B6.1

Question 1

living organisms can detect and respond to what?

Answer 1

a stimulus

Question 2

what is a stimulus?

Answer 2

a change in the environment of an organism such as light, temperature etc

Question 3

what are receptors stimulated by?

Answer 3

the stimulus

Question 4

what is a simple reflex

Answer 4

a rapid automatic response

Question 5

what do the simplest animals rely on for the majority of their behaviour?

Answer 5

reflex actions

Question 6

what do the reflex actions ensure for the animals?

Answer 6

that the animal will respond in a way that is most likely to result in its survive (finding food, sheltering from predators)

Question 7

newborn babies:

stepping reflex-

Answer 7

when held under its arms in an upright position with its feet on a firm surface, a baby makes walking movements with its legs

Question 8

newborn babies:

grasping reflex

Answer 8

a baby tightly grasps a finger that is out in its hand

Question 9

newborn babies:

startle reflex

Answer 9

a baby shorts out its arms and legs when startled (sudden loud noise)

Question 10

adult:

pupil reflex

Answer 10

bright light causes muscles in the eye to contract so that the retina is not damaged

Question 11

adult:

knee-jerk reflex

Answer 11

when the knee is strict just below the knee cap, the leg will kick out

Question 12

adult:

dropping hot object reflex

Answer 12

when picking up a very hot object, the response is to throw it away to prevent damage to the hand

Question 13

what does nervous co-ordination in an animal require?

step 1 of 3

Answer 13

the presence of one or more different receptors to detect stimuli (e.g light detected by eyes)

Question 14

nervous co ordination in an animal

2

Answer 14

processing centres to receive information and co ordinate responses

Question 15

nervous coordination in an animal

3

Answer 15

effectors to produce the response

Question 16

what are the two ways of sending signals in the body?

Answer 16

• via electrical impulses through long, wire-like cells called neurons (nerve cells)
• via chemicals called hormones that are produced in the glands and travel in the blood

Question 17

way of sending signals in the body:

electrical impulses

Answer 17

• sensory= receptors–> CNS

* Motor=CNS–> effectors

Question 18

what do electrical impulses target?

Answer 18

effectors

Question 19

chemical signals are ______ than electrical impulses

Answer 19

slower

Question 20

where do chemical signals move to?

how long do their effects last?

Answer 20

target organs

a long time

Question 21

example of chemical signal

Answer 21

insulin which controls blood sugar levels

Question 22

what did the development of nervous and hormonal communication systems depended on?

Answer 22

the evolution of multicellular organisms

Question 23

what do receptors produce?

Answer 23

a rapid, involuntary response called a simple reflex