Scrotum
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| Scrotum | |
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| The scrotum. On the left side the cavity of the tunica vaginalis has been opened; on the right side only the layers superficial to the Cremaster have been removed. | |
| Gray's | subject #258 1237 |
| Precursor | labioscrotal folds |
| MeSH | A05.360.444.661 |
| Dorlands/Elsevier | s_06/12726162 |
In some male mammals, the scrotum is a bag of skin and muscle containing the testicles. It is an extension of the abdomen, and is located between the penis and anus. The female homologue during fetal development is the labia majora.
In humans, and some other mammals, the base of the scrotum becomes covered with pubic hair at puberty.
The area behind the scrotum is the perineum.
Contents |
[edit] Function
The function of the scrotum appears to be to keep the testicles at a temperature slightly lower than that of the rest of the body. For the human, a temperature around 34.4 degrees Celsius (94 degrees Fahrenheit) seems to be ideal; 36.7 degrees Celsius (98 degree Fahrenheit) may be damaging to sperm count. The temperature is controlled by moving the testicles closer to the abdomen when it is cold, and away when hot. This is done by the contracting and relaxing of the cremaster muscle in the abdomen and the dartos fascia (muscular tissue under the skin) in the scrotum.
In most men, the cremaster muscle itself cannot be controlled voluntarily. Contraction of the abdominal muscles, and changes in intraabdominal pressure, often can lift and lower the testicles within the scrotum. Contraction of the muscle fibers of the dartos tunic (or fascia) is completely involuntary and results in the appearance of increased wrinkling and thickening of the scrotal skin. The testicles are not directly attached to the skin of the scrotum, so this dartos contraction results in their sliding toward the abdomen.
Although the ideal temperature for sperm growth varies between species, it usually appears, in warm-blooded species, to be a bit cooler than internal body temperature, necessitating the scrotum. Since this leaves the testicles vulnerable in many species, there is some debate on the evolutionary advantage of such a system. One theory is that the impregnation of females who are ill is less likely when sperm is highly sensitive to elevated body temperatures.
[edit] Health issues
A common problem of the scrotum is the development of masses. Common scrotal masses include
- sebaceous cyst, also called an epidermal cyst
- hydrocele
- hematocele
- spermatocele
- varicocele
Other conditions include:
- contact dermatitis: may cause redness, swelling, and itching of the entire scrotum. Can result from soaps, solvents, detergents, and natural irritants such as poison ivy.
- inguinal hernia
- yeast infection
- swelling resulting from conditions external to the scrotum, including:
- heart failure
- kidney or liver disease
[edit] Additional images
 Structure of the penis |
 The superficial branches of the internal pudendal artery. |
 Vertical section of bladder, penis, and urethra. |
[edit] See also
| Reproductive system |
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| Female - Cervix | Clitoris | Clitoral hood | Fallopian tubes | Bartholin's glands | G-spot | Hymen | Labium | Mammary glands | Ovaries | Skene's glands | Urethra | Uterus | Vagina | Vulva |
| Male - Urethra | Testes | Scrotum | Spermatic cord | Epididymis | Seminiferous tubules | Sertoli cell | Rete testis | Efferent ducts | Vas deferens | Seminal vesicles | Ejaculatory duct | Penis | Corpus cavernosum | Glans penis | Fundiform ligament | Foreskin | Frenulum | Prostate | Bulbourethral glands |
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HEAD: Skull - Forehead – Eye – Ear – Nose – Mouth – Tongue – Teeth – Jaw – Face – Cheek – Chin NECK: Throat – Adam's apple - Larynx TORSO: Shoulders – Spine – Chest – Breast – Ribcage – Abdomen – Belly button LIMBS: Arm – Elbow – Forearm – Wrist – Hand – Finger (Thumb - Index finger - Middle finger - Ring finger - Little finger) – Leg – Lap – Thigh – Knee – Calf – Heel – Ankle – Foot – Toe (Hallux) |
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