Han 200 Midterm 3

Front 1

Sensory Input

Back 1

Information gathered by sensory receptors about internal and external changes

Front 2

Integration

Back 2

Interpretation of sensory input

Front 3

Motor Output

Back 3

Activation of effector organs (muscles and glands) produces a response

Front 4

Central Nervous System

Back 4

Brain and Spinal Cord
Integration and command center

Front 5

Peripheral Nervous System

Back 5

Paired spinal and cranial nerves carry messages to and from the CNS
Sensory (afferent) division
Motor (efferent) division

Front 6

Sensory (afferent) division

Back 6

Somatic (pertaining to body) afferent fibers convey impulses from skin, skeletal muscles, and joints
Visceral (organs of body) afferent fibers convey impulses from visceral organs

Front 7

Motor (efferent) division

Back 7

Transmits impulses from the CNS to effector organs

Front 8

Motor Division of PNS

Back 8

Somatic (voluntary) nervous system
Autonomic (involuntary) nervous system (ANS)

Front 9

Somatic (voluntary) nervous system

Back 9

conscious control of skeletal muscles

Front 10

Autonomic (involuntary) nervous system (ANS)

Back 10

Visceral motor nerve fibers
Regulates smooth muscle, cardiac muscle, and glands
2 functional subdivisions - Sympathetic, Parasympathetic

Front 11

2 Principle cell types

Back 11

Neuron, Neuroglia (glial cells) - supporting cells

Front 12

Neurons

Back 12

Excitable cells that transmit electrical signals

Front 13

Neuroglia

Back 13

Astrocytes (CNS), Microglial (CNS), Ependymal (CNS) moves CSF, Oligodendrocytes (CNS) - produces myelin, Schwann cells (PNS) - produces myelin, Satellite (PNS)

Front 14

Schwann Cells

Back 14

Surround peripheral nerve fibers and form myelin sheaths
Vital to regeneration of damaged peripheral nerve fibers

Front 15

Nerve cell body

Back 15

Biosynthetic center of a neuron
Spherical nucleus with a nucleolus
Well developed Golgi apparatus
Rough ER
Network of neurofibrils
Axon hillock
Clusters of cell bodies are called nuclei in CNS, ganglia in PNS

Front 16

Nerve Cell Processes

Back 16

Dendrites and Axons
Processes are called Tracts in CNS, Nerves in the PNS

Front 17

Axon: Functions

Back 17

Conducting region of a neuron
Generates and transmits nerve impulses (action potentials) away from the cell body
Molecules and organelles are moved along axons by motor molecules in two directions: Anterograde - toward axonal terminal, Retrograde - toward the cell body

Front 18

White Matter

Back 18

Dense collections of myelinated fibers

Front 19

Gray Matter

Back 19

Mostly neuron cell bodies and unmyelinated fibers

Front 20

Resting Membrane Potential

Back 20

Potential difference across the membrane of a resting cell (cytoplasmic side of membrane is negatively charged relative to outside)
Generated by: Differences in ionic makeup of ICF and ECF, Differential permeability of the plasma membrane
Differences in Ionic Make up - ICF lower concentration of Na and Cl than ECF, ICF higher concentration of K and negatively charged proteins than ECF

Front 21

Membrane Potentials that Act as Signals

Back 21

- Membrane potential changes when concentrations of ions across the membrane change, permeability of membrane to ion changes
- Changes in membrane potential are signals used to receive, integrate and send information
- Graded Potentials
- Action Potentials

Front 22

Graded potentials

Back 22

Incoming short-distance signals

Front 23

Action potentials

Back 23

Long-distance signals of axons

Front 24

Depolarization

Back 24

- A reduction in membrane potential (toward zero)
- Inside of the membrane becomes LESS negative than the resting potential
- Increases the probability of producing a nerve impulse

Front 25

Hyperpolarization

Back 25

- An increase in membrane potential (away from zero)
- Inside of the membrane becomes MORE negative than the resting potential
- Reduces the probability of producing a nerve impulse
- Some K channels remain open allowing excessive K efflux
- This causes after-hyperpolarization of the membrane (undershoot)

Front 26

Graded Potentials

Back 26

- Short-lived, localized changes in membrane potential
- Depolarizations or Hyperpolarizations
- Graded potential spreads as local currents change the membrane potential of adjacent regions

Front 27

Action Potential

Back 27

- Brief reversal of membrane potential
- Occurs in muscle cells and axons of neurons
- Does NOT decrease in magnitude over distance
- Principal means of long-distance neural
communication

Front 28

Resting state

Back 28

- Only leakage channels for Na and K are open
- All gated Na and K channels are closed

Front 29

Depolarizing Phase

Back 29

- Depolarizing local currents open voltage-gated Na channels
- Na influx causes more depolarization
- At threshold positive feedback leads to opening of all Na channels and reversal of membrane polarity

Front 30

Repolarizing Phase

Back 30

- Na channel slow inactivation gates close
- Membrane permeability to Na declines to resting levels
- Slow voltage-sensitive K gates open
- K exits the cell and internal negativity is restored

Front 31

Role of the Sodium-Potassium Pump

Back 31

- Repolarization
- Ionic distribution back to resting conditions is restored by the thousands of sodium potassium pumps

Front 32

Repolarization

Back 32

- Restores the resting electrical conditions of the neuron
- Does NOT restore the resting ionic conditions

Front 33

Threshold

Back 33

- Membrane is depolarized
- Na permeability increases
- Na influx exceeds K efflux
- Positive feedback cycle begins
- Subthreshold stimulus (weak depolarization that does not reach threshold)
- Threshold stimulus - strong enough to push the membrane potential toward and beyond threshold
- AP is an all or none phenomenon - Action Potential happens or does not happen

Front 34

Absolute Refractory Period

Back 34

- Time from the opening of the Na channels until the resting of the channels
- Ensures that each AP is an all or non event
- Enforces one-way transmission of nerve impulses

Front 35

Relative Refractory Period

Back 35

- Follows the absolute refractory period
- most Na return to resting state
- some k channels are still open
- repolarization is occurring
- Threshold for AP generation is elevated
- Exceptionally strong stimulus may generate an AP

Front 36

Multiple Sclerosis (MS)

Back 36

An autoimmune disease that mainly affects young adults

Front 37

Sypanse

Back 37

- A junction that mediates information transfer from one neuron to another or to an effector cell
- Presynaptic neuron
- Postsynaptic neuron

Front 38

Presynaptic neuron

Back 38

Conducts impulses toward the synapse

Front 39

Postsynaptic neuron

Back 39

Transmit impulses away from the synapse

Front 40

Chemical Synapses

Back 40

- Specialized for the release and reception of neurotransmitters
- Typically composed of two parts
- Axon terminal of the presynaptic neuron (include synaptic vesicles)
- Receptor region of the postsynaptic neuron

Front 41

Synaptic Cleft

Back 41

- Fluid filled space separating the presynaptic and postsynaptic neurons
- Prevents nerve impulses from directly passing from one neuron to the next

Front 42

Transmission across the Synaptic Cleft

Back 42

- Chemical event
- Involves release, diffusion, and binding of neurotransmitters
- Ensures unidirectional communication between neurons

Front 43

Termination of Neurotransmitter Effects

Back 43

- Within a few milliseconds, the neurotransmitter effect is terminated
- degradation by enzymes
- reuptake by astrocytes or axon terminal
- diffusion away from the synaptic cleft

Front 44

Postsynaptic Potentials

Back 44

- Graded potentials
- Strength determined by amount of neurotransmitter released, time the transmitter is in the area
- EPSP - excitatory postsynaptic potentials
- IPSP - inhibitory postsynaptic potentials

Front 45

Excitatory Synapses and EPSPs

Back 45

- Neurotransmitter binds to and opens chemically gated channels that allow simultaneous flow of Na and K in opposite directions
- Na influx is greater than K efflex, causing net depolarization
- ESPS helps trigger AP at axon hillock if EPSP is of threshold strength and opens the voltage gated channels

Front 46

Inhibitory Synapses and IPSP

Back 46

- Neurotransmitter binds to and opens channels for K and Cl
- Causes a hyperpolarization
- Reduces the postsynaptic neuron's ability to produce an action potential

Front 47

Integration: Synaptic Potentiation

Back 47

- Repeated use increases the efficiency of neurotransmission
- Ca concentration increases in presynaptic terminal and postsynaptic neuron
- Brief high-frequency stimulation partially depolarizes the postsynaptic neuron

Front 48

Neurotransmitters (Language of the NS)

Back 48

- Most neurons make two or more neurotransmitters which are released at different stimulation frequencies
- 50 or more neurotransmitters have been identified
- Classified by chemical structure and by function

Front 49

Acetylcholine (Ach)

Back 49

- Released at neuromuscular junctions and some ANS neurons
- Synthesized by enzyme choline acetyltransferase
- Degraded by the enzyme acetycholinesterase

Front 50

Botulinum toxin

Back 50

- Toxin gets into axon terminals and prevents the vescicles from releasing Ach

Front 51

Nerve Gas

Back 51

Inhibits the enzyme acetylcholinesterase which breaks down Ach in the synapse.
Ach stays in receptors

Front 52

Chemical Class of Neurotransmitters

Back 52

- Biogenic amines include:
- Catecholamines
- Indolamines
- Broadly distributed in the brain
- Play roles in emotional behaviors and the biological clock

Front 53

Catecholamines

Back 53

(Dopamine, Norepinephrine, and
epinphrine.

Front 54

Indolamines

Back 54

- serotonin and histamine

Front 55

Dopamine

Back 55

- Brain - pleasure when engaged in behavior necessary for food/reproduction
- Drugs of abuse: Cocaine/Crack
- blocks re update of dopamine
- allow body to have longer effect
- produce depression and addition, body stops producing

Front 56

Functional Classifications of Neurotransmitters

Back 56

- Neurotransmitter effects may be excitatory (depolarizing) and/or inhibitory (hyperpolarizing)
- Determined by the receptor type of the postsynaptic neuron
- Acetylcholine
- Excitatory at neuromuscular junctions in skeletal muscle
- Inhibitory in cardiac muscle

Front 57

Adult brain regions

Back 57

- Cerebral hemispheres
- Diencephalon (thalamus, hypothalmus, epitalmus)
- Brain Stem (midbrain, pons, and medulla)
- Cerebellum

Front 58

Spinal Cord

Back 58

- Central cavity surrounded by a gray matter core
- External white matter composed of myelinated fiber tracts

Front 59

Brain

Back 59

- Central cavity surrounded by a gray matter core with additional areas of gray matter
- Nuclei in cerebellum and cerebrum
- Cortex of cerebellum and cerebrum

Front 60

Ventricles of the Brain

Back 60

- Connected to one another and to the central canal of the spinal cord
- Lined by ependymal cells
- Contain cerebrospinal fluid
- two C-shaped lateral ventricles in the cerebral hemispheres
- third ventricle in the diencephalon
- fourth ventricle in the hindbrain

Front 61

Cerebral Hemispheres

Back 61

- (cortex, cerebral white matter)
- Surface markings
- Five lobes per hemisphere
- Frontal
- Parietal
- Temporal
- Occipital
- Insula

Front 62

Diencephalon

Back 62

(thalamus, hypothalmus, epitalmus)

Front 63

Brain Stem

Back 63

(midbrain, pons, and medulla)

Front 64

Surface Markings

Back 64

- ridges, shallow grooves, and deep grooves
- Central Sulcus
- Longitudinal Fissure
- Transverse cerebral fissure

Front 65

Central Sulcus

Back 65

Separates the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe

Front 66

Longitudinal fissure

Back 66

Separates the two hemispheres

Front 67

Transverse cerebral fissure

Back 67

Separates the cerebrum and the cerebellum

Front 68

Cerebral Cortex

Back 68

- Thin superficial layer of gray matter
- 40% mass of brain
- Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication
- Each hemisphere connects to contralateral side of the body
- There is lateralization (specialization of cortical function in the hemispheres

Front 69

Functional areas of the cerebral cortex

Back 69

Motor areas
Sensory Areas
Association areas
Conscious behavior involves the entire cortex

Front 70

Motor areas

Back 70

- Control voluntary movement
- Primary (somatic) motor cortex
- Premotor Cortex
- Broca's Area

Front 71

Sensory areas

Back 71

- Conscious awareness of sensation

Front 72

Association areas

Back 72

integrate diverse information

Front 73

Primary (somatic) motor cortex

Back 73

Pyramidal cells -> pyramidal tracts
Motor homunculus - caricature of "little man"

Front 74

Premotor cortex

Back 74

Plans movements, coordinates movements of several groups into complex tasks (musical instrument)

Front 75

Broca's Area

Back 75

Motor speech area (left hemisphere)

Front 76

Sensory Areas

Back 76

- Primary somatosensory cortex - somatosensory homunculus
- Association areas - understanding of sensory info
- Visual Area
- Auditory areas
- Visceral sensory area
- Vestibular cortex - equilibrium

Front 77

Visual Areas

Back 77

- Primary visual (striate) cortex
- Visual Association area

Front 78

Primary visual (striate) cortex

Back 78

- Extreme posterior tip of the occipital lobe
- Receives visual information from the retinas

Front 79

Visual Association Area

Back 79

- Uses past visual experiences to interpret visual stimuli
- Complex processing involves entire posterior half of the hemispheres
- Recognizes faces and familiar objects

Front 80

Auditory Areas

Back 80

- Primary Auditory cortex
- Auditory Association Area

Front 81

Primary Auditory Cortex

Back 81

- Superior margin of the temporal lobes
- Interrupts information from inner ear as pitch, loudness, and location

Front 82

Auditory Association Area

Back 82

- Located posterior to the primary auditory cortex
- Stores memories of sounds and permits perception of sounds (car brakes, voices)

Front 83

Olfactory Cortex

Back 83

- Medial aspect of temporal lobes (in piriform lobes)
- Part of the primitive rhinecephalon, along with the olfactory bulbs and tracts
- remainder of rhinecephalon is part of limbic system ( memory/emotion)
- Region of conscious awareness of odors

Front 84

Visual Sensory Area

Back 84

- Posterior to gustatory cortex
- Conscious perception of visceral sensations (upset stomach or full bladder)

Front 85

Anterior Association Area (Prefrontal Cortex)

Back 85

- Most complicated cortical region
- Involved with intellect, cognition, recall, and personality
- Contains working memory needed for judgment, reasoning, persistence, and conscious
- Develops slowly in children, depends on feedback from social environment
- Lesions in this area can cause personality changes

Front 86

Posterior Association Area

Back 86

- Large region in temporal, parietal, and occipital lobes
- Plays a role in recognizing patterns and faces and localizing us in space
- Involved in understanding written and spoken language (Wernicke's area - receptive aphasia)
- Lesions in this area can cause neglect

Front 87

Lateralization of Cortical Function

Back 87

- Lateralization
- Cerebral dominance

Front 88

Lateralization

Back 88

- Division of labor between hemispheres

Front 89

Cerebral dominance

Back 89

- Designates the hemisphere dominant for language (left hemisphere in 90% of people)
- Most individuals with left cerebral dominance are right handed

Front 90

Lateralization of Cortical Function

Back 90

- Left Hemisphere (controls language, math, and logic)
- Right Hemisphere (Insight, visual-spatial skills, intuition, and artistic skills)
- Left and right hemispheres communicate via fiber tracts in the cerebral white matter

Front 91

Cerebral White Matter

Back 91

- Myelinated fibers and their tracts
- Responsible for communication

Front 92

Commissures

Back 92

- Connect gray matter of the two hemispheres

Front 93

Association fibers

Back 93

- Connect different parts of the same hemisphere

Front 94

Projection fibers (corona radiata)

Back 94

- Connect the hemispheres with lower brain or spinal cord

Front 95

Basal Nuclei (Ganglia)

Back 95

- Subcoritical nuclei
- Functionally associated with the subthalamic nuclei (diencephalon) and the substantia nigra (midbrain)

Front 96

Functions of Basal Nuclei

Back 96

- Influence muscular control
- Help regulate attention and recognition
- Regulate intensity of slow or stereotyped movements
- Inhibit antagonistic and unnecessary movements

Front 97

Diecephalon

Back 97

- Thalamus
- Hypothalamus
- Epithalamus

Front 98

Thalamic (inner room) Function

Back 98

- Gateway to the cerebral cortex - relay station
- Sorts, edits, and relays information
- afferent impulses from all senses and parts of the body
- impulses from the hypothalamus for regulation of emotion and visceral function
- impulses from the cerebellum and basal nuclei to help direct the motor cortices
- Mediates sensation, motor activities, cortical arousal, learning, and memory

Front 99

Hypothalamic Function

Back 99

- Autonomic control center for many visceral functions
- Center for emotional response
- Fearful person - has a pounding heart, high blood pressure, sweating, dry mouth

Front 100

Hypothalamic Function

Back 100

- Regulates body temperature, food intake, water balance, and thirst
- Regulates sleep and the sleep cycle
- Controls release of hormones by the anterior pituitary
- Produces posterior pituitary hormones

Front 101

Epithalamus

Back 101

- Most dorsal portion of the diencephalon; forms roof of the third ventricle
- Pineal gland - extends from the posterior border and secretes melatonin

Front 102

Melatonin

Back 102

Helps regulate sleep-wake cycles

Front 103

Brain stem

Back 103

- Midbrain - Substantia nigra (parkinson's disease)
- Pons - "Bridge"
- Medulla Oblongata - joins spiral cord at foramen
- Similar structure to spinal cord but contains embedded nuclei
- Controls automatic behaviors necessary for survival
- Contains fiber tracts connecting higher and lower neural centers
- Associated with 10-12 pairs of cranial nerves

Front 104

Substantia Nigra (Midbrain)

Back 104

- Functionally linked to Basal Ganglia
- Produces neurotransmitter Dopamine
- Degeneration of these Dopamine releasing neurons causes Parkinson's Disease

Front 105

Medulla Oblongata

Back 105

- Autonomic reflex centers
- Cardiovascular center
- Respiratory centers

Front 106

Cerebellum

Back 106

- 11% of brain mass, "cauliflower"
- Subconsciously provides precise timing and appropiate patterns of skeletal muscle contraction
- Tests: balance, coordination, finger-nose

Front 107

Cerebellar Peduncles (tracts)

Back 107

- All fibers in the cerebellum are ipsilateral
- Superior peduncles connect the cerebellum to the midbrain
- Middle peduncles connect the pons to the cerebellum
- Inferior peduncles connect the medulla to the cerebellum

Front 108

Functional Brain Systems

Back 108

Network of neurons that work together and span wide areas of the brain

Front 109

Limbic system (emotional brain)

Back 109

- Emotional or affective brain
- Puts emotional responses to odors
- Odors recall memories
- Limbic system interacts with the prefrontal lobes (cognitive brain)
- Hippocampus and amygdala play a role in memory

Front 110

Reticular Activating System (RAS)

Back 110

- Sends impulses to the cerebral cortex to keep it conscious and alert
- Filters out repetitive and weak stimuli. Allows unusual or significant info in
- RAS inhibited by sleep centers
- Severe injury results in permanent unconsciousness (coma)

Front 111

Electroencephalogram (EEG)

Back 111

- Records electrical activity that accompanies brain function
- Measures electrical potential differences between various cortical areas

Front 112

Brain Waves

Back 112

- Change with age, sensory stimuli, brain disease, and the chemical state of body
- EEGs used to diagnose and localize brain lesions, tumors, infarcts, infections, abscesses, and epileptic lesions
- A flat EEG is evidence of death

Front 113

Sleep

Back 113

- Unconscious but can be awake from stimulation
- Monitors environment
- Nonrapid eye movement (NREM)
- Rapid eye movement (REM)

Front 114

Importance of Sleep

Back 114

- slow wave sleep (NREM stage 3 and 4) is restorative stage
- People deprived of REM can be moody and depressed
- REM sleep can be reverse learning process as information comes from brain
- Daily sleep requirements decline with age
- Stage 4 sleep declines steadily and may disappear after 60

Front 115

Language

Back 115

- Language implementation system
- Corresponding areas on the right side are involved with nonverbal language components

Front 116

Language implementation system

Back 116

- Basal nuclei
- Broca's area and Wernicke's area
- Analyzes incoming word sounds
- Produces outgoing word sounds and grammatical structures

Front 117

Memory

Back 117

- Storage and retrieval of information
- Two stages of storage
- Short-term memory (STM, or working memory) - temporary holding of information; limited to seven or eight pieces of information
- Long-term memory (LTM) has limitless capacity

Front 118

Factors that affect transfer from STM to LTM

Back 118

- Emotional state
- Rehearsal
- Association
- Automatic memory

Front 119

Categories of Memory

Back 119

- Declarative memory (Ach) (names, dates)
- Sensory input > Assoc Cortex > Hippocampus > Prefrontal cortex
- Procedural memory (Dopamine) (instrument, riding a bike)
- Sensory and motor input > Basal Ganglia > Premotor cortex

Front 120

Protection of the Brain

Back 120

- Bone (skull)
- Membranes (meninges)
- Watery cushion (cerebrospinal fluid)
- Blood-brain barrier (filters toxins but not alcohol)

Front 121

Meninges

Back 121

- Cover and protect the CNS
- Protect blood vessels and enclose venous sinuses
- Contain cerebrospinal fluid (CSF)
- Form partitions in the skull

Front 122

Three layers of Meninges

Back 122

- Dura mater (tough mother) 2 layers of fibrous connective tissue
- Arachnoid mater (spider) subarchnoid contains CSF and blood vessels
- Pia mater (gentle mother) delicate CT, clings to brain like saran wrap

Front 123

Cerebrospinal Fluid (CSF)

Back 123

- Composition
- Watery solution
- Less protein and different concentrations than plasma
- Functions
- floats the brain
- protects the CNS from blows and other trauma
- Nourishes the brain and carries chemical signals

Front 124

Choroid Plexus

Back 124

Hangs from the roof of ventricles, produces CSF

Front 125

Spinal Cord

Back 125

- Location
- Begins at the foramen magnum
- Ends as conus medullaris at L1 vertebra
- Functions
- Provides two-way communication to and from the brain
- Contains spinal reflex centers

Front 126

Spinal Cord Protection

Back 126

- Denticulate ligaments: extensions of pia mater that secure cord to dura mater
- Filum terminale: fibrous extension from conus medullaris; anchors the spinal cord to the coccyx
- Bone, meninges, and CSF
- Cushions of fat and network of veins in the epidural space between the vertebrae and spinal dura mater
- CSF in subarchnoid space

Front 127

Gray Matter

Back 127

- Dorsal Horns - interneurons that receive somatic and visceral sensory input
- Ventral Horns - Somatic motor neurons whose axons exit the cord via ventral roots
- Lateral Horns (only in thoracic and lumbar regions) - sympathetic neurons
- Dorsal Root (spinal) gangia - contain bodies of sensory neurons

Front 128

White Matter

Back 128

- Consists mostly of sensory and motor tracts
- Transverse tracts cross from one side to the other
- Tracts are located in three white columns (dorsal, lateral, ventral)
- Each spinal tract is composed of axons with similar functions

Front 129

Ascending pathways

Back 129

- Two pathways transmit somatosensory information to the sensory cortex via the thalamus
- Dorsal column-medial lemniscal pathways
- Spinothalamic pathways
- Spinocerebellar tracts terminate in the cerebellum