Reflexes & Receptors

A rapid, automatic response to change in external or internal environment which is one way a body achieves homeostasis

• Stimulus - Is required to trigger off a reflex, not spontaneous • Involuntary - occurs without any conscious thought • Rapid - only a small number of neurons • Stereotyped - It occurs in the same way each time it happens

• Name given to pathway of a nerve impulse from receptor to the effector muscle • Coordinated by the spinal cord • Rapid and Involuntary • Protect the body from injury

• Receptor in the skin/sensory organ detects a stimulus • Nerve impulse travels along sensory neuron to the spinal cord in the dorsal root via the dorsal root ganglion • Synapse occurs where the neurotransmitter present at the axon terminal diffuse across the synapse (gap) and attaches itself to the receptors on the dendrite on the inter neuron • Electrical impulses continues along inter neuron • Synapse takes place • Message is sent to the brain (CNS) to make it aware of what is happening • Nerve impulse continues along the motor neuron towards the effector at the neuromuscular junction causing the effector to contract and produce a response

A structure that is able to detect change in the body’s internal or external environment