A&P I Central Nervous System and ANS
Terms
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copy deck
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How Information is recievied
Analog vs. Digital -
Analog - is how everything comes in from the world around
Digital - how we process the world around us. It is All or None - On or Off (Action Potential) - Three overlapping functions of nervous system
-
Sensory Input - Gathered information
Integration - Process and interprets sensory input, the decides what should be done with it
Motor Output - the actual respones required after integration - (3) parts to a typical nerve
-
Cell body - inside CNS its a cell body, outside its a ganglion
dendrites -
Axons - tracts for information -
Definition of ganglion
Definition of Nuclei -
ganglion - cell body in CNS
Nuclei - cell body outside CNS - Description of a Neuron
-
High longevity - lasts a longtime
Amitotic - has no mitosis, so when it is damaged, it wont grow back
High metabolism - uses lots of ATP
Needs support cells - called neuroglia, w/o it will die - Types of Neuroglia (support cells) in CNS
-
Astrocyte
microglia
ependymal
oligodendrocyte - Neuroglia - Astrocyte
-
-helps transport nutrients in and out of neuron
-absorbs extra neurotransmitters and K+ ions
may play a role in nerve transmission - Neuroglia - Microglia
-
-macrophage like languherhans cell
-acts like immune
-cells of immune system are denied access to CNS - Neuroglia - Ependymal
-
-mostly columnar and ciliated
-circulate spinal fluid
-line inner portion of surrounding spinal cord - Neuroglia - Oligodendrocyte
-
-Same as Schwann cell, but in CNS
-Produces myelin sheath in white matter - Support cells in Parasympathetic system
-
-Satellite cells
-Schwann cell - Neuroglia (PNS)- Satellite Cells
-
-wrap around cell body
-help maintain cell body - Neuroglia (PNS)- Schwann Cell
-
-produce Schwann sheath (myelin sheath)
-produces myelin (membrane)
- wraps neuron in myelin for insulation
- speeds up process
- has outer most layer called neurolemma - Characteristics of Myelin
-
- myelin is made of fat
- myelin is non polar
- myelin is used for insulation
- outermost layer called neurolemma - Neurolemma
-
-outermost layer of myelin (Schwann) sheath
-it is nucleated and cytoplasmic
-encloses myelin sheath -
Structure of Neuron
- Dendrite -
- carry impulse to body
- has branching extensions of membranes containing cytoplasm
- same organelles as body
- graded potential
- lots of Rough Endoplasmic reticulum (nissel bodies)
-produces protiens
-tansports w/ cytoskeleton
- final destination is synaptic end bulbs
- usually not mylennated -
Structure of Neuron
- Body -
- Nucleus
- Mitochondria, Golgi, Lysosomes
- Lack centrioles
- RER (Nissl bodies)
-chromatophilic b/c they stain dark -
Structure of Neuron
- axon hillock -
- Highly excitable
- AP originates here
- transition from Graded Potential to Action Potentional
- Neural integrators count excitatory and inhibitory impulses -
Structure of Neuron
- axon -
- lead away from cell body
- collaterals
- telodendria
- synaptic knobs
- classified via structure or function -
Stucture of neuron
- axon
- collaterals - - collaterals - side branches
-
Structure of Neuron
- Axon
- Telodendria - Axon terminal branches divided into hundrends and thousands
-
Stucture of Neuron
- Axon
- Synaptic Knobs - contains neurotransmitters which are protiens and peptides
-
Stucture of neuron
- Axon
- Classification via structure -
- Multipolar - 3 or more processes (axons/dendrites)
- most common in CNS
- Bipolar - 2 processes
- dendrites converge into one before getting to axon
- found in CNS (Retina)
- unipolar - one axon opening to cell body
- w/ ganglia in periphreal nervous system
- outside CNS -
Structure of Neuron
- Axon
- classification via function -
- sensory - afferent
- all are unipolar
- w/ cellbodies outside CNS
- motor - efferent (effect)
- multipolar
- inside CNS
- Interneurons - association
- lie between sensory and motor neurons
- make up 99% of neurons in body
- most in CNS
- multipolar -
Transmission
- voltage - Potential Energy between 2 points that have different charges
-
Transmission
- potential -
- Difference between 2 charges at give voltage/electrical voltage difference across membrane
- separated charges of oppostie sign -
Transmission
- at rest -
- Resting potential = -70 mV
- -70 mV created by Disequilibrium
- Disequilibrium is created by Na+ K+ pump -
Transmission
- channels -
- voltage gated - opens w/ voltage
- only in axons
- ligand - opens in response to chemical stimulus
- only in dendrites
- Mechanical - opens in response to mechanical stimulus
- only in dendrites -
Transmission
- Graded Potental -
- Analog information
- Originates from cell body or dendrites
- different names depending on stimulus (EPSP or IPSP or others)
- is ligand or mechancial gated
- Varies in amplitude depending on strength of stimulus
- Localized - short lived, doesn't go far -
Transmission
- Action Potential -
- Voltage gated
- originates in Axon
- it is all or none - On or Off
- long lived, can travel long way
- - Interpretation of Action potential
-
* Na+ gates open
- -55 mV threshold is broken
- quick depolarization occurs
- voltage drops to 0
- at +30 mV
- Na+ gates close, K+ gates open
- called repolarization
- at -74 mV
- Hyperpolarization occurs
- Na+ K+ pump operates to restore -70 mV resting - Interpretation travels in a ...
-
Wave!!!
- travels down the axon
- known as prpagation
- carried via microtubules
- only in one direction (towards telodendria) -
Schwann cells
- other characteristics -
- have no gates
- located at Node of Ranvier
- Saltatation - wave skips from node to node
- depolarization in this way saves energy - Node of Ranvier
-
- Patches of exposed neuron
- gaps in the myelin (schwann)sheath
- information exchange takes place in these gaps -
Graded Potential
- further information -
- different names depending on location/orgin
- does not propagate itself
- very isolated signal
- IPSP - Inhibitory Post Synaptic Potential
- hyperpolarized, causes the membrane potential to be more (-)
- nerve impulse must go further to break -55 mV threshhold
- EPSP - excitatiory post synaptic potential
- depoarliezed, causing membrane potential to be less (-)
- nerve impulse has less difficulty breaking -55 mV threshold
*** view graphs*** -
Synapapse-Neurotransmitter
- Presynaptic -
- Ca2+ voltage gates open
- breaks actin
- Synaptic vesicle drops - releasing neurotransmitter -
Synapapse-Neurotransmitter
- Post synaptic -
- Differing types of Graded Potential
- temporal summation
- spatial summation -
Synapapse-Neurotransmitter
- Post synaptic
- Summation - - summation means that the greater the EPSP, the more likely the chance of breaking the -55 mV threshold
-
Synapapse-Neurotransmitter
- Post synaptic
- Temporal Summation -
when summation results from the build up of neurotransmitter released by a sungle bulb 2 or 3 times in rapid succession
bang-bang-bang-bang-bang -
Synapapse-Neurotransmitter
- Post synaptic
- Spatial Summation -
When summation results from the build up of neurotransmitters released simultaneously by several presynaptic end bulbs
BOOM!!!!!! -
Neurotransmitters
- criteria to be called one... -
- must be stored and released from presynaptic end bubls
- must cause either an EPSP or IPSP
- must be naturally removed from synaptic cleft by enzyme/diffusion/uptake (ACh-ase) -
Neurotransmitters
- (5) groups -
1 - Acetylcholine (ACh)
2 - Amino Acids
3 - Peptides
4 - Novel
5 - Biogenic Amines -
Neurotransmitters
- Acetylcholine (ACh) -
- Neuromuscular
- can be either EPSP or IPSP depending on receptors
- Cardiac IPSP
- Skeletal EPSP -
Neurotransmitters
- Amino Acids -
- Only found in CNS
- (3)specific examples
- Glycine
- Glutamate
- GABA -
Neurotransmitters
- Amino Acids
- Glycine -
- IPSP
- makes up half of the neurotransmitters in the spinal cord (other half is GABA)
- Strychnine blocks its receptors -
Neurotransmitters
- Amino Acids
- Glutamate -
- EPSP
- Important for learning and memory
- during stroke, excessive release causes neurons to be stimulated to death -
Neurotransmitters
- Amino Acids
- GABA -
- Gamma Amino Btyric Acid
- IPSP
- Common in the brain
- Valium and alcohol enhance action of GABA -
Neurotransmitters
- Peptides -
- small chains of 30 to 40 amino acids
- (3) specific examples
- Endorphins
- Substance P
- Somatostatin & Cholecystokinin -
Neurotransmitters
- Peptides
- Endorphins -
- Opiates
- pleasure
- natural pain killer -
Neurotransmitters
- Peptides
- Substance P -
- Found where there is pain
- lets body know it is experiencing pain -
Neurotransmitters
- Peptides
- Somatostatin & Cholecystokinin - - produced by tissues in the GI tract
-
Neurotransmitters
- Novel -
(3) specific examples
- ATP
- Nitric Oxide
- Carbon Monoxide -
Neurotransmitters
- Novel
- ATP -
- Adenosine tri-phosphate
- can be either EPSP or IPSP
- can be found in both CNS and PNS
- Provokes pain sensation -
Neurotransmitters
- Novel
- Carbon monoxide -
- EPSP
- Causes pain, sensitivity to pain -
Neurotransmitters
- Novel
-Nitic Oxide -
- EPSP
- causes smooth muscle to relax
- release increases stroke damage
- used to treat male impotence -
Neurotransmitters
- Biogenic Amines -
- can be EPSP Or IPSP depending on receptors
- Variations on Amino Acids
- 3 generators and their neurotransmitters
- Tryptophan ...serotonin
- Histamine ... histamine
- Tyrosine ... dopamine, epinephrine, norepinephrine -
Neurotransmitters
- Biogenic Amines
- Tryptophan -
- found in turkey
- makes serotonin
- plays a role in sleep, appetite, migraines,
- LSD blocks serotonin receptors
- too little serotonin causes depression
- prozac affects uptake, leaving serotonin in synapse longer -
Neurotransmitters
- Biogenic Amines
- Histamine -
- Cause inflamation
- helps blood to reach areas that need to heal -
Neurotransmitters
- Biogenic Amines
- Tyrosine -
- depending on enzyme, synthesizes:
- Dopamine
- Epinephrine
- Norepinephrine -
Neurotransmitters
- Biogenic Amines
- Tyrosine - Dopamine -
- makes you feel good
- Parkinson's disease has TOO LITTLE DOPAMINE
- Schizophrenic has TOO MUCH DOPAMINE
- Chlorozine and heldal bind dopamine, stopping it from working
- Amphetamines increase dopamione release
- cocaine blocks dopamine receptors -
Neurotransmitters
- Biogenic Amines
- Tyrosine - Epinephrine and Norepinephrine -
- essentially adrenaline
- made by the adrenal gland
- make you feel good
- amphetamines increase production
- antidepressants and cocaine block removal from synapse -
Receptors in Autonomic Nervous System
- (3) Types -
- Nicotinic (cholinergic receptor)
- Muscarinic (cholinergic receptor)
- Adrenergic (sensative to NE and epinephrine) -
Receptors in Autonomic Nervous System
- Nicotinic -
- ACh receptor
- stimulate EPSP
- located in plasma membrane of dendrites and cell bodies of both Sympathetic and Parasympathetic postganglion neurons
- also found in neuromuscular junction -
Receptors in Autonomic Nervous System
- Muscarinic -
- ACh receptor
- IPSP for Cardiac
- EPSP for GI tract(intestines)
- receptors located in plasma membrane of effectors of Parasympathetic postganglions
- used in cardiac, smooth, and glands -
Receptors in Autonomic Nervous System
- Adrenergic
- with (2) types -
- receptor for Norepinephrine and epinephrine
- located at most sympathetic postganglion neuorns
- alpha usually stimulates
- beta usually inhibits
- for cardiac it is an IPSP
- beta blockers block receptors for beta -
Embryonic Development
- 1st system to develop... - Nervous System
- Neural Plate
-
- Embryonic origin of all neural tissue
- site where ectoderm thickens - Neural groove
- Neural plate folds inward to form neural groove
- Neural tube
- Neural groove forms into the neural tube
- Ventricles
-
- Hollow spaces in the spinal cord and brain
- Brain has (4)
- 1st & 2nd are lateral
- 3rd & 4th are not - 4 areas of the brain that develop from the Neural tube
-
1 - Prosencephalon (forebrain)
2 - Mesencephalon (midbrain)
3 - Rhombencephalon (hindbrain)
4 - 4th ventricle -
Develop from Neural Tube
- Prosencephalon -
- forebraine
- Dicencephalon
- thalamus
- hypothalamus
- epithalamus
- 3rd ventricle -
Develop from Neural Tube
- Mesencephalon -
- Midbrain w/ tracts and nuclei
- corpora quadrigemina
- visual reflex center (superior)
- auditory reflex center (inferior)
- nuclei that produce dopamine
- called E. substantia nigra
- cerebral perduncles -
Develops from the Neural Tube
- Rhombencephalon -
- hindbrain
- 2 specfic areas
- Pons
- Medulla oblongata
- Cerebellum -
Develops from the Neural Tube
- Rhombencephalon
- Pons -
- Tracts
-Conduction tracts between higher brain & spinal cord and between Cerebellum & motor cortex
- Nuclei
- apneustic area, inhaltion, and pneumatoxic, (inhibits inhalation) -
Develops from the Neural Tube
- Rhombencephalon
- Medulla Oblongata -
- Tracts
- Decussation of pyramids
- which is the crossover for signals from left and right brain
- Nuclei
- controls heart rate, respiration, blood pressure, touch, and muscle positions -
Develops from the Neural Tube
- Rhombencephalon
- Cerebellum -
- has both white and grey matter
- 1/10th the brain mass, but 1/2 the total # of neurons
- Tracts
- arbor vitae tracks
- Nuclei
- give rise to axons to spinal cord and other brain centers
- controls balance, coordination, posture, skilled movements
- evaluates how well movements initiated by motor areas in the cerebrum are being carried out -
Areas that develop from Neural Tube
- 4th ventricle - Yup - it does
- Principle parts that develop from Neural tube
-
Cerebrum - Know tracts and Nuclei
Dicephalon (and its parts)
Cerebellum (and its parts)
Brain Stem (and its parts)
Areas that are continous with spinal cord...
- pons, midbrian, medulla oblongata - Fissure
- Deep valley in brain
- Sulcus
- Shallow valley in brain
-
Parts of Cerebrum
- Central Sulcus - - Seperates frontal and parietal lobes
-
Parts of Cerebrum
- Precentral gyrus -
- Before central sulcus (towards front of brain
- motor cortex -
Parts of Cerebrum
- Postcentral gyrus -
- after central sulcus
- sensory cortex -
Parts of Cerebrum
- Longitudinal Fissure - - cuts brain into left and right cerebral hemispheres
-
Parts of Cerebrum
- Parieto Occipto Sulcus - - separetes the parietal lobes from the occipital lobes
-
Parts of Cerebrum
- Lateral Sulcus -
- above temporal
- separates each temporal lobe from the lower portion of frontal and parietal lobes -
Parts of Cerebrum
- Transverse fissure - Separates cerebellum from cerebrum
-
Parts of Cerebrum
- Cerebral Cortex -
- outer layer of grey matter in brain
- conscious behavior,
- excutive control over nervous system
- it is highly convuluted with dendrites, cell bodies, unmylennated axons
- mostly designated for facial sensory and hand control -
Parts of Cerebral Cortex
- (5) Hemispheres -
- Frontal (1)
- Parietal (1)
- Temporal (2)
- Occipital (1)
- Insula (2 - hidden inside) -
Parts of Cerebral Cortex
- Regions -
- Motory
- Sensory
- Association -
Parts of Cerebral Cortex
- Contralateral -
- means that info on the right goes to left brain, and info on left goes to right brain
- takes place at...
- Dessucation of Pyramids in Medulla Oblongata -
Parts of Cerebral Cortex
- Motor Region (4 areas) -
- Primary motor
- before central sulcus
- called precentral gyrus
- Premotor cortex
- memory of how to do a motor skill (association)
- Frontal eyefiled
- muscle control of eye
- cranial nerves III, IV, and VI
- association
- Broca's area
- motor speech area
- leftside of frontal lobe -
Parts of Cerebral Cortex
- Sensory region (8 areas) -
- primary sensory
- Somatosensory Association Area
- Primary Auditory Cortex
- Auditory Association Area
- Primary Visual Cortex
- Visual Association Area
- Gustatory Area
- Olfactory Bulbs and Cortex -
Parts of Cerebral Cortex
- Sensory region
- Primary Sensory -
- Located in postcentral gyrus
- recieves info from receptors in skin/skeletal muscles
- identifies body region being stimulated -
Parts of Cerebral Cortex
- Sensory region
- Somatosensory Assocation Area - - Integrates and analyzes different sensory inputs
-
Parts of Cerebral Cortex
- Sensory region
- Primary Auditory Cortex - - Located in Temporal lobe
-
Parts of Cerebral Cortex
- Sensory region
- Auditory Association Area -
- Perception
- due to memories, the information actually assocaited here is different for everyone -
Parts of Cerebral Cortex
- Sensory region
- Primary Visual Cortex -
- for reception
- located in the Occipital Lobe -
Parts of Cerebral Cortex
- Sensory region
- Visual Association Area - Again - perception
-
Parts of Cerebral Cortex
- Sensory region
- Olfactory bulbs and Cortex - - sense of smell - what more do ya need
-
Parts of Cerebral Cortex
- Sensory region
- Gustatory Area -
- Taste at the tip of tongue
- located at the bottom of central sulcus - Association
- Memory - the brains ability to associate information with other areas of the brain
-
Association
- Personality - Its your mood, how you act and what you do
-
Association
- Prefrontal Cortex -
- MAIN AREA FOR ASSOCIATION
- most complicated region
- processing to form personality
- closely linked to limbic (emotions)
- Intellect
- Complex learning abilities -
Association
- Left Brain -
- concrete information
- mathematical, logic, rational tasks, performing sequential processes -
Association
- Right Brain -
- Abstract information
- Musical and artistic awareness -
Association
- Language -
- Wernicke's area
- Located in left Brain
- sounding out unfamiliar words
- translates words into thoughts
- areas on right brain add tonal inflection and emotional content -
Association
- Visceral - Interpretaion from viscera
-
White Matter
- Characteristics (3) -
- Lines of communication for brain
- take things from one area of grey matter to another
- Axons are mylennated
- (4) types of tracts
- Commissures
- Association fibers
- Projection fibers
- Fornix -
White Matter
- Types of tracts
- Commissures -
- tracts run between the (2) cerebral hemispheres (left and right)
- Corpus Callosum - largest
- it runs from Right to left and Left to Right between 2 ventricles -
White Matter
- Types of tracts
- Association Fibers - - From one area of a hemisphere to another in the same hemisphere
-
White Matter
- Types of tracts
- Projection Fibers -
- at spinal cord, they fan out
- Shape is circle
- Corona Radiata
- looks like fiber optic flashlight -
White Matter
- Types of tracts
- Fornix - - bandlike fiber tracts concerned with olfaction as well as limbic system functions
- Basal Nuclei
-
- Cluster of cell bodies in Central Nervous System
- it is the inside area of grey matter -
Basal Nuclei
- Characteristics -
- Regulates motor control
- cell bodies are packged together -
Basal Nuclei
- Anterior -
- Lentiform and Caudate
- Corpus Striatum -
Basal Nuclei
- posterior - - Amygdaloid - functionality belongs to Limbic system (emotions)
-
Basal Nuclei
- middle of brain - Located here (no shit)
- Cortex means area is located in...
- Outer Grey matter
- Diencephalon
-
- develops behind Basal Nuclei
- (3) Regions = Thalamus, Hypothalamus, Epithalamus -
Diencephalon
- Thalamus -
- GATEWAY TO CORTEX
- acts as a major sensory relay and integration center of brain -
Diencephalon
- Epithalamus -
- forms roof of 3rd Ventricle
- Pineal gland = Secretes malatonin involved with sleep-wake cycles and moods
- Choroid plexus = produces cerebral spinal fluid -
Diencephalon
- Hypothalamus -
- Neural clearing house for autonomic and emotional response
- Visceral control
- Autonomic control = respiration rate, emotions, sleep, hunger, thirst, temperature reg, sex drive, sleep/wake cycle
- ends in Infundibulum = connects to pituitary gland = releases hormones - Limbic System
-
The Emotional Brain
- its where emotions live -
Limbic System
- Fornix -
- Links limbic system regions together
- White matter -
Limbic System
- 2 important parts to emotions -
Amygdala = recognizes fearful/angry faces, assesses danger, and creates fear response
Cingulate Gyrus = helps w/ conflict resolution, expressing emotions through gestures -
Limbic System
- Amygdala and Hippocampus -
- together equal LONGTERM MEMORY
- changes new info into longterm memories -
Limbic System
- special interaction with prefrontal cortex - there is a special relationship between feelings and thoughts
- Reticular Activating System
- Activates Cerebrum to wake up brain (and person)
- Meninges
- covering of the brain & Spinal cord
- Meninges order
-
from outside in...
Skull
Duramater periosteal (not in Spinal cord)
Duramater meningeal
Arachnoid mater
Subarachoid space
Pia mater -
Meninges
- Skull - The outermost covering of the brain, it is wrapped in Periosteum
-
Meninges
- Dura Mater -
It is rough and leathery w/ 2 layers
- Periosteal =(not in spinal cord
- Meningeal = true external covering of brain
- Meningeal AKA dural sheath of spinal cord -
Meninges
- Arachoid Mater -
Located as the middle Mater
- loose covering not dipping into sulci
- it is made of fine fibers and is elastic -
Meninges
- Subarachoid Space -
- Weblike extensions attach Arachoid Mater to Pia Mater
- Contains Cerebral Spinal Fluid and the largest blood vessels serving the brain
- Arachoid Villi = Absorbs Cerebral spinal fluid into blood stream -
Meninges
- Pia Mater -
- Delicate, very sticky connective tissue
- many tiny blood vessels
- only layer to cling tightly to brain -
Blood Barrier
-use and exceptions -
- capillary endothelial cells joined by tight junctions, which is the least permeable in the body
- exceptions are the avomiting center of brain stem and hypothalamus
- not yet developed in new borns - so be careful... -
Type of Stimulus
- Mechanoreceptors - - mechanical force such as touch, pressure, vibration, stretch, itch
-
Type of Stimulus
- Thermoreceptors - - temperature changes
-
Type of Stimulus
- Photoreceptors - - light energy
-
Type of Stimulus
- Chemoreceptors - - chemicals in solution/taste, smell
-
Type of Stimulus
- nociceptors - - stimuli that results in pain
-
Type of Stimulus
- proprioceptors -
- location of stimulus
- advises brain of body movements by monitoring how much organ is stretched - Stucture of Nerve
-
Nerve is a bundle of neuron fibers
- Neuron is a nerve cell
- most nerves are mixed (both sensory and motor
- special coverings of neurons -
Structure of Neuron
- coverings -
Myelin - covers Axon
Endoneuron - surrounds myelin
perineuron- surrounds fascicle (group of axons)
Epineuron - surrounds group of fascicles and blood vessels -
Cranial Nerves
- I -
Olfactory
- purely sensory
- smell -
Cranial Nerves
- II -
Optic
- purely sensory
- vision -
Cranial Nerves
- III -
Oculomotor
- purely motor
- "eye mover" 4/6 extrinsic eye muscles
- Parasympathetic -
Cranial Nerves
- IV -
Trochlear
- purely motor
- moves one muscle of eye -
Cranial Nerves
- V -
Trigeminal
- Mixed (both sensory and motor)
- has 3 divisions = Opthalmic, maxillary, and Mandibular
- dentist numbs maxillary and mandibular
- lets you feel teeth -
Cranial Nerves
- VI -
Abducens
- Purely Motor
- moves one extrinsic muscle of eye -
Cranial Nerves
- VII -
Facial
- largest Cranial nerve
- Major Cranial nerve for face
- laughing, smiling, and anterior 2/3 of tongue (sweet & salty)
- Parasympathetic -
Cranial Nerves
- VIII -
Vestibular Cochlear
- Purely sensory
- hearing -
Cranial Nerves
- IX -
Glossopharyngeal
- Mixed (both sensory & motor)
- swallowing & latter 1/3 of tongue (bitter & sour)
- Parasympathetic -
Cranial Nerves
- X -
Vagus
- Mixed (both sensory & motor)
- only cranial nerve to extend beyond head and neck
- Parasympathetic -
Cranial Nerves
- XI -
Accessory
- Mixed (both sensory & motor)
- has 2 roots = cranial root from medulla oblongata, spinal root from c1-c5 -
Cranial Nerves
- XII -
Hypoglossal
- Mixed (both sensory and motor)
- swallowing and speech -
Levels of Motor Control
- (list them) -
From lowest to high
- segmental
- projection
- precommand -
Levels of Motor Control
- Segmental -
- lowest level
- Spinal cord circuits -
Levels of Motor Control
- Projection -
- middle level
- upper motor neurons of motor cortex and brain stem -
Levels of Motor Control
- Precommand -
- highest level
- cerebellum and nuclei - Somatic Nerves
-
Motor neuron cell bodies in CNS and axons extend in spinal nerves to skeletal muscles
- thick and heavily myelinated
- lack ganglia -
Spinal Cord
- beginning and ending -
- Continous from 4th ventricle
- has a central canal
- oval shaped
- goes through Magnum foramen
- ends at L1 or L2 vertebrae -
Spinal Cord
- Butterfly shape (meaning)
- Horns -
- White matter outside
- grey matter inside
- Posterior Horns = dorsal = sensory
- Anterior Horns = ventral = motor -
Spinal Cord
- sensory tracts
- 1st 2nd 3rd order -
- Sensory tracts ascend
- 1st order = dorsal root ganglion
- 2nd order = dorsal horn
- 3rd order = thalamus -
Spinal Cord
- motor tracts
- upper motor neurons
- lower motor neurons -
- motor tracts descend
- upper motor neurons = go from motor cortex to motor nuclei
- lower motor neurons go from anterior horns to skeletal muscles -
Spinal Cord
- Reflex centers -
Interneurons are the reflex centers
- involuntary and rapid -
Spinal Cord
- Reflex centers order of operations -
Receptor - Sensory Neuron - Integration Center - Motor Neuron - Effector
*** just like that*** -
Spinal Cord
- other names for Integration center - Integration center - AKA - Interneuron - AKA - Association Center
-
Spinal Cord
- Cauda Equina -
"Horse's tail"
- collection of nerve roots at inferior end that fan out -
Spinal Cord
- Conus Medullaris - - end of cord in tapering cone shaped struture.
-
Spinal Cord
- Spinal Tap location -
Below spinal cord, below L3 vertebrae
- b/c spinal cord ends at L1 or L2 -
Spinal Cord
- Filum terminale - Pia mater fastens cord in place
-
Spinal Nerves
- Total breakdown -
31 total spinal nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal -
Spinal Nerves
- length - They be short
-
Spinal Nerves
- ganglia - Group of cell bodies outside CNS
-
Spinal Nerves
- Dorsal root -
SENSORY - AFFERENT
- cell bodies lie outside spinal cord in dorsal root ganglion -
Spinal Nerves
- Ventral root -
MOTOR - EFFERENT
- cell bodies lie in anterior horn -
Spinal Nerves
- Rami -
Spinal nerve branches into dorsal and ventral Rami
- Mixed (both Sensory & motor) -
Spinal Nerves
- Plexus - Formed from ventral Rami
-
Spinal Nerves
- Plexus = Cervical -
- C1-C4
- Phrenic nerve is most important = sensory and motor nerves for diaphram -
Spinal Nerves
- Plexus = Brachial -
- C5-C8 + T1
- it is entire nerve supply to upper extremities, neck and shoulder muscles
- Ulna = funny bone = nerve rests against medial epicondoyle
- Radial = largest branch -
Spinal Nerves
- Plexus = Lumbar -
- L1-L4
- abdominal wall, external genitals, part of lower extremities
- Femoral = Largest nerve in body = goes through thigh, buttocks,perneum, and lower extremities -
Spinal Nerves
- Plexus = Sacral -
- L4-L5 + S1-S4
- Sciatic nerve = thickest and longest in body
- Pudendal nerve = causes erection, involuntary urination -
Spinal Nerves
- Dermatones + one exception -
area of skin innervated by the cutaneous branches of a single spinal nerve
- C1 is the only spinal nerve that does not innervate a dermatone -
Spinal Nerves
- Hilton's law - Same nerve will effect skin, muscle and joint in the same localized area
-
Spinal Nerves
- Intercostal Nerves - come from thoracic vertebrae
-
Autonomic Nervous System
- Traits -
- Mixed (both sensory and motor)
- Part of the periphreal nervous system
- Effectors are smooth muscle, cardia, and glands
- normally involuntary
- has 2 neuron chain consisting of cell body of preganglionic neuron in brain or spinal cord preganglionic axon and cell body of ganglionc neuron outside CNS postganglionic axon - (2) divisions of ANS
-
Sympathetic system
Parasympathetic system -
Sympathetic system
- diff from Para -
- accelerates body
- arises from T1-T2
- preganglionic fibers are short
- postganglionic fibers are long
- Uses ACh for preganglion, Norepinephrine for Postganglion
-Ganglion are far away from organ, but close to CNS
- FIGHT OR FLIGHT -
Parasympathetic System
- diff from Sympathetic -
- Brakes
- arises from III, VII, IX, X, S2-S4
- preganglionic fibers are long
- postganglionic fibers are short
- Ganglion are near organs, away from CNS
- used for resting and digesting -
Sympathetic system
- characteristics -
- Rage, Terror, fear
- Dilates pupil by contracting radial muscle to open eye
- relaxes bladder muscle, contracts anal sphincter
- increases heart rate
- decreases digestion rate
- increases blood pressure, affects kidneys with renin
- relaxes bonchiole to breath more
- liver changes glycogen to glucose for energy -
Parasympathetic system
- characteristics -
- slows you down
- maintains homeostasis
- contracts pupil by contracting circular muscle
- contracts bladder muscle and relaxes anal sphincter
- decreases heart rate
- increases digestion rate
- constricts bonchioles -
Similarities
- Sympathetic and parasympathetic systems -
- serve most of the same organs
- generally cause opposing effects
- all preganlions release ACh