Repro Chp 3: Male Reproductive System

List the 3 purposes of the male reproductive tract

Produce sperm cells able to fertilize the egg

Transmit the male genes to the offspring

Produce hormones such as testosterone

What are the 6 components of the male reproductive tract

spermatic cord

scrotum

testis

excurrent duct system

accessory sex glands

penis and muscles (protrusion, erection, and ejaculation)

The _____ produces spermatozoa and testosterone as well as other substances such as inhibin, estrogen, and a veriety of proteins.

testes

The _____ provides the environment for final maturation of spermatozoa and serves as a storage organ for these cells.

epididymis

The ___ ___ ___ produce seminal plasma and the ___ is the copulatory organ.

accessory sex glands; penis

Pathway of sperm:

The ____ serve as the manufacturing and assembly plant for spermatozoa. A specialized cooling mechanism is required in them to ensure successful _____ (production of sperm). Once produced, sperm pass through ____ _____ in the mediastinum to ___ ____ that lead to the _______. Sperm enter the ____ and ____ of this to undergo changes that allow them to become fertile. After this, sperm enter the ____ which serves as a storage organ prior to ejaculation. Upon sexual excitation, sperm move to the ___ ____ which transports them to the __ _____. While passing to the penis, sperm are mixed with fluids produced by the ___ __ ____ to become ___ ____ meaning they are ready to enter the female reproductive tract. The 'delivery system' is the _______.

testes; spermatogenesis; rete tubules; efferent ducts; epididymis; head (caput) and body (corpus); tail (cauda); vas deferens; pelvic urethra; accessory sex glands; seminal plasma; penis

The _____ is a two-lobed sac that protects and supports the testes and is required for proper ____ _____ as the testes need to be a couple degrees cooler than body temperature for proper sperm production.

scrotum; temperature regulation

List the 4 major layers of the scrotum from outermost to innermost

1. Skin

2. Tunica Dartos

3. Scrotal fascia

4. Parietal vaginal tunic

The scrotal skin is heavily populated with ___ ___ that are required for maintenance of proper testicular temperature. These are regulated by ___ ____ that occur in the hypothalamus.

sweat glands; thermosensitive neurons/nerves

When the male experiences elevated body temperature or scrotal temperatures, the ______ detects this change and sends nerve impulses to the ____ _____. Sweating allows the scrotum (and thus testes) to be cooled by ____ ____ ____.

hypothalamus; sweat glands; evaporative heat transfer

The scrotal skin also has a large number of ____ ____ which are sensory nerves that govern both the degree of ___ ____ and _____.

thermosensitive nerves; scrotal sweating and respiration

When the scrotal temperature reaches about 39°C, ____ _____ in the scrotal skin send impulses to the _____ center in the brain that then activates ______ ____ to begin ____ to release heat.

thermosensitive nerves; respiratory; respiratory muscles; polypnea (panting)

It is important the scrotal skin is able to regulate scrotal temperature (sweat and respiration) because heat reduces _____ before spermatogenesis occurs which furthermore reduces _____ _____.

motility; survival of the embryo

When ____ _____ occurs in the scrotal skin (often when finishing animals or after castration), it decreases the cooling efficiency of the scrotum thus reducing spermatogenic efficiency, viability, and fertility.

fat accumulation

The tunica dartos is the ____ _____ layer that lies just beneath the scrotal skin that is important in ____ _____. It maintains contractions to ____ the testes during cooler temperatures or ____ the testes during hotter temperatures.

smooth muscle; temperature regulation; lift; lower

Development and maintenance of the contractility of the tunica dartos are under _____ _____. For example, the ability of the tunica dartos to contract in response to cold temperatures in lost in castrated males because this hormone is absent.

testosterone control

____ ____ bulls are male cattle that have been made infertile using a specific management technique that pushes their testicles tight against the body wall OR have small scrotal surface area. Spermatogenesis meaning ______ and sperm are still produced but sperm cells are not viable due to elevated temperatures`.

Short Scrotum; testosterone

T/F The scrotal fascia and parietal vaginal tunic are the inner layers of the scrotum that function in protect and support.

true

The primary and secondary organs of the male reproductive tract work in concert for the ____, ____, and ____ of spermatozoa to be deposited in the female reproductive tract.

formation, maturation, and transport

The ____ are the primary organ of the male reproductive system because they produce both...

testes; sperm and testosterone

What are the 3 secondary organs in the male reproductive system?

epididymis, vas deferens, penis

What are the 3 accesory organs in the male reproductive system?

seminal vesicles, prostate, bulbourethral gland (Cowper's gland)

T/F It is often mistaken that the penis is the primary organ of the male reproductive tract however, it simply serves as the delivery organ of spermatozoa and seminal fluid.

true

The ___ ____ extends from the inguinal ring (passageway from the body cavity into scrotum) to its attachment on the dorsal pole of the testis. It provides a pathway to and from the body for the ...(3)

spermatic cord; testicular vasculature, lymphatics, and nerves

The spermatic cord ____ ___ in the scrotum and houses the ductus deferens, ___ ____, and a specialized vascular network called the __ ____.

suspends the testes; cremaster muscle; pampiniform plexus

T/F Both the tunica dartos and spermatic cord suspend the testes in the scrotum however they serve their function differently as the tunica dartos is focused on temperature regulation.

true

T/F There are two spermatic cords in the male: one for each teste.

true

The pampiniform plexus is found in the spermatic cord and is the vascular structure consisting of an intertwined _____ _____ and ______. This structure functions as a ___ __ ____ that keeps the testes ___ cooler than the body for spermatogenesis to occur.

testicular artery and vein; countercurrent heat exchanger; 4-6°C

The spermatic/testicular artery in the pampiniform plexus is ___ ____ and branches from the abdominal aorta. The testicular veins in the spermatic cord branch into an elaborate ____ that "wraps" around the artery therefore creating the countercurrent heat exchange.

highly coiled/convoluted; network

Arterial blood enters the pampiniform plexus at _____and is cooled to ___ at the testicles. This occurs through counter current heat exchange, where heat from the ____ ____blood from the body is transferred to the ____ _______ blood leaving the surface of the testes. As warm blood travels down, it is surrounded by cooler venous blood, allowing heat to transfer from the ___ ____ entering the testicles to the ___ ____ exiting the testicles.

39°C; 34°C; warm arterial; cooler venous; arterial blood; venous blood

The close relationship between the venous and arterial blood supply in the paniform plexus also results in the exchange of ______.

testosterone

Arterial blood enters the pampiniform plexus with a ____ concentration of testosterone while testosterone is at ____ concentrations in the venous drainage from the testicles. Therefore as blood passes through the panpiniform plexus, testosterone moves from the ____ to the _____ and equilibriates the concentration before moving into the body.

low; high; vein; artery

The primary muscle supporting the testes and coursing the length of the spermatic cord is the __ ____. Its main functions are ____ the testes, controlling ___ ___, and ____ ___ through the testes by short rhythmic contractions.

cremaster muscle; supporting; testicular temperature; pumping blood

The cremaster muscle is a ____ ____ that aids in control of testicular temperature by ___ and ____ the testes. It specifically raises the testes during ___ temperature and during ___ or ____ response.

s.

striated muscle; raising; lowering; cold; flight or fright

T/F The cremaster muscle raises the testes during an animals fight or flight response in order to protect the testes during a fight and to move them out of the way. This occurs no matter what the temperature as the animal is focused on survival, not reproduction at the time.

true

Can striated or smooth muscles maintain sustained contractions?

smooth muscle

The cremaster muscle is a ____ muscle unlike the tunica dartos which is a ____ muscle. Both regulate the temperature in the testes, however the cremaster muscle ______ sustain contractions and the tunica dartos ___ sustain contractions. Therefore, the ___ _____ raises or lowers the testes which the ____ _____ then sustains.

striated; smooth; cannot; can; cremaster muscle; tunica dartos

Birds, marine mammals, armadillos, and reptiles have testes located _____ the body in a retroperitoneal position thus the mechanisms associated with ___ ____ are not as important for them.

inside; temperature regulation

The ____ are paired organs that descend outside the body within the scrotum. They are the ___ production and output organs that control and house ______.

testes; sperm; spermatogenesis

The testes...

- produce the male hormone, ______

- produce ___(3)_____ that improve sperm function

- produce ____ which sperm are suspended in and facilitates their removal from the testes

testosterone; inhibin, estrogens, proteins; fluid

The ____ provides physical protection for the testes.

scrotum

It is very important that the testes are ___ ____ as location is essential for normal sperm formation. The testes need to be ____ cooler than the body temperature in order for viable sperm to be produced.

temperature regulated; 4-5 degrees

What are the 3 structures that coordinate temperature regulation of the testicles?

tunica dartos, cremaster muscle, pampiniform plexuses

The ____ is the temperature-sensitive layer of muscle located in the walls of the scrotum that ____ when the testes are hot and _____ when cold as it is able to ____ contractions.

tunica dartos; relaxes; contractions; sustain

The ____ ___ controls the _____ of the testicle to the body. The lengthening or shortening depends on the ____ ____.

cremaster muscle; proximity; environmental temperature

The ___ ____ is a coil of testicular veins which cool arterial blood entering the testicles and transfer it heat to the ___ ___ leaving the testicles. It creates a counter-current heat exchange by this blood flow process.

pampiniform plexus; venous blood

The testes are composed of 3 areas. List them from outermost to innermost

Testicular capsule

Parenchyma (seminiferous tubules)

Mediastinum (rete tubules)

The covering of the testicles, or the testicular capsule, is composed of two layers. The ____ ____ is the dense white connective tissue that directly covers the testes and the ___ ___ ____ is peritoneum that adheres to the testes and is closely associated with the first layer.

tunica albuginea; visceral vaginal tunic

The ____ _____ sends many finger-like projections into the parenchyma of the testicle where these septal projections join with the _____. The interior surfaces of the tunica albuginea and the surfaces of the septal divisions form the ____ of the testes which house the seminiferous tubules. The surfaces of the lobules are called _____.

tunica albuginea; mediastinum; lobules; tenica vasculosa

T/F Though the testicular capsule was once considered to be an inert covering of the testes whose sole function was to form the outer boundary of the testes, it is now apparent that the testicular capsule is a dynamic "suborgan" capable of undergoing changes in direction response to hormones and neurotransmitters.

true

In the testicular capsule, the tunica albuginea is not only composed of connective tissue but also contains ___ ____. Acetylcholine and norepinephrine can cause ___ ____ of this muscle which facilitate the movement of ____ and ____ transport into the ____ ____ (tubules which the testicular capsule houses).

smooth muscle; rhythmic contraction; sperm; fluid; rete tubules

The ____ is the major cellular mass of the testes which has a ___, ____ appearance. It is made up of ____ ____ (site of spermatogenesis) and ___ ____ (blood vessels, nerves, lymphatics, connective tissue, leydig cells).

parenchyma; soft, tan; seminiferous tubules; interstitial tissue

The _______ tubules in the parenchyma of the testes form highly convoluted loops which join with the ___ tubules in the mediastinum. Each seminiferous tubule has a convoluted portion called the ___ ____ and a straight portion called the ____. Spermatogenesis takes place in the __ _____.

seminiferous tubules; rete tubules; tubulus contortus; rectus; tubulus contortus

The parenchyma can be broken up into two compartments. The ___ ____ consists of the seminiferous tubules and the cells/materials inside them. Specifically, the ___ ____ are found in the seminiferous tubules. The ____ ____ consists of the blood vessels, connective tissue, lymphatics, and nerves outside of the seminiferous tubules. Specifically, the __ ____ which produce testosterone and other hormones.

tubular compartment; sertoli cells; interstitial compartment; leydig cells

The tubular compartment of the seminiferous tubules has a basement membrane and lumen that house what 3 things?

sertoli cells, developing germ cells, peritubular cells

The seminiferous tubule (in the tubular compartment) is composed of an outer ___ ____ and a layer of ___ ____ which consists of developing germ cells and Sertoli cells. The inside of the seminiferous tubule is called the ____.

basement membrane; seminiferous epithelium; lumen

Both sertoli cells and peritubular cells are needed for spermatogenesis as sertoli cells govern _____ and peritubular cells secrete ____ for ____ ____.

spermatogenesis; protein; hormone control

____ ____ "host" developing germ cells that become spermatozoa and are found in the seminiferous tubules. They contains receptors for both the protein hormone ____ and the steroid hormone _____.

Sertoli cells; FSH; testosterone

T/F Since each sertoli cell hosts a maximum number of developing sperm cells for spermatogenesis, more sertoli cells = more sperm cells.

true

List the 4 hormones Sertoli cells produce

androgen binding hormone, sulfated glycoprotein (SGP) 1 and 2, transferrin, inhibin

Androgen binding hormone is a ______ transport protein. Sulfated glycoprotein (SGP) 1 and 2 are related to ____ ___ and providing a detergent effect that allows ____ ____ through the tubular network of the testes.

testosterone; fertility acquisition; fluid movement

Transferrin is an ___ transport protein required for spermatogenesis and Inhibin is a suppressor of ____.

iron; FSH

The seminiferous tubule is surrounded by contractile ____ ___ that contract to assists in the movement of spermatozoa into the rete tubules.

peritubular cells

The ___ ____ ____ is a group of specialized junctions between Sertoli cells that connect and anchor the cells together and help regulate the movement of developing sperm cells between them.

Sertoli cell junctional complex

The peritubular cells surrounding the seminiferous tubules and the Sertoli cell junctional complexed form the ____ _____. The primary purpose of this is to prevent ____ ____ from destroying developing germ cells as they are haploid cells and considered 'foreign' to the body.

blood-testis barrier; autoimmune reactions

The blood-testis barrier prevents ___ ___ of developing germ cells (undergoing meiosis, so would cause an immune response). It does this by "screening" materials in the interstitial compartment of the seminiferous tubules before allowing the materials to enter the tubular compartment with developing germ cells. Most importantly, it excludes ___ ___ (macrophages, lymphocytes) and _____ (antibodies) from entering.

immunologic destruction; immune cells; immunoglobulins

The ____ is the inner layer of the testes which houses the ducts called the ___ tubules. It is a central core of the testes that has a white appearance as it is made of ___ ____ which helps to prevent ____ of the testes and rete tubules so spermatozoa and fluid can move free out of the testis.

mediastinum; rete; connective tissue; collapse

T/F The seminiferous tubules of the parenchyma are connected to the rete tubules of the mediastinum.

true

The excurrent duct system is responsible for transporting sperm out of the mediastinum and to the penis. What are the 3 parts of this system?

efferent ducts, epididymal ducts, ductus deferens

The efferent ducts are responsible for moving new ___ and ____ ____ from the rete tubules into the _____ ____.

spermatozoa and tubular fluid; epididymal duct

T/F The head of the epididymis contains the point of connection between the efferent ducts and the initial segment of the epididymal duct.

true

The epididymal duct varies in ____ depending on the species and is surrounded by smooth muscle that provides ___ ____ to move spermatozoa from the ____ to the _____ of the epididymis.

length; rhythmic contractions; head (caput) to tail (cauda)

T/F It takes longer/shorter amount of time to pass through the epididymis ("finishing shop") depending on the species. This is known as the epididymal transit time.

true

The ___ _____ is the final segment of the excurrent duct system that transport mature sperm from the epididymis to the ejaculatory duct.

ductus deferens

The ____ ____ are tiny channels which transport spermatozoa out of the testis. Sperm travel from the rete tubules to the ___ ____ which converge to a single duct called the ______.

rete tubules; efferent ducts; epididymis

As sperm enter the efferent ducts and epididymal duct, their concentration is low because they are diluted in ____ ____ which comes from the rete tubules in the mediastinum.

rete fluid

Many rete tubules and efferent ducts unite to form a single tubule for the epididymis that is around _____ long.

130' to 160' (feet)

List the 4 functions of the epididymis

1. Transport of developing sperm cells from testicles to the vas deferens

2. Concentration of the sperm absorption of surplus fluids

3. Maturation of developing spermatozoa

4. Storage of viable sperm cells in the epididymis tail

T/F The epididymis functions in increasing the concentration of sperm by absorbing the excess tubule fluid that is produced during spermatogenesis.

true

The epididymis is organized into 3 distinct regions known as the...

Head (caput)

Body (corpus)

Tail (cauda)

In the caput and corpus of the epididymis sperm undergo _____ that takes approximately ___ ____. In the cauda, sperm are mainly _____ and waiting for the "big deed."

maturation; 2 weeks; storage

Sperm are viable when they reach the ____, however, they are not activated to fertilize because they have to undergo _____ which is the final maturation process that sperm must undergo inside the female reproductive tract to gain the ability to fertilize an egg.

cauda; capacitation

Spermatozoa entering the head of the epididymis possess a cytoplasmic droplet located near the base of the head of the sperm. This droplet is referred to as the ___ ___ _____. As spermatozoa move through the epididymis, the droplet moves down with their trails and is called the ___ ___ ____. Spermatozoa in the tail of the epididymis possess a __ __ ____.

proximal cytoplasmic droplet; translocating cytoplasmic droplet; distal cytoplasmic droplet

The time required to transport sperm from the proximal head of the epididymis to the distal tail is referred to as the ___ __ ____. It ranges from ___ ___ in the stallion to ___ ____ in the bull.

epididymal transit time; 9 days; 14 days

The epididymal transit time through the head and body of the epididymis is ____, but ___ ___ increases the travel time through the tail.

constant; sexual excitement

T/F Epididymal transit time through the head and body is not altered by sexual excitement.

true

Sperm move from the epididymis to the ductus deferens by _____ that occur during sexual excitement.

contractions

During _____, spermatozoa stored in the cauda travel via the ductus deferens to the ___ _____. When reaching this part of the tract, sperm mix with __ ___ from accessory sex glands.

excitation; pelvic urethra; seminal fluid

T/F A high ejaculation frequency = higher sperm in ejaculate.

false; lower sperm

Sperm spending an unusually long time in the tail (such as after long periods of sexual rest) start to have a ___ _____ when compared to sperm from animals ejaculated routinely.

decreased quality

The number of sperm in the distal tail of the epididymis can be altered dramatically by the _____ of _____. It is important to recognize that the epididymis not only controls the maturation and fertility acquisition of sperm but also their ____ from the male reproductive system. With sperm production rates of several billion per day, the epididymis provides a way to continually move sperm out of the tract by ____ _____ of the epididymis and ductus deferens resulting in the gradual trickle of sperm out of the tail, through the ductus deferens, into the pelvic urethra where they are flushed out of the tract during ________.

frequency of ejaculation; exit; periodic contractions; urination

Path of Testes:

1. ________: high speed manufacturing where sperm are made in a cool environment

2. ______: finishing shop where fluid is absorbed and sperm mature through membrane changes, nuclear & flagellar stabilization, motility, cytoplasmic droplet translocation

3. _____: warehouse and shipping where sperm is stored with quantity for 5 to 10 ejaculations which occur from smooth muscle contractions after sexual stimulation

4. _____: final alterations and packaging where metabolic substrates and surface coatings are added to help transport sperm

5. ______: delivery system involved in erection, protrusion, emission, and ejacultion

1. testes

2. head and body of epididymis (caput and corpus)

3. tail of epididymis (cauda)

4. accessory sex glands

5. penis

Fluid that is produced from the epididymis tail and accessory sex glands is called ___ ____. When this is added to sperm it is referred to as _____.

seminal plasma; semen

What is the fluid called that is ejaculated into the female reproductive tract?

semen

List the 4 accessory sex glands (these are species dependent as some species have different accessory sex glands)

ampulla, vesicular glands, prostate, bulbourethral gland

The accessory sex glands and epidiymis are responsible for the secretion of ____ ____. This is the liquid, __ ____ portion of semen that provides _____ to sperm by providing a fluid vehicle for ______ of the sperm especially during natural service.

seminal plasma; non-cellular; mobility; delivery

Seminal plasma _____ to the fertility of sperm by providing mobility but is not ____ for fertility.

adds; required

T/F Seminal plasma is not required for fertility as it is not required for the sperm and egg to meet and become a zygote. It simply allows a medium for sperm to travel in to better increase the chances that fertility occurs.

true

Seminal plasma is secreted into the _____ of the pelvic urethra. In the ____(2)____ seminal plasma has coagulative properties that ____ the female reproductive tract and minimize the loss of semen through backflow following copulation and ejaculation.

lumen; boar and stallion; plug

The _____ is the accessory sex gland that is an enlargement of the ductus deferens which opens directly into the pelvic urethra. It is not as prominent in the ____.

ampulla; boar