Lecture 21 - The Male Reproductive System Flashcards
when does the reproductive system become functional?
at puberty
true or false: reproductive hormones can affect the structure and function of other systems
true
what are the three main functions of the male reproductive system?
- produce male gametes (spermatozoa), sex hormones (testosterone), and seminal fluid
- temporary storage for spermatozoa (epididymis)
- delivery of spermatozoa to the female reproductive tract (ducts)
site of production of gametes and sex hormones in males
gonads (testes)
site of sperm storage, maturation, and transportation
epididymis
site of sperm transportation
vas (ductus) deferens
what are the two main parts of the male reproductive tract?
epididymis and vas deferens
accessory gland which supports the maintenance and maturation of sperm
pituitary gland
accessory glands responsible for the production of seminal fluid
seminal vesicles, prostate, and bulbourethral glands
male organ of copulation which is a common pathway for urine and semen via the urethra
penis
separates the abdominal cavity from the pelvic cavity
parietal peritoneum
are the pelvic organs intraperitoneal or retroperitoneal?
retroperitoneal
the pelvic cavity is also known as the:
lesser (true) bony pelvis
the pelvic inlet spans across the:
pelvic brims
the pelvic outlet spans across the:
sacrum, pubic symphysis, and ischial spines
the perineal muscles are all innervated by the:
pudendal nerve (S2-4)
what are the two main types of perineal muscles?
anal and urogenital
what are the urogenital muscles?
muscles that lie over the erectile tissues of genetalia and increases blood flow and help with ejaculation
what are the main anal perineal muscles?
levator ani and external anal sphincter
what are the two main parts of the erectile tissue of the penis?
the corpora cavernosa and the corpus spongiosum
the crus of the penis is:
part of the corpora cavernosa which is attached to the body wall
the ischiocavernosus muscle lies on top of the:
crus of the penis
the bulb of the penis is:
part of the corpus spongiosum which is attached to the scrotum
the bulbospongiosus muscle lies on top of the:
bulb of the penis
what are the three parts of the spermatic cord?
- vas deferens
- pampiniform complex (veins)
- testicular artery
what muscle is associated with the spermatic cord?
the cremaster muscle
separates the two testes
scrotal septum
sits on top of the testis
epididymis
what are the main parts of the scrotum?
- scrotal skin
- scrotal cavity
- testis
- epididymis
semen consists of:
spermatozoa/sperm and seminal fluid (secretions of accessory glands)
site of spermatozoa production
seminiferous tubules (testes)
site of sperm maturation and motility
epididymis
site of sperm transport from the scrotum to the ejaculatory ducts
vas deferens
the primary sex organ in males which produces gametes (sperm) and sex hormones (testosterone)
testis
list the six main parts of the testis:
- tunica vaginalis (parietal and visceral)
- scrotal cavity
- tunica albugenia
- seminiferous tubules
- rete testis
- efferent ductules
what are the three parts of the epididymis?
- head
- body
- tail
highly vascularized fibrous tissue which bulges posteriorly to for the mediastinum of each testis (also where blood, lymph, and nerves enter - similar to a hilum)
tunica albugenia
how many lobules are in each testis?
~250 (separated by septa)
how many seminiferous tubules are in each lobule?
1-4
each seminiferous tubule is ____ long with a diameter of ____
30-80cm, ~150-250um
the seminiferous tubules are embedded in connective tissue with:
blood, lymph, nerves, and interstitial cells
differentiation of spermatagonia into primary spermatocytes
spermatocytogenesis
reduce diploid chromosomal complements to form haploid spermatids (1 germ cell = 4 spermatids)
meiosis
transformation of the four spermatids into spermatozoa (change in shape)
spermiogenesis
germ cells adjacent to the basal lamina (undergo mitosis and meiosis from puberty onwards)
spermatogonia
what are the five main functions of sertoli cells?
- support, protect, and nourish spermatogenic cells
- phagocytosis of excess cytoplasm
- helps maintain necessary testosterone levels
- establish blood-testis barrier
- secrete fructose-rich fluid
spermatogenesis is stimulated by:
testosterone
how do the sertoli cells establish the blood-testis barrier?
through tight junctions between cells
what is the function of the blood-testis barrier?
prevents the attack of sperm from the body’s immune system (sperm proteins might be seen as foreign)
at birth, the testes contain only ______ and _______
spermatogonia, germ cells
the final stage of spermatogenesis
spermiogenesis
what is spermiogenesis?
the transformation of a round spermatid into assymetric spermatozoon
what are the four main processes that occur during spermiogenesis?
1) condensation of the nucleus
2) formation of the acrosome
3) development of the flagellum
4) shedding of cytolplasm (ingested by Sertoli cells)
what is the acrosome?
part of the head of the sperm that contains enzymes that bore a hole in the zona pellucida
what is the purpose of the acrosome?
allows the sperm to reach the plasma membrane of the egg
what is the purpose of the mitochondria in the midpiece of the sperm?
produces ATP that gerenates the beating of the flagellum
interstitial cells are surrounded by:
capillaries and lymphatic vessels (within CT)
what are the two types of interstitial cells?
myoid cells and Leydig cells
contraction of these cells produces rhythmic movements that help propel the contents of the sesminiferous tubules toward the rete testis
myoid cells
round to polygonal shaped cells in the interstitial regions with a large central nucleus; they produce and secrete testosterone at puberty
Leydig cells
- regulates spermatogenesis
- stimulates development and maintenance of male secondary sex characteristics
- stimulate growth and metabolism throughout the body
- influence brain development
these are all functions of:
testosterone
at puberty, the hypothalamus begins to release ______ which regulates the production and release of ______ and ______ from the anterior pituitary gland
GnRH, FSH, LH
stimulates sertoli cells to support spermatogenesis
follicle stimulating hormone (FSH)
stimulates Leydig cells to produce testosterone
luteinizing hormone (LH)
sertoli cells can release ______ to depress the anterior pituitary from producing FSH and LH
inhibin
long coiled duct outside the testis surrounded by loose CT, ~4-5m in length
epididymis
where do sperm gain motility?
the epididymis
where does sperm capacitation occur?
in the female reproductive tract
the simple epithelium in the epididymis is composed of these two types of cells:
tall ciliated cells and short absorpive cells
what is the purpose of the tall ciliated cells in the epididymis?
moves sperm along
what is the purpose of the short absorptive cells in the epididymis?
absorbs everything released by maturing sperm
sperm must pass through the epididymis before becoming:
motile
the epididymis is made of:
simple ciliated epithelium surrounded by layers of smooth muscle
what is the ductus (vas) deferens?
a long and thick muscular tube (3 layers of smooth muscle) which moves sperm from the epididymis to the seminal vesicles via peristaltic contraction
the vas deferens enlarges as an ampulla to join the:
seminal vesicle
what percent of seminal fluid comes from the seminal vesicles?
~70%
what percent of the seminal fluid comes from the prostate gland?
~30%
what is the purpose of the bulbourethral gland?
neutralizes and lubricates the urethra
highly tortuous (twisty) tubes ~15cm long surrounded by fibroelastic CT and smooth muscles
seminal vesicles
which layer of the seminal vesicles is highly amplified?
the mucosa (has a great number of thin complex folds that fill the lumen)
the epithelial cells in the seminal vesicles are rich in:
secretory glands
secretions from the seminal vesicles contain:
coagulating factors and a high content of fructose
what is the purpose of coagulating factors in the semen?
involved in the clotting of semen
what is the purpose of a high fructose content in the semen?
acts as an energy source for sperm to enable movement
the seminal vesicles join the ampulla of the ______ to form ejaculatory ducts in the ______
vas deferens, prostate gland
what is the prostate gland?
a dense walnut-sized gland below the urinary bladder that surrounds the initial portion of the urethra (prostatic urethra)
the smooth muscles in the ______ contract at ejaculation
prostate gland
contains hydrolytic enzymes which liquify the ejaculated clotted semen and release the spermatozoa from their coagulating factors
the prostate gland
the prostate gland empties into the:
urethra
what are the bulbourethral glands?
glands 3-5mm in diameter in the urogenital diaphragm/external urethral sphincter which coats and lubricates the urethra before the passage of sperm
what type of epithelia lines the bulbourethral glands?
cuboidal epithelium
describe the secretions of the bulbourethral glands
secretion is a thick, sticky, alkaline mucus which neutralizes and lubricates the penile urethra
fibrous connective tissue with dense collagen bundles permitting extension of the erectile tissue
tunica albugenia
the erectile tissue of the penis is made of:
large interconnecting vascular spaces lined with endothelial cells, separated by trabeculae (CT and smooth muscles)
vascular spaces decrease in size towards the periphery in the _____ and stays the same size in the ______
corpora cavernosa, corpus spongiosum
what part of the erectile tissue of the penis has more elastic tissue and less smooth muscle?
corpus spongiosum
within the erectile tissue, central arteries supply blood to the:
coropora cavernosa
within the erectile tissue, the _____ receives arterial blood from surrounding connective tissue
corpus spongiosum
parasympathetic stimulation of the erectile tissues causes _____ of the central arteries
vasodilation
how is venous outflow blocked during an erection?
peripheral veins are compressed against the tunica albugenia when the vascular spaces become engorged with blood
what is the effect of sympathetic stimulation on the male reproductive system?
causes ejaculation and constriction of arteries
the spongy urethra transitions between what types of tissues?
urinary (transitional) epithelium –> stratified squamous epithelium (and even keratinized in the glans of the penis)
helps the bulbourethral glands with lubrication of the penile urethra
the urethral glands