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Repro 1
male repro system
22
Physiology
Undergraduate 3
11/03/2015

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Cards

Term
Describe the H-AP-Gonad axes
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
Term
What are the stem cells that produce sperm? Where are they found?
Definition
spermatogonia

At the outermost region of the seminiferous tubules, against the basement mmb
Term
What do sertoli cells do to protect the germinal cells within the testes? (3)
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
Term
Describe the steps of spermatogenesis
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
Term
Are spermatids haploid or diploid?
Definition
haploid
Term
Why is meiosis crucial in spermatogenesis?
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
Term
What is oligospermia?
Definition
decreased fertility due to <20million sperm/mL
Term
Are spermatogonia haploid or diploid?
Definition
diploid
Term
How long can sperm live post-ejaculation?
Definition
80hrs
Term
What is the role of cervical mucus in assistance spermatozoa?
Definition
help maintain metabolic requirements
Term
What are selective barriers?
Definition
cervix & uterotubal junction

barriers which prevent pathogens & sperm from passing easily
Term
The majority of sperm are eliminated within the female by....
Definition
phagocytosis
Term
what happens to spermatozoa that are damaged or immotile?
Definition
ciliated cells carry them back to the cervix
Term
What is capacitation?
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
Term
When does fertilization start? When is it done?
Definition
when the spermatozoa penetrate the corona radiata

mixing of maternal & paternal chromosomes within the egg
Term
What was Sildenafil originally intended to be used for?
Definition
treating chest pain or angina
Term
What does the corpus spongiosum do?
Definition
keeps the urethra from closing during ejaculation
Term
What neurotransmitter mediates increased blood flw to the corpora cavernosa?
Definition
nitric oxide
Term
Describe the physiology of an erection
Definition
PNS induces vasodilation of arterioles, blood flow to corpora cavernosa increases

corpus cavernosum compresses reducing bloow outflow

intracavernosal pressure increases

erection results
Term
Describe how nitric oxide promotes relaxing of smooth muscles during an erection
Definition
1. NO acts on VSMC activating GTP, producing cGMP
2. cGMP induces closing of Ca2+ channels in VSMC
3. VSMC relaxes causing vasodilation
Term
Viagra inhibits _______ that catalyzes the breakdown of _____. This ______ the availability of ______ promoting an erection
Definition
phosphodiesterase
cGMP
increases cGMP
Term
What is the link between viagra and hamsters?

How could this apply to human health?
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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