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Endocrinology of the male and spermatogenesis/ Spermatozoa in the female tract

reproduction
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before spermatozoa can be produced certain endrocine requirements must be met
adequate GnRH must be released from Hypothalamus, FSH and LH secretion from the anterior lobe of the pituitary, secretion of gonadal steriods
males do not have a __________
surge centre
male releases ______ in frequent, intermittent bursts that occur throughout the day and night
GnRH
The bursts of GnRH last for a few minutes and cause discharges of _____ that follow GnRH episode
LH
LH episodes last from __________ and occur from 4 to more than 8 times every 24hours
10-20min
concentrations of _____ are lower than ____ but pulses are longer because of the relatively constant secretion of inhibin and longer half-life of FSH
FSH, LH
LH acts on the ______ cells within the testes
legdig
LH acts on the legdig cells within the testes are analogous to the _________ cells of the antral follicle
theca interna
LH stimulates the legdig cells to produce ___________ most of which is converted to ______________
progesterone, testosterone
are the male equivalent of the theca interna cells
legdig cells
are the male equivalent of the granulosa cells
sertoli cells
___________ convert testosterone to estradiol, function poorly understood and exert a neg feedback on the hypothalamus
sertoli cells
takes place within the seminiferous tubules
spermatogenesis
the goals of spermatogenesis are to
provide the male with a continual supply of male gametes, provide genetic diversity, provide billions of sperm each day to max reproduction by both natural and AI service, provide a site where germ cells are not destroyed by the male's immune system
provide the male with a continual supply of male gametes, provide genetic diversity, provide billions of sperm each day to max reproduction by both natural and AI service, provide a site where germ cells are not destroyed by the male's immune system
the goals of spermatogenesis
Spermatogenesis can be divided into 3 phases
proliferation, meiotic phase, differentiation
cell division (mitosis)
proliferation
produce haploid spermatids (meiosis)
meiotic phase
change from a spherical undifferentiated spermatid into a spermatozoon containing a head, flagellum and principal piece
differentiation
role of the spermatozoom is to deliver the males genetic material during
fertilization
differentiation consists of: 4
golgi phase, cap phase, acrosomal phase, maturation phase
= acrosomic vesicle formation
golgi phase
first steps in the development of the acrosome, very early flagellum development
golgi phase
= acrosomic vesicle forming over nucleus
cap phase
a cap forms over the anterior portion of the nucleus, flagellum begins to project towards the lumen of the seminiferous tubule
cap phase
continues to spread and covers 2/3s of the anterior nucleus
acrosomal phase
nucleus begins to elongate, manchette attaches to nucleus, spermatids are embedded in the sertoli cells
acrosomal phase
post nuclear cap develops, mitochandria migrate and cluster around flagellum, spermatozoa are released into the lumen of hte seminiferous tubule
maturation phase
Front 2/3s are covered by the acrosome, contains enzymes
head of spermatozoa
during fertilization the acrosome undergoes a reaction that allows the sperm to penetrate the
zona pellucida
head + tail
spermatozoa
nucleus + acrosome + postnuclear cap
head
middle piece + principal piece + terminal piece
tail
male produces _________ continually and uniformly throughout his reproductive life
gametes
BSE
breeding soundness evaluation
Male potential fertility is determined by 4
his sperm producing capacity, viability of his spermatozoa, # of morphologically abnormal spermatozoa that he ejaculates, # of functionally normal spermatozoa that he ejaculates
_________ is a good estimator of sperm producing ability
testicular size
to determine a males sperm producing capability, it is necessary to collect
several semen samples over time
measuring the _________ of both testes is a good estimate of sperm producing capacity
circumference
the ability to swim progressively forward
motility
spermatozoa are lost from the female tract by 2
phagocytosis (uterus) , retrograde transport
________ stimulates neutrophil recruitment in the female tract
estradiol
sperm transport 2
rapid transport phase and sustained transport phase
high _______ levels stimulate muscularis contractions
estradiol
________ in semen cause increased tone and motility of the uterus and/or the oviduct, enables movement of both semen and uterine fluids
prostaglandins
low viscosity mucus that allows spermatozoa to swim
sialomucin
thick mucus that washes spermatozoa out of the cervix
sulfomucin
cervix may act as a _____ that eliminates non-motile spermatozoa
filter
spermatozoa must reside in the female tract before they acquire fertility, process whereby spermatozoa acquire fertility in the female reproduction tract
capacitation
Fertilization
hyperactive motility, binding to the zona pellucida, acrosome reaction