Exam 4: Male Reproductive System Flashcards
Gonads
testes in the male, ovaries in the female
-functions: produce gametes (sex cells): sperm or oocytes, produce sex hormones
Accessory Reproductive Organs
- include “ducts” that transport/store the gametes, glands that secrete substances for the gametes’ well-being, and the external genitalia
Reproductive System and Puberty
- not fully formed until then
- at puberty hypothalamus secretes hormones that tell anterior pituitary to release FSH (follicle stimulating hormone) and LH (luteinizing hormone), which act on ovaries and testes
- so you need FSH and LH to start gamete maturation and increased sex hormone production by the gonads
- hypothalums–>anterior pituitary–>FSH and LH–>gonads
Testis Function and External Anatomy
- functions: produce sperm and produce androgens (male sex hormones)
- suspended in scrotum
Scrotum
-function: keeps testes 3 degrees C cooler than internal body temperature so sperm can be produced (if too warm, sperm won’t develop)
Spermatic Cord
- runs from each testis to abdomen
- contains blood vessels and nerves and the ductus (vas) deferens
Testis Internal Anatomy
- each testis divided into a series of internal compartments called lobules
- each lobule contains up to 4 seminiferous tubules within the seminiferous tubules are: spermatogonia, developing sperm Sustentacular cells
- between seminiferous tubules is some connective tissue, with interstitial cells
Spermatogonia
- sperm stem cells or parent cells
- at base/edge of seminiferous tubules
Sustentacular Cells
- nurse cells/sertoli cells
- nourish and support developing sperm
Intersticial Cells
-function: produce androgens
Sperm Production
- sex cells (gametes) created by MEIOSIS
- end result of meiosis: 4 cells produced, each w/23 chromosomes only!
- Meiosis I: DNA replicated and homologous chromosomes split (haploid at end) Meiosis II: sister chromatids split forming 4 new haploid cells
Cell Division in Males
-spermatagonia divide by MITOSIS and make primary spermatocytes which divide by MEIOSIS making secondary spermatocytes, divide in MEIOSIS II making spermatids which develop into sperm
Spermatogonia
- 23 pairs of chromosomes (46 total)
- divide by mitosis
- diploid
Primary Spermatocytes
- 23 pairs of chromosome (46 total)
- diploid
- divide by meiosis I
Secondary Spermatocytes
- contain only 23 chromosomes
- haploid
- divide by meiosis II
Spermatids
- immature sperm
- contain only 23 chromosomes
Sperm
- -develop from spermatids
- sperm will shed the cytoplasm from spermatid and develop a head, midpiece, and tail
- sperm then released from sustentacular cell cytoplasm and enter lumen of seminiferous tubule
- look mature but not fully motile
Head of Sperm
- contains DNA
- has acrosome cap which contains digestive enzymes to penetrate oocyte
- no mitochondria in head (all from mom)
Midpiece of Sperm
-contains mitochondria
Tail of Sperm
-moves sperm
Epididymis
- comma-shaped organ located posterior to an don top of testis
- receive sperm from testis
- functions: place where sperm become fully motile and stores sperm until they are ejaculated
Ductus (Vas) Deferens
-18 inch long tube that runs from testis to prostate gland
- part of its travel is within the spermatic cord
- then it enters the abdominopelvic cavity, winds around the bladder, and is found near the prostate gland
ductus deferens will “merge” with the duct in the seminal vesicle to form the ejaculatory duct
Ejaculatory Duct
-each one will empty its contents into the urethra
Accessory Reproductive Glands
- function of these glands: to produce a nutritive, alkaline fluid (seminal fluid) to the sperm
- sperm + seminal fluid = semen
Vasectomy
- both ducti deferens cut and tied in a segment
- sperm not ejaculated but resorbed in to epididymis
- can still ejaculate but only the seminal fluid (not sperm)
Seminal Fluid
- nourishes sperm
- alkaline to neutralize acidity of vagina
Seminal Vesicles
- each lies on posterior wall of bladder
- each has a “duct” that merges with the ductus deferens, to form ejaculatory duct
- produces one part of seminal fluid
Prostate Gland
- single, chestnut-shaped organ
- inferior to bladder
- contains the 1st part of the urethra (prostatic urethra)
- produces another part of seminal fluid
Bulborethral Glands
- each gland is pea-shaped
- lies within urogenital diaphragm
- produces 3rd park of seminal fluid
Penis
- is part of the external genitalia
- two main functions: excretes urine and delivers semen to female reproductive tract
- 3 parts: root, body, glans
Root
-“fixed” end of penis within body
Body (Shaft)
- moveable end
- 3 columns of erectile tissue: fills with blood when aroused, penis becomes erect
- 2 corpora cavernosa: masses of erectile tissue on the top (dorsum) of penis
- corpus spongiosum: erectile tissue underneath
- corpora cavernosa, contains spongy (penile) urethra
Glans
- enlarged tip of penis
- has corpus spongiosum only
- covered with prepuce (foreskin)
Circumcision Pros and Cons
- surgical removal of prepuce
- Pros: less likely to get UTI’s, and penile cancer, reduced risk of acquiring/transmitting STI’s including HIV
- Cons: possible pain during procedure, surgical complications can happen, possible reduction of sensations during sexual intercourse
Erection
- penis becomes rigid
- erectile tissue fills with blood and enlarges
- stimulated by parasympathetic division of ANS
Ejactulation
- expulsion of semen from penis
- stimulated by sympathetic division of ANS
Mnemonic
- Point and Shoot
- P=parasympathetic
- S=sympathetic
Seminiferous Tubules
-a tightly coiled structure, where sperm are produced
