Psych Unit 2 - Biological Bases of Behavior

• The Endocrine System


  Body's slow chemical communication system; a set of glands that secrete hormones into the bloodstream
• Hormones


  Chemical messengers that are secreted by endocrine glands; affect mood, arousal, and more
• Pituitary Gland

  Located in the forebrain structure below the hypothalamus. Regulates growth, breast milk production, childbirth, and bonding, and communicates to other glands to release hormones. It secretes various hormones that stimulate other glands
• Pineal Gland

  Located in the forebrain structure. Regulates seasonal and sleep cycles and melatonin levels
• Adrenal Gland

  Located above the kidney. Is controlled by the sympathetic nervous system's flight-or-fight reaction, which increases heart rate, blood pressure, and glucose levels to respond to a threat. Secretes Cortisol Epinephrine, and Norepinephrine
• Gonads

  The sex glands, the testes and ovaries. Allow for sexual reproduction and secrete Androgens, including testosterone, Estrogen, and Progesterone
• Central nervous system

  Located in the brain and spinal cord and is the body's master control unit. It creates automatic response to a stimulus, very simple pathway, reflexes
• Peripheral nervous system


  Located outside of the brain and spinal cord and focuses on sensory and motor neurons
• Somatic nervous system


  Part of the Peripheral nervous system that carries sensory information and relays motor commands to muscles; controls voluntary movements
• Autonomic nervous system


  Part of the Peripheral nervous system that controls the glands and other muscles; controls involuntary movements
• Sympathetic nervous system


  Part of the Autonomic nervous system that controls the "fight or flight" responses by arousing the body, mobilizing its energy in stressful situations
• Parasympathetic nervous system


  Part of the Autonomic nervous system calms the body and control relaxing responses (rest and digest)
• Sensory/Afferent Neurons

  Takes information received through sensory receptors throughout the body and passes it on toward the brain and spinal cord to initiate a response (think hand being squeezed)
• Motor/Efferent Neurons

  Transmit signals from the brain to our muscles and other organs; information exiting the brain (think squeezing the next person's hand)
• Interneurons

  Relay neurons, or connectors, allowing for information to pass between neurons
• Receptor Sites


  Small knobs located at the end of the dendrites on the postsynaptic neuron that receive neurotransmitters as they cross the synapse to initiate cell firing
• Dendrites


  Branches extending from the cell body that receive chemical messages via neurotransmitters from other neurons and transports them to the cell body of the neuron
• Soma (Cell Body)


  The center of the neuron which contains the nucleus and produces energy for the neuron
• Axon


  A long tube-like extension attached to the cell body that sends electrical messages (action potential) away from the cell body
• Myelin Sheath


  A layer of fat cells surrounding the axon of some neurons that provides insulation and increases the speed of the electrical messages (action potential)
• Terminal Buttons


  Small knobs at the end of the axon that contain neurotransmitters in vesicles (sacs) to be released across the synapse
• Vesicles


  Tiny sacs located in the terminal buttons that store and release neurotransmitters
• Synapse/Synaptic Gap

  A small space between the sending neuron and the receiving neuron which is the location for neurotransmission; no physical contact between neurons
• Glial Cells

  Provide physical and chemical support to neurons
• Action Potential (Depolarization)


  Travels the length of the axon and causes release of neurotransmitter into the synapse
• Repolarization


  Return the ions to their original positions on the inside and outside of the axon
• Resting Potential(Polarization)


  While the neuron is waiting for a message, the fluid-filled interior of the axon has a negative charge and the fluid exterior has a positive charge
• Refractory Periods


  While repolarization is occurring, the neuron cannot fire because it is resetting itself to its original resting potential state
• All-or-none Law


  Once threshold has been reached, the neuron fires completely, regardless of how strong the stimulus was
• Threshold


  When the neuron is stimulated by pressure, heat, light, or chemical messages, the electrical charge inside the axon can reach a tipping point
• Reuptake


  Neurotransmitters are absorbed by the neuron that releases them; they are recycled and reused
• Agonist


  Drugs that work by either blocking reuptake or mimicking the effects of neurotransmitters by fitting into receptor sites on the postsynaptic neuron (ex. opiates are agonists as they mimic the effects of endorphins)
• Antagonist


  Drugs that work by blocking receptor sites on the postsynaptic neuron and block the impact of neurotransmitters (ex. botulinum causes paralysis because it blocks the release acetylcholine, an important neurotransmitter in muscle action)
• Excitatory


  Chemicals released from terminal buttons increasing the chances that neurons will fire off an action potential
• Inhibitory


  Chemicals released from terminal buttons decreasing the chance it will jump into action potential
• Acetylcholine


  Excitatory neurotransmitter that enables muscle action, memory, and movement. Malfunctions with Alzeihmers
• Serotonin


  Excitatory and Inhibitory that affects mood, hunger, sleep and arousal. Undersupply is linked to depression
• Dopamine


  Excitatory that influences movement, learning, attention, and emotion. Too much is linked to schizophrenia. Too little linked to Parkinson's disease
• Norepinephrine


  Excitatory and Inhibitory that helps control alertness and arousal. Undersupply can depress mood
• Endorphins


  Inhibitory neurotransmitter linked to pain control and pleasure.