IGCSE Biology Notes – Control & Regulation
1. Human Coordination (2.80, 2.82-
2.92)
2. Hormones & Homeostasis (2.81,
2.93, 2.94, 2.95)
3. Excretion (2.71-2.79)
, 1. Human Coordination
2.80 Receptors detect stimuli, and Effectors produce a response
2.82 A response requires a stimulus, a receptor, and an effector.
2.87 The nervous system consists of:
Brain
Spinal cord
Receptors - in sense organs
Effectors - muscles or glands
The brain and spinal cord are called the Central nervous system (CNS).
The Peripheral nervous system is nerves, which connect the CNS.
Nerves consist of nucleus, cytoplasm and cell membrane.
The three types of nerves (motor, relay and sensory) all look different:
2.88
A reflex arc is created when a receptor in a sense organ is stimulated and sends
electrical impulses through the CNS to an effector.
2.89 Synapse - the junction between neurons.
Electrical impulses cannot travel across this gap, so instead they release
chemicals called neurotransmitters.
These diffuse across the synapse and continue the impulse on the next neuron.
2.90 A simple reflex arc goes stimulus-->receptor-->sensory neuron-->relay
neuron-->motor neuron-->effector-->response.
The brain is not apart of this arc, because it would take too long and your body
wants to protect you.
2.91 Features of the Eye
1. Human Coordination (2.80, 2.82-
2.92)
2. Hormones & Homeostasis (2.81,
2.93, 2.94, 2.95)
3. Excretion (2.71-2.79)
, 1. Human Coordination
2.80 Receptors detect stimuli, and Effectors produce a response
2.82 A response requires a stimulus, a receptor, and an effector.
2.87 The nervous system consists of:
Brain
Spinal cord
Receptors - in sense organs
Effectors - muscles or glands
The brain and spinal cord are called the Central nervous system (CNS).
The Peripheral nervous system is nerves, which connect the CNS.
Nerves consist of nucleus, cytoplasm and cell membrane.
The three types of nerves (motor, relay and sensory) all look different:
2.88
A reflex arc is created when a receptor in a sense organ is stimulated and sends
electrical impulses through the CNS to an effector.
2.89 Synapse - the junction between neurons.
Electrical impulses cannot travel across this gap, so instead they release
chemicals called neurotransmitters.
These diffuse across the synapse and continue the impulse on the next neuron.
2.90 A simple reflex arc goes stimulus-->receptor-->sensory neuron-->relay
neuron-->motor neuron-->effector-->response.
The brain is not apart of this arc, because it would take too long and your body
wants to protect you.
2.91 Features of the Eye
