| Bulboid corpuscle | |
|---|---|
 End-bulb of Krause. | |
| Details | |
| Identifiers | |
| Latin | corpuscula bulboideum |
| FMA | 83603 |
| Anatomical terminology | |
The bulboid corpuscles (end-bulbs of Krause) are cutaneous receptors in the human body.
The end-bulbs of Krause were named after the German anatomist Wilhelm Krause (1833–1910). [1] [2]
The end-bulbs of Krause were thought to be thermoreceptors, sensing cold temperatures, but their function remained unknown. [3] 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." [4]
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.
End-bulbs are found in the conjunctiva of the eye (where they are spheroidal in shape in humans, but cylindrical in most other animals), in the mucous membrane of the lips and tongue, and in the epineurium of nerve trunks.
They are also found in the penis and the clitoris and have received the name of genital corpuscles; [5] in these situations they have a mulberry-like appearance, being constricted by connective-tissue septa into from two to six knob-like masses.[ citation needed ]
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.
In amniotes, the clitoris is a female sex organ. In humans, it is the vulva's most erogenous area and generally the primary anatomical source of female sexual pleasure. The clitoris is a complex structure, and its size and sensitivity can vary. The visible portion, the glans, of the clitoris is typically roughly the size and shape of a pea and is estimated to have at least 8,000 nerve endings.
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
In male human anatomy, the glans penis or penile glans, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and primary anatomical source of sexual pleasure. The glans penis is present in the male reproductive organs of humans and most other mammals where it may appear smooth, spiny, elongated or divided. It is externally lined with mucosal tissue, which creates a smooth texture and glossy appearance. In humans, the glans is located over the distal ends of the corpora cavernosa and is a continuation of the corpus spongiosum of the penis. At the summit appears the urinary meatus and at the base forms the corona glandis. An elastic band of tissue, known as the frenulum, runs on its ventral surface. In men who are not circumcised, it is completely or partially covered by a fold of skin called the foreskin. In adults, the foreskin can generally be retracted over and past the glans manually or sometimes automatically during an erection.
The G-spot, also called the Gräfenberg spot, is characterized as an erogenous area of the vagina that, when stimulated, may lead to strong sexual arousal, powerful orgasms and potential female ejaculation. It is typically reported to be located 5–8 cm (2–3 in) up the front (anterior) vaginal wall between the vaginal opening and the urethra and is a sensitive area that may be part of the female prostate.
An erogenous zone is an area of the human body that has heightened sensitivity, the stimulation of which may generate a sexual response, such as relaxation, sexual fantasies, sexual arousal and orgasm.
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are innervated by sensory neurons that convert mechanical pressure into electrical signals that, in animals, are sent to the central nervous system.
The female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The human female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a fetus to full term. The internal sex organs are the vagina, uterus, fallopian tubes, and ovaries. The female reproductive tract includes the vagina, uterus, and fallopian tubes and is prone to infections. The vagina allows for sexual intercourse and childbirth, and is connected to the uterus at the cervix. The uterus or womb accommodates the embryo, which develops into the fetus. The uterus also produces secretions, which help the transit of sperm to the fallopian tubes, where sperm fertilize ova produced by the ovaries. The external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris, and vaginal opening.
Tactile corpuscles or Meissner's corpuscles are a type of mechanoreceptor discovered by anatomist Georg Meissner (1829–1905) and Rudolf Wagner. This corpuscle is a type of nerve ending in the skin that is responsible for sensitivity to pressure. In particular, they have their highest sensitivity when sensing vibrations between 10 and 50 hertz. They are rapidly adaptive receptors. They are most concentrated in thick hairless skin, especially at the finger pads.
The Pacinian corpuscle, lamellar corpuscle or Vater-Pacini corpuscle is one of the four major types of mechanoreceptors for mechanical sensation) found in mammalian skin. This type of mechanoreceptor is found in both hairy, and hairless skin, viscera, joints, and attached to the periosteum of bone, primarily responsible for sensitivity to vibration. A few are also sensitive to quasi-static or low frequency pressure stimuli. Most of them respond only to sudden disturbances and are especially sensitive to vibration of a few hundreds hertz. The vibrational role may be used for detecting surface texture, such as rough and smooth. Most of the Pacinian corpuscles act as rapidly adapting mechanoreceptors. Groups of corpuscles respond to pressure changes, such as on grasping or releasing an object.
The clitoral crura are two erectile tissue structures, which together form a "V" shape. Crus is a Latin word that means "leg". Each "leg" of the V converges on the clitoral body. At each divergent point is a corpus cavernosum. Together with the vestibular bulbs, they form the clitoral root. The crura are attached to the pubic arch, and are adjacent to the vestibular bulbs. The crura flank the urethra, urethral sponge, and vagina and extend back toward the pubis. Each clitoral crus connects to the rami of the pubis and the ischium.
In female anatomy, the vestibular bulbs, bulbs of the vestibule or clitoral bulbs are two elongated masses of erectile tissue typically described as being situated on either side of the vaginal opening. They are united to each other in front by a narrow median band. Some research indicates that they do not surround the vaginal opening, and are more closely related to the clitoris than to the vestibule. They constitute the root of the clitoris along with the crura.
The corpus cavernosum of clitoris is one of a pair of sponge-like regions of erectile tissue of the clitoris. It is made of a sponge-like tissue that fills with blood during erection. This is homologous to the corpus cavernosum penis. The term corpora cavernosa literally means "cave-like bodies".
The perineal membrane is an anatomical term for a fibrous membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane.
The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typically described together as the genitourinary system.
In human male anatomy, the radix or root of the penis is the internal and most proximal portion of the human penis that lies in the perineum. Unlike the pendulous body of the penis, which is suspended from the pubic symphysis, the root is attached to the pubic arch of the pelvis and is not visible externally. It is triradiate in form, consisting of three masses of erectile tissue; the two diverging crura, one on either side, and the median bulb of the penis or urethral bulb. Approximately one third to one half of the penis is embedded in the pelvis and can be felt through the scrotum and in the perineum.
Human sexuality is the way people experience and express themselves sexually. This involves biological, psychological, physical, erotic, emotional, social, or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions, including the human sexual response cycle.
In most terrestrial mammals, the scrotum or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin containing the external spermatic fascia, testicles, epididymides, and vasa deferentia. The scrotum will usually tighten when exposed to cold temperatures.
In male human anatomy, the foreskin, also known as the prepuce, is the double-layered fold of skin, mucosal and muscular tissue at the distal end of the human penis that covers the glans and the urinary meatus. The foreskin is attached to the glans by an elastic band of tissue, known as the frenulum. The outer skin of the foreskin meets with the inner preputial mucosa at the area of the mucocutaneous junction. The foreskin is mobile, fairly stretchable and sustains the glans in a moist environment. Except for humans, a similar structure known as a penile sheath appears in the male sexual organs of all primates and the vast majority of mammals.
The suspensory ligament of the clitoris is a fibrous band at the deep fascial level that extends from the pubic symphysis to the deep fascia of the clitoris, anchoring the clitoris to the pubic symphysis. By virtue of this connection, the pubic symphysis supports the clitoris.
The clitoris is a female sex organ present in mammals, ostriches and other amniotes.
This article incorporates text in the public domain from page 1060 of the 20th edition of Gray's Anatomy (1918)
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