14 Coordination and Response
(Core / Extended)

14.1 Coordination and Response
What you need to know:

1. State that electrical impulses travel along neurones
2. 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
3. Describe the role of the nervous system as coordination and regulation of body functions
4. Identify in diagrams and images sensory, relay and motor neurones
5. Describe a simple reflex arc in terms of: receptor, sensory neurone, relay neurone, motor neurone and effector
6. Describe a reflex action as a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)
7. Describe a synapse as a junction between two neurones
8. Describe the structure of a synapse, including the presence of vesicles containing neurotransmitter molecules, the synaptic gap and receptor proteins
9. 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
10. State that synapses ensure that impulses travel in one direction only 

Videos: Nervous System

Videos: Nervous System and Reflex Arc

Videos: Synapses

Videos: Nerve Cells, neurons & Synapses

14.2 Sense Organs
What you need to know:

1. Describe sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals
2. Identify in diagrams and images the structures of the eye, limited to: cornea, iris, pupil, lens, retina, optic nerve and blind spot
3. 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 on to the retina (d) retina – contains light receptors, some sensitive to light of different colours (e) optic nerve – carries impulses to the brain
4. Explain the pupil reflex, limited to changes in light intensity and pupil diameter
5. Explain the pupil reflex in terms of the antagonistic action of circular and radial muscles in the iris
6. Explain accommodation to view near and distant objects in terms of the contraction and relaxation of the ciliary muscles, tension in the suspensory ligaments, shape of the lens and refraction of light
7. Describe the distribution of rods and cones in the retina of a human
8. 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 colours, for colour vision
9. Identify in diagrams and images the position of the fovea and state its function 

Videos: Human Eye - Structure of Eye and Iris Reflex

Videos: Human Eye - Accommodation

Videos: Detailed structure of the eye

14.3 Hormones
What you need to know:

1. 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
2. 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
3. State that glucagon is secreted by the pancreas
4. 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
5. Describe the role of adrenaline in the control of metabolic activity, limited to: (a) increasing the blood glucose concentration (b) increasing heart rate
6. Compare nervous and hormonal control, limited to speed of action and duration of effect ​
   

Videos: The Endocrine System

Videos: Blood Vessels section 9.3.5 & 9.3.6

14.4 Homeostasis
What you need to know:

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

Videos: Homeostasis

Videos: Type 1 and Type 2 Diabetes

Videos: Hormones and Homeostasis

14.5 Tropic Responses
What you need to know:

1. Describe gravitropism as a response in which parts of a plant grow towards or away from gravity
2. Explain phototropism and gravitropism of a shoot as examples of the chemical control of plant growth
   
3. Describe phototropism as a response in which parts of a plant grow towards or away from the direction of the light source
   
4. 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
   
5. Investigate and describe gravitropism and phototropism in shoots and roots​
   

Videos: Tropic Responses

EXAMPLE QUESTIONS

Videos: Mixed Questions - Coordination and Response (Nervous System)

Videos: Mixed questions