The document summarizes various mechanisms that regulate heat in the scrotum to maintain the optimal temperature for sperm production. It discusses (1) the tunica dartos smooth muscle and cremaster muscle that relax or contract to control proximity to the body, (2) the counter-current mechanism where the testicular artery exchanges heat with returning veins to deliver cooler blood to the testes, and (3) a lack of fat layer and abundance of sweat glands that enhance heat loss and keep temperatures lower than the core body. These combined mechanisms precisely regulate scrotal temperature for spermatogenesis.

1. Counter Current Heat
Mechanism

2. Heat regulation in scrotum
a) Tunica Dartos smooth muscle
b) Cremaster muscle
c) Counter current heat mechanism
d) The absence of subcutaneous fat layer
e) A abundance of sweat glands

3. Tunica Dartos
• Dartos muscles relaxes when ambient or core
temperature increases
• It get relaxed by cooling the testes by holding it
away from the body
• Improving the blood flow
• Facilitating heat loss of skin
• During the cooler environment it holds the
testes closer to body and contracts the muscles

4. Cremaster muscles
• It is the skeletal muscle fiber in spermatic cord
• Its controls the distance of testes held in body
• Contraction causes the elevation of testes
• Relaxation causes the descension of the testes
Dartos control the scrotal skin
Cremaster raises and lowers the testis

5. Counter – current system
• The pampiniform plexus is a vascular structure
consisting of an intimately tangled artery and vein
and this structure is important for proper temperature
control of the testis and it is wrapped around the
spermatic cord
• Testicular artery that takes blood to the testes from
abdominal aorta descents from the pampiniform
plexus of veins the return blood from testes.
• Heat exchange b/w the artery and the veins via this
arrangement also help in scrotal temperature

6. • Because of the counter current the testes
receives cooler blood compared to other part of
the body
• Blood returning from the testis has lost heat to
the environment and this it is cooler than artery
blood.
• When the artery blood enters the pampiniform
tissue it loses its heat to the cooler blood and
cooled blood travel around the testis and veins
• This mechanism is effective only it loses its heat
by the radiation, convection and evaporation to
the environment

9. • The absence of subcutaneous fat layer
It acts as a insulator and protect from
conduction of heat loss to the environment by the
body
• A abundance of sweat glands
Mechanism of sweating on the scrotal
skin helps in maintain the testicular temperature
below the body core

10. Thank
you