In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small , or 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 and cactus, it denotes a round nodule, small , or outgrowth found on the lip. They are also known as podaria (singular podarium). When referring to some members of the Fabaceae, it is used to refer to the wart-like excrescences that are found on the roots.
In fungi
In
mycology, a tubercle is used to refer to a mass of
from which a
mushroom is made.
In animals
When it is used in relation to certain dorid
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 two or more levels; tubercles in amalgamated clusters; or as tubercles forming, or joined by a ridge.
Tubercles found on the leading edge of ' flippers were demonstrated to improve fluid flow over the flipper's surface, exhibiting the tubercle effect of fluid dynamics.
In , a tubercle is a general term for the scales seen in skin impressions. In hadrosaurid, for example, three main types of tubercles are defined: small tubercles with no definite arrangement (ground tubercles); larger, tubercles (pavement tubercles) up to in diameter, which are grouped into clusters separated by ground tubercles; and limpet-shaped conical scutes.
In fish, nuptial tubercles are formed on males for breeding. Nuptial pads on frogs also comprise tubercles.
In humans
Within the human body, there are numerous sites where tubercles develop. On bones, they are usually eminences used for
muscle connections. Larger tubercles are also known as
tuberosities.
Mouth
Tubercles are usually found behind the last molar in the upper jaw, covered by the
Gingiva. Surgery can be done to make tubercles less prominent.
[ "What is Tuberosity Reduction?", Colgate World of Care]
Bones
In the
human skeleton, a
tubercle or
tuberosity is a protrusion that serves as an attachment for
. The muscles attach by
, where the
enthesis is the connective tissue between the tendon and
bone.
For example, the tibial tuberosity creates an attachment point for the
knee, or patellar ligament.
Lungs
Tubercles are nodules that contain
caseous necrosis, which form in the lungs as a result of an infection with
Mycobacterium tuberculosis in the patients with
tuberculosis.
form in the infected tissue and undergo
necrosis in the centre. Tubercles are also known as tuberculous nodules, or
. 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 His, arise around the area that will form the
ear 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 His. 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 is a small bump that eventually develops into a
Human penis or a
clitoris on a human
fetus.
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 Pituitary gland.
See also
Notes
External links
