A&P of Male Reproductive System Flashcards
What are the organs of the male reproductive system?
- Testes
- Accessory sex glands
- Several supporting structures
What structures are included within the testes?
- Epididymis
- Ductus deferens (vas deferens)
- Ejaculatory ducts
- Urethra
What are the accessory sex glands of the male reproductive system?
- Seminal Vesicles
- Prostate
- Bulbourethral glands
What are the testes?
Paired oval glands that develop sperm and secrete hormones
What are the structures/hormones within the testes?
- Lobules
- Seminiferous tubules
- Sertoli cells
- Leydig cells
- Androgen
- Testosterone
What in the lobules extend inward and divides each testis into internal compartments?
Dense white fibrous capsule
What structure produces sperm?
Seminiferous tubules
What is the process to produce sperm?
Spermatogenesis
What cells secrete testosterone and where is that structure located?
- Leydig cells
- located between sertoli cells
What do sertoli cells produce?
- Support, protect, and nourish spermatogenic cells
- Phagocytize degenerating spermatogenic cells
- Secrete fluid for transport
- Release hormone inhibin
What is the hormone that promotes development of masculine characteristics?
Androgen
What promotes a man’s libido?
Testosterone
What are some key characteristics of the scrotum?
- Pouch that supports the testes
- Septum divides scrotum into two sacks
What is the optimal temperature for the production and survival of sperm?
About 2-3 degrees Celsius below normal body temperature
What are the three stages of spermatogenesis?
- Meiosis I
- Meiosis II
- Spermiogenesis
What are diploid cells?
Somatic cells that contain two sets of chromosomes
When does Spermatogenesis begin?
- Begins during puberty and continues throughout life
- Contain diploid number of chromosomes (46)
What is the timeframe from on-set of cell division of spermatogonium until sperm are released into lumen of seminiferous tubule?
65-75 days
After spermatogonium undergo mitosis, where does one cell stay?
Near the basement membrane as spermatogonium
- stem cells remain for mitosis
What does meiosis I begin and end with?
- Begins with diploid starting cell
- Ends with 2 cells with haploid number of chromosomes
What happens during meiosis II?
Each of the two haploid cells from meiosis I divide
What are spermatids?
Haploid cells formed during meiosis II
What happens during spermiogenesis?
Haploid spermatid develops into single cell
What rate are sperm produced and how long can they last?
- Rate of 300 million/day
- After ejaculated, lasts 48 hours in female reproductive tract
What are the major parts of a sperm cell?
- Head
- Tail
What does the head of a sperm cell contain?
- Nuclear material (DNA)
- Acrosome
What is acrosome?
A vesicle containing enzymes that aid penetration by the sperm cell into a secondary oocyte
The tail of a sperm cell is subdivided into what four parts?
- Neck
- Middle piece
- Principle piece
- End piece
What does the middle piece of the tail of a sperm cell contain?
Mitochondria that contain ATP for locomotion
What is the longest portion of the tail of a sperm cell?
Principle piece
What is the epididymis?
- Comma shaped organ that lies posterior border of the testis
- Mostly of tightly coiled ductus epididymis
What is the site of sperm maturation?
Ductus epididymis
What does the ductus epididymis do?
- Store sperm
- Propel sperm during into vas deferens
- May remain in storage for several months
The vas deferens has a heavy coat with how many layers of muscle?
Three
In addition to storing sperm, the vas deferens does what?
Conveys sperm from epididymis toward urethra during sexual arousal by peristaltic contractions of the muscular coat
What is the supporting structure of the male reproductive system?
Spermatic cord
What is formed by a union of the duct from the vas deferens and seminal vesicles?
Ejaculatory ducts
What does the urethra pass through?
- Prostate
- Deep perineal muscles
- Penis
What are seminal vesicles?
Pouch-like structures lying posterior to the base of the urinary bladder and anterior to the rectum
What do the seminal vesicles secrete?
Alkaline, viscous fluid that contains fructose, prostaglandins, and clotting proteins
What helps neutralize the acidic environment of the male urethra and female reproductive tract?
The alkaline nature of the fluid secreted from the seminal vesicles
What contributes to sperm motility and viability?
Prostaglandins
What helps the semen coagulate after ejaculation?
Clotting proteins
What does the prostate secrete?
Milky, slightly acidic fluid (pH 6.5) that contains citric acid, acid phosphatase, and several protein-digesting enzymes (such as PSA)
What are some percentages that make up semen?
- About 60% secreted from seminal vesicles
- About 25% secreted from prostate
What are some characteristics of bulbourethral glands?
- Paired about size of peas
- Located inferior to prostate on either side of urethra
- Secrete alkaline urethra that protects passing sperm from acids
- Secrete mucus to prevent sperm damage during ejaculation
What is semen?
Mixture of secretions of seminal vesicles, prostate, and bulbourethral glands
What is the volume of semen in a typical ejaculation?
- 2.5-5 mL
- 50-150 million sperm/mL
- <20 million sperm/mL equals infertile
What is the pH of sperm?
7.2-7.7
Does semen contain an antibiotic that can destroy certain bacteria?
Yes
The body of the penis is composed of what?
Three cylindrical mases of tissue
What are the two dorsolateral masses of tissue of the penis called?
Corpora cavernosa penis
What is the smaller midventral mass of tissue of the penis called?
Corpus Spongiosum penis, contains the urethra
At the onset of puberty, the hypothalamus increase their secretion of what hormone?
Gonadotropin-releasing hormone (GnRH)
What does Gonadotropin-releasing hormone (GnRH) stimulate the anterior pituitary to secrete?
- Luteinizing hormone (LH)
- Follicle-stimulating hormone (FSH)
What does Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) and negative feedback cycles control?
Leydig and Sertoli cells of the testes
- Stimulate spermatogenesis
LH stimulates Leydig cells to secrete what hormone?
Testosterone
What acts together to stimulate spermatogenesis?
Follicle-stimulating hormone (FSH) and testosterone
What inhibits the secretion of hormones needed for spermatogenesis?
Inhibin
What stimulates the development of external genitalia?
Dihydrotestosterone
What are anabolic hormones that stimulate protein synthesis?
Anabolic hormones
