Physio Labs

Question 1

the ability to determine fine detail and distinguish one object from another

Answer 1

Visual acuity

Question 2

Snellen test

E charts

Answer 2

several rows of letters

only the letter E in different positions

Question 3

some letters

disappear while you are looking at other letters. You may have

Answer 3

visual field problem

Question 4

Having 20/20 vision means that

Answer 4

your visual acuity at 20 feet away from an object is normal

Question 5

Refractive errors, such as nearsightedness or farsightedness, occur when light rays entering the eye can’t focus exactly

Answer 5

on the nerve layer (retina

Question 6

refraction

Answer 6

When light passes from one substance to another of different density its speed changes and the rays are bent.

Question 7

The bending power of the cornea and vitreous humor are

Answer 7

constant

Question 8

but the lens’s refractive strength varies when it

Answer 8

Changes shape

Question 9

In general, light from a distant source (over 20 feet) approaches the eyes as parallel rays so

Answer 9

change in lens shape is necessary for it to focus properly on the retina.
Retina needs to be flat

Question 10

The lens is flat because the ciliary muscle is ….. and the tension of the suspensory ligament attached to the lens is ……, so light refraction is …..

Answer 10

relaxed

increased

decreased

Question 11

The ability of the eye to focus for close objects (less than 20 feet) is called

Answer 11

accommodation

Question 12

To focus on near objects, the lens becomes … because the ciliary muscle ….. and the tension of the suspensory ligament is ….., so light refraction is ….

Answer 12

round
contracts
decreased
increased

Question 13

The elasticity of the lens decreases dramatically with age, resulting in difficulty in focusing for near or close vision. This is called

Answer 13

presbyopia

Question 14

Lens elasticity can be tested by measuring the

Answer 14

near point accommodation

Question 15

In young adults, the near point of accommodation is about

Answer 15

10 cm from the eye.

Closer in children and further in old people

Question 16

The eye that focuses images correctly on the retina is said to have

Answer 16

emmetropia.

Question 17

the image focuses in front of the retina

Answer 17

myopia

Question 18

the image focuses behind the retina

Answer 18

hyperopia

Question 19

Irregularities in the curvature of the lens and/or the cornea lead to a blurred vision problem called

Answer 19

astigmatism

Question 20

In astigmatism blurry images occur because

Answer 20

points of light are focused on the retina as lines rather than individual points

Question 21

The intrinsic muscles,

controlled by the autonomic nervous system, are

Answer 21

ciliary body

Iris

Question 22

ciliary body function

Answer 22

which changes the shape of the lens

Question 23

Iris function

Answer 23

which controls the pupil size and regulates the amount of light rays entering the eye

Question 24

The extrinsic muscles, controlled by the somatic nervous system, are

Answer 24

the rectus and oblique muscles,

Question 25

the rectus and oblique muscles, functions

Answer 25

control eyeball movement and make it possible to keep moving objects focused on the fovea centralis (for central vision) convergence, or medial eye movement, which is essential to keep both eyes aimed at a close object for near vision.

Question 26

Pupils that dilate in response to bright light, or are sluggish to close, are abnormal and may indicate

Answer 26

a neurological disorder (such as autism, Alzheimer’s disease, etc.), or it may indicate drunkenness

Question 27

Accomodation reflex involve

Answer 27

triad of changes when a person looks at a nearby object

Question 28

accommodation reflex is | mediated by

Answer 28

both of the intrinsic eye muscles. The lens becomes rounder so that the divergent light rays will be refracted to focus on the fovea centralis during near vision, and the iris constricts to reduce divergent light rays from entering the eye for a sharper image. The convergence reflex is mediated by the extrinsic eye muscles. Medial movement of the eyeball keeps the pupil aligned with the object as it moves closer.

Question 29

Pathway of accommodation

Answer 29

1. Afferent impulses from retina pass along the normal visual pathway to reach the visual areas in the occipital lobe 2. From the visual areas fibers descend to the oculomotor (3rd cranial nerve) nucleus of both side in the midbrain. 3. Efferent fibers pass along the 3 rd cranial nerve to the eye to supply the following muscles: Medial rectus muscle Constrictor pupillae muscle Ciliaris muscle

Question 30

In accommodation reflex the fibers reach the lateral geniculate body and the occipital cortex but they donot pass through

Answer 30

the pretectal nucleus situated in midbrain.

Question 31

Direct pupillary reflex checks health of

Answer 31

Optic and occulomotor nerve of the same eye

Question 32

InDirect pupillary reflex checks health of

Answer 32

Occulomotor nerve of the same eye and optic nerve of the other eye.

Question 33

The basis of distinguishing colors is based on the presence of

Answer 33

3 separate photopigments sensitive to different wavelengths of light in different cones.

Question 34

3 separate photopigments are most sensitive to

Answer 34

Blue Green Red Respectively

Question 35

The perception of colors of different hues is mediated by

Answer 35

varying degrees of excitation of cones bearing different photopigments.

Question 36

The blue sensitive photopigment is encoded in the .... chromosome of the human genome, and the green and red sensitive photopigment is encoded in the genes on ...... Color blindness is mostly a .... disorder

Answer 36

7th the X chromosome genetic

Question 37

Protanopia

Answer 37

red color blindness,

Question 38

Deuteranopia

Answer 38

green color blindness

Question 39

tritanopia

Answer 39

blue color blindness.

Question 40

the Ishihara test,

Answer 40

Color blind test

Question 41

reflex is made possible by

Answer 41

neural pathways called reflex arcs which can act on an impulse before that impulse reaches the brain.

Question 42

automatic response to a stimulus that does not receive or need conscious thought.

Answer 42

Reflex

Question 43

the operation of reflexes.

Answer 43

1. Receptor detects the internal or external change. 2. Sensory neuron transmits nerve impulses from the receptor into the brain or spinal cord. 3. Interneuron serves as processing center, conducts nerve impulses from the sensory neuron to a motor neuron. 4. Motor neuron: conducts motor output fron the brain or spinal cord to the periphery. 5. Effecter can be a muscle or gland. It responses to stimulation by the motor neuron and produces the reflex or behavioral action.

Question 44

Wires attached to head by salty base that conducts electricity

Answer 44

Electrodes

Question 45

Wave amplitude is measured by... and indicates....

Answer 45

Microvolts | How much electricity is going beneath the electrodes

Question 46

EEG paterns are due to

Answer 46

Postsynaptic Graded potential

Question 47

A high amplitude (يعني من فوق لتحت) indicates

Answer 47

Many neurons activated | Synchronous

Question 48

A low amplitude

Answer 48

Neurons are less activated | Asynchronous

Question 49

Amplitude range

Answer 49

0.5-100 microvolt

Question 50

Wave frequency indicates and is measured by

Answer 50

Hertz | How often the wave cycles from max to min amplitude

Question 51

Range of frequency

Answer 51

1-40 hz

Question 52

Low frequency indicates while high frequency indicates

Answer 52

Less responsive states | High alerts

Question 53

Distinct levels of frequency

Answer 53

Beta (14-30) Hz Alpha (8-13) Hz Theta (4-7) Hz Delta (lower than 3.5)

Question 54

Patterns are abnormal over

Answer 54

Diseased or damaged areas

Question 55

A shift from a low amplitude to a high one means

Answer 55

Epileptic seizure

Question 56

High amplitude in epilepsy reaches

Answer 56

1000 mv

Question 57

Epilepsy can cause

Answer 57

Seizure Loss of consciousness Changes in behaviour

Question 58

2 ways of transmission of sound waves

Answer 58

Air (ossicle) | Bone construction

Question 59

A normal ear hears better in

Answer 59

2X better in ossicle ratger tham bone

Question 60

Our own voice is transferred via

Answer 60

Both air and bone

Question 61

Steps of air transmission

Answer 61

Waves in air vibrate fluid in cochlea which moves trympanic memebrane, middle ear ossicle and oval window

Question 62

In normal hearing weber is R rinne L rinne

Answer 62

Centralized in middle + +

Question 63

If right ear is conducive hearing loss then

Answer 63

Weber: right centralized Right Rinne : negative Left rinne: positive

Question 64

If a right ear has sensory neural loss then

Answer 64

Weber: left centralized Right rinne: pathological positive Left rinne: positive

Question 65

an involuntary and nearly instantaneous movement in response to a stimulus

Answer 65

Reflex

Question 66

neural pathways which can act on an impulse before that impulse reaches the brain.

Answer 66

called reflex arcs

Question 67

Lesions that damage the sensory or motor limb of a reflex arc will

Answer 67

diminish that reflex.

Question 68

the net result of lesions that damage the descending tracts is facilitation of reflexes that are mediated

Answer 68

at only the level of the spinal cord

Question 69

After acute lesions, spinal reflexes often pass through an initial stage of hypoactivity. This stage has been called

Answer 69

spinal shock" or diaschisis

Question 70

When reflexes return after spinal transection, they become

Answer 70

extremely hyperactive.

Question 71

a simple reflex, with the receptor neuron having direct connections to the muscle spindle apparatus in the muscle and with the alpha motor neurons in the central nervous system that send axons back to that muscle

Answer 71

myotatic) reflex i

Question 72

the ability to discern between two points touching the skin.

Answer 72

Two-point discrimination

Question 73

Two factors determine two-point discrimination:

Answer 73

density of sensory receptors, and size of neuronal receptive fields.

Question 74

Fingertips have..... more density of sensory receptors than the hand.

Answer 74

3-4 times

Question 75

specific sensory space that if simulated will result in the activation of that particular neurone.

Answer 75

receptive field of that neurone.

Question 76

areas with the most sensitive two-point discrimination should have

Answer 76

high density of receptors with small receptive fields.