1. Introduction to Anatomy & Physiology The Nervous System
Packet #34
Chapter #29

2. Anatomy & Physiology Introduction
Study of structure and relationship between body parts
Physiology
Study of the function of the body parts and the body as a whole

3. Anatomy & Physiology Study Areas
Cytology
The study of cells at microscopic level
Histology
Study of tissue at microscopic level

4. The Nervous System

5. Introduction The nervous system has three main functions Sensory Input
Integration
Sensory Output

6. Introduction II
Radically symmetric invertebrate organisms utilize nerve nets and radial nervous systems
Cnidarians have a nerve net of cells scattered throughout the body.
There is no central control organ
Echinoderms, such as star fish , typically have a radial nervous system.
Nerve ring
Nerves that extend to various parts of the body
Bilateral nervous systems are characteristic of bilaterally symmetrical animals

7. The Human Nervous System

8. Nerves Neurons Basic functional units of the human nervous system
Three categories of neurons
Sensory
Interneurons
Motor neurons

9. Neurons II Sensory (Afferent) Neurons
Receives stimuli from environment
Transmits impulses from skin and other sensory organs towards the CNS
Ears; eyes; nose; tongue

10. Nerves III Interneurons Motor (Efferent) Neurons
Interprets impulses brought by sensory neurons
Submits “commands” to the motor neurons
Leads back to effector organs
Motor (Efferent) Neurons
Transmit impulses from the CNS to effectors
Target cells that produce some kind of response
Muscles
Glands

11. Parts of the Human Nervous System

12. Human Nervous System I
The human nervous system can be divided into two major categories
The Central Nervous System
The Peripheral Nervous System

13. The Central Nervous System

14. Introduction
The central nervous system is composed of two main parts: -
The Brain
The Spinal Cord

15. Brain Cerebrum Cerebellum Medulla Contains center for learned behavior
Center for thought, memory and reasoning
Cerebellum
Controls balance & muscular activities
Medulla
Controls involuntary functions
Heartbeat; breathing; blood pressure

16. Spinal Cord
The spinal cord, in addition to helping move messages to the brain, allows the organism to reflex rapidly and involuntary in response to a stimulus
The message only travels through the spinal cord and not the brain
The Reflex Arc
Pathway traveled by nerve impulses during a reflex

17. Peripheral Nervous System

18. Peripheral Nervous System
The PNS includes all nerves, of all types, that branch through the body from the CNS
Consist of all nerves outside of the brain and spinal cord
Has two divisions
Somatic Nervous System
Autonomic Nervous System

19. Somatic Nervous System
Consists of motor neurons that stimulate skeletal muscles
Control actions at voluntary skeletal muscle.

20. Autonomic Nervous System
Include only motor neurons that control the activities of
Organs
Glands
Various involuntary muscles
Cardiac and smooth muscle
Two parts
Sympathetic Nervous System
Parasympathetic Nervous System
The somatic nervous system controls voluntary actions while the autonomic nervous system controls involuntary actions

21. Sympathetic Nervous System
Prepare the body for action
Prepare body for situations requiring alertness or strength or situations that arouse fear anger, excitement or embarrassment (fight or flight)
Responses that serve to fight of or retreat from danger

22. Parasympathetic Nervous System
Activates “calm” functions
Stimulates the processes of digestion, urination and defecation
Reduces blood pressure, heart and respiratory rates
Conserves energy through relaxation and rest

23. The Nervous System Overview
Central Nervous System
Brain
Cerebrum
Cerebellum
Medulla
Spinal Cord
Peripheral Nervous System
Somatic (Voluntary)
Autonomic (Involuntary)
Sympathetic
Action
Parasympathetic
Calm