34/35. Male Reproductive System Flashcards
Gender
How an individual identifies
May not align with sex
Chromosomal sex
XX or XY chromosomes or some other combination
Phenotypic sex
Appearance of genitalia
Characteristics of biological sex and gender
We are conditioned to view sex and gender as binary constructs
Sex does not equal gender
Both sex and gender occur on a spectrum
What does intersex mean
Various combinations in which a person is born with a reproductive or sexual anatomy that doesn’t fit the typical definitions of female or male
About 1/100 births
Types of Male reproductive structures
Include primary and secondary sex organs
Primary male sex organs
Testes - produce sperm
Secondary male sex organs
Epididymis
Vas deferens
Seminal vesicles
Prostate gland
Bulbourethral gland
Characteristics of scrotum
Pouch that holds testes
Responds to external temperature
Consists of dartos muscle (smooth muscle) that creates wrinkles on skin to regulate surface area and heat loss
Tunica of the testes
Tunica vaginalis and tunica albuginea
Structure/function of tunica vaginalis
Serous sac covering testis (from peritoneum)
Structure/function of tunica albuginea
Fibrous capsule of testis
Invaginates to create lobules composed of coiled seminiferous tubules
Location of sperm production
Pathway of sperm in the testes
Produced in the seminiferous tubules
Carried into the epididymis
Then enters vas deferens
Characteristics of the epididymis
Contains highly coiled duct
Sperm becomes fully mature, become motile
Takes bout 20 days
Sperm is ejaculated from epididymis
Sperm CN be stored for several months and then are phagocytized if not released
Characteristics of the spermatic cord
Tube of fascia containing structures from the abdomen to scrotum
Structures leave abdomen, travel through the inguinal canal to enter the spermatic cord
Includes cremaster muscle
Characteristics of cremaster muscle in spermatic cord
Skeletal muscle continuation from internal oblique
Elevate and lower testes to regulate temperature of testes
Blood supply and sperm transportation of spermatic cord
Testicular (gonadal) artery is blood supply to testes
Pampiniform plexus is testicular veins that branch out and surround testicular artery to cool blood supply to testes
Vas deferens is a muscular tube that transports sperm during ejaculation to the prostate
Characteristics of the testicular vein and artery
Testicular (gonadal) artery ordinates in abdominal aorta
Testicular (gonadal) vein merges with the left renal vein on the left side and the IVC on the right side
Both artery and vein travel through inguinal canal to enter spermatic cord
Testicular vein branches to form pampiniform plexus
Descent of the testes
Body is too hot to produce viable sperm, testes descend into scrotum where it’s 5 degrees cooler
Gubernaculum guides testes descent through inguinal canal into scrotum
What is an inguinal hernia
Increasing intraabdominal pressure pushes intestines through weak areas of the abdominal wall and into the inguinal canal & scrotum
Can cut off blood supply to intestine causing death of tissue
More common in males due to descent of testes in inguinal canal
Abdominal wall often repaired with mesh patch
What is a vasectomy
Method of birth control
Surgical procedure cut and seal the vas deferens
Sperm are produced but can no longer exist the body, broken down in epididymis
Reversal is possible but not always successful
Characteristics of the vas deferens
Vas deferens enters pelvic cavity through inguinal canal
Vas deferens joined by seminal vessicle to create ejaculatory duct within prostate gland
Characteristics of the seminal vesicles
Located behind bladder
Release into semen:
Fructose- energy supply for sperm cells
Prostaglandins- promote dilation of cervical canal and contraction of uterus
Bicarbonate- buffers acidic environment
Characteristics of prosthetic gland
Prostate gland located inferior to bladder
Ejaculatory duct joins the urethra within the prostate gland
Prostate gland releases into semen:
Seminalplasmin-antibiotic to combat urinary tract infections
Prostate specific antigen (PSA)- liquefies semen after ejaculation
What is prostate cancer?
Most common malignancy in men >50 yrs
Early states are generally asymptomatic
Can metastasize to other parts of body if untreated
Digital rectal exam performed by physicians to feel for bumps or hard spots on prostate
Characteristics of the urethra and its specific regions
Carries urine and seminal fluid (semen) to exit the penis
Has specific regions:
Prostatic urethra- through prostate, joined by ejaculatory ducts
Penile (spongy) urethra- through penis
Characteristics of the bulbourethral gland
Produces mucus-like substance that conditions penile urethra before ejaculation
Neutralizes acidic urine and lubricates urethra
Characteristics of the penis and tissue
Copulatory organ in chromosomal males
Comprised of highly vascularized erectile tissue with a substantial blood supply that becomes engorged with blood during sexual arousal
2 sets of erectile tissue:
Bulb of penis extends as corpus spongiosum
Crura extend and dime together as corpora cavernosa
Structures of penis
Root of penis- attached part not visible
Body of penis- free external portion
Glans- enlarged distal end
Foreskin (prepuce)- cuff of skin surrounding glands
External urethral orifice- end of urethra
Formation of the penile structures
Bulb and crura form root of penis below pubic symphysis
Corpus spongiosum and corpora cavernosa form body of penis
Corpus spongiosum expands distally to form the glans
Penile urethra travels through corpus spongiosum
Muscles of the penis
Bulbospongiosus muscle- sheet of muscle covering bulb of penis
Ischiocavernosus muscle- sheet of muscle covering each crus of penis
Muscles assist with erection and expulsion of fluid from urethra
What is penile circumcision?
Surgical procedure to remove foreskin of penis
Common in some countries but less world wide
Benefits: reduced risk of UTI as infant
Drawbacks: possible loss of sensation and lack of consent for procedure
Blood supply to penis
Internal iliac artery gives off a branch, internal pudendal artery, that leaves pelvis and travels to external genitalia to supply blood to erectile tissues
Internal pudendal artery gives rise to dorsal and deep arteries of the penis
Innervation of the penis
Pudendal nerve originates from sacral spinal cord segments
Leaves pelvis and runs underneath pelvic floor towards penis
Gives off many branches, one branch is the dorsal nerve of the penis which Carrie’s general sensation from the penis
Sympathetics and parasympathetics to the erectile tissues arise from the inferior hypogastric plexus
What occurs during erection in the Sexual response function
Erection of penis:
parasympathetics dilate arteries increasing blood flow to tissues
muscles relax allowing tissue to expand
constriction of veins by tissue slows blood drainage
What occurs during ejaculation in the sexual response function
Sympathetics cause strong contraction of smooth muscles throughout reproductive ducts and glands
Constrict internal urethral sphincter to prevent semen from entering bladder
Rapid contraction of bulbospongiosus muscle pushes semen through urethra and out
Characteristics of spermatogenesis
Formation of sperm
Spermatogonia differentiate into sperm, takes ~75 days
Occurs in seminiferous tubules of testes
Produce 400 million sperm daily
Starts at puberty til death
Broke into 3 stages: formation of spermocytes, meiosis, and spermatogenesis
Step 1 of spermatogenesis
Formation of spermocytes
Spermatogonia (stem cells) located in outer region of seminiferous tubules
Spermatogonia undergo continuous mitosis that results in 2 daughter cells:
Type A- remain in outer region to maintain germ cell line
Type B- move toward lumen as primary spermocyte
Step 2 of spermatogenesis
Meiosis
Process of 2 subsequent divisions where diploid cell ends with 4 haploid cells
Meiosis 1- primary spermatocyte divides into 2 secondary spermatocyes
Meiosis 2- secondary spermatocytes divide into haploid spermatids
Step 3 of spermatogenesis
Spermatids go through a process to differentiate into sperm
Sperm have 3 parts:
Head with nucleus
Midpiece with mitochondria to produce energy for tail
Tail- flagellum that propels
Sperm detached from epithelium of seminiferous tubule and enters lumen
