Module 2 Section 4

Question 1

what is sexual intercourse

Answer 1

in humans it requires the delivery of sperm into the female vagina through the sex act, which is also known as sexual intercourse, coitus, or copulation

Question 2

what is an erection

Answer 2

• when the penile tissue fills with blood allowing the penis to become rigid and permit its entry into the vagina
• the erectile tissue of the penis is made up of 3 columns of sponge-like vascular spaces
• these columns are known collectively as the corpora cavernosa
• during arousal, the arterioles that supply these vascular spaces dilute resulting in the penis being enlarged and rigid

Question 3

what is the erection relfex

Answer 3

• thoughts about sex or stimulation of mechanoreceptors in the glans penis initiate the erection reflex
• this is a spinal reflex and the erection generating centre lies in the lower spinal cord

Question 4

what are the 3 main actions for the activation of the erection reflex

Answer 4

1. inhibiting the sympathetic supply to the penile arterioles. this removes the tonic vasoconstrictor actions of the sympathetic system
2. activates the parasympathetic supply to the penile arterioles to cause vasodilation via a NO-mediated mechanism
3. activates the parasympathetic supply to the bulbourethral glands to secrete mucus for lubrication

Question 5

what is erectile dysfunction

Answer 5

• referred to as the inability to obtain and maintain an erection rigid enough for sex
• if erectile dysfunction is an ongoing issue, it could be a sign of an underlying health condition that requires treatment

Question 6

what is ejaculation

Answer 6

ejaculation is also the result of a spinal reflex, and is mediated by the same tactile and psychological stimuli that cause an erection

Question 7

explain step 1 of ejaculation - emission

Answer 7

• increased sympathetic activity causes smooth muscle contractions in the prostate, reproductive ducts, and seminal vesicles
• the timing is coordinated such that prostatic fluid, then sperm, then seminal vesicle fluid is delivered into the urethra
• this mixture is called semen
• the sphincter at the neck of the bladder is also contracted to prevent urine release

Question 8

explain step 2 of ejaculation - expulsion

Answer 8

• the filling of the urethra with semen triggers the activation of skeletal muscles at the base of the penis
• this increases the pressure and forcibly expels the semen
• this changes the pressure within the urethra and forcibly expels the semen

Question 9

what are the 4 stages of the male sexual response cycle

Answer 9

1. excitement phase: this includes a heightened sexual awareness and erection
2. plateau phase: this has more generalized responses such as increased heart rate, blood pressure, and respiratory rate
3. orgasmic phase: this includes ejaculation as well as other physical and emotional responses
4. resolution phase: the return of the body to its pre-arousal

once ejaculation has occurred, a temporary refractory period occurs in which further sexual stimulation cannot trigger another erection

Question 10

explain the first phase of the female sexual response cycle - excitement

Answer 10

• excitatory stimuli can be both psychological or physical stimuli
• stimulation of the clitoris and the surrounding area activates a spinal reflex that activates the parasympathetic system to dilate the arterioles throughout the vagina and external genitalia
• the nipples also become erect and there is an increase blood supply to the skin
• the clitoris, like the penis, contains erectile tissue and becomes erect
• dilation of arterioles in the vaginal walls causes vasocongestion of the capillaries, which forces fluid out of the vessels and into the vagina
• this fluid, along with secretions from Bartholin’s gland, serves as the primary lubricant for intercourse

Question 11

explain the second phase of the female sexual response cycle - plateau

Answer 11

• the uterus raises upward, lifting the cervix and enlarging the upper portion of the vagina
• this tenting effect creates space for ejaculated semen
• breathing, heart rate, and blood pressure of the female also continue to increase

Question 12

explain the third phase of the female sexual response cycle - orgasm

Answer 12

• if erotic stimulation continues, the sexual response culminates in orgasm, as sympathetic impulses lead to rhythmic contractions of the pelvis musculature
• there is no female equivalent to ejaculation

Question 13

explain the fourth phase of the female sexual response cycle - resolution

Answer 13

• after orgasm, heart rate, blood pressure, and breathing return to normal
• this phase is marked by a general sense of well-being, enhanced, and, fatigue
• some women are capable of a rapid return to the plateau phase with further sexual stimulation