Crop (anatomy)

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Two white-bellied parrots with bulging crops after feeding. Pionites leucogaster -Zoologico de Sao Paulo -Brazil-6a.jpg
Two white-bellied parrots with bulging crops after feeding.
A graylag goose eats grass, the full crop is clearly visible.
One greater flamingo-chick in Zoo Basel is fed on crop milk. Rosaflamingo-Kuken - Fuetterung mit Kropfmilch.jpg
One greater flamingo-chick in Zoo Basel is fed on crop milk.
The crop (serial 4) of a pigeon (Columba livia) is prominently seen at the beginning of the alimentary canal. PigeonAnatomy.png
The crop (serial 4) of a pigeon (Columba livia) is prominently seen at the beginning of the alimentary canal.

The crop (also the croup, the craw, the ingluvies, and the sublingual pouch) is a thin-walled, expanded portion of the alimentary tract, which is used for the storage of food before digestion. The gizzard is an anatomical structure in vertebrate animals, such as birds, and invertebrate animals, such as gastropods (snails and slugs), earthworms, [1] leeches, [2] and insects. [3]

Contents

Insects

Cropping is used by bees to temporarily store nectar of flowers. When bees "suck" nectar, it is stored in their crops. [4] Other Hymenoptera also use crops to store liquid food. The crop in eusocial insects, such as ants, has specialized to be distensible, and this specialization enables important communication between colonial insects through trophallaxis. [5] The crop can be found in the foregut of insects. [6]

Birds

In a bird's digestive system, the crop is an expanded, muscular pouch near the gullet or throat. It is a part of the digestive tract, essentially an enlarged part of the esophagus. As with most other organisms that have a crop, it is used to temporarily store food. Not all bird species have one. In adult doves and pigeons, it can produce crop milk to feed newly hatched birds. [7]

Scavenging birds, such as vultures, will gorge themselves when prey is abundant, causing their crop to bulge. They subsequently sit, sleepy or half torpid, to digest their food.

Most raptors, including hawks, eagles and vultures (as stated above), have a crop; however, owls do not. Similarly, all true quail (Old World quail and New World quail) have a crop, but buttonquail do not. Chickens, turkeys, ducks [8] and geese [9] possess a crop, as do parrots. [10] Pigeons also have crops; one domestic breed type is even bred to exaggerate the typical crop-inflating behavior so that the crop is inflated like a balloon.

Some extinct birds like Enantiornithes did not have crops. [11]

Literary references

In the Sherlock Holmes story "The Adventure of the Blue Carbuncle" (1892), a valuable gem is hidden inside a bird's crop. [12]

"Craw" is an obsolete term for "crop", [13] and this is still seen in the saying "it sticks in my craw" meaning "I can't [metaphorically] swallow it", that is, that a situation or other entity is unacceptable, or at any rate annoying. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Digestion</span> Biological process of breaking down food

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">Eating</span> Ingestion of food

Eating is the ingestion of food. In the natural biological world, this is typically 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">Trophallaxis</span> Transfer of food between members of a community through stomodeal or proctodeal means

Trophallaxis is the transfer of food or other fluids among members of a community through mouth-to-mouth (stomodeal) or anus-to-mouth (proctodeal) feeding. Along with nutrients, trophallaxis can involve the transfer of molecules such as pheromones, organisms such as symbionts, and information to serve as a form of communication. Trophallaxis is used by some birds, gray wolves, vampire bats, and is most highly developed in eusocial insects such as ants, wasps, bees, and termites.

<span class="mw-page-title-main">Gizzard</span> Digestive organ of some animals

The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including archosaurs, earthworms, some gastropods, some fish, and some crustaceans. This specialized stomach constructed of thick muscular walls is used for grinding up food, often aided by particles of stone or grit. In certain insects and molluscs, the gizzard features chitinous plates or teeth.

<i>Eclectus</i> Genus of birds

Eclectus is a genus of parrot, the Psittaciformes, which consists of four known extant species known as eclectus parrots and the extinct Eclectus infectus, the oceanic eclectus parrot. The extant eclectus parrots are medium-sized parrots native to regions of Oceania, particularly New Guinea and Australia. Males are mostly bright green, females are predominantly bright red. The male and female eclectus were once thought to be different species. The conservation status of the remaining species is least concern. Eclectus parrots do well in captivity, and are a very popular pet across the world.

Extracellular phototropic digestion is a process in which saprobionts feed by secreting enzymes through the cell membrane onto the food. The enzymes catalyze the digestion of the food ie diffusion, transport, osmotrophy or phagocytosis. Since digestion occurs outside the cell, it is said to be extracellular. It takes place either in the lumen of the digestive system, in a gastric cavity or other digestive organ, or completely outside the body. During extracellular digestion, food is broken down outside the cell either mechanically or with acid by special molecules called enzymes. Then the newly broken down nutrients can be absorbed by the cells nearby. Humans use extracellular digestion when they eat. Their teeth grind the food up, enzymes and acid in the stomach liquefy it, and additional enzymes in the small intestine break the food down into parts their cells can use. Extracellular digestion is a form of digestion found in all saprobiontic annelids, crustaceans, arthropods, lichens and chordates, including vertebrates.

<span class="mw-page-title-main">Bird intelligence</span> Study of intelligence in birds

The difficulty of defining or measuring intelligence in non-human animals makes the subject difficult to study scientifically in birds. In general, birds have relatively large brains compared to their head size. The visual and auditory senses are well developed in most species, though the tactile and olfactory senses are well realized only in a few groups. Birds communicate using visual signals as well as through the use of calls and song. The testing of intelligence in birds is therefore usually based on studying responses to sensory stimuli.

Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly. The development of a beak has led to evolution of a specially adapted digestive system.

<span class="mw-page-title-main">Mouth</span> First portion of the alimentary canal that receives food

The mouth is the body orifice through which many animals ingest food and vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity, is also the first part of the alimentary canal which leads to the pharynx and the gullet. In tetrapod vertebrates, the mouth is bounded on the outside by the lips and cheeks — thus the oral cavity is also known as the buccal cavity — and contains the tongue on the inside. Except for some groups like birds and lissamphibians, vertebrates usually have teeth in their mouths, although some fish species have pharyngeal teeth instead of oral teeth.

The proventriculus is part of the digestive system of birds. An analogous organ exists in invertebrates and insects.

<span class="mw-page-title-main">Earthworm</span> Terrestrial invertebrate, order Opisthopora

An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class Oligochaeta. In classical systems, they were in the order of Opisthopora since the male pores opened posterior to the female pores, although the internal male segments are anterior to the female. Theoretical cladistic studies have placed them in the suborder Lumbricina of the order Haplotaxida, but this may change. Other slang names for earthworms include "dew-worm", "rainworm", "nightcrawler", and "angleworm". Larger terrestrial earthworms are also called megadriles as opposed to the microdriles in the semiaquatic families Tubificidae, Lumbricidae and Enchytraeidae. The megadriles are characterized by a distinct clitellum and a vascular system with true capillaries.

<span class="mw-page-title-main">Pharynx</span> Part of the throat that is behind the mouth and nasal cavity

The pharynx is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea. It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx. The flap of cartilage called the epiglottis stops food from entering the larynx.

<span class="mw-page-title-main">Digestive system of gastropods</span>

The digestive system of gastropods has evolved to suit almost every kind of diet and feeding behavior. Gastropods as the largest taxonomic class of the mollusca are very diverse: the group includes carnivores, herbivores, scavengers, filter feeders, and even parasites.

<i>Trichomonas gallinae</i> Species of bird parasite

Trichomonas gallinae is a cosmopolitan parasite of birds including finches, pigeons, doves, turkeys, chickens, parrots, raptors. The condition in birds of prey is called frounce. It is believed to be an ancient pathogen causing frounce-like symptoms in theropod dinosaurs. The same condition in pigeons is commonly called canker.

<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.

References

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  2. Sawyer, Roy T. "Leech Biology and Behaviour, Volume II" (PDF). Retrieved 2014-01-09.
  3. Triplehorn, Charles A; Johnson, Norman F (2005). Borror and DeLong's introduction to the study of insects (7th ed.). Australia: Thomson, Brooks/Cole. ISBN   9780030968358.
  4. "Honeybee Biology". 1994. Retrieved 2008-12-16.
  5. Leboeuf, Adria C.; Waridel, Patrice; Brent, Colin S.; Gonçalves, Andre N.; Menin, Laure; Ortiz, Daniel; Riba-Grognuz, Oksana; Koto, Akiko; Soares, Zamira G.; Privman, Eyal; Miska, Eric A.; Benton, Richard; Keller, Laurent (2019). "Oral transfer of chemical cues, growth proteins and hormones in social insects". eLife. 5. doi: 10.7554/eLife.20375 . PMC   5153251 . PMID   27894417.
  6. Sal, Lorrianne K. (12 February 2017). "Digestion: An imperative process for insects".
  7. Gordon John Larkman Ramel (2008-09-29). "The Alimentary Canal in Birds" . Retrieved 2008-12-16.
  8. Jalaludeen, A.; Churchil, R. Richard; Baéza, Elisabeth, eds. (2022). Duck Production and Management Strategies. doi:10.1007/978-981-16-6100-6. ISBN   978-981-16-6099-3. S2CID   246040130.
  9. "Chapter 3. DIGESTIVE PHYSIOLOGY".
  10. Grindol, Diane (12 December 2013). "Five Pet Parrot Facts". Lafeber Company. Retrieved 6 November 2021.
  11. O'Connor, Jingmai K.; Zhou, Zhonghe (2020). "The evolution of the modern avian digestive system: Insights from paravian fossils from the Yanliao and Jehol biotas". Palaeontology. 63 (1): 13–27. Bibcode:2020Palgy..63...13O. doi:10.1111/pala.12453. S2CID   210265348.
  12. Alfred Hickling. "Review: The New Annotated Sherlock Holmes edited by Leslie S Klinger | Books". The Guardian. Retrieved 2012-07-26.
  13. "craw". Merriam-Webster Dictionary. Retrieved July 6, 2023.
  14. "stick in your craw". Macmillan Dictionary. Retrieved August 15, 2021.