1. FUNDAMENTALS OF ANATOMY AND PHYSIOLOGY
Mrs. Willie Grant, Instructor
(210)

3. An Introduction to the ANS and Higher-Order Functions
Learning Outcomes
16-1 Compare the organization of the autonomic nervous system with that of the somatic nervous system.
16-2 Describe the structures and functions of the sympathetic division of the autonomic nervous system.
16-3 Describe the mechanisms of sympathetic neurotransmitter release and their effects on target organs and tissues.
16-4 Describe the structures and functions of the parasympathetic division of the autonomic nervous system.
16-5 Describe the mechanisms of parasympathetic neurotransmitter release and their effects on target organs and tissues.
16-6 Discuss the functional significance of dual innervation and autonomic tone.
16-7 Describe the hierarchy of interacting levels of control in the autonomic nervous system, including the significance of visceral reflexes.
16-8 Explain how memories are created, stored, and recalled, and distinguish among the levels of consciousness and unconsciousness.
16-9 Describe some of the ways in which the interactions of neurotransmitters influence brain function.
Summarize the effects of aging on the nervous system and give examples of interactions between the nervous system and other organ systems.

4. An Introduction to the ANS and Higher-Order Functions
Somatic Nervous System (SNS) Operates under conscious control Seldom affects long-term survival SNS controls skeletal muscles Autonomic Nervous System (ANS) Operates without conscious instruction ANS controls visceral effectors Coordinates system functions Cardiovascular, respiratory, digestive, urinary, reproductive

5. 16-1 Autonomic Nervous System
Organization of the ANS Integrative centers For autonomic activity in hypothalamus Visceral motor neurons In brain stem and spinal cord, are known as preganglionic neurons Preganglionic fibers Axons of preganglionic neurons Leave CNS and synapse on ganglionic neurons Neurons comparable to upper motor neurons in SNS Visceral Motor Neurons Autonomic ganglia Contain many ganglionic neurons Ganglionic neurons innervate visceral effectors Such as cardiac muscle, smooth muscle, glands, and adipose tissue Postganglionic fibers Axons of ganglionic neurons

7. 16-1 Divisions of the ANS
The Autonomic Nervous System
Operates largely outside our awareness
Has two divisions
Sympathetic division
Increases alertness, metabolic rate, and muscularabilities
“Kicks in” only during exertion, stress, or emergency
“Fight or flight”
Parasympathetic division
Reduces metabolic rate and promotes digestion
Controls during resting conditions
“Rest and digest”

8. Sympathetic and Parasympathetic Division
16-1 Divisions of the ANS
Sympathetic and Parasympathetic Division
Most often, these two divisions have opposing effects
If the sympathetic division causes excitation, the parasympathetic causes inhibition
The two divisions may also work independently
Only one division innervates some structures
The two divisions may work together, with each controlling one stage of a complex process
1 Because the sympathetic division of the ANS stimulates tissue metabolism and increases alertness, it is called the _____ subdivision.
2 Because the parasympathetic division of the ANS conserves energy and promotes sedentary activity, it is known as the ____ subdivision.
3 A third division of the ANS is the _____________.

10. 16-1 Divisions of the ANS
Seven Responses to Increased Sympathetic Activity
Heightened mental alertness
Increased metabolic rate
Reduced digestive and urinary functions
Energy reserves activated
Increased respiratory rate and respiratory passageways dilate
Increased heart rate and blood pressure
Sweat glands activated
Five Responses to Increased Parasympathetic Activity
Decreased metabolic rate
Decreased heart rate and blood pressure
Increased secretion by salivary and digestive glands
Increased motility and blood flow in digestive tract
Urination and defecation stimulation

11. 16-4 The Parasympathetic Division
Major Effects of Parasympathetic Division
Constriction of the pupils
Secretion by digestive glands
Secretion of hormones
Changes in blood flow and glandular activity
Increase in smooth muscle activity
Stimulation and coordination of defecation
Contraction of the urinary bladder during urination
Constriction of the respiratory passageways
Reduction in heart rate and in the force of contraction

12. Table 16-2 A Structural Comparison of the Sympathetic and Parasympathetic Divisions of the ANS
4 The sympathetic effects on the eye is to _____, while the parasympathetic effect on the eye is to ____________.
5 The sympathetic effects on the heart is to _______________, while the parasympathetic effect on the heart is to _________________. 12

17. 16-8 Higher-Order Functions
Higher-Order Functions Share Three Characteristics
Require the cerebral cortex
Involve conscious and unconscious information processing
Are not part of programmed “wiring” of brain

18. 16-8 Higher-Order Functions
Memory
Fact memories (are specific bits of information)
Skill memories (are learned motor behaviors that are incorporated at unconscious level with repetition)
Short-term memories
Information that can be recalled immediately
Contain small bits of information
Primary memories
Long-term memories
Memory consolidation – conversion from short-term to long-term memory
Two types of long-term memory
Secondary memories fade and require effort to recall
Tertiary memories are with you for life
6 The loss of memory as a result of disease or trauma is ________.

19. 7 The conversion from short-term to long-term memory is called _____.

20. 16-8 Higher-Order Functions
States of Consciousness
Degree of wakefulness indicates level of ongoing CNS activity
When abnormal or depressed, state of wakefulness is affected
Deep sleep
Also called slow-wave or Non-REM (NREM) sleep. The entire body relaxes and the cerebral cortex activity is minimal.
Rapid eye movement (REM) sleep. When active dreaming occurs.
Changes in blood pressure and respiratory rate
Less receptive to outside stimuli than in deep sleep
Muscle tone decreases markedly
Eyes move rapidly as dream events unfold

22. 16-8 Higher-Order Functions
States of Consciousness
Nighttime sleep pattern alternates between levels
Begins in deep sleep
REM periods average 5 minutes in length; increase to 20 minutes over 8 hours

23. 16-8 Higher-Order Functions
Sleep
Has important impact on CNS
Produces only minor changes in physiological activities of organs and systems
Protein synthesis in neurons increases during sleep
Extended periods without sleep lead to disturbances in mental function
25% of the U.S. population experiences sleep disorders
8 The degree of wakefulness at any moment is an indication of the level of ongoing ___ activity.
9 Active dreaming occurs during _____ sleep.

24. 16-8 Higher-Order Functions
States of Consciousness Arousal and the reticular activating system (RAS) Awakening from sleep Function of reticular formation Extensive interconnections with sensory, motor, integrative nuclei, and pathways along brain stem Determined by complex interactions between reticular formation and cerebral cortex Ending sleep Any stimulus activates reticular formation and RAS Arousal occurs rapidly Effects of single stimulation of RAS last less than a minute

25. Arousal and the Reticular Activating System
Maintaining consciousness Activity in cerebral cortex, basal nuclei, and sensory and motor pathways continue to stimulate RAS After many hours, reticular formation becomes less responsive to stimulation Individual becomes less alert and more lethargic Neural fatigue reduces RAS activity Regulation of sleep–wake cycles Involves interplay between brain stem nuclei that use different neurotransmitters Group of nuclei stimulates RAS with NE and maintains awake, alert state Other group promotes deep sleep by depressing RAS activity with serotonin “Dueling” nuclei located in brain stem

27. 16-10 Effects of Aging on the Nervous System
Anatomical and physiological changes begin after maturity (age 30) and they acumulate over time
85% of people over age 65 have changes in mental performance and CNS function
Common Age-related Anatomical Changes in the Nervous System
Reduction in Brain Size and Weight (reduction in cerebral cortex)
Reduction in Number of Neurons (reduction in cortical neurons)
Decrease in Blood Flow to Brain (fatty acid deposits that reduce blood flow)
Changes in Synaptic Organization of Brain (decreased dendritic branches, spines and interconnections)
Intracellular and Extracellular Changes in CNS Neurons (accumulate abdormal deposits)
10 An example of an abnormal intracellular deposit is _________.

28. 16-10 Effects of Aging on the Nervous System
Anatomical Changes
Linked to functional changes
Neural processing becomes less efficient with age
Memory consolidation more difficult
Secondary memories harder to access
Sensory Systems
Hearing, balance, vision, smell, and taste become less acute
Reaction times slowed
Reflexes weaken or disappear
Motor Control
Precision decreases
Takes longer to perform

29. 16-10 Effects of Aging on the Nervous System
Incapacitation
85% of elderly population develops changes that do not interfere with abilities
Some individuals become incapacitated by progressive CNS changes
Senility (senile dementia)
Degenerative changes: Memory loss, anterograde amnesia (lose ability to store new memories), emotional disturbances, Alzheimer’s disease is most common
11 The most common and disabling form of senile dementia is ______.

30. 16-10 Nervous System Integration
The Nervous System
Monitors all other systems
Issues commands that adjust their activities
Like conductor of orchestra
12 Alzheimer’s disease (AD) is _________________________________________.

31. Clinical Case—The First Day in Anatomy Lab
Why would the instructor tell Tim to lie down, or want him to get his head below his heart, the
Next time he feels faint?
In addition to the cardiac plexus, where else in the body would the sympathetic nervous system act during Tim’s recovery?