1. Today: Response and feedback loops: setpoints
Speed and specificity of control systems
Patterns of control pathways
The organization of the nervous system
Neurons
Midterm test:
Monday Oct. 7: 8:30 – 9:20
multiple choice questions
Location: A- P in the Education Gym
Q-Z in Erie Hall (lecture hall)

3. Setpoints can vary
Acclimatization – adaptation to a given set of environmental conditions (first day of spring like weather)
Acclimation – adaptation to laboratory setting

4. Endocrine and Nervous Reflexes
Specificity of target cells
Nature of signal
Speed
Duration of action
Stimulus intensity coding

5. Specificity of target cells
A neuron has a specific target cell. Many tissues may have receptor proteins for
a hormone and may respond to the hormone.

6. Nature of signal
In neurons,
electrical signals travel
long distances and
chemical signals (neurotransmitters)
move to the target cell.

7. Nature of signal
The endocrine system uses chemical signals.

8. Electrical signals travel long distances and
Nature of signal: Neuroendocrine:
Electrical signals travel long distances and
chemical signals (neurohormones) move into blood vessels.

9. Speed Electrical signals conducted very quickly
Rapid signal transduction with many neurotransmitters
Hormones move by diffusion from endocrine cell to target (slower)
Some responses take quite a long time

10. Duration of action Nervous control is shorter than endocrine control
Nervous – usually neurotransmitter is rapidly removed

11. Stimulus intensity coding
Intensity is coded by neuronal firing frequency amount of neurotransmitter
The amount hormone that is released codes the intensity.

12. Knee jerk reflex
Lactation, oxytocin
Autonomic stimulation
of insulin release
Growth hormone

13. Testosterone
Low glucose
and beta cells

14. Organization of the nervous system
Sensory Receptors  afferent pathway  central nervous system (CNS, brain and spinal cord  efferent neurons (peripheral nervous system PNS) target
PNS:
Somatic motor division
Autonomic division:
Sympathetic
Parasympathetic

15. Cells of the nervous system:
-neuron