. The ankle muscles shown in Figure 4B are pennate muscles, but most of the hamstring muscles at the back of the thigh are parallel. The adductor muscles of the shells of clams are parallel, but most of the leg muscles of arthropods are pennate.
A pennate muscle may contain many more and shorter fibres than a parallel muscle of equal mass. Therefore, the pennate muscle can exert a greater force but cannot shorten a great deal; the parallel-fibred muscle can exert only a relatively small force but can shorten significantly. The presence of pennate muscle in a given structure may have the same effect as a longer lever arm.
In the slender legs of arthropods, with insufficient space for bulky muscles or long lever arms, many of the muscles are pennate. Tendons and apodemes have elastic properties. Tendons in the legs of mammals serve as springs, reducing the energy cost of running: An apodeme in the hind legs of locusts , for example, is one of the important elastic elements in the catapult mechanism that powers jumping.
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Davies Bernard Wood David M. Warshaw …See All Contributors. Read More on This Topic. Page 1 of Next page Muscle in soft animals. Learn More in these related Britannica articles: Human muscle system , the muscles of the human body that work the skeletal system, that are under voluntary control, and that are concerned with movement, posture, and balance.
Broadly considered, human muscle—like the muscles of all vertebrates—is often divided into striated muscle or skeletal muscle , smooth muscle, and cardiac muscle. About 40 percent of the body weight of a healthy human adult weighing about 70 kilograms pounds is muscle, which is composed of about 20 percent….
The respiratory muscles displace the equilibrium of elastic forces in the lung and chest in one direction or the other by adding muscular contraction. During inspiration, muscle contraction is added to the outward elastic force of the chest to increase the traction on the…. The cardiac heart muscles and smooth muscles of the viscera of birds resemble those of reptiles and mammals. The smooth muscles in the skin include a series of minute feather muscles, usually a pair running from a feather follicle to each of….
The muscular system of mammals is generally comparable to that of reptiles. With changes in locomotion, the proportions and specific functions of muscular elements have been altered, but the relationships of these muscles remain essentially the same.
Exceptions to this generalization are the muscles…. More About Muscle 49 references found in Britannica articles Assorted References component of meat In meat processing: Conversion of muscle to meat protein composition In actin In protein: The muscle proteins anatomy human body In human body: Organization of the body mechanical senses and receptors In senses: Mechanical senses specialization In morphology: Histology tissue classification In tissue: Animals biochemistry effects of aging process In aging: Changes in body composition, metabolism, and activity curare In curare drugs and drug action In drug: Drugs affecting muscle View More.
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Thank You for Your Contribution! This is because under ripe bananas contain more resistant starches which break down more slowly in the body That being said, if you are between consuming any food that is packaged, processed, and full of artificial ingredients, a banana is always going to be the better choice even if you do have blood sugar issues or weight to lose.
Bananas are also less carbohydrate-rich than many grains are, so I even encourage you to have a banana over something like oats, cereals, rice, or other grains. When you do a side-by-side comparison of bananas against other grains, you are ultimately consuming less carbs, sugar, calories, and more nutrients when you choose the banana. Bananas spread across regions of the Middle East and North Africa, including areas of Egypt and Palestine, around the 9th and 10th centuries.
They were even mentioned in Ancient Islamic Texts. When explorers from the Middle East and Europe began to travel to Central and South America, they brought bananas along with them on their journeys, introducing the fruit to an entirely new population.
Portuguese explorers were the first to bring bananas to newly discovered regions and populations in this area where they are still highly consumed today. Bananas were easily grown in the tropics of South and Central America, so they quickly began to be harvested in large quantities while their popularity spread up to North America. Today, areas of the Caribbean and Central and South America are still regions that grow high amounts of bananas, specially Brazil, Ecuador, and Colombia.
Today, the Cavendish banana is the most common type of banana sold. Worldwide, most nations do not make a distinction between bananas and plantains and use them almost interchangeably. Bananas constitute a major staple food crop for millions of people living in developing countries today across Latin America, Africa, India and the South Pacific. They are an important crop because they grow in abundance year-round and are very inexpensive. Banana chips are a great addition to a grain-free granola to add a little extra boost of energy after a workout or when you hit that afternoon slump.
It is best to slice and dehydrate your bananas yourself whenever possible. So double check the ingredients when purchasing or try to get from an organic market and ask what oil they use or if they are dehydrated.
This is because bananas are enclosed in a thick peel, helping to block them from absorbing many of the harsh chemicals and toxins that are sprayed on crops. Bananas grow high up in trees where they are generally safer from rodents, animals, and certain bugs; therefore they are sprayed less with pesticides and herbicides than some other foods typically are. Bananas are extremely versatile in recipes, even standing in for things like sugar, refined oils, processed flours, and more.
Because bananas are sweet tasting and contain moisture, they make a great substitute ingredient in recipes for less healthy foods and added sugar. One of the most popular ways to consume bananas is to add one to a healthy smoothie recipe. But you can also eat bananas plain, have them with nut butter, or use them in things like healthy pancakes, muffins, and breads.
Try incorporating bananas into your diet using some of these simple and healthy recipes below. This gluten free and grain-free banana bread recipe is a great snack. Try this awesome classic and let me know what you think! This chocolate banana nut smoothie recipe is delicious and healthy! Place all ingredients in a blender and blend until desired consistency is reached.
Coconut is one of the healthiest foods you can eat! Coconut is a medium chain fatty acid which are easily digested and converted to energy instead of being stored as fat. Because of this, coconut aids in weight loss, helps to stimulate the metabolism and has amazing anti microbial properties.
Try this recipe and experience its benefits today! What is your favorite benefit of banana nutrition? From the sound of it, you might think leaky gut only affects the digestive system, but in reality it can affect more. The tongue is utilized to roll food particles into a bolus before being transported down the esophagus through peristalsis. The sublingual region underneath the front of the tongue is a location where the oral mucosa is very thin, and underlain by a plexus of veins.
This is an ideal location for introducing certain medications to the body. The sublingual route takes advantage of the highly vascular quality of the oral cavity, and allows for the speedy application of medication into the cardiovascular system, bypassing the gastrointestinal tract. Teeth singular tooth are small whitish structures found in the jaws or mouths of many vertebrates that are used to tear, scrape, milk and chew food.
Teeth are not made of bone, but rather of tissues of varying density and hardness, such as enamel, dentine and cementum. Human teeth have a blood and nerve supply which enables proprioception. This is the ability of sensation when chewing, for example if we were to bite into something too hard for our teeth, such as a chipped plate mixed in food, our teeth send a message to our brain and we realise that it cannot be chewed, so we stop trying.
The shapes, sizes and numbers of types of animals' teeth are related to their diets. For example, herbivores have a number of molars which are used to grind plant matter, which is difficult to digest. Carnivores have canine teeth which are used to kill and tear meat. A crop , or croup, is a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion. In some birds it is an expanded, muscular pouch near the gullet or throat.
In adult doves and pigeons, the crop can produce crop milk to feed newly hatched birds. Certain insects may have a crop or enlarged esophagus. Herbivores have evolved cecums or an abomasum in the case of ruminants. Ruminants have a fore-stomach with four chambers. These are the rumen , reticulum , omasum , and abomasum. In the first two chambers, the rumen and the reticulum, the food is mixed with saliva and separates into layers of solid and liquid material.
Solids clump together to form the cud or bolus. The cud is then regurgitated, chewed slowly to completely mix it with saliva and to break down the particle size.
Fibre, especially cellulose and hemi-cellulose , is primarily broken down into the volatile fatty acids , acetic acid , propionic acid and butyric acid in these chambers the reticulo-rumen by microbes: In the omasum, water and many of the inorganic mineral elements are absorbed into the blood stream.
The abomasum is the fourth and final stomach compartment in ruminants. It is a close equivalent of a monogastric stomach e. It serves primarily as a site for acid hydrolysis of microbial and dietary protein, preparing these protein sources for further digestion and absorption in the small intestine.
Digesta is finally moved into the small intestine, where the digestion and absorption of nutrients occurs. Microbes produced in the reticulo-rumen are also digested in the small intestine. Regurgitation has been mentioned above under abomasum and crop, referring to crop milk, a secretion from the lining of the crop of pigeons and doves with which the parents feed their young by regurgitation.
Many sharks have the ability to turn their stomachs inside out and evert it out of their mouths in order to get rid of unwanted contents perhaps developed as a way to reduce exposure to toxins. Other animals, such as rabbits and rodents , practise coprophagia behaviours — eating specialised faeces in order to re-digest food, especially in the case of roughage. Capybara, rabbits, hamsters and other related species do not have a complex digestive system as do, for example, ruminants.
Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft faecal pellets of partially digested food are excreted and generally consumed immediately. They also produce normal droppings, which are not eaten. Young elephants, pandas, koalas, and hippos eat the faeces of their mother, probably to obtain the bacteria required to properly digest vegetation.
When they are born, their intestines do not contain these bacteria they are completely sterile. Without them, they would be unable to get any nutritional value from many plant components. An earthworm 's digestive system consists of a mouth , pharynx , esophagus , crop , gizzard , and intestine. The mouth is surrounded by strong lips, which act like a hand to grab pieces of dead grass, leaves, and weeds, with bits of soil to help chew.
The lips break the food down into smaller pieces. In the pharynx, the food is lubricated by mucus secretions for easier passage. The esophagus adds calcium carbonate to neutralize the acids formed by food matter decay. Temporary storage occurs in the crop where food and calcium carbonate are mixed. The powerful muscles of the gizzard churn and mix the mass of food and dirt. When the churning is complete, the glands in the walls of the gizzard add enzymes to the thick paste, which helps chemically breakdown the organic matter.
By peristalsis , the mixture is sent to the intestine where friendly bacteria continue chemical breakdown. This releases carbohydrates, protein, fat, and various vitamins and minerals for absorption into the body. In most vertebrates , digestion is a multistage process in the digestive system, starting from ingestion of raw materials, most often other organisms. Ingestion usually involves some type of mechanical and chemical processing.
Digestion is separated into four steps:. Underlying the process is muscle movement throughout the system through swallowing and peristalsis. Each step in digestion requires energy, and thus imposes an "overhead charge" on the energy made available from absorbed substances.
Differences in that overhead cost are important influences on lifestyle, behavior, and even physical structures.
Examples may be seen in humans, who differ considerably from other hominids lack of hair, smaller jaws and musculature, different dentition, length of intestines, cooking, etc.
The major part of digestion takes place in the small intestine. The large intestine primarily serves as a site for fermentation of indigestible matter by gut bacteria and for resorption of water from digests before excretion. In mammals , preparation for digestion begins with the cephalic phase in which saliva is produced in the mouth and digestive enzymes are produced in the stomach. Mechanical and chemical digestion begin in the mouth where food is chewed , and mixed with saliva to begin enzymatic processing of starches.
The stomach continues to break food down mechanically and chemically through churning and mixing with both acids and enzymes. Absorption occurs in the stomach and gastrointestinal tract , and the process finishes with defecation.
The human gastrointestinal tract is around 9 meters long. Food digestion physiology varies between individuals and upon other factors such as the characteristics of the food and size of the meal, and the process of digestion normally takes between 24 and 72 hours.
Digestion begins in the mouth with the secretion of saliva and its digestive enzymes. Food is formed into a bolus by the mechanical mastication and swallowed into the esophagus from where it enters the stomach through the action of peristalsis. Gastric juice contains hydrochloric acid and pepsin which would damage the walls of the stomach and mucus is secreted for protection.
In the stomach further release of enzymes break down the food further and this is combined with the churning action of the stomach. The partially digested food enters the duodenum as a thick semi-liquid chyme.
In the small intestine, the larger part of digestion takes place and this is helped by the secretions of bile , pancreatic juice and intestinal juice. The intestinal walls are lined with villi , and their epithelial cells is covered with numerous microvilli to improve the absorption of nutrients by increasing the surface area of the intestine.
In the large intestine the passage of food is slower to enable fermentation by the gut flora to take place. Here water is absorbed and waste material stored as feces to be removed by defecation via the anal canal and anus. Different phases of digestion take place including: The cephalic phase occurs at the sight, thought and smell of food, which stimulate the cerebral cortex.