Exam 1 - Male Reproductive Physiology

Question 1

Sperm and testosterone are both produced in the…

Answer 1

testes

Question 2

What are the seminiferous tubules?

Answer 2

densely packed sperm producing portion of the testis that includes both Sertoli cells and developing sperm cells

Question 3

What are the interstitial cells?

Answer 3

located in the connective tissue between loops of the seminiferous tubules, produce testosterone, also called Leydig cells

Question 4

What is spermatogenesis?

Answer 4

conversion of undifferentiated germ cells into specialized sperm cells
(spermatogonia to spermatozoa)

Question 5

When do germ cells appear? Describe the chromosomal composition.

Answer 5

before birth (all of them are present from birth)

46 chromosomes, 2n, 46 chromatids

Question 6

Through mitosis, —– are produced. Describe the chromosomal composition.

Answer 6

primary spermatocytes

46 chromosomes, 2n, 92 chromatids

Question 7

Through meiosis 1, —– are produced. Describe the chromosomal composition.

Answer 7

secondary spermatocytes

23 chromosomes, 1n, 46 chromatids

Question 8

Through meiosis 2, —- are produced. Describe the chromosomal composition.

Answer 8

spermatids

23 chromosomes, 1n, 23 chromatids

Question 9

Through spermiation, —- are produced. Describe the chromosomal composition.

Answer 9

spermatozoa

23 chromosomes, 1n, 23 chromatids

Question 10

In what steps of the cell cycle are the sperm cells diploid (2n) vs. haploid (1n)?
At what stage do the cells move from diploid to haploid?

Answer 10

diploid during mitosis and meiosis 1

meiosis 1 produces haploid cells from diploid cells

haploid in meiosis 2 and spermiogenesis/spermiation

Question 11

What is a karyotype?

Answer 11

prepared during metaphase of mitosis, shows all 46 chromosomes with 22 pairs of autosomal chromosomes and 2 sex chromosomes

Question 12

What is karyokinesis?

Answer 12

division of the cell nucleus

Question 13

What is the basic action completed during mitosis?

Answer 13

separation of the sister chromatids

Question 14

Describe the overall results of mitosis.

Answer 14

In the germ cell, each chromosome has 2 chromatids, and they split apart so that 1 chromatid from each chromosome can go to each of the 2 daughter cells.
One daughter cell maintains the germ cell line, the other daughter moves through the rest of the cell cycle to produce spermatozoa.

Question 15

Describe each step of mitosis

Answer 15

prophase - chromosomes condense (the two chromatids wind up into the X shape)

prometaphase - condense and spindle fibers attach

metaphase - meet in the middle (alignment)

anaphase - away (sister chromatids split apart and move to opposite poles)

telophase - chromosomes decondense and nuclear membrane forms around each “half”

(cytokinesis) - everything splits and 2 daughter cells are formed with identical info and 46 chromosomes each

Question 16

Interphase is the part of the cell cycle where things are (dividing/not dividing).

It includes what phases?
What key event occurs during interphase?

Answer 16

Not dividing

G1, S, and G2

Chromosome duplication

Question 17

What key event occurs during Meiosis 1?

Answer 17

separation of homologous chromosomes

Question 18

What key event occurs during Meiosis 2?

Answer 18

separation of sister chromatids

Question 19

Diploid and haploid only correlates with the number of ——, not the number of —–.

Answer 19

chromosomes, not chromatids (2n always has 46 chromosomes because they are in pairs, 1n always has 23 chromosomes because they are single, but a chromosome can have 1 or 2 chromatids at any time)

Question 20

What do the chromosomes “look like” in a germ cell before mitosis?

Answer 20

There are 46 single strands, 1 from mom and 1 from dad for each of the 23 chromosomes. Therefore, 46 chromosomes, 2n, 46 chromatids

Question 21

What happens in the G1 phase of interphase?

Answer 21

everything except the chromosomes is duplicated

Question 22

What happens in the S phase of interphase?

Answer 22

each chromosome is duplicated (go from each chromosome being a single chromatid to 2 chromatids in an X shape)

Question 23

Describe meiosis 1

Answer 23

begin with a primary spermatocyte that has 46 chromosomes which each have 2 chromatids (92 chromatids)
AKA - 23 pairs of Xs (46 Xs)

prophase - homologous chromosomes condense and pair up, have the chance to cross over

metaphase 1 - homologous chromosomes meet in the middle

anaphase 1 - homologous chromosomes move to opposite poles

telophase 1 - nuclear membrane forms around each set of chromosomes

cytokinesis - full cell division, forms 2 secondary spermatocytes, each ends with 23 chromosomes and 46 chromatids (23 Xs)

Question 24

Describe meiosis 2

Answer 24

begin with a secondary spermatocyte that has 23 chromosomes which each have 2 chromatids (46 chromatids)
AKA - 23 Xs

prophase 2- chromosomes condense, spindle fibers start

metaphase 2 - chromosomes meet in the middle (line up)

anaphase 2 - chromosomes split into 2 chromatids which move to opposite poles

telophase 2 - nuclear membrane forms around each set of single chromatid chromosomes

cytokinesis - full cell division, forms 2 spermatids, each ends with 23 chromosomes that have 1 chromatid each (23 chromatids)

Question 25

What changes during spermiation?

Answer 25

spermatids have cytoplasmic bridges that break, forming individual spermatozoa at the lumen of the seminiferous tubule

Question 26

What is the technical definition of spermiogenesis?

Answer 26

morphological differentiation and packaging that protects chromosomes from environmental damage

Question 27

When spermatozoa are released into the lumen, are they motile?

Answer 27

No

Question 28

What are the parts of the spermatozoa, and what is the basic function of each part?

Answer 28

acrosome - egg penetration tail - motility nucleus - chromosomes mitochondrial sheath - energy

Question 29

How does the temperature of the testes differ from the core body temp?

Answer 29

2 degrees cooler

Question 30

How can temperature affect fertility?

Answer 30

hot tubs, cycling, heated car seats, and tight briefs can temporarily impair fertility

Question 31

What happens if the testes do not descend?

Answer 31

cryptorchidism (failure to descend) can lead to permanent infertility because of irreversible damage to the germ cells

Question 32

What is the duct system for storage and transport of sperm?

Answer 32

seminiferous tubules, epididymis, vas deferens, ejaculatory ducts, and urethra

Question 33

How do sperm move through the seminiferous tubules once they are released?

Answer 33

fluid produced by the Sertoli cells washes the non-motile sperm through the tubules

Question 34

What do the epididymis and vas deferens do? (different functions)

Answer 34

E: store, concentrate, and mature (testosterone dependent) sperm VD: movement of sperm and fluid through the ducts via peristalsis

Question 35

What do the ejaculatory ducts do?

Answer 35

transport of sperm during ejaculation

Question 36

What does the urethra do?

Answer 36

sperm transport during ejaculation urine transport during urination Keep urine and sperm separate

Question 37

What is a vasectomy?

Answer 37

cutting of the vas deferens, sperm are still produced but cannot make it out of the penis

Question 38

Sperm makes up --% of semen

Answer 38

10%

Question 39

Accessory glands contribute --% of semen as seminal fluid

Answer 39

90%

Question 40

What are the three accessory glands?

Answer 40

seminal vesicles, prostate, and bulbourethral glands

Question 41

What do the seminal vesicles produce and how much of the semen do they contribute?

Answer 41

60% of semen prostaglandins fructose semenogelins

Question 42

What do prostaglandins do?

Answer 42

stimulate contraction of the female reproductive tract (aid in movement of sperm)

Question 43

What does fructose do?

Answer 43

primary energy source for sperm after they enter the female reproductive tract

Question 44

What do semenogelins do?

Answer 44

proteins that spontaneously coagulate after ejaculation to form a gel matrix that keep the sperm in the vagina after withdrawal

Question 45

What does the prostate produce and how much of the semen volume does it contribute?

Answer 45

30% semen volume buffers and prostate specific antigen (PSA)

Question 46

What do buffers produced by the prostate do?

Answer 46

alkaline pH promotes viability of the sperm (combat the acidic environment of the female)

Question 47

What does prostate-specific antigen (PSA) do?

Answer 47

enzyme aids breakdown of gel matrix to release sperm (process of liquefaction)

Question 48

What does the bulbourethral gland produce and how much of semen volume does that contribute?

Answer 48

5% of semen volume mucus

Question 49

What does mucus do?

Answer 49

aids lubrication during intercourse

Question 50

How much semen/how many sperm are there per ejaculate?

Answer 50

2-3 mL per ejaculate 60-100 million sperm/mL = about 180 million sperm per ejaculate

Question 51

Testosterone affects the (what number?) but not the semen (?).

Answer 51

number of sperm, not the semen volume

Question 52

Can sperm be stored in the epididymis for very long? Why?

Answer 52

yes, several days relatively inactive and low metabolic demand

Question 53

What is the total time for spermatogonium to become spermatozoa? How many and how often are sperm produced?

Answer 53

64-74 days asynchronous process that yields 100-200 million sperm per day (depends on testosterone)

Question 54

What are oligospermia and azoospermia?

Answer 54

oligospermia: few sperm cells ejaculated (low sperm count), less than 20 million/mL is considered infertile azoospermia: no sperm cells ejaculated

Question 55

What is normal volume, liquefaction time, and viscosity for a semen analysis?

Answer 55

volume - greater than 2 mL liquefaction time - less than 60 minutes viscosity - moderate to low

Question 56

What is normal concentration, motility, and WHO morphology for a semen analysis?

Answer 56

concentration - 20 million per mL motility - more than 50% WHO morphology - more than 15%

Question 57

Liquefaction time would increase if...

Answer 57

prostate-specific antigen decreases semenogelins increase