4. Cells of the Nervous System I Flashcards
TRANSMISSION of information by which nerve type
AFFERENTS
RESPONSE by which nerve type
EFFERENT
RECEPTORS in the SKIN that pick up SENSATION / STIMULI:
- MEISSNER CORPUSCLE
- PACINIAN CORPUSCLE
- RUFFINI CORPUSCLE
- HAIR FOLLICLE
- MERKEL COMPLEX
- FREE NERVE ENDINGS
which RECEPTORS detect PRESSURE
MERKEL disks
which RECEPTORS detect VIBRATION
PACINIAN CORPUSCLE
which RECEPTORS detect TEMPERATURE
FREE NERVE ENDINGS
which RECEPTORS detect MOVEMENT
HAIR FOLLICLE & MEISSNER CORPUSCLE
which RECEPTORS detect STRETCH of Skin
RUFFINI CORPUSCLE
which RECEPTORS are UNENCAPSULATED
HAIR FOLLICLES & FREE NERVE ENDINGS
which RECEPTORS detect PAIN
FREE NERVE ENDINGS
GREAT DIVERSITY between all nerve cells
common features:
ELONGATED
HIGHLY BRANCHED
etc
TYPES of NEURONS
MULTIPOLAR
BIPOLAR
PSUEDO-UNIPOLAR
UNIPOLAR
what do CELL BODIES of NEURONES (the SOMA) produce
NEUROTRANSMITTER & ENERGY
contains Nucleus with DNA and lots of Mitochondria
What is a DENDRITE
small structures that RECIEVE INPUTS from Axons of Other Neurones
- interact and communicate with other neurons
what are the MAIN GLIAL CELLS of the PERIPHERAL NERVOUS SYSTEM
SCHWANN CELLS
- may be Myelinated schwann cells
SCHWANN CELLS carry out many roles including…
- Physically Supporting neurone
- Phagocytosis of dead/dying cells around it
- Antigen Presenting if infection
- sucks up some of Neurotransmitter
Other PNS GLIAL CELLS and their ROLES:
- SATELLITE GLIAL CELLS
support - ENTERIC GLIAL CELLS
line blood vessels of the gut (filled with bacteria) to form a barrier so bacteria doesn’t enter blood vessels - OLFACTORY ENSHEATHING CELLS
schwann cells for the olfactory nerve
what is BETWEEN MYELIN SHEATH to INCREASE SPEED of transmissions
NODES OF RANVIER
- impulses jump between
other role of MYELIN SHEATH besides increase speed
INSULATION - so can’t depolarise other axons nearby / can’t lose the depolarisation
what STAIN is good to use to see the HISTOLOGY of a NEURONE
H&E STAIN
what is GRADE 1 of NERVE INJURY
NEURAPRAXIA
- Compression (‘pins and needs’) as myelin dying (schwann cells can repair)
what is GRADE 2 of NERVE INJURY
AXONOTMESIS
- Damage to Axon (can be slowly regrown)
what is GRADE 3 of NERVE INJURY
NEUROMESIS
- LOSS of ENDONEURIAL LAYER
what is GRADE 4 of NERVE INJURY
NEUROTMESIS
- LOSS of ALL 3 LAYERS (endoneurium, perineurium, epineurium)
what is GRADE 5 of NERVE INJURY
NEUROTMESIS
- SEVERE nerve injury ie CUT with knife
PHOTORECEPTORS of the EYES:
RODS (black and white) and CONES (larger, detect colour)
react to PHOTONS coming in of different wavelengths
-> BIPOLAR CELLS -> AMACRINE CELLS -> GANGLION CELLS -> OPTIC NERVES -> BRAIN
HYPERPOLARISE when initiated (depolarising at rest)
STAIN for EYE HISTOLOGY
H&E
what is SOMATOTOPY which occurs in GREY (cell bodies) and WHITE (myelinated axons up and down) MATTER
Point-to-point MAPPING of an AREA OF THE BODY to a SPECIFIC POINT in the CNS
name of the ASCENDING NERVE PATHWAY / TRACT
SPINOTHALAMIC TRACT
- SENSORY
- to the THALAMUS
name of the DECENDING NERVE PATHWAY / TRACT
LATERAL CORTICOSPINAL TRACT
- MOTOR
what are the MACRO NON-NEURONAL GLIA CELLS of the CNS
ASTROCYTES
OLIGODENDROCYTES
EPENDYMAL
what do ASTROCYTES do
FORM BLOOD BRAIN BARRIER
SUPPORT
PHAGOCYTOSIS
what do OLIGODENDOCYTES do
MYELINATION
- PRODUCE ALL MYELIN of WHITE MATTER
to INCREASE SPEED so LESS ENERGY REQUIRED
what do EPENDYMAL cells do
SECRETE / PUSH OUT CSF through and around the brain
- CILLIATED
besides PROTECTION, SHOCK-ABSORPTION, NUTRIENTS etc role of CSF what else is it important for
LYMPHATICS OF THE BRAIN
- PROTEINS that the brain doesn’t need are pushed out and drained into the CSF
what do MICROGLIA cells do
CNS IMMUNITY
- ‘watered-down’ not as strong Immune System (prevent damage to brain)
BRAIN IMMUNE CELLS that respond to pathogens and damage
CHARACTERISTICS of the BLOOD BRAIN BARRIER that limit the passage of substances
- TIGHT JUNCTIONS in endothelial cells lining the blood vessels
- FOOT PROCESSED of ASTROCYTES further reinforces the barrier
(substances have to be actively pumped in.
only medicines allowed through are fat-based ones)
how many CELLS in CNS
100 BILLION
with 10^15 (1 quadrillion) connections - connectome
how much STORAGE in CNS
2.5 TERABYTES
ARRANGEMENT in BRAIN?
HORIZONTAL ARRANGEMENT (6)
& VERTICAL (COLUMNAR) ARRANGEMENT
what are the 6 BRAIN / CEREBRAL LAYERS
- MOLECULAR
- EXTERNAL GRANULAR
- EXTERNAL PYRAMIDAL
- INTERNAL GRANULAR
- INTERAL PYRAMIDAL
- POLYMORPHOUS
what is the MAJOR RECEIVER Horizontal Layer
When is it the largest layer?
4 - INTERNAL GRANULAR
MAJOR RECEPTIVE / SENSORY layer
SIGNALS INTO BRAIN
Largest when in PRIMARY VISUAL CORTEX
what are the MAJOR OUTPUT Horizontal Layers with SIGNALS DOWN FROM THE BRAIN
5 - INTERNAL PYRAMIDAL & 6 - POLYMORPHOUS
HORIZONTAL LAYERS 1,2,3 (Molecular, External Granular, External Pyramidal) do what
PROCESSING
how is VERTICAL ORGANISATION
CYTOARCHITECTURAL
- Neuronal size, shape, packing density, and staining intensity are all features that are used to characterize a specific cytoarchitectural area
Also Multiple CO-LOCATED COLUMNS
- if one is damaged the others can take over
ie fingertips
how is CEREBELLAR ARRANGEMENT
UNIFORM
- with 3 HORIZONTAL LAYERS
for complicated ERROR CHECKING
- smooths out signals and modifies output
which NON-NEURAL GLIAL CELL of CNS is CILLIATED
EPENDYMAL
- MACRO glial
- SECRETES CSF
which NON-NEURAL GLIAL CELL of CNS FORMS BLOOD BRAIN BARRIER
ASTROCYTES
which NON-NEURAL GLIAL CELL of CNS are the BRAINS IMMUNE CELLS
MICROGLIAL
which NON-NEURAL GLIAL CELL of CNS produces MYELINATION
OLIGODENDROCYTES
which NON-NEURAL GLIAL CELL of PNS LINES GUT BLOOD VESSELS to protect from BACTERIA
(glial meaning glue as stick nerves together)
ENTERIC GLIAL CELLS
What type of polarity is a SENSORY NEURONE
PSEUDO-UNIPOLAR
What type of polarity are MOTOR NEURONES
MULTI-POLAR
(long axon, cell bodies in spinal cord central grey)
