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OSSF II Final Exam: Questions With Verified Solutions
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OSSF II Final Exam: Questions With Verified Solutions
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OSSF II Final Exam: Questions With Verified SolutionsWhat are the three cells of the testes and their origins? Right Ans - 1.
Sertoli (from coelomic epithelial cells of the gonald ridge)
2. Sperm (spematogonia from yolk sac)
3. Leydig cells (mesenchyme of genital ridge)
Where is the tonic center and what does it do? Right Ans - Hypothalamus of
the male
Small frequent surges of GnRH induce production of LH, which stimulates
production of testosterone
Where is the surge center and what does it do? Right Ans - Hypothalamus
of the female
High amplitude surge of GnRh to produce LH, which is needed for ovulation
What is male puberty? Right Ans - Age at which the majority of males in a
given species/breed exhibit sufficient size and libido and produce adequate
semen and sperm to produce pregnancies
What is the hypothalamus inherently and what happens to it? Right Ans -
Inherently female
Testosterone defeminizes it
How does testosterone affect the developing hypothalamus? Right Ans - 1.
Produced by fetal tissues
2. Converted to estradiol by aromatase in brain
3. Eliminates surge center
What does alpha-fetoprotein do? Right Ans - Binds estradiol, preventing it
from crossing BBB in the CNS, which prevent females from defeminizing their
own brains
What is alpha-fetoprotein, where is it made, and what does it do? Right Ans
- Glycoprotein made by yolk/fetal liver
Carries FA's, regulates fetal blood osmolarity
What are the factors leading to puberty? (3) Right Ans - 1. Metabolic
(major)
,2. Environmental/social cues
3. Genetics/breed
How is puberty inhibited? Right Ans - 1. GnRH neurons in prepubertal male
have increased sensitivity to negative feedback of T
2. Decreased sensitivity as puberty approaches
What happens to the tonic center at puberty? Right Ans - Less sensitive to
negative feedback of testosterone/estradiol
What happens to GnRH at puberty? Right Ans - Frequency and amplitude
increases -> increase LH secretion -> increased testosterone from Leydig cells
What triggers pubertal change in hypothalamic sensitivity to T? Right Ans -
1. Neurons sense changes in BG and FA's
2. Receptors for leptin
3. Certain level of fatness required for puberty
What do accessory sex glands and cells do to testosterone? What enzyme is
required for this? In which sex does this occur? Right Ans - Convert
testosterone to very potent DHT using 5alpha-reductase
Happens in both males and females but females don't have a lot of
testosterone to convert
What are the accessory sex glands? (4) Right Ans - 1. Ampulla
2. Prostate
3. Vesicular gland (not in carnivores)
4. Bulbourethral gland (not in dog)
What is T/DHT necessary for? Right Ans - Growth and maturation
What happens if you remove testosterone? Right Ans - Accessory sex
glands will regress
What substances interfere with GnRH/LH? (3) Right Ans - 1. GnRH vaccine
2. LH receptor agonist (negative feedback via testosterone)
3. LH receptor antagonist (blocks receptor from LH)
,What happens at the initiation of spermatogenesis (2)? Right Ans - 1.
Sertoli cells form blood barrier
2. Seminiferous tubules become hollow
How long is the cycle of seminiferous epithelium? Right Ans - 60 days, so
recent damage will not show up immediately
How long will damage to the seminiferous tubules take to heal? Right Ans -
6-12 weeks
What secretions from the sertoli cells control spermatogenesis (3)? Right
Ans - 1. Inhibin - inhibits FSH
2. Estradiol - inhibits GnRH
3. AMH/MIS (fetal development), in adults may control meiosis
What causes a lot of problems in the seminiferous tubules? Right Ans -
There needs to be an extremely high concentration of testosterone
What is the pattern of blood testosterone levels and why is this important?
Right Ans - Episodic
Prevents metabolic overload of clearance and sustained negative feedback on
GnRH neurons and FSH
What stimulates the sertoli cells? Right Ans - FSH
What produces androgen-binding protein and what is its purpose? Right
Ans - Sertoli
Causes testosterone to become less lipophilic so that it's carried in fluid
(seminiferous tubules) better
What are the 3 components of immune privilege? Right Ans - 1. Anatomical
(complex junctions)
2. Physiological (specialized transport systems)
3. Immunological (blood testis barrier)
Why is it important to know that the testes are an immunologically privileged
site? Right Ans - If sperm enter bloodstream, the body will produce
antibodies against it (autoimmunity)
, What happens during spermiogenesis (5 steps)? Right Ans - 1. Acrosomal
cap and granules form in golgi
2. Centioles form (implantation site for tail)
3. Elongation of nucleus
4. Migration of mitochondria to midpiece
5. Formation of flagella
What are the components of the flagella (3)? Right Ans - 1. Capitulum (fits
into depression in posterior nucleus)
2. Midpiece (mitochondria arranged in helix over axoneme
3. Tail (axoneme with microtubules)
What are the nuclear changes in spermiogenesis? (3) Right Ans - 1.
Elongated and chromatin condensed and keratinized via disulfide links
2. Transcription/translation stops and DNA cannot be accessed
3. Reversed after sperm enters oocyte
What are the two parts of the spermatic cord? Right Ans - Mesoductus
deferens
Mesorchium
Where is the visceral vaginal tunic of the male? Right Ans - On top of the
tunica albuginea
What are the layers of the scrotum? (7) Right Ans - 1. Skin
2. Tunica dartos
3. Spermatic fascia
4. Parietal vaginal tunic
5. Vaginal cavity
6. Visceral vaginal tunic
7. Tunica albuginea
What are the histological layers of the testes? Right Ans - 1. Vaginal cavity
2. Visceral vaginal tunic
3. Tunica albuginea
4. Tunica vasculosa
5. Seminiferous tubules
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