reproductive system

Question 1

what are the 4 functions of the reproductive system?

Answer 1

Produce gametes: the primary function and involves the production of sex cells – sperm in males and eggs (ova) in females.

fertilization - transport and sustain gametes: Once produced, the gametes need to be transported and kept viable for fertilization to occur. The male reproductive system has a system of ducts and glands that store, nourish, and transport sperm to the female reproductive tract. In females, the fallopian tubes transport eggs from the ovaries to the uterus, where they can be fertilized by sperm.

Nurture a developing offspring: If fertilization occurs, the female reproductive system provides a nurturing environment for the developing fetus. The uterus thickens with a lining (endometrium) to house the fertilized egg and provides nutrients and waste exchange through the placenta.

Produce hormones: The reproductive system also plays a crucial role in the hormonal system. Sex hormones like estrogen, progesterone, and testosterone are produced by the gonads and other glands in the reproductive system. These hormones regulate sexual development, menstruation, and other functions related to reproduction.

Question 2

define sexual reproduction

Answer 2

involves the creation of specialized sex cells called gametes.

Question 3

define gamete. what are the 2 types?

Answer 3

haploid cells, meaning they have only one set of chromosomes (half the usual number).
A gamete is a reproductive cell, also sometimes referred to as a sex cell. Gametes are essential for sexual reproduction because they fuse together (forming zygote) during fertilization to create a new organism.

There are two main types of gametes:
Sperm: The male gamete is motile (can move on its own) and typically much smaller than the female gamete.
Egg (Ovum): The female gamete is non-motile (cannot move on its own) and is significantly larger than the sperm cell. It contains nutrients to support the development of the early embryo.

Question 4

define germ cell

Answer 4

Germ cells are the cells that give rise to the gametes (sperm and eggs) in sexually reproducing organisms.

Question 5

define fertilization

Answer 5

Fertilization is the fundamental process in sexual reproduction where two gametes fuse together to create a zygote. The nuclei of the sperm and egg cell fuse, combining their genetic material (chromosomes).

Question 6

define zygote. hoe does it divide? is it haploid/diploid?

Answer 6

It’s a microscopic, single-celled entity formed by the fusion of two gametes: a sperm and an egg.

Unlike most body cells (diploid with two sets of chromosomes), gametes (sperm and egg) are haploid (having one set of chromosomes). When they fuse during fertilization, the zygote becomes diploid, inheriting one set of chromosomes from each parent.

Mitotic Divisions: Each division produces two daughter cells that are genetically identical to the parent zygote.

Question 7

define gametogenesis. how is it called in men and women?

Answer 7

Gametogenesis is the biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. In simpler terms, it’s the way our bodies produce sperm (males) and eggs (females) for sexual reproduction.

Spermatogenesis: This is the formation of sperm in males.
Oogenesis: This is the formation of eggs in females. It’s a more complex process compared to spermatogenesis.

Question 8

define reduction division

Answer 8

the first meiotic division

Question 9

define scrotum. what are the two main functions?

Answer 9

The scrotum is a sac of skin that hangs below the penis and contains the testicles. the scrotum contain smooth muscle called the dartos fascia and cremaster muscle.

Protection: The scrotum’s tough skin and underlying muscle layer help shield the testicles from injury.
Temperature regulation: Sperm production is sensitive to temperature. The scrotum helps keep the testicles slightly cooler than the rest of the body by constricting the muscles in the scrotal wall (making the scrotum appear wrinkled) in cooler temperatures and relaxing them (making the scrotum appear smoother) in warmer temperatures.

Question 10

define dartos muscle.

Answer 10

the scrotum contain smooth muscle called the dartos fascia.
When it contracts, the scrotum wrinkles up (and reduce size) , which helps to conserve heat around the testicles in cold environments. Conversely, when the dartos muscle relaxes, the scrotum becomes smoother and more relaxed, allowing for better air circulation and cooling in warm environments.

Question 11

define cremaster muscle

Answer 11

The cremaster muscle is a thin layer of skeletal muscle that originates from the internal oblique muscle in the lower abdomen and descends down into the scrotum along with the spermatic cord.
The cremaster muscle is involuntary. it contracts in response to stimuli like cold temperatures, pulling the testicles closer to the body for warmth. This reflex is known as the cremasteric reflex.

Question 12

define male gonads (structure and size)

Answer 12

The male gonads are the testes. They are two oval-shaped organs (4-5 cm long) located within the scrotum.

the testes’ structure:
Tunica albuginea: The tough outer layer of the testes that provides protection.
Septum: Connective tissue that divides each testis into lobules.
Lobules: Hundreds (250) of tiny compartments within each testis that house the seminiferous tubules (steroli cells).
Seminiferous tubules: Microscopic tubes where sperm are produced.
Interstitial cells (Leydig cells): Cells located between the seminiferous tubules that produce testosterone.

Question 13

what are the 2 compartments of the lobules?

Answer 13

*intratubular compartment - the seminiferous epithelium of the seminiferous tubule.
*peritubular compartment - interstitial tissue in between the seminiferous tubules. delicate connective tissue that contain clusters of endocrine cells called interstitial cells (Leydig) that produce testosterone.

Question 14

define Leydig cells

Answer 14

are found between the seminiferous tubules within the lobules of the testes. Leydig cells are the primary source of testosterone, the main male sex hormone.
Leydig cells are polygonal-shaped with a large, round nucleus and prominent nucleolus. They contain abundant cytoplasm with lipid droplets, which are essential for testosterone production.

Question 15

define Sertoli cells

Answer 15

Found lining the walls of the seminiferous tubules. Sertoli cells extend from the basement membrane to the lumen (center) of the tubule.

Sertoli cells are like the “nursemaid cells” of the seminiferous tubules in the male testes . They play a vital role in sperm production (spermatogenesis) by providing support and nourishment to developing sperm cells.

Question 16

define androgens

Answer 16

Androgens are steroid hormones that play a key role in the development and maintenance of male sex characteristics in vertebrates . They work by binding to androgen receptors in various tissues throughout the body.

Androgens, primarily testosterone, are responsible for:
Development of male primary sex organs (testes) during fetal development.
Emergence of secondary sexual characteristics in puberty, such as facial and body hair, deepening of voice, and increased muscle mass.
Maintaining sperm production in adulthood.
Sex drive (libido) in males.

Question 17

define epididymis and its functions.

Answer 17

The epididymis is a long, tightly coiled tube located on the backside of each testicle.

*Storage: The epididymis acts as a storage facility for sperm after they are produced in the seminiferous tubules of the testes. Sperm can reside in the epididymis for several weeks.

*Maturation: During their time in the epididymis, sperm cells undergo further maturation. This process involves changes in their structure and function, making them more capable of fertilization (acquiring motility).

*Transport: The epididymis also functions as a transport pathway for sperm. Muscular contractions within the epididymis walls help propel sperm towards the vas deferens, the tube that carries sperm out of the scrotum and up into the abdomen.

Question 18

define rete testis

Answer 18

The rete testis is a network of delicate tubules located in the mediastinum testis, the central area of the testis . It acts as a critical connection point for sperm cells, playing a vital role in their passage from the seminiferous tubules to the efferent ductules.

Question 19

define efferent ductules

Answer 19

The efferent ductules are a series of tiny, coiled tubes that connect the rete testis of the testes to the head of the epididymis.

Question 20

define capacitation

Answer 20

Capacitation is a biochemical process that sperm undergo in the female reproductive tract. It’s the final stage of sperm maturation, essential for them to fertilize an egg.

Question 21

define gametes

Answer 21

A gamete is a reproductive cell, also referred to as a sex cell, of an organism that has undergone meiosis.

There are two main types of gametes:
Egg cells (ova): These are large, immobile female gametes that contain nutrients to nourish the developing embryo.
Sperm cells (spermatozoa): These are small, motile male gametes that can swim to fertilize an egg cell.

Question 22

define meiosis

Answer 22

Meiosis is a cell division process that halves the number of chromosomes in a cell. This means that gametes, unlike regular body cells, only have one set of chromosomes (haploid), while regular body cells have two sets (diploid).

Question 23

define haploid and diploid

Answer 23

Haploid and diploid refer to the number of sets of chromosomes present in a cell’s nucleus.

Haploid (n):
Has one set of chromosomes.
Often referred to as monoploid.
Examples: Sperm cells, egg cells (gametes) in most organisms.

Diploid (2n):
Has two sets of chromosomes.
One set comes from each parent.
Examples: Body cells (muscle cells, nerve cells, etc.) in most organisms.

Question 24

define synapsis

Answer 24

a synapse refers to the pairing of homologous chromosomes that occurs during prophase I of meiosis. This pairing allows for the exchange of genetic material between homologous chromosomes through a process called crossing over.

Question 25

define ductus deference

Answer 25

Ductus deferens (vas deferens) is a part of the male reproductive system. It plays a crucial role in the transportation of sperm.

The ductus deferens is a long, muscular tube that arises from the tail of the epididymis. It travels upwards through the scrotum and inguinal canal into the pelvic cavity behind the bladder.
The ductus deferens joins with the seminal vesicle to form the ejaculatory duct, which then empties into the urethra.

Question 26

define spermatic cord

Answer 26

the spermatic cord is a complex structure that plays a vital role in supporting the testes, transporting sperm, and regulating scrotal temperature.

The spermatic cord is located within the scrotum and extends upwards from the scrotum through the inguinal canal in the abdominal wall and connects to the deep inguinal ring, a muscular opening in the abdominal wall.

The spermatic cord is composed of several key components: vas deferens (ductus deferens), blood vessels, lymphatic vessels, nerves, cremaster muscle and fascia.

Question 27

what is the inguinal canal

Answer 27

The inguinal canal is a passage in the lower anterior abdominal wall, located each side of the body.

Question 28

define ampulla of ductus deference

Answer 28

The ampulla of ductus deferens, also sometimes called the ampulla of vas deferens, is an enlargement or dilated section of the ductus deferens (vas deferens) in the male reproductive system.

Question 29

define seminal vesicle

Answer 29

The seminal vesicle is a paired, sac-like gland that sits behind the bladder and below the rectum in the male reproductive system.
It plays a vital role in semen production by contributing a significant portion of the seminal fluid.
The primary function of the seminal vesicle is to produce a thick, alkaline fluid that makes up a major portion (around 70%) of the total semen volume.

Question 30

define ejaculatory duct

Answer 30

The ejaculatory duct is a short but crucial passage in the male reproductive system. It plays a critical role in directing semen towards the urethra for ejaculation.
It’s formed by the convergence of two ducts:
Duct of the seminal vesicle and Vas deferens (ductus deferens).

Question 31

define urethra

Answer 31

The urethra is a tube-like passage that plays a vital role in both the urinary system and the male reproductive system.

Passage for urine: the urethra is the passage for urine excretion.
Passage for semen: During ejaculation, semen, a fluid mixture containing sperm and fluids from various glands, also travels through the urethra. The ejaculatory duct empties semen into the urethra just before ejaculation.

Question 32

Describe the passage through the ducts of the male reproductive system

Answer 32

Epididymis > Vas Deferens > Ampulla of Ductus Deferens > Seminal Vesicle > Ejaculatory Duct > Urethra

Question 33

what are the glands of the male reproductive system?

Answer 33

Seminal Vesicles, Prostate Gland, Bulbourethral Glands (Cowper’s Glands)

Question 34

define Bulbourethral Glands (Cowper’s Glands)

Answer 34

These are pea-sized glands located near the base of the penis, on either side of the urethra.
They produce a clear, alkaline mucus that is released before ejaculation.

This pre-seminal fluid has several functions:
Lubrication: The mucus helps to lubricate the urethra and neutralize any residual acidity from urine, creating a more sperm-friendly environment.
Neutralization: It may help to neutralize any residual acidic urine in the urethra that could harm sperm.
Sperm transport: The pre-seminal fluid may also help to flush out any debris or obstructions in the urethra, preparing the passage for sperm.

Question 35

define semen
what its pH?

Answer 35

Semen, also known as seminal fluid, is a bodily fluid that plays a critical role in human reproduction. It’s a mixture of several components produced by the male reproductive system:
Sperm: These are the male reproductive cells, essential for fertilization. They are produced in the testes and mature in the epididymis.
Seminal fluid: This fluid makes up the bulk of semen and is produced by various glands - seminal vesicles contribute the largest volume (60%) of seminal fluid, prostate gland that produces a milky fluid (30%), bulbourethral glands that produce a clear, alkaline mucus(5%).
Semen, particularly the fructose from the seminal vesicles, provides sperm with the energy they need to travel through the female reproductive tract and reach the egg.

pH - 6-6.5

Question 36

define Prostate Gland

Answer 36

This walnut-sized gland sits below the bladder and surrounds the urethra.
The prostate gland produces a milky white fluid that contributes to semen volume and has several functions:
*Thinning of semen: Prostate fluid helps to thin the thicker seminal fluid from the seminal vesicles, allowing sperm to move more easily.
*Nutrient supply: The prostate fluid may contain enzymes and other factors that contribute to sperm nourishment and motility.
*Semen liquefaction: Prostate secretions also contain enzymes that help liquefy semen after ejaculation, facilitating sperm movement.

Question 37

describe the Spermatogenesis

Answer 37

Starts with stem cells: Spermatogonia stem cells divide to create new cells - spermatogonium> primary spermatocyte

Meiosis creates haploid cells: Special cell division (meiosis) halves the number of chromosomes, creating genetically diverse sperm - primary spermatocyte> secondary spermatocyte > spermatid

Spermiogenesis shapes sperm: Spermatids transform into mature sperm with a head and swimming tail - spermatid >sperm cell

Release and transport: Mature sperm travel through ducts, maturing further and being stored before ejaculation.

Question 38

what’s the first cell in Spermatogenesis the go through meiosis?

Answer 38

primary spermatocyte

Question 39

define spermatogonia

Answer 39

stem cells.
Spermatogonia (plural: spermatogonia) are the primitive germ cells in the male reproductive system that initiate the process of sperm production (spermatogenesis). They reside near the basement membrane of the seminiferous tubules.

Question 40

define spermatozoa

Answer 40

Spermatozoa are the final male reproductive cells.

Question 41

define incomplete cytokinesis in Spermatogenesis

Answer 41

It allows for the coordinated development, resource sharing, and proper maturation of sperm cells, ultimately contributing to successful sperm production.

In spermatogenesis the process of cytokinesis is incomplete. This means that following cell division, the cytoplasm and some organelles are not completely separated between the daughter cells.
Instead, the daughter cells remain connected by cytoplasmic bridges. Later in spermatogenesis, as the sperm cells mature (spermiogenesis), these cytoplasmic bridges eventually break down, and the sperm cells become fully individual and separated.

Question 42

define intercellular bridge in Spermatogenesis

Answer 42

An intercellular bridge, also sometimes called a cytoplasmic bridge, in spermatogenesis refers to the connection that forms between daughter cells following incomplete cytokinesis.
These bridges are composed of plasma membrane and some shared cytoplasm.

Question 43

how much chromosomes does primary spermatocyte contain?

Answer 43

46 chromosomes each with 2 chromatids

Question 44

how much chromosomes does secondary spermatocyte contain?

Answer 44

23 chromosomes each with 2 chromatids

Question 45

how much chromosomes does spermatid contain?

Answer 45

23 chromosomes each with 1 chromatid

Question 46

define Spermiogenesis (and what happens)

Answer 46

Spermiogenesis is the final stage of sperm development that occurs within the seminiferous tubules of the testes. It’s a complex process where spermatids, the round, immature germ cells transform into mature, motile spermatozoa (sperm) ready for fertilization.

*Nuclear Condensation:
The most prominent change in spermiogenesis involves the dramatic condensation of the spermatid’s nucleus.

*Acrosome Formation:
The Golgi apparatus, a cellular organelle in the spermatid, plays a vital role in forming the acrosome. This cap-like structure at the tip of the sperm head contains enzymes that help the sperm penetrate the egg’s outer protective layer during fertilization.

*Development of the Tail (Flagellum):
The flagellum, the long, whip-like tail of the sperm, is essential for its motility. During spermiogenesis, the flagellum undergoes significant development:
The mitochondria, the cell’s powerhouses, become concentrated near the base of the tail, providing energy for sperm movement.
The microtubules, structural components within the tail, become arranged in a specific pattern, enabling the characteristic whip-like movement that propels the sperm.

*Shedding of Cytoplasm:
Most of the excess cytoplasm surrounding the nucleus and tail in the spermatid is shed during spermiogenesis. This shedding helps to streamline the sperm and reduce its size, making it more efficient for swimming through the female reproductive tract.

Question 47

define acrosome

Answer 47

The acrosome is a specialized structure found on the head of a sperm cell. It plays a critical role in the fertilization process by helping the sperm penetrate the egg’s outer protective layer.
It’s formed during the final stage of sperm development (spermiogenesis) by the Golgi apparatus. The acrosome is filled with a variety of proteins and enzymes (hydrolytic enzymes digest the zona pellucida and other barriers, creating a passage for the sperm to reach the egg’s plasma membrane)

Question 48

does the sperm how mitochondria? why?

Answer 48

yes, behind the head. to provide ATP for movement.

Question 49

what’s the direction in the seminiferous tubules during Spermatogenesis?

Answer 49

The process starts at the basement membrane, the layer closest to the blood supply of the testes. As the cells progress through spermiogenesis, they are gradually pushed towards the lumen, the central cavity of the seminiferous tubule.

Question 50

define blood testes barrier

Answer 50

it’s a specialized structure formed by the tight junctions in the basal compartment between Sertoli cells in the seminiferous tubules.
these tight junctions restrict the free movement of molecules and substances between the bloodstream and the compartment where developing sperm cells reside.

It shields developing sperm cells from potentially harmful substances or immune system components present in the bloodstream.

Question 51

define gonadotropins

Answer 51

Gonadotropins are a specific type of tropic hormone produced by the anterior pituitary gland. They share the general characteristic of tropic hormones – stimulating the function of other glands or tissues. gonadotropins have a more specific target: the gonads, which are the reproductive organs – ovaries in females and testes in males.

Question 52

define tropic hormones

Answer 52

hormones that have other endocrine organ ad their target.

Question 53

what are the 2 main gonadotropins?

Answer 53

1. Follicle-stimulating hormone (FSH):
   *In females, FSH stimulates the development of ovarian follicles containing eggs. These follicles also produce estrogen, a sex hormone that contributes to egg maturation and development of female secondary sexual characteristics.
   *In males, FSH stimulates sperm production in the testes by acting on Sertoli cells, which support and nourish developing sperm cells.
2. Luteinizing hormone (LH):
   *In females, LH triggers ovulation (release of a mature egg) from the dominant follicle. It also stimulates the formation of the corpus luteum, a structure within the ovary that produces progesterone, a hormone important for preparing the uterus for pregnancy and maintaining a menstrual cycle.
   *In males, LH stimulates the production of testosterone by Leydig cells in the testes. Testosterone is essential for sperm development, maturation, and male sexual development and function.

Question 54

define GnRH

Answer 54

GnRH, which stands for Gonadotropin-releasing hormone, is a critical hormone produced by the hypothalamus in the brain. It plays a central role in the regulation of the reproductive system by acting as a releasing hormone for the anterior pituitary gland.

Question 55

what does the hypothalamus produce (reproductive system)?

Answer 55

GnRH

Question 56

what does the anterior pituitary gland produce (reproductive system)?

Answer 56

FSH, LH

Question 57

what does LH do in male reproductive system?

Answer 57

LH acts on Leydig cells, located within the interstitial space of the testes. These specialized cells are responsible for producing testosterone, the primary male sex hormone.
When LH binds to receptors on Leydig cells, it triggers a signaling cascade within the cell. This cascade ultimately leads to increased production of testosterone from cholesterol, the precursor molecule.

Question 58

what does FSH do in male reproductive system?

Answer 58

FSH doesn’t directly interact with sperm cells themselves. Instead, it targets Sertoli cells, specialized cells within the seminiferous tubules of the testes.
When FSH binds to receptors on Sertoli cells, it stimulates their activity and supports spermatogenesis. it is also increases the secretion of inhibin.

Question 59

define inhibin (male reproductive system)

Answer 59

inhibin is a hormone produced by Sertoli cells within the seminiferous tubules of the testes. It plays a crucial role in regulating sperm production through a negative feedback mechanism.

Question 60

define aromatase

Answer 60

Aromatase, also known as estrogen synthase, is an enzyme responsible for a key step in the biosynthesis of estrogens.

Aromatase catalyzes the conversion of androgens (male sex hormones) into estrogens (female sex hormones). The primary androgen it acts on is testosterone, converting it into estradiol, the most important form of estrogen.

Question 61

define ABP (male reproductive system)

Answer 61

ABP stands for Androgen-Binding Protein. It’s a glycoprotein (a protein with attached sugar molecules) produced by Sertoli cells within the seminiferous tubules of the testes. ABP plays a vital role in supporting spermatogenesis (sperm production) by regulating the availability of androgens, particularly testosterone.

Question 62

what is the negative feedback control of hormones in the male reproductive system?

Answer 62

Testosterone has a negative feedback on the secretion of GnHR in the hypothalamus and the secretion of LH and FSH in the anterior pituitary gland.
inhibin has negative feedback on the secretion of FSH in the anterior pituitary gland.

Question 63

define puberty in males

Answer 63

Puberty in males is a period of rapid physical and hormonal changes that mark the transition from childhood to adulthood. It’s triggered by a surge in the production of gonadotropin-releasing hormone GnRH from the hypothalamus in the brain which is less sensitive to the inhibitory effect of the testosterone.

Question 64

define testosterone.
what are the effects of testosterone?
when do the testosterone levels pick?

Answer 64

Testosterone is a steroid hormone produced mainly in the testes of males, with smaller amounts also produced by the adrenal glands.
testosterone levels pick at the age of 20.

Effects on Sexual Development and Function:
*Sperm Production (Spermatogenesis): Testosterone is essential for initiating and maintaining spermatogenesis in the testes. It stimulates the proliferation and differentiation of spermatogenic cells, ultimately leading to the production of mature sperm.
*Secondary Sexual Characteristics: Testosterone is a key driver in the development of male secondary sexual characteristics during puberty. These include facial and body hair growth, increased muscle mass, and a deeper voice.
*Libido and Sexual Function: Testosterone is a critical regulator of libido (sex drive) and erectile function. It influences sexual desire, arousal, and the ability to achieve and maintain an erection.