Information

14.2: Anatomy and Physiology of the Male Reproductive System - Biology

14.2: Anatomy and Physiology of the Male Reproductive System - Biology


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Unique for its role in human reproduction, a gamete is a specialized sex cell carrying 23 chromosomes—one half the number in body cells. In this section, we examine each of these different structures, and discuss the process of sperm production and transport.

Male Reproductive System

The structures of the male reproductive system include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.


Scrotum

The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis. This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.

The dartos muscle makes up the subcutaneous muscle layer of the scrotum. It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.

The Scrotum and Testes

This anterior view shows the structures of the scrotum and testes.


Testes

The testes (singular = testis) are the male gonads—that is, the male reproductive organs. They produce both sperm and androgens, such as testosterone, and are active throughout the reproductive lifespan of the male.

Paired ovals, the testes are each approximately 4 to 5 cm in length and are housed within the scrotum. They are surrounded by two distinct layers of protective connective tissue. The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer. Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a male fetus, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.

Anatomy of the Testis

This sagittal view shows the seminiferous tubules, the site of sperm production. Formed sperm are transferred to the epididymis, where they mature. They leave the epididymis during an ejaculation via the ductus deferens.


The tightly coiled seminiferous tubules form the bulk of each testis. They are composed of developing sperm cells surrounding a lumen, the hollow center of the tubule, where formed sperm are released into the duct system of the testis. Specifically, from the lumens of the seminiferous tubules, sperm move into the straight tubules (or tubuli recti), and from there into a fine meshwork of tubules called the rete testes. Sperm leave the rete testes, and the testis itself, through the 15 to 20 efferent ductules that cross the tunica albuginea.

Inside the seminiferous tubules are six different cell types. These include supporting cells called sustentacular cells, as well as five types of developing sperm cells called germ cells. Germ cell development progresses from the basement membrane—at the perimeter of the tubule—toward the lumen. Let’s look more closely at these cell types.

Sertoli Cells

Surrounding all stages of the developing sperm cells are elongate, branching Sertoli cells. Sertoli cells are a type of supporting cell called a sustentacular cell, or sustenocyte, that are typically found in epithelial tissue. Sertoli cells secrete signaling molecules that promote sperm production and can control whether germ cells live or die. They extend physically around the germ cells from the peripheral basement membrane of the seminiferous tubules to the lumen. Tight junctions between these sustentacular cells create the blood–testis barrier, which keeps bloodborne substances from reaching the germ cells and, at the same time, keeps surface antigens on developing germ cells from escaping into the bloodstream and prompting an autoimmune response.

Germ Cells

The least mature cells, the spermatogonia (singular = spermatogonium), line the basement membrane inside the tubule. Spermatogonia are the stem cells of the testis, which means that they are still able to differentiate into a variety of different cell types throughout adulthood. Spermatogonia divide to produce primary and secondary spermatocytes, then spermatids, which finally produce formed sperm. The process that begins with spermatogonia and concludes with the production of sperm is called spermatogenesis.

Spermatogenesis

As just noted, spermatogenesis occurs in the seminiferous tubules that form the bulk of each testis. The process begins at puberty, after which time sperm are produced constantly throughout a man’s life. One production cycle, from spermatogonia through formed sperm, takes approximately 64 days. A new cycle starts approximately every 16 days, although this timing is not synchronous across the seminiferous tubules. Sperm counts—the total number of sperm a man produces—slowly decline after age 35, and some studies suggest that smoking can lower sperm counts irrespective of age.

The process of spermatogenesis begins with mitosis of the diploid spermatogonia. Because these cells are diploid (2n), they each have a complete copy of the father’s genetic material, or 46 chromosomes. However, mature gametes are haploid (1n), containing 23 chromosomes—meaning that daughter cells of spermatogonia must undergo a second cellular division through the process of meiosis.

Spermatogenesis

(a) Mitosis of a spermatogonial stem cell involves a single cell division that results in two identical, diploid daughter cells (spermatogonia to primary spermatocyte). Meiosis has two rounds of cell division: primary spermatocyte to secondary spermatocyte, and then secondary spermatocyte to spermatid. This produces four haploid daughter cells (spermatids). (b) In this electron micrograph of a cross-section of a seminiferous tubule from a rat, the lumen is the light-shaded area in the center of the image. The location of the primary spermatocytes is near the basement membrane, and the early spermatids are approaching the lumen (tissue source: rat). EM × 900. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)


Two identical diploid cells result from spermatogonia mitosis. One of these cells remains a spermatogonium, and the other becomes a primary spermatocyte, the next stage in the process of spermatogenesis. As in mitosis, DNA is replicated in a primary spermatocyte, and the cell undergoes cell division to produce two cells with identical chromosomes. Each of these is a secondary spermatocyte. Now a second round of cell division occurs in both of the secondary spermatocytes, separating the chromosome pairs. This second meiotic division results in a total of four cells with only half of the number of chromosomes. Each of these new cells is a spermatid. Although haploid, early spermatids look very similar to cells in the earlier stages of spermatogenesis, with a round shape, central nucleus, and large amount of cytoplasm. A process called spermiogenesis transforms these early spermatids, reducing the cytoplasm, and beginning the formation of the parts of a true sperm. The fifth stage of germ cell formation—spermatozoa, or formed sperm—is the end result of this process, which occurs in the portion of the tubule nearest the lumen. Eventually, the sperm are released into the lumen and are moved along a series of ducts in the testis toward a structure called the epididymis for the next step of sperm maturation.

Structure of Formed Sperm

Sperm are smaller than most cells in the body; in fact, the volume of a sperm cell is 85,000 times less than that of the female gamete. Approximately 100 to 300 million sperm are produced each day, whereas women typically ovulate only one oocyte per month as is true for most cells in the body, the structure of sperm cells speaks to their function. Sperm have a distinctive head, mid-piece, and tail region. The head of the sperm contains the extremely compact haploid nucleus with very little cytoplasm. These qualities contribute to the overall small size of the sperm (the head is only 5 μm long). A structure called the acrosome covers most of the head of the sperm cell as a “cap” that is filled with lysosomal enzymes important for preparing sperm to participate in fertilization. Tightly packed mitochondria fill the mid-piece of the sperm. ATP produced by these mitochondria will power the flagellum, which extends from the neck and the mid-piece through the tail of the sperm, enabling it to move the entire sperm cell. The central strand of the flagellum, the axial filament, is formed from one centriole inside the maturing sperm cell during the final stages of spermatogenesis.

Structure of Sperm

Sperm cells are divided into a head, containing DNA; a mid-piece, containing mitochondria; and a tail, providing motility. The acrosome is oval and somewhat flattened.


Sperm Transport

To fertilize an egg, sperm must be moved from the seminiferous tubules in the testes, through the epididymis, and—later during ejaculation—along the length of the penis and out into the female reproductive tract.

Role of the Epididymis

From the lumen of the seminiferous tubules, the immotile sperm are surrounded by testicular fluid and moved to the epididymis (plural = epididymides), a coiled tube attached to the testis where newly formed sperm continue to mature. Though the epididymis does not take up much room in its tightly coiled state, it would be approximately 6 m (20 feet) long if straightened. It takes an average of 12 days for sperm to move through the coils of the epididymis, with the shortest recorded transit time in humans being one day. Sperm enter the head of the epididymis and are moved along predominantly by the contraction of smooth muscles lining the epididymal tubes. As they are moved along the length of the epididymis, the sperm further mature and acquire the ability to move under their own power. Once inside the female reproductive tract, they will use this ability to move independently toward the unfertilized egg. The more mature sperm are then stored in the tail of the epididymis (the final section) until ejaculation occurs.

Duct System

During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord. Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt sperm delivery can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of male birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent, and advise men to undergo it only if they are certain they no longer wish to father children.

From each epididymis, each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues posteriorly to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).

Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that the male ejaculates. The bulk of semen is produced by three critical accessory glands of the male reproductive system: the seminal vesicles, the prostate, and the bulbourethral glands.

Seminal Vesicles

As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle. The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement through the female reproductive tract.

The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.

Prostate Gland

As shown in the image below, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid—now called semen—that is critical to first coagulate and then decoagulate the semen following ejaculation. The temporary thickening of semen helps retain it within the female reproductive tract, providing time for sperm to utilize the fructose provided by seminal vesicle secretions. When the semen regains its fluid state, sperm can then pass farther into the female reproductive tract.

Male Reproductive System

The prostate normally doubles in size during puberty. At approximately age 25, it gradually begins to enlarge again. This enlargement does not usually cause problems; however, abnormal growth of the prostate, or benign prostatic hyperplasia (BPH), can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, such as a frequent and intense urge to urinate, a weak stream, and a sensation that the bladder has not emptied completely. By age 60, approximately 40 percent of men have some degree of BPH. By age 80, the number of affected individuals has jumped to as many as 80 percent. Treatments for BPH attempt to relieve the pressure on the urethra so that urine can flow more normally. Mild to moderate symptoms are treated with medication, whereas severe enlargement of the prostate is treated by surgery in which a portion of the prostate tissue is removed.

Bulbourethral Glands

The final addition to semen is made by two bulbourethral glands (or Cowper’s glands) that release a thick, salty fluid that lubricates the end of the urethra and the vagina, and helps to clean urine residues from the penile urethra. The fluid from these accessory glands is released after the male becomes sexually aroused, and shortly before the release of the semen. It is therefore sometimes called pre-ejaculate. It is important to note that, in addition to the lubricating proteins, it is possible for bulbourethral fluid to pick up sperm already present in the urethra, and therefore it may be able to cause pregnancy.

The Penis

The penis is the male organ of copulation (sexual intercourse). It is flaccid for non-sexual actions, such as urination, and turgid and rod-like with sexual arousal. When erect, the stiffness of the organ allows it to penetrate into the vagina and deposit semen into the female reproductive tract.

Cross-Sectional Anatomy of the Penis

Three columns of erectile tissue make up most of the volume of the penis.


The shaft of the penis surrounds the urethra. The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, which can be felt as a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, resulting in very sensitive skin that influences the likelihood of ejaculation. The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricate and protect the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth.

Both sexual arousal and REM sleep (during which dreaming occurs) can induce an erection. Penile erections are the result of vasocongestion, or engorgement of the tissues because of more arterial blood flowing into the penis than is leaving in the veins. During sexual arousal, nitric oxide (NO) is released from nerve endings near blood vessels within the corpora cavernosa and spongiosum. Release of NO activates a signaling pathway that results in relaxation of the smooth muscles that surround the penile arteries, causing them to dilate. This dilation increases the amount of blood that can enter the penis and induces the endothelial cells in the penile arterial walls to also secrete NO and perpetuate the vasodilation. The rapid increase in blood volume fills the erectile chambers, and the increased pressure of the filled chambers compresses the thin-walled penile venules, preventing venous drainage of the penis. The result of this increased blood flow to the penis and reduced blood return from the penis is erection. Depending on the flaccid dimensions of a penis, it can increase in size slightly or greatly during erection, with the average length of an erect penis measuring approximately 15 cm.

Testosterone

Testosterone, an androgen, is a steroid hormone produced by Leydig cells. The alternate term for Leydig cells, interstitial cells, reflects their location between the seminiferous tubules in the testes. In male embryos, testosterone is secreted by Leydig cells by the seventh week of development, with peak concentrations reached in the second trimester. This early release of testosterone results in the anatomical differentiation of the male sexual organs. In childhood, testosterone concentrations are low. They increase during puberty, activating characteristic physical changes and initiating spermatogenesis.

Functions of Testosterone

The continued presence of testosterone is necessary to keep the male reproductive system working properly, and Leydig cells produce approximately 6 to 7 mg of testosterone per day. Testicular steroidogenesis (the manufacture of androgens, including testosterone) results in testosterone concentrations that are 100 times higher in the testes than in the circulation. Maintaining these normal concentrations of testosterone promotes spermatogenesis, whereas low levels of testosterone can lead to infertility. In addition to intratesticular secretion, testosterone is also released into the systemic circulation and plays an important role in muscle development, bone growth, the development of secondary sex characteristics, and maintaining libido (sex drive) in both males and females. In females, the ovaries secrete small amounts of testosterone, although most is converted to estradiol. A small amount of testosterone is also secreted by the adrenal glands in both sexes.

Control of Testosterone

The regulation of testosterone concentrations throughout the body is critical for male reproductive function. The intricate interplay between the endocrine system and the reproductive system is shown in the image below.

Regulation of Testosterone Production

The hypothalamus and pituitary gland regulate the production of testosterone and the cells that assist in spermatogenesis. GnRH activates the anterior pituitary to produce LH and FSH, which in turn stimulate Leydig cells and Sertoli cells, respectively. The system is a negative feedback loop because the end products of the pathway, testosterone and inhibin, interact with the activity of GnRH to inhibit their own production.


The regulation of Leydig cell production of testosterone begins outside of the testes. The hypothalamus and the pituitary gland in the brain integrate external and internal signals to control testosterone synthesis and secretion. The regulation begins in the hypothalamus. Pulsatile release of a hormone called gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the endocrine release of hormones from the pituitary gland. Binding of GnRH to its receptors on the anterior pituitary gland stimulates release of the two gonadotropins: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These two hormones are critical for reproductive function in both men and women. In men, FSH binds predominantly to the Sertoli cells within the seminiferous tubules to promote spermatogenesis. FSH also stimulates the Sertoli cells to produce hormones called inhibins, which function to inhibit FSH release from the pituitary, thus reducing testosterone secretion. These polypeptide hormones correlate directly with Sertoli cell function and sperm number; inhibin B can be used as a marker of spermatogenic activity. In men, LH binds to receptors on Leydig cells in the testes and upregulates the production of testosterone.

A negative feedback loop predominantly controls the synthesis and secretion of both FSH and LH. Low blood concentrations of testosterone stimulate the hypothalamic release of GnRH. GnRH then stimulates the anterior pituitary to secrete LH into the bloodstream. In the testis, LH binds to LH receptors on Leydig cells and stimulates the release of testosterone. When concentrations of testosterone in the blood reach a critical threshold, testosterone itself will bind to androgen receptors on both the hypothalamus and the anterior pituitary, inhibiting the synthesis and secretion of GnRH and LH, respectively. When the blood concentrations of testosterone once again decline, testosterone no longer interacts with the receptors to the same degree and GnRH and LH are once again secreted, stimulating more testosterone production. This same process occurs with FSH and inhibin to control spermatogenesis.

Aging and the Male Reproductive System

Declines in Leydig cell activity can occur in men beginning at 40 to 50 years of age. The resulting reduction in circulating testosterone concentrations can lead to symptoms of andropause, also known as male menopause. While the reduction in sex steroids in men is akin to female menopause, there is no clear sign—such as a lack of a menstrual period—to denote the initiation of andropause. Instead, men report feelings of fatigue, reduced muscle mass, depression, anxiety, irritability, loss of libido, and insomnia. A reduction in spermatogenesis resulting in lowered fertility is also reported, and sexual dysfunction can also be associated with andropausal symptoms.

Whereas some researchers believe that certain aspects of andropause are difficult to tease apart from aging in general, testosterone replacement is sometimes prescribed to alleviate some symptoms. Recent studies have shown a benefit from androgen replacement therapy on the new onset of depression in elderly men; however, other studies caution against testosterone replacement for long-term treatment of andropause symptoms, showing that high doses can sharply increase the risk of both heart disease and prostate cancer.


14.2: Anatomy and Physiology of the Male Reproductive System - Biology

By the end of this section, you will be able to:

  • Describe the structure and function of the organs of the female reproductive system
  • List the steps of oogenesis
  • Describe the hormonal changes that occur during the ovarian and menstrual cycles
  • Trace the path of an oocyte from ovary to fertilization

The female reproductive system functions to produce gametes and reproductive hormones, just like the male reproductive system however, it also has the additional task of supporting the developing fetus and delivering it to the outside world. Unlike its male counterpart, the female reproductive system is located primarily inside the pelvic cavity. Recall that the ovaries are the female gonads. The gamete they produce is called an oocyte. We’ll discuss the production of oocytes in detail shortly. First, let’s look at some of the structures of the female reproductive system.

Figure 1. The major organs of the female reproductive system are located inside the pelvic cavity.


Week 12- male reproductive

Learning objectives 14.1 Name the organs of the male reproductive system and state the general function of each 14.2 Identify the composition of semen and name the glands that produce it 14.3 Outline the hormonal control of testicular function

Anatomy of male reproductive system  Testes o 4 cm x 2.5cm o Capsule surrounds each testicle o Internally divided into lobes containing seminiferous tubules o Produces sperm  Seminiferous tubules o Located inside each lobe in testes o Tightly coiled structures o Function as sperm forming factories o Empty sperm into the rete testis o Sperm travels through the rete testis to the epididymis o Surrounded by interstitial cells which produce the androgen testosterone  Duct system o Epididymis  First part of duct system  Temporary storage site for immature sperm cells (at least 20 days) until they mature and gain the ability to swim  Fluid here contains antimicrobial proteins  Expels sperm into the vas deferens with the contraction of muscles in the epididymis walls o Ductus deferens (vas deferens)  Carries sperm from the epididymis to ejaculatory duct  Runs upwards to pass through the inguinal canal and over the bladder  Moves sperm by peristalsis  Ductus deferens, blood and nerves are wrapped together in a connective tissue sheath called the spermatic cord o Urethra  Serves both urinary and reproductive systems  Urine and sperm never pass at the same time  Internal sphincter constricts which prevents urine entering the urethra but also stops sperm entering the bladder  Accessory glands o Seminal vesicle  Located at base of bladder  Produce 60% of semen volume  Thick yellow secretion – rich in fructose, vitamin C and prostaglandins

 Nourishes and energises sperm o Prostate gland  Encircles upper part of urethra below bladder, anterior to rectum  Secretes 30% of semen volume  Secretes milky fluid that activates the sperm o Bulbourethral gland  Tiny gland inferior to prostate  Produce thick clear mucus that drains into urethra prior to ejaculation  Cleanses urethra  External genitals o Penis o Scrotum  Divided sac of skin outside the abdomen  Houses testes  Maintains testes a 3 degrees celcius lower than normal body temperature to protect sperm vitality  Able to respond to temperature change

Mature sperm cell  Only human flagellated cell  DNA is found in the head  20-150 million sperm per mL to be fertile

Semen  Mixture of sperm and accessory gland secretions  Liquid part of semen acts as transport medium for nutrients and chemicals that protect sperm and aid movement (dilutes sperm)  Alkaline pH  Plasmin inhibits bacterial multiplication

Testosterone  The most important hormone of the testes  Produced in the interstitial cells- found between the seminiferous tubules  In puberty, follicle stimulating hormone (FSH) and luteinising hormone (LH) responsible for testosterone production  Responsible for hormonal control of testes

Hormonal control of testes  Hypothalamus stimulates the release of FSH and LH from anterior pituitary gland  FSH stimulates sperm development  LH stimulates interstitial cells to produce testosterone  Levels of testosterone are fed back to hypothalamus and anterior pituitary to regulate sperm production (negative feedback)


Anatomy And Physiology Reproductive System

This system performs a miracle from the conception of life until the birth of the growing life within and it is only proper to be introduced to the main. Women have the responsibility of bringing forth life into the world hence the creation and the function of the female reproductive system.

The Male Reproductive System Anatomy And Phyisiology

Start studying anatomy physiology.

Anatomy and physiology reproductive system. Unlike its male counterpart the female reproductive system is located primarily inside the pelvic cavity. Recall that the ovaries are the female gonads. Anatomy and physiology of male and female reproductive systems chapter summary and learning objectives.

Learn vocabulary terms and more with flashcards games and other study tools. The internal reproductive anatomy includes the uterus two ovaries two fallopian tubes the urethra the pubic bone and the rectum. Recall that the ovaries are the female gonads.

Recall that the ovaries are the female gonads. The uterus contains an inner lining called the endometrium which builds ups and sheds monthly in response to hormonal stimulation. The gamete they produce is called an oocyte.

At fertilization the chromosomes in one male gamete called a sperm or spermatozoon combine with the chromosomes in one female gamete called an oocyte. The function of the male reproductive system figure 272 is to produce sperm and transfer them to the female reproductive tract. 528hz tranquility music for self healing mindfulness love yourself light music for the soul duration.

Unlike its male counterpart the female reproductive system is located primarily inside the pelvic cavity. Let our experienced instructors help you study the different parts and functions of the. Guild of light tranquility music recommended for you.

Well discuss the production of oocytes in detail shortly.

Anatomy And Physiology 2 Reproductive System Cards Diagram

Lab 15 Reproductive System Anatomy Physiology 2040

Technical Issues In Reproductive Health

Anatomy Physiology Of The Male Reproductive System

Fleays Wildlife Reproductive Anatomy And Physiology

Female Reproductive System Anatomy And Physiology Uterus

Solved What Function Notes Previously For The Male Reprod

Anatomy And Physiology Of Animals Reproductive System

Pin By Daffodilcooper On K Medical Anatomy Gross Anatomy

Anatomy And Physiology Of Human Reproductive System

Basic Maternal Health Nursing Anatomy And Physiology Of

Pin By Leo Ayungao On My Saves Reproductive System Female

Anatomy Physiology Of The Male Reproductive System

Chapter 59 Solutions Laboratory Manual For Human Anatomy

Male Reproductive Diagram Reproductive System Anatomy

The Reproductive Systems Ross And Wilson Anatomy And

Anatomy And Physiology Of Male Reproductive System

Chapter 28 The Reproductive System Principles Of Anatomy And

Anatomy And Physiology Of Male And Female Reproductive

Female Reproductive System Diagram Anatomy Physiology

Female Reproductive System Anatomy And Physiology

Anatomy And Physiology Of The Female Reproductive System

27 2 Anatomy And Physiology Of The Female Reproductive

Anatomy And Physiology Help Chapter 28 Reproductive System

The Male Reproductive System Boundless Anatomy And Physiology

Anatomy And Physiology Of Female Reproductive System

Female Reproductive System Wikipedia

Human Physiology The Female Reproductive System Wikibooks

27 2 Anatomy And Physiology Of The Female Reproductive

Anatomy And Physiology Of Animals Reproductive System

Anatomy And Physiology Female Reproductive System In Medical


Human anatomy and physiology:- 2

Endocrine system
1).Functions of the Endocrine System
2).Anatomy of the Endocrine System • Hypothalamus
• Pituitary Gland
3). Hormones the Anterior Pituitary
4). Hormones of the Posterior Pituitary
• Thyroid Gland
• Parathyroid Glands
• Adrenal Glands
5). Hormones of the Adrenal Cortex
6). Hormones of the Adrenal Medulla
• Pancreatic Islets
• Pineal Gland
• Thymus Gland
• Gonads
7). Hormones of the Ovaries
8). Hormones of the Testes
• Other Hormone-Producing Tissues and Organs
• Placenta
9). Physiology of the Endocrine System
• The Chemistry of Hormones
• Mechanisms of Hormone Action
• Control of Hormone Release

✓ Read now

Respiratory System

  • 1).Functions of the Respiratory System
  • 2).Anatomy of the Respiratory System
  • • The Nose
  • • Pharynx
  • • Larynx
  • • Trachea
  • • Main Bronchi
  • • Lungs
  • • The Respiratory Membrane
  • 3). Physiology of the Respiratory System
  • • Respiration
  • 4). Mechanics of Breathing
  • • Respiratory Volumes and Capacities
  • • Respiratory Sounds
  • 5). External Respiration, Gas Transport, and Internal Respiration
  • • Control of Respirations

✓ Read now

Urinary system

  • 1). Functions of the Urinary System
  • 2). Anatomy of the Urinary System
  • • The Kidneys
  • • Ureters
  • • Urinary Bladder
  • • Urethra
  • 3). Physiology of the Urinary System
  • • Urine Formation
  • • Characteristics of Urine
  • • Micturition

✓ Read now

Male reproductive system

1). Internal Structures
• Epididymis
• Vas Deferens
• Seminal Vesicles
• Ejaculatory Ducts
• Prostate Gland
• Bulbourethral Glands
• Urethra
2).External Structures
• Scrotum
• Testes
• Penis

✓ Read now

Digestive system

  • 1).Functions of the Digestive System
  • 2).Anatomy of the Digestive System
  • • Organs of the Alimentary Canal
  • • Mouth
  • • Pharynx
  • • Esophagus
  • • Stomach
  • • Small Intestine
  • • Large Intestine
  • 3).Accessory Digestive Organs
  • • Teeth
  • • Salivary Glands
  • • Pancreas
  • • Liver
  • • Gallbladder
  • 4).Physiology of the Digestive System
  • 5).Activities Occurring in the Mouth, Pharynx, and Esophagus
  • • Activities of the Stomach
  • • Activities of the Small Intestine
  • • Activities of the Large Intestine

✓ Read now

Nervous system

1).Functions of the Nervous System
2).Anatomy of the Nervous System
3).Organization of the Nervous System
• Structural Classification
• Functional Classification
4). Nervous Tissue: Structure and Function
• Supporting Cells
• Neurons
• Central Nervous System
5).Brain
• Cerebral Hemispheres
• Diencephalon
• Brain Stem
• Cerebellum
• Protection of the Central Nervous System
• Meninges
• Cerebrospinal Fluid
• The Blood-Brain Barrier
6).Spinal Cord
• Gray Matter of the Spinal Cord and Spinal Roots
• White Matter of the Spinal Cord
7).Peripheral Nervous System
• Structure of a Nerve
• Cranial Nerves
• Spinal Nerves and Nerve Plexuses
8).Autonomic Nervous System
• Anatomy of the Parasympathetic Division
• Anatomy of the Sympathetic Division
9). Physiology of the Nervous System
• Nerve Impulse
• The Nerve Impulse Pathway
• Communication of Neurons at Synapses
• Autonomic Functioning
• Sympathetic Division
10).Parasympathetic Division


Sperm are released from the body during ejaculation , which typically occurs during orgasm. Hundreds of millions of mature sperm — contained within a small amount of thick, whitish fluid called semen — are propelled from the penis during a normal ejaculation.

Ejaculation occurs when peristalsis of the muscle layers of the vas deferens and other accessory structures propel sperm from the epididymes, where mature sperm are stored. The muscle contractions force the sperm through the vas deferens and the ejaculatory ducts, and then out of the penis through the urethra. Due to the peristaltic action of the muscles, the ejaculation occurs in a series of spurts.



This comprehensive course contains 28 sections with 197 self-grading lessons, including final assessments. The first section is available to try for free.

This Trial Site is for evaluation purposes and for trying out in your LMS only. User names will be visible to everyone using it, so don't use this trial site with real students or for actual assignments! To view each lesson, POP-UPs MUST BE ENABLED in your browser.

UNIT 1: LEVELS OF ORGANIZATION

Unit 1 provides students with a basic understanding of human anatomy and physiology, including its language, the levels of organization, and the basics of chemistry and cell biology. These lessons provide a foundation for the further study of the body. They also focus particularly on how the body’s regions, important chemicals, and cells maintain homeostasis.

  • Compare and contrast anatomy and physiology, including their specializations and methods of study
  • Discuss the fundamental relationship between anatomy and physiology
  • Knowledge Check
  • Describe the structure of the human body in terms of six levels of organization
  • List the eleven organ systems of the human body and identify at least one organ and one major function of each
  • Knowledge Check
  • Explain the importance of organization to the function of the human organism
  • Distinguish between metabolism, anabolism, and catabolism
  • Provide at least two examples of human responsiveness and human movement
  • Compare and contrast growth, differentiation, and reproduction
  • Knowledge Check
  • Discuss the role of oxygen and nutrients in maintaining human survival
  • Explain why extreme heat and extreme cold threaten human survival
  • Explain how the pressure exerted by gases and fluids influences human survival
  • Knowledge Check
  • Discuss the role of homeostasis in healthy functioning
  • Contrast negative and positive feedback, giving one physiologic example of each mechanism
  • Knowledge Check
  • Demonstrate the anatomical position
  • Describe the human body using directional and regional terms
  • Identify three planes most commonly used in the study of anatomy
  • Distinguish between the posterior (dorsal) and the anterior (ventral) body cavities, identifying their subdivisions and representative organs found in each
  • Describe serous membrane and explain its function
  • Knowledge Check
  • Discuss the uses and drawbacks of X-ray imaging
  • Identify four modern medical imaging techniques and how they are used
  • Knowledge Check

An Introduction to the Human Body - Final Assessment


This is the final assessment for An Introduction to the Human Body. (Available when you subscribe.)

TEACHERS: Subscribe to the FULL COURSE today!

The full course includes all 197 lessons, including 28 Final Assessments with Instructor Answer Keys.

Subscribe to unlock the rest of this course in the Blending Space: The Blending Space is your own exclusive teaching space where you can blend all of your resources with a ready-to-use comprehensive course. Use your course right away, or customize it to your needs.

The Blending Space features:

  • Lessons and assessments that automatically grade and report to your LMS grade book
  • Control over each lesson: Schedule, set attempts, re-arrange, hide/show, and use lessons in any order
  • Create new activities and resources
  • Add your own resources
  • Analytics Dashboard with at-a-glance reporting charts, grades, course analytics, student progress, quiz attempts and feedback
  • Free updates and support


Anatomy and Physiology

Chapter 16: Reproductive System
Part A: Male System
1. Gonads
a. Primary sex organs
i. Males = testes
ii. Females = ovaries
b. Produce and secrete
i. Males = sperm
ii. Females = ova (eggs)
2. Male reproductive system overview
a. Testes (2)
b. Duct system
i. Epididymis (2)
ii. Ductus deferens = vas deferens (2)
iii. Urethra (1)
c. Accessory organs
i. Seminal vesicles (2)
ii. Prostate (1)
iii. Bulbourethral glands (2)
d. External genitalia
i. Penis
ii. Scrotum
3. Specialized structures
a. Testes
i. Coverings
1. Tunica albuginea- capsule that surrounds each testis
2. Septa (singular = septum)- extensions of the capsule, divide testis into lobules
ii. Internal structure
1. Lobules contain one to four seminiferous tubules
2. Sperm travels through the rete testis to the epididymis
3. Interstitial cells in the s.t.’s produce androgens (testosterone)
a. Castration removal of testes
b. Duct system
i. Epididymis
1. Comma shaped, tightly coiled tube
2. Functions to mature and store sperm cells (at least 20 days)
3. Expels sperm with the contraction of muscles in walls to the vas deferens
ii. Vas deferens
1. Carries sperm from the epididymis to the ejaculatory duct
2. Passes through the inguinal canal and over the bladder
3. Moves sperm by peristalsis
4. Spermatic cord- cord—ductus deferens, blood vessels, and nerves in a connective tissue sheath
5. Ends in the ejaculatory duct which unites with the urethra
6. Ejaculation—smooth muscle in the walls of the vas create peristaltic waves to squeeze sperm forward
7. Vasectomy- cutting of the ductus deferens at the level of the testes to prevent transportation of sperm
iii. Urethra
1. Extends from the base of the urinary bladder to the tip of the penis
2. Carries both urine and sperm
3. Sperm enters from the ejaculatory duct
c. Semen
i. Mixture of sperm and accessory gland secretions
ii. Advantages of accessory gland secretions
1. Fructose provides energy for the sperm cells
2. Alkalinity of semen helps neutralize the acidic environment of vagina
3. Semen inhibits bacteria
4. Elements of semen enhance sperm mobility
d. Accessory organs
i. Seminal vesicle
1. Located at the base of the bladder
2. Produces thick, yellowish secretion (about 60% of semen)
3. Contains: fructose, vitamin C, and other substances that enhance sperm mobility
ii. Prostate
1. Encircles the upper part of the urethra
2. Secretes milky fluid that:
a. Helps to activate sperm
b. Enters the urethra through several small ducts
3. Enlarged prostate constricts flow through urethra
iii. Bulbourethral gland
1. Pea-sized gland inferior to the prostate
2. Produces thick, clear mucus that
a. Cleanses the urethra of acidic urine
b. Serves as a lubricant during sexual intercourse
c. Secreted into the penile urethra
e. External genitalia
i. Scrotum
1. Divided sac of skin outside the abdomen
2. Maintains testes at 3oC (5oF) lower than normal body temperature to protect sperm viability
ii. Penis
1. Delivers sperm into the female reproductive tract
2. Regions of the penis:
a. Shaft with erectile tissue
b. Glans penis (enlarged tip)- sensitivity
c. Prepuce = foreskin
i. Folded cuff of skin around the proximal end
ii. Often removed by circumcision
3. Internal
a. Three areas of spongy tissue around the urethra
b. Erections occur when this erectile tissue fills with blood during sexual excitement
4. Spermatogenesis
a. Overview
i. Production of sperm cells
ii. Begins at puberty and continues throughout life
iii. Occurs in the seminiferous tubules
b. Spermatogonia = stem cells undergo rapid mitosis to produce more stem cells before puberty
i. Follicle-stimulating hormone (FSH) modifies cell division
1. One cell produced is a stem cell, called a type A daughter cell
2. The other cell produced becomes a primary spermatocyte, called a type B daughter cell
ii. Primary spermatocytes undergo meiosis
1. One primary spermatocyte  four haploid spermatids
2. Spermatids- 23 chromosomes (half as much material as other body cells)
c. Human life cycle
i. Union of a sperm (n or 23 chromosomes) with an egg (23 chromosomes) creates a zygote (2n or 46 chromosomes)
1. N + N = 2N
d. Spermiogenesis
i. Late spermatids develop distinct regions:
ii. Sperm cells result
iii. Entire spermatogenesis process
e. Sperm cell anatomy
i. The only
ii. Three parts
1. Head
a. Contains
b. Acrosome
c. Breaks down and releases
2. Midpiece
3. Tail
f. Testosterone production
i. The most important
ii. Produced in
iii. Luteinizing hormone (LH)
1. This causes
iv. Functions of testosterone
1. Stimulates
2. Underlies
3. Causes
a. Deepening
b. Increased
c. Enlargement
d. Thickening

Chapter 16: Reproductive System
Part B: Female System
1. Overview
a. Ovaries (2)- produce eggs and female sex hormones
b. Duct system (transport):
i. Uterine tubes (fallopian tubes) (2)- egg transport
ii. Uterus (1)- embryo/fetal development
iii. Vagina (1)- copulation, birth canal
c. External genitalia- copulation
2. Ovaries
a. Composed of ovarian follicles (sac-like structures)
i. Oocyte (immature egg)
ii. Follicular cells- surround the oocyte
iii. Follicular stages
1. Primary follicle- contains an immature oocyte
2. Graafian follicle- growing follicle with a maturing oocyte
3. Ovulation- when the egg is mature, the follicle ruptures (about every 28 days)
4. The ruptures follicle is transformed into a corpus luteum
b. Support
i. Suspensory ligaments- secure ovary to laternal walls of the pelvis
ii. Ovarian ligaments- attach to uterus
iii. Broad ligament- a fold of the peritoneum encloses suspensory ligament
3. Duct system
a. Fallopian tubes
i. Receive the ovulated oocyte
ii. Provide a site for fertilization
iii. Attach to the uterus
iv. Little or no contact between the ovaries and uterine tubes
v. Supported and enclosed
vi. Anatomy & physiology
1. Fimbriae
a. Finger-like projections at the distal end of the uterine tube
b. Receive the oocyte from the ovary
2. Cilia
a. Located inside the uterine tube
b. Slowly move the oocyte toward the uterus (takes 3-4 days)
3. Fertilization occurs inside the uterine tube since oocyte lives about 24 hours
b. Uterus
i. Located between the urinary bladder and rectum
ii. Hollow organ- pear shape
iii. Functions
1. Receives a fertilized egg
2. Retains the fertilized egg
3. Nourishes the fertilized egg
iv. Support
1. Broad
2. Round
3. Uterosacral
v. Regions of the Uterus
1. Body- main portion
2. Fundus- superior rounded region above where uterine tube enters
3. Cervix- narrow outlet that protrudes into the vagina
vi. Walls of Uterus
1. Endometrium
a. Inner layer
b. Allows for implantation of a fertilized egg
c. Sloughs off if no pregnancy occurs (mensus)
2. Myometrium- middle layer of smooth muscle
3. Perimetrium (visceral peritoneum)- outermost serous layer of the uterus
c. Vagina
i. Extends from
ii. Located between
iii. Serves as
iv. Receives
v. Hymen
4. External genitalia = vulva
a. Mons pubis
i. Fatty area
ii. Covered with
b. Labia =
i. Majora
ii. Minora
iii. Corresponds to
iv. Majora encloses vestibule
1. Contains external openings of
c. Clitoris
i. Contains
ii. Corresponds to
1. Hooded
2. Composed of
3. Becomes swollen
d. Greater vestibular glands
i. One found on
ii. Secretes
e. Perineum
i. Diamond-shaped defined by:
1. Anterior:
2. Posterior:
3. Lateral:
ii. Urethral orifice
iii. Vaginal orifice
5. Oogenesis and ovarian cycle
a. Total supply of eggs are presented at birth
b. Ability to release eggs begins at puberty
c. Reproductive ability ends at menopause
d. Oocytes are matured in developing ovarian follicles
e. The process and steps of oogenesis
i. Oogonia- female stem cells found in a developing fetus
ii. Oogonia undergo mitosis- oogonia undergo mitosis produce primary oocytes
iii. Cells surrounding primary oocytes form primary follicles in the ovary
iv. Oogonia no longer exist
v. Primary oocytes are inactive until puberty
vi. Follicle stimulating hormone (FSH) causes some primary follicle to mature each month
vii. Cyclic monthly changes
f. Meiosis
i. Starts inside maturing follicle
ii. Produces a secondary oocyte and the first polar body
iii. Development to mature stage takes about 14 days
iv. Secondary oocyte ovulates with the release of luteinizing hormone (LH)
1. Secondary oocyte is release and surrounded by a corona radiate (nurturing cells)
v. Is completed
1. Ovum = egg
2. Two additional
vi. Zygote (fertilized egg) =
vii. If no fertilization
viii. Comparison
1. Males
2. Females
ix. Sperm and egg comparison
1. Sperm
2. Egg


Chapter 16: Reproductive System & Development
Part C: Menstrual cycle, Pregnancy
1. Menstrual (uterine) cycle
a. Overview
i. Cyclic changes of the endometrium
ii. Regulated by cyclic production
iii. FSH and LH regulate the production of estrogens and progesterone
iv. Both female cycles are about 28 days in length
v. Ovulation typically occurs about midway through cycle on day 14
1. However,
b. Stages
i. Menstrual phase
1. Days 1-5
2. Functional layer of the endometrium is sloughed
3. Bleeding occurs for 3-5
4. By day 5 growing ovarian follicles are producing more estrogen
ii. Proliferative
1. Days 6-14
2. Regulation of functional layer of the endometrium
3. Estrogen levels rise
4. Ovulation occurs in the ovary at the end of this stage
iii. Secretory
1. Days 15-28
2. Progesterone levels rise and increase the blood supply to the endometrium
3. Endometrium increases in size and readies for implantation
4. If fertilization does occur:
a. Embryo produces a hormone (HCG) that causes the corpus luteum to continue producing its hormones
5. If fertilization does not occur
a. Corpus luteum degenerates as LH blood levels decline
c. Hormones produced by ovaries
i. Estrogen
1. Produced by follicle cells
2. Cause secondary sex characteristics
a. Enlargement of accessory organs
b. Development of breast
c. Appearance of axillary and pubic hair
d. Increase in fat beneath the skin, particularly in hips and breasts
e. Widening and lightening of the pelvis
f. Onset of menses (menstrual cycle)
ii. Progesterone = the hormone of pregnancy
1. Produced by the corpus luteum
2. Production continues until LH diminishes in the blood
3. Does not contribute to the appearance of secondary sex characteristics
4. Helps maintain pregnancy
5. Prepares breasts for milk production
6. Feedback
d. Mammary glands
i. Present in
1. Modified
ii. Function is
iii. Stimulated by


Anatomy And Physiology Of Female Reproductive System

The Reproductive Systems Ross And Wilson Anatomy And

Anatomy And Physiology Of The Female Reproductive System Pdf

Female Reproductive System Anatomical Chart

15 The Male And Female Reproductive Systems Ppt Video

Anatomy And Physiology Help Chapter 28 Reproductive System

Female Reproductive System Wikipedia

27 2 Anatomy And Physiology Of The Female Reproductive

607 Best Anatomy Images Anatomy Anatomy Physiology

Mcn Anatomy And Physiology Of The Female Reproductive

The Reproductive Systems Ross And Wilson Anatomy And

Female Reproductive System Wikipedia

A09 003 Transparent Female Reproductive System Anatomy And Physiology Models Buy Anatomy And Physiology Models Anatomy Models Physiology Models

Anatomy Physiology Of Female Reproductive System

Male Reproductive System Information Cleveland Clinic

Chapter 27 Female Reproductive System Lecture 19 Marieb S

Structure And Function Of The Female Reproductive System

The Female Reproductive System Boundless Anatomy And

Lesson 15 3 Female Reproductive System Anatomy Physiology

Anatomy And Physiology Of Animals Reproductive System

Fleays Wildlife Reproductive Anatomy And Physiology

Uterus Definition Function Anatomy Britannica

Anatomy Physiology Female Reproductive Anatomy Female

The Female Reproductive System Anatomy And Physiology

Female Reproductive System An Overview Sciencedirect Topics


Book Title: Douglas College Human Anatomy and Physiology II (1st ed.)

Unless otherwise noted, Human Anatomy and Physiology II is © 1999-2016, Rice University. The textbook content was produced by OpenStax College and is licensed under a Creative Commons Attribution License 4.0 License, except for the following changes and additions, which are © 2017 Douglas College Biology Department, and are also licensed under a Creative Commons Attribution License 4.0 License.

The following changes were made to this book:

Under the terms of the CC-BY license, you are free to copy, redistribute, modify or adapt this book as long as you provide attribution.

    If you use this textbook as a bibliographic reference, then you should cite it as follows:


Watch the video: Male Reproductive System Model (June 2022).


Comments:

  1. Lot

    I used to think differently, thanks a lot for the help on this issue.

  2. Brazragore

    In my opinion the theme is rather interesting. Give with you we will communicate in PM.

  3. Nikom

    you were visited simply brilliant idea



Write a message