Lecture 14: 80 - Reproduction 2

Question 1

Hormones are only from the _____ (not prostate or seminal vesicles)

What value is classified as oligospermia?

Testes are normally ____ core temperature.

What type of mechanism allows the heat flow to decrease in the testes but increase near the body? What hormone uses this mechanism but in reverse?

Answer 1

1. testes
2. oligospermia is 20 million or less
3. 1-2 degrees Celsius below
4. Countercurrent
5. Testosterone

Question 2

Define the following:

1. Spermatogensis
2. Spermiogenesis
   - cellular remodeling of what?
3. Spermeation

What is found right next to the area that sperm are produced?

What cells provide nutrients for the sperm?

Answer 2

1. Spermatogenesis - Process of sperm production, includes:
2. Spermiogenesis- cellular remodeling of spermatids into spermatozoa (round to tadpole)
3. Spermeation- extrusion of flagellated spermatozoa into the lumen of the tubule.
4. Right where sperm cells produced, the Leydig cells are right next to it producing Testosterone
5. Sertoli cells make the structure of seminiferous tubule
   - support the gametes with nutritional elements

Question 3

Events in Normal Spermatogenesis:

1. Stems cells that develop into ______ lie along basement membrane of seminiferous tubule (basal compartment)
2. Where are they located?
3. Majority undergo continuous ____ division
4. Minority – committed to further differentiation, undergo ______

Answer 3

1. spermatogonia
2. Spermaotgonia are outside the blood/testis barrier
   - Spermatogonia serve as a pool of undifferentiated cells committed to differentiation
3. mitotic
4. meiosis

Question 4

What happens to the minority of spermatogonia cells that undergo meiosis?

Where does differentiation occur?

Answer 4

After meiosis → mature to spermatozoa

Differentiation to spermatozoa occurs in the INNER (adluminal) compartment

Question 5

Spermatids:

1. Lie near what?
2. Attached to adjoining SERTOLI cells by?
3. Connected to secondary spermatocytes by?
   - what is the purpose of these structures?

Answer 5

1. Lie near lumen of seminiferous tubules
2. Attached to adjoining Sertoli cells by specialized “tight” junctions
3. Connected to secondary spermatocytes by intercellular bridges
   - Synchronizes development of a group of cells, allows sharing of resources. Large enough to pass organelles by microtubule-based transport.

Question 6

What happens in the first division? What type of spermatocytes? What is produced?

What happens in the second division? What is yielded?

Answer 6

First division, occurs in - primary spermatocytes,

***producing daughter cells (secondary spermatocytes) with 23 chromosome pairs

***Second division, occurs in secondary spematocytes yielding

SPERMATIDS with 23 single chromosomes each

• cytoplasmic bridges connect the spermatids
• left as residual bodies

Question 7

What is the progression from spermatogonium to mature spermatozoa?
(7)

When does Meiosis I and II occur?

Answer 7

1. Spermatogonium
2. Spermatogonia
3. Primary spermatocyte
   * * meiotic division I
4. Secondary Spermatocytes
   * * Meiotic Division II
5. Spermatids
6. Differentiating spermatids (loss of residual bodies)
7. Mature Spermatozoa

Question 8

SPERMIOGENESIS

1. Period of extensive remodeling produces _____, which differentiate into flagellated _______.
2. what is condensed?
3. Shrinkage of the ____
4. Formation of the ______**
5. Development of _____

Answer 8

1.spermatids

spermatozoa

2. Nuclear condensation
3. cytoplasm
4. acrosome
5. tail

Question 9

What is the cap of membranes containing digestive enzymes called?

What is spermeation?
Where does this occur?

What is removed and what forms?

Answer 9

ACROSOME

• war head of torpedo
• as sperm hits the egg, dumps digestive enzymes and can burrow through

Spermeation:

1. Process of extruding flagellated spermatozoa in LUMEN of the tubule
2. Most remaining cytoplasm is removed and “residual body” is formed

Question 10

What provides the energy for movement?

What forms as a result of Spermatogenesis?

What forms as a result of Spermeation?

What protects the sperm from the immune system?

Answer 10

Mitochondria

2. 4 spermatids - immature haploid gametes
   - remodeling
3. 4 SPERMATAZOA
   - haploid gametes
   - extruded from lumen

Sertoli cells and their TIGHT JUNCTIONS

Spermiogenesis = making 4 spermatids
SPERMATOGENESIS = whole process

Question 11

What is the function of the following:

1. Epididymus
2. Prostate
3. Seminal Vesicles

Which is responsible for alkaline secretions?

Which stabilizes acrosome

Which secretes prostaglandins? What does this do?

Answer 11

Epididymus;

a) sperm maturation, gain motility, lose cytoplasm
b) reservoir for sperm
c) STABILIZE ACROSOME

Prostate:
2. alkaline secretions to neutralize acidic vaginal secretions

Seminal Vesicle:

3. secretions of PROSTAGLANDINS
   - allow for contraction of uterus and fallopian tubes considered important in sperm movement

Question 12

What is prostatic specific antigen? What is it often used for?

Answer 12

PSA –> used for determining prostate cancer

Question 13

How is the paracrine and endocrine function of inhibit and Activin different.

State both.

What is the neuroendocrine axis?

What is the affect of dopamine and Endorphins on the hypothalamus and GnRH?

Answer 13

INHIBIN
Endocrine:
inhibits the pituitary
paracrine: stimulates testosterone secretion

Activin

endocrine: activates the pituitary
paracrine: inhibits testosterone secretion

2. Hypothalamus
   - GnRH on pituitary
   - release FSH and LH
   male: testosterone
   - negative feedback at PITUITARY and HYPOTHALAMUS
3. Dopamine & Endorphins have a NEGATIVE affect on GnRH

Question 14

Where is GnRH released from?

What is its function?

How do dopamine, endorphins, NE and stress (CRH) affect GnRH?

What type of release is GnRH? (constant/pulsatile)

How can one inhibit FSH and LH secretion knowing the type of secretion pattern?

Answer 14

1. Arcuate N. and Preoptic Area
2. Increases synthesis and secretion of gonadotropics in ANTERIOR pituitary
3. Dopamine, Endorphins, NE, stress INHIBIT GnRH
4. Release of GnRH is pulsatile
   – 8 to 14/24 hrs
5. continuous exposure to GnRH is inhibitory to FSH and LH release

Question 15

GnRH receptors on gonadotrophs… activation triggers _____ of stored trophic hormones and stimulates transcription of _____ and ___

What is the major regulator of LH?

What is this hormone converted to in the hypothalamus?

Why do steroid abusing bodybuilders shut down GnRH release? How do they do this?

Answer 15

1. exocytosis
2. LH and FSH -subunit genes
3. testosterone
4. estrogen
5. inject hCG to mimick LH action after finishing T doses to recover endogenous steroidogenesis.
   - stimulates testes to make more testosterone

Question 16

What stimulates Leydig cells to secrete TESTOSTERONE?

What does this hormone bind?

What does it activation?

What does it increase expression of? (important in steroidogenesis)

Answer 16

1. LH
2. binds G protein coupled receptor
3. activates PKA = increase gene transcription to support testosterone synthesis
4. increases expression of sterol-carrier protein & sterol activating protein

Question 17

Sertolli cells are stimulated by ____ and ____ to facilitate the development of what?

Describe the actions of FSH on the cell:

What is the effect?

Answer 17

1. Androgens & FSH
2. Sperm development
3. binds G protein
   - PKA increeases gene transcription
   - increased proteins (ABP - androgen binding proteins)
4. Keeps testosterone high near developing sperm

Question 18

State the major functions of FSH. (6)

Sertoli cells? (3)

Answer 18

1. increase ABP
2. keeps T high near developing cells
3. increases androgen receptors
4. activates AROMATASE (T to E2)
5. increases growth factors to stimulate spermatogonia, spermatocytes, spermatids, motility
6. increases INHIBIN synthesis

Sertoli:

1. Mechanical support
2. Secrete anti-mullerian hormone
3. Contributes to the blood testes border

Question 19

What makes aromatase and increases inhibit synthesis?

Answer 19

FSH

Question 20

How does FSH influence Leydig cell function indirectly?

How does action & inhibit affect T secretion?

What cells do the Leydig cell TESTOSTERONE stimulate?

Describe the positive feedback of testosterone?

Answer 20

Via Inhibin, Activin

2. Activin - inhibits secretion
   Inhibin - activates secretion
   (opposite endocrine)
3. Peritubular myoid cells
4. Sertoli cells
   - both stimulated by testosterone

As testosterone increases, inhibin increases
- Activin and E2 from Sertoli cells decreases T from Leydig cells

• inhibin activates leydig cells
• activin inhibits

Question 21

What happens if spermatogenesis is too fast?

What is released? By what cells?

Answer 21

The developing germ cells release signals to the SERTOLI cells which increase INHIBIN RELEASE

-

Question 22

Decreased inhibin leads to an increase in what?

Answer 22

If spermatogenesis is too slow then the “brake” is relieved. Signaling from spermatogonia, primary spermatocytes, spermatids, and spermatazoa is decreased…

decreased inhibin leads to an increase in FSH, resulting in an increase spermatogenesis

Question 23

Erection is primarily under control of what?

What is relaxed?

Blood flow is increased in what?

Engorgement compressed what?

What do parasympathetic post-ganglionic nerves release? Describe how this works.

Answer 23

1. Parasympathetic
2. smooth muscle (corpora cavernosa and corpus spongiosum)
3. increased flow in cavernous tissue
4. engorgement compresses the DORSAL vein and creates swelling
5. Parasympathetic nerves release Ach and NO
   - Ach binds to muscarinic receptors, activates PLC and increases Calcium which activates NO synthase –> increases NO

OR directly released from nerve terminals

Question 24

NO stimulates guanylyl cyclase, producing ______ that leads to vasodilation
(the action of sildenafil [Viagra] is to inhibit specific _________)

What nerve activity is decreased?

Somatic nerves stimulate striated penile muscles causing greater ______ (ischiocavernosus muscle and bulbospongiosus)

Answer 24

1. cGMP
2. phosphordiesterases that break down cGMP
3. PREASURE

Question 25

What two muscles are important in creating tumescence? Which surrounds the urethra?

Answer 25

1. Corpus cavernosum and corpus spongiosum 2. Corpus spongiosum surrounds the urethra - keeps the urethra open to allow sperm to enter

Question 26

Emission is primarily under control of what? What is emission? Direct innervation of what receptors

Answer 26

1. Sympathetic control 2. Emission – movement of ejaculate into the prostatic/proximal part of urethra 3. Alpha- adrenergic receptors ** some parasympathetic contribution to secretions**

Question 27

What are 4 types of PRIMARY goal abnormalities in HYPERGONADOTROPIC HYPOGONADISM?

Answer 27

1. Acquired (irradiation/orchitis/castration) 2. Chromosomal a) Klinefelter's and variants b) true hermaphrodism 3. Defective Androgen Synthesis (5a - reductase 17a - hydroxylase) 4. Testicular Agenesis

Question 28

What are the levels of LH, FSH and testostrone/DHT in Hypergonadotropic Hypogonadism?

Answer 28

1. Increased LH 2. Increased FSH decreased testosterone, DHT

Question 29

What type of gonadal abnormality is Klinefelter's syndrome? What are the symptoms? What are the levels of FSH, LH, and testosterone?

Answer 29

XXY syndrome HYPERGONADOTROPIC hypogonadism destruction of testes - hard scar tissue = no testosterone therefore FSH AND LSH IS HIGH since testosterone is low

Question 30

What are the levels of LH and FSH and testosterone/DHT IN HYPOGONADOTROPIC HYPOGONADISM? State 6 examples

Answer 30

1. decreased LH 2. Decreased FSH decreased testosterone, DHT 1. panhypopituitarism (congenital or acquired) 2. hypothalamic syndrome 3. LH or FSH deficiency (KALLMAN'S syndrome) 4. hyperprolactinemia 5. Malnutrition and anorexia nervosa 6. Drug induced suppression of LH ( androgens, estrogen, tranquilizers, antidepressants)

Question 31

What is Kallman's syndrome?

Answer 31

low LH or FSH HYPOGONADOTROPIC HYPOGONADISM

Question 32

What are two reasons Pseudohermaphroditism might develop?

Answer 32

1. Complete androgen insensitivity * male pseudohermaphrodism* 2. Incomplete androgen insensitivity a) testosterone receptor defect b) testosterone post receptor defect c) 5a-reductase deficiency

Question 33

What is male infertility? What is it most likely due to? Causes? (2) What is impotence?

Answer 33

1. condition of decreased fertility w/o any clinical manifestations of androgen deficiency. 5-10% of males 2. Due to androgen deficiency 1. altered testosterone biosynthesis in TESTES 2. defects in seminal tract or plasma (more sperm maturation or motility) ~ impotence is the persistent inability for functional erection

Question 34

The fundamental reproductive unit of the ovary is the _____ Consists of one oocyte surrounded by a cluster of ______

Answer 34

1. follicle | 2. ranulosa cells.

Question 35

The following describes functions of what? When fully developed it will: 1. Maintain and nurture the resident oocyte 2. Mature the oocyte and release it at the appropriate time 3. Prepare the vagina and fallopian tubes for fertilization (ENDOCRINE FUNCTION) 4. Prepare the uterine lining to accept and implant a zygote 5. Maintain hormonal support for the fetus until the placenta achieves this capability

Answer 35

GRANULOSA CELLS

Question 36

The number of oocytes continuously _______ from birth (in contrast to male) Through the first 20-24 weeks gestations, germ cells produce oogonia by ____. Some of these oogonia begin prophase of ______ and become PRIMARY oocytes. Prophase will last until just before _____ – 12-40 years later At 6 months after birth, all oogonia become ______ What happens in prophase?

Answer 36

1. declines 2. mitosis 3. meiosis 4. ovulation 5. primary oocytes In prophase no other divisions occur, atresia begins and numbers steadily decline.

Question 37

What are the stages of development? What is the secondary follicle under the influence of? What defines the grafiaan follicle? What is the zone pellucida?

Answer 37

1. Primordial follicle 2. Primary follicle - differentiate into granolas cells - oocyte enlarges 3. Secondary follicle - under influence of FSH cohort - ONE BECOMES GRAAFIAN FOLLICLE ANTRUM in center --> fluid filled space **Zona pellucida – mucopolysaccharide immediately around the oocyte formed by granulosa cells (egg shell protecting egg)**

Question 38

Graafian Follicle: 1. How many? 2. What is the the stem of granulosa cells that connect the cell to the wall of the ovary? 3. What happens once the mucopolysaccharides begin to depolymerize?

Answer 38

1. SINGLE follicle becomes dominant 2. Cumulus oophorus 3. Osmotic pressure increases - granolas cells of cumulus ephors loosen

Question 39

What structure does the following: 1. Connects the egg to the wall of the ovary 2. surrounds and protects the egg 3. provides nutrients

Answer 39

1. cumulus oophorus 2. zona pellucida 3. granulosa cells

Question 40

OVULATION: Rupture of the ______ - release of oocyte to peritoneal cavity Proteolysis of _______. Oocyte is drawn into the fallopian tubes by the actions of _____. Initial _____ division is completed Remaining recruited follicles that failed to dominate undergo _____ Granulosa and Theca cells remain in the follicular cavity as_____

Answer 40

1. follicle 2. basement membrane 3. fimbriae 4. meiotic (first polar body degenerates, secondary oocyte prevails) 5. Meiotic 6. atresia 7. corpus luteum

Question 41

What is the function of corpus luteum?

Answer 41

makes progesterone and estradiol

Question 42

____ and _____ cells undergo leutinization – differentiate, hypertrophy and accumulate large lipid droplets giving characteristic yellow-brown color What does the corpus lute secrete? What happens if no fertilization, corpus luteum regresses, becomes necrotic? What is the name of the fibrous scar tissue that forms?

Answer 42

1. Theca & granulosa - progesterone 2. Luteolysis 3. Corpus Albicans: fibrous scar tissue formed.

Question 43

What makes Inhibin B? What makes Inhibin A?

Answer 43

B = DOMINANT FOLLICLE A = corpus luteum - Inhibin: Always 1 subunit + A or B Produced by granulosa cells of follicle, pituitary, brain, adrenal Kidney, bone marrow.

Question 44

_____ stimulates granulosa cells. ______ inhibit FSH release by gonadotrophs Follistatin – neutralizes ______

Answer 44

1. FSH 2. inhibin 3. activin

Question 45

What enzyme produces estradiol? What converts testosterone to DHT?

Answer 45

Aromatase 5a - reductase

Question 46

How are estrogens metabolized? Describe it for estradiol & progesterone

Answer 46

1. Mainly hepatic processing Estradiol/Estrone - Estrone Sulfate for biliary and urinary excretion Progesterone - Pregnanediol - glucoronide conjugation - excretion

Question 47

How is estrogen transported? How is progesterone transported?

Answer 47

1. SHBG - estradiol increases SHBG 2. Progesterone via CBG - illustrate the point that HYDROPHOBIC THINGS CANNOT EASILY DISSOLVE AND FLOAT AROUND