Erection and Ejaculation Flashcards
Neurovascular phenomenon resulting from changes in blood flow
Erection
Erection
Penis becomes rigid permitting entry into vagina
Ejaculation
Discharge of semen from penis
Vascular compartments of penis
Sinusoidal spaces of corpora cavernosa and corpus spongiosum
Penile smooth muscle role before and during erection
- Smooth muscle surrounds the vascular compartments of the penis.
- The SM contracts during the flaccid state and relaxes during erection.
Tunica albuginea
Tough fibroelastic covering (connective tissue) surrounding the corpora carnosa and corpus spongiosum
Flow of blood through vessels of the penis
- Dorsal artery
- Circumflex artery
- Cavernous artery
- Helicine arteries
- Sinusoidal spaces
- Circumflex vein
- Dorsal vein
Which structure surrounds the urethra?
Corpus spongiosum
What is a sinusoidal compartment?
A compartment that can vary in size/amount of volume it holds
Which muscles contract at the base of the penis to compress venous outflow?
- Ischiocavernosus skeletal muscle
- Bulbospongiosus skeletal muscle
Flaccid state of penis
- Arteries supplying vascular components are constricted.
- Penis contains little blood.
Erect state of penis
- Arteries dilate to increase blood flow of penis.
- Vascular compartments (sinuses) expand
- Veins are compressed (reduced blood outflow)
- Blood pressure in penis increases
- Penis becomes rigid
Dorsal and pudendal nerve
Afferent pathway
Pudendal and perineal nerves
Somatic NS
Cavernous nerve
Autonomic NS
If a patient had their spinal cord severed at L4, they would be…
able to have both a psychogenic and/or reflexogenic erection
Sexual response cycle
- Excitement phase
- Plateau phase
- Orgasmic phase
- Resolution phase
Excitement phase of male sexual response cycle
Includes psychogenic and/or reflexogenic erection
Plateau phase of male sexual response cycle
Intensification of excitement phase
Orgasmic phase of male sexual response cycle
- Includes ejaculation reflex (emission and expulsion)
- Rhythmic contractions of penis are accompanied by increase respiration and heart rate, generalized muscle contraction, and heightened emotion
Resolution phase of male sexual response cycle
- Return to pre-arousal state
- Includes latent period during which second erection is not possible
Emission in response to penile afferents
- Penile stimulation causes contraction of smooth muscle of epididymis, vas deferens, ejaculatory ducts, prostate
- Seminal vesicles to deposit sperm and glandular secretions into urethra
- Contraction of urinary bladder sphincter
Expulsion in response to urethral afferents
Filling of urethra stimulates rhythmic contraction of skeletal muscle (bulbospongiosus) at the base of penis to expel semen
Emission during ejaculation is stimulated by which pathway
Simultaneous sympathetic and parasympathetic reflexes
Expulsion during ejaculation is stimulated by which pathway
Somatic (motor) reflex
Orgasm sensation may result from…
Near simultaneous activation of sympathetic and parasympathetic tension-release process
Which reflex loop or pathway is responsible for the relaxation of smooth muscle?
- Pudendo-cavernosal reflex loop
- Psychogenic pathway
Which reflex loop or pathway is responsible for the compression of venous outflow?
Bulbocavernosus reflex loop
Which reflex loop or pathway is integrated with higher centers?
Ascending spinal pathway
