Male Reproductive System Flashcards
Organs of the male reproductive system
Teste
Accessory Sex Glands (seminal vesicle, prostate, and bulbourethral glands)
Scrotum
Penis
What are paired oval glands that develop, produce sperm and secrete hormones.
Testes
How are sperm transported, stored, matured, and conveyed to the exterior?
By a system of ducts.
What does semen contain?
Sperm plus the secretions provided by the accessory sex glands.
What are lobules?
Dense White Fibrous Capsule that extends inward and divides each testis into internal compartments.
What are the seminiferous tubules?
Produce sperm by a process called spermatogenesis. Tubule is lined with spermatogenic cells.
What do the Sertoli cells do?
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
Release of the hormone inhibin, which regulate sperm production
Where are the Leydig cells located?
Between the seminiferous tubules.
What do the leydig cells do?
Secrete the hormone testosterone.
What is the hormone that promotes the development of masculine characteristics?
Androgen
What promotes a mans libido?
Testosterone
What is a pouch that supports the testes; it consists of loose skin, superficial fascia, and smooth muscle?
The Scrotum
What divides the scrotum into two sacs each containing a single testis?
Septum
The production and survival of sperm is optimal at what temperature?
2-3 degrees Celsius below normal body temperature.
What is Spermatogenesis?
The process by which the seminiferous tubules of the testes produce sperm.
How many stages are there of spermatogenesis, and what are they?
3 stages
Meiosis I, Meiosis II, Spermiogensis
What are diploid cells?
Diploid cells are somatic cells that contain two sets of chromosomes.
What do gametes contain?
Gametes contain a single set of 23 chromosomes.
In sexual reproduction an organism results from what?
The fusion of two different gametes, one from each parent.
Meiosis occurs in how many stages?
Two stages
Meiosis I and Meiosis II
The time from on-set of cell division in a spermatogonium until sperm are re-leased into the lumen of a seminiferous tubule is how many days?
65 to 75 days.
The cells formed by meiosis I are what kind of spermatocytes? Having how many chromosomes?
Haploid secondary spermatocytes,
23 (replicated) chromosomes.
In the final stage of spermatogenesis, what is happening?
Each haploid spermatid develops into a single sperm cell.
Sperm are produced at what rate per day?
The rate of about 300 million per day
Once ejaculated, most do not survive more than how many hours in the female reproductive tract?
48 hours in the female reproductive tract
What are the major parts of the sperm cell?
The head and the tail.
The tail of the sperm are divided into how many parts?
What are the parts?
Divided into four parts
Neck, Middle Piece, Principal Piece, End Piece.
Which piece of the tail of sperm contains mitochondria which provides ATP for locomotion?
The middle piece.
What is the longest portion of the tail?
The principal piece is the longest portion.
What is the terminal, tapering portion of the tail?
The end piece.
What is a comma-shaped organ that lies along the posterior border of the testis?
The epididymis
What does the epididymis contain?
Each epididymis consists mostly of the tightly coiled ductus epididymis.
What is the site of sperm maturation?
The epididymis.
What is sperm maturation?
The process by which sperm acquire motility and the ability to fertilize a secondary oocyte.
What also stores sperm and helps propel them during sexual arousal by peristaltic contraction of its smooth muscle into the ductus vas deferens?
The ductus epididymis
What ascends along the posterior border of the epididymis and
penetrates the inguinal canal, a passageway in the front abdominal wall?
The ductus deferens
Functionally, the ductus deferens do what? stores sperm, which can remain viable here for up to
several months.
Stores sperm, which can remain viable here for up to
several months.
What is a supporting structure of the male reproductive system?
Spermatic Cord
How are the ejaculatory ducts formed?
Formed by the union of the duct from the vas deferens to the seminal vesicles.
(c) The ductus deferens has a heavy coat of what?
Three layers of muscle.
What is the terminal duct of the male reproductive system, serving as a passageway
for both sperm and urine?
The urethra
In the male, the urethra passes through what ?
The prostate, deep perineal muscles and penis
The opening of the urethra to the exterior is called what?
External urethral orifice
What secretes most of the liquid portion of semen?
Accessory sex glands
What are pouch-like structures, lying posterior to the base of the urinary
bladder and anterior to the rectum?
Seminal vesicles
What do the seminal vesicles secrete?
Secrete an alkaline, viscous fluid that contains fructose,
prostaglandins, and clotting proteins.
The alkaline nature of the seminal vesicle fluid helps to do what?
To neutralize the acidic environment of the male
urethra and female reproductive tract that otherwise would inactivate and kill sperm
The fructose is used for what?
ATP production by sperm
Prostaglandins contribute to what?
Sperm motility and viability and may also stimulate
muscular contraction within the female reproductive tract.
Fluid secreted by the seminal
vesicles normally constitutes about percentage of the volume of semen?
60% of the volume of semen.
Clotting proteins help what?
Semen coagulate after ejaculation
What is a single, doughnut-shaped gland about the size of a golf ball?
The prostate
What is inferior to the urinary bladder and surrounds the upper portion of the urethra?
The prostate
What secretes a milky, slightly acidic fluid?
The prostate
Prostatic secretions make up about what percentage of the volume of semen?
25% of the volume of semen
The paired bulbourethral glands are about what size?
The size of peas
Where are the bulbourethral glands located?
They are located inferior to the prostate on either side of the urethra.
During sexual arousal, the bulbourethral glands secrete an alkaline substance into the
urethra glands that does what?
That protects the passing
sperm by neutralizing acids from urine in the urethra.
What do the bulbourethral glands secrete?
They secrete mucus that lubricates the end of the penis and the lining of the urethra,
thereby decreasing the number of sperm damaged during ejaculation.
Semen is a mixture of what?
Mixture of sperm and the secretions of the seminal vesicles, prostate, and
bulbourethral glands.
The volume of semen in a typical ejaculation is what?
2.5 to 5 milliliters, with 50 to 150
million sperm per milliliter.
When the number of sperm falls below the male is likely to be
infertile?
20 million per milliliter,
semen has a slightly alkaline pH of?
Semen has a slightly alkaline pH of 7.2 to 7.7
Prostatic secretion gives semen what kind of appearance?
A milky appearance
Fluids from the seminal
vesicles and bulbourethral glands give semen what kind of consistency?
Give it a sticky consistency.
Semen also contains what that can destroy certain bacteria?
An antibiotic
The antibiotic may help control what? the abundance of naturally occurring bacteria in the
semen and in the lower female reproductive tract.
The abundance of naturally occurring bacteria in the
semen and in the lower female reproductive tract.
What contains the urethra and is a passageway for the ejaculation of semen and the
excretion of urine?
Penis
Describe the penis.
Cylindrical in shape and consists of a root, a body, and the glans penis
The distal end of the corpus spongiosum penis is a slightly enlarged region called what?
Glans penis
Define erection.
The first visible sign of sexual excitement is erection, the enlargement and stiffening
of the penis.
How does an erection happen?
Parasympathetic impulses cause release of neurotransmitters and local hormones,
including the gas nitric oxide, which relaxes vascular smooth muscle in the penile
arteries.
Define ejaculation.
Ejaculation, the powerful release of semen from the urethra to the exterior, is a
sympathetic reflex coordinated by the lumbar portion of the spinal cord
What hormone stimulates the anterior pituitary to increase its secretion of
luteinizing hormone (LH) and follicle-stimulating hormone (FSH)?
Gonadotropin-releasing hormone (GnRH).
LH stimulates Leydig cells, which are located between seminiferous tubules, to secrete
the hormone testosterone
Lutenizing Hormone
This steroid hormone is synthesized from cholesterol in the
testes and is the principal androgen. What hormone is this?
Luteinizing Hormone
What acts in a negative feedback manner to suppress secretion of LH by the
anterior pituitary and to suppress secretion of GnRH by hypothalamic neurosecretory
cells?
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 acts together to stimulate spermatogenesis?
FSH and testosterone act together to stimulate spermatogenesis
Once the degree of spermatogenesis required for male reproductive functions has
been achieved, Sertoli cells releases what hormone, named for its inhibition of
FSH secretion by the anterior pituitary?
inhibin, a hormone named for its inhibition of
FSH secretion
Inhibin thus inhibits what?
The secretion of hormones needed for spermatogenesis
Before birth. what stimulates the male pattern of development of reproductive
system ducts and the descent of the testes?
Testosterone
What stimulates development of the external genitals?
DHT
What contributes to male sexual behavior and spermatogenesis and to sex drive
(libido) in both males and females?
Androgens
Androgens are what kind of hormones?
What do these hormones do?
Androgens are anabolic hormones; that is, they stimulate protein synthesis.
