Chapter 27: Male Reproductive System Study Guide

Question 1

1) What does it mean that sexual reproduction is biparental?
2) Define gonads

Answer 1

1) Biparental: offspring receives genes from two parents
2) Gonads: primary sex organs that produce gametes (testes and ovaries)

Question 2

Define gamete and zygote

Answer 2

1) Gamete: Sex cells produced by each parent
2) Zygote: A fertilized egg with a combination of both parents’ genes

Question 3

1) The male reproductive system serves to do what?
2) What is the males’ organ of copulation?
3) The female reproductive system serves to do what?
4) What is the females’ organ of copulation?

Answer 3

1) Produce sperm and introduce them into the female body
2) Penis
3) Produces eggs, receives sperm, provides for gametes’ union, harbors fetus, and nourishes offspring
4) Vagina

Question 4

1) What are the primary sex organs?
2) What are secondary sex organs?
3) What are the males’ secondary sex organs?
4) What are the females’ secondary sex organs?

Answer 4

1) Primary: Ovaries and testes; produce gametes
2) Secondary: organs other than gonads that are necessary for reproduction
3) Male secondary: system of ducts, glands; penis delivers sperm cells
4) Female secondary: uterine tubes, uterus, and vagina receive sperm and harbor developing fetus

Question 5

1) What amd where are the external genitalia and what are the external genitalia bordered by?
2) The internal genitalia are located where?
3) What is the exception in males?

Answer 5

1) Located in the perineum, they’re externally visible (except for female perineal accessory glands). Bordered by pubic symphysis, ischial tuberosities, and coccyx
2) In the pelvic cavity
3) Testes and some associated ducts in the scrotum are not in the pelvic cavity

Question 6

1) What are the secondary sex characteristics and when do they develop?
2) Can you give some examples of this seen in both sexes?
3) What about traits that are commonly regarded as male characteristics?
4) What about traits that are commonly regarded as female characteristics?

Answer 6

1) Features that distinguish the sexes and influence mate attraction; develop at puberty
2) Both: Pubic and axillary hair and their associated scent glands, and the pitch of the voice
3) Male: Facial hair, coarse and visible hair on the torso and limbs, relatively muscular physique
4) Female: Distribution of body fat, breast enlargement, and relatively hairless appearance of the skin

Question 7

1) What is androgen-insensitivity syndrome?
2) Genetically, what would their karyotype show?
3) Describe how it affects phenotype.

Answer 7

1) Occasionally, a girl shows all the usual changes of puberty, but fails to menstruate; presence of testes in the abdomen
2) Her karyotype would show XY chromosomes
3) Testes produce normal male levels of testosterone, but target cells lack receptors for it. External genitalia develop female anatomy as if no testosterone were present. No uterus or menstruation

Question 8

1) How many pairs of chromosomes are there?
2) How many pairs of autosomes?
3) How many pairs of sex chromosomes?

Answer 8

1) 23 pairs of chromosomes
2) 22 pairs of autosomes
3) 1 pair of sex chromosomes

Question 9

1) Who determines the sex of the child, the male or the female?
2) All eggs carry what chromosome, X or Y?

Answer 9

1) The male’s sperm type
2) X chromosome

Question 10

1) What is cryptorchidism? How common is it?
2) What are measures that can be taken to correct this?
3) If uncorrected, what this leads to what?

Answer 10

1) Undescended testes; occurs in about 3% of male births
2) In most cases the testes descend during the first year of infancy. If not, testosterone injection or simple surgery can draw testes into the scrotum.
3) Sterility or testicular cancer

Question 11

1) What are the external genitalia of the male?
2) What space do they occupy between the thighs?

Answer 11

1) Scrotum and penis
2) Perineum (the diamond-shaped area between the thighs)

Question 12

1) Describe the scrotum and what is contained within?
2) What type of tissue is the spermatic cord and what is housed in it?

Answer 12

1) A pouch of skin, muscle, and fibrous connective tissue containing the testes
2) A bundle of fibrous connective tissue containing the ductus deferens, blood and lymphatic vessels, and testicular nerve

Question 13

1) Why do the testes have to reside in the scrotum instead of the abdomen?
2) What happens if a male has undescended testes?

Answer 13

1) Because of its cooler environment
2) Then they cannot produce sperm at core body temperature of 37°C; must be held at about 35°C outside the body to produce sperm

Question 14

1) Are the testes endocrine, exocrine or both and why?
2) What are lobules and what do they contain?

Answer 14

1) Both endocrine and exocrine glands; produce sex hormones (endocrine) and sperm (exocrine)
2) The connective tissue septa divides the testes into lobules; lobules contain seminiferous tubules

Question 15

What two tunics cover the testes? Describe each of them

Answer 15

1) Outermost is tunica vaginalis: derived from peritoneum
2) Innermost is tunica albuginea: white fibrous capsule

Question 16

1) What are the 2 cell types that make up the thick germinal epithelium of the seminiferous tubules?
2) Where are the sperm produced?
3) Between the seminiferous tubules are clusters of interstitial (Leydig) cells, what do these produce?

Answer 16

1) Germ cells (becoming sperm) and nurse (sustentacular/sertoli) cells
2) The seminiferous tubules are ducts that make sperm
3) Interstitial (Leydig) cells produce testosterone

Question 17

The germ cells that are in the tubules become sperm, but what is the purpose of the sustentacular (nurse or Sertoli) cells?
Include what two substances they produce that help to regulate sperm production

Answer 17

1) Protect the germ cells, and promote their development
2) Germ cells depend on them for nutrients, waste removal, growth factors, and other needs
3) Produce androgen-binding protein and inhibin which regulate sperm production

Question 18

1) Define rete testes and efferent ductules. Include where each collects sperm from.
2) In tracing the path of sperm, where would they be placed?

Answer 18

1a) Rete testis: collects sperm from seminiferous tubules
b) Efferent ductules: collect sperm from rete testes and transporting it to epididymis
2) Seminiferous tubules > rete testis > efferent ductules > epididymis > ductus deferens

Question 19

1) What is the purpose of the epididymis and what happens if not ejaculated?
2) What is the purpose of the ductus (vas) deferens and ejaculatory duct?
3) What two structures merged to form the ejaculatory duct?

Answer 19

1) Epididymis: Site of sperm maturation and storage. If not ejaculated, they disintegrate and epididymis reabsorbs them
2) Ductus (vas) deferens: Muscular tube passing from scrotum to posterior surface of bladder; duct widens into the terminal ampulla and ends by uniting with duct of the seminal vesicle
3) Ejaculatory duct: Where the ductus deferens and seminal vesicle merge; passes through prostate to empty into urethra

Question 20

1) What are the three region of the male urethra?
2) How does this differ from the female urethra in terms of function?

Answer 20

1) Prostatic, membranous and spongy (penile) urethra
2) The male urethra is used in both reproductive and urinary systems; female urethra is only urinary

Question 21

Can you trace the path of sperm from where it was produced through being ejaculated? Include, the efferent ductules, rete testis, and the three region of the male urethra in your tracing.

Answer 21

1. Seminiferous tubules
2. Rete testis
3. Efferent ductules
4. Epididymis
5. Ductus deferens
6. Ejaculatory duct
7. Urethra: P.M.S.

Question 22

1) What is do the seminal vesicles empty into and what percentage of semen do they make?
2) What do the seminal vesicles contain and why?

Answer 22

1) Empties into ejaculatory duct; forms 60% of semen
2) Contains fructose and other carbohydrates (for ATP production), citrate, prostaglandins, and protein as fuel for the sperm

Question 23

1) What does the prostate gland empty into and what percent of semen does it make?
2) What ions does the prostate contain?
3) What proteins does the prostate gland contain; why?

Answer 23

1) Empties into prostatic urethra; makes 30% of semen (a thin milky secretion)
2) Contains calcium, citrate, and phosphate ions
3) Contains protein that activates stickiness (initially) and protein that liquefies the semen - ½ hour after ejaculated

Question 24

1) During sexual arousal, bulbourethral (Cowper) glands produce what? What is the purpose of this secretion?
2) The fluid also protects the sperm how?
3) What percent of the semen does it form?
4) What composes the last 10% of semen?

Answer 24

1) During sexual arousal, they produce a clear slippery fluid that lubricates the head of the penis in preparation for intercourse
2) Protects the sperm by neutralizing the acidity of residual urine in the urethra
3) Does not significantly contribute to semen volume.
4) The sperm itself and the fluid that came along with it from the testes is the last 10%

Question 25

1) After lung cancer, what is the second most common cancer in men?
2) What makes detection difficult?
3) How do doctors check physically and by sample?

Answer 25

1) Prostate cancer
2) Tumors tend to not obstruct urine flow and go unnoticed until they cause pain
3) Through a digital rectal exam (DRE) (palpated through rectal wall to check for tumors) or diagnosed from elevated levels of prostate specific protein in the blood

Question 26

1) What is benign prostatic hyperplasia (BPH)?
2) What are symptoms of BPH?
3) Men who suffer from this are more prone to what issues?

Answer 26

1) A noncancerous enlargement of the prostate
2) Compresses urethra and obstructs flow of urine
3) Bladder and kidney infections

Question 27

1) What is the purpose of the penis in terms of reproduction?
2) What is the scientific name for foreskin? If this is removed, what is the scientific name for that procedure?

Answer 27

1) To deposit semen into the vagina
2) Prepuce (foreskin): cuff of loose skin surrounding glans which may be removed by circumcision

Question 28

What is the half root, half shaft and glans as it relates to the penis?

Answer 28

1) Half root: The internal part of the penis
2) Half shaft: The external part of the penis, which has the glans (head)

Question 29

What are the names for the three cylindrical bodies of erectile tissue? Include which one the urethra goes through and which is dorsal or ventral

Answer 29

1) Single corpus spongiosum surrounds urethra (ventral)
2) Two corpora cavernosa (dorsal)

Question 30

1) Unlike any other organ system, the reproductive system remains dormant for several years after birth. At age 10 to 12 in most boys and 8 to 10 in most girls, a surge of pituitary ___________ awakens the reproductive system at the onset of puberty.
2) Define adolescence

Answer 30

1) gonadotropins
2) The period from onset of gonadotropin secretion and reproductive development to when a person attains full adult height

Question 31

1) Define puberty
2) Which is longer, puberty or adolescence?
3) What age is the onset of puberty in boys? In girls?

Answer 31

1) Puberty: first few years of adolescence, until the first menstrual period in girls or the first ejaculation of viable sperm in boys
2) Adolescence; lasts until full height is reached
3) 14 in boys and 12 in girls

Question 32

1) During fetal development, what are the testes secreting?
2) After the first trimester (3 months), they become dormant until when?

Answer 32

1) Secrete testosterone in first trimester of fetal development at levels about as high as they are in midpuberty
2) Until puberty

Question 33

What organs are going to work together through hormonal links to maintain reproductive function throughout adulthood?

Answer 33

1) Hypothalamus
2) Pituitary gland
3) Gonads

Question 34

1) As the hypothalamus matures, it begins to produce what hormone?
2) The hormone that the hypothalamus produces travels to the anterior pituitary gland. The anterior pituitary is stimulated to produce what two hormones?
3) Which of those hormones stimulates the sustentacular (nurse or Sertoli) cells to secrete androgen-binding protein (ABP)?
4) Which of those hormones stimulates the interstitial (Leydig) cells to produce testosterone?

Answer 34

1) Gonadotropin-releasing hormone (GnRH)
2) FSH and LH
3) FSH: stimulates nurse (Sustentacular/Sertoli) cells to secrete androgen-binding protein that binds testosterone to stimulate spermatogenesis
4) LH (aka ICSH): stimulates the interstitial (Leydig) cells to produce testosterone

Question 35

What are 6 categories of male symptoms of puberty?

Answer 35

1) Growth of sex organs: Penis, testes, scrotum, ducts, glands
2) Generalized body growth: Limbs elongate, muscle mass increases, and larynx enlarges
3) Increased erythropoiesis, basal metabolic rate, and appetite
4) Pubic hair, axillary hair, and facial hair develop in response to dihydrotestosterone (DHT)
5) Associated scent and sebaceous glands also develop
6) Stimulates sperm production and libido (sex drive)

Question 36

1) Testosterone stimulates a burst of generalized body growth in male puberty. Can you give some examples of this?
2) Dihydrotestosterone (DHT) stimulates development of what?

Answer 36

1) Limbs elongate, muscle mass increases, and larynx enlarges
2) Public hair, axillary hair, and facial hair

Question 37

What 3 factors does testosterone sustain in adulthood?

Answer 37

The male reproductive tract, sperm production, and libido

Question 38

In regards to hormone regulation, high levels of testosterone inhibits what two organs? Include what hormones are also decreasing as a result of inhibiting those organs.

Answer 38

1) Hypothalamus: decreasing GnRH
2) Anterior pituitary: decreasing FSH and LH

Question 39

1) In regards to hormone regulation, high levels of sperm will stimulate release of what hormone and from what cell type? What does this hormone do?
2) Will this reduce testosterone production, sperm production or both? Explain

Answer 39

1) Releases inhibin from nurse (sustentacular, Sertoli) cells which suppresses FSH release
2) Reduces sperm production without reducing LH and/or testosterone secretion

Question 40

In regards to hormone regulation, low levels of sperm will have two effects:
1) It will decrease secretion of what hormone?
2) It will increase section of what hormone?

Answer 40

1) Decreases secretion of inhibin
2) Increases secretion of FSH

Question 41

1) Testosterone levels peak at what age?
2) What else declines as men age?
3) What is erectile dysfunction? What is the common name for erectile dysfunction?
4) What percentage of men in their 60s and 80s have ED?

Answer 41

1) Peak at 20; declines ⅕ of that by 80
2) Decline in number and activity of interstitial cells; sperm counts decline
3) ED (common name: impotence): the inability to produce or maintain an erection sufficient for intercourse
4) 20% of men in 60s and 50% of those in 80s

Question 42

1) Define spermatogenesis.
2) What are the three principle events of spermatogenesis?

Answer 42

1) The process of sperm production in seminiferous tubules
2)
a) Division and remodeling of large germ cells into small, mobile sperm cells with flagella
b) Reduction of chromosome number by one-half
c) Shuffling of genes so each chromosome contains new gene combinations that did not exist in parent (ensures genetic variation)

Question 43

1) What is meiosis? What is achieved?
2) In meiosis, the parent cell is diploid, but the daughter cells are ________ (n) with _____ unpaired chromosomes.

Answer 43

1) Recombines genes and reduces chromosome number, while producing four daughter cells that will become sperm
2) Haploid with 23 unpaired chromosomes

Question 44

1) Define spermatogonia. How do the spermatogonia divide; do they use mitosis or meiosis?
2) What triggers spermatogenesis?
3) What results from spermatogenesis?
4) Is the secondary spermatocyte a diploid or haploid, and what does it result from?
5) What do spermatids result from?

Answer 44

1) A sperm stem cell; by mitosis
2) Puberty
3) One daughter cell of each division remains in the location as stem cell; the other daughter cell migrates away and is on its way to producing sperm, which enlarges and becomes a primary spermatocyte
4) Primary spermatocyte undergoes meiosis I which gives rise to two equal-size, haploid, genetically unique secondary spermatocytes
5) Each secondary spermatocyte undergoes meiosis II dividing into two spermatids; a total of four for each spermatogonium

Question 45

Why is the blood testis barrier necessary to protect the sperm?

Answer 45

The sperm are genetically different from the man that produced them, so his immune system would try to kill them if not for the blood-testis barrier

Question 46

1) Define spermiogenesis
2) Define spermatozoa.

Answer 46

1) Spermiogenesis: four spermatids undergo transformations in which they differentiate into a spermatozoa
2) Spermatozoa: mature sperm

Question 47

What is the purpose of the spermatozoon:
1) head
2) acrosome
3) tail
4) and midpiece?

Answer 47

1) Head: pear-shaped; the nucleus contains haploid set of chromosomes.
2) Acrosome: the enzyme cap over the apical half of the nucleus that contains enzymes that penetrate the egg
3) Tail: motility
4) Midpiece: a part of the tail that contains mitochondria, produces ATP for flagellar movement; principal and endpiece for the majority of the flagella

Question 48

1) Define semen.
2) What are the two requirements for sperm mobility?
3) A typical ejaculation discharges __ to ___ mL of semen, composed of about ___% sperm and spermatic duct secretions, ____% prostatic fluid, ____% seminal vesicle fluid, and a trace of bulbourethral fluid.

Answer 48

1) Semen (seminal fluid): fluid expelled during orgasm
2) Elevated pH and an energy source
3) 2 to 5mL of semen, composed of about 10% sperm and spermatic duct secretions, 30% prostatic fluid, and 60% seminal vesicle fluid, and a trace of bulbourethral fluid

Question 49

Rank the components of semen from most to least abundant

Answer 49

1) Seminal vesicle fluid: 60%
2) Prostatic fluid: 30%
3) Sperm and spermatic duct secretions: 10%
4) Bulbourethral fluid: trace

Question 50

1) What is a normal sperm count range?
2) What range is considered infertility in a male?
3) Coitus, coition and copulation are all scientific names for what?

Answer 50

1) Normal sperm count 50 to 120 million/mL
2) Lower than 20 to 25 million/mL: infertility
3) Sexual intercourse

Question 51

1) Erection and ejaculation use what specific nervous system?
2) Are erections sympathetic, parasympathetic, or both? If both, when is each used?
3) Are ejaculations sympathetic, parasympathetic, or both?

Answer 51

1) Autonomic nervous system
2) Erections: Both sympathetic and parasympathetic
-Sympathetic: in response to visual or sexual thoughts
-Parasympathetic: in response to direct stimulation of the penis or genital region
3) Ejaculations: Sympathetic only