The bulboid corpuscles (end-bulbs of Krause, Krause corpuscles) are
cutaneous receptors in humans and other animals.
The end-bulbs of Krause were named after the German
anatomist
Anatomy () is the branch of morphology concerned with the study of the internal 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 scien ...
Wilhelm Krause (1833–1910).
Function
The end-bulbs of Krause were thought to be
thermoreceptor
A thermoreceptor is a non-specialised sense Cutaneous receptor, receptor, or more accurately the receptive portion of a sensory neuron, that codes absolute and relative changes in temperature, primarily within the innocuous range. In the mammalian ...
s, sensing cold temperatures, but in early research their function remained unknown. Recently optogenetic studies revealed their role in sexual stimulation and mating behavior in mice:
"Optogenetic activation of male Krause corpuscle afferent terminals evoked penile erection, while genetic ablation of Krause corpuscles impaired intromission and ejaculation of males as well as reduced sexual receptivity of females. Thus, Krause corpuscles, which are particularly dense in the clitoris, are vibrotactile sensors crucial for normal sexual behavior."
Structure
They are minute cylindrical or oval bodies, consisting of a capsule formed by the expansion of the connective-tissue sheath of a medullated fiber, and containing a soft semifluid core in which the axis-cylinder terminates either in a bulbous extremity or in a coiled-up plexiform mass.
Location
End-bulbs are found in the
conjunctiva
In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...
of the
eye (where they are spheroidal in shape in humans, but cylindrical in most other animals), in the
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...
of the lips and
tongue
The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...
, and in the
epineurium of
nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...
trunks.
Krause corpuscles are found in the
penis
A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate.
The term ''pen ...
and the
clitoris
In amniotes, the clitoris ( or ; : clitorises or clitorides) is a female sex organ. In humans, it is the vulva's most erogenous zone, erogenous area and generally the primary anatomical source of female Human sexuality, sexual pleasure. Th ...
and sometimes are referred to as genital corpuscles;
in these situations they have a mulberry-like appearance, being constricted by connective-tissue septa into from two to six knob-like masses.
In the
synovial membranes of certain joints, e. g., those of the fingers, rounded or oval end-bulbs occur, and are designated articular end-bulbs.
References
External links
Description at cirp.org
{{Portal bar, Anatomy
Sensory receptors