STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE MALE REPRODUCTIVE SYSTEM Flashcards
What is a system of ducts consisting of the epididymis, ductus deferens, ejaculatory ducts and urethra?
Testes
What are the accessory sex glands?
- Seminal vesicles
- Prostate
- Bulbourethral glands
What are paired oval glands that develop and produce sperm and secrete hormones?
The testes
What are dense white fibrous capsules that extend inward and divide each testis into terminal compartments?
Lobules
What produces sperm by a process called spermatogenesis and is lined with spermatogenic cells?
Seminiferous Tubules
What is located between the developing sperm cells in the seminiferous tubules, support, protect, and nourish spermatogenic cells; phagocytize degenerating spermatogenic cells; secrete fluid for sperm transport; and release of the hormone inhibin, which regulate sperm production?
Sertoli cells
What cells are located between the seminiferous tubules, these cells secrete the hormone testosterone?
Leydig cells
What hormone promotes the development of masculine characteristics?
Androgen
What hormone promotes a man libido?
Testosterone
What is known as a pouch that supports the testes and consists of loose skin, superficial fascia, and smooth muscle?
Scrotum
True or False
The production and survival of sperm is optimal at a temperature that is about 2-3 degrees Celsius above normal body temperature
False
The production and survival of sperm is optimal at a temperature that is about 2-3 degrees celsius BELOW normal body temperature
What is the process by which the seminiferous tubules of the testes produce sperm?
Spermatogenesis
What are the three stages of spermatogenesis?
- Meiosis I
- Meiosis II
- Spermiogenesis
What are diploid cells?
Somatic cells that contain two sets of chromosomes
True or false
Gametes differ from somatic cells because they only contain a single set of 23 chromosomes (Haploid)
True
The time from onset of cell division in a spermatogonium until sperm are released into the lumen of a seminiferous tubule is how long?
65-75 days
True or False
Spermatogonia contain the diploid number of chromosomes (46)
True
Are spermatocytes diploid like spermatogonia?
Yes
What is the net effect of meiosis I?
Each resulting cell contains a haploid set of chromosomes
What are the cells formed by meiosis I?
haploid secondary spermatocytes (23 (replicated) chromosomes)
Each chromosome within a secondary spermatocyte is made up of what?
Two chromatids (two copies of DNA) still attached by a centromere
Is there further DNA replication in Meiosis II?
No
What are the cells formed from meiosis II that contain 23 chromosomes, each of which is composed of a single chromatid?
spermatids
What is the final stage of spermatogenesis in which each haploid spermatid develops into a single sperm cell?
Spermiogenesis
Sperm are produced at the rate of about what per day?
300 million per day
Once ejaculated how long do sperm survive in the female reproductive tract?
no more than 48 hours
What part of the sperm contains DNA and an acrosome?
The head
What is a vesicle containing enzymes that aid in the penetration by the sperm into the secondary oocyte?
Acrosome
The tail of the sperm is subdivided into what four parts?
- neck
- middle piece
- principal piece
- end piece
What part of the sperms tail contains mitochondria that provide ATP for locomotion?
middle piece
What is the longest portion of the sperms tail?
Principal piece
True or False
Following spermatogensis, pressure generated by the continual release of sperm and fluid secreted by sustentacular cells propel sperm and fluid through the seminiferous tubules and into the epididymis
True
What is a comma-shaped organ that lies along the posterior border of the testis?
Epididymis
What is the site of sperm maturation?
Ductus epididymis
The ductus epididymis also stores and helps propel sperm during sexual arousal into the what?
Ductus vas deferens
How long does it normally take for sperm to gain motility?
10-14 days
Beyond the epididymis, the duct is termed what?
Ductus deferens or vas deferens
What has a heavy coat of three layers of muscle and stores sperm, which can remain viable for up to several months?
ductus deferens
What is the supporting structure of the male reproductive system?
Spermatic cord
What are formed by the union of the duct from the ductus deferens and the seminal vesicles?
Ejaculatory ducts
What is the terminal duct of the male reproductive system, serving as a passageway for both sperm and urine?
Urethra
In the male, the urethra passes through where?
- prostate
- deep perineal muscles
- penis
The opening of the urethra to the exterior is called the what?
External urethral orifice
What are pouch-like structures, lying posterior to the base of the urinary bladder and anterior to the rectum?
Seminal vesicles
True or False
The alkaline nature of the fluid secreted by seminal vesicles helps to neutralize the acidic environment of the male urethra and female reproductive tract that otherwise would inactivate and kill sperm
True
What is used for ATP production by sperm?
Fructose
What contributes to sperm motility and viability and may also stimulate muscular contraction within the female reproductive tract?
Prostaglandins
What helps semen coagulate after ejaculation?
Clotting proteins
Fluids secreted by the seminal vesicles normally constitute about what percentage of the volume of semen?
60%
What is a single, doughnut-shaped gland about the size of a golf ball?
The prostate
Prostatic secretions make up about what percentage of the volume of semen?
25%
What are located inferior to the prostate on either side of the urethra and during sexual arousal secrete an alkaline substance into the urethra that protects the passing sperm by neutralizing acids from urine in the urethra?
Bulbourethral glands
Semen is a mixture of sperm and the secretions of what?
- seminal vesicles
- prostate
- bulbourethral glands
What is the volume of semen in a typical ejaculation?
2.5-5 mL, with 50-150 million sperm per mL
When the number of sperm per mL falls below what does it indicate possible male infertility?
20 million per mL
What is the typical pH of semen?
7.2-7.7
What gives semen a milky appearance and fluids from where give it a sticky consistency?
- Prostatic secretions
2. seminal vesicles and bulbourethral glands
What is cylindrical in shape and consists of a root, a body, and the glans penis?
Penis
What is the attached portion of the penis?
Root
The two dorsolateral masses of tissue of the body of the penis are called what?
Copora cavernosa penis
What is the smaller midventral mass of tissue in the penis that contains the urethra?
corpus spongiosum penis
What is the slightly enlarged region of the penis at the distal end of the corpus spongiosum?
Glans penis
What covers the glans in an uncircumcised penis?
loosely fitting prepuce (foreskin)
What impulses cause release of neurotransmitters and local hormones, including the gas nitric oxide, which relaxes vascular smooth muscle in the penile arteries?
Parasympathetic impulses
Ejaculation is a sympathetic reflex that is coordinated by what?
lumbar portion of the spinal cord
At the onset of puberty, neurosecretory cells in the hypothalamus increase their secretion of what?
Gonadtropin-releasing hormone (GnRH)
GnRH stimulates the anterior pituitary to increase the secretion of what?
- Luteinizing hormone (LH)
2. Follicle-stimulating hormone (FSH)
LH stimulates Leydig cells, which are located between the seminiferous tubules, to secrete the hormone what?
Testosterone
What is testosterone synthesized from?
Cholesterol in the testes
What is the principal androgen in males?
Testosterone
In some target cells, such as those in the external genitals and prostate, an enzyme converts testosterone to another androgen called what?
Dihydrotestosterone (DHT)
What two hormones act together to stimulate spermatogenesis?
- FSH
2. Testosterone
Once the degree of spermatogenesis required for male reproductive functions has been achieved, what cells release inhibin, a hormone named for its inhibition of FSH secretion by the anterior pituitary?
Sertoli cells
What does inhibin do?
Inhibits the secretion of hormones needed for spermatogenesis
Before birth, what stimulates the male pattern of development of reproductive system ducts and the descent of testes?
Testosterone
What stimulates the development of external genitals?
DHT
Testosterone is also converted in the brain to what, which may play a role in the development of certain regions of the brain in males?
Estrogens (feminizing hormones)
At puberty, what hormones bring about development and enlargement of the male sex organs and the development of masculine secondary sexual characteristics?
Testosterone and DHT
What contribute to male sexual behavior and spermatogenesis and to sex drive (libido) in both males and females?
Androgens
Androgens are anabolic hormones; that is, they stimulate what?
Protein synthesis