coordination and response

Question 1

the three main parts to a coordinated response are

Answer 1

1. a stimulus eg temp change
2. a receptor to detect the change
3. an effector to carry out the response

Question 2

what does auxin trigger

Answer 2

the growth of the main stem of the plant

Question 3

how does auxin causes the shoots to grow towards the light source

Answer 3

• auxin collects on the shaded side
• auxin promotes cell growth
• the shoot curves toward the light

Question 4

what’s the difference between nervous and hormonal communication

Answer 4

• nervous uses nerve cells and impulses but hormones are secreted by glands and travel in the blood
• nervous communication is generally much faster than hormonal communication
• hormonal communication usually brings about longer lasting responses than nervous communication

Question 5

the difference between central and peripheral nervous system

Answer 5

the central nervous system is the brain and spinal cord. the peripheral nervous system is every other part of the nervous system

Question 6

how is an impulse transmitted between two neurons

Answer 6

• the impulse reaches the end of one neuron
• a neurotransmitter is released and it diffuses across the gap
• a new impulse is triggered in the next neuron

Question 7

what does a sensory neuron do

Answer 7

connects a receptor to the CNS

Question 8

what is an effector

Answer 8

a part of the body that brings about the response to a stimulus like a muscle or a gland

Question 9

what does the motor do

Answer 9

connects the CNS to an effector

Question 10

where does the lens focus light on

Answer 10

the retina

Question 11

what is the retina and what does it do

Answer 11

its the back part of the eye and it converts visual stimuli into electrical impulses

Question 12

what happens when the eye focuses on near objects

Answer 12

• ciliary muscles contract and suspensory ligaments relax causing the lens to thicken
• thicker lens causes the light to refract more

Question 13

what happens when the eye focuses on far objects

Answer 13

• ciliary muscles relax and suspensory ligament stretch which makes the lens thinner
• thinner lens causes the light to refract less

Question 14

what is vasodilation

Answer 14

• the body detects a rise in temperature
• blood vessels supplying the capillaries at the skin surface dilate
• more blood flows closer to the skin where it can cool

Question 15

what is vasoconstriction

Answer 15

• the body detects a drop in temperature
• blood vessels supplying the capillaries at the skin surface constrict
• less blood flows closer to the skin surface so less heat is lost to the surroundings

Question 16

what are hormones

Answer 16

chemical messengers that are secreted by glands of the endocrine system into the bloodstream

Question 17

what are three effects of adrenaline in the body

Answer 17

• increases heart and breathing rate
• increases blood glucose concentration
• dilates the pupils

Question 18

what does FSH stimulate

Answer 18

stimulates the follicle to mature and release oestrogen

Question 19

what does a surge in LH cause

Answer 19

the release of an egg from a follicle (ovulation)

Question 20

where are FSH and LH secreted from

Answer 20

the anterior pituitary gland

Question 21

where is ADH secreted from

Answer 21

the posterior pituitary gland