Chapter 4 Male Sexual Anatomy and Physiology
Chapter 4
Male Sexual Anatomy and Physiology
The Penis
• External anatomy of the penis includes:– Foreskin, glans, shaft, root
Why is it important to conduct regular genital self-exams, and what should a man look for?
The Penis
The Penis
• Internal anatomy of the penis includes:– Cavernous bodies (corpora cavernosa)– Spongy body (corpus spongiosum)– Penile urethra
The Penis
The Penis
• Corona• Frenulum• Glans
The Penis
The Scrotum
• Sac or pouch with two chambers• Muscle layer (tunica dartos)
– Pulls sac closer to body in cold temperatures• Spermatic cord
The Penis
The Testes
• Testes– Secrete male hormones– Produce sperm
• Cryptorchidism– Undescended testis
• Self-exam is recommended
Underlying Structures of the Scrotum
The Testes
• Seminiferous tubules– Site of sperm production
• Interstitial cells– Major source of androgens
• Epididymis– Sperm maturation
Internal Structure of a Testis
The Vas Deferens
• Move sperm from scrotum to ejaculatory duct through prostate
• Ejaculatory ducts open into the urethra
Male Sexual Anatomy
Male Sexual Anatomy
• Seminal Vesicle– Secretes 70% of seminal fluid
• Prostate Gland– Secretes 30% of seminal fluid
• Cowper’s Glands– Secretes fluid before ejaculations– May contain active, healthy sperm
• Semen (seminal fluid)– Volume is about 1 teaspoon– 200 to 500 million sperm
Erection
• Coordinated by autonomic nervous system– Arteries expand– Blood out flow cannot keep up with in flow
• Capacity for erection is present at birth
• Psychogenic and physiogenic erections
Ejaculation
• Spinal reflex triggers two phases– Emission
• Fluid in urethral bulb
– Expulsion• Semen expelled
• Retrograde ejaculation
• Nocturnal ejaculation
Male Sexual Anatomy during Ejaculation
Concerns about Sexual FunctioningPenis Size
• Penis size is seen as a symbol of virility
• Erect penises show less variation than flaccid
• Size NOT related to sexual satisfaction
• Penile augmentation
• Genital retraction syndrome
Concerns about Sexual Functioning
• Phimosis– Extremely tight foreskin
• Circumcision– Hygienic value & risk for STI’s question– Medical risks– AAP: moderate opposition
• Data not significant to recommend routine procedure
Male Circumcision
Male Genital HealthPenis Health-Care Issues
• Cleanliness– Smegma– Infections
• Reaction to vaginal secretions
• Injuries
• Penile cancer
Male Genital HealthTesticle Health-Care Issues
• Testicular Cancer
– More common in young men (20 to 35 years old)
– Risk factors
– Hard or irregular mass in testes
– Survival is greater than 90% if detected early
Male Genital HealthProstate Health-Care Issues
• Prostate diseases– Prostatitis
• enlarged and inflamed– Benign prostatic hyperplasia– Prostate cancer
• PSA test
• Treatment options for prostate cancer