E2: Reproductive: Male Flashcards

1
Q

Testes

Describe their embryonic development

A
  • Testes develop in a retroperitoneal position attached to the gubernaculum (Dense Regular CT)
  • Fusion of the peritoneum and the gubernaculum allows the vaginal process to form
  • •(outpocketing of the parietal peritoneum)
  • Testes are pulled through the inguinal canal by the regression of the gubernaculum.
  • Closure of the vaginal process (Few weeks before or after birth)
  • Remaining serous membrane wraps around the testis = tunica vaginalis
  • •Visceral & parietal layers of mesothelium
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2
Q

Testes:

Describe the structure of the testes

A
  1. Spermatic cord:
    * Pathway for nerves & blood vessels.
  2. Tunica Vaginalis:
  • Secretes Fluid to provide lubrication
  • Location of potential Hydrocele*
  1. Tunica albuginea
  • CT capsule
  • Divides testis into lobules
    • Lobules contain Seminiferous tubules
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3
Q

Seminiferous Tubules:

Describe the structure & Composition

A

SN tubules are Lined by Germinal Epithelium

  • Spermatogenic cells:
    • Spermatogonia (SG)
    • Differentiating sperm cells
  • Sertoli cells (SC):
    • Nurse cells for developing Sperm
    • Secrete hormones

Interstitium

  • Fibroblasts
  • Myoid Cells: Contractile
  • Leydig cells (interstitial cells)
    • Secrete Testosterone
  • Capillaries

Myoid cell contraction & Sertoli exocrine secretion constantly pushing sperm into Epididymis

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4
Q

Seminiferous Tubules:

Describe the process of Spermatogonia

A

Spermatogonia:

  • Undifferentiated germ cells At the base

Development (2-3 months)

  1. Spermatogenesis
    * Spermatogonia to spermatid
  2. Spermiogenesis
    * Differentiation to mature sperm (spermatozoa)

Spermatogonia – at the base

Spermatids –elongated nuclei – minimal flagellum

Sperm (spermatozoa) – flagella/acrosome

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5
Q

Spermiogenesis

Describe the appearance of Spermiogensis in the SN

What are the components of the mature sperm cell?

A

Components of Sperm Cells:

Flagellum:

•Necessary for movement from vagina to Fallopian tubes

Mitochondria:

•Required energy for the Flagellum

Acrosome (modified lysosome)

•Used to penetrate the egg

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6
Q

Testes/Spermatogenesis

Describe the temperature control process and the major components

A

Why they are outside of the body*

Spermatogensis occurs optimally at ~35 C

•Temperature regulation is mediated through (2) muscles & vasculature

Dartos muscle

  • SM beneath the skin of the scrotum; Changes surface area Contraction → Wrinkling of the Scrotum
  • Relaxation → Smooths out the Scrotum

Cremaster muscle

  • SkM in the spermatic cord; Raises or lowers testis
  • Contraction → Raises Testis
  • Relaxation → Lowers Testis

Pampiniform plexus

  • Venous network in the spermatic cord
  • Counter current exchange system
  • Venous blood carries away heat from adjacent arterial blood as it ascends
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7
Q

Sertoli cells

Describe the function and components

A

Sertoli Cells:

  • Base: Sits on BL
  • Apex: Extends to lumen

Function:

  • Nutrient support
  • Exocrine function
    • Fluid (lowers friction & provides pathway for spermatids to “swim out”
  • Endocrine function
    • Androgen-binding protein (ABP)
    • Inhibin
  • Blood-testis barrier
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8
Q

Interstitium: Leydig Cells

Describe location & function

A

Leydig cells:

  • Located between the tubules
  • Make testosterone; Induces
  • Epiphyseal cartilage closure
  • Facial hair development
  • Increased muscle mass
  • Increased libido
  • Spermatogenesis
  • Erectile function*
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9
Q

Gonadal Hormone Regulation

Positive/Stimulating Reg

Negative/Inhibitory Reg

Consequences of Anabolic Steroids?

A

Positive Regulation

LH → Leydig cells → ↑ testosterone

FSH → Sertoli cells → ABP

Sertoli cells → ↑ activin → ↑ FSH → ↑ ABP

Negative Regulation

Testosterone → hypothalamus → ant pit → ↓ LH → ↓ Testosterone

Sertoli cells → ↑ inhibin → AP → ↓ FSH → ↓ ABP

Consequences of Anabolic Steroids (Androgen doping):

High levels of anabolic steroids induces feedback mechanisms to reduce Fertility

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10
Q

What is the Duct system?

Mnemonic?

A
  1. Seminiferous Tubules
  2. Epididymis*
    1. Convoluted tubule
  3. Vas Deferens
    1. Ampula
  4. Ejaculatory Duct
  5. Nothing
  6. Urethra
  7. Penis

“SEVEn UP”

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11
Q

Epididymis:

Describe the structure & function

A

Epididymis:

•Convoluted duct located behind the testis that serves as the Final maturation & storage site for spermatozoa

Consists of:

  • Head
  • Body
  • Tail

Lined by Pseudostratified columnar epithelium

  • Basal nuclei
  • Apical Stereocilia
  • Function: Increased surface area to Resorb fluid, concentrates sperm

Smooth muscle:

  • Amount increases distally
  • Slow, rhythmic contraction moves sperm down into the tail
  • Intense contractions during ejaculation

Smooth m. & exocrine function of SnT constantly pushing sperm into Epididymis*

Environment limits sperm motility until ejaculation

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12
Q

Vas Deferens

Describe Structure & Function

A

Vas Deferens:

  • Thick muscular tube
  • (3) layers of Smooth Muscle
  • Function: Propel sperm during ejaculation
  • Lined with Pseudostratified columnar epithelium
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13
Q

Accessory glands

What glands are included?

Function?

A

Includes:

  • Seminal Vesicle
  • Prostate
  • Periurethral Glands

Function:

  • Nutrition
  • Propulsion Fluid
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14
Q

Describe the contribution percentages of final sperm volume

A
  • 70% Seminal Vesicle (SV)
  • 25% Prostate
  • <1% Bulbourethral & Urethral glands
  • <5% Testes
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15
Q

Seminal Vesicle

Structure & composition

Products

A

Structure:

  • Fibromuscular wall
  • Mucosa thrown into numerous folds; Pseudostratified Columnar Epithelium
  • (increase surface area)

Major secretions:

  • Fructose: Sperm energy source
  • Prostaglandins: motility enhancers
  • Fibrinogen/semenogelin:
  • Coagulate into a matrix to briefly hold the sperm in place following ejaculation

Androgen-dependent:

•Requires Testosterone (if reduced, it will regress)

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16
Q

Prostate:

Structure, products & function

A

Structure:

  • Walnut-sized gland below the bladder
  • Fibromuscular stroma
  • Leaf-like papillary infoldings of mucosa (Pseudostratified columnar epithelium)
    • Foldings increase w/ age
  • Copora Amylacea: Hyaline Masses in the prostate lumen
    • Increase w/ age & unknown significance

Secretions: Empties into prostatic urethra

  • Polyamines, prostaglandins
  • Prostate-specific antigen (PSA)
  • Semen liquefaction – sperm release

Androgen-dependent*

17
Q

Corpora Amylacea: What are they?

A

Hyaline cartilage masses in the prostate lumen

Increase with age

Significance unknown

18
Q

Describe the structure of the Penis

A

Erectile tissue:

•Each Surrounded by Tunica Albuginea (Darker pink layer)

Corpora Cavernosa (2x)

•Blood vessels, CT, & Smooth m.

Corpus spongiosum (aka Corpus cavernosum urethra)

Glans

  • Distal expansion of the Corpus Spongiosum
  • Covered by the prepuce (foreskin)
19
Q

Describe the Sections of the Urethra

A

Consists of (3) sections:

Prostatic urethra: Transitional epithelium

Membranous urethra: Pseudostratified columnar

Penile urethra: Pseudostratified columnar

  • Stratified squamous distally (glans)
20
Q

Tissue type?

Function?

A

Erectile Tissue: Highly vascularized

21
Q

Describe the differences between the Flaccid & Erectile state (Erectile Hydraulics)

A

Flaccid State: Limited Blood supply to erectile tissue

  1. Smooth m. surrounding helicine arteries is tonically contracted, thereby limiting blood flow
  2. Blood is routed to AV shunts

Erectile state: Psychogenic & reflex factors

  1. Nerves & vascular ECs produce nitric oxide (NO)
  2. NO activates guanylate cyclase (GTP-> increasing cGMP), thereby relaxing vascular Smooth m. surrounding Helicine a.
  3. Vascular spaces in erectile tissue fill with blood
  4. Engorged tissue compresses veins against the tunica albuginea, thereby blocking venous outflow
22
Q

Describe the phases of ejactulation

A

Ejaculation consists of (3) Phases:

  1. Emission phase
    1. SM contractions mix sperm with gland secretions to form semen
  2. Propulsion phase
    1. Reflex contractions of SM, as well as SkM in the pelvic floor, propel the sperm through the urethra
  3. Post-ejaculation
    1. Phospodiesterase 5 (PDE5) degrades cGMP
    2. PDE5 Inhibitors = Viagra, Cialis, Levitra
23
Q

Explain the clinical basis of a hydrocele & where they can occur

A

Hydroceles can occur through:

  • Infection-derived
  • Failure to close Tunica Vaginalis

Usually resolves on it’s own.

Common in newborns – failure to close processus vaginalis (communicating) or impaired absorption (noncommunicating)– usually resolve spontaneously

Adults – age or scrotal injury

24
Q

Crime scene investigation lab tests test for what compounds if they’re testing for semen

A

Semnogelin (from Seminal Vesicle)

Prostate-Specific Antigen (PSA) (from Prostate, duh)

25
Q

Describe the clinical basis & characteristics of Benign Prostatic Hyperplasia (BPH)

A

Benign Prostatic Hyperplasia (BPH):

  • Prostate gland enlargement due to Nodular hyperplasia (proliferation) of both the epithelium & stroma lining the glands
  • Age-associated: (Men)
  • 20% of men @ 40yo
  • 70% of men @ 60yo
  • 90% of men @ 70yo
  • Androgen-dependent:*
  • Blocked by prepubertal castration
  • Treatment:
  • Antiandrogens can be used

Avodart – inhibits [5-alpha reductase] (converts testosterone to DHT).

26
Q

What is a Vasectomy?

Why is Libido unaffected?

Why is Ejaculate volume unaffected?

Where do the sperm go?

A

Vasectomy:

Removal or sealing of the vas deferens

Seals the vas deferens, Testosterone production continues

Ejaculate vol. is unaffected because Testis only contributes <5% of seminal fluid

Sperm die & get absorbed

27
Q

In patients w/ Erectile dysfunction, Viagra targets which enzyme?

A

Viagra inhibits PDE5