1. Nervous System Outline
Health Occupations

3. Nervous System Functions
Directs the functions of all human body systems
100 Billion Nerve cells
Carry messages from brain to rest of body

4. Neurons The basic element of nervous system Highly specialized
Vary in function, shape, and size
Separated by synapses
Gaps in between each neuron
Neurotransmitters
Stimulates impulse to jump to next nerve

6. Neurons 3 Parts Cell Body Dendrites Axon
Have fibers to reach out to send or
receive impulses
Dendrites
Thin branching extensions of cell body
Conduct nerve impulses to cell body
Axon
Conducts nerve impulses away from cell body
Covered by a myelin sheath
Fatty tissue that makes impulse travel faster
End of axon has fibers that let the impulse leave the nerve

8. Neurons 2 Basic Properties Excitability Conductivity
Ability to respond to a stimulus
Conductivity
Ability to transmit a signal

9. Neurons 3 Types Efferent (motor) Afferent (sensory) Interneurons
Carry information to muscles and glands from CNS
Afferent (sensory)
Carry information from sensory system to CNS
Interneurons
Carry and process sensory information

10. Neuron bundles = Nerves
Stimulus Receptor Impulse
Nerve Receptor

11. Neuroglias Support, connect, protect, and remove debris
Do not transmit impulses
Form blood-brain barrier
Permits some chemical substances to reach the brain’s neurons but blocks most others

12. Central Nervous System (CNS)
Consists of:
Brain
Spinal cord
Center of Control

14. CNS Functions Receives and interprets all stimuli
Sends nerve impulses to instruct muscles and glands to take over or respond to certain actions
Causes Voluntary and Involuntary actions

16. Brain Divisions
Brainstem
Cerebellum
Cerebrum
Diencephalon

17. Brain Stem Midbrain Pons Medulla Oblongata Visual reflexes
Controls certain respiratory functions
Medulla Oblongata
Regulates heart & lung functions
Swallowing
Vomiting
Coughing
sneezing

18. Cerebellum Coordinates musculoskeletal movement Maintains balance
Posture
Muscle tone

20. Cerebrum 2 hemispheres Cerebral Cortex Four Lobes Left and Right
Conscious decision making
Four Lobes
Frontal
Moral Behavior, voluntary motor movements
Parietal
Controls and interprets senses and taste
Temporal
Memory, equilibrium, emotion, hearing
Occipital
vision

21. Diencephalon Deep portion of brain Contains:
Thalamus
Hypothalamus
Relay center for sensations
Controls:
Heart rate
Blood pressure
Temperature regulation
Water and electrolyte balance
Digestive functions
Glandular activities

22. Cerebrospinal Fluid (CSF)
Fills the area between the brain and cranium
Watery fluid that contains various compound
Cradles and cushions brain

23. Spinal Cord
Extends from base of brain to first lumbar vertebrae in back
Protected by:
Cerebrospinal fluid
Vertebral column
Meninges
3 layers of membranes that cover brain and spinal cord

24. Meninges Dura Mater (outer layer) Arachnoid Mater (middle layer)
Tough, fibrous
Contains channels for blood to enter brain tissue
Arachnoid Mater (middle layer)
Web-like structure
Pia Mater (innermost layer)
Contains blood vessels that nourish spinal cord

26. Peripheral Nervous System
12 Cranial Nerves
Carry impulses to and from the brain
31 pairs of spinal nerves
Carry messages to and from the spinal cord and the torso and extremities of the body

27. Peripheral Nervous System
2 Subsystems according to function
Somatic Nervous System
Autonomic Nervous System

28. Somatic Nervous System
Receive and process sensory input from the skin, muscles, tendons, joints, eyes, tongue, nose and ears
Excite voluntary contraction of skeletal muscles

30. Autonomic Nervous System
Carry impulses from the central nervous system to glands, various involuntary muscles, cardiac muscle, and membranes
Stimulates organs, glands and senses by stimulating secretions of substances
Divided into sympathetic and parasympathetic divisions

31. Autonomic Nervous System
Sympathetic
Operates when the body is under stress
Activates responses necessary to react in dangerous or abnormal situations
Fight or Flight response
Parasympathetic
Operates to keep the body in homeostasis under normal conditions

32. The End