Intro to Neuro Flashcards
1
Q
CNS gray matter
A
Cell bodies
- found in columns
- “nuclei”
- “cortex”
2
Q
CNS white matter
A
cell processes (myelin sheath) - found in tracts (fasciculi, funiculi)
3
Q
Schwann cells
A
cover nearly all PNS neurons
- provide metabolic support and electrical insulation
4
Q
Oligodendrocytes
A
myelinate several axons in the CNS
5
Q
Astrocytes
A
CNS glia that form end feet, help regulate ions and form scar tissue
- surround blood vessels
6
Q
Ependymal cells
A
CNS glia that line ventricles
7
Q
Microglia
A
CNS glia that act as cleaners
8
Q
Medulla
A
lowest portion of brain stem
- important in vital reflexes (CV and respiratory)
9
Q
Pons
A
“gatekeeper of the brain”
- has cerebellar peduncles (flowery process: a nerve tract that permits communication between the cerebellum and the other parts of the central nervous system.)
- tegmentum: forms the floor of the midbrain
10
Q
Midbrain
A
- imp. for vital reflexes
- Has cerebral peduncles
- Tectum: forms the roof
- superior colliculi: visual relay
- inferior colliculi: auditory relay
11
Q
thalamus
A
part of diencephalon
- two sides: left and right side
- forms lateral borders of third ventricle
- primary fn: relay of ALL sensory info to cerebral cortex “ post office “
12
Q
hypothalamic sulcus
A
a groove in lateral wall of third ventricle, marking the boundary between the thalamus and hypothalamus.
13
Q
hypothalamus
A
Components:
- forms floor of 3rd ventricle
- infundibulum
- two mammilary bodies
- master regulator of ANS
14
Q
frontal lobe of cerebrum
A
- MOTOR: primary motor cortex located here
Components
- premotor and supplementary motor cx’s
- Broca’s area: area in left frontal lobe that works in motor speech
- precentral, superior, middle, inferior gyri
- gyrus rectus
15
Q
Pareital lobe
A
- primary somatosensory cortex (postecentral gyrus): initial processing of tactile and proprioceptive information
components:
- postcentral gyrus
- superior parietal lobe
- inferior parietal lobe: supramarginal gyrus and angular gyrus, Wernickes area (made of supramarginal gyrus and angular gyrus - language comprehension)
16
Q
temporal lobe
A
located laterally
- Primary auditory cortex
- Wernicke’s area
- higher order visual processing
- learning and memory (hippocampus)
components: superior/middle/inferior gyri
17
Q
Occipital lobe
A
primary visual cortex (initial spot where all visual sensory will go)
Components:
- Cuneus (superior portion)
- lingual gyrus (inferior portion)
18
Q
Limbic lobe
A
deeper lobe, located beneath the outer cortex
- emotional responses, drive related behavior, memory
Components: cingulate gyrus, parahippocampal gyrus
19
Q
cerebellum
A
“little brain” - flowerly mass located caudal to brainstem
Primary fn: coordination
Components:
- vermin: midline worm
- 2 lateral hemispheres
20
Q
two separate routes to get blood into cranial vault?
A
internal carotid aa. and vertebral aa.
- internal carotid a. enters skull at carotid canal to join cerebral arterial circle
- 3 cortical branches, deep perforating branches.
21
Q
basilar aa.
A
single a. where the two vertebral aa. joint and enter through foramen magnum
- sits on ventral aspect of pons
22
Q
The blood brain barrier
A
- set up by tight junctions between endothelial cells: endothelial cells are without pores or fenestrations
- space between intravascular space and CNS ECF
- astrocytic end feet INDUCE the formation of tight junctions (they do not form it)
23
Q
What can pass through the Blood-brain barrier?
A
- small molecues (s)
24
Q
Where is CSF produced?
A
choroid plexus: ventricles are site of CSF production
25
ventricular system?
- 4 ventricles in brain that are continuous with the central canal
- continuous with SAS (subarachnoid space- anatomic space between the arachnoid membrane and pia mater.)
- ventricles are site of CSF production via choroid plexus
- lined with ependymal cells (ciliated epithelial cells that can move fluid)
26
boundaries of lateral ventricle?
```
Roof: corpus collosum
Floor: thalamus
lateral wall: caudate nucleus
Roof of inferior horn: tail of caudate
floor of inferior horn: hippocampus
```
27
boundaries of third ventricle?
lateral walls: diencephalon
| Floor: optic chiasm and infundibulum
28
Mesencephalic aqueduct
connection of 3rd-->4th ventricle
| - no choroid plexus
29
boundaries of 4th ventricle?
roof: cerebellum
floor: pons/medulla
3 openings to SAS: median (x1), lateral (x2)
30
important facts of CSF:
produced from blood via choroid plexus
- protects CNS, gives buoyancy, decreases weight
- extracellular fluid
- pH influcences respiratory centers
- active and selective production
- passive reabsorption back into venus-sinus system (dependent on pressure gradient- if perturbed, will have hydrocephalus)
31
choroid plexus
located at roof of every ventricle
- choroid epithelium is continuous with ependymal cells lining ventricles
- they are modified epindymal cells: tight junctions, forming blood CSF barrier
- ependymal cells of choroid epithelium surround fenestrated capillaries
- free exchange occurs between capillary and choroid eptiehlium
32
CSF circulation?
from lateral ventricle --> interventricular foramen --> third ventricle --> aqueduct of midbrain --> 4th ventricle --> subarachnoid space (which suspends the brain), and all the way around spinal cord
32
CSF circulation?
from lateral ventricle --> interventricular foramen --> third ventricle --> aqueduct of midbrain --> 4th ventricle --> subarachnoid space (which suspends the brain), and all the way around spinal cord
33
how does CSF return to venous blood?
arachnoid villa (arachnoid granulation) is the site of CSF reabsorption.
- CSF in SAS will travel through arachnoid granulations which poke into venous sinus system of brain: they have one way valves that are pressure dependent. If pressure is high in SAS, the CSF will flow into the venus-sinus system and will be reabsorbed.
- if there is increased jugular venous pressure, there will be less shunting of CSF, and thus increased CSF pressure
33
how does CSF return to venous blood?
arachnoid villa (arachnoid granulation) is the site of CSF reabsorption.
- CSF in SAS will travel through arachnoid granulations which poke into venous sinus system of brain: they have one way valves that are pressure dependent. If pressure is high in SAS, the CSF will flow into the venus-sinus system and will be reabsorbed.
- if there is increased jugular venous pressure, there will be less shunting of CSF, and thus increased CSF pressure
34
primary affarents
primary affarents convey info TO CNS from periphery
- Cell body is outside CNS in peripheral ganglion
- NEVER decussate, always stay ipsilateral
(in body, cell body usually located in dorsal root ganglia)
35
contralateral awareness
information from right side of body is sent to the left Cx
| - at some point somatosensory info will have to decussate on its path up to cortex.
36
Somatosensory inputs
(sensation from skin and proprioceptive information)
- primary affarents are divergent (will give off hundreds of branches)
- i.e. info sent in reflex arcs, sent to Cx via thalamus for conscious feeling, info to cerebellum to coordinate mvmt.
37
Decussation
somatosensory pathways decussate contralaterally, somewhere between origin and destination.
38
LMNs
- axons of Lower motor neurons convey info from CNS to mm.
- this is the FINAL COMMON PATHWAY
- Cell bodies are located in CNS (for spinal cord will be in ventral horn, for cranial nn. it will be in named nuclei in brainstem.)
- never decussate
39
contralateral control
the left cortex (cerebral hemisphere) controls the right side of the body
40
UMNs
upper motor neurons are any neuron whose activity affects a LMN
- located in cerebral cx or brainstem
- major pathways decussate (corticospinal tract travels from cortex to spinal cord) - main voluntary pathway that will decussate between origin and destination
41
shortest path
2 neurons
UMN will decussate
LMN will remain ipsilateral
42
Homunculus
primary motor cortex is somatotopically arranged
43
wiring principles of cerebellum
"little brain"
- info. comes in from ipsilateral side
- coordinates ipsilateral side
- coordinates rate, range, force (not conscious control)
- acts as a "comparator"
- alcohol has effect on cerebellum
44
sensory wiring principles?
audition: bilateral
olfaction: ipsilateral
gustation: ipsilateral
visceral: ipsilateral
45
Motor wiring principles?
vestibulospinal: ipsi and bi
tectospinal: bilateral ("visual reflexes": midbrain to spinal cord)
Reticulospinal: ipsi and bi (loose aggregate of cell bodies located throughout the brainstem)
