Co-ordination And Response
Overview
Your pupils shrink when you step into bright sunlight. A seedling curves toward a window. Your hand jerks away from a hot surface before you even feel the pain. All of these are coordinated responses, where a stimulus is detected, a signal is sent, and an effector carries out a precise action.
This topic explores how organisms detect and respond to changes in their environment through nervous and hormonal systems. You will learn about homeostasis, plant tropisms and auxin, the structure and function of the nervous system and the eye, reflex arcs, temperature regulation by the skin, and the roles of five key hormones.
Objectives
- Understand how organisms are able to respond to changes in their environment
- Understand that homeostasis is the maintenance of a constant internal environment
- Understand that a co-ordinated response requires a stimulus, a receptor and an effector
- Understand that plants respond to stimuli
- Describe the geotropic and phototropic responses of roots and stems
- Understand the role of auxin in the phototropic response of stems
- Describe how nervous and hormonal communication control responses and understand the differences between the two systems
- Understand that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves
- Understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system
- Understand the role of neurotransmitters at synapses
- Describe the structure and functioning of a simple reflex arc
- Describe the structure and function of the eye as a receptor
- Understand the function of the eye in focusing on near and distant objects and in responding to changes in light intensity
- Describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation
- Understand the sources, roles and effects of the following hormones: adrenaline, insulin, testosterone, progesterone and oestrogen
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Flashcards
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Co-ordination And Response. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- What is homeostasis? A) The ability to move in response to a stimulus B) The maintenance of a constant internal environment C) The process of growth and development D) The removal of waste products Answer: B
- In a reflex arc, which type of neurone carries impulses from the receptor to the CNS? A) Motor neurone B) Relay neurone C) Sensory neurone D) Connector neurone Answer: C
- Auxin promotes cell elongation in shoots. What happens when light comes from one side? A) Auxin moves to the lit side, causing bending away from light B) Auxin moves to the shaded side, causing bending toward light C) Auxin is destroyed by light D) Auxin has no effect on the direction of growth Answer: B
- Which hormone is produced by the pancreas and lowers blood glucose? A) Adrenaline B) Testosterone C) Insulin D) Oestrogen Answer: C
- When focusing on a near object, the ciliary muscles: A) Relax, making the lens thinner B) Contract, making the lens thicker C) Relax, making the lens thicker D) Contract, making the lens thinner Answer: B
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