2j-Co-ordination and response Flashcards
Q: What is coordination and why is it important?
A: Coordination allows organisms to detect and respond to changes in their environment, ensuring survival and homeostasis.
Q: How do plants and animals respond to stimuli?A:
Plants: Respond through hormones like auxins that control growth (e.g., phototropism and geotropism).
Animals: Use the nervous system and endocrine system to respond rapidly and precisely.
Q: What is the nervous system and how does it work?
A: The nervous system transmits electrical impulses along neurons to coordinate responses. It includes:
Central Nervous System (CNS): Brain and spinal cord.
Peripheral Nervous System: Nerves that connect the CNS to the body.
What are the three types of neurons and their roles?
Sensory Neurons: Transmit impulses from receptors to the CNS.
Relay Neurons: Transmit impulses within the CNS.
Motor Neurons: Transmit impulses from the CNS to effectors (muscles or glands).
What is a reflex arc?
A reflex arc is an automatic response to a stimulus that protects the body from harm. It follows this pathway: Stimulus → Receptor → Sensory Neuron → Relay Neuron → Motor Neuron → Effector → Response.
How does the endocrine system coordinate responses?
A: The endocrine system uses hormones (chemical messengers) released into the bloodstream, such as:
Adrenaline: Increases heart rate and prepares the body for “fight or flight.”
Insulin: Lowers blood glucose levels.
Testosterone, Oestrogen, and Progesterone: Control reproductive processes.
Q: How does the eye respond to light intensity?
A: The eye regulates light entry through the pupil reflex:
Bright Light: Circular muscles contract, constricting the pupil.
Dim Light: Radial muscles contract, dilating the pupil.
Q: How does the body maintain internal temperature?
A: Thermoregulation is controlled by the hypothalamus:
When too hot: Sweating, vasodilation, and reduced shivering.
When too cold: Shivering, vasoconstriction, and reduced sweating.
Practical: Investigating Reaction Time
Investigating the Effect of Caffeine on Reaction Time:
Method: Use the ruler drop test to measure reaction time before and after caffeine consumption.
Positive Result: Shorter reaction time indicates improved nervous system response.
Negative Result: No significant change suggests no effect.
Practical: Investigating Reaction Time
Investigating Plant Responses to Light (Phototropism):
Investigating Plant Responses to Light (Phototropism):
Method: Grow seedlings with light from one side and observe growth.
Positive Result: Seedlings bend toward the light, indicating phototropism.
Negative Result: Seedlings grow straight if no directional light is present.
