Reflexes

Question 1

Define a reflex

Answer 1

Rapid automatic response to a change in internal or external environment.

Question 2

Characteristics of neurons

Answer 2

By a stimulus.

Involuntary: Without conscience thought. Rapid: Only a few neurons involved. Stereotyped: Occurs in same way each time.

Question 3

Spinal reflexes

Answer 3

• Carried out by spinal cord only.
• Eventually impulses may be sent to brain, so it is aware of what is occurring.
• Person would only become consciously aware of situation, after response has been made.

Question 4

Reflex arc

Answer 4

Purpose is to protect the body from dangerous situations. 1. A receptor in end of a sensory neuron detects a change in environment and reacts to this stimulus by producing a nerve impulse.

2. Sensory neuron carries impulse to spinal cord.
3. Information is processed in CNS (S.C). Nerve impulse is passed across a synapse either straight to a motor neuron or via 1 or more interneurons to motor neuron.
4. Motor neuron carries nerve impulse to an effector.
5. Effector (muscle or gland) receives nerve Impulse and carries out an appropriate response.

Question 5

Protective reflexes

Answer 5

Protect body from injury.

E.g. Blinking, Sneezing, Coughing, Constriction of pupils.

Question 6

Learned/acquired reflexes

Answer 6

Complex motor patterns appear during a baby’s development. Other reflexes are learned through constant repetition.

Question 7

Label a spinal reflex arc

Answer 7