1. Reflexes Rapid, predictable, involuntary response to stimuli
Maintain homeostasis
Autonomic reflexes include smooth and cardiac muscle and glands
Somatic reflexes include skeletal muscle

2. Reflex Arc Receptor (ex. In skin to detect pain, cold, heat, pressure)
Sensory Neuron
Interneuron (spinal cord)
Motor neuron
Effector (skeletal muscle, smooth muscle, glands, heart)

3. Stretch Reflexes Prevent overstretching of muscle
Important for posture
Equipment: Reflex hammer
Patellar reflex assesses spinal cord L2 to L4
Achilles reflex assesses first two sacral segments

4. Superficial Cord Reflexes
Stimulated by receptors in the skin
Depend on upper motor pathways and cord level reflexes

5. Plantar Reflex Babinski
Equipment: Reflex Hammer Handle
Normal response: toes curl
Positive Babinski: toes flare
Normal Babinski response in infant indicates damage area between spinal cord and brain.

6. Cranial Nerve Reflexes
Pupillary Reflexes
Equipment: flashlight
A reflex in which light shone into one eye causes the pupils of BOTH eyes to constrict involuntarily protecting against damage to the retina

7. Pupillary Reflex cont’d
Absence of normal reflex, indicates:
Severe trauma
Deterioration of vital brain tissue due to metabolic imbalance
Death!

8. Human Reflexes
Biology 12