Lecture 1: The Nervous System Flashcards
Define physiology ?
The study of normal function of living organisms
Function
Define anatomy?
The study of the body & how its parts are arranged
Structure
Wnat are the 4 main types of tissues?
Nervous tissue
Muscle tissue
Connective tissues
Epithelial tissues
Define nervous system?
A constellation of cells (neurons&glia) that are organised into functional neural circuits permit in (complex) neural control of an animals physiology & behaviour
What are the 2 divisions of the nervous system?
1.) Central nervous system: brain & spinal cord
2.) peripheral nervous system
- autonomic nervous system:involuntary ( enteric NS
- somatic nervous system: motor voluntary control
What are the 2 main types of cells?
1.) neurons: functional units of NS
2.) non-neuronal cells glia (or neuroglia): Astrocyte’s, oligodendrocytes, microglia & ependymal cells
Neurons communicate info from sensors to CNS store & integrate information, communicate commands to muscle to glands.
Gia support neurons modulate neuronal signalling insulate neuronal process: providing immunesystem
What are the 2 primary function s of neurons?
1.) rapid transmission of information from specific sources to selected targets: done via action potential
2.) the integration of information / electrical activity from many sources
StructureI anatomy of neurons?
Dendrites: receive information from other neurons “convergence”
Axon: transmits information to other neurons or non-neuronal cells ( e.gsmuscles)
Basic structure of neurons?
Cell body (soma)
Dendrites
Axon terminal
Axon
Most neurons have 1 axon but con result in many axon terminals
Do neurons have wide variety of forms?
Yes -→ morphology reflecting diff functionalities
2 neuronal types from brain:
→ purkinje cells
→ pyramidal cells
2 types of glia?
Microglia: phagocytes cells → clean up after cellular damage
Macroglia: support & modulate the functions of neurons
Are motile ( more around environment)
First & major immune defense mechanism
Define macroglia?
Support and modulate the functions of neurons
Define astrocyte?
Support function for CNS neurons, contribute to the protective blood brain barrier (bbb), regulation of neurotransmitter modulation of neuronal activity
Define oligo dendrocytes?
From myelin sheath around neuronal axons in CNS
→ each oligodendrocytes can myelinate - 40 axons
→ each Schwann cell myelinate a section - I axon
Define ependymal cells ?
Specialised epithelial cells found in fluid-filled spaces of brain ventricles & central canal of the spinalcord
Produce & circulate cerebrospinal fluid (CSF)
posses microvinli which help circulate CSF around the CNS
How does CNS develop?
From embryonic neural tube,
Anterior end of neural tube → folds & swells becoming.the major divisions of the brain.
3 expanded regions = become apparent the forebrain, midbrain & hindbrain
Remainder → (posterior end) of the tube becomes spinal cord
What are the 3 main regions of the brain?
Forebrain: (prosencaphaton): cerebral hemisphere thalamus
Midbrain: (mesencephalon) superior & inferior collicular
Hindbrain: irhombsephalon cerebellum,pons medulla
Localisation of functions in human brain?
Brocá’s area: initiates grammatical speech
What is functional magnetic resonance imaging?
Detecting the functional activity of different brain areas
Indication of neural activity as measured via changes in oxygenated blood flow
More active more blood flow to that area
what does fmri tell us ?
gives us an indication of neural activity measured through oxygenated blood flow :more active more blood flow to that area
What is grey matter ?
contains larger number of cell bodies
distributed throughout he CNS ;discrete regions (nuclei
what is a white matter ?
large number of myelinated nerve fibres/axons
what does the PNS transmit ?
signals between CNS and receptors/effectors
nerves connect CNS to various parts of the body/periphery:
PNS consists both cranial nerves-(12 )connnects PNS to brain
What is the spinal nerve?
Basic organisational pattern of the body is that of a series of segments.
31 pairs
→ cervical spinal nerve (8) [neck, shoulders arms, hands)
→thoracic
→ lumbar
→ sacral
Coccygeal
How does the cross section of the spinal cord?
Repeating pattern:
Sensory (afferent) neuron axons form the dorsal roots of each succeeding segmental nerve;
Exiting (motor) efferent neurons form the ventral roots of each succeeding segmental nerve
??? May have to reword.
Define reflexes?
A behavioural or physiological response that does not require conscious information processing: is autonomic
( involuntary reaction)
Spinal reflexes: convert afferrent input → efferent output without brain centres.
What is monosynoptic?
2 neurons involved
What is poly synaptic?
More then 3 neurons
what does the efferent(motor) division of the PNS consist of ?
somatic (motor) nervous system-efferent intervention to skeletal( voluntary control )
controlling muscles of locomotion-movement, speech, breathing-sensory also
ANS-efferent innervation to tissues other than skeletal muscle (largely involuntary )
Difference between the SNS and ANS between CNS and effector?
the no of neurons
SNS: 1 neuron connects CNS directly with effector muscle
ANS:2 neurons connect the CNS to effector target
1st-preganglionic neuron and 2nd:postganglionic neuron
What are the 3 anatomically and functionally distinct parts ?
Sympathetic: Fight/flight
Parasympathetic: Rest/digest
—>these 2 have antagonistic effects in muscles, glands etc.
Enteric : autonomous nervous system (ENS)
second brain :2 nervous plexuses involved in gastrointestinal activity
Myenteric plexus :regulates motor activity
Submucosal plexus: regulates secretomotor activity
slide 43 / lecture 1
slide 45 ?
define preganglionic neurons ?
define postganglionic neuron ?
what is the function of the adrenal medulla ganglion ?
autonomic ganglion of sympathetic division
what is a noradrenergic neurons ?
preganglionic and postganglionic
what are the neurotransmitters of sympathetic and parasympathetic respectively ?
-sympa ¶ PREGANGLIONIC = both CHOLINERGIC –>use Acetylcholine
- sympa POSTGANGLIONIC =mostly ADRENERGIC —>use noradrenaline/Norepinephrine
some use ACH:innervating nerve glands
some release co-transmitters (ATP,dopamine,neuropeptides)
-Para POSTGANGLIONIC= CHOLINERGIC use ACh
some use NA
How does Ach act on postganglionic neurons ?
ACH acts on nictinic gated Ach receptors on post ganglionic neurons in automatic ganglia
-ligand gated ion channels ;when Ach binds ,channels open allowing influx of Na+ and K+ ions
eliciting fast changes in the membrane electric potential
How can sympathetic & parasympathetic divisions be distinguished?
1.) anatomy organisation
2.) neurotransmitter
3.) actions (downstreams)
What is antagonist control of involuntary functions ?
Heart rate
Blood flow
Respiration
Digestive activities
I
What is the main division of the ans?
The ens → capable of sustaining the motility of GI tract in absence of input from the CNS
Contains rich, local interconnections between efferent & efferent & interneurons found in gut -wall.
Responds to stretch & chemical compositions
