PHY3181 Theme 4: Applied Reproduction Exam
With Complete Solutions
Reduced fertility - trauma and disease - ANSWER
What are the four key plays in reproductive function? - ANSWER Nerves, hormones,
smooth muscle, secretory tissue
Are nerves important in female reproductive function? - ANSWER Not as much as in
males.
What basal requirements regarding second messengers are necessary for relaxation of
smooth muscle? - ANSWER In order for relaxation to occur we need to get rid of
calcium. Work through cAMP and cGMP and induce activation of PKA and PKG
What can PKG/PKA do generally in the relaxation of smooth muscle/prevention of
contraction? - ANSWER 1. send calcium away into storage
2. kick calcium out
3. induce hyperpolarisation
What can PKA phosphorylate to aid in smooth muscle relaxation? - ANSWER 1. Plasma
membrane calcium pumps
2. ER Ca2+ pumps
3. MLCK
4. K+ channels
How does cAMP/PKA evoke SM relaxation? - ANSWER Hormone binds to the receptor
causing G protein dissociation = activation of adenylate cyclase, = increase in PKA =
phosphorylates K channel = hyper polarisation = Ca2+ channel close = no calcium
entering = relaxation.
How does calcium ellicit a contraction? - ANSWER Calcium binds to calmodulin =
activates the myosin light chain kinase (MCLK) = myosin/actin overlap = contraction
PKA/PKG can prevent a contraction from happening. How does this occur? - ANSWER
PKA can phosphorylate MLCK. This prevent it from binding to the CA2+/CaM complex
and inducing a contraction.
This is what occurs in erection.
What are the sympathetic neurotransmitters? - ANSWER NA, ATP
,What is the parasympathetic neurotransmitter for relaxation? - ANSWER NO
What are the sensory transmitter? - ANSWER NPY, CGRP (both important for female
lubrication; CGRP important in ERECTION)
Describe NA and Ach synthesis. - ANSWER NA synthesized in the vesicles and second
last product of NA put into vesicles and final synthesis occurs within vesicle and so this
requires ATP
Acetylcholine for parasympathetic synthesized in the cell body and then final product is
put into the vesicles
What types of receptors are found in smooth muscles? - ANSWER - junctional receptors
(RACs: these are fast acting receptors - occur only in vas deferens)
- alpha-AR extra-junctional receptors (7 mem-spanning - GPCR - usually have
noradrenaline as ligand, allow a small number of neurotransmitter to induce large effect
to give good contraction through signal transduction)
- P2X receptors - ATP receptors adapted for ATP activity
Which receptor does ATP act on? - ANSWER P2X
What is speed of ejaculation dependent upon? - ANSWER Strength of smooth muscle
contraction (ATP2PTX INTERACTION).
Describe neuroeffector transmission. - ANSWER Nerves come in to smooth muscle -
vesicles containing noradrenaline release the NA, ATP and ACH onto smooth muscles
What are the two innervators for vas deferen contraction for ejaculation and how do
they work - ANSWER ATP and NA.
Initially, there is an increase in seen in contraction caused by P2X activation by ATP.
There is then a second contraction caused by NA activation of the alpha receptor
What happens if the P2X receptor is knocked out - ANSWER There is dribbled
ejaculation and therefore infertility
semen comes out but as a dribble and this is insufficient in inducing insemination (don't
get good squeeze - this is because the nerve cannot adequately secrete ATP/NA due to
degeneration)
What neurotransmitter is released to allow for an erection - ANSWER NO
Describe characteristics of NO - ANSWER Lipid soluble, not stored in vesicles therefore
synthesized on demand, readily passes across membranes, allows for SM relaxation,
readily destroyed
How is NO synthesized and released - ANSWER Increase in Ca2+ (with CaM kinase)
activates NOS - gets L-arginine to donate of its NO and it results in NO + L-cit - NO very
, lipid soluble so flies out of neuron into smooth muscle - NO acts on guanylyl cyclase-
cGMP produced (2nd mess) Activates PKG -causes phosphorylation + closes calcium
channel + blocks contraction from happening
What enzyme breaks down cGMP - ANSWER Phosphodiesterase
What happens if your nerves don't work too well due to a) diabetes, b) accident induced
nerve damage. - ANSWER diabetes: viagra works by INHIBITING PDE which means that
PDE CAN NO LONGER STOP THE ERECTION AND BREAK DOWN cGMP - cGMP active
for longer - longer erection due to vasodilatory effects
accident: Viagra will not be of any help because you cannot produce the NO in the first
place so do not produce cGMP/PKG cascade
Mechanism of action of viagra/sildenafil - ANSWER Inhibits the action of
phosphodiesterase, therefore increasingterm-12 vasodilation
What 4 parts of the male reproductive tract is required for ejaculation - ANSWER Vas
deferens, prostate, seminal vesicles, and the urethra
What is retrograde ejaculation? - ANSWER Sperm made in testis - goes via vas deferens
through seminal vesicles (semen) - semen travel through ejaculatory duct however, this
duct has intermediate connection with bladder (sphincter present at bottom of bladder
and contracts during ejaculation to prevent urine entrance - contracts using NA)
- Goes into bladder accidentally
What causes penile relaxation after erection - ANSWER Sympathetic innervation from
NA
What occurs in diabetes? - ANSWER - Diabetes results in decreased nerve function
- nerve function in males is imperative to reproduction and ejaculation - means that NO
cannot be used to induce erection
Describe detumescence. - ANSWER relaxation of penis post-erection
Parasympathetic (erection) - PDE gets NO dilator out of the way
Sympathetic, afterwards return to normal - NA added to blood system to induce
constriction
What are the key players in sensory vasodilation in the female? - ANSWER Sensory
nerve endings:
1. Peptides - calcitonin gene-related peptide (CGRP)
2. Activate AC/cAMP system
3. SP Dilator
With Complete Solutions
Reduced fertility - trauma and disease - ANSWER
What are the four key plays in reproductive function? - ANSWER Nerves, hormones,
smooth muscle, secretory tissue
Are nerves important in female reproductive function? - ANSWER Not as much as in
males.
What basal requirements regarding second messengers are necessary for relaxation of
smooth muscle? - ANSWER In order for relaxation to occur we need to get rid of
calcium. Work through cAMP and cGMP and induce activation of PKA and PKG
What can PKG/PKA do generally in the relaxation of smooth muscle/prevention of
contraction? - ANSWER 1. send calcium away into storage
2. kick calcium out
3. induce hyperpolarisation
What can PKA phosphorylate to aid in smooth muscle relaxation? - ANSWER 1. Plasma
membrane calcium pumps
2. ER Ca2+ pumps
3. MLCK
4. K+ channels
How does cAMP/PKA evoke SM relaxation? - ANSWER Hormone binds to the receptor
causing G protein dissociation = activation of adenylate cyclase, = increase in PKA =
phosphorylates K channel = hyper polarisation = Ca2+ channel close = no calcium
entering = relaxation.
How does calcium ellicit a contraction? - ANSWER Calcium binds to calmodulin =
activates the myosin light chain kinase (MCLK) = myosin/actin overlap = contraction
PKA/PKG can prevent a contraction from happening. How does this occur? - ANSWER
PKA can phosphorylate MLCK. This prevent it from binding to the CA2+/CaM complex
and inducing a contraction.
This is what occurs in erection.
What are the sympathetic neurotransmitters? - ANSWER NA, ATP
,What is the parasympathetic neurotransmitter for relaxation? - ANSWER NO
What are the sensory transmitter? - ANSWER NPY, CGRP (both important for female
lubrication; CGRP important in ERECTION)
Describe NA and Ach synthesis. - ANSWER NA synthesized in the vesicles and second
last product of NA put into vesicles and final synthesis occurs within vesicle and so this
requires ATP
Acetylcholine for parasympathetic synthesized in the cell body and then final product is
put into the vesicles
What types of receptors are found in smooth muscles? - ANSWER - junctional receptors
(RACs: these are fast acting receptors - occur only in vas deferens)
- alpha-AR extra-junctional receptors (7 mem-spanning - GPCR - usually have
noradrenaline as ligand, allow a small number of neurotransmitter to induce large effect
to give good contraction through signal transduction)
- P2X receptors - ATP receptors adapted for ATP activity
Which receptor does ATP act on? - ANSWER P2X
What is speed of ejaculation dependent upon? - ANSWER Strength of smooth muscle
contraction (ATP2PTX INTERACTION).
Describe neuroeffector transmission. - ANSWER Nerves come in to smooth muscle -
vesicles containing noradrenaline release the NA, ATP and ACH onto smooth muscles
What are the two innervators for vas deferen contraction for ejaculation and how do
they work - ANSWER ATP and NA.
Initially, there is an increase in seen in contraction caused by P2X activation by ATP.
There is then a second contraction caused by NA activation of the alpha receptor
What happens if the P2X receptor is knocked out - ANSWER There is dribbled
ejaculation and therefore infertility
semen comes out but as a dribble and this is insufficient in inducing insemination (don't
get good squeeze - this is because the nerve cannot adequately secrete ATP/NA due to
degeneration)
What neurotransmitter is released to allow for an erection - ANSWER NO
Describe characteristics of NO - ANSWER Lipid soluble, not stored in vesicles therefore
synthesized on demand, readily passes across membranes, allows for SM relaxation,
readily destroyed
How is NO synthesized and released - ANSWER Increase in Ca2+ (with CaM kinase)
activates NOS - gets L-arginine to donate of its NO and it results in NO + L-cit - NO very
, lipid soluble so flies out of neuron into smooth muscle - NO acts on guanylyl cyclase-
cGMP produced (2nd mess) Activates PKG -causes phosphorylation + closes calcium
channel + blocks contraction from happening
What enzyme breaks down cGMP - ANSWER Phosphodiesterase
What happens if your nerves don't work too well due to a) diabetes, b) accident induced
nerve damage. - ANSWER diabetes: viagra works by INHIBITING PDE which means that
PDE CAN NO LONGER STOP THE ERECTION AND BREAK DOWN cGMP - cGMP active
for longer - longer erection due to vasodilatory effects
accident: Viagra will not be of any help because you cannot produce the NO in the first
place so do not produce cGMP/PKG cascade
Mechanism of action of viagra/sildenafil - ANSWER Inhibits the action of
phosphodiesterase, therefore increasingterm-12 vasodilation
What 4 parts of the male reproductive tract is required for ejaculation - ANSWER Vas
deferens, prostate, seminal vesicles, and the urethra
What is retrograde ejaculation? - ANSWER Sperm made in testis - goes via vas deferens
through seminal vesicles (semen) - semen travel through ejaculatory duct however, this
duct has intermediate connection with bladder (sphincter present at bottom of bladder
and contracts during ejaculation to prevent urine entrance - contracts using NA)
- Goes into bladder accidentally
What causes penile relaxation after erection - ANSWER Sympathetic innervation from
NA
What occurs in diabetes? - ANSWER - Diabetes results in decreased nerve function
- nerve function in males is imperative to reproduction and ejaculation - means that NO
cannot be used to induce erection
Describe detumescence. - ANSWER relaxation of penis post-erection
Parasympathetic (erection) - PDE gets NO dilator out of the way
Sympathetic, afterwards return to normal - NA added to blood system to induce
constriction
What are the key players in sensory vasodilation in the female? - ANSWER Sensory
nerve endings:
1. Peptides - calcitonin gene-related peptide (CGRP)
2. Activate AC/cAMP system
3. SP Dilator
