Test Five Review
1. List and describe the
characteristics of the major
subdivisions of the nervous system
2. List, describe and give the functions
of the neuroglia found in the CNS and
the PNS.
Neuroglia
• Provide the support for neurons via glia cells
• Six types
– In the CNS
•
•
•
•

Astrocytes
Microglia
Ependyma...
Astrocytes (CNS)
• Most abundant, versatile & highly branched
glia cells
• They cling to neurons w/ their synaptic
endings...
Microglia (CNS)
1. Small ovoid cell w/
“thorny” processes that
touch nearby neurons
2. Function:
• Monitor health (migrate...
Ependymal Cells (CNS)
1. Range in shape from squamous to
columnar
2. Line central cavities of the brain & spinal
column fo...
Oligodendrocytes (CNS)
1. Produce myelin
sheaths
• Insulating
coverings
Peripheral Nervous System (PNS)
1. Satellite Cells: function still unknown
2. Schwann Cells
• Form myelin sheaths around n...
3. Diagram, label and give the
functions for the parts of a typical
neuron.
Processes of Neurons
• Arm like processes extend from the cell body
of all neurons
– Bundles in the CNS= tracts
– Bundles ...
Dendrites
1. Main receptive regions
that convey incoming
information towards the
cell body
• Information moves as
graded p...
The Axon
1. Each neuron has a single axon
• Can be short or long
1. Long = nerve fiber

2. Arises from the axon hillock
• ...
The Axon, continued
• Two regions
– Conducting region
• Generates and transmits nerve impulses

– Secretory region
• At th...
The Axon, continued
• Organelles
– Contains same organelles as cell body and
dendrites
– Except NO nissil bodies and golgi...
The Axon, continued
• Movement of substances
– Anterograde-toward axon terminal
• Mitochondria, cytoskeletal elements, mem...
4. Classify neurons based on their
structure and function.
*Classification of Neurons
• Structurally
– Multipolar
– Bipolar
– unipolar

• Functionally
– Sensory (afferent)
– Motor (...
Classification of Neurons
(structurally)
1. Multipolar
• 3 + processes
• m/c; esp. in the CNS
Classification of
Neurons (structurally)
1. Bipolar
• 2 processes
1. Axon + dendrite

• Extend from
opposites sides of
the...
Classification of
Neurons (structurally)
1. Unipolar
• Single process that
divides
• Peripheral process
1. More distal
a)S...
Functional Classification
• Sensory (afferent) neurons
– Transmit impulses from sensory receptors in the
skin or internal ...
Functional Classification
• Motor (efferent) neurons
– Carry impulses away from the CNS to the effector
organs (muscles an...
Functional Classification
• Interneurons or Association neurons
– Lie b/w motor and sensory neurons in neural
pathways
– M...
5. Describe resting membrane
potential and describe how it is
created and maintained.
Resting Membrane Potential
1. Potential difference in a resting neuron
(Vr)
• (-70mV) – minus sign indicates the
cytoplasm...
Resting Membrane Potential
1. Due to differences in the ionic makeup of
the intracellular & extracellular fluids
• K+ most...
Resting Membrane Potential
1. At rest
• The membrane is impermeable to large
proteins
• Slightly permeable to Na+
• Very p...
6. Define action potential and be able
to draw and label a typical neuronal
action potential.
Action Potentials (nerve impulse)
1. The way neurons send signals over long
distances
2. Brief reversal of the membrane po...
Phases of the Action Potential
1. 1 – resting state
2. 2 – depolarization phase
3. 3 – repolarization phase
4. 4 – hyperpo...
Resting State
1. Voltage-gated channels are closed
• Only leakage channels are open
• Na+ channels have 2 gates
1. Activat...
Depolarizing Phase
1. Increase in Na+ permeability & reversal of
membrane potential
2. Na+ channels open letting Na+ into ...
Repolarizing Phase
1.Decrease in Na+ permeability
• Inactivation gates start to close

2.Increase in K+ permeability
• K+ ...
Hyperpolarization
1. K+ permeability continues
• Making the cell very negative
• Undershooting the resting potential (-70)...
7. List the events involved in the
initiation and propagation of an action
potential.
Propagation of an Action Potential
(Time = 0ms)
1. Na+ influx causes a patch of the axonal
membrane to depolarize
2. Posit...
Propagation of an Action Potential
(Time = 0ms)

Figure 11.13a
Propagation of an Action Potential
(Time = 2ms)

Figure 11.13b
Propagation of an Action Potential
(Time = 4ms)
1. The action
potential moves
away from the
stimulus
2. Where sodium
gates...
8. Define all or none response in
neurons.
Threshold
1. Not all local depolarization events produce APs
2. Must reach threshold (-55 mV)
• Outward current of K+ = in...
9. Compare absolute and relative
refractory periods.
Absolute Refractory Period
1. Time from the opening of the Na+ activation
gates until the closing of inactivation gates
2....
Absolute and Relative Refractory
Periods

Figure 11.15
Relative Refractory Period
1. The interval following the absolute
refractory period when:
•
•
•
•

Sodium gates are closed...
10. Compare rate of impulse
conduction on myelinated and
unmyelinated neurons.
Conduction Velocities of Axons
1. Conduction velocities vary widely among
neurons
2. Rate of impulse propagation is determ...
Saltatory Conduction
1. Current passes through a myelinated axon
only at the nodes of Ranvier
2. Voltage-gated Na+ channel...
Saltatory Conduction

Figure 11.16
Multiple Sclerosis (MS)
1. An autoimmune disease that mainly affects
young adults
2. Symptoms: visual disturbances,
weakne...
11. Define graded potential an give
examples of types of graded
potentials.
Graded Potentials
1. Short-lived, local changes in membrane
potential
2. Decrease in intensity with distance
3. Magnitude ...
Graded Potentials
• Receptor potential or generator potential– when
the receptor of a sensory neuron is excited by
some fo...
12. Compare graded and action
potentials.
13. Describe the structure of electrical
and chemical synapses.
The Synapse
1. Presynaptic Neuron
• Neuron conducting the impulses
• Info sender

2. Postsynaptic Neuron
• Neuron transmit...
Electrical Synapses
• Are less common than chemical synapses
• Correspond to gap junctions found in other
cell types
• Are...
Chemical Synapses
• Specialized for the release and reception of
neurotransmitters
• Typically composed of two parts:
– Ax...
14. List the events in nerve-nerve
chemical synaptic transmission.
15. Distinguish between temporal
summation and spatial summation.
Summation
• A single EPSP cannot induce an AP
– But multiple hits can increase the probability
– Adding together = summate...
Summation
• Temporal summation
– When one or more presynaptic neurons transmits
impulses in rapid bursts
• Releases NTs qu...
Summation
• IPSPs can also summate with EPSPs, canceling
each other out
• Neurons can also be facilitated
– More easily ex...
Summation

Figure 11.20
16. Describe the structure and
function of the spinal cord.
Spinal cord
• CNS tissue is enclosed within the vertebral
column from the foramen magnum to the first
Lumbar vertebrae
• P...
Spinal Cord
• Spinal nerves
– 31 pairs attach to the
cord by paired roots

• Cervical and lumbar
enlargements
– sites wher...
Spinal Cord
• Conus medullaris
– Termination of spinal cord

• Filum terminale
– fibrous extension of the
pia mater; ancho...
17. List the three meninges that
surround the brain and spinal cord and
their functions.
Meninges
• Three connective tissue membranes lie
external to the CNS—dura mater, arachnoid
mater, and pia mater
• Function...
Meninges

Figure 12.24a
Dura Mater
• Leathery, strong meninx composed of two fibrous
connective tissue layers
• The two layers separate in certain...
Dura Mater

Figure 12.25
Arachnoid Mater
• The middle meninx, which forms a loose brain
covering
• It is separated from the dura mater by the
subdu...
Arachnoid Mater

Figure 12.24a
Pia Mater
• Deep meninx composed of delicate connective
tissue that clings tightly to the brain
18. Know the three dural septa (in the
powerpoint) and where they are
located.
Dura Mater
• Leathery, strong meninx composed of two fibrous
connective tissue layers
• The two layers separate in certain...
Dura Mater

Figure 12.25
19. Know the features of CSF and its
functions.
Cerebrospinal Fluid (CSF)
• Watery solution similar in composition to blood
plasma
• Forms a liquid cushion that gives buo...
Circulation of CSF

Figure 12.26b
20. List the major regions of the brain
(functional areas i.e. cortices,
association areas, language areas)
and their func...
Functional areas of the Cerebral Cortex
• The three types of functional areas are:
– Motor areas—control voluntary movemen...
Cerebral Cortex: Motor Areas
•
•
•
•

Primary (somatic) motor cortex
Premotor cortex
Broca’s area
Frontal eye field
Primary Motor Cortex
• Located in the precentral gyrus
• Pyramidal cells whose axons make up the
corticospinal tracts
• Al...
Primary Motor
Cortex
Homunculus

Figure 12.9.1
Premotor cortex
• Located anterior to the precentral gyrus
• Controls learned, repetitious, or patterned
motor skills
• Co...
• Broca’s area

Broca’s Area

– Located inferior region of the premotor area
– Present in one hemisphere (usually the left...
Frontal Eye Field
• Frontal eye field
– Located anterior to the premotor cortex and
superior to Broca’s area
– Controls vo...
Sensory Areas
•
•
•
•

Primary somatosensory cortex
Somatosensory association cortex
Visual and auditory areas
Olfactory, ...
Sensory Areas

Figure 12.8a
Primary Somatosensory Cortex
• Located in the postcentral gyrus, this area:
– Receives information from the sensory recept...
Primary Somatosensory Cortex
Homunculus

Figure 12.9.2
Somatosensory association cortex
• Located posterior to the primary
somatosensory cortex
• Integrates sensory information
...
Visual Areas
• Primary visual (striate) cortex
– Seen on the extreme posterior tip of the occipital
lobe
– Most of it is b...
Auditory Areas
• Primary auditory cortex
– Located at the superior margin of the temporal lobe
– Receives information rela...
Others
• Olfactory Cortex (Smell)
– Medial aspect of temporal lobe
• Piriform lobe – specifically the uncus

• Gustatory c...
Association Areas
• Prefrontal cortex
• Language areas
• Visceral association area
Prefrontal Cortex
• Located in the anterior portion of the frontal
lobe
• Involved with intellect, cognition, recall, and
...
Association Areas

Figure 12.8a
Language Areas
• Located in a large area surronding the left (or
language-dominant) lateral sulcus
• Major parts and funct...
Visceral Association Area
• Located in the cortex of the insula
• Involved in conscious perception of visceral
sensations
Functional areas of cerebral cortex
• Motor areas:
– Primary motor and premotor cortices of the frontal lobe
– The frontal...
21. List the different lobes, gyri, and
sulci discussed in class and what each
separate or are associated
with.
Major Lobes, Gyri, and Sulci of the
Cerebral Hemisphere
• Deep sulci divide the hemispheres into five lobes:
– Frontal, pa...
22. Know the features of the cerebral
cortex.
Cerebral Cortex
• The cortex—superficial gray matter; accounts for
40% of the mass of the brain
• It enables sensation, co...
23. List the parts to the diencephalon
and their functions.
Diencephalon
• Central core of the forebrain
• Consists of three paired structures
– Thalamus
– Hypothalamus
– Epithalamiu...
Diencephalon

Figure 12.12
Thalamus
• Paired, egg-shaped masses that form the
superolateral walls of the third ventricle
• Connected at the midline b...
Hypothalamus
• Located below the thalamus, it caps the
brainstem and forms the inferolateral walls of the
third ventricle
...
Hypothalamic
Nuclei

Hypothalamus

Pituitary
Gland

Mammillary
body
Figure 12.13b
Hypothalamic Function
• Regulates blood pressure, rate and force of
heartbeat, digestive tract motility, rate and depth
of...
Endocrine functions of the
hypothalamus
• Releasing hormones control secretion of
homones by the anterior pituitary gland
...
Epithalamus
• Most dorsal portion of the diencephalon;
forms roof of the third ventricle
• Pineal gland—extends from the p...
Choroid
Plexus

Pineal
Gland
24. List the ventricles, their locations,
how they are connected, and the
source of cerebrospinal fluid in
them, its funct...
Ventricles of the Brain
• Lateral Ventricles (w/in hemishperes)
– Anterior separated by a septum pellucidum

• Interventri...
Ventricles
• Continuous with one another and with central
canal of spinal chord
• Hollow chambers filled with CSF and line...
Ventricles of the Brain

Figure 12.5
CSF and Choroid Plexes
– Properties of CSF slide 92.

• choroid Plexuses
– clusters of capillaries that form tissue fluid ...
Circulation of CSF

Figure 12.26b
25. Know the parts that make up the
brainstem and what cranial nerves
(CN) are associated with each
along with the functio...
Brain Stem
• Consists of three regions—midbrain, pons, and
medulla oblongata
• Similar to spinal cord but contains embedde...
Brain Stem:
Ventral View

Figure 12.15a
Brain Stem: Left Lateral View

Figure 12.15b
Brain Stem: Dorsal View

Figure 12.15c
Midbrain
• Located between the
diencephalon & the pons
• Midbrain structures include:
• Cerebral peduncles
– 2 structures ...
Midbrain Nuclei
• CN Nuclei III & IV
• Corpora quadrigemina
– 4 domelike protrusions of
the dorsal midbrain
– Superior col...
Midbrain Nuclei
• *substantia nigra
– Functionally linked to basal nuclei
– Contains melanin-precursor to dopamine
– Relat...
Midbrain Nuclei: Cross Section of
Midbrain

Figure 12.16a
Pons
• Between midbrain and the medulla oblongata
• Forms part of the anterior wall of the 4th ventricle
• Fibers of the p...
Pons

Figure 12.16b
Medulla Oblongata
• Most inferior part of the brain stem
• Along with the pons, forms the ventral wall of the
fourth ventr...
Medulla Nuclei
• Cardiovascular control center- adjusts force
and rate of heart contraction
• Respiratory centers- control...
Brain Stem:
ventral view

Figure 12.15a
26. Know the anatomy of the
cerebellum and the functions of it.
The Cerebellum

Figure 12.17b
Anatomy of the Cerebellum
• Two bilaterally symmetrical hemispheres
connected medially by the vermis
• Folia- transversely...
Cerebellar Processing
• Cerebellum recieves impulses of the intent to
initiate voluntary muscle contraction
– Propriocepto...
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
Human Anatomy and Physiology Test #5 review presentation
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Chapters 11 and 12 from Marieb 10e
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  • Microglia
  • Ependymal Cells
  • Oligodendrocytes
  • Peripheral nervous systemSatellite cellsSchwann cells
  • Dendrites- receptor region
  • Axon
  • Axolemma like sarcolema—action potential generated across
  • Multipolar
  • bipolar
  • unipolar
  • Table 11.1 comparison of structural classes of neurons
  • Table 11. comparison of structural classes of neurons
  • Resting state
  • IMPORRTANT
  • Single will not produce AP but multiple hits can
  • Replaced 3x a day every 6-8hours
  • The major relay station for 1) sensory impulses ascending to the sensory cortex, 2) inputs from subcortical motor nuclei and the cerebellum traveling to the cerebral motor cortex, and 3) impulses traveling to association cortices from lower centers
  • Is an important control center of the autonomic nervous system and a pivotal part of the limbic system it maintains water balance and regulates thirst, eating behavior, gastrointestinal activity, body temperature, and the activity of the anterior pituitary gland
  • Includes the pineal gland, which secretes the hormone melatonin
  • Circulated from lateral ventriclesinterventricularforaminathirdventriclecerebralaqueductfourthventriclemedianaperturelateralaperturessubarachnoid space
  • CSF circulation
  • The midbrain contains the corpotaquadrigemina (visual and auditory reflex centers), the red nucleus (subcortical motor centers), and the substantianigra. The eriaqueductal gray matter is involved in pain supression and contains the motor nuclei of cranial nerves III and IV. The cerebral peduncles on its ventral face house the pyramidal fiber tracts. The midbrain surrounds the cerebral aquaduct
  • Is mainly a conduction area. Its nuclei contribute to regulating respiration and cranial nerves V-VII
  • The pyramids (descending corticospinal tracts)form the ventral face of the medula oblongata. These fibers cross over (decussation of the pyramids) before entering the spinal cord. Important nuclei in the medulla regulate respiratory rythm, heart rate, and blood pressure and serve cranial nerves VII-XII. The olivary nuclei and cough sneezing, swallowing, and vomiting centers are also in the medulla
  • Human Anatomy and Physiology Test #5 review presentation

    1. 1. Test Five Review
    2. 2. 1. List and describe the characteristics of the major subdivisions of the nervous system
    3. 3. 2. List, describe and give the functions of the neuroglia found in the CNS and the PNS.
    4. 4. Neuroglia • Provide the support for neurons via glia cells • Six types – In the CNS • • • • Astrocytes Microglia Ependymal cells Oligodendrocytes – In the PNS • Satellite cells • Schwann cells
    5. 5. Astrocytes (CNS) • Most abundant, versatile & highly branched glia cells • They cling to neurons w/ their synaptic endings & cover capillaries • Function: – Support and brace neurons – Anchor neurons to their nutrient supplies – Guide migration of young neurons – Control the chemical environment
    6. 6. Microglia (CNS) 1. Small ovoid cell w/ “thorny” processes that touch nearby neurons 2. Function: • Monitor health (migrate to injured) • Transform into phagocytes when invading organisms or dead neurons are present • IMP b/c immune system cannot reach CNS
    7. 7. Ependymal Cells (CNS) 1. Range in shape from squamous to columnar 2. Line central cavities of the brain & spinal column forming a permeable barrier between cerebrospinal fluid (CSF) & tissue fluid • Help circulate CSF
    8. 8. Oligodendrocytes (CNS) 1. Produce myelin sheaths • Insulating coverings
    9. 9. Peripheral Nervous System (PNS) 1. Satellite Cells: function still unknown 2. Schwann Cells • Form myelin sheaths around nerve fibers • Vital to damage of PNS
    10. 10. 3. Diagram, label and give the functions for the parts of a typical neuron.
    11. 11. Processes of Neurons • Arm like processes extend from the cell body of all neurons – Bundles in the CNS= tracts – Bundles in the PNS= Nerves • Two types of processes: – Dendrites – Axons
    12. 12. Dendrites 1. Main receptive regions that convey incoming information towards the cell body • Information moves as graded potentials; not action potentials 2. Short, tapering, diffusely branching 3. Contain same organelles as cell body (ex. No golgi)
    13. 13. The Axon 1. Each neuron has a single axon • Can be short or long 1. Long = nerve fiber 2. Arises from the axon hillock • Extension off the cell body 3. Axon collaterals • Branching, especially at end (terminal branches) 4. Axon Terminal • Endings of terminal branches • Also called synaptic knobs
    14. 14. The Axon, continued • Two regions – Conducting region • Generates and transmits nerve impulses – Secretory region • At the axon terminals • When stimulated by the preceding nerve impulses releases neurotransmitters (can be + or -)
    15. 15. The Axon, continued • Organelles – Contains same organelles as cell body and dendrites – Except NO nissil bodies and golgi apparatus • Depends on cell body for these functions • Axolemma – Axon plasma membrane
    16. 16. The Axon, continued • Movement of substances – Anterograde-toward axon terminal • Mitochondria, cytoskeletal elements, membrane components, enzymes – Retrograde-toward cell body • Organelles being returned for destruction • Intracellular communication • Certain viruses or bacteria
    17. 17. 4. Classify neurons based on their structure and function.
    18. 18. *Classification of Neurons • Structurally – Multipolar – Bipolar – unipolar • Functionally – Sensory (afferent) – Motor (efferent) – Interneurons or association
    19. 19. Classification of Neurons (structurally) 1. Multipolar • 3 + processes • m/c; esp. in the CNS
    20. 20. Classification of Neurons (structurally) 1. Bipolar • 2 processes 1. Axon + dendrite • Extend from opposites sides of the cell body • Rare 1. Found in special senses (retina of eye/nose)
    21. 21. Classification of Neurons (structurally) 1. Unipolar • Single process that divides • Peripheral process 1. More distal a)Sensory receptors • Central process 2. Enters CNS • Called psuedounipolar b/c originally was a bipolar neuron
    22. 22. Functional Classification • Sensory (afferent) neurons – Transmit impulses from sensory receptors in the skin or internal organs toward the CNS – Most are unipolar – Cell bodies located in sensory ganglia outside the CNS – Peripheral processes can be very long
    23. 23. Functional Classification • Motor (efferent) neurons – Carry impulses away from the CNS to the effector organs (muscles and glands) – Multipolar – Cell bodies located in the CNS
    24. 24. Functional Classification • Interneurons or Association neurons – Lie b/w motor and sensory neurons in neural pathways – Multipolar – 99% of neurons in the body
    25. 25. 5. Describe resting membrane potential and describe how it is created and maintained.
    26. 26. Resting Membrane Potential 1. Potential difference in a resting neuron (Vr) • (-70mV) – minus sign indicates the cytoplasmic side (inside) is negatively charged relative to the outside • The membrane is said to be polarized • Can vary from -40 to -90 mV
    27. 27. Resting Membrane Potential 1. Due to differences in the ionic makeup of the intracellular & extracellular fluids • K+ most important role 2. Also, due to the differential permeability of the plasma membrane to those ions 3. Inside the cell • Lower conc. Na+, higher conc. K+ 4. Outside the cell • It is balanced by Cl-
    28. 28. Resting Membrane Potential 1. At rest • The membrane is impermeable to large proteins • Slightly permeable to Na+ • Very permeable to K+ & Cl• Always leaking occurring
    29. 29. 6. Define action potential and be able to draw and label a typical neuronal action potential.
    30. 30. Action Potentials (nerve impulse) 1. The way neurons send signals over long distances 2. Brief reversal of the membrane potential • -70 mV → +30 mV 3. Depolarization phase → repolarization phase → hyperpolarization phase 4. Must be stimulated to open voltage-gated channels • Graded potential → action potential 1. Location: axon hillock
    31. 31. Phases of the Action Potential 1. 1 – resting state 2. 2 – depolarization phase 3. 3 – repolarization phase 4. 4 – hyperpolarization Figure 11.12
    32. 32. Resting State 1. Voltage-gated channels are closed • Only leakage channels are open • Na+ channels have 2 gates 1. Activation gate: closed at rest 2. Inactivation gate: blocks channel when open
    33. 33. Depolarizing Phase 1. Increase in Na+ permeability & reversal of membrane potential 2. Na+ channels open letting Na+ into the cell 3. If -55 mV reached = threshold • AP starts & is cont. • Positive feedback 4. Membrane potential reaches +30 mV
    34. 34. Repolarizing Phase 1.Decrease in Na+ permeability • Inactivation gates start to close 2.Increase in K+ permeability • K+ leaves the cell
    35. 35. Hyperpolarization 1. K+ permeability continues • Making the cell very negative • Undershooting the resting potential (-70) • Sodium potassium pumps restore normal ion distribution
    36. 36. 7. List the events involved in the initiation and propagation of an action potential.
    37. 37. Propagation of an Action Potential (Time = 0ms) 1. Na+ influx causes a patch of the axonal membrane to depolarize 2. Positive ions in the axoplasm move toward the polarized (negative) portion of the membrane 3. Sodium gates are shown as closing, open, or closed
    38. 38. Propagation of an Action Potential (Time = 0ms) Figure 11.13a
    39. 39. Propagation of an Action Potential (Time = 2ms) Figure 11.13b
    40. 40. Propagation of an Action Potential (Time = 4ms) 1. The action potential moves away from the stimulus 2. Where sodium gates are closing, potassium gates are open and create a current flow Figure 11.13c
    41. 41. 8. Define all or none response in neurons.
    42. 42. Threshold 1. Not all local depolarization events produce APs 2. Must reach threshold (-55 mV) • Outward current of K+ = inward current of Na+ 3. Weak (subthreshold) stimuli potentials • are not relayed into action potentials 4. Strong (threshold) stimuli • are relayed into action potentials 5. All-or-none phenomenon – action potentials either happen completely, or not at all
    43. 43. 9. Compare absolute and relative refractory periods.
    44. 44. Absolute Refractory Period 1. Time from the opening of the Na+ activation gates until the closing of inactivation gates 2. The absolute refractory period: • Prevents the neuron from generating an action potential • Ensures that each action potential is separate • Enforces one-way transmission of nerve impulses
    45. 45. Absolute and Relative Refractory Periods Figure 11.15
    46. 46. Relative Refractory Period 1. The interval following the absolute refractory period when: • • • • Sodium gates are closed Potassium gates are open Repolarization is occurring Need a very strong stimulus to initiate an action potential
    47. 47. 10. Compare rate of impulse conduction on myelinated and unmyelinated neurons.
    48. 48. Conduction Velocities of Axons 1. Conduction velocities vary widely among neurons 2. Rate of impulse propagation is determined by: • Axon diameter – the larger the diameter, the faster the impulse • Presence of a myelin sheath – myelination dramatically increases impulse speed, prevents leakage
    49. 49. Saltatory Conduction 1. Current passes through a myelinated axon only at the nodes of Ranvier 2. Voltage-gated Na+ channels are concentrated at these nodes 3. Action potentials are triggered only at the nodes and jump from one node to the next 4. Much faster than conduction along unmyelinated axons
    50. 50. Saltatory Conduction Figure 11.16
    51. 51. Multiple Sclerosis (MS) 1. An autoimmune disease that mainly affects young adults 2. Symptoms: visual disturbances, weakness, loss of muscular control, and urinary incontinence 3. Nerve fibers are severed and myelin sheaths in the CNS become nonfunctional scleroses 4. Shunting and short-circuiting of nerve impulses occurs of
    52. 52. 11. Define graded potential an give examples of types of graded potentials.
    53. 53. Graded Potentials 1. Short-lived, local changes in membrane potential 2. Decrease in intensity with distance 3. Magnitude varies directly with the strength of the stimulus 4. Sufficiently strong graded potentials can initiate action potentials • Can be depolarization or hyperpolarization
    54. 54. Graded Potentials • Receptor potential or generator potential– when the receptor of a sensory neuron is excited by some form of energy (heat, light or other • Postsynaptic potential—when the stimulus is a neurotransmitter released by another neuron.. The neurotransmitter is released into a fluid-filled gap called a synapse and influences the neuron beyond (post) the synapse
    55. 55. 12. Compare graded and action potentials.
    56. 56. 13. Describe the structure of electrical and chemical synapses.
    57. 57. The Synapse 1. Presynaptic Neuron • Neuron conducting the impulses • Info sender 2. Postsynaptic Neuron • Neuron transmitting the electrical signal away from the synapse • Info receiver • May be another neuron or effector cell (muscle or gland)
    58. 58. Electrical Synapses • Are less common than chemical synapses • Correspond to gap junctions found in other cell types • Are important in the CNS in: – Arousal from sleep – Mental attention – Emotions and memory – Ion and water homeostasis
    59. 59. Chemical Synapses • Specialized for the release and reception of neurotransmitters • Typically composed of two parts: – Axonal terminal of the presynaptic neuron, which contains synaptic vesicles • Contain neurotransmitters – Receptor region on the dendrite(s) or soma of the postsynaptic neuron
    60. 60. 14. List the events in nerve-nerve chemical synaptic transmission.
    61. 61. 15. Distinguish between temporal summation and spatial summation.
    62. 62. Summation • A single EPSP cannot induce an AP – But multiple hits can increase the probability – Adding together = summate – Two types • Temporal summation • Spatial summation
    63. 63. Summation • Temporal summation – When one or more presynaptic neurons transmits impulses in rapid bursts • Releases NTs quickly • Spatial Summation – When the postsynaptic neurons is stimulated by a large # of terminals from the same or multiple neurons
    64. 64. Summation • IPSPs can also summate with EPSPs, canceling each other out • Neurons can also be facilitated – More easily excited by successive depolarization events b/c they are already near threshold
    65. 65. Summation Figure 11.20
    66. 66. 16. Describe the structure and function of the spinal cord.
    67. 67. Spinal cord • CNS tissue is enclosed within the vertebral column from the foramen magnum to the first Lumbar vertebrae • Provides two-way communication to and from the brain • Protected by bone, meninges, and CSF • Epidural space- space between the vertebrae and the dural sheath (dura mater) filled with fat and a network of veins
    68. 68. Spinal Cord • Spinal nerves – 31 pairs attach to the cord by paired roots • Cervical and lumbar enlargements – sites where nerves serving the upper and lower limbs emerge
    69. 69. Spinal Cord • Conus medullaris – Termination of spinal cord • Filum terminale – fibrous extension of the pia mater; anchors the spinal cord to the coccyx • Cauda equina – collection of nerve roots at the inferior end of the vertebral canal
    70. 70. 17. List the three meninges that surround the brain and spinal cord and their functions.
    71. 71. Meninges • Three connective tissue membranes lie external to the CNS—dura mater, arachnoid mater, and pia mater • Functions of the meninges – Cover and protect the CNS – Protect blood vessels and enclose venous sinuses – Contain cerebrospinal fluid (CSF) – Form partitions within the skull
    72. 72. Meninges Figure 12.24a
    73. 73. Dura Mater • Leathery, strong meninx composed of two fibrous connective tissue layers • The two layers separate in certain areas and form dural sinuses • Three dural speta extend inward and limit excessive movement of the brain – Falx cerebri—fold that dips into the longitudinal fissure – Falx cerebelli—runs along the vermis of the cerebellum – Tentorium cerebelli—horizontal dural fold extends into the transverse fissure
    74. 74. Dura Mater Figure 12.25
    75. 75. Arachnoid Mater • The middle meninx, which forms a loose brain covering • It is separated from the dura mater by the subdural space • Beneath the arachnoid is a wide subarachnoid space filled with CSF and large blood vessels • Arachnoid villi protrude superiorly and permit CSF to be absorbed into venous blood
    76. 76. Arachnoid Mater Figure 12.24a
    77. 77. Pia Mater • Deep meninx composed of delicate connective tissue that clings tightly to the brain
    78. 78. 18. Know the three dural septa (in the powerpoint) and where they are located.
    79. 79. Dura Mater • Leathery, strong meninx composed of two fibrous connective tissue layers • The two layers separate in certain areas and form dural sinuses • Three dural speta extend inward and limit excessive movement of the brain – Falx cerebri—fold that dips into the longitudinal fissure – Falx cerebelli—runs along the vermis of the cerebellum – Tentorium cerebelli—horizontal dural fold extends into the transverse fissure
    80. 80. Dura Mater Figure 12.25
    81. 81. 19. Know the features of CSF and its functions.
    82. 82. Cerebrospinal Fluid (CSF) • Watery solution similar in composition to blood plasma • Forms a liquid cushion that gives buoyancy to the CNS organs • Prevents the brain from crushing under its own weight • Protects the CNS from blows and other trauma • Nourishes the brain and carries chemical signals throughout it • Runs in subarachnoid space
    83. 83. Circulation of CSF Figure 12.26b
    84. 84. 20. List the major regions of the brain (functional areas i.e. cortices, association areas, language areas) and their functions.
    85. 85. Functional areas of the Cerebral Cortex • The three types of functional areas are: – Motor areas—control voluntary movement • Mostly anterior to central sulcus – Sensory areas—conscious awareness of sensation • Most posterior to central sulcus – Association areas—integrate diverse information
    86. 86. Cerebral Cortex: Motor Areas • • • • Primary (somatic) motor cortex Premotor cortex Broca’s area Frontal eye field
    87. 87. Primary Motor Cortex • Located in the precentral gyrus • Pyramidal cells whose axons make up the corticospinal tracts • Allows conscious control of precise, skilled, voluntary movements of skeletal muscles
    88. 88. Primary Motor Cortex Homunculus Figure 12.9.1
    89. 89. Premotor cortex • Located anterior to the precentral gyrus • Controls learned, repetitious, or patterned motor skills • Coordinates simultaneous or sequential actions • Involved in the planning of movement
    90. 90. • Broca’s area Broca’s Area – Located inferior region of the premotor area – Present in one hemisphere (usually the left) – A motor speech area that directs muscles of the tongue – Is active as one prepares to speak
    91. 91. Frontal Eye Field • Frontal eye field – Located anterior to the premotor cortex and superior to Broca’s area – Controls voluntary eye movement
    92. 92. Sensory Areas • • • • Primary somatosensory cortex Somatosensory association cortex Visual and auditory areas Olfactory, gustatory, and vestibular cortices
    93. 93. Sensory Areas Figure 12.8a
    94. 94. Primary Somatosensory Cortex • Located in the postcentral gyrus, this area: – Receives information from the sensory receptors in skin and proprioceptors in skeletal muscles, joints, tendons – Exhibits spatial discrimination
    95. 95. Primary Somatosensory Cortex Homunculus Figure 12.9.2
    96. 96. Somatosensory association cortex • Located posterior to the primary somatosensory cortex • Integrates sensory information • Forms comprehensive understanding of the stimulus (memory of objects) • Determines size, texture, and relationship of parts • Temperature, pressure, etc.
    97. 97. Visual Areas • Primary visual (striate) cortex – Seen on the extreme posterior tip of the occipital lobe – Most of it is buried in the calcarine sulcus – Receives visual information from the retinas • Visual association area – Surrounds the primary visual cortex – Interprets visual stimuli (e.g., color, form, and movement)
    98. 98. Auditory Areas • Primary auditory cortex – Located at the superior margin of the temporal lobe – Receives information related to pitch, rhythm, and loudness • Auditory association area – Located posterior to the primary auditory cortex – Stores memories of sound and permits perception of sounds – Wernicke’s area
    99. 99. Others • Olfactory Cortex (Smell) – Medial aspect of temporal lobe • Piriform lobe – specifically the uncus • Gustatory cortex (taste) – Insular lobe • Visceral Sensory area – Back part of insular lobe • Vestibular cortex – Insular and parietal cortex
    100. 100. Association Areas • Prefrontal cortex • Language areas • Visceral association area
    101. 101. Prefrontal Cortex • Located in the anterior portion of the frontal lobe • Involved with intellect, cognition, recall, and personality • Necessary for judgment, reasoning, persistence, and consciences • Closely linked to the limbic system (emotional part of the brain)
    102. 102. Association Areas Figure 12.8a
    103. 103. Language Areas • Located in a large area surronding the left (or language-dominant) lateral sulcus • Major parts and functions: – Wernicke’s area—sounding out unfamiliar words – Broca’s area—speech preparation and production – Lateral prefrontal cortex—language comprehension and word anaylysis – Lateral and ventral temporal lobe—coordinate auditory and visual aspects of language
    104. 104. Visceral Association Area • Located in the cortex of the insula • Involved in conscious perception of visceral sensations
    105. 105. Functional areas of cerebral cortex • Motor areas: – Primary motor and premotor cortices of the frontal lobe – The frontal eye field, and Broca’s area in the frontal lobe of one hemisphere (usually left) • Sensory areas – Primary somatosensory cortex and somatosensory association cortex in the parietal lobe – Visual areas in the occipital lobe – Olfactory and auditory areas in the temporal lobe – Gustatory, visceral, and vestibular areas in the insula • Association areas – Anterior association areas in the frontal lobe – Posterior and limbic association areas spanning several lobes
    106. 106. 21. List the different lobes, gyri, and sulci discussed in class and what each separate or are associated with.
    107. 107. Major Lobes, Gyri, and Sulci of the Cerebral Hemisphere • Deep sulci divide the hemispheres into five lobes: – Frontal, parietal, temporal, occipital, and insular • Central sulcus—separates the frontal and parietal lobes – The precentral and postcentral gyri border the central sulcus • Parieto-occipital sulcus—separates the parietal and occipital lobes • Lateral sulcus—separates the parietal and temporal lobes
    108. 108. 22. Know the features of the cerebral cortex.
    109. 109. Cerebral Cortex • The cortex—superficial gray matter; accounts for 40% of the mass of the brain • It enables sensation, communication, memory, understanding, and voluntary movements • Each hemisphere acts contralaterally (controls the oppisite side of the body) • Hemispheres are not equal in function • No functional area acts alone; conscious behavior involves the entire coretex
    110. 110. 23. List the parts to the diencephalon and their functions.
    111. 111. Diencephalon • Central core of the forebrain • Consists of three paired structures – Thalamus – Hypothalamus – Epithalamiums • Encloses the third ventricle
    112. 112. Diencephalon Figure 12.12
    113. 113. Thalamus • Paired, egg-shaped masses that form the superolateral walls of the third ventricle • Connected at the midline by the intermediate mass • Contains 4 groups of nuclei—anterior, ventral, dorsal, and posterior • Nuclei project and receive fibers from the cerebral cortex • *afferent impulses from all senses and all parts of the body converge on the thalamus and synapse
    114. 114. Hypothalamus • Located below the thalamus, it caps the brainstem and forms the inferolateral walls of the third ventricle • Mammillary bodies – Small, paired nuclei bulging anteriorly from the hypothalamus – Relay station for olfactory pathways • Infundibulum—stalk of the hypothalamus; connects to the pituitary gland – Main visceral control center of the body • homeostasis)
    115. 115. Hypothalamic Nuclei Hypothalamus Pituitary Gland Mammillary body Figure 12.13b
    116. 116. Hypothalamic Function • Regulates blood pressure, rate and force of heartbeat, digestive tract motility, rate and depth of breathing, and many other viceral activities • Perception of pleasure, fear, and rage – Close connection w/ limbic system • Maintains normal body temperature • Regulates feelings of hunger and satiety (satisfaction *fullness) • Regulates sleep and the sleep cycle
    117. 117. Endocrine functions of the hypothalamus • Releasing hormones control secretion of homones by the anterior pituitary gland – GH, TSH, LH, FSH, ACTH • The supraoptic and paraventricular nuclei produce ADH and oxytocin – Which is released form the posterior pituitary gland
    118. 118. Epithalamus • Most dorsal portion of the diencephalon; forms roof of the third ventricle • Pineal gland—extends from the posterior border and secretes melatonin – Melatonin—hormone involved with sleep regulation, sleep-wake cycles, and mood • Choroid plexus—a structure that helps form cerebral spinal fluid (CFS)
    119. 119. Choroid Plexus Pineal Gland
    120. 120. 24. List the ventricles, their locations, how they are connected, and the source of cerebrospinal fluid in them, its functions, how is it circulated and how frequently is it replaced.
    121. 121. Ventricles of the Brain • Lateral Ventricles (w/in hemishperes) – Anterior separated by a septum pellucidum • Interventricular foramen (lateral3rd) • Third Ventricle (w/in diencephalon) • Cerebral Aqueduct – runs through midbrain (3rd-4th) • Fourth Ventricle (w/in hindbrain dorsal to the pons)
    122. 122. Ventricles • Continuous with one another and with central canal of spinal chord • Hollow chambers filled with CSF and lined by ependymal cells
    123. 123. Ventricles of the Brain Figure 12.5
    124. 124. CSF and Choroid Plexes – Properties of CSF slide 92. • choroid Plexuses – clusters of capillaries that form tissue fluid filters, which hang from the roof of each ventricle – Have ion pumps that allow them to alter ion concentrations of the CSF – Help cleanse CSF by removing wastes
    125. 125. Circulation of CSF Figure 12.26b
    126. 126. 25. Know the parts that make up the brainstem and what cranial nerves (CN) are associated with each along with the functions of each area.
    127. 127. Brain Stem • Consists of three regions—midbrain, pons, and medulla oblongata • Similar to spinal cord but contains embedded nuclei • Controls automatic behaviors necessary for survival • Provides the pathway for tracts between higher and lower brain centers • Associated with 10 of the 12 pairs of cranial nerves
    128. 128. Brain Stem: Ventral View Figure 12.15a
    129. 129. Brain Stem: Left Lateral View Figure 12.15b
    130. 130. Brain Stem: Dorsal View Figure 12.15c
    131. 131. Midbrain • Located between the diencephalon & the pons • Midbrain structures include: • Cerebral peduncles – 2 structures that contain descending pyramidal motor tracts • Cerebral aqueduct – tube connects the 3rd & 4th ventricles • Various nuclei
    132. 132. Midbrain Nuclei • CN Nuclei III & IV • Corpora quadrigemina – 4 domelike protrusions of the dorsal midbrain – Superior colliculi • visual reflex centers – Inferior colliculi • Auditory relay • Superior cerebellar peduncles
    133. 133. Midbrain Nuclei • *substantia nigra – Functionally linked to basal nuclei – Contains melanin-precursor to dopamine – Related to Parkinson's • Red nucleus – Largest nucleus of the reticular formation; red nuclei are relay nuclei for some descending motor pathways
    134. 134. Midbrain Nuclei: Cross Section of Midbrain Figure 12.16a
    135. 135. Pons • Between midbrain and the medulla oblongata • Forms part of the anterior wall of the 4th ventricle • Fibers of the pons: – Connect higher brain centers and the spinal chord – Pontine nuclei fibers • Relay impulses between the motor cortex and the cerebellum • Middle cerebellar peduncles • Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial) • Contains nuclei of the reticular formation
    136. 136. Pons Figure 12.16b
    137. 137. Medulla Oblongata • Most inferior part of the brain stem • Along with the pons, forms the ventral wall of the fourth ventricle • Contains a choroid plexus of he fourth ventricle • Pyramids-two longitudinal ridges formed by cortiocospinal tracts • Decussation of the pyramids—crossover points of the corticospinal tracts • Cranial nerves VII, IX, X, XI, AND XII are associated with the medulla
    138. 138. Medulla Nuclei • Cardiovascular control center- adjusts force and rate of heart contraction • Respiratory centers- control rate and depth of breathing • Additional centers- regulate vomiting, hiccouping, swallowing, coughing, and sneezing
    139. 139. Brain Stem: ventral view Figure 12.15a
    140. 140. 26. Know the anatomy of the cerebellum and the functions of it.
    141. 141. The Cerebellum Figure 12.17b
    142. 142. Anatomy of the Cerebellum • Two bilaterally symmetrical hemispheres connected medially by the vermis • Folia- transversely oriented gyri • Each hemisphere has three lobes- anterior, posterior, and flocculondular • Neural arrangement- gray matter cortex, internal white matter, scattered nuclei • Arbor vitae—distinctive treelike pattern of the cerebellar white matter
    143. 143. Cerebellar Processing • Cerebellum recieves impulses of the intent to initiate voluntary muscle contraction – Proprioceptors and visual signals “inform” the cerebellum of the body’s position – Cerebellar cortex calculates the best way to perform a movement – A “blueprint” of coordinated movement is sent to the cerebral motor cortex and spinal cord neurons • Cognitive function – Recognizes and predicts sequences of events – Word association and puzzle solving
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