The document provides an overview of the nervous system, including its main functions, anatomy, and divisions. The nervous system coordinates movement, senses the environment, and integrates senses. It is composed of neurons and neuroglial cells and uses electrochemical signals to communicate via nerves between parts of the body. The nervous system can be divided into the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which connects the CNS to the rest of the body. The PNS is further divided into the autonomic nervous system, which controls involuntary functions, and the somatic nervous system, which controls voluntary functions.

1. Introduction to the Nervous System Chapter 9: Nervous System Unit 3: Integration and Coordination

2. Nervous System Function The nervous system performs three primary functions in the human body 1. The most obvious is that it coordinates our movements using electrochemical signals to control muscle contraction. 2. Also used to sense the internal & external environment 3. Finally, it integrates senses to form emotions and sensations

3. Nervous System Function Overall the Nervous system is one of two systems that helps to maintain that all important homeostasis Uses sensors and effectors to maintain important physiological set points. *the other system that helps maintain homeostasis would be the endocrine system

4. Nervous System Anatomy The structural basis of the nervous system is a special cell called the neuron There are additional cells in the nervous system called neuroglial cells Perform support roles such as absorbing nutrients and phagocitizing pathogens in the nervous system

5. Nervous System Anatomy Neurons are specialized cells that are capable of carrying electrochemical signals long distances Specialized ion channels Specialized ion pumps Lots of ATPase

6. Nervous System Anatomy

7. Nervous System Anatomy Neurons have three distinct parts Cell body Dendrites (many) Axon (single)

8. Nervous System Anatomy Nervous system uses nerves to communicate between body parts Nerves are bundles of axons from multiple neurons Act like telephone wires in the body

9. Divisions of the NS The nervous system and its organs can be divided into two major groups: Central Nervous System ( CNS ) Includes the brain & spinal cord Peripheral Nervous System ( PNS ) Includes the nerves and ganglia that connect the CNS to the rest of the body

10. Divisions of the NS CNS Responsible for integration of senses Development of emotions Coordinates movements

11. Divisions of the NS PNS Responsible for sensory functions The five senses Can use free nerve ends such as those used to sense heat/cold OR… Be connected to specialized sense organs such as the cones/rods of the retina (eye), the taste buds, or the special organs that sense touch and pressure in the skin

12. Divisions of the NS PNS Also responsible for motor functions Telling muscles when to contract Controlling heart rate Controlling blood pressure by making vessels constrict/dilate (also controls temperature homeostasis) Controlling breathing

13. Divisions of the NS The motor part of the peripheral nervous system can be further divided into two categories based on responsiveness: The Autonomic Nervous System The Somatic Nervous System

14. Divisions of the NS Autonomic Nervous System Controls and coordinates parts of the body that are not under voluntary control Called involuntary actions Heart rate Blood Pressure Digestion

15. Divisions of the NS Somatic Nervous System Responsible for all actions that are preformed voluntarily Skeletal muscle contractions

16. Divisions of the NS The Autonomic Nervous System can be divided still farther into two groups that affect the human body in opposite ways Sympathetic Nervous System Parasympathetic Nervous System

17. Divisions of the NS The Sympathetic Nervous System Part of the autonomic nervous system Responds involuntarily to danger/stress Results in the fight or flight response Heart rate??? Blood pressure??? Pupils??? Digestion???

18. Divisions of the NS The Parasympathetic Nervous System Responds involuntarily Results in a soothing/calming response Usually responds once a stressful/fearful stimulus is removed