AVS 472 pt 2

IM BACK IN THE FUCKING BUILDING

What is the purpose of the scrotum?

• Thermosensor

• Dark pink

• Radiator (expands surface area when warm + wrinkles together when cold)

• Protective

• Is made of stratified squamous cells to protect from lacerations and blunt force

What is the purpose of the tunica dartos?

• Smooth muscle that regulates temperature of testes

  • Need to be a couple of degrees lower than average body heat

• Has the ability to contract and stay contracted without fatigue, forces testes to push ups closer to body and descend when warmer

• Androgen dependent (testosterone)

What is a gubernaculum?

• Adhesive structure/connective tissue that’s anchored at distal end of testes

• Prevents testes from spinning (prevents testicular torsion

• Green blob at bottom

What’s a sigmoid flexure and purpose?

• Pink line

• Can react penis within the body and erect

What is A?

Tunica dartos muscle

What is B?

Parietal vaginal tunic

What is C?

Visceral vaginal tunic

What is D?

Tunica albuginea

• Compared to ovary

What is E?

Testicular parenchyma

What is F?

Mediastinum

What is G?

Vas deferens

What is H?

Epididymis (corpus)

What is I?

Scrotal skin

Why is there space between the parietal and visceral vaginal tunic?

Allow them contract/slide up/down

Space called perennial cavity

What is A?

Seminiferous tubule

What is B?

Tunica albuginea

What is C?

Rete testes (within mediastinum)

What is the parenchyma?

• Where sperm is formed

• Made up of serminferous tubules

  • Where sperm develops

What is A?

Caput epididymis

What is B?

Testicular parenchyma

What is C?

Cauda epididymis

What is D?

Mediastinum

What is A?

Spermatic cord

What is B?

Vas deferens

• Where vasectomy happens

What is C?

Corpus epididymis

What is D?

Cauda epididymis

What is E?

Vas efferentia

• 6-12 tubules

What is F?

Caput epididymis

How does sperm mainly move within the the epididymis in the testis?

Smooth muscle contractions

Where is sperm temporarily stored within the testis?

Cauda epididymis

• Holds 4-5 ejaculates worth of sperm

• Where sperm matures

How does sperm move through the vas deferens?

By fluid or perilstalsis

What is the spermatic cord?

• Made up of vascular, lymphatic, and nerve cells

• Heat exchanger

• House cremaster muscle (skeletal muscle)

  • Fight or flight, bring up testes to avoid damage

What is the pampiniform plexus?

• Counter current exchange

• Reduce amplitude of arterial pulses

• Helps create a high —> concentration/gradient to bring testosterone in for spermatogenesis

What is A?

Ureter

What is B?

Vas deferens

What is C?

Ampulla

• Larger version of vas deferent

What is D?

Seminal vesicles

• Secretes fluid + semen

What is E?

Body of prostate

• Controls which tube is open (vas deferens vs bladder)

What is F?

Disseminate prostate

What is G?

Cowper’s gland

What is H?

Bulbospongiosus muscle

• Erection

what is I?

Penile urethra

What is J?

Pelvic urethra

What is K?

Bladder

What is the cap phase?

• Acrostic vesicles spreads/flattens around top/nucleus, still contains digestive enzymes

• Golgi goes closer to where tail is

• Centrioles separate, one becomes head and other half becomes tail itself

• Acronyms

  • AX — adenoma (tail)

  • OAM — outer acrosomal membrane

  • IAM — inner acrosomal membrane

What happens when sperms release digestive enzymes?

• Inner acrosomal membrane (IAM) and outer acrosomal membrane (OAM) fuses with one another

• The fusion itself releases these enzymes

What is the acrosomal phase?

• Maturation of the head

• Acrosome now covers ¾ of nucleus

• Starts to elongate (image B)

• Microtubules more evident (tail)

• Annulus on either side of tail

• Manchette — remaining mitochondria + cytoskeletal structures

• No organelles on top

What is a manchette?

Series of microtubules, associated with nuclear elongation

What is the maturation phase?

• Manchette disappears

• Mitochondria migrate

• Dense fibers form its tail + sheath

• Postnuclear cap is formed

• Middle piece — generates lots of ATP to allow tail to work when motile

What is the order of sperm maturation?

1. Golgi phase — formation of Golgi apparatus

2. Cap phase (acrosome development continues, flagellum elongates)

3. Acrosomal phase (maturation of head, acrosome + machete + elongation)

4. Maturation phase (manchette disappears, mitochondria migrate, postnuclear cap formed)

What is spermation?

When sperm is released

What is cytoplasmic droplet?

• Is in mid piece of sperm when moving to epididymis

• Attached to immature sperm

• If collecting sperm too quickly/too much, there will be cytoplasmic droplet

What is the function of epididymis?

• Fluid absorption

• Membrane changes

• Nuclear + flagellar stabilization

• Motility, fertility

• Cytoplasmic droplet translocation

What is the function of of tail of epididymis>

Store sperm temporarily, smooth muscle contraction upon sexual stimulation

What are functions for accessory sex glands?

• Alterations + packacging

  • Metabolic substrates

  • Surface coatings

  • Transport for sperm

How long does it take to make sperm?

2-3 months

How does spermatogenesis work?

• Sperm goes through 7 stages

• All sperms in different stages of development, don’t move while developing

• Multiple locations in tubules go through same stages

• Stages — specific cellular associations within small segment of the seminiferous tubule (stages differ in different length of time)

  • A’gonia

  • I’gonia

  • 1’cyte

  • 2’cyte

  • Spermatid

What do you call the time required for sperm maturation?

Duration of cycle of the seminiferous epithelium

• Species dependent

• Typical 4.5 cycles required for A1 spermatogonia to become mature spermatozoa

• Some species variation (different length of stages)

What is the bull’s spermatogenesis like?

• Takes 13.5 days

• Creates 61 mil sperm

What is the ram’s spermatogenesis like?

• Takes 10.4 days

• Creates 47 mil sperm

What is the boar’s spermatogenesis like?

• Takes 8.3 days

• Creates 39 mil sperm

What is the stallion’s spermatogenesis like?

• Takes 12.2 days

• Creates 57 mil sperm

What is the man’s spermatogenesis like?

• Takes 16 days

• Creates 75 mil sperm

What is the math to figuring out the spermatogenesis?

• Add all stage lengths

• Times it by 4.5 cycle

What is the spermatogenic wave?

Helps move sperm without overloading the “entrance” of rete testis

• Spermatozoa constantly formed + released into duct system

• Timing of spermatogenesis is staggered throughout seminiferous tubule to prevent overloading exit

• Site of spermiation constantly changing, creates “wave” of sperm release

What is A?

Spermatogonium

What is B?

Sertoli cell

What is C?

Junctional compartment

What is D?

Intercellular bridge

What is E?

Primary spermatocyte

What is F?

Spermatids

What is G?

Basal compartment

What is H?

Adluminal compartment

What is the interstitial tissue?

Vascular system that provides nutrients, oxygen, growth factors, and hormones

What is the blood testis barrier?

• Sertoli cells + associated tight junctions

• Essential for meiosis

• First appears at puberty

• Induced by FSH

• After puberty, maintained by FSH and/or testosterone

What is the tight junction role in meiosis?

• Controls amount of Sertoli cells inside, can manipulate environment

  • Sertoli can enter + complete meiosis

• Destruction of TJ can cause impairment of meiosis (IE heat, heavy metals, endocrine disruptors, pesticides, lack of FSH/testosterone)

What are variations that change sperm production?

• Testis size (larger size testes = more fertile)

• Efficiency of spermatogenesis (mitotic division, degeneration of germ cells)

• Length/time of spermatogenesis

What causes and happens in overpopulation of spermatogonia?

• If there’s no apoptosis (death of sperm)

• Breaches sertoli/tight junctions, kills those cells

• Happens in basal compartment

What are the steps for anaerobic metabolism/glycolysis for sperm metabolism?

• Fructose with hexokinase (adds phosphate) turns to fructose-6-phosphate

  • Glucose can also be used to make glucose-6-phosphate, however sperm prefers fructose

  • Phosphate enzyme can convert glucose-6-phosphate to glucose, which makes it available for another time (futile cycle

• Makes lactate + 2 ATP + 2 H2O

What are steps for aerobic metabolism for sperm metabolism?

• Goes through tricarboxcylic acid cycle

• Makes 36 ATP fructose or glucose

What is ATP used for in sperm?

• Motility (60%) — not needed until after ejaculation

• Substrate cycling (40%) — wasted, futile cycle

• Transcription + translation — there is none after condensation of nucleus (spermatogenesis) and loss of residual body

What is sperm metabolism reliant on?

Temperature

• ATP production increases as temp increases

• Motility increases with temperature

What is the order of transportation of sperm?

1. Seminiferous tubule (made here)

2. Moves to rete testis via bulk fluid flow

3. Goes into vas efferentia via fluid flow and cilia

   1. Where water gets reabsorbed, sperm gets concentrated in cauda, smooth muscle contractions used to move it up to vas deferens

4. Moves through caput through smooth muscle contractions

5. Moves down corpus via contractions

6. Stored temporarily in cauda, moved through contractions

7. From cauda to vas deferens via peristalsis

What is the function of the epididymis?

• Maturation

  • Change in fertility (changes in proteins on surface of sperm head)

  • Develop motility

  • Nuclear condensation

  • Cytoplasmic droplet

• Concentration — removes water (in vas efferens + caput)

• Secretion

  • Testosterone —> dihydrotestosterone (DHT) (influences epididymal function)

    • 5-reductase does this transition

  • Energy substrates (GPC, free fatty acids, carnitine)

  • Glycoproteins, lipids, enzymes

• Transportation — smooth muscle contractions

• Storage — in cauda

What are the hormonal cibtriks