5.1 Reflexes Flashcards Preview

A Level Biology > 5.1 Reflexes > Flashcards

Flashcards in 5.1 Reflexes Deck (21):
1

what is a reflex?

involuntary response to sensory stimulus

2

state the steps in a reflex arc:

stimulus
receptor
sensory
relay
motor
effector
response

3

what is a withdrawal reflex?

one that involves moving away e.g. hand moving away from a hot object

4

what is the blinking reflex?

the involuntary blinking of the eyelids

5

when does the corneal reflex occur?

when the cornea is stimulated (touched)

6

when does the optical reflex occur?

when the eye is exposed to bright light

7

why is the blinking reflex known as the CRANIAL REFLEX?

occurs in the brain and not the spinal cord

8

1. when the cornea is stimulated the stimulus triggers....

...an impulse along a sensory neurone (fifth cranial nerve)

9

2. the impulse then passes....

....through a relay neurone in the lower brain stem

10

3. impulses are then sent...

...along branches of the motor neurone (seventh cranial nerve)

11

4. this initiates....

.... a motor response that closes the eyelids

12

5. the closing of both the eyelids is called a...

....consensual response

13

when examining unconscious patients why do doctors test for the blinking reflex?

used to determine if the patient is brain dead
reflex is present it indicates lower brain stem is functioning

14

what type of reflex is the knee jerk reflex?

spinal reflex

15

1. the patella is tapped this....

...stretches the patella tendon

16

2. stimulus initiated reflex arc causes the extensor muscle on top of the thigh ....

... to contract

17

3. a relay neurone inhibits the (?) of the flexor muscle causing....

...it to relax
(?) motor neurone

18

4. contraction coordinated with relaxation of antagonistic flexor hamstring muscle....

....causes the leg to kick

19

what could the absence of the knee jerk reflex indicate?

nervous problems

20

what do reflexes prevent or reduce?

the body being harmed / severity of damage

21

reflexes are extremely fast and prevent what?

the brain being overloaded increasing chances of survival

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