Branchiostegal lung

Last updated

A branchiostegal lung is a respiration organ used by some air-breathing arthropods. It is one of the most significant adaptations of some crabs [1] and hermit crabs such as the coconut crab to their terrestrial habitats.

The branchiostegal (gill) tissue is supported by folds or other mechanisms to increase surface area and are of a similar tissue to that normally found in gills. In this case, the lung is more suited to the absorption of oxygen from air, rather than water.

Instead of branchiostegal lungs, some terrestrial hermit crabs ( Coenobita ) possess multiple gills and small lungs, with other varieties of gas diffusion methods supporting the transition from aquatic to terrestrial dwelling.

The developmental shift from water diffusion "gills" to air perfusion "lungs" may have been related to the need for reduced rates of water loss in air.

Related Research Articles

<span class="mw-page-title-main">Lung</span> Primary organ of the respiratory system

The lungs are the most important organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the air and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. The pleurae, which are thin, smooth, and moist, serve to reduce friction between the lungs and chest wall during breathing, allowing for easy and effortless movements of the lungs.

<span class="mw-page-title-main">Gill</span> Respiratory organ used by aquatic organisms

A gill is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia is the zoologists' name for gills.

<span class="mw-page-title-main">Respiratory system</span> Biological system in animals and plants for gas exchange

The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals, the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs; in mammals and reptiles, these are called alveoli, and in birds, they are known as atria. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds, the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.

<span class="mw-page-title-main">Book lung</span> Type of lung commonly found in arachnids

A book lung is a type of respiration organ used for atmospheric gas exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open ventral abdominal, air-filled cavity (atrium) and connects with its surroundings through a small opening for the purpose of respiration.

<span class="mw-page-title-main">Hermit crab</span> Superfamily of crustaceans (Paguroidea)

Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless.

<span class="mw-page-title-main">Aquatic respiration</span> Process whereby an aquatic animal obtains oxygen from water

Aquatic respiration is the process whereby an aquatic organism exchanges respiratory gases with water, obtaining oxygen from oxygen dissolved in water and excreting carbon dioxide and some other metabolic waste products into the water.

<span class="mw-page-title-main">Gas exchange</span> Process by which gases diffuse through a biological membrane

Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.

In physiology, respiration is the movement of oxygen from the outside environment to the cells within tissues, and the removal of carbon dioxide in the opposite direction that's to the environment.

<span class="mw-page-title-main">Caribbean hermit crab</span> Species of crustacean

The Caribbean hermit crab, also known as the soldier crab, West Atlantic crab, tree crab, or purple pincher, is a species of land hermit crab native to the west Atlantic, Belize, southern Florida, Venezuela, and the West Indies.

<span class="mw-page-title-main">Hypoxemia</span> Abnormally low level of oxygen in the blood

Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the body.

<span class="mw-page-title-main">Amphibious fish</span>

Amphibious fish are fish that are able to leave water for extended periods of time. About 11 distantly related genera of fish are considered amphibious. This suggests that many fish genera independently evolved amphibious traits, a process known as convergent evolution. These fish use a range of terrestrial locomotory modes, such as lateral undulation, tripod-like walking, and jumping. Many of these locomotory modes incorporate multiple combinations of pectoral-, pelvic-, and tail-fin movement.

<span class="mw-page-title-main">Terrestrial animal</span> Animals living on land

Terrestrial animals are animals that live predominantly or entirely on land, as compared with aquatic animals, which live predominantly or entirely in the water, and amphibians, which rely on aquatic and terrestrial habitats. Some groups of insects are terrestrial, such as ants, butterflies, earwigs, cockroaches, grasshoppers and many others, while other groups are partially aquatic, such as mosquitoes and dragonflies, which pass their larval stages in water.

<span class="mw-page-title-main">Sea snail</span> Common name for snails that normally live in saltwater

Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible shell.

<i>Coenobita brevimanus</i> Species of crustacean

Coenobita brevimanus is a species of terrestrial hermit crab belonging to the family Coenobitidae, which is composed of coastal living terrestrial hermit crabs. From there it belongs to the genus Coenobita, one of two genera split from the family, which contains sixteen species. The Latin origins of the species name, brevimanus, come from the adjective brevis ("small") and the noun manus ("hands"). It is known as the Indos crab or Indonesian crab because it is primarily distributed throughout the Indo-Pacific.

<span class="mw-page-title-main">Coconut crab</span> Species of crustacean

The coconut crab is a terrestrial species of giant hermit crab, and is also known as the robber crab or palm thief. It is the largest terrestrial arthropod known, with a weight of up to 4.1 kg (9 lb). The distance from the tip of one leg to the tip of another can be as wide as 1 m. It is found on islands across the Indian and Pacific Oceans, as far east as the Gambier Islands, Pitcairn Islands and Caroline Island and as far south as Zanzibar. While its range broadly shadows the distribution of the coconut palm, the coconut crab has been extirpated from most areas with a significant human population such as mainland Australia and Madagascar.

A breathing tube is a hollow component that can serve as a conduit for breathing. Various types of breathing tubes are available for different specific applications. Many of them are generally known by more specific terms.

<span class="mw-page-title-main">Fish gill</span> Organ that allows fish to breathe underwater

Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills that are protected under gill covers (operculum) on both sides of the pharynx (throat). Gills are tissues that are like short threads, protein structures called filaments. These filaments have many functions including the transfer of ions and water, as well as the exchange of oxygen, carbon dioxide, acids and ammonia. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide.

Work of breathing (WOB) is the energy expended to inhale and exhale a breathing gas. It is usually expressed as work per unit volume, for example, joules/litre, or as a work rate (power), such as joules/min or equivalent units, as it is not particularly useful without a reference to volume or time. It can be calculated in terms of the pulmonary pressure multiplied by the change in pulmonary volume, or in terms of the oxygen consumption attributable to breathing.

<span class="mw-page-title-main">Physiology of decompression</span> The physiological basis for decompression theory and practice

The physiology of decompression is the aspect of physiology which is affected by exposure to large changes in ambient pressure, and involves a complex interaction of gas solubility, partial pressures and concentration gradients, diffusion, bulk transport and bubble mechanics in living tissues. Gas is breathed at ambient pressure, and some of this gas dissolves into the blood and other fluids. Inert gas continues to be taken up until the gas dissolved in the tissues is in a state of equilibrium with the gas in the lungs,, or the ambient pressure is reduced until the inert gases dissolved in the tissues are at a higher concentration than the equilibrium state, and start diffusing out again.

Human physiology of underwater diving is the physiological influences of the underwater environment on the human diver, and adaptations to operating underwater, both during breath-hold dives and while breathing at ambient pressure from a suitable breathing gas supply. It, therefore, includes the range of physiological effects generally limited to human ambient pressure divers either freediving or using underwater breathing apparatus. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, the effects of breathing gases at raised ambient pressure, effects caused by the use of breathing apparatus, and sensory impairment. All of these may affect diver performance and safety.

References

  1. Halperin J, Ansaldo M, Pellerano GN, Luquet CM (2000). "Bimodal breathing in the estuarine crab Chasmagnathus granulatus Dana 1851 — physiological and morphological studies". Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology . 126 (3): 341–349. doi:10.1016/S1095-6433(00)00216-6. PMID   10964029.