nervous system and the eye Flashcards
mem
endocrine control
involves hormones as chemical signals
hormones transported by blood
usually slow responses
responses can be short lived or long lived
always involuntary
may affect more than one target organ
nervous control
involves nerves impulses as signals
nerve impulses are carried by neurons
usually quick responses
short lived responses
can be either voluntary or involuntary
usually have a localised effect
central nervous system
brain and spinal cord
cns
peripheral nervous system
cranial nerves from brain
spinal nerves from the spinal cord
sensory receptors (sense organs)
reflex arc
def and 6 parts
shortest pathway by which nerve impulses travel from the receptr to the effector in a reflex action
stimulus
receptors
sensory neurone
relay neurone
motor neurone
effector
voluntary actions path
path:
brain, relay neurone in spinal cord, motor neurone, effector
spinal reflex
def and eg
controlled by spinal cord
eg. knee jerk
cranial reflexes
def and eg
controlled by brain (but not consciously)
eg. pupil reflex, blink, salivation
reflect arc example
heat stimulate pain receptor
nerve impulses produced, travel along sensory neurone to spinal cord
nerve impulses transmitted first via neurotransmitters across a synapse to the relay neurone and then across another synapse to the motor neurone
at the same time, nerve impulses are transmitted to the brain
motor impulses leave spinal cord along the motor neurone to the effector
muscle contracts causes withdrawal
What is the primary function of the cornea?
The primary function of the cornea is to refract light entering the eye.
True or False: The lens of the eye changes shape to help focus light on the retina.
True
Fill in the blank: The _______ is the colored part of the eye that regulates the size of the pupil.
iris
What are the two types of photoreceptors in the retina?
Rods and cones.
What is the role of rods in vision?
Rods are responsible for vision in low light conditions.
What is the function of cones in the retina?
Cones are responsible for color vision and visual acuity in bright light.
True or False: The fovea is the area of the retina with the highest concentration of rods.
False
What is the pupil reflex?
The pupil reflex is the automatic adjustment of the pupil size in response to light intensity.
Multiple Choice: Which structure is responsible for the majority of light refraction in the eye? A) Lens B) Cornea C) Retina D) Iris
B) Cornea
What defect is characterized by difficulty seeing objects at a distance?
Myopia (nearsightedness).
What defect is characterized by difficulty seeing objects up close?
Hyperopia (farsightedness).
What is astigmatism?
Astigmatism is a refractive error caused by an irregular shape of the cornea or lens.
Fill in the blank: The _______ is the transparent structure behind the iris that helps focus light onto the retina.
lens
True or False: The retina is responsible for converting light into neural signals.
True
What is the blind spot of the eye?
The blind spot is the area on the retina where the optic nerve exits and contains no photoreceptors.
