anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or

wart Warts are typically small, rough, hard growths that are similar in color to the rest of the skin. They typically do not result in other symptoms, except when on the bottom of the feet, where they may be painful. While they usually occur on the ...

y outgrowth found on external or internal organs of a plant or an animal.

In plants

A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to. In the case of certain

orchid Orchids are plants that belong to the Family (biology), family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest fam ...

s and

cacti A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Gre ...

, it denotes a round nodule, small eminence, or

y outgrowth found on the lip. They are also known as podaria (singular ''podarium''). When referring to some members of the pea family, it is used to refer to the wart-like excrescences that are found on the roots.

In fungi

mycology Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans, including as a source for tinder, traditional medicine, food, and entheogens, as ...

, a tubercle is used to refer to a mass of

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e from which a

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

is made.

In animals

When it is used in relation to certain dorid

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match ...

s such as '' Peltodoris nobilis'', it means the nodules on the dorsum of the animal. The tubercles in nudibranchs can present themselves in different ways: each tubercle in a single, rounded, conical or angular form, in a compound form of 2 or more levels, tubercles in amalgamated clusters or as tubercles forming, or joined by a ridge. Tubercles found on the leading edge of

humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hump ...

's flippers were demonstrated to improve fluid flow over the flipper's surface, exhibiting the

tubercle effect The tubercle effect is a phenomenon where tubercles or large 'bumps' on the leading edge of an airfoil can improve its aerodynamics. The effect, while already discovered, was analyzed extensively by Frank E. Fish et al in the early 2000 onwards ...

of fluid dynamics. Edmontosaurusskin

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is ...

s, a tubercle is a general term for the scales seen in skin impressions. In duck-billed dinosaurs, for example, three main types of tubercles are defined: small tubercles with no definite arrangement (ground tubercles); larger,

polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed '' polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two t ...

al tubercles (pavement tubercles) up to 1 cm (0.4 in) in diameter, which are grouped into clusters separated by ground tubercles; and

limpet Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" descended indep ...

-shaped conical scutes.

In humans

Within the human body, there are numerous sites where tubercles develop. On bones, they are usually eminences used for

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of m ...

connections. Larger tubercles are also known as ''tuberosities''.

Mouth

Tubercles are usually found behind the last molar in the upper jaw, covered by the

gum Gum may refer to: Types of gum * Adhesive * Bubble gum * Chewing gum * Gum (botany), sap or other resinous material associated with certain species of the plant kingdom ** Gum arabic, made from the sap of '' Acacia senegal'', an Old World tree ...

. Surgery can be done to make tubercles less prominent.

Bones

In the

human skeleton The human skeleton is the internal framework of the human body. It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. The bone mass in the skeleton makes up a ...

, a ''tubercle'' or ''tuberosity'' is a protrusion that serves as an attachment for

skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of mus ...

s. The muscles attach by

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its abilit ...

s, where the

enthesis The enthesis (plural entheses) is the connective tissue between tendon or ligament and bone. There are two types of entheses: ''Fibrous entheses'' and ''fibrocartilaginous entheses''. In a fibrous enthesis, the collagenous tendon or ligament dire ...

is the connective tissue between the tendon and

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...

. For example, the tibial tuberosity creates an attachment point for the ligamentum patellae, or patellar ligament.

Lungs

Tubercles are nodules that contain

caseous necrosis Caseous necrosis or caseous degeneration () is a unique form of cell death in which the tissue maintains a cheese-like appearance.Robbins and Cotran: Pathologic Basis of Disease, 8th Ed. 2010. Pg. 16 It is also a distinctive form of coagulative nec ...

, which form in the lungs as a result of an infection with ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on i ...

'' in the patients with

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...

Granuloma A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious ...

s form in the infected tissue and undergo

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dig ...

in the centre. Tubercles are also known as tuberculous nodules, or tuberculomas. The affected parts develop lesions in the form of small nodules called tubercles, from which the disease gets its name.

Ears

Around the sixth week of gestation, six swellings of tissue called the ''hillocks of Hiss'' arise around the area that will form the

ear An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists ...

canal. These eventually coalesce to form the outer ear. Darwin's tubercle is a minor malformation of the junction of the fourth and fifth hillocks of Hiss. It is found in a substantial minority of people and takes the form of a cartilaginous node or bump on the rim of their outer ear, which is thought to be the vestige of a joint that allowed the top part of the ancestral ear to swivel or flop down over the opening to the ear.

Genitals

The

genital tubercle A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In t ...

is a small bump that eventually develops into a

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...

or a

clitoris The clitoris ( or ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible portion – the glans – is at the front junction of the labia minora (inner lips), above the o ...

on a human

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal devel ...

Brain

The septotubercular tract can be found in the human, as well as in the sheep brain. It is found nearby the septohypothalamic tract. Its function to the brain is ambiguous at this point. Also, the tuberculum sellae is found at the base of the skull, which holds the hypophysis.

References

External links

Tubercle at Cactus-Art.biz
{{Authority control Human anatomy Animal anatomy Plant morphology