BY 32 – SPRING 2002

LECTURE 22:  THE MALE REPRODUCTIVE SYSTEM

Study Outline

 

22.1.  Overview to the Male Reproductive System:

a.       The two functions of the male reproductive system are the production of _____________________________ and _____________________________.

b.      Both functions involve an organ called in general the ___________________ which in the case of the male is called the ____________________________.

c.       In addition to the gonad is a duct system consisting of the _______________; ___________________________; __________________________________; and _______________________________.

d.      There are a number of exocrine glands that contribute to the final composition of a fluid called ________________________________ that also contains the spermatozoa.  These glands include the paired _________________________ and _______________________ glands and the single __________________.

 

22.2.  The Scrotum and Spermatic Cord:

a.       The ________________________________ is a sac of skin that hangs outside of the abdominopelvic cavity and contains the testis and epididymis among other structures.

b.      The blood vessels, nerves, and vas deferens form the _____________________________ which communicates with the pelvic cavity via the __________________________.

c.       The scrotum allows the testes to be maintained a couple of degrees cooler than core body temperature through the presence of the ______________________ and the _____________________________ of the scrotum.  In particular, the pampiniform plexus allows heat conveyed in the arteries to be transferred to ___________________________.  The scrotum can vary its location relative to the body through the action of the ___________________________ and the _______________________ muscles.  The cremaster muscle is derived from the ___________________________.

 

22.3.  The Testis:

a.       Each testis is surrounded by the _____________________________ derived from the peritoneum.  Inside of this layer is the connective tissue capsule called the ____________________________.

b.      The main structural unit of the testis is the __________________________ which is a simple columnar epithelium formed by ____________________ cells.  Within the numerous intercellular compartments between adjacent Sertoli cells are found the various stages of _________________________.

c.       Tight junctions between adjacent Sertoli cell processes form the __________________________ barrier which affords developing spermatocytes protection.  This barrier creates two types of intercellular compartments called ___________________ and ____________________.  While the basal compartments are continuous with interstitial fluids, the ________________________ compartments form a special microenvironment for the developing spermatocytes.

d.      ________________________ cells lie in between seminiferous tubules and are the cells responsible for _________________________ production.

e.       Other ducts of the testis include (in order) the ________________________ and the __________________________.  Connecting these with the epididymis are the __________________________.

 

22.4.  Epididymis, Vas deferens, Ejaculatory Ducts, and Urethra:

a.       The _________________________ consists of a highly coiled duct system that is over 20 feet long, yet lies within the scrotum.  It is subdivided into portions called the _______________________, ______________________, and ________________________________.

b.      The epididymis is lined by a _____________________ epithelium, and represents the storage organ for spermatorzoa in which they finish their __________________________ process.

c.       Leaving the tail of the epididymis is a highly muscular tube called the _______________________ which traverses the inguinal canal to gain access to the ___________________ cavity.  The operation in which this structure is cut to render the male infertile is called a _____________________________.

d.      The point of merger between the vas deferens and duct of the seminal vesicle forms the _____________________ which traverses the _______________ gland to end at the urethra.

e.       The male urethra is subdivided into ______________________________, _______________________, and __________________________ portions.

 

22.5.  Accessory Glands:

a.       The ___________________________ provide about 60% of semen including such components as _______________________________ (energy source for spermatozoa) and prostagalandins which affect the motility of the _______________________________.

b.      The ______________________________ is a single gland that surrounds the urethra as it descends from the bladder. 

c.       The ________________________________ glands are minor glands located below the prostate that produce a mucus-like secretion that neutralizes traces of acidic urine in the urethra.

 

22.6.  The Penis:

a.       Together with the scrotum, the penis constitutes the male ________________ genitalia.

b.      The penis consists of ___________________, _________________________, and ___________________________.  At birth the skin covering the glans forms a cuff called the ____________________________ which is sometimes surgically removed in a procedure called ____________________________.

c.       The penis consists of cylindrical bodies of erectile tissue called the paired __________________________ and single _______________________.

d.      The erectile tissue consists of _________________________ spaces that are normally empty but can fill with blood giving rise to an ______________.

 

22.7.  Spermatogenesis:

a.       In the male the process of spermatogenesis does not begin until the time of __________________________, and then continues essentially undiminished throughout the life of the male.

b.      The entire process takes about ______________________ days to complete, but in a normal male, on the order of _________________________ million spermatozoa are produced each day.

c.       The cycling stem cell for the process is called the _____________________ which divides to form more ____________________________ cells and cells committed to further steps the ______________________________________.  There is also a form of spermatogonium called the ______________________ cell which represents a reserve cell.  All forms of spermatogonia can be found in the ____________________________________ compartments but it is the ____________________________________ cell which migrates to adluminal compartments.

d.      Type B spermatogonia differentiate into _____________________________ which begin meiosis I and complete it to form _________________________.  These cells in turn begin and complete meiosis II to form ________________________________________.

e.       Spermatids differentiate into spermatozoa in a process called ______________________________.  In this process the Golgi apparatus forms the _________________________, and the centrioles develop into a ____________________________.

f.        A mature spermatozoan has three parts called the ______________________, ________________________ and _____________________________.  It is the ____________________ which houses the numerous mitochondria needed to meet the energy demands of this cell.

 

22.8.  Endocrine Regulation:

a.       Normal spermatogenesis depends on the intact structure and function of the _______________________________________ axis.

b.      Certain neurons of the hypothalamus release a hormone called __________________________ which acts on cells of the pituitary gland called ________________________.

c.       In response to GnRH, gonadotropes increase their release of two hormones called _________________________ and __________________________, which in turn are released into blood and circulate to interact with target cells in the ______________________________.

d.      LH interacts with ________________________ cells causing them to increase their production of __________________________.

e.       FSH interacts with ______________________________ cells causing them to increase a number of functions related to spermatogenesis such as increases in the amount of ______________________________________ and increased _____________________________ support to spermatocytes.

f.        Testosterone inhibits the release of __________________________________ from the hypothalamus and ______________________________ release from the pituitary.  It does not directly affect _________________________ release from the pituitary.  Instead, FSH secretion decreases in the presence of _______________________________ released by Sertoli cells.

g.       The main androgen is ___________________________ which together with the other potent androgen _________________________________ interacts with androgen receptors found within the _________________________ of cells.  Androgens act by increasing or decreasing ______________________.

h.       Among the many effects of androgens in the body are the _______________________________; _____________________________; _______________________________; and __________________________.

 

22.9.  The Male Sexual Response:

a.       The male sex response has two phase called _________________________ and ______________________________.

b.      Erection involves stimulation by _____________________________ nerves which cause the release of ___________________________ which is a potent vasodilator leading to filling of the venous spaces.  These nerves also stimulate the secretion of the ____________________________ glands whose secretions aid in lubrication.  Failure to achieve an erection is known as _________________________.

c.       Ejaculation actually consists of two distinct phases called _______________ and ______________________.  Both are under the influence of the ________________________ system.

d.      During emission, the _____________________ contracts first propelling the spermatozoa forward through the ejaculatory ducts into the _____________.  Next the ______________________ contract followed by contraction of the ___________________________.  All these secretions mix in the urethra.

e.       Stretch of the urethra elicits the final phase known as __________________ in which contraction of the _________________________ muscles propel the semen forward out the end of the penis.