Drinking

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Statue drinking from a traditional waterskin Nordkirchen-100415-12272-Trinkender.jpg
Statue drinking from a traditional waterskin
A person drinking a glass of milk Person drinking milk.jpg
A person drinking a glass of milk

Drinking is the act of ingesting water or other liquids into the body through the mouth, proboscis, or elsewhere. Humans drink by swallowing, completed by peristalsis in the esophagus. The physiological processes of drinking vary widely among other animals.

Contents

Most animals drink water to maintain bodily hydration, although many can survive on the water gained from their food. Water is required for many physiological processes. Both inadequate and (less commonly) excessive water intake are associated with health problems.

Methods of drinking

In humans

When a liquid enters a human mouth, the swallowing process is completed by peristalsis which delivers the liquid through the esophagus to the stomach; much of the activity is abetted by gravity. The liquid may be poured from the hands or drinkware may be used as vessels. Drinking can also be performed by acts of inhalation, typically when imbibing hot liquids or drinking from a spoon. Infants employ a method of suction wherein the lips are pressed tight around a source, as in breastfeeding: a combination of breath and tongue movement creates a vacuum which draws in liquid. [1]

In other land mammals

Cat lapping water in slow motion
Jack Russell Terrier laps in water with its tongue. Jack Russell Terrier takes a drink.jpg
Jack Russell Terrier laps in water with its tongue.

By necessity, terrestrial animals in captivity become accustomed to drinking water, but most free-roaming animals stay hydrated through the fluids and moisture in fresh food, [2] and learn to actively seek foods with high fluid content. [3] When conditions impel them to drink from bodies of water, the methods and motions differ greatly among species. [4]

Cats, canines, and ruminants all lower the neck and lap in water with their powerful tongues. [4] Cats and canines lap up water with the tongue in a spoon-like shape. [5] Canines lap water by scooping it into their mouth with a tongue which has taken the shape of a ladle. However, with cats, only the tip of their tongue (which is smooth) touches the water, and then the cat quickly pulls its tongue back into its mouth which soon closes; this results in a column of liquid being pulled into the cat's mouth, which is then secured by its mouth closing. [6] Ruminants and most other herbivores partially submerge the tip of the mouth in order to draw in water by means of a plunging action with the tongue held straight. [7] Cats drink at a significantly slower pace than ruminants, who face greater natural predation hazards. [4]

Many desert animals do not drink even if water becomes available, but rely on eating succulent plants. [4] In cold and frozen environments, some animals like hares, tree squirrels, and bighorn sheep resort to consuming snow and icicles. [8] In savannas, the drinking method of giraffes has been a source of speculation for its apparent defiance of gravity; the most recent theory contemplates the animal's long neck functions like a plunger pump. [9] Uniquely, elephants draw water into their trunks and squirt it into their mouths. [4]

In birds

This section is an excerpt from Bird anatomy § Drinking behaviour.[ edit ]

There are three general ways in which birds drink: using gravity itself, sucking, and by using the tongue. Fluid is also obtained from food.

Most birds are unable to swallow by the "sucking" or "pumping" action of peristalsis in their esophagus (as humans do), and drink by repeatedly raising their heads after filling their mouths to allow the liquid to flow by gravity, a method usually described as "sipping" or "tipping up". [10] The notable exception is the family of pigeons and doves, the Columbidae; in fact, according to Konrad Lorenz in 1939:

one recognizes the order by the single behavioral characteristic, namely that in drinking the water is pumped up by peristalsis of the esophagus which occurs without exception within the order. The only other group, however, which shows the same behavior, the Pteroclidae, is placed near the doves just by this doubtlessly very old characteristic. [11]

Although this general rule still stands, since that time, observations have been made of a few exceptions in both directions. [10] [12]

In addition, specialized nectar feeders like sunbirds (Nectariniidae) and hummingbirds (Trochilidae) drink by using protrusible grooved or trough-like tongues, and parrots (Psittacidae) lap up water. [10]

Many seabirds have glands near the eyes that allow them to drink seawater. Excess salt is eliminated from the nostrils. Many desert birds get the water that they need entirely from their food. The elimination of nitrogenous wastes as uric acid reduces the physiological demand for water, [13] as uric acid is not very toxic and thus does not need to be diluted in as much water. [14]

Most birds scoop or draw water into the buccal areas of their bills, raising and tilting their heads back to drink. An exception is the common pigeon, which can suck in water directly by inhalation. [4]

In insects

Drinking can be observed in many insect species. Drinking Bee2.jpg
Drinking can be observed in many insect species.

Most insects obtain adequate water from their food: When dehydrated from a lack of moist food, however, many species will drink from standing water. [15] Additionally, all terrestrial insects constantly absorb a certain amount of the air's humidity through their cuticles. [15] Some desert insects, such as Onymacris unguicularis , have evolved to drink substantially from nighttime fog. [15]

In marine life

Amphibians and aquatic animals which live in freshwater do not need to drink: they absorb water steadily through the skin by osmosis. [4] [16] Saltwater fish, however, drink through the mouth as they swim, and purge the excess salt through the gills. [16] Saltwater fishes do drink plenty of water and excrete a small volume of concentrated urine.

Hydration and dehydration

Like nearly all other life forms, humans require water for tissue hydration. Lack of hydration causes thirst, a desire to drink which is regulated by the hypothalamus in response to subtle changes in the body's electrolyte levels and blood volume. A decline in total body water is called dehydration and will eventually lead to death by hypernatremia. Methods used in the management of dehydration include assisted drinking or oral rehydration therapy.

An overconsumption of water can lead to water intoxication, which can dangerously dilute the concentration of salts in the body. Overhydration sometimes occurs among athletes and outdoor laborers, but it can also be a sign of disease or damage to the hypothalamus. A persistent desire to drink inordinate quantities of water is a psychological condition termed polydipsia. It is often accompanied by polyuria and may itself be a symptom of diabetes mellitus or diabetes insipidus. [17]

Human water requirements

Astronaut Thomas Reiter during Expedition 14 drinking water on the International Space Station ISS014-E-08330 (27 Nov. 2006) --- European Space Agency (ESA) astronaut Thomas Reiter.jpg
Astronaut Thomas Reiter during Expedition 14 drinking water on the International Space Station

A daily intake of water is required for the normal physiological functioning of the human body. The USDA recommends a daily intake of total water: not necessarily by drinking but by consumption of water contained in other beverages and foods. The recommended intake is 3.7 liters (appx. 1 gallon) per day for an adult male, and 2.7 liters (appx. 0.75 gallon) for an adult female. [18]

Other sources, however, claim that a high intake of fresh drinking water, separate and distinct from other sources of moisture, is necessary for good health – eight servings per day of eight fluid ounces (1.8 liters, or 0.5 gallon) is the amount recommended by many nutritionists, [19] although there is no scientific evidence supporting this recommendation. [20] [21]

Evidence-based hydration experts say that the amount of drinking water needed depends on ambient temperature, activity level, body size, and sweat rate. [22] Research shows drinking when thirsty will maintain hydration to within about 2% of the needed level. [22] Drinking beyond thirst might be beneficial for people who need to perform tasks that require intense concentration, and those with kidney disease, kidney stones, urinary tract infections, and people with a weak sense of thirst (which may include more older people). [22]

Alcoholic beverages

The term "drinking" is often used metonymically for the consumption of alcoholic beverages. Most cultures throughout history have incorporated some number of the wide variety of "strong drinks" into their meals, celebrations, ceremonies, toasts and other occasions. [23] Evidence of fermented drinks in human culture goes back as early as the Neolithic Period, [24] and the first pictorial evidence can be found in Egypt around 4,000 BC. [25]

Alcohol consumption has developed into a variety of well-established drinking cultures around the world. Despite its popularity, alcohol consumption poses significant health risks. Alcohol abuse and the addiction of alcoholism are common maladies in developed countries worldwide. [26] A high rate of consumption can also lead to cirrhosis, gastritis, gout, pancreatitis, hypertension, various forms of cancer, and numerous other illnesses. [27]

See also

Related Research Articles

<span class="mw-page-title-main">Stomach</span> Digestive organ

The stomach is a muscular, hollow organ in the upper gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is involved in the gastric phase of digestion, following the cephalic phase in which the sight and smell of food and the act of chewing are stimuli. In the stomach a chemical breakdown of food takes place by means of secreted digestive enzymes and gastric acid.

<span class="mw-page-title-main">Gastrointestinal tract</span> Organ system within humans and other animals

The gastrointestinal tract is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as faeces. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines.

<span class="mw-page-title-main">Dehydration</span> Deficit of total body water

In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mild dehydration can also be caused by immersion diuresis, which may increase risk of decompression sickness in divers.

<span class="mw-page-title-main">Peristalsis</span> Radially symmetrical contraction and relaxation of muscles

Peristalsis is a type of intestinal motility, characterized by radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which is preceded by a simultaneous contraction of the longitudinal muscle and relaxation of the circular muscle in the lining of the gut.

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.

<span class="mw-page-title-main">Esophagus</span> Vertebrate organ through which food passes to the stomach

The esophagus or oesophagus, colloquially known also as the food pipe, food tube, or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 cm (10 in) long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω + ἔφαγον.

Swallowing, also called deglutition or inglutition in scientific contexts, is the process in the body of a human or other animal that allows for a substance to pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. Swallowing is an important part of eating and drinking. If the process fails and the material goes through the trachea, then choking or pulmonary aspiration can occur. In the human body the automatic temporary closing of the epiglottis is controlled by the swallowing reflex.

<span class="mw-page-title-main">Eating</span> Ingestion of food

Eating is the ingestion of food. In biology, this is typically done to provide a heterotrophic organism with energy and nutrients and to allow for growth. Animals and other heterotrophs must eat in order to survive — carnivores eat other animals, herbivores eat plants, omnivores consume a mixture of both plant and animal matter, and detritivores eat detritus. Fungi digest organic matter outside their bodies as opposed to animals that digest their food inside their bodies.

<span class="mw-page-title-main">Thirst</span> Craving for potable fluids experienced by animals

Thirst is the craving for potable fluids, resulting in the basic instinct of animals to drink. It is an essential mechanism involved in fluid balance. It arises from a lack of fluids or an increase in the concentration of certain osmolites, such as sodium. If the water volume of the body falls below a certain threshold or the osmolite concentration becomes too high, structures in the brain detect changes in blood constituents and signal thirst.

<span class="mw-page-title-main">Chewing</span> Mechanical procedure for crushing the food and its first enzymatic splitting

Chewing or mastication is the process by which food is crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods.

<span class="mw-page-title-main">Licking</span> Action of passing the tongue over a surface

Licking is the action of passing the tongue over a surface, typically either to deposit saliva onto the surface, or to collect liquid, food or minerals onto the tongue for ingestion, or to communicate with other animals. Many animals both groom themselves, eat or drink by licking.

Cud is a portion of food that returns from a ruminant's stomach to the mouth to be chewed for the second time. More precisely, it is a bolus of semi-degraded food regurgitated from the reticulorumen of a ruminant. Cud is produced during the physical digestive process of rumination.

<span class="mw-page-title-main">Beer bong</span> Drinking device composed of a funnel and attached tube

A beer bong is a device composed of a funnel attached to a tube used to facilitate the rapid consumption of beer. The use of a beer bong is also known as funneling.

<span class="mw-page-title-main">Megaesophagus</span> Medical condition

Megaesophagus, also known as esophageal dilatation, is a disorder of the esophagus in humans and other mammals, whereby the esophagus becomes abnormally enlarged. Megaesophagus may be caused by any disease which causes the muscles of the esophagus to fail to properly propel food and liquid from the mouth into the stomach. Food can become lodged in the flaccid esophagus, where it may decay, be regurgitated, or maybe inhaled into the lungs.

<span class="mw-page-title-main">Cat anatomy</span> Anatomy of domesticated felines

Cat anatomy comprises the anatomical studies of the visible parts of the body of a domestic cat, which are similar to those of other members of the genus Felis.

Fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes in the various body fluids are kept within healthy ranges. The core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in; for example, in humans, the output must equal the input. Euvolemia is the state of normal body fluid volume, including blood volume, interstitial fluid volume, and intracellular fluid volume; hypovolemia and hypervolemia are imbalances. Water is necessary for all life on Earth. Humans can survive for 4 to 6 weeks without food but only for a few days without water.

The relationship between alcohol consumption and body weight is the subject of inconclusive studies. Findings of these studies range from increase in body weight to a small decrease among women who begin consuming alcohol. Some of these studies are conducted with numerous subjects; one involved nearly 8,000 and another 140,000 subjects.

Polydipsia is an excessively large water intake. Its occurrence in captive birds has been recorded, although it is a relatively rare abnormal behaviour.

<span class="mw-page-title-main">Human digestive system</span> Digestive system in humans

The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body. The process of digestion has three stages: the cephalic phase, the gastric phase, and the intestinal phase.

The rock dove, Columbia livia, has a number of special adaptations for regulating water uptake and loss.

References

  1. ↑ Flint, pp. 137–138.
  2. ↑ Mayer, p. 59.
  3. ↑ Grove JC, Gray LA, La Santa Medina N, Sivakumar N, Ahn JS, Corpuz TV, Berke JD, Kreitzer AC, Knight ZA (July 2022). "Dopamine subsystems that track internal states". Nature. 608 (7922): 374–380. Bibcode:2022Natur.608..374G. doi: 10.1038/s41586-022-04954-0 . PMC   9365689 . PMID   35831501.
  4. 1 2 3 4 5 6 7 8 Broom, p. 105.
  5. ↑ Smith, p. 238.
  6. ↑ "Cats' Tongues Employ Tricky Physics". 2010-11-12.
  7. ↑ Smith, p. 237.
  8. ↑ Mayer, p. 54.
  9. ↑ "How do Giraffes Drink Water?". February 2016.
  10. 1 2 3 Cade, Tom J.; Greenwald, Lewis I. (1966). "Drinking Behavior of Mousebirds in the Namib Desert, Southern Africa" (PDF). The Auk. 83 (1): 126–8. doi:10.2307/4082984. JSTOR   4082984.
  11. ↑ K. Lorenz, Verhandl. Deutsch. Zool. Ges., 41 [Zool. Anz. Suppl. 12]: 69–102, 1939
  12. ↑ Cade, Tom J.; Willoughby, Ernest J.; Maclean, Gordon L. (1966). "Drinking Behavior of Sandgrouse in the Namib and Kalahari Deserts, Africa" (PDF). The Auk. 83 (1): 124–6. doi:10.2307/4082983. JSTOR   4082983.
  13. ↑ Maclean, Gordon L. (1996). The Ecophysiology of Desert Birds. Springer. ISBN   3-540-59269-5.
  14. ↑ Elphick, Jonathan (2016). Birds: A Complete Guide to their Biology and Behavior. Buffalo, New York: Firefly Books. pp. 53–54. ISBN   978-1-77085-762-9.
  15. 1 2 3 Chapman, R. F. (2012). Simpson, S. J.; Douglas, A. E. (eds.). The Insects: Structure and Function (5 ed.). Cambridge University Press. p. 577. ISBN   978-1107310452.
  16. 1 2 Curtis, p. 569.
  17. ↑ Provan, p. 129.
  18. ↑ Institute of Medicine (2005). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: The National Academies Press. p. 73. ISBN   978-0-309-13335-7.
  19. ↑ Greenhalgh, Alison (2001). "Healthy living – Water". BBC Health. BBC. Archived from the original on 8 April 2013. Retrieved 1 January 2022.
  20. ↑ Valtin, Heinz; Gorman, Sheila A. (2012). "Drink at least eight glasses of water a day: Really? Is there scientific evidence for "8 × 8"?". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology. 283 (5): R993–R1004. doi:10.1152/ajpregu.00365.2002. PMID   12376390.
  21. ↑ Negoianu, Dan; Goldfarb, Stanley (2008). "Just Add Water". Journal of the American Society of Nephrology. 19 (6). ASN: 1041–1043. doi: 10.1681/ASN.2008030274 . PMID   18385417.
  22. 1 2 3 How much water do you actually need? Here's the science
  23. ↑ Gately, pp. 1–14.
  24. ↑ Patrick, Clarence Hodges. Alcohol, Culture, and Society. AMS Press, 1952, p. 13.
  25. ↑ Hanson, David. "Ancient Period". History of Alcohol and Drinking around the World. State University of New York. Archived from the original on 19 February 2014. Retrieved 4 December 2014.
  26. ↑ "Global Status Report on Alcohol and Health" (PDF). World Health Organization. Retrieved 4 December 2014.
  27. ↑ Fiebach, p. 387.

Bibliography

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