Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endo/Repro Final > Male Reproductive Physiology > Flashcards

Male Reproductive Physiology Flashcards

1
Q

What is involved in the hypothalamic pituitary testicular axis?

What negative feedback occurs?

A

Hypothalamus: GnRH

Anterior pituitary: FSH, LH

Testes: testosterone, inhibin

Testosterone -> inhibits GnRH, LH
Inhibin and estradiol -> inhibit FSH, GnRH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of the hypothalamic pituitary testicular axis?

A

Phenotypic gender (embryogenesis)

Sexual maturation (puberty)

Testosterone production

Sperm production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is androgen insensitivity syndrome?

Do they produce AMH?

A

XY individual but no testosterone receptors -> no development of male internal/external genitalia

Produce AMH -> no uterine tubes, uterus, or upper vagina

Phenotypic female with short vagina, labia, and clitoris, breasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the main 80% component of testis?

What is their fx and what do they contain?

What is in the other 20%?

A

Seminiferous tubules

Produce sperm; Sertoli cells (supportive), spermatogonia (stem cells), spermatocyes (developing sperm)

CT/interstitial: Leydig cells that produce testosterone, mast cells, macrophages, nerves, blood vessels, lymph vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What stimulates the leydig cells?

What stimulates Sertoli cells?

A

LH

FSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the exocrine fx of the Sertoli cells?

A

Secrete aqueous fluid into the lumen of seminiferous tubules -> sperm transport from tubules to epididymis

Produce androgen-binding protein (ABP) -> binds testosterone and concentrates it in the seminiferous tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the endocrine fx of the Sertoli cells?

A

Produce AMH: regress internal female genital ducts

Produce inhibin: inhibit FSH

Produce aromatase: converts testosterone -> estradiol-17B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the supportive fx of Sertoli cells?

A

Provide nutrients to differentiating sperm (transferrin, Fe, lactate)

Form tight junctions -> blood-tested barrier: prevents immune system from attacking developing sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the fx of leydig cells?

A

Synthesize and secrete testosterone

Can make cholesterol de novo or get it from circulation to make testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the key to the hormonal changes at puberty and what does it cause?

A

Pulsatile GnRH secretion -> causes pulsatile FSH and LH secretion -> causes sex steroid hormone secretion (testosterone)

Continuous secretion of GnRH will not cause these changes (needs to be pulsatile)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What androgens play a role in the male reproductive system?

What do they bind to?

A

Testosterone, DHT

Bind to androgen receptors: DHT has a higher affinity than testosterone

These receptors are in reproductive and non-reproductive tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the pathway of testosterone

A

Active androgen in most androgenic target tissues

Made in leydig cells -> travels to seminiferous tubules where it is absorbed by the peritubular capillaries and enters peripheral circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does testosterone bind to in the seminiferous tubules?

In peripheral circulation?

(Steroid hormone so has to bind to proteins to travel)

A

Binds to androgen-binding protein (ABP) in seminiferous tubules -> concentrates testosterone

60% binds to sex hormone binding globulin (SHBG) -> keeps testosterone inactive

38% Albumin -> weakly active testosterone

2% Free testosterone -> biologically active

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When does testosterone production begin?

What are its actions?

A

7-8 weeks gestation

Initiate development of internal male genitalia (epididymis, vas deferens, seminal vesicles, penis, scrotum)

Later initiates decent of testes

Also important in spermatogenesis and regulation of gonadotropin secretion (negative feedback on GnRH and LH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are testosterone’s actions during puberty?

A 
Growth spurt
Closure of epiphyseal plates
Acne
Increased muscle mass
Deepening of voice
Body hair
Baldness
Libido
Growth of penis and seminal vesicles
Increased BMR
Increased RBC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the actions of DHT during development?

During puberty?

A

External male genitalia (penis, scrotum, prostate)

Sebaceous gland activity (acne), prostate growth, male pattern baldness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is benign prostatic hyperplasia?

How do you treat this?

A

Requires androgens especially DHT

Enlargement for periurethral prostate lobes that compares the urethra -> cause storage and voiding symptoms

Not premalignant

1st: alpha 1 antagonists to relax smooth muscle in the bladder neck and urethra
2nd: 5 alpha-reductase inhibitors (finasteride) that blocks conversion of testosterone to DHT (less DHT, smaller prostate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Testosterone can be converted to ____ by aromatase in peripheral tissues and Sertoli cells.

What are the actions of this androgen?

A

Estradiols/Estrogens

Bone maturation, growth acceleration, breast growth, role in spermatogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is male hypogonadism?

Primary hypogonadism?

Secondary hypogonadism?

A

Decrease in sperm and/or testosterone production

Decrease testosterone and sperm production from testis -> increase in LH and FSH

Decrease in LH and FSH from anterior pituitary -> decrease testosterone and sperm from testis

20
Q

What is Klinefelter syndrome?

What are the effects on leydig cells and seminiferous tubules?

A

Primary hypogonadism

47, XXY

Y chromosome -> male phenotype but abnormal leydig function -> low testosterone -> high LH -> high estrogen

Seminiferous tubule dysgenesis -> infertility and decreased inhibin -> high FSH

21
Q

What type of hypogonadism is caused from a non functioning pituitary tumor?

What are the symptoms?

A

Secondary hypogonadism

Most are silent

Pituitary compression -> low LH and FSH -> low testosterone -> hypogonadism

Mass effects are visual symptoms and HA

22
Q

What is Kallmann syndrome?

What are the symptoms?

A

Secondary hypogonadism

GnRH neurons fail to migrate into the hypothalamus during embryonic development -> low GnRH secretion -> low LH and FSH -> low testosterone

Delayed/absent puberty, infertility, impaired sense of smell (anosmia) because neurons travel through olfactory bulb

23
Q

What is spermatogenesis?

Where does this occur?

When does this occur?

A

Formation of sperm; spermatogonia (immature germ cells present at birth) differentiate into sperm

Seminiferous tubules

Puberty and continues through life

24
Q

What are the three phases of spermatogenesis?

A

Mitotic divisions
Meiotic divisions
Spermiogenesis

25
Q

What occurs during the mitotic divisions of spermatogenesis?

A

Spermatogonia/immature germ cells undergo mitosis -> produce two primary spermatocytes

26
Q

What occurs during the meiotic divisions of spermatogenesis?

How long?

A

Start with primary spermatocytes

Go through two meiotic divisions

1st division: produces two secondary spermatocytes, each with haploid number of duplicated chromosomes

2nd division: produces two spermatids, each with a haploid number of unduplicated chromosomes

28 days

27
Q

What occurs during the spermiogenesis phase of spermatogenesis?

How long?

A

Start with spermatids that undergo nuclear and cytoplasmic changes -> produce mature spermatozoa

21 days

28
Q

What are the parts of the sperm and what are their functions?

A

Head: fertilization;
Contains a nucleus and acrosome (thick cap containing enzymes like hyaluronidase and proteolytic enzymes)

Tail/flagellum: motility;
Contains axoneme (central skeleton of microtubules), mitochondria, and dynein (ATPase to create energy for the tail)
29
Q

What environment do sperm like to live in?

What keeps the sperm in this environment?

What is the life span of a sperm?

A

Slightly alkaline; cool temperature (increased temperatures leads to shorter life span)

Scrotum keeps testes at lower temperature

In testes: 1 month or more
In female genital tract: 1-2 days

30
Q

What are the functions of hormones in spermatogenesis:

Testosterone
LH
FSH
GH
Estrogens
A

Testosterone: growth and division of spermatogonia

LH: stimulation of testosterone

FSH: stimulates Sertoli cells

GH: early division of spermatogonia

Estrogens: also essential for spermiogenesis

31
Q

Describe the pathway/movement of sperm

A

Seminiferous tubules (testes) -> epididymis -> vas deferens -> prostate gland with seminal vesicles and ejaculatory duct -> urethra with bulbourethral glands

32
Q

What is the function of the epididymis?

A

Sperm storage, sperm motility

Secretes fluid containing hormones (testosterone and estrogen), enzymes, and nutrients essential for sperm maturation

Decapacitation: addition of molecules to the membranes to prevent premature acrosomal reaction

33
Q

What is the function of the vas deferens?

A

Sperm storage in the ampulla

Secretes fluid rich in citrate and fructose -> nourishes sperm

34
Q

What is the function of the seminal vesicles?

What is the fx of prostaglandins?

A

Secrete fluid containing fructose, citrate, prostaglandins and fibrinogen

This fluid nourishes the sperm

Prostaglandins are important for fertilization: thin cervical mucus and cause reverse peristalsis in uterus and uterine tubes so sperm can move towards the ovaries

35
Q

What is the fx of the ejaculatory ducts?

How does it prevent the back flow of urine?

A

Empty sperm into prostatic urethra; store semen until ejaculation

Narrows as it enters the urethra

36
Q

What is the function of the prostate gland?

A

Secrete slightly alkaline fluid containing citrate, phosphate, calcium, and enzymes

The fluid neutralizes the acidity of other seminal fluids, improves motility, and aids in fertilization

37
Q

What is the fx of the bulbourethral glands?

A

Secrete a clear fluid for lubrication of the urethra before sperm enter

38
Q

What is the composition of sperm?

How much sperm does each ejaculation contain?

A

10% sperm
60% fluid from seminal vesicles
30% fluid from prostate
Small amount from bulbourethral gland

2-6mL; 35-200 million sperm/mL

39
Q

Describe the pathway for sexual arousal in males?

Areas that can be stimulated in the male?

A

Sensory nerve signals from the glans penis -> pudendal N -> sacral spinal cord

Glans penis, anal epithelium, scrotum, perineal structures, internal structures, psychic stimulation

40
Q

How many erectile bodies are in the male genitalia?

When do the contractile bodies contract? Relax?

A

3

2 corpora cavernosa surrounding central A and 1 corpus spongiosum surrounding urethra

Erectile bodies contract while relaxed

Relax during an erection

41
Q

During an erection, ____ tone predominates.

What neurotransmitters are released?

NO activates ____ leading to ____.

A

Parasympathetic

ACh, nitric oxide and/or vasoactive intestinal peptide (VIP)

cGMP; smooth muscle relaxation

42
Q

What response does NO and other parasympathetic neurotransmitters have on an erection?

A

Arterial dilation -> increased blood flow

Increased intercacavernosal pressure -> cavernosal expansion

Veins compressed by engorged tissue -> reduced venous drainage

43
Q

What can cause erectile dysfunction?

What is used to treat erectile dysfunction and how does it work?

A 
Vascular disease (HTN, DM, atherosclerosis)
Neurogenic, psychogenic, endocrinologic, medication- induced

Phosphodiesterase-5 (PDE-5) inhibitors like sildenafil/viagra

Increase cGMP levels in erectile tissue; preventing its breakdown -> increases smooth muscle relaxation therefore maintaining an erection

44
Q

What is emission?

What controls this?

What occurs when there is sequential peristaltic contraction of the vas deferens smooth muscle?

What closes?

A

Movement of semen toward an ejaculatory duct

Sympathetic control

Semen moves into internal urethra

Internal sphincter of the bladder

45
Q

What occurs during ejaculation?

What muscles contract?

A

Rhythmic contraction of the bulbospongiosus and ischiocavernous muscles around the base of the penis

Increase pressure in genital ducts and urethra

Ejaculation of semen from urethra to exterior

46
Q

What happens when mature sperm come in contact with fluids in the female tract?

A

Capacitation:

Loss of inhibitory factors in seminal fluid

Loss of cholesterol on acrosome -> weaker head of sperm

Increased calcium permeability -> improves mobility and changes in cellular membrane allowing for acrosome to release enzymes

Zona pellucida receptors exposed

47
Q

How does fertilization occur when the sperm meets the egg?

A

Acrosomal reaction:

Acrosomal membrane dissolves and enzymes escape: hyaluronidase breaks down granulosa cell layer surrounding the ovum

Proteolytic enzymes break down tissue cells adhering to the ovum

Create a pathway for sperm to pass through the zona pellucida and enter ovum

Sperm and oocyte cell membrane fuse and genetic material combine

Endo/Repro Final (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions