Vibrissae

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Vibrissae

Vibrissae (singular: vibrissa), or whiskers, are specialized hair

Hair

Hair is a protein filament that epidermal growth from hair follicle deep within the dermis. The fine, soft hair found on many nonhuman mammals is typically called fur; wool is the characteristically curly hair found on sheep and goats....
s, usually employed for tactile sensation, but can also refer to the stiff feather

Feather

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. They are considered the most complex integumentary structures found in vertebrates....
s near the mouths of some bird

Bird

Birds are wing, Bipedalismal, endothermic , vertebrate animals that lay egg . There are around 10,000 living species, making them the most numerous tetrapod vertebrates....
s.

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Vibrissae (singular: vibrissa), or whiskers, are specialized hair

Hair

Feather

Bird

Birds are wing, Bipedalismal, endothermic , vertebrate animals that lay egg . There are around 10,000 living species, making them the most numerous tetrapod vertebrates....
s. Vibrissae hairs commonly grow around the nostril

Nostril

A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation....
s, above the lips, and on other parts of the face of most mammal

Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
s, as well as on the forelegs and feet of some animals. Vibrissae are usually thicker and stiffer than other types of hair. It may also refer to the thick hairs found inside human

Human

A human being, also human or man, is a member of a species of bipedalism primates in the family Hominidae . Mitochondrial DNA evidence indicates that modern humans originated in east Africa about 200,000 years ago....
nostrils, in this case they have no sensorial function, but operate as a barrier to particles.

Vibrissae consist of inert material and contain no nerve

Nerve

A nerve is an enclosed, cable-like bundle of Peripheral nervous system axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons....
s, but do have special sensory cells associated with them. Vibrissae are different from other hairs mainly because they are implanted in a special follicle

Hair follicle

A hair follicle is part of the skin that grows hair by packing old Cell s together. Attached to the follicle is a sebaceous gland, a tiny sebum-producing gland found everywhere except on the hands, lips and soles of the feet....
sealed by a capsule

Capsule (anatomy)

A capsule, in anatomy, is a cover or envelope partly or wholly surrounding a structure. Types of capsules include:* the shell of an egg * joint capsules - every synovial joint possesses a fibrous or ligamentous capsule, lined with synovial membrane, attached to the adjacent ends of the articulating bones...
of blood

Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's Cell s ? such as nutrients and oxygen ? and transports waste products away from those same cells....
, called a blood sinus

Sinus (anatomy)

Sinus is Latin for "bay", "pocket", "curve", or "bosom". In anatomy, the term is used in various contexts.A sinus is a sack or cavity in any organ or biological tissue, or an abnormal cavity or passage caused by the destruction of tissue....
. Touching a vibrissa causes it to bend, and the blood in the sinus is pushed to one side or the other. The blood amplifies the movement and allows the mechanoreceptor

Mechanoreceptor

A mechanoreceptor is a sensory receptor that responds to mechanical pressure or distortion. There are four main types in the glabrous skin of humans: Pacinian corpuscles, Meissner's corpuscles, Merkel nerve ending, and Ruffini corpuscles....
s at the base of the vibrissa to detect extremely small deflections.

In some mammals, the follicles of vibrissae are surrounded by a highly developed sheath of muscle

MUSCLE

MUSCLE is public domain, multiple sequence alignment software for protein and nucleotide sequences.MUSCLE is integrated into UGENE bioinformatics tool as a plugin....
tissue which can be used to move them, such as in the case of whiskers found on cats, dogs and other mammals. Whiskers can grow to be extremely long; the length of a chinchilla

Chinchilla

Chinchillas are crepuscular rodents, slightly larger than ground squirrels, native to the Andes mountains in South America. Along with their relatives, viscachas, they belong to the family Chinchillidae....
's whiskers can be up to a third of its body length.

Vibrissae offer an advantage to most animals that do not always have sight to rely on to navigate or to find food, or when the usefulness of non-tactile sense

Sense

Senses are the physiological methods of perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception....
s is limited. Some animals, such as house mice, can even detect air movements with their vibrissae.

A large part of the brain

Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
of many mammals is devoted to processing the nerve impulses from vibrissae because it is important to their survival. Information from the vibrissae is transmitted and processed through the trigeminal nerve

Trigeminal nerve

The trigeminal nerve is responsible for sensation in the face. Sensory information from the face and body is processed by parallel pathways in the central nervous system....
into the brainstem and thalamus

Thalamus

The thalamus is a pair and symmetric part of the brain. It constitutes the main part of the diencephalon....
before relaying to the barrel cortex

Barrel cortex

The barrel cortex refers to the dark-staining regions of layer four of the somatosensory neocortex of rodents where somatosensory inputs from the contralateral side of the body come in from the thalamus....
of the brain. Mammals use a great deal of energy to keep the follicles housing their whiskers warm and ready to use. Some animals - mainly rodents - actively palpate their vibrissae, a process known as whisking, whilst others use them merely as passive sensors.