Reproductive System Flashcards
In males, the primary sex organs are the…
testes
What are the accessory reproductive organs of the male?
ducts, accessory glands
What is the male organ of copulation?
the penis
Major functions of the male and female reproductive systems
produce sex cells (gametes) and sex hormones
- primary sex organs are the gonads, which produce the primary sex cells (gametes)
Where are the testes?
within the scrotum
What is the scrotum?
an outgrowth of the abdominal wall that holds the testes
Why are the testes located in the scrotum?
it keeps them cooler than the core body temperature
Each testis is attached to a _________ _____, containing the vas (ductus) deferens, testicular artery, and pampiniform plexus of veins
spermatic cord
The structures of the spermatic cord pass through the…
inguinal canal
The testicular arteries, which arise from the _________ ______, deliver arterial blood to the testes
abdominal aorta
What drains venous blood from the testis to the testicular vein?
the pampiniform plexus
The right testicular vein empties into the….
inferior vena cava
The left testicular vein empties into the…
left renal vein
What helps cool the testes by drawing heat from the testicular artery?
the pampiniform plexus
This muscle, located on the surface of the testis and spermatic cord, also helps to regulate the temperature of the testes by contracting and relaxing.
cremaster muscle
What structure carries sperm cells into thet pelvis to be added to seminal secretions (from seminal vesicle and prostate gland) at the time of ejaculation?
the vas (ductus) deferens
What artery courses over the left renal vein?
superior mesenteric artery
What happens if there is increased pressure on the left renal vein?
pressure increased in the left testicular vein
What happens if pressure in the left testicular vein increases?
the pampiniform plexus of veins can form varicosities = variococele
Testes develop from __________ tissue in the posterior abdominal wall, next to the mesonephros
gonadal
When the mesonephros degenerate, testes acquire the…
mesonephric ducts
________ is a cord of tissue that guides the testes down through the inguinal canal and into the scrotum
gubernaculum
The mesonephric duct gives rise to…
efferent ductules, vas deferens, and seminal vesicles
The passage of the gonads through the inguinal canal makes males more susceptible to…
inguinal herniation
Testes
the male gonads
Function of the testes
produce the male gametes (sperm cells) and sex hormones
What encapsulates the testes?
a whitish tunica albugenia
Testes are filled with highly coiled tubules called…
seminiferous tubules
Sperm cells develop within the __________ ________ during spermatogenesis
seminiferous tubules
Once developed, sperm cells move into the…
rete testis
From the rete testis, sperm cells move through the….
efferent ductules
From the efferent ductules, sperm cells move to the…
epididymis (to learn how to achieve full motility: “swim school”)
What is the anatomical position of the penis?
when it is erect
- facing stomach = dorsal/posterior
- facing testes = anterior/ventral
Spermatogenesis
process of sperm cell development within the seminiferous tubules
When does spermatogenesis begin?
at the time of puberty, when the hypothalamus produces gonadotropin-releasing hormone
What is the goal of spermatogenesis?
reduce the chromosome number of the sperm cells to 23 (haploid) so that they can combine with 23 chromosomes from an egg to produce a cell with 46 chromosomes (diploid)
At the time of birth, the testes contain primitive sperm cells called…
spermatogonia
How many chromosomes do the sermatogonia have?
23 pairs (46 total)
At the time of puberty, sperm cells undergo what changes?
- spermatogonia undergo mitosis, producing two daughter cells (each with 46 chromosomes). one of the daughter cells acts like a new spermatogonium (to undergo mitosis again), while the other is a committed cell called a primary spermatocyte.
- the primary spermatocyte has 23 pairs of chromosomes (46 total). each chromosome initially exists in the form of a single chromatid (a total of 46 chromatids)
- the primary spermatocyte then undergoes replication (the DNA replicates) such that each chromosome exists in the form of sister chromaids. therefore, after rreplicaiton the primary spermatocyte has 46 chromosmes and each chromosome has 2 chromatids (92 chromatids total)
- the first meiotic division occurs. the pairs of chromosomes separate and one from each pair goes to a separate secondary spermatocyte. each of the chromosomes still have sister chromatids so each secondary spermatocyte has 23 chromosomes (haploid), with each consisting of 2 chromatids (46 chromatids total)
- the second meiotic division occurs. the sister chromatids from each shromosome separate, each going to separate spermatids. each of the chromosomes in the spermatids consist of single chromatids. so each chromatid has 23 chromosomes (haploid) and each chromosome consists of a single chromatid (23 chromatids total). the cells now have the correct amoutn of genetic material to combine with the 23 chromosomes in an egg to restore the chromosome number to 46 (23 pairs). however, the spermatids much first undergo spermiogenesis.
Spermatogenesis occurs…
within the walls of the seminiferous tubules
As the sperm cells pass towards the lumen, they pass between…
large sustentacular (Sertoli) cells
The sustentacular (Sertoli) cells assist with sperm development by…
providing a protective environment and nutritional support (they also release the hormone inhibin when sperm count is high)
Interstitial cells (of Leydig) produce…
androgens (testosterone) which cause males to develop characteristics such as body hair distribution, lower voice, and sperm production.
NOTE: the adrenal cortex also produces androgens
The tunica albuginea has ______ that separate each testis into _______
septa ; lobules
Spermiogenesis
prepares spermatids physically to fertilize an ovum
Steps of Spermiogenesis:
- shed most of their cytoplasm
- develop an acrosome cap around the nucleus
- develop a flagellum (tail)
- condense mitochondria in the midpiece area
Where do sperm cells go when they complete spermiogenesis?
they pass into the rete testis, through the efferent ductules, and to the epididymis so that they may achieve full motility.
Sperm cells travel through what during ejaculation?
vas (ductus) deferens
How do sperm cells move from the vas (ductus) deferens into the pelvis?
strong muscular contractions
What do sperm cells do in the pelvis?
mix with secretions from the seminal vesicles and prostate gland
Where are seminal vesicles found?
along the posterior surface of the bladder (lateral to ampulla of vas deferens)
The seminal vesicle joins the vas (ductus) deferens to form the…
ejaculatory duct, which penetrates the prostate gland
What do the seminal vesicles secrete into semen?
fructose: energy supply for sperm cells
prostaglandins: promote dilation of cervical canal
bicarbonate: buffers acidic environment
Vericocele
enlargement of scrotal veins
- may or may not cause infertility
Is the prostate gland superior or inferior to the bladder?
just inferior
The prostatic urethra conveys…
urine and seminal fluid
The prostate gland secretes a milky fluid which contains:
citric acid: nutrient for sperm health
seminalplasmin: antibiotic to combat UTIs
prostate specific antigen (PSA): liquefies semen after ejaculation (indicator of prostate cancer)
Prostate Cancer
- most common malignancy in men >50 years
- risk increases with age, family history, color, and obesity
- early stages are generally asymptomatic
- can metastasize to other parts of body if left untreated
Benign Prostatic Hyperplasia (BPH)
- non cancerous enlargement of the prostate gland
- tends to compress prostatic urethra (urethra has to pass thru the prostate gland)
Bulbourethral Glands
paired, pea-shaped glands distal to prostate gland
What do the bulbourethral glands secrete?
a clear, mucus-like substance that conditions the urethra prior to ejaculation
What is the male copulatory organ?
the penis
The penis is composed of…
highly vascular erectile tissue that becomes engorged with blood during sexual arousal
Two crura, attached to the ischiopubic rami, merge at the pubic symphysis to form the…
corpora cavernosa
The bulb of the penis, supported by the perineal membrane and perineal body, join the corpora cavernosa to form the…
corpus spongiosum
What can pass through the perineal membrane?
urethra
The end of the corpus spongiosum expands to form the…
glans penis
The penile urethra passes through the…
spongy erectile tissue
The spongy and cavernous erectile tissue cylinders are encapsulated by…
tunica albuginea (but is much thicker around cavernous tissue)
Tunica albuginea is surrounded by the…
deep fascia of the penis (Buck’s fascia), which is surrounded by skin
Ischiocernosus muscle is located on the…
crura
Bulbospongiosus muscle is located on the….
bulb
The bulbospongiosus muscle helps…
compress veins to maintain erection
What consists of the body of the penis?
corpora cavernosa
corpus spongiosum
What consists of the root of the penis?
crura
bulb
What allows for an erection?
straightening of penile vessels, allowing blood to enter the penis
The autonomic nervous system innervates penile smooth muscle related to…
sexual activity
The smooth muscle of the vas deferens is innervated by which system?
sympathetic
Which nervous system dilates the blood vessels of the erectile tissue so that they can receive more blood?
parasympathetic
The parasympathetics to the erectile tissues come from which levels of the spinal cord?
S2 - S4
The parasympathetics to the penis travel down into the ____________ before exiting under the _________.
flood of the pelvis (outside the prostate gland) ; pubic arch
Sensation form the penis is carried by the ________ nerve, a somatic nerve from S2 - S4 levels of the spinal cord
pudendal
The pudendal nerve also has a (somatic) motor component to the..
external urethral sphincter and external anal sphincter
The parasympathetics and sympathetics from S2, S3, and S4 form an…
autonomic plexus
The pudendal nerve leaves the pelvis posteriorly, travels medial to the ______ (on either side) to reach the ______,
ischium ; perineum
What does the phrase “point and shoot” refer to?
Point - parasympathetics, erection
Shoot - sympathetics, ejaculate
The internal pudendal artery originates in the pelvis as one of the branches of which artery?
internal iliac artery
The internal pudendal artery travels with the pudendal nerve out of the pelvis in the _________ and then anteriorly to the ________.
deep gluteal region ; perineum
What does the internal pudendal artery supply blood to?
erectile tissues as well as other tissues of the perineum
Compression of what artery can reduce erection even when the nerves are intact?
internal pudendal artery
