Term
| Describe the H-AP-Gonad axes |
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Definition
Hypothalamus produces GnRH
Ant pit stimulated to produce FSH & LH
FSH stims seminiferous tubules to prod sperm
LH stims leydig cells to prod testosterone
Sem tubules prod inhibin, negative feedback on ant pit
Leydig cells prod testosterone neg feedback on ant pit & hypothalamus |
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Term
| What are the stem cells that produce sperm? Where are they found? |
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Definition
spermatogonia
At the outermost region of the seminiferous tubules, against the basement mmb |
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Term
| What do sertoli cells do to protect the germinal cells within the testes? (3) |
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Definition
act as a blood-testis barrier, preventing molecules from freely moving into the area
prevent the body from being sensitized to antigens in the developing sperm to stop autoimmune targeting of the sperm cells
produce FAS ligand which binds to FAS receptor on T-lymphocytes, trigering apoptosis so they cant target the sperm cells |
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Term
| Describe the steps of spermatogenesis |
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Definition
1. Mitosis: diploid spermatogonia give rise to two daughter cells
2. One stays at the basement mmb as a stem cell
3. Other (primary spermatocyte 2n) moves towards lumen of seminiferous tubules
4. First meiotic division: 2 secondary spermatocytes each are n
5. Second meiotic division: 4 spermatids each are n
6 Spermiogenesis: spermatozoa formed |
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Term
| Are spermatids haploid or diploid? |
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Definition
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Term
| Why is meiosis crucial in spermatogenesis? |
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Definition
| Only 1000-2000 stem cells migrate to the embryonic testes, so meiosis ensures that these get replaced so spermatogenesis can continue throughout adult life |
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Term
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Definition
| decreased fertility due to <20million sperm/mL |
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Term
| Are spermatogonia haploid or diploid? |
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Definition
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Term
| How long can sperm live post-ejaculation? |
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Definition
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Term
| What is the role of cervical mucus in assistance spermatozoa? |
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Definition
| help maintain metabolic requirements |
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Term
| What are selective barriers? |
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Definition
cervix & uterotubal junction
barriers which prevent pathogens & sperm from passing easily |
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Term
| The majority of sperm are eliminated within the female by.... |
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Definition
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Term
| what happens to spermatozoa that are damaged or immotile? |
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Definition
| ciliated cells carry them back to the cervix |
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Term
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Definition
changes in the glycoprotein surface of spermatozoa (seminal plasma proteins are removed) brought about by secretions from female reproductive tissues
essential for the sperm to be able to penetrate the egg membrane |
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Term
| When does fertilization start? When is it done? |
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Definition
when the spermatozoa penetrate the corona radiata
mixing of maternal & paternal chromosomes within the egg |
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Term
| What was Sildenafil originally intended to be used for? |
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Definition
| treating chest pain or angina |
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Term
| What does the corpus spongiosum do? |
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Definition
| keeps the urethra from closing during ejaculation |
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Term
| What neurotransmitter mediates increased blood flw to the corpora cavernosa? |
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Definition
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Term
| Describe the physiology of an erection |
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Definition
PNS induces vasodilation of arterioles, blood flow to corpora cavernosa increases
corpus cavernosum compresses reducing bloow outflow
intracavernosal pressure increases
erection results |
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Term
| Describe how nitric oxide promotes relaxing of smooth muscles during an erection |
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Definition
1. NO acts on VSMC activating GTP, producing cGMP
2. cGMP induces closing of Ca2+ channels in VSMC
3. VSMC relaxes causing vasodilation |
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Term
| Viagra inhibits _______ that catalyzes the breakdown of _____. This ______ the availability of ______ promoting an erection |
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Definition
phosphodiesterase
cGMP
increases cGMP |
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Term
What is the link between viagra and hamsters?
How could this apply to human health? |
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Definition
Viagara causes elevated cGMP levels which speeds up the internal body clock of the brain, improving 'jet lag recovery' in hamsters
may help alleviate circadian rhythm disorders caused by shiftwork |
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