Biological Basis of Behavior

So our brain chemistry and make-up is responsible for our

behavior?

The Nervous SystemI. 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 Neuronsa. 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 activitiesSuch as…

Autonomic Nervous system• Controls involuntary responses

such as heart rate

Sympathetic Nervous systemSympathetic- 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