Ejaculation of semen from the penis is caused by
A)a parasympathetic reflex that contracts the seminal vesicles,epididymis,and vas deferens.
B)a somatic reflex that initiates sperm production and motility,and contracts skeletal muscle surrounding the vas deferens.
C)voluntary relaxation of the internal urethral sphincter,and sympathetic stimulation of smooth muscle contraction in the walls of the ureters and the urethra.
D)sympathetic nerve firing,which initiates smooth muscle contraction in the epididymis,vas deferens,ejaculatory ducts,prostate,and seminal vesicles.
E)parasympathetic stimulation of smooth muscle in the ureters,urinary bladder,and urethra.

Question

Ejaculation of semen from the penis is caused by
A)a parasympathetic reflex that contracts the seminal vesicles,epididymis,and vas deferens.
B)a somatic reflex that initiates sperm production and motility,and contracts skeletal muscle surrounding the vas deferens.
C)voluntary relaxation of the internal urethral sphincter,and sympathetic stimulation of smooth muscle contraction in the walls of the ureters and the urethra.
D)sympathetic nerve firing,which initiates smooth muscle contraction in the epididymis,vas deferens,ejaculatory ducts,prostate,and seminal vesicles. 
E)parasympathetic stimulation of smooth muscle in the ureters,urinary bladder,and urethra.

Quizplus · Accepted Answer

Ejaculation is initiated by sympathetic nerve firing, which causes smooth muscle contraction in the epididymis, vas deferens, ejaculatory ducts, prostate, and seminal vesicles. This results in the expulsion of semen from the penis.

Ejaculation of Semen from the Penis Is Caused by