action potential and efferents

What is the point of action potentials?

To trigger synaptic transmission:

1. Ligand/mechanically gated open for graded potential

2. Depolarized Graded potential is suprathreshold at axon hillock and triggers action potential

3. Repeated sequence

Stop transmission by hyperpolarizing graded potential so no action potential is sent

Action potential begins two ways

1. Suprathrehold at axon hillock for first Action potential

2. Local current for middle of axon

Simple neural reflex

Cerebrum

Cortex: thoughts and senses

Basal nuclei

Limibic system: emotions

Hypothalamus

Posterior pituitary: volume/osmolarity homeostasis

Anterior pituitary

Brain stem

Midbrain

Pons and medulla: cardiovascular and respiratory control

Baroreceptor = medulla

Chemoreceptor for respiration: pons and medulla

Parasympathetic

Rest and digest

Stimulus and afferent to brain?, efferent far from spinal cord,preganglionic neuron releases Ach which is received by Nicotonic receptors on postganglionic and that releases Ach to muscorinic receptors in organs

Sympathetic

Fight or flight

Stimulus sent to thoracic or Lumbar, preganglionic neuron close to spinal cord and release Ach to nicotine receptor on postganglionic neuron which releases norepinephrine adrenergic receptor in organs

Somatic

Stimulus to every part of spinal cord, preganglionic neuron releases Ach to nicotine receptor on skeletal muscle

Ventral/front to dorsal/back

Ventral horn: somatic motor neuron

Lateral horn: autonomic

Dorsal horn: afferent/sensory