2. Nervous System: Biological Control Center Brain – thinks, calculates, feels, and controls motivation Spinal cord Bundle of long nerves running through spine Connects brain to every part of body Biological foundations of Behavior

3. Neurons: The Units of the Nervous System Neuron – individual nerve cell Parts of neurons Cell body: central part of nerve cell; contains nucleus or cell’s control center Dendrites: small branches extending from cell; receive messages from other neurons Axons: small branches at other end of neuron; send messages to other neurons Biological foundations of Behavior

4. Neurons: The Units of the Nervous System

5. Neural Transmission Neurons Function like wires and batteries Have sacs filled with fluid chemicals containing surrounded by a second type of chemical Ions: positive or negative changed particles Cell membrane semipermeable in normal resting state Polarized when negative ions inside cell membrane and positive ions outside Biological foundations of Behavior

6. Neural Transmission Neurons Depolarization – positive ions enter membrane All-or-none principle Action potential Myelin sheath Average thickness in females is greater May indicate females process certain information better than males Multiple sclerosis destroys myelin sheath Biological foundations of Behavior

7. Neural Transmission

8. Neurotransmitters and Synaptic Transmission Neurons work together through Synapse Synaptic gap Neurotransmitters: excitatory, inhibitory Synaptic vesicles Synaptic terminals Receptor sites Brain can be altered by use of drugs Biological foundations of Behavior

9. Neurotransmitters and Synaptic Transmission Glial cells Outnumber neurons Produce myelin sheath Uses chemical ATP (adenosine triphosphate) Biological foundations of Behavior Chemicals in brain –Acetylcholine –Dopamine –Serotonin –Norepinephrine –Glutamate –Neuropeptides

10. Divisions of the Nervous System Central Nervous System Brain and spinal cord Interneuron Peripheral Nervous System Branches to all parts of body from CNS Afferent and efferent neurons Biological foundations of Behavior

11. Direction of impulse Muscle contracts and withdraws part being stimulated Axion of efferent neuron Pain receptors in skin Axion of afferent neuron Cell body of interneuron Cell body of afferent neuron Dendrite of afferent neuron Cell body of efferent neuron Hot object

12. Divisions of Peripheral Nervous System Somatic nervous system Voluntary movements and skeletal muscles Receives and send messages Autonomic nervous system Carries messages to organs, has 2 functions Essential body functions Emotion Biological foundations of Behavior

13. Divisions of Autonomic Nervous System Sympathetic nervous system Responds to psychological or physical stress Activates and inhibits organs Parasympathetic nervous system Helps maintain balanced regulation of internal organs and large body muscles Stimulates maintenance activities and energy conservation Biological foundations of Behavior

14. Structures and Functions of the Brain Hindbrain Routine functions that keep body working Three main parts Medulla – breathing and reflexes Pons – balance, hearing Cerebellum – coordinates complex muscle movements Biological foundations of Behavior

15. Hindbrain and Midbrain Medulla Pons Cerebellum Midbrain

16. Structures and Functions of the Brain Reticular formation Spans medulla and pons Influence wakefulness, arousal, attention, Muscle control and cardiac responsiveness Midbrain Center for postural reflexes linked to senses Biological foundations of Behavior

17. Forebrain: Cognition, Motivation, Emotion, and Action Forebrain – two distinct areas Thalamus, hypothalamus, most limbric system Thalamus – message switching station Hypothalamus – motives and emotions Amygdala system – aggression, emotions Hippocampus – memories Biological foundations of Behavior

18. Forebrain Thalamus Hypothalamus Cerebral Cortex

19. Limbic System Cingulate Cortex Septal Area Amydala Hippocampus

20. Forebrain: Cognition, Motivation, Emotion, and Action Forebrain – two distinct areas Primarily cerebral cortex Sensory, cognitive, and motor functions Conscious experiences Voluntary actions Language and intelligence Biological foundations of Behavior

21. Lobes of the Cerebral Cortex Lobes – four sections of brain Frontal lobes – thinking, memory, decisions Broca’s area – ability to speak Phineas Gage Association areas – general roles in cerebral activities Biological foundations of Behavior

22. Wernicke’s area Broca’s area Motor area Somatosensory Voluntary movement and thinking Body sensations Vision Hearing The Brain’s Four Lobes

23. Images of the Brain at Work Techniques create images Electroencephalogram (EEG) Positron emission tomography (PET) Magnetic resonance imaging (MRI) Functional MRI measures Biological foundations of Behavior

24. Functions of the Hemispheres of the Cerebral Cortex Biological foundations of Behavior Corpus Callosum

25. Functions of the Left and Right Cerebral Hemispheres Left cerebral hemisphere Language control in 90% of population Analyzes logical verbal information Right cerebral hemisphere Processes shapes and location of things Visual and spatial information Corpus callosum Biological foundations of Behavior

26. Split Brains Severed corpus callosum Psychological experiments reveal processing limitations of hemispheres Optic chiasm not severed Biological foundations of Behavior

27. Hemispheres of the Cerebral Cortex and Emotion Left hemisphere Processes positive emotions Stroke in left hemisphere – depression Right hemisphere Processes negative emotions Stroke in right hemisphere – no depression Plasticity of cortex Biological foundations of Behavior

28. Human Diversity: Sex Differences in the Cerebral Cortex Female brain – average size smaller than that of male brain More folds and complex Greater surface area More accurate in verbal task performance More activation in left cerebral hemisphere Male brain More activation in right cerebral hemisphere Biological foundations of Behavior

29. The Brain is a Developing System Brain structure changes over lifetime Total brain weight same after age 5 Gray matter decreases as white matter increases in cerebral cortex White matter: continued myelin growth but decreases after fifth decade of life Gray matter decrease: neural pruning Neurogenesis: controversial issue Biological foundations of Behavior

30. The Brain is an Interacting System Cerebral cortex – evaluates threats Limbic system – process emotional arousal Motor areas of cortex work with hindbrain and midbrain to coordinate muscular movements Parallel rather than serial processing Biological foundations of Behavior

31. Endocrine System: Chemical Messengers of the Body Endocrine system – regulation of bodily processes Glands – secrete neuropeptides and hormones Hormones Directly regulated by brain Chemically identical to some neurotransmitters Activate body organs during physical stress or emotional arousal Biological foundations of Behavior

32. Glands Pituitary Gland Largely controlled by hypothalamus Regulates body’s reaction to stress and resistance to disease Adrenal glands Pair of glands atop kidney Secrete variety of hormones in emotional arousal Epinephrine and norepinephrine Cortisol Biological foundations of Behavior

33. Islets of Langerhans Embedded in pancreas – regulate sugar in blood Glucagon – causes liver to put sugar in blood stream Insulin – reduces sugar level in blood Biological foundations of Behavior

34. Glands Gonads – produce sex cells Ovaries and estrogen Testes and testosterone Thyroid gland Regulation of metabolism Secretes thyroxin Serious deficiency: cretinism, rare type of mental retardation Biological foundations of Behavior

35. Glands Parathyroid glands Four small glands in thyroid Secrete parathormone Regulates ion levels in neurons Too much – lethargy Too little – excessive nervous activity Pineal gland Attached to top of thalamus Secretes melatonin – regulates moods Biological foundations of Behavior

36. Genetic Influences on Behavior What is inherited? Physical traits Specific behavioral patterns Biological mechanisms of inheritance Genetic codes Mendel – science of genetics Genes, chromosomes, and DNA Biological foundations of Behavior

37. Genetic Influences on Behavior Biological mechanisms of inheritance Sex cells Gametes Fertilization and zygote Dominant and recessive genes and traits Chromosome abnormalities Down syndrome Genes influence on mental processes Biological foundations of Behavior

38. Research on Inheritance in Humans Studies of twins Monzygotic: identical twins Dizygotic: fraternal twins Studies of adopted children Heredity and environmental influences Biological foundations of Behavior

39. Biological Foundations of Behavior