Male and Female Internal Genital Organs

Male Internal Genital Organs

• Testes: Produce sperm and testosterone, located within the scrotum.
• Epididymis: Located next to the testes, involved in sperm maturation.
• Ductus deferens: Thick-walled tubular structure that carries sperm from the epididymis to the ejaculatory duct.
• Seminal vesicles: Produce semen, a fluid that activates and protects sperm.
• Prostate gland: Surrounds a portion of the urethra, secretes alkaline fluid to neutralize acid in the urethra and stimulate sperm motility.
• Bulbourethral glands (Cowper's glands): Two small glands that discharge a component of seminal fluid into the urethra.
• Ejaculatory duct: Begins at the seminal vesicles, passes through the prostate, and empties into the urethra, carrying semen during ejaculation.

Female Urethra

• Length: 4-6 cm.
• Location: Lies anterior to the vagina.
• Passage: Passes through the pelvic diaphragm and external urethral sphincter along with the vagina.
• External Urethral Sphincter: Under voluntary control, innervated by branches from the pudendal nerve, remains contracted.

Micturition Reflex

• Animation for the Micturition Reflex exists.

Urethra

• Urethra (Male): Muscular tube, 18-30 cm long, leads to the external urethral orifice. Provides an exit for both urine and semen.
• Urethra (Female): 4-6 cm long, carries only urine.

### Urinary System

• Internal Urethral Sphincter: Involuntary sphincter made of smooth muscle, prevents retrograde movement of semen into the bladder during ejaculation.
• Internal Urethral Orifice: Leads to the urethra.

### External Urethral Sphincter

• Part of the UG (urogential diaphragm), supports the contents of the deep pelvis.
• Provides a means of stopping urine escape, under voluntary control via somatic efferents (pudendal nerve).

Urinary Bladder

• Hollow organ: Strong muscular walls (smooth muscle) allow for distensibility.
• Detrusor Muscle: Forms the bladder wall.
• Location: Lies mostly inferior to the peritoneum in the deep pelvis, posterior to the pubic symphysis when empty. Ascends into the anterior abdominal region and enters the false pelvis when filled.
• Always contains some urine: Even after emptying.

### Anatomic Regions of the Bladder

• Apex: Anterior aspect near pubic symphysis.
• Fundus (base): Posterior wall, opposite the apex.
• Body: Major portion between apex and fundus.
• Neck: Where the fundus and inferolateral surfaces meet.
• Trigone: Area defined by a smooth internal surface formed by the two ureters and the internal urethral orifice. Sensitive to expansion/stretch.

Ureters

• Length: 25-30 cm.
• Structure: Muscular tubes running through the abdomen along the pelvic brim.
• Function: Carry urine from the kidneys to the bladder.
• Oblique entry into the bladder: Creates a flap valve that prevents urine reflux back towards the kidney during bladder emptying.

Neural control: Ureters

• Innervation: Via the autonomic nervous system (ANS) plexus.
• Sympathetic fibers: Carry afferent pain information to spinal cord segments T11-L2. Refer pain along subcostal, ilioinguinal, and genitofemoral nerves.

Micturition Anatomy and Function

• The bladder stores urine and is connected to the outside of the body by the urethra.
• The internal sphincter is a muscle that helps to prevent urine leakage, it is controlled by the autonomic nervous system.
• The external sphincter is a muscle that is controlled by the somatic nervous system. This allows for voluntary control of urine retention.

Neural Control of Micturition Reflex

• The parasympathetic nervous system stimulates bladder contraction and is responsible for emptying the bladder.
• The sympathetic nervous system helps to maintain continence (preventing urine leakage).
• The somatic nervous system allows voluntary control of urine retention, which involves consciously engaging the external sphincter to prevent emptying the bladder.

Parasympathetic and Sympathetic Roles During Urination

• During urination, parasympathetic activation causes bladder contraction and relaxation of the internal sphincter, facilitating the flow of urine.
• During voluntary urine retention, the sympathetic nervous system is active, aiding in maintaining continence.
• The external sphincter remains contracted during this time until the individual decides to urinate.

Urine Retention

• The external sphincter is responsible for voluntary control, allowing conscious retention of urine even when the bladder is full.

Spinal Cord Lesions and Bowel/Bladder Function

• Lesions above S2-S4 (sacral segments) can cause a spastic bladder and bowel. This means that the bladder and bowel may contract uncontrollably, leading to incontinence. This is due to the loss of voluntary control over the muscles.
• Lesions at S2-S4 can result in a flaccid bladder and bowel, caused by damage to the nerves that control these organs. This results in loss of muscle tone and lack of awareness of bladder fullness.

Crede Maneuver

• This technique involves manually applying pressure to the bladder to help empty it in cases of impaired neural control.
• This is often used in cases of flaccid bladder when voluntary emptying is not possible.

Genital Anatomy and Function

• Male and female reproductive and urinary systems share some structures.
• These systems are controlled by both autonomic and somatic nervous systems.

Neural Control of Bowel Function

• The autonomic nervous system controls peristalsis, the movement of food through the digestive tract.
• The sympathetic nervous system regulates sphincter tone and helps maintain continence.
• Defecation (bowel emptying) involves a complex interplay of voluntary and involuntary control.

Diet and Spinal Cord Lesions

• Diet is crucial for maintaining bowel regularity and preventing complications like constipation.
• This is even more important in individuals with spinal cord injuries, as bowel function is often compromised.
• High fiber diets and adequate hydration can help prevent constipation in individuals with spinal cord injuries.

This quiz explores the anatomy and functions of male and female internal genital organs. Focus is placed on structures such as testes, epididymis, ductus deferens, and the female urethra. Understand the roles of these organs in reproduction and bodily functions.