Reflexes & Receptors

Question 1

What is a reflex?

Answer 1

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

Question 2

What are the properties of a Reflex?

Answer 2

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

Question 3

What is a reflex arc or spinal reflex?

Answer 3

• 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

Question 4

What are the components of a Reflex Arc?

Answer 4

1. Receptor in the skin/sensory organ detects a stimulus
2. Nerve impulse travels along sensory neuron to the spinal cord in the dorsal root via the dorsal root ganglion
3. 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
4. Electrical impulses continues along inter neuron
5. Synapse takes place
6. Message is sent to the brain (CNS) to make it aware of what is happening
7. Nerve impulse continues along the motor neuron towards the effector at the neuromuscular junction causing the effector to contract and produce a response

Question 5

What is a receptor?

Answer 5

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