Chapter 15

Front 1

nervous system

Back 1

- organized constellation of cells specialized for repeated conduction of electrical signals within and between cells
- integrate signals of converging neurons, generate new signals, and modify properties of neurons based on their interactions
- vary on complexity and behavioral output
- neurons

Front 2

evolution of nervous system

Back 2

- cnidarians first animals with true tissue = nerve nets
- Platyhelminthes = nerve tracts
- echinoderms = nerve rings
- molluscan = a lot of centralization and sense organs
- humans = huge number of centralization and sense organs

Front 3

trends in evolution of nervous system

Back 3

- increase number of nerve cells
- concentration of nerve cells forming masses of nerve cell bodies (ganglia)
- increased number of interneurons and more complex synaptic connections
- specialization of function
- cephalization

Front 4

specialization of function

Back 4

- greater and greater specialization within ganglia leading to brain and spinal cord
- transmission of impulse in 1 direction = afferent - efferent - effectors

Front 5

central nervous system (CNS)

Back 5

- consists of relatively large structures such as the brain, spinal cord in which large numbers of neurons and support cells are anatomically juxtaposed and interact to achieve integrative functions
- rich with cell bodies and processes of neurons
- interneurons confined
- sensory neurons = convey information to CNS
- motor neurons = convey information out of CNS to control muscles or other effectors
- all signigicant integration and processing of neural activity
- no peripheral integration

Front 6

effector

Back 6

- organ, tissue, or cell that acts under the direction of the nervous system
- muscles and glands
- carries out functions such as motion or secretion

Front 7

peripheral nervous system (PNS)

Back 7

- nerve endings and receptors
- nerve fibers
- ganglia
- consist of all processes and cell bodies of sensory and motor neurons that are present outside CNS
- autonomic ganglia and enteric nervous system
- no sensory to motor synapses

Front 8

ganglia

Back 8

- sits outside spinal cord
- dorsal root = sensory (afferent)
- autonomic = sympathetic, parasympathetic (efferent)

Front 9

parasympathetic

Back 9

- goes inside the organs
- preganglionic and postganglionic
- always ACh and excitatory
- maintains things as status quota
- emerge from cranial region and sarcratic region
- short postganglionic and long preganglionic
- mediate rest and digest functions
- ganglia located mostly at or near the effectors
- preganglionic neurons exit from the cranial and sacral region = craniosacral division
- release ACh = cholinergic
- promote proceses that restore body reserves of energy

Front 10

sympathetic

Back 10

- ACh at preganglionic and noradrenegic at postganglionic
- short preganglionic and long postganglionic
- emerge in middle
- fight or flight = increase ability to invade
- ganglia located mostly near spinal cord
- preganglionic neurons exit in nerves of thoracic and lumbar regions of spine = thoracolumbar division
- release catecholamines = adrenergic
- promotes mobilizing body energy reserves and inhibits some processes that restore reserve

Front 11

2 divisons of PNS

Back 11

- somatic nervous system
- autonomic nervous system

Front 12

somatic nervous system

Back 12

- controls skeletal (striated) muscles that generally produce voluntary movements
- somatic effectors = skeletal muscle
- sensory reception of external stimuli and transmission of sensory
- controls muscles of locomotion and other body movements, speech, and breathing
- observable behavior
- touch, hearing, vision, taste, olfaction = sensory receptors
- motor and sensory neurons exit and enter CNS in cranial and spinal nerves
- 12 pairs of cranial nerves with specialized functions
- dorsal root ganglia = enlargements of dorsal roots outside the spinal cord
- somatic motor neurons directly synapse on muscle fibers
- somatic motor association area coordinate learned movements

Front 13

autonomic nervous system

Back 13

- controls autonomic effectors
- internal effectors = include all neuron-controlled effectors other than striated muscle
- cardiac muscle, smooth muscle, glands
- sensory neurons that convey information to CNS about internal organs
- smooth muscle
- exocrine glands = discharge secretions into environment or into internal body cavities
- few endocrine glands
- acid secreting cells of stomach
- pacemaker and other regions of the heart
- BAT
- swim bladders
- integumatory chromatophores
- sympathetic, parasympathetic, enteric

Front 14

development of nervous system

Back 14

- starts as neural tube = notocord folds in the neural plate
- specialization begins at the head

Front 15

principles of brain function

Back 15

- brain function is somewhat localized
- brains have maps
- size matters
- vertebrate brain evolution
- neural circuits are plastic

Front 16

brain function is somewhat localized

Back 16

- neural activity is measured as increased blood flow
- neurons organized in circuits so they can elicit a coordinated, adaptive response of effectors
- neurons in different regions play different functional roles
- localization of function
- function involve a circuit in brain = network of synaptically interconnected and interacting neurons

Front 17

brains have maps

Back 17

- brain maintain information about anatomical organization in terms of topographic representation
- related to specific regions having specific functions
- maps = topographic representation of body's anatomy
- somatotopic map = map of body projected to brain area
- maps aren't universal
- record and recall parameter of where stimulus occur or an effector is to be controlled

Front 18

size matters

Back 18

- more neurons = more complex integration
- larger size doesn't mean you're more intelligent
- increase in processing capabilites

Front 19

vertebrate brain evolution

Back 19

- repeated expansion of forebrain = birds and mammals have complex
- more complex = cerebral cortex
- dorsal pallium = neocortex
- elaborations of preexisting structures
- deeper structures of midbrain and hindbrain

Front 20

neural circuits are plastic

Back 20

- synapses change
- long term memory requires changes in "wiring" of brain
- synapses change with development, maturation, experience
- short-term memory can be disrupted
- long-term memory stored more permanently = changes in strengths of synaptic interconnections of neurons
- neuronal proliferation

Front 21

general functional features of nervous system

Back 21

- sensory receptor cells transform environmental stimuli into electrical signals
- central interneurons integrate signals from sensory receptors and other signals arising, generating integrated pattern of impulses
- motor commands are sent out from CNS to effectors

Front 22

2 major trends characterize evolution of nervous system

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- centralization = structural organization in which integrating neurons are collected into central integrating areas
- cephalization = concentration of nervous structures and functions at the head

Front 23

4 terms for bundles of nerve axons

Back 23

- nerve = bundle of axon in PNS
- connective = between ganglia in CNS
- tract = within ganglion
- commissure = between right and left sides of bilaterally symmetrical ganglion

Front 24

afferent

Back 24

- neurons that carry nerve impulses away from CNS
- peripheral nerves

Front 25

efferent

Back 25

- neurons that carry nerve impulses away from CNS

Front 26

CNS consist of 2 types of tissue

Back 26

- gray matter
- white matter

Front 27

gray matter

Back 27

- composed of intermingled neuronal cell bodies, processes, and synaptic contacts
- external of brain
- internal of spinal cord

Front 28

white matter

Back 28

- consists of entirely of tracts of myelinated axons which imparts white appearance
- external of spinal cord
- internal of brain

Front 29

2 types of circuits of spinal cord

Back 29

- local circuits
- ascending/descending

Front 30

local circuits

Back 30

- exist within single segments of spinal cord
- sensory neurons entering a segment control motor output

Front 31

ascending/descending

Back 31

- sensory input relayed to brain
- higher integration
- information exchanged between spinal cord and brain

Front 32

nerves in PNS that connect to CNS

Back 32

- cranial = connect to brain
- spinal = connect to spinal cord
- brain receives sensory input from sensory neurons in cranial nerves and via ascending pathways from spinal cord
- brain motor neurons travel within nerve control effectors of the head
- spinal nerves arranged segmentally
- spinal cord receives sensory input through dorsal roots of spinal nerves
- sends motor output to periphery of body via ventral roots of spinal nerves

Front 33

brain structural organization

Back 33

- 3 major regions: midbrain, forebrain, hindbrain
- 5 subdivisions:
* forebrain = tetencephalon, diencephalon
* midbrain = mesencephalon,
* hindbrain = metencephalon, myelencephalon

Front 34

hindbrain

Back 34

- connects to spinal cord

Front 35

medulla oblongata

Back 35

- ascending and descending nerve tracts
- gray matter host a variety of vital nuclei reserved for cranial nerves and sensory neurons
- connect brain with spinal cord relaying sensory info to thalamus and other parts of brain stem
- cardiovascular centers = adjusting heart rate and strength of contraction
- respiratory rhythmicity centers = set basic pace for breathing

Front 36

pons

Back 36

- situated between midbrain and medulla
- relay signals from cortex to assit in control of movement
- control of sleep and arousal

Front 37

pontine motor nuclei

Back 37

- part of pons which store memory of intention during motor activity
- modification of actions or error correction
- learning motor skills

Front 38

cerebellum

Back 38

- 2nd largest part of the brain
- important in motor corrdination
- motor neurons in spinal cord activate muscles as result of 3 inputs
- input from local spinal circuits
- descending input from brain
- sensory input
- movement of muscle provides sensory feedback

Front 39

output neuron is purkinje cell

Back 39

- for cerebellum
- between molecular and granular layer
- enormous set of dendrites
- axon carries information outside cerebellum

Front 40

climbing fibers

Back 40

- cerebellar inputs
- excitatory 1:1 synapses with purkinje cells
- may convey error signals

Front 41

mossy fibers

Back 41

- cerebellar inputs
- excitatory input to granule cells
- may convey broad info about sensory input of movement

Front 42

interneurons

Back 42

- granule cells, stellate cell, basket cell, golgi cell
- granule cells have parallel fibers in molecular layer = excitatory
- all other inhibitory and mediate different types of inhibition

Front 43

motor task learning

Back 43

- involve changes in long term depression at synapses of parallel
- involve changes in long term depression at synapses of parallel fibers onto purkinje fibers
- involves hetersynaptic interaction in which climbing fiber depresses synaptic action of parallel fiber as it synapses on purkinje cell

Front 44

midbrain

Back 44

- processes visual and auditory information
- helps maintain consciousness
- generate autonomic motor responses = reflexes
- collicuous
- motor nuclei for 2 cranial nerves
- reticular formation headquarters
- nuclei involved in maintaining muscle tone and posture
- nucleus that regulates motor output of basal ganglia = substanta nigra
- bundles of nerve fibers linking cerebrum to cerebellum and brain stem = peduncles

Front 45

colliculi

Back 45

- superior = control reflexes in response to visual stimuli
- inferior = control reflexes in response to auditory stimuli

Front 46

cerebrum

Back 46

- divided into 2 cerebral hemispheres
- superficial layer of gray matter = cerebral cortex
- conscious thought
- memory storage and processing
- sensory processing
- regulation of skeletal muscle contraction
- fissures = deep grooves
- gyri = folds
- sulci = shallow depression

Front 47

cerebral hemisphere divided into lobes

Back 47

- frontal lobe, parietal lobe, temporal lobe, occipital lobe
- fifth lobe, insula, medial to lateral sulcus

Front 48

left cerebral hemisphere

Back 48

- general interpretive and speed centers
- responsible for language based kills
- important for analytical tasks like mathematics and logic

Front 49

right cerebral hemisphere

Back 49

- analyze and interprets sensory information
- enables identification by touch, smell, sight, taste
- allows recognition of faces and 3D relationships

Front 50

corpus callosum

Back 50

- connect left and right hemisphere
- thick tract of white matter connecting 2 cerebral hemispheres
- carries about 4 billion impulses per second

Front 51

crossing over

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- sensory information from one side of body ends up on opposite side
- motor commands from one side of brain go to opposite side of body
- occurs in brain stem and spinal cord

Front 52

nuclei

Back 52

- groups of nerve cell bodies in CNS
- basal nuclei in each cerebral hemisphere
- subconscious control of muscle tone
- helping direct movements like walking and running

Front 53

primary motor cortex

Back 53

- sends voluntary commands to skeletal muscle
- neurons here = pyramidal cells - activate spinal motor neurons
- organized by body part but the different ares control organized movement rather than individual muscles
- directly activates spinal motor centers to generate movement

Front 54

pre-motor cortical region

Back 54

- complex mosaic of areas involved in planning and organizing movement
- especially of limbs and face

Front 55

cerebellum and basal ganglia

Back 55

- connected to cerebral cortex in looping circuits
- cerebellum is active in coordinating movements and in motor learning
- basal ganglia involved in initiation of movements by dis-inhibition
- parkinson's and huntington's disease originate with abnormalities here

Front 56

primary sensory cortex

Back 56

- receives general somatic sensory information
- processes sense of touch, pressure, pain, vibration, taste , temperature

Front 57

somatic sensory association area

Back 57

- monitors primary sensory cortex activity
- allows recognition of light touch

Front 58

integrative centers

Back 58

- perform complex processes and are restricted to either left or right cerebral hemisphere
- speech center of Broca's are or motor speech area = regulates pattern of breathing and vocalization for speed

Front 59

location of speech function

Back 59

- neurons in wernicke's area send axons via arcuate fasciculus to broca's area
- wernicke's area involved in understanding spoken word
- broca's area initiates grammatical speed

Front 60

basal ganglia

Back 60

- group of nuclei in brain including the striatum, pallidum, substantia nigra, and subthalamic nucleus
- active in learning, habit formation, certain psychiatric disorders
- set of nuclei or cluster of brain neurons located in forebrain and midbrain under cerebral cortex
- important in selecting movement, suppressing competing or unwanted movement areas: caudate nucleus, globus pallidus
- imporatn areas: caudate nucleus, putamen, globus palidus
- caudate nucleus and putamen = receive excitatory input from many parts of cerebral cortex
- send inhibitory neurons to globus pallidus

Front 61

indirect pathway

Back 61

- through basal ganglia neurons from cerebral cortex excite striatal neurons, which inhibit neurons in globus pallidus and pars interna

Front 62

globus pallidus neurons

Back 62

- normally inhibit neurons in thalamus that promote movement
- when globus pallidus is inhibited = thalamus is dis-inhibited and promotes movement

Front 63

long term memory

Back 63

- declarative: diencephalon, hippocampus
- procedural: amygdala, cerebellum

Front 64

limbic system

Back 64

- receives signals from neurons that either secrete serotonin or norepinephrine or form neurons that secrete both

Front 65

diencephalon

Back 65

- surronds 3rd ventricle
- chroid plexus in anterior portion
- posterior portion contain pineal gland = produces melatonin that helps regulate day-night cycle
- thalamus and hypothalamus

Front 66

thalamus

Back 66

- relay and processing center for sensory information
- composed of 2 halves separated by 3rd ventricle
- relay point and filter for sensory information
- sends some information to primary sensory cortex and rest to subconscious centers in brain
- plays role in coordinating voluntary and involuntary motor commands

Front 67

hypothalamus

Back 67

- centers for emotions, autonomic functions, hormone production
- subconscious centers involved with rage, pleasure, pain, sexual arousal
- adjusting autonomic centers in pons and medulla oblongata
- coordinating nervous and endocrine system activities
- secretion of hormones
- sensation of hunger and thirst
- coordinating voluntary and autonomic functions
- regulating normal body temperature
- coordinating daily activity cycles

Front 68

biological clock

Back 68

- endogenous physiological timing mechanism
- rhythmically modulate functioning of cells, tissues, organs
- temporal organization = timed pattern of change in physiology or behavior thats independent from change in environment
- operations of nervous system = controlling physiological and behavioral processes via nervous and neuroendocrine output
- orchestrate daily and seasonal changes
- free-running
- times pattern of physiological change
- endow an animal with an intrinsic temporal organization

Front 69

endogenous rhythms

Back 69

- output of clock
- rhythms that continue in absence of environmental information about time
- ancient feature of life
- correlate with natural history and compensate for temperature

Front 70

rhythm

Back 70

- circadian rhythm = endogenous rhythm that has a period of about a day
- in phase = two rhythms occur synchronously
- free running rhythm = biological rhythm that persists when environmental cues are absent
- entrainment = process by which biological rhythm is brought into phase with environmental rhythm
- phasing factor = environmental rhythm

Front 71

adaptive advantages of biological clocks

Back 71

- predictive = enable animal to anticipate and prepare for regular environmental changes
- feed-forward control = initiates changes in physiological systems, rather than correcting for changes after happening
- photoperiod = number of hours of daylight in a 24 hour day
- timing of processes during periods of 24 hour day when environmental cues are vague or unreliable
- changes in photoperiod
- use sun to determine compass direction

Front 72

timekeeping mechanism

Back 72

- depends on rhythmic alternation between enhanced and inhibited expression of key clock genes
- enhanced expression leads to increased levels of protein
- protein negative factor for expression = suppresses
- circadian oscillator

Front 73

suprachiasmatic nuclei

Back 73

- location of master circadian clock in hypotalamic region of diencephalon
- dorsal to optic nerve at optic chiasm
- express rhythmic circadian activity of clock genes
- ventral and dorsal (SCN) differ in NT, intrinsic rhythmicity and connections with other brain areas

Front 74

pineal gland

Back 74

- small, unpaired gland that forms embryolligaity as an evagination of roof of brain and is found in all vertebrates
- melatonin = compound synthesized from AA tryptophan
- not independently rhythmic = circadian control from SCN

Front 75

clock mechanisms based on rhythm of gene expression

Back 75

- involve oscillation of proteins in individual cell by alternating up and down regulation of clock genes
- in mouse, clock components include CLOCK and BMAL1 - regulatory targets of these factors are teh 3 period genes
- constant production of clock genes

Front 76

CLOCK and BMAL1

Back 76

- transcription factors which are able to form heterodimers and activate transcription upon binding to E-box promoter elements

Front 77

3 period genes

Back 77

- (PER) and CRY genes that function as negative regulators, block activation by CLOCK, BMAL1
- PER1, PER2, and CRY1 accumulate in nuclei of SCN neurons at end of subjective day and disappear at end of circadian night

Front 78

circadian rhythm

Back 78

- don't control
- can choose to ignore
- babies have terrible circadian rhythm = isn't fixed
- need light and dark in order for it to behave appropriately