Male Reproductive System 19-2 Flashcards
What are the accessory sex glands for the male reproductive system?
- Seminal vesicles
- Prostate
- Bulbourethral glands
What are the system of ducts that makes up the male reproductive system?
- Epididymis
- Ductus deferens
- Ejaculatory ducts
- Urethra
What are the supporting structures of the male reproductive system?
- Scrotum
- Penis
What organs make up the male reproductive system?
System of ducts:
Accessory sex glands:
Supporting structures:
- Testes
- System of ducts: epididymis, ductus deferens, ejaculatory ducts, and urethra
- Accessory sex glands: seminal vesicles, prostate, and bulbourethral glands
- Supporting structures: scrotum and penis
What does semen consist of?
- sperm plus secretions provided by accessory sex glands (seminal vesicles, prostate, bulbourethral gland)
How is sperm transported, stored, helped to mature, and conveyed to the exterior?
- by a system of ducts
What is the dense white fibrous capsule that extends inward and divides each testis into internal compartments?
- lobules
What type of cells line the seminiferous tubules?
- spermatogenic cells
What part of the testes is responsible for producing sperm?
- seminiferous tubules
Which cells in the testes are responsible for releasing the hormone inhibin?
- Sertoli cells
Which cells in the testes are responsible for supporting, protecting, and nourishing spermatogenic cells?
- sertoli cells
Which cells in the testes are responsible for phagocytizing degenerating spermatogenic cells?
- sertoli cells
Which cells in the testes are responsible for secreting the hormone testosterone?
- leydig cells
Which hormone promotes the development of masculine characteristics?
- androgen
Which hormone promotes a man’s libido (sex drive)?
- testosterone
What is the pouch that supports the testes called?
- scrotum
what does the scrotum consist of?
- loose skin
- superficial fascia
- smooth muscle
What divides the scrotum into two sacs?
- septum
How many degrees below normal body temperature is required for optimal production and survival of sperm?
2 - 3 degrees C
How is the scrotum able to maintain the temperature requirements for sperm production?
- because it is outside of the pelvic cavity
What is spermatogennesis?
- the process by which the seminiferous tubules of the testes produce sperm
What are the three stages of spermatogenesis?
- stage 1: meiosis I
- stage 2: meiosis II
- spermiogenesis
What are diploid cells?
- somatic cells containing TWO sets of chromosomes
How does gametes differ from somatic cells (diploid)?
- gametes contain a SINGLE set of chromosomes (haploid)
When does spermatogenesis begins?
- during puberty and continues throughout life
How long does it take for the onset of cell division to the time sperm is released into the lumen of a seminiferous tubule?
- 65 to 75 days
In which stage of spermatogenesis is there no further further replication of DNA?
- meiosis II
When does DNA replication occurs?
- interphase
What are the haploid cells formed during meiosis Ii called?
- spermatids
How much sperm is produced daily?
- 300 million
Most sperm die within how many hours after ejaculation into the female reproductive tract?
- do not survive more than 48 hours
What is the major part of the sperm cell?
- head
- tail
What portion of the sperm contains the nuclear material (DNA) and acrosome?
- head
What enzyme aids in penetration by the sperm into a secondary oocyte?
- acrosome
What are the 4 parts of the tail of the sperm?
- neck
- middle piece
- principal piece
- end piece
What portion of the tail of the sperm contains mitochondria?
- middle piece
What is the longest portion of the sperm tail?
- principal piece
What provides ATP for locomotion of the sperm?
- mitochondria
Where is the site of sperm maturation?
- ductus epididymis
How long can sperm remain in the ductus epididymis for storage?
- several months
Where is the main location for the storage of sperm?
- epididymis
How many muscle layers make up the ductus (vas) deferens?
- made up of a heavy coat of 3 muscle layers
What structures come together to form the ejaculatory duct?
- the ductus (vas) deferens and seminal vesicles
What is responsible for carrying sperm into the urethra?
- ejaculatory duct
What is the terminal duct of the male reproductive system?
- urethra
What does the urethra pass through in males?
- prostate
- deep perineal muscles
- penis
What is responsible for secreting most of the liquid portion of semen?
- accessory sex glands
What secretes an alkaline, viscous fluid that contains fructose, prostaglandin, and clotting proteins?
- seminal vesicles
What does seminal vesicles fluid consist of?
- fructose
- prostaglandins
- clotting proteins
What helps neutralize the acidic environment of the male urethra and female reproductive tract?
- the alkaline nature of the seminal vesicle fluid
What is used for ATP production by the sperm?
- fructose
What contributes to sperm motility and viability and may also stimulate muscular contractions within the female reproductive tract?
- prostaglandins
What helps semen coagulate after ejaculation?
- clotting protein
What volume of semen does seminal vesicle fluid make up?
- 60%
At what age does further enlargement of the prostate occur?
- about 45
The prostate slowly increases in size from __________ to __________ and then it expands rapidly.
- birth
- puberty
What is described as a single donut shaped gland that is about the size of a golf ball?
- prostate
What does the prostate secrete?
- a milky slightly acidic fluid that contains citric acid, acid phosphate, and several protein digesting enzymes
Which fluid secreted by the accessory sex gland is alkaline?
- seminal vesicles
Which fluid secreted by the accessory sex gland is slightly acidic?
- prostatic fluid
What is the pH of prostate fluid?
- 6.5
What percentage of prostatic secretions make up the volume of semen?
- 25%
How big are the bulbourethral glands?
- about the size of peas
What is responsible for secreting an alkaline substance into the urethra during sexual arousal?
- bulbourethral glands
What gland secretes mucus that lubricates the end of the penis and the lining of the urethra?
- bulbourethral glands
What is semen a mixture of?
- sperm
- seminal vesicles secretion
- prostate secretion
- bulbourethral secretion
What is the volume of semen in a typical ejaculation?
- 2.5 to 5 mL
How much sperm is in a mL of semen?
- 50 to 150 million sperm per/mL
What value must sperm be for males to be classified as infertile?
- below 20 million per mL
What is the pH of semen?
- slightly alkaline pH of 7.2 to 7.7
What gives semen a milky appearance?
- prostatic secretions
What gives semen a sticky consistency?
- fluid from the seminal vesicles and bulbourethral glands
What 3 sections make up the penis?
- root
- body
- glans penis
What is the attached portion of the penis?
- the root
What 3 cylindrical masses of tissue makes up the body of the penis?
- 2 dorsolateral masses: CORPORA CAVERNOSA
- 1 CORPUS SPONGIOSUM
Which mass of tissue found in the body of the penis contains the urethra?
- corpus spongiosum
What is the distal end of the corpus spongiosum known as?
- glans penis
What covers the glans penis in an uncircumcised penis?
- prepuce or foreskin
What type of reflex is ejaculation?
- a sympathetic reflex coordinated by the lumbar portion of the spinal cord
Where is gonadotropin releasing hormone GnRH secreted from?
- from the neurotransmitter cells located in the hypothalamus
When does the increase in GnRH secretion takes place?
- at the onset of puberty
Where is the luteinizing hormone (LH) and follicle stimulating hormone (FSH) secreted from?
- anterior pituitary gland
What hormone stimulates the anterior pituitary gland to secrete LH and FSH?
- GnRH
What steroid hormone is synthesized from cholesterol in the testes?
- testosterone
What cells are stimulated by luteinizing hormone (LH) to secrete testosterone?
- leydig cells
What is the principal androgen?
- testosterone
What is responsible for converting testosterone to dihydrotestosterone (DHT)?
- an enzyme in some target cells
What two things are required to stimulate spermatogenesis?
- FSH and testosterone
What hormone is responsible for the development of male reproductive system ducts and the descent of the testes during prenatal development (before birth)?
- testosterone
What hormone is responsible for stimulating the development of the external genitals?
- dihydrotestosterone (DHT)
Where in the body is testosterone converted to estrogen?
- the brain
When does testosterone and DHT bring about the development and enlargement of male sex organs?
- at puberty
When does the development of masculine secondary characteristics take place?
- at puberty
List some examples of masculine secondary characteristics that develops at puberty?
- muscular and skeletal growth
- wide shoulders
- narrow hips
- pubic, axillary, facial, and chest hair
- thickening of the skin
- increased sebaceous gland secretions
- enlargement of the larynx
- deepening of the voice
What type of hormone stimulate protein synthesis?
- anabolic hormones
What is an example of an anabolic hormone?
- androgens (DHT and testosterone)
- *meaning they stimulate protein synthesis**
What hormone plays a role in the development of certain regions of the brain in males?
- estrogen