1. Nervous System Maintaining homeostasis a billion messages at a time…

3. Functions Monitor changes: sensation – Stimuli: sensory input (receptors) – Internal and external Integrate – Processes – Interprets – Generates response Respond – Motor output – Activates effector organs

5. Cell Type Neurons

6. Neurons use two types of signals to communicate: – electrical signals (long-distance) – chemical signals (short-distance)

7. Cell Communication

9. Interpreting signals in the nervous system involves sorting a complex set of paths and connections Processing of information takes place in simple clusters of neurons called ganglia or a more complex organization of neurons called a brain © 2011 Pearson Education, Inc.

10. Ganglia Brain Arm Nerve Eye Mantle Nerves with giant axons Figure 48.2

11. Sensors detect external stimuli and internal conditions and transmit information along sensory neurons Sensory information is sent to the brain or ganglia, where interneurons integrate the information Motor output leaves the brain or ganglia via motor neurons, which trigger muscle or gland activity © 2011 Pearson Education, Inc.

13. Two divisions Central nervous system (CNS) – brain and spinal cord – Center for integration and control Peripheral nervous system (PNS) – Nerves and assoc. cells outside of CNS – Spinal nerves: carry information to and from the spinal cord – Cranial nerves: carry information to and from the brain

14. Figure 48.3 Sensor Effector Sensory input Motor output Integration Peripheral nervous system (PNS) Central nervous system (CNS)

16. Central Nervous System Integration and command center – Relays messages – Processes information – Analyzes information – Dictates motor responses

17. Peripheral Nervous System Communication lines Link all parts of the body to the CNS

18. Find this diagram

19. Divisions of the PNS Sensory (Afferent) Division: TO the CNS – Somatic afferent fibers: skin, skeletal muscles, joints – Visceral afferent fibers: visceral organs Motor (Efferent) Division: FROM the CNS – Stimulates effector organs – Effect (bring about) motor response Contraction Secretion

21. Branches of the Motor Division Somatic Nervous System – Somatic motor nerve fibers – CNS to skeletal muscles – Voluntary – conscious control Autonomic Nervous System – Visceral motor nerve fibers – CNS to smooth and cardiac muscles and glands – “a law unto itself” - involuntary

22. And finally: divisions of the Autonomic Nervous System Control same visceral organs Opposite effects: antagonistic Sympathetic: fight or flight – Emergency situations – mobilization Parasympathetic: rest and digest – Nonemergency functions – Conserves energy

23. Sympathetic Release adrenaline and noradrenaline Increases heart rate and blood pressure Increases blood flow to skeletal muscles Inhibits digestive functions CENTRAL NERVOUS SYSTEM Brain Spinal cord SYMPATHETIC Dilates pupil Stimulates salivation Relaxes bronchi Accelerates heartbeat Inhibits activity Stimulates glucose Secretion of adrenaline, nonadrenaline Relaxes bladder Stimulates ejaculation in male Sympathetic ganglia Salivary glands Lungs Heart Stomach Pancreas Liver Adrenal gland Kidney

24. Parasympathetic Calms body to conserve and maintain energy Lowers heartbeat, breathing rate, blood pressure CENTRAL NERVOUS SYSTEM Brain PARASYMPATHETIC Spinal cord Stimulates salivation Constricts bronchi Slows heartbeat Stimulates activity Contracts bladder Stimulates erection of sex organs Stimulates gallbladder Gallbladder Contracts pupil

25. Summary of autonomic differences Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Parasympathetic division (calming) Pupils dilate EYES Pupils contract Decreases SALIVATION Increases Perspires SKIN Dries Increases RESPIRATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones

27. Root Words Peri: about, around, enclosing, surrounding Visc: of or pertaining to the internal organs Soma: body Auto: self

28. Brain: basic anatomy

29. Cerebrum Controls voluntary, conscious activities of the body

30. Cerebellum Coordinates and balances actions of muscles

31. Brain Stem Connects brain and spinal cord Regulate flow of information between brain and rest of the body Hearing and visual reflexes Control over several automatic homeostatic functions: breathing, heart and blood vessel activity, swallowing, vomiting, digestion

32. Thalamus Receives messages from sense organs and directs to cerebrum for further processing

33. Hypothalamus Control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature Central biological clock Regulates pituitary gland (via hormone action…so this guy also belongs to the endocrine system)

34. The Cerebral Cortex Cerebrum divided into four lobes – named for the skull bones that cover them…

35. Named for the parts of the skull they sit under

36. Lobes of the cerebrum…