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LBB 3 Mens Bodies.ppt
LBB_3_Mens_Bodies.ppt
Showing 68-81 out of 148
LBB 3 Mens Bodies.ppt-Men’s Bodies LeVay, Baldwin ...
LBB_3_Mens_Bodies.ppt-Men’s Bodies LeVay, Baldwin & Baldwin,
LBB 3 Mens Bodies.ppt-Men’s Bodies ...
LBB_3_Mens_Bodies.ppt-Men’s Bodies LeVay, Baldwin & Baldwin,
Page 68
Enlarged prostate
Page 69
The Testicles Produce Sperm and Sex Hormones
The bulbourethral glands secrete a clear,
alkaline, mucous fluid, which often begins
to flow during sexual arousal.
During coitus, the alkaline bulbourethral and
prostatic secretions may help neutralize the
acidic environments in the urethra and
vagina, thus increasing viability of the
sperm.
Page 70
The Nervous System
Orchestrates Sexual Arousal &
Response
Erections can be mediated by spinal reflexes
and the balance of activity in the sympathetic
and parasympathetic nervous systems.
The penis and clitoris possess a unique class
of sensory nerve endings called genital end-
bulbs.
Pudendal nerves convey sensory information
from, and motor output to, the penis and
clitoris. Acetylcholine is the transmitter to the
muscles.
Pelvic nerves carry autonomic output to the
penis and clitoris.
Page 71
The Nervous System Orchestrates Sexual Arousal
•
Spinal reflexes include:
1.
Nerves to detect stimulation
2.
Nerves to convey sensory information to the
spinal cord
3.
A processing center in the spinal cord
4.
Nerves that carry an output signal to the penis or
clitoris
5.
Vascular elements necessary for erection
Page 72
The Nervous System (Part
1)
Page 73
The Nervous System (Part
2)
Page 74
The Nervous System (Part
3)
Page 75
The Nervous System (Part
4)
Page 76
The Nervous System (Part
5)
Page 77
Sensory innervation of the
penis
The penis and clitoris
have sensory nerve
endings: genital end-
bulbs, often bunched
together.
Greatest density in
corona of glans and
frenulum.
However, penis &
clitoris lack fine touch
sensitivity in fingertips:
specialized for erotic
Page 78
Erections
Erectile tissue of the corpora cavernosa forms
a hydraulic system.
Erections result from a decrease in
sympathetic, and an increase in
parasympathetic, nervous system activity.
Erections are also influenced by striated
muscles that innervate the penis.
Brain areas such as the hypothalampus
(especially the medial preoptic area, MPOA),
pons, and medulla are important for mediating
erections.
Page 79
Figure 2.11
The Autonomic Nervous System
Page 80
Figure 4.10
Nerve pathways involved in erection