Regulation of Male Reproduction and characrterisitcs of semen

Question 1

What are the neural reflexes involved in the male repro system?

Answer 1

Neural Reflexes: Afferent Sensory stimulus–> Efferent response
ex. Elevation of scrotum in cold temperature, Ejaculation

Question 2

What are the neuroendocrine reflexes in the male repro system?

Answer 2

Neuroendocrine Reflexes:
Sensory afferent > CNS Neurosecretory Cell > Neurohormone > Target tissue

Question 3

What is involved in testicular descent? What is it dependent on?

Answer 3

Androgen Dependent:
* Regression of cranial Suspensory ligament of the testis during transabdominal migration

• Insulin–like-hormone 3 (Insulin 3) is dependent on Androgen and critical to inguinal-scrotal migration, and development of
  the gubernaculum
• Nucleus of the Genitofemoral nerve > Calcitonin gene related peptide (CGRP) > Gubernaculum contraction to pull testis into scrotum

Question 3

What is involved in thermoregulation and how does it facilitate thermoregulation?

Answer 3

Pampiniform Plexus: Conduction/heat exchange

Tunica Dartos: Proximity to body wall, Surface area

Cremaster Muscle: Proximity to Body wall

Scrotal Skin: Thermoregulation, Sweating, Respiration Rate

Question 4

What are the factors that influence the onset of puberty?

Answer 4

genetics, nutrition and growth, seasonal and social.

Question 5

Wlak through the male endocrinology and hormones

Answer 5

The hypothalamus releases Kisspeptin nd GnRH.

the pituitary realeases LH and FSH.

The gonads release testosterone, estradiol, inhibin and activin.

From the pituitary:
GnRh> LH > leydig cells
GnRH > FSH > Sertoli cells

From the gonads:
Leydig > Testosterone
Testosterone and DHT to epididymis and accesory sex gland function.

sertoli converts testosterone to estradiol, produces inhibin and activin, produces androgen binding protein, and spermatogenesis.

Question 6

What are the libido and breeding behaviors?

Answer 6

Libido center in Sexually dimorphic nucleus of Hypothalamus has estradiol receptors

Testosterone > (Aromatase) > Estradiol

Breeding behavior phases: Precopulatory (Courtship, arousal, erection)

Flehmen response:
Receptivity of female (lordosis)
Vasodilation of penis via biochemical/neuro pathway

Copulatory (Mounting, Intromission, ejaculation)
stimulation of glans penis) > Reflex pathway > ejaculation

Postcopulatory (Dismount, Refractory period, memory) Learned behaviors!

Question 7

Describe 3 benefits of incorporating artificial
insemination into livestock management

Answer 7

• Decreased Disease Transmission & BeCer Biosecurity
• Breed mulDple females with one collecDon
  faster geneDc selecDon, need fewer males.
• Safety:
• Avoid Stallions being kicked by mares,
• Avoid having bulls that are aggressive to handlers
• LogisDcs: Travel, AthleDc CompeDDon, Timing, Death

Question 8

Describe the 5 basic parameters used to evaluate semen
and demonstrate understanding of the techniques used
for evaluation.

Answer 8

• Appearance (Hemospermia, Urospermia, Pyospermia)
• Volume
• Concentration of Sperm
• Morphology of Sperm
• Progressive Motility
• Evaluation for Motility after processing

Question 9

Understand the rationale behind categorizing Sperm
defects as compensable vs. un-compensable

Question 10

What are the components of seminal plasma?

Answer 10

• Lipids, Cholesterol
• Carbohydrates
• Electrolytes/salts/Ions
• Proteins
• Fibronectins
• Spermadhesins
• CRISP’s etc.
• Kallikreins
• Peptides (Cytokines, Enzymes)
• DNA
• RNA (packaged in Exosomes)