WEEK 4: PHYSIOLOGY OF SEX RESPONSE Flashcards
What are the other 2 names for sexual intercourse?
*copulation
*Coitus
State the 2 components of male sex
*Erection
*Ejaculation
Describe the 4 phases of male sexual response cycle
1.Excitory phase: involves erection and mucus production
2.Plateau phase: intense ejection, increasing heart beat,breathing. Blood pressure and muscle tension
3.Orgasmic phase: Ejaculation and sexual pleasure
4.Resolution phase: return of genitalia and body systems to the pre arousal state
Describe the 4 phases of sexual response in females
1.Excitment: can be initiated by physical or psychological stimuli
2.Plateau: increased excitement phase effects, increased blood pressure, heart beat, respiratory rate and muscle tension
3.Orgasm: sexual pleasure
4.Resolution: pelvic vasocongestions and systemic manifestations subside, great physical relief
What is erection?
It is the hardening of a normally flaccid penis to permit it’s entry into the vagina
How is an erection accomplished?
Engorgement of the penis erectile tissue with blood as a result of parasympathetically induced penile arteriole vasoconstriction and mechanical compression of the veins resulting in an increase in the length and width of the penis and to become hardened
Describe the erection reflex
NOTE;
*Touching of the glans penis results in activation of its mechanoreceptors which are the once
*Which resulting in the reaction generation center in the lower spinal cord which trigger of the parasympathetic system.
1.Parasympathetic stimulation Nitric oxide (NO) release
2.NO activates guanylate cyclase (membrane-bound enzyme) in the arteriolar smooth muscles
3.Guanylate cyclase activates cyclic guanosine monophosphate (cGMP)
4.cGMP causes penile arterioles to dilate Erection
5.cGMP then broken down by phosphodiesterase 5 (PDE5) (another intracellular protein)
A spinal reflex response
Mechanoreceptors in glans penis
Erection-generating center
Parasympathetic stimulation triggers nitric oxide pathway
Some influence from brain
What is erectile dysfunction ( impotence)?
Failing to achieve or maintain an erection suitable for sexual intercourse
State the possible causes of erectile dysfunction
*anxiety
*Certain medications which may lead to Interference with autonomic function
*Problems with blood flow to the penis
Describe how sildenafil (Viagra) helps in alleviating erectile dysfunction
Viagra amplifies and prolongs an erectile response triggered by usual means of stimulation.
1.Parasympathetic stimulation results in Nitric oxide (NO) release
2.NO activates guanylate cyclase (membrane-bound enzyme) in the arteriolar smooth muscles
3.Guanylate cyclase activates cGMP (an intracellular second messenger)
4.cGMP causes penile arterioles to dilate
5.vasodilation results in Erection
6.cGMP then broken down by Phosphodiesterase 5 (PDE5) (another intracellular protein)
*Viagra inhibits PDE5
*Prolongs erection- sex act achieved as a result
What is ejaculation?
Forceful expulsion of semen into the urethra and out of the penis
Name and describe the 2 phases of ejaculation of smooth muscles of the reproductive ducts and accessory sex glands
Emission phase: emptying of sperm and accessory sex gland secretions (semen) into the urethra
How?
*Through sympathetic stimulation which results in contraction of smooth muscles in the walls of reproductive ducts and accessory sex glands
Expulsion phase: forceful expulsion of semen from the penis
How?
*filling of the urethra triggers nerve impulses that activate skeletal muscles at the base of the penis.Rhythmic contraction of these muscles that occur in 0.8 second intervals increase pressure within the penis, forcibly expelling the semen through the urethra to the exterior.
Describe orgasm
Involuntary rhythmic throbbing of pelvic muscles and peak intensity of the overall body responses that were climbing during the earlier phases. Heavy breathing, increased heart rate and generalized skeletal muscle contraction and heightened emotions are characteristics. These overall responses that culminate sex act are associated with an intense pleasure characterized by a feeling of release and complete gratification.
Orgasm- alsocalled sexual climax
*Includes ejaculation (emission & expulsion) and other responses that are collectively experienced as intense physical pleasure
Describe the resolution phase
Sympathetic vasoconstrictor impulses slow the inflow of blood into the penis, causing the erection to subside.A deep relaxation ensues , accompanied by a feeling of fatigue.Muscle tone returns to normal, while the cardiovascular and respiratory systems return to their prearousal level of activity
Why can’t males experience multiple orgasms within a matter of minutes,as sometimes females do?
Once ejaculation has occurred,a temporary refractory period of variable duration ensues before sexual stimulation can trigger another erection
