Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS)
Nervous System - PNS and CNS Biol 105 Lecture Packet 10 Chapter 8.
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Transcript of Nervous System - PNS and CNS Biol 105 Lecture Packet 10 Chapter 8.
Nervous System - PNS and CNS
Biol 105
Lecture Packet 10
Chapter 8
Copyright © 2009 Pearson Education, Inc.
OutlineI. Central Nervous System vs Peripheral Nervous
SystemII. Peripheral Nervous System
A. Autonomic Nervous SystemsB. Somatic Nervous Systems
III. Autonomic Nervous SystemA. Parasympathetic Nervous SystemsB. Sympathetic Nervous Systems
IV. Reflex ActionsV. Central Nervous System
A. Protection of CNSB. Spinal CordC. Brain
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Two Parts of the Nervous System
Central Nervous System (CNS) Brain and Spinal Cord
Peripheral Nervous System (PNS) Nervous tissue outside brain and
spine Sense organs
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Somatic nervous system – part of PNS that controls voluntary functions Movement, controls skeletal muscles
Autonomic nervous system – part of PNS that control involuntary functions Controls cardiac and smooth muscles, and
glands
Peripheral Nervous System
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Figure 8.1 The nervous system
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Autonomic Nervous System
Autonomic Nervous System is divided into two systems:
Parasympathetic division – “rest and digest”
Sympathetic division – stimulatory stress responses (flight or fight responses)
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The PNS - Parasympathetic
Figure 8.12 (1 of 2)
Constrictspupil
Increasessalivation
Decreasesbreathing rate
Slowsheart rate
Widensblood
vessels
Increasesdigestive activity
Increasesdigestive activity
Contractsbladder
muscles
Stimulatesdefecation
Parasympathetic Nervous System(Cranial and sacral
regions of spinal cord)
Synapsebetweenneurons
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Parasympathetic – rest and digest
Constricts eye pupils Stimulate salivation Slows heart rate Constricts breathing Dilates blood vessels Stimulates digestion Constricts bladder Stimulates sex organs
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PNS – Sympathetic Nervous System
Figure 8.12 (2 of 2)
Dilatespupil
Decreasessalivation
Increasesbreathing rate
Increasesheart rate
Narrowsblood vessels
Slowsdigestive activity
Slowsdigestive activity
Relaxes bladder muscles
Inhibitsdefecation
Stimulates secretion of epinephrine and norepinephrine
Causes salt andwater retention
Sympathetic Nervous System(Thoracic and lumbarregions of spinal cord)
Ganglion
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Sympathetic – fight or flight
dilates eye pupils Inhibits salivation Accelerates heart rate Facilitates breathing Stimulates secretion of epinephrine and
norepinephrine Stimulates release of free glucose Inhibits digestion Relaxes bladder Inhibits sex organs
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Reflex Actions
Sometime we need a really quick response – reacting to a hot stove. We may not have time to send the message up to the brain to process the information.
The spinal cord can process the information and send a response back to the motor nerves
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Reflex Arc
The pathway consisting of a sensory receptor, a sensory neuron, interneurons, a motor neuron and an effector (muscle)
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The Spinal Cord
Animation—Reflex ArcsPLAY
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This part of your PNS inhibits digestion
1. Parasympathetic
2. Sympathetic
Parasy
mpathetic
Sympath
etic
50%50%
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Central Nervous System
Brain Spinal cord
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Protection of the CNS
The CNS is protected by:
1. Bone (skull and vertebral column)
2. Meninges
3. Cerebrospinal fluid
4. Blood-Brain barrier
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Meninges
There are three layers of the meninges:
1. Dura mater – outer layer
2. Arachnoid mater – middle layer
3. Pia mater – inner layer
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Meningitis
Meningitis - Inflammation of the meninges
It is caused by many forms of bacteria, viruses and fungi
It can lead to encephalitis, an inflammation of the brain.
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Function of Cerebrospinal Fluid
Functions
1. Shock absorption
2. Support the weight of the brain
3. Nourishment and waste removal
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Blood-brain barrier
Permits certain substances to enter the brain, while inhibiting others from entering
It inhibits many drugs that are not lipid soluble from reaching brain tissue
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Protection of the CNS
Figure 8.2
Ventriclesof the brain
The bones of the skull andvertebral column are hardcases that protect the brainand spinal cord.
Cerebrospinal fluid cushionsthe brain and spinal cord.
The meninges are threemembranes that protectthe brain and spinal cord.
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The innermost layer of the meninges is the:
1. Pia mater
2. Dura mater
3. Arachnoid mater
Pia mater
Dura mater
Arachnoid m
ater
33% 33%33%
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Spinal Cord
Spinal cord extends from the base of the brain down the back – transmits messages between the brain and the rest of the body
There is cerebrospinal fluid in a central canal
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Spinal Cord
If you look at a cross section of the spinal cord you will see “white matter” and “grey matter”
The white matter is myelinated axons
Grey matter is mainly cell bodies and non-myelinated axons
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Spinal Cord
Figure 8.11a
Dorsal root
Dorsal-rootganglion
Pair ofspinal nerves
Gray matter
White matter
Ventral root
(a) View from front of body
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The Brain Cerebrum
Cerebral cortex Hippocampus amygdala
Hypothalamus Thalamus Cerebellum Brain stem – midbrain, pons, medulla oblongata (Pineal gland and Pituitary gland is in the brain
but it is part of the endocrine system)
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The Brain
The Brain is the control center
The cerebral cortex of the cerebrum is the thinking, conscious part of the brain
Cerebrum
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The Brain
Figure 8.3 (2 of 2)
Cerebrum• Contains sensory areas for skin senses, vision, hearing, olfaction• Motor areas for voluntary control of movement• Association areas for interpreting sensations, language, thinking, decision making, self-awareness, creativity, and storage of memories
Corpus callosum• Allows left and right cerebral hemispheres to communicate with one another
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Cerebrum
Contains:
Cerebral cortex Hippocampus Amygdala
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Cerebrum
Functions as the sensory area for touch, vision, hearing, and olfaction as well as association areas for interpreting sensations, language, thinking, decision making, self-awareness, creativity, and storing memories.
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Cerebrum – Cerebral cortex
Cerebral cortex - The thin outer layer of the cerebrum is where most of the higher thinking and processing takes place.
Contains sensory areas (post-central gyrus) Contains motor areas (pre-central gyrus) Prefrontal region of the cerebral cortex is
responsible for decision making Folding increases surface area by about 3x Sulci are the folds or furrows Gyri are the ridges
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Cerebrum – Corpus callosum
Beneath the cortex is white matter
Corpus callosum – band of white matter that connects the two cerebral hemispheres
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Cerebrum – cerebral cortex
Figure 8.4
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Cerebrum
Figure 8.5
Gray matter consists of interneurons, cell bodies, and unmyelinated axons that integrate information.
White matterconsists of myelinated axons that allow communication over long distances.
The corpus callosum is a band of white matter that allowscommunication between thecerebral hemisperes.
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Split Brains
Split Brain Video
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Cerebrum
Hippocampus – important in long term memory
Amygdala – important in remembering fear and responding to it.
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Memory
Figure 8.8
Amygdala
Cerebrum
Hippocampus
Thalamus
Hypothalamus
Olfactory bulb
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Thalamus – Processes sensory information (except smell) and relays it to other areas of brain
Thalamus
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Functions of hypothalamus:
1. maintains homeostasis: Controls heart rate, blood pressure, breathing rate, body temperature
2. regulates drives including hunger, thirst, sex
3. controls the pituitary gland secretions
Hypothalamus
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The Brain
Figure 8.3 (2 of 2)
Hypothalamus• Controls heart rate, blood pressure, breathing rate, body temperature, food intake• Is a center for emotions• Serves as “master biological clock”
Thalamus• Processes all sensory information (except olfaction)• Relays information to appropriate higher brain centers
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Cerebellum – maintains balance and coordination, refines motor skills, new motor skills (playing piano)
Cerebellum
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Cerebellum
Figure 8.3 (1 of 2)
Cerebellum• Coordinates sensory–motor voluntary movement• Stores memory of learned motor patterns
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Brain Stem
Contains:
Medulla oblongata Midbrain Pons
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Brain Stem – Medulla oblongata
Medulla oblongata – controls many vital involuntary functions including breathing, heartbeat and blood pressure
Where the crossing over point is for many neural tracks
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Brain Stem - Pons
Function of the pons:
Assists the medulla oblongata to control involuntary breathing
Relays messages between the spinal cord and the cerebellum with the cerebrum, thalamus, and hypothalmus
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Brain Stem - Midbrain
Functions of Midbrain
Important in voluntary muscle control Relay station for auditory and visual information Relays information between the cerebellum or
spinal cord and the cerebrum Controls eye movement
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The Brain
Figure 8.3 (1 of 2)
Medulla oblongata• Contains autonomic centers for heart rate and digestive activities• Relays sensory information to thalamus
Pons• A bridge between higher and lower brain centers
Midbrain• Relays information between the cerebellum or spinal cord and the cerebrum• Integrates sensory input
Bra
inst
em
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Glands
Pituitary gland and pineal glands are part of the brain but will be covered in the endocrine system
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What region of the brain is the region where most of the higher thinking and processing takes place
1. Amygdala
2. Hippocampus
3. Cerebral cortex
4. Hypothalamus
Amygdala
Hippocampus
Cerebral co
rtex
Hypothalamus
25% 25%25%25%
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What region of the brain is the region important in long term memory
1. Amygdala
2. Hippocampus
3. Cerebral cortex
4. Hypothalamus
Amygdala
Hippocampus
Cerebral co
rtex
Hypothalamus
25% 25%25%25%
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What region of the brain regulates drives including hunger, maintains homeostasis, controls the pituitary gland
1. Amygdala
2. Hippocampus
3. Cerebral cortex
4. Hypothalamus
Amygdala
Hippocampus
Cerebral co
rtex
Hypothalamus
25% 25%25%25%
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What region of the brain is important in remembering fear and
responding to it.
1. Amygdala
2. Hippocampus
3. Cerebral cortex
4. Hypothalamus
Amygdala
Hippocampus
Cerebral co
rtex
Hypothalamus
25% 25%25%25%
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What are the somatic nervous system and autonomic nervous system, what do they control?
What are reflex actions?
What are the Parasympathetic division and the Sympathetic division – what specifically do they control (increase heart rate, etc)
Important Concepts
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What protects the CNS
What are the three layers of the meninges, be able to describe them and their location (which is the inner, middle or outer layer.
What is meningitis, what is the cause, what is encephalitis
What are the functions of cerebrospinal fluid
What is the function of the blood-brain barriers, what does it allow to pass?
Important Concepts
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Major regions of the brain and their functions: Cerebrum (including the cerebral cortex, hippocampus, and amygdala), Hypothalamus, Thalamus, Cerebellum, Brain stem (including the midbrain, pons, and medulla oblongata)
What parts of the brain are in the cerebrum and in the brain stem
What is the corpus callosum and what is its function?
Important Concepts
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Important Concepts
What are split brains and how does that effect a person
Where are the primary motor and somatosensory areas of the cortex
How are body parts represented on the cortex
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Definitions
Long term memory, somatic nervous system, autonomic nervous system, voluntary, involuntary, reflex arc, constrict, dilate, inhibits, accelerates, facilitates, stimulates, relaxes, white matter, grey matter, prefrontal region,