Biological Basis of Behavior So our brain chemistry and make-up is responsible for our behavior?

The Nervous System I. The Neuron -structural and functional unit of the nervous system

Three Parts of the Neuron Dendrite, Cell body, Axon

The Parts of the Neuron 1. Dendrites - receive incoming messages to the nerve cell - resemble tree branches 2. Cell Body - contains nucleus

Axon -- conducts impulses away from the nerve cell to other neurons - Myelin sheath - fatty material that covers the axon and insulates it which increases conduction speed - Nodes of ranvier -spaces between the myelin sheath where information can become depolarized ( get lost)

Terminal Buttons (end bulb) - holds chemicals which communicate with other neurons by firing information across the synapse to the next cell body, organ or muscle

Synapse - a very small space in between the end bulb and it’s adjacent cell, organ or muscle

a. Transmitters - a chemical messenger between cells/neurons Examples of neurotransmitters- seratonin, GABA, dopamine

- excitatory - chemical locks open and neurons are turned on - inhibitory - chemical locks are closed and neurons turn off

Seratonin is the brain chemical that is associated with moods, concentration and attention Thinking about the information in the last slides, explain what happens in the brain with people who are depressed

b. Receptors - special areas on the dendrite that function like a chemical lock

Types of Neurons a.Sensory or Afferent neurons - transmit messages from sensory receptors to the brain and spine

a.Inter neurons - located entirely within the brain and spinal cord, intervene between sensory and motor neurons

C.Motor or Efferent Neurons - transmit impulses from sensory or inter neurons to muscle cells that contract or gland cells that secrete (sends messages away from the brain) Examples- reflexes

Babinski reflex

Using information learned in class, explain what happens when you touch a hot stove

Somatic Nervous system Controls voluntary activities Such as…

Autonomic Nervous system Controls involuntary responses such as heart rate

Sympathetic Nervous system Sympathetic - prepares the body for strenuous activity - ex- speeds heart rate

Parasympathetic - works to conserve energy in the body and return it to its normal state

Somatic Nervous system part of the nervous system that controls voluntary activitiesPart of the Nervopus system that controls voluntary