Page 3 - Prueba

1 Skin and touch

Receptors are the variety of sensors that allow the nervous system to detect
different stimuli. A stimulus is any sign that passes information to the
nervous system; it can be either external or internal. We can classify
receptors according to the type of stimuli they receive, and their location.

STIMULI THEY RECEIVE LOCATION
Receptor Stimuli
Interoceptors are internal
Physical changes: pressure, receptors that detect changes
Mechanoreceptors
sound, touch, gravity inside the body, including
blood pressure, hunger and
oxygen levels in the brain, and
Photoreceptors Light body temperature.

Chemoreceptors Chemical changes Exteroceptors are external
receptors found on the outer
surface of the body that
Thermoreceptors Temperature changes allow for vision, smell, taste,
balance, hearing and touch.

Pain receptors Pain

Skin and touch

The skin is a large, thin organ that has sensory receptors for touch. It has
the following elements:
Epidermis. Outer
layer, made up of
layers of cells which
are always dividing. Sebaceous gland
They form scale-like
structures. Eventually,
the cells at the top fall
off and new cells Hair follicle
replace them.

Dermis. Middle layer,
made up of connective
Subcutaneous layer. tissue. There are hair
Inner layer, made up of follicles, sebaceous
connective fibres and glands, sweat glands and
adipose tissue. It gives blood vessels in it.
the skin flexibility,
stores fat and acts as a
thermal insulator. It
also has nerves and
blood vessels. Adipose cells Blood vessels
Sweat gland
62 UNIT 6