!Penis
!!Anatomical overview
The human penis is an external male sexual organ. It is a __reproductive__, intromittent organ that additionally serves as the __urinal duct__. The main parts are the root (radix); the body (corpus); and the epithelium of the penis including the shaft skin and the foreskin covering the ((Reproductive - Penis - Glans and Foreskin|glans penis)).

The internal structures of the penis consist mainly of cavernous, __((Reproductive - Penis - Cavernous Body|erectile tissue))__, which is a collection of ((Circulatory - Blood|blood)) sinusoids separated by sheets of connective tissue (trabeculae).

The body of the penis is made up of three columns of tissue: two corpora cavernosa on the dorsal side and corpus spongiosum between them on the ventral side. The enlarged and bulbous-shaped end of the corpus spongiosum forms the __glans penis__, which supports the ((Reproductive - Penis - Glans and Foreskin|foreskin)), or __prepuce__, a loose fold of skin that in adults can retract to expose the glans.

The human male ((Urinary tract - Mucosa (Urothelium)|urethra)) passes through the ((Reproductive - Prostate Gland|prostate gland)), where it is joined by the ((Reproductive - Seminal Duct, Prostate Ducts, Seminal Vesicle|ejaculatory duct)), and then through the penis. The urethra traverses the corpus spongiosum, and its opening, the meatus lies on the tip of the glans penis. It is a passage both for urine and for the ejaculation of semen.

((Musculoskeletal - Skeletal Muscles|Striated muscles)) (Musculus ischiocavernosus, Musculus bulbospongiosus) help with __erection and ejaculation__, which are initiated by parasympathetic nerves upon __sexual arousal__.

{img fileId="259" thumb="box"}

!!Brain
{img fileId="202" thumb="box"}

{img fileId="355" thumb="box"}insular cortex
graphic: wikipedia, Henry Gray

!!!Relay
__Cerebral Cortex __(-/+): ((Integumentary - Skin - Epidermis|Epidermis)), ((Nervous - Sensory Innervation|Sensitivity)), ((Urinary tract - Mucosa (Urothelium)|Urethra))
{img fileId="125" thumb="box"}Cut through cerebral cortex insular region

{img fileId="104" thumb="box"}Cut through sensory and motoric areas

__Cerebral Medulla__ (-/+): ((Reproductive - Penis - Cavernous Body|Corpora Cavernosa)), ((Circulatory - Veins|Blood))- and ((Circulatory - Lymph-Vessels|Lymph vessels)), ((Musculoskeletal - Skeletal Muscles|Striated Muscles))
{img fileId="175" thumb="box"}Cut through cerebral medulla

__Cerebellum__ (+/-): ((Integumentary - Skin - Dermis (Leather Skin)|Dermis)) incl ((Reproductive - Penis - Dermis and Sebaceous Glands|sebaceous glands))
{img fileId="174" thumb="box"}Cut through cerebellum

__Midbrain__ (+/-): ((Organ Walls - Smooth Muscle Layer|Smooth muscle cells))
compare __Brain Stem__ {img fileId="190" thumb="box"}


