Tubercle

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This view of the cactus Mammillaria marksiana shows its pattern of prominent tubercles, with the spines emanating from each tubercle's tip. Mammillaria marksiana.jpg
This view of the cactus Mammillaria marksiana shows its pattern of prominent tubercles, with the spines emanating from each tubercle's tip.

In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal.

Contents

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 orchids and cacti, it denotes a round nodule, small eminence, or warty 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

In mycology, a tubercle is used to refer to a mass of hyphae from which a mushroom is made.

In animals

Nudibranch Phyllidia varicosa, clearly showing the yellow tubercles on the dorsum Phyllidia.jpg
Nudibranch Phyllidia varicosa , clearly showing the yellow tubercles on the dorsum

When it is used in relation to certain dorid nudibranchs 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 whales' flippers were demonstrated to improve fluid flow over the flipper's surface, exhibiting the tubercle effect of fluid dynamics. [1]

Skin impression from the abdomen of the duck-billed dinosaur Edmontosaurus annectens, showing tubercular scales Edmontosaurusskin.jpg
Skin impression from the abdomen of the duck-billed dinosaur Edmontosaurus annectens , showing tubercular scales

In dinosaurs, 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, polygonal tubercles (pavement tubercles) up to 1 cm (0.39 in) in diameter, which are grouped into clusters separated by ground tubercles; and limpet-shaped conical scutes. [2]

In fish, nuptial tubercles are formed on males for breeding. Nuptial pads on frogs also comprise keratinised 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 gum. Surgery can be done to make tubercles less prominent. [3]

Bones

In the human skeleton, a tubercle or tuberosity is a protrusion that serves as an attachment for skeletal muscles. The muscles attach by tendons, where the enthesis is the connective tissue between the tendon and bone. [4] For example, the tibial tuberosity creates an attachment point for the ligamentum patellae, 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. Granulomas form in the infected tissue and undergo necrosis 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 His, [lower-alpha 1] arise around the area that will form the ear canal. [6] 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. [7]

Genitals

The genital tubercle is a small bump that eventually develops into a 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.[ citation needed ]

Also, the tuberculum sellae is found at the base of the skull, which holds the hypophysis.

See also

Notes

  1. Named after Wilhelm His Sr. who first described them in 1855. [5]

Related Research Articles

Spicules are any of various small needle-like anatomical structures occurring in organisms

<span class="mw-page-title-main">Scapula</span> Bone that connects the humerus (upper arm bone) with the clavicle (collar bone)

The scapula, also known as the shoulder blade, is the bone that connects the humerus with the clavicle. Like their connected bones, the scapulae are paired, with each scapula on either side of the body being roughly a mirror image of the other. The name derives from the Classical Latin word for trowel or small shovel, which it was thought to resemble.

<span class="mw-page-title-main">Humerus</span> Long bone of the upper arm

The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.

<span class="mw-page-title-main">Biceps</span> Muscle on the front of the upper arm

The biceps or biceps brachii are a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. While the biceps crosses both the shoulder and elbow joints, its main function is at the elbow where it flexes the forearm and supinates the forearm. Both these movements are used when opening a bottle with a corkscrew: first biceps screws in the cork (supination), then it pulls the cork out (flexion).

<span class="mw-page-title-main">Cuboid bone</span> Bone of the ankle

In the human body, the cuboid bone is one of the seven tarsal bones of the foot.

<span class="mw-page-title-main">Tibia</span> Leg bone in vertebrates

The tibia, also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates ; it connects the knee with the ankle. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane. The tibia is connected to the fibula by the interosseous membrane of leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute tibia. It is the second largest bone in the human body, after the femur. The leg bones are the strongest long bones as they support the rest of the body.

<span class="mw-page-title-main">Calcaneus</span> Bone of the tarsus of the foot

In humans and many other primates, the calcaneus or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock.

<span class="mw-page-title-main">Radius (bone)</span> One of the two long bones of the forearm

The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, prism-shaped and slightly curved longitudinally.

<span class="mw-page-title-main">Ear</span> Organ of hearing and balance

An ear is the organ that enables hearing and 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 of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ear canal is cleaned via earwax, which naturally migrates to the auricle. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localization.

<span class="mw-page-title-main">Auricle (anatomy)</span> Visible part of the ear that is outside the head

The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna, a term that is used more in zoology.

<span class="mw-page-title-main">Process (anatomy)</span> Projection or outgrowth of tissue from a larger body

In anatomy, a process is a projection or outgrowth of tissue from a larger body. For instance, in a vertebra, a process may serve for muscle attachment and leverage, or to fit, with another vertebra. The word is also used at the microanatomic level, where cells can have processes such as cilia or pedicels. Depending on the tissue, processes may also be called by other terms, such as apophysis, tubercle, or protuberance.

<span class="mw-page-title-main">Subscapularis muscle</span> Large triangle muscle of the shoulder

The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.

<span class="mw-page-title-main">Adductor magnus muscle</span> Muscle in the thigh

The adductor magnus is a large triangular muscle, situated on the medial side of the thigh.

<span class="mw-page-title-main">Fibularis brevis</span> Shorter and smaller of the fibularis (peroneus) muscles

In human anatomy, the fibularis brevis is a muscle that lies underneath the fibularis longus within the lateral compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to extend the foot downward away from the body at the ankle.

<span class="mw-page-title-main">Dog anatomy</span> Studies of the visible part of a canine

Dog anatomy comprises the anatomical study of the visible parts of the body of a domestic dog. Details of structures vary tremendously from breed to breed, more than in any other animal species, wild or domesticated, as dogs are highly variable in height and weight. The smallest known adult dog was a Yorkshire Terrier that stood only 6.3 cm (2.5 in) at the shoulder, 9.5 cm (3.7 in) in length along the head and body, and weighed only 113 grams (4.0 oz). The heaviest dog was an English Mastiff named Zorba, which weighed 314 pounds (142 kg). The tallest known adult dog is a Great Dane that stands 106.7 cm (42.0 in) at the shoulder.

<span class="mw-page-title-main">Ischium</span> Lower and back region of the hip bone

The ischium forms the lower and back region of the hip bone.

<span class="mw-page-title-main">Pubis (bone)</span> Most forward-facing of the three main regions making up the os coxa

In vertebrates, the pubis or pubic bone forms the lower and anterior part of each side of the hip bone. The pubis is the most forward-facing of the three bones that make up the hip bone. The left and right pubic bones are each made up of three sections; a superior ramus, an inferior ramus, and a body.

<span class="mw-page-title-main">Condyloid process</span>

The condyloid process or condylar process is the process on the human and other mammalian species' mandibles that ends in a condyle, the mandibular condyle. It is thicker than the coronoid process of the mandible and consists of two portions: the condyle and the constricted portion which supports it, the neck.

<span class="mw-page-title-main">Anatomical terms of bone</span>

Many anatomical terms descriptive of bone are defined in anatomical terminology, and are often derived from Greek and Latin. Bone in the human body is categorized into long bone, short bone, flat bone, irregular bone and sesamoid bone.

In the skeleton of humans and other animals, a tubercle, tuberosity or apophysis is a protrusion or eminence that serves as an attachment for skeletal muscles. The muscles attach by tendons, where the enthesis is the connective tissue between the tendon and bone. A tuberosity is generally a larger tubercle.

References

  1. Miklosovic, D. S.; Murray, M. M.; Howle, L. E.; Fish, F. E. (2004). "Leading-edge tubercles delay stall on humpback whale ( Megaptera novaeangliae ) flippers". Physics of Fluids. 16 (5): L39–L42. Bibcode:2004PhFl...16L..39M. doi:10.1063/1.1688341.
  2. Lull, Richard Swann; Wright, Nelda E. (1942). Hadrosaurian Dinosaurs of North America. Geological Society of America Special Paper. Vol. 40. Geological Society of America. pp. 111–112.
  3. "What is Tuberosity Reduction?", Colgate World of Care
  4. "enthesis". Medcyclopaedia. GE. Archived from the original on 2012-02-05.
  5. Davis, Jack (1997). Otoplasty. Springer, p. 24. ISBN   978-1-4612-7484-1
  6. Anthwal, Neal; Thompson, Hannah (February 2016). "The development of the mammalian outer and middle ear". Journal of Anatomy. 228 (2): 217–232. doi:10.1111/joa.12344.
  7. Laura Spinney (19 May 2008). "Five things humans no longer need". NewScientist.com news service. Archived from the original on 24 July 2008.