Nervous system
Sensory receptors
The eye the ear and others
● Receptors are stimulated by an external stimuli and a intern stimulate
● Sensory neurons which send messages to the brain for interpretation
● Receptors are grouped according to the kinds of stimulus they receive
Types of receptors
- Photoreceptor: responds to the visible wavelength of light
- Mechanoreceptor: sensitive to the mechanical energy
- Thermal receptor: sensitive to heat and cold
- Osmo receptor: detects changes in the concentration of solutes in the body's fluids
- chemoreceptor sensitive to specific chemicals such as concentration of oxygen in the
blood
- Nocireceptor: a pain receptor that is sensitive to tissue damage
Sensory adapt
- when a receptor becomes accustomed to the stimulus and ceases to fire even though
the stimulus is still present
- for example: after you put your clothing on you are no longer conscious of the fact that
they are still touching your skin
, The eye
The eyeball
- the eyeball consists of three layers of tissue surrounding a jelly-like fluid
- the three layers: the sclera the choroid and the retina
- the jelly-like fluid on the inside of the eyeball is called the vitreous humor the vitreous
humor is important because it helps maintain the shape of the eyeball
Sclera, choroid, retina:
- Sclera is a tough protective layer that surrounds the eyeball. the front of the sclera is
transparent and is called the cornea
- Choroid: located just inside the sclera. This layer contains blood vessels that nourish the
eye. towards the front of the eye, the chloride forms forms the iris and the ciliary muscles
which can control the shape of the lens
- Retina: the innermost layer. this layer contains special photoreceptive cells called rods
and cones which transmit visual information to the brain via the optic nerve
Sensory receptors
The eye the ear and others
● Receptors are stimulated by an external stimuli and a intern stimulate
● Sensory neurons which send messages to the brain for interpretation
● Receptors are grouped according to the kinds of stimulus they receive
Types of receptors
- Photoreceptor: responds to the visible wavelength of light
- Mechanoreceptor: sensitive to the mechanical energy
- Thermal receptor: sensitive to heat and cold
- Osmo receptor: detects changes in the concentration of solutes in the body's fluids
- chemoreceptor sensitive to specific chemicals such as concentration of oxygen in the
blood
- Nocireceptor: a pain receptor that is sensitive to tissue damage
Sensory adapt
- when a receptor becomes accustomed to the stimulus and ceases to fire even though
the stimulus is still present
- for example: after you put your clothing on you are no longer conscious of the fact that
they are still touching your skin
, The eye
The eyeball
- the eyeball consists of three layers of tissue surrounding a jelly-like fluid
- the three layers: the sclera the choroid and the retina
- the jelly-like fluid on the inside of the eyeball is called the vitreous humor the vitreous
humor is important because it helps maintain the shape of the eyeball
Sclera, choroid, retina:
- Sclera is a tough protective layer that surrounds the eyeball. the front of the sclera is
transparent and is called the cornea
- Choroid: located just inside the sclera. This layer contains blood vessels that nourish the
eye. towards the front of the eye, the chloride forms forms the iris and the ciliary muscles
which can control the shape of the lens
- Retina: the innermost layer. this layer contains special photoreceptive cells called rods
and cones which transmit visual information to the brain via the optic nerve
