Nervous System: Reflexes and Sensory System

What is a reflex?

unconscious response to a stimulus

5 parts of a reflex:

receptor, afferent pathway, integrating center, efferent pathway, and effector

What is a simple reflex?

a monosynaptic reflex, one neuron

What does a complex reflex involve?

2 neurons

Name the spinal reflexes

Capillary Refill

What are the stretch reflexes?

Patellar and Achilles

How does a stretch reflex work?

tapping on ligament or tendon causing muscle fibers to stretch, stimulating afferent neuron to transmit info to the spinal cord to an efferent neuron that then stimulates contraction of the effector muscle

Why would you clasp your hands in front of you when doing a stretch reflex?

to distract your brain

What happens with constricted pupils?

parasympathetic, contract muscle

What happens with dilated pupils?

sympathetic, relaxed muscle

What helps the eyes focus on a stationary target when a person rotates?

sensations from the semicircular canals of the labyrinth of the inner ear

The pattern of the eye movement, slowly in one direction, then rapidly in the opposite direction, is called what?

nystagmus

What is endolymph?

fluid found in the membranous labyrinth of the inner ear

In what kind of people can you observe nystagmus?

seasick/carsick or people who are under the influence

What is conduction deafness?

damage to the middle ear, air wave sound

What is sensorineural deafness?

damage to the auditory nerve of the inner ear

What time should be faster for sound conduction?

air conduction

What time should be longer for sound conduction?

bone conduction

What does the Weber test determine?

if both ears are equal in sensitivity

What is caused by an uneven curvature of the cornea or lens?

Astigmatism

What is Astigmatism?

Where the focus of an image on the retina may be blurred in some regions

What is visual acuity?

The ability to see an image clearly, the object is focused precisely on the retina

What is the ability of the eye to keep an image in clear focus on the retina as an object moves closer or farther away from the eye?

Accommodation

What is the near point of accommodation?

The minimum distance a person can see an object in focus

When does Accommodation occur?

when the lens changes shape to bend light waves

Far Vision

relax ciliary zonules, lens becomes flat, sympathetic

Close vision

contact ciliary zonules, lens become more round, parasympathetic

What contains the visual receptor cells, rods and cones?

retina

What is the optic disc?

a round structure in the retina that has no rods or cones

What is an optic disc referred to as?

the blind spot

What is color blindness caused by?

a defect in the light-sensing pigments of cones

Why is color blindness more common in males than in females?

genes for color vision are located on the X chromosome

What is the percentage of males who lack green and red color vision?

8%

What is the field of vision?

a measurement of the range, in degrees, of vision when focusing straight ahead

What is the reading field?

a measurement of the range, in degrees, that letters can be read when focusing straight ahead

What can high-density areas distinguish?

if stimulus is caused by 2 separate stimuli or just one

Areas of the body that are highly sensitive to touch have what kind of density and receptive fields?

High density with small receptive fields