3.4.1 Control Systems Involve Stimulus and Response Flashcards Preview

A-level Biology Oxford AQA > 3.4.1 Control Systems Involve Stimulus and Response > Flashcards

Flashcards in 3.4.1 Control Systems Involve Stimulus and Response Deck (28)
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1

What do receptors do?

Detect stimuli

2

What can receptors be?

Cells or proteins on cell surface membranes

3

What are effectors?

Cells that bring about a response to stimulus to produce an effect

4

Give examples of types of effectors cells

Muscle cells and cells found in glands e.g. pancreas

5

How do receptors communicate with effectors?

Via nervous system and/or hormonal system

6

Name 3 types of neurones 

  1. Sensory neurones 
  2. Motor neurones 
  3. Intermediate/relay neurones 

7

What do sensory neurones do?

Transmit electrical impulses from receptors to the CNS - the brain and spinal cord

8

What do motor neurones do?

Transmit electrical impulses from CNS to effectors

9

What do relay neurones do?

Transmit electrical impulses between sensory neurones and motor neurones

10

State the 5 stages of a response to a stimulus

11

What the central nervous system (CNS) made up of?

Brain and spinal cord

12

What is the peripheral nervous system (PNS) made up of?

Neurones that connect the CNS to the rest of the body

13

What does the somatic nervous system control?

Conscious activities e.g running and playing video games

14

What does the autonomic nervous system control?

Controls unconscious activities e.g. digestion

15

What does the sympathetic nervous system do?

Gets the body ready for action - 'flight or fight' system

16

What does the parasympathetic nervous system do?

Calms the body down - 'rest and digest' system

17

What is a reflex?

When body responds to stimulus without making a conscious decision to respond

18

What is a reflex arc?

Pathway of neurones linking receptors to effectors in a reflex

19

Describe the simple reflex arc for a hand-withdrawal response to heat

  1. Thermoreceptors in skin detect heat stimulus
  2. Sensory neurone carries impulses to relay neurone
  3. Relay neurone connects to motor neurone
  4. Motor neurone sends impulses to effector
  5. Muscle contracts to withdraw your hand and stop it being damaged

20

What does it mean if there's a relay neurone involved in a simple reflex arc?

It's possible to override the reflex

e.g. your brain could tell your hand to withstand the heat

21

Explain how nervous communication is localised 

When electrical impulse reaches end of neurone = neurotransmitters are secreted directly onto target cells

22

Explain how nervous communication is short-lived 

Neurotransmitters are quickly removed once they've done their job

23

State the 2 types of responses that simple mobile organisms have to keep them in a favourable environment

  • Tactic (taxes)
  • Kinetic (kineses)

24

Define taxes

Organisms move towards or away from a directional stimulus e.g. light 

25

Define kineses

Organisms' movement is affected by non-directional stimulus e.g. humidity

26

Give an example of taxes

  • e.g. woodlice show tactic response to light (phototaxis)
  • Move away from light source
  • Helps them to survive ∵ it keeps them concealed under stones during the day (where they're safe from predators) & keeps them in damp conditions (reduces water loss)

27

Give an example of kineses

  • e.g. woodlice show kinetic response to humidity
  • High humidity = move slowly and turn less often = so they stay where they are
  • Air gets drier = move faster and turn more often = move into new area
  • Response increases chance woodlouse will move to area with higher humidity
  • Improves survival chances of organisms = reduces their water loss & keeps them concealed 

28

Explain the importance of relfex actions (3)

  • Automatic / involuntary
  • Prevents injury 
  • Role in homeostasis 

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