physiology of human s exual response
DESCRIPTION
بسم الله الرحمن الرحيم. Physiology of Human S exual Response . Dr.Mohammed Sharique Ahmed Quadri Assistant professor physiology Al M aarefa College. Components of Male S exual A ct . Coitus or copulation Male sex act involves two components - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/1.jpg)
1
Physiology of Human Sexual Response
Dr.Mohammed Sharique Ahmed QuadriAssistant professor physiology
Al Maarefa College
بسم الله الرحمن الرحيم
![Page 2: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/2.jpg)
Components of Male Sexual Act
• Coitus or copulation
• Male sex act involves two components
– Erection: Hardening (increase in length and width)of normally flaccid penis, as result of increase blood flow in “erectile tissue” of penis.
– Ejaculation : forceful expulsion of semen into the urethra and out of the penis
![Page 3: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/3.jpg)
Sexual Response Cycle in males • Sexual response is divided into four phases – Excitement phase(Arousal).• Initiated by either physical or psychological stimuli• Heightened sexual awareness.• Vasocongestion(engorgement of sexual organs)-
includes erection
– Plateau phase:• Includes intensification of earlier responses • Characterized by steadily increasing heart rate,
blood pressure, respiratory rate, and Myotonia (increase muscle tone).
![Page 4: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/4.jpg)
Sexual Response Cycle in males
– Orgasmic phase• Includes ejaculation, Rhythmic throbbing of
pelvic muscles• All generalized body responses reaches to peak– Heavy breathing – Heart rate upto 180 beats / min–Marked generalized skeletal muscle contraction– Heightened emotions
• These responses that are collectively experienced as intense physical pleasure( feeling of release) an experience known as orgasm.
![Page 5: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/5.jpg)
Sexual Response Cycle in males
–Resolution phaseReturn of genitalia and body systems to prearousal state• Erection subside(decrease blood flow to penis)• Deep relaxation ( may feel fatigue)• Muscle tone returns to normal • Cardiovascular and respiratory activity returns
to prearousal state.Following orgasm men enters refractory period of variable duration before sexual erection can produce another excitation.
![Page 6: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/6.jpg)
Sexual Response Cycle in Females • Female sexual cycle is similar to male cycle• Also experience same four phases of the sexual cycle– Excitement:• Initiated by either physical or psychological stimuli• Parasympathetically induced vasodilation of
arterioles in vagina & external genitelia( specially clitoris), that results in– Swelling of labia and erection of clitoris (bulbs engorge with
blood)– Secretion of fluid in vagina (act as a lubricant)
• Erection of nipples & enlargement of breast as a result of vasocongetion.• Flushing ( increased blood flow through skin)
![Page 7: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/7.jpg)
Erectile tissue in females
![Page 8: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/8.jpg)
Sexual Response Cycle in Females
– Plateau:• Changes initiated during excitement phase intensify• Systemic responses similar to those in male occur
– Increase heart rate– Increase respiratory rate – Increase muscle tension
• Vasocongetion of lower third of vagina reduces its inner capacity• Uterus raises upwards-enlarging upper two third of
vagina(creates space for ejaculate deposition).
![Page 9: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/9.jpg)
Sexual Response Cycle in Females – Orgasm:• Sympathetic stimulation triggers rhythmic contraction
of pelvic muscle • More intense contraction of lower two third of vagina • Systemic responses similar to that of male orgasm• Experience in females is similar to that in males
except– No female counterpart to ejaculation– Do not become refractory following an orgasm
( multiple orgasm possible)– Resolution • Pelvic vasocongestion and systemic
manifestations gradually subside• Time of great physical relaxation
![Page 10: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/10.jpg)
Erection of Penis • Accompanied by engorgement of erectile tissue with
blood• Erectile tissue(cords of sponglikevascular spaces) :– Corpora cavernosa: two paired on dorsal side– Corpus spongiosum: one on ventral side
• During sexual arousal, these arterioles reflex dilate- erectile tissue fills with blood- penis to enlarge both in length and width and to become more rigid.
• Veins that drain the erectile tissue are mechanically compressed –reducing venous outflow and thereby contributing even further to vasocongestion.
![Page 11: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/11.jpg)
Erectile tissue in Males
![Page 12: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/12.jpg)
Erection reflex
![Page 13: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/13.jpg)
Role of Nitric Oxide in Penile Erection
Vasodilatation and vascular engorgement
Phosphodiesterase 5
sildenafil
Parasympathetic stimulation
NO release from vascular endothelium
Acivates Guanylate cyclase
Relaxation of arteriolar smooth muscles
Activates cGMPbreaks down
![Page 14: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/14.jpg)
Ejaculation
• Also a spinal reflex• Stimulated by sympathetic nervous system • Occurs in two phases:– Emission– Expulsion
![Page 15: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/15.jpg)
Ejaculation – Emission: • Movement of semen into the urethra.• Sympathetic impulses cause sequential
contraction of smooth muscles in the prostate, reproductive ducts, and seminal vesicles. • This contractile activity delivers semen into the
urethra. • During this time, the sphincter at the neck of
the bladder is tightly closed to prevent semen from entering the bladder and urine from
![Page 16: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/16.jpg)
Ejaculation • Expulsion :– Forcible expulsion of semen from the urethra out
of the penis– Filling of urethra with semen activates rhythmic
contraction of muscle at the base of penis- forcibly expelling semen out of urethra.
![Page 17: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/17.jpg)
Erectile Dysfunction(impotence) • Repeated inability to get or keep an erection firm enough for
sexual intercourse• Causes : • Damage to nerve arteries or smooth muscles
– as a result of disease e.g. Diabetes, kidney disease, chronic alcoholism, multiple sclerosis
– Damage resulting from surgerye.ge prostate and bladder surgeries • Medicines:
– Many antihypertensive, antidepressants, cimetidine• Psychological factors:
– Stress, anxiety, , depression, fear of sexual failureTreatment :
Sildenafil citrategene therapy is now being tested
![Page 18: Physiology of Human S exual Response](https://reader036.vdocument.in/reader036/viewer/2022062521/568166b1550346895ddaad26/html5/thumbnails/18.jpg)
18
References
• Human physiology by Lauralee Sherwood, seventh edition
• Text book physiology by Guyton &Hall,11th edition
• Text book of physiology by Linda .s contanzo,third edition