Brown Fat
Compared to white fat, brown fat cells have many more mitochondria and fat
vacuoles.
Has abundant sympathetic innervation as well as blood supply located in the neck,
intrascapular area, mediastinum, surrounds spinal cord and kidneys.
Functions to elevate core body temperature.
Thermal Neutral Zone
First proposed by Cross & Hill in 1959.
Defined as range of ambient temperatures at which
Metabolic rate is at a minimum
Temperature regulation is achieved by control of sensible (non-evaporative) heat
loss
Modes of Heat Loss
Conduction – transfer of heat energy from the body to a solid object and/or surface
in direct contact with the body (e.g. heat loss from neonate to a weighing scale)
Convection – transfer of thermal energy from the body to an adjacent gas (air).
Heated gas (heat coming off of body) expands and is displaced upwards by
cooler surrounding gas (Boyle’s law).
Contributes of convective heat loss
Position of body (flexed or extended)
Body surface area