reflexes, brain very good

8/3/2019 Reflexes, Brain VERY GOOD

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Essentials of Anatomy and Physiology

Fifth edition

Seeley, Stephens and Tate

Slide 2.1Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Chapter 8: Nervous System


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The Reflex Arc


Reflex rapid, involuntary responses tostimuli

Reflex arcOne kind of conductionpathway

Figure 7.11a


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The Reflex Arc


Reflex Arc components:

Usually five (5), may be fewer

Receptor, sensory neuron, integrationcenter, motor neuron, effector

Figure 7.11a


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The Reflex Arc


Reflex arcfrom receptor tointerneuron, to effector

Impulse may notgo to brain beforereflex occurs

Figure 7.11a


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Simple Reflex Arcs


Figure 7.11b, c


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Types of Reflexes and Regulation


Involuntary (Autonomic) reflexes:

Smooth muscle regulation

Heart and blood pressure regulationRegulation of glands (secretion)

Digestive system regulation


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Types of Reflexes and Regulation


Somatic reflexes

Activation of skeletal musclesInvoluntary movement of a voluntarymuscle


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The Meninges

The meninges are layersof tissue that separate theskull and the brain.

Skull

Dura mater

Arachnoid Layer

Pia Mater

Brain


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External Brain Structures


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The Cerebrum

The largest portion of the brainis the cerebrum. It consists oftwo hemispheres that areconnected together at thecorpus callosum.

The cerebrum is often dividedinto five lobes that areresponsible for different brainfunctions.

Corpus callosum


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Lobes of the Cerebrum

Parietal Lobe

Temporal Lobe

Frontal Lobe

Occipital Lobe


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Central Nervous System (CNS)


CNS develops from the embryonicneural tube

Two components:Brain

Spinal Cord


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Lobes of the Cerebrum, median view

Slide 7.29bCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 7.15a


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Specialized Functions of Lobes

Slide 7.32aCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Frontal Lobes:

Voluntary movement

ConcentrationPlanning

Problem-solving

Judging consequences of behavior

Brocas area: speech output


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Parietal Lobes:

Sensations from skin: pressure,

temperature, touch,pain

Speech: use, understanding

Input of language Interpretation


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Temporal Lobes:

Interpretation of sound

Hearing

Interpretation of smell

Direct input from olfactory nerves

Limbic system


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Occipital Lobes:

Vision

Combining vision with other senses

Recognition of objects, individuals


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Insula:

fifth lobe

Hidden in lateral fissure

Monitors internal organs, i.e., heart

Responsible for aversions


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Specialized Area of the Cerebrum

Slide 7.32cCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 7.13c


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Layers of the Cerebrum


Gray matter

Outer layer

Composed ofneuron cell

bodies

Figure 7.13a


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Slide 7.33bCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

White matter

Fiber tracts

deep to graymatter

myelinated

Example:corpus callosum

Figure 7.13a


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Slide 7.33cCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Basal nuclei internal islands ofgray matter

Buried in white matter ofhemispheres

Assist with posture, balance,

location of sound

Figure 7.13a


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Diencephalon


Sits above brain stem

Enclosed by the cerebral hemispheres

Made of three parts

Thalamus

Hypothalamus

Epithalamus (with pineal body)


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Regions of the Brain


Diencephalon di = through or

throughout

Figure 7.12


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Diencephalon

Slide 7.34bCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 7.15


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Thalamus


Surrounds the third ventricle

The relay station for sensory impulsesException: sense of smell

Transfers impulses to the the cortex forinterpretation


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Thalamus

Figure 7.12


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Hypothalamus


Under the thalamus Important autonomic nervous system

center

Helps regulate body temperatureControls water balance

Regulates metabolism


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Hypothalamus

Figure 7.12


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Hypothalamus

Slide 7.36bCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

An important part of the limbic system(emotions)

The pituitary gland is attached to thehypothalamus

Hypothalamus produces hormone releasing

factors Control anterior pituitary gland


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Epithalamus


Forms the roof of the third ventricle

Houses the pineal body(an endocrinegland)

Includes the choroid plexus forms

cerebrospinal fluid


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Brain Stem


Attaches brain to the spinal cord

Parts of the brain stem

Midbrain

Pons

Medulla oblongata


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Brain Stem

Slide 7.38bCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 7.15a


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Midbrain


Mostly composed of tracts of nervefibers (myelinated)

Has four rounded protrusions:corpora quadrigemina

Reflex centers for vision and hearing


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Pons


Pons means bridge

The bulging center part of the brain

stem Mostly composed of fiber tracts

Includes nuclei involved in the control ofbreathing


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Medulla Oblongata


The most inferior part of the brain stem Attaches to the spinal cord

Houses control centers

Heart rate control

Blood pressure regulation

Breathing

Swallowing

Vomiting


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reflexes, brain very good

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