Course Description:

Welcome to our Biology Cambridge IGCSE course, meticulously tailored to help you conquer the intricacies of Topic 14: Coordination and Response. This comprehensive course is specifically designed for both Code 0610 and Code 0970 syllabi, ensuring you’re well-prepared for the IGCSE Biology examination.

Course Highlights:

• Comprehensive Core and Supplement Objectives: Master all core and supplement objectives as outlined in the syllabus for theory (papers 1, 2, 3, 4). These objectives provide a solid foundation for exam success.
• Thoroughly Explained Experiments: Gain a deep understanding of practical experiments with detailed explanations. Notes summarize the method, results, interpretation, evaluation, reliability, and conclusion, enabling you to excel in paper 6 questions.

Course Outline & Objectives (Core and Supplement):

1. Coordination and Response (Lesson 1): Key objectives include:

• State that electrical impulses travel along neurones.
• Describe the mammalian nervous system in terms of (a) the central nervous system (CNS) consisting of the brain and the spinal cord (b) the peripheral nervous system (PNS) consisting of the nerves outside of the brain and spinal cord!
• Describe the role of the nervous system as the coordination and regulation of body functions.
• Identify in diagrams and images sensory, relay and motor neurones.
• Describe a simple reflex arc in terms of receptor, sensory neurone, relay neurone, motor neurone, and effector.
• Describe a reflex action as a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)
• Describe a synapse as a junction between two neurones.
• Describe the structure of a synapse, including the presence of vesicles containing neurotransmitter molecules, the synaptic gap and receptor proteins.
• Describe the events at a synapse as (a) an impulse stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap (b) the neurotransmitter molecules diffuse across the gap (c) neurotransmitter molecules bind with receptor proteins on the next neurone (d) an impulse is then stimulated in the next neurone.
• State that synapses ensure that impulses travel in one direction only.

2. Sense Organs (Lesson 2): Key objectives include:

• Describe sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature, and chemicals.
• Identify in diagrams and images the structures of the eye, limited to cornea, iris, pupil, lens, retina, optic nerve, and blind spot.
• Describe the function of each part of the eye, limited to (a) cornea – refracts light (b) iris – controls how much light enters the pupil (c) lens – focuses light onto the retina (d) retina – contains light receptors, some sensitive to light of different colors (e) optic nerve – carries impulses to the brain.
• Explain the pupil reflex, limited to changes in light intensity and pupil diameter.
• Explain the pupil reflex in terms of the antagonistic action of circular and radial muscles in the iris.
• Explain accommodation to view near and distant objects in terms of the contraction and relaxation of the ciliary muscles, the tension in the suspensory ligaments, the shape of the lens, and the refraction of light.
• Describe the distribution of rods and cones in the retina of a human.
• Outline the function of rods and cones, limited to (a) greater sensitivity of rods for night vision (b) three different kinds of cones, absorbing light of different colors, for color vision.
• Identify in diagrams and images the position of the fovea and state its function.

3. Hormones (Lesson 3): Key objectives include:

• Describe a hormone as a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs.
• Identify in diagrams and images specific endocrine glands and state the hormones they secrete, limited to (a) adrenal glands and adrenaline (b) pancreas and insulin (c) testes and testosterone (d) ovaries and oestrogen.
• Describe adrenaline as the hormone secreted in ‘fight or flight’ situations and its effects, limited to (a) increased breathing rate (b) increased heart rate (c) increased pupil diameter.
• Compare nervous and hormonal control, limited to speed of action and duration of effect.
• State that glucagon is secreted by the pancreas.
• Describe the role of adrenaline in the control of metabolic activity, limited to: (a) increasing the blood glucose concentration and (b) increasing heart rate.

4. Homeostasis (Lesson 4): Key objectives include:

• Describe homeostasis as the maintenance of a constant internal environment.
• State that insulin decreases blood glucose concentration.
• Explain the concept of homeostatic control by negative feedback with reference to a set point.
• Describe the control of blood glucose concentration by the liver and the roles of insulin and glucagon.
• Outline the treatment of Type 1 diabetes.
• Identify in diagrams and images of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory neurones, blood vessels, and fatty tissue.
• Describe the maintenance of a constant internal body temperature in mammals in terms of insulation, sweating, shivering, and the role of the brain.
• Describe the maintenance of a constant internal body temperature in mammals in terms of vasodilation and vasoconstriction of arterioles supplying skin surface capillaries.

5. Tropic Responses (Lesson 5): Key objectives include:

• Describe gravitropism as a response in which parts of a plant grow towards or away from gravity.
• Describe phototropism as a response in which parts of a plant grow towards or away from the direction of the light source.
• Explain the phototropism and gravitropism of a shoot as examples of the chemical control of plant growth.
• Explain the role of auxin in controlling shoot growth, limited to: (a) auxin is made in the shoot tip (b) auxin diffuses through the plant from the shoot tip (c) auxin is unequally distributed in response to light and gravity (d) auxin stimulates cell elongation.

6. Experiment – Gravitropism in Pea Radicles (Lesson 6): Key objectives include:

• To illustrate gravitropism in the roots of pea radicles.

7. Experiment – Phototropism in Shoots (Lesson 7): Key objectives include:

• To illustrate phototropism in germinating seeds.