Physiology 2130 Lecture Notes - Lecture 68: Vas Deferens, Seminal Vesicle, Epididymis
1 May 2018
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Lecture 068: Male Reproduction
Reproductive System: Function
● Produce hormone
● Produce reproductive cells (gametes)
○ Sperm and oocyte
● Not responsible for homeostasis
○ CAN live without it
Male Anatomy
● Testis
○ Responsible for spermatogenesis and hormones
○ Outside of the body in humans
■ Important because spermatogenesis occurs at a lower temperature (34
℃) than the core body temperature (37 ℃)
○ Ligaments holding the testis
■ Can move up or down to move the testis closer/farther from the body to
adjust the temperature
○ Arteries carry warm blood to the testis meets the cold blood coming from the
veins exiting the testes
■ Counter-current
● Heat moves from the arterial blood to the venous blood
■ There is an exchange of heat that cools the arterial blood so that the
blood entering the testis is lower than the average body temperature
● Epididymis
○ Sperm storage
○ Developed sperm moves into the epididymis for storage and maturation
○ Consists up of a head, middle, and tail
● Vas deferens
○ Transport sperm
○ Tube that takes the sperm from the epididymis to the outside during sexual
arousal
○ Has a muscular wall
■ Able of lots of peristalsis movement to propel sperm to the exit
○ Vasectomy
■ Surgical infertility
■ Cut (irreversible) or plug this tube with gel (reversible)
■ Sperm is continually produced but it can’t be moved outside
● System just reabsorbed the sperm (in the epididymis)
● Seminal vesicles
○ Accessory organ
○ Contrinbutes lots of volume to the ejacuate (60%)
■ Only 10% of the ejaculate is sperm
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● Prostate gland
○ Accessory organ
○ Bladder runs through it to join the urethral
○ Prostate cancer
■ Prostate increase in size
■ Puts pressure on the bladder and bladder drainage
● Pain and urination issues
○ Also contributes fluids to the ejaculate
● Bulbourethral glands
○ Accessory organs
○ Also contribute a small amount of fluids to the ejaculate
● Urethra
○ Common passing for the sperm AND urine
■ Different from females
Accessory Glands
Volume
Composition
Seminal vesicles
60%
● Alkaline
Fructose
● Energy source (ATP)
Semenogelin
● Coagulation protein
● Keeps the sperm together in a
packet to get into the female
reproductive tract
Prostaglandin
● Promotes smooth muscle
contractions as the sperm
enters the female
reproductive tract
Prostate
25%
● Acidic
● Acidity is overridden
by the alkaline of the
seminal vesicles
Citric acid
● For ATP
Prostate specific antigen (PSA)
● Disrupt the clot
○ Cleaves semenogelin
● Allows the sperm to move
freely once it is in the female
reproductive tract
Bulbourethral
5%
● Alkaline
Mucus
● Lubricant
Testes Anatomy
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find more resources at oneclass.com
● Seminiferous tubule
○ Site of spermatogenesis
■ Sperm moves down the lumen, through the network of vessels and into
the head of the epididymis
■ Ciliated vessels
● Wave and move the
concentrated sperm into the
head epididymis
● At this stage the sperm is
immature (can’t fertilize)
○ Makes up of 80% of the bulk of the testis
■ Lots of them, tightly packed
■ All feed into the head of the
epididymis
○ Connective tissue surrounds the
seminiferous tubule
■ Leydig cells are in the
connective tissue
● Cells of the Seminiferous tubule
○ Leydig cells
■ Outside of the tubule
■ Held together by connective
tissue
■ Perfused by blood vessels and
provided with nutrients
○ Sertoli cells
■ Lie inside of seminiferous tubule
■ Produce fluids that help propel the sperm down the tube (fluid pressure)
■ Sperm develop as it travels down the sertoli cells towards the lumen
■ Encapsulated in the basement membrane of the seminiferous tubule
● This membrane separates them from the blood vessels that
provide nutrients
● Relies on diffusion for nutrients
○ Lumen
■ Flows all the way up to the epidermis
■ Receives nutrients from the blood supply
○ Gametes
■ Progressive of development occurs down the sertoli cell towards the
lumen
○ The walls of the seminiferous tubules consist of diploid spermatogonia.
Spermatogenesis
● Spermatogonia (diploid cell)
○ Germ cells
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Important because spermatogenesis occurs at a lower temperature (34. ) than the core body temperature (37 ) Can move up or down to move the testis closer/farther from the body to adjust the temperature. Arteries carry warm blood to the testis meets the cold blood coming from the veins exiting the testes. Heat moves from the arterial blood to the venous blood. There is an exchange of heat that cools the arterial blood so that the blood entering the testis is lower than the average body temperature. Developed sperm moves into the epididymis for storage and maturation. Consists up of a head, middle, and tail. Tube that takes the sperm from the epididymis to the outside during sexual arousal. Able of lots of peristalsis movement to propel sperm to the exit. Cut (irreversible) or plug this tube with gel (reversible) Sperm is continually produced but it can"t be moved outside. System just reabsorbed the sperm (in the epididymis)
