Co-ordination And Response
Overview
Your body is constantly responding to changes both inside and outside it. When you step on something sharp, your foot lifts before you even feel pain. When your blood sugar rises after a meal, hormones bring it back down. Even a plant bending toward a window is co-ordinating a response. All of these examples depend on detecting a stimulus and producing an appropriate response.
In this lesson you will explore how the nervous and hormonal systems work, how the eye and reflex arcs function, how plants respond to light and gravity, and how the body maintains a stable internal environment through homeostasis. This is one of the broadest topics in the Edexcel specification and appears regularly on both papers.
Objectives
- Understand how organisms are able to respond to changes in their environment
- Understand that homeostasis is the maintenance of a constant internal environment, and that body water content and body temperature are both examples of homeostasis
- 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, resulting in rapid responses
- Understand the role of neurotransmitters at synapses
- Describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
- 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
- Understand the sources, roles and effects of the following hormones: ADH, FSH and LH
Mind map
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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.
- In a reflex arc, which neurone connects the sensory neurone to the motor neurone? A) Effector neurone B) Relay neurone C) Receptor neurone D) Connector neurone Answer: B
- Which hormone lowers blood glucose levels? A) Glucagon B) Adrenaline C) Insulin D) ADH Answer: C
- When looking at a near object, the ciliary muscles: A) Relax, making the lens thin B) Contract, making the lens fat C) Relax, making the lens fat D) Contract, making the lens thin Answer: B
- What is the role of auxin in phototropism? A) It kills cells on the lit side B) It accumulates on the shaded side, causing those cells to elongate more C) It accumulates on the lit side, causing those cells to elongate more D) It prevents growth on both sides Answer: B
- Vasodilation helps the body to: A) Conserve heat B) Lose heat C) Absorb more oxygen D) Digest food faster Answer: B
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