Nerves and Sensory Receptors

___→ Afferent → ___

Sensory, Dorsal

___→ Efferent → ___

Gray matters consists of:

Neuron cell bodies

White matter consists of:

Myelinated axons

What are the 3 columns of white matter?

• Ventral

• Dorsal

• Lateral

How do dorsal root and ventral root differ?

Dorsal root has ganglia

Reflexes are:

Homeostatic

Patellar Stretch Reflex

• No Interneuron

• Knee Jerk Reflex

  • Contract quads

Golgi Tendon Reflex

• Inhibitory Interneuron

  • Inhibits hamstrings from flexing to take tension off tendons

Withdrawal Reflex

• Excitatory interneuron

  • Excites hamstring flexors to pull foot back

Withdrawal Reflex w/ Reciprocal Innervation

• Inhibitory interneuron

  • Inhibits front extensors on affected leg

Withdrawal Reflex w/ Crossed Extensor Reflex

• Excitatory interneuron

  • Excites front extensor on unaffected leg for stability

Tonic Receptors

• Accommodate slowly

• Merkel

• Ruffini

Phasic Receptors

• Sensitive

• Accommodate quickly

• Pacinian

• Meissner

• Pain

Chemoreceptors

• Detect changes in blood concentration of glucose, oxygen, and hydrogen

• Become attached to receptors on their membrane

Mechanoreceptors

• Compression, bending, stretching of cells

• Touch, pressure, proprioception, balance

Thermoreceptors

Respond to changes in temperature

Photoreceptors

Respond to light

Nociceptors

Extreme mechanical, chemical, or thermal stimuli

Primary receptors

Conduct APs in response to a receptor potential

Secondary receptors

Release neurotransmitters in response to a receptor potential

Working memory

• Briefly stored to perform a task

• Long-term potentiation

  • Frequent activation increase synaptic connections

Short-term memory

• Info stored for minutes to days

• Consolidation

  • Short-term memories stabilized into long-term memories

Long-term memory

• Declarative

  • Retention of facts

• Procedural

  • Development of skills