Lecture 7 - neuroanatomy intro Flashcards
Exam 2
Differentiate between classifications of neurons based on myelination
A - myelinated (motor functions)
B - lightly myelinated (slower, pressure, cold)
C - no myelination
Motor neurons are type ___ neurons
A
How are A-type neurons subdivided?
Size: alpha > beta > gamma > delta
Cell body
Soma (nucleus)
Dendrites
- receiving ends; project from soma
- can be excitatory or inhibitory
Dendrites are not _____
myelinated
Differentiate between EPSP and IPSP
ESPS - excitatory post-synaptic potential; more positive than average Vrm (-20mV) → depolarization
IPSP - inhibitory post-synaptic potential; more negative than average Vrm (-70mV) → hyperpolarization
**If cell Vrm is -60mV
Neurons can have _______ connections with their neighbors
10,000+ (especially decision makers) → takes a lot of info and decides if to act with AP
______ is the sending end of the neuron; send AP quickly (usually myelinated)
Axon
The end of the axon is the ______ and releases _______
presynaptic terminal; neurotransmitters
______ is the beginning part of the axon that is connected to the soma
Axon hillock
Inputs coming from the nervous system that tend to suppress activity in the neuron occur at the ______
Axon hillock - brakes for the nervous system
The neurotransmitter that typically acts at the axon hillock is _____
GABA
GABA receptors on the axon hillock increase ________ permeability
chloride
The more chloride permeability, the more _____ of cell
inhibition
_______ is GABA receptor agonist
Alcohol - the body doesn’t produce much of its own GABA with chronic alcohol use → seizures and overactivity in CNS
Natural inhibition of HR is mediated by ______, while natural inhibition of the nervous system is mediated by _____
mACh receptors linked to K+ channels
GABA at the axon hillock
Why are there no excitatory connections at the axon hillock?
it would bypass the rest of the neuron (dendrites and soma) - cell would no longer be the decision maker for all the connections from the rest of the nervous system
Glial cells are much more _______ than neurons
proliferative
A brain tumor is probably a ______ tumor instead of a neuron tumor
glial
The smallest of the glial cells are the ______
microglia
What are the 3 types of macroglia?
Astrocytes, Ependymal cells, Schwann cells/Oligodendrocytes
_______ are a big part of the BBB. How?
Astrocytes - wrap themselves around capillaries
The walls of astrocytes don’t directly constitute the BBB
The BBB is found inside the capillaries of endothelial cells (tight junctions)
Astrocytes are named because they look like a _____
star - appendages connect to the outside of the endothelial cells
What are the functions of astrocytes?
- Supporting structure in the BBB
- Regulation of metabolic environment - maintain electrolyte balance (buffer in CSF)
- Repair neurons after neuronal injury
____ are the most abundant type of glial cell
astrocytes
Our body’s regulation of pH/buffer? occurs in the _____ while in the brain, is performed by ______
kidney; astrocytes
______ are ciliated cells that produce CSF and move it around
Ependymal cells
Where are ependymal cells concentrated?
choroid plexus in each ventricle
Where is CSF produced?
Choroid plexus
Oligodendrocytes vs Schwann cells
Think COPS -
- CNS - oligodendrocytes
- PNS - Schwann cells
What is the function of microglia?
Function as the immune system for any structure that contains CSF - act as macrophages and phagocytize neuronal debris
What are the 3 neuron types?
Multipolar
Pseudounipolar
Bipolar
What do multipolar cells do?
Decision-making cells - take info and decide to fire an action potential or not
- motor neurons
What do pseudounipolar neurons do?
Sensory function - the majority of the sensory cells right outside the spinal cord
- cell body exists to make proteins and replace things, not making a decision - supportive
What do bipolar neurons do?
Special sensory - photoreceptors in retina that send messages in optic nerve
- don’t need to talk to other neurons, just pass info in form of AP to other areas
______ neurons are not found in humans, but in lower life forms
True unipolar
_____ means “sensible” or that we are consciously aware of it
Somatic
_______ are pain sensors also known as ______
Free nerve endings; nociceptors
Pressure and stretch sensors operate via
Changing sodium permeability in response to physical stretch
What are the pressure sensors?
Pacinian and Meissner’s corpuscles
Golgi tendon apparatus
Muscle spindles
______ are pressure/stretch sensors that give feedback about what skeletal muscles are doing
Golgi tendon apparatus
________ are pressure/stretch sensors that are interwoven in skeletal muscles that tell us if the muscle is contracted or not
Muscle spindles
______ take some kind of physical/environmental disturbance and turn it into an AP
Mechanoreceptors
Describe baroreceptor adaption response to high BP
- Normal MAP (100 mmHg), has normal amount of Na+ coming in
- High MAP at 150 mmHg → more Na+ coming in → more action potentials → sends info back to brainstem → pressure too high
- Desensitized after prolonged hypertension → adjust to new normal → action potential rate slows down → adaptation (takes 2 days)
- Without adaptation of baroreceptors, limited ability to respond to further changes from new normal, AP can only fire so fast → brain won’t get correct info from baroreceptors
Some sensors have ______ adaptation
Reverse - more sensitized to stimulus over time
________ is the adjustment of sensors due to prolonged stimulation
Adaptation
Slow vs fast adaptation
- Slow = 2 days, specialized sensors can adapt faster
- Fast = concerned with changes happening right now
Slow vs fast signal propagation depends on ______
priority - fast = high priority (pain), slow = low priority (tickle)
Neurons are easier to block if they are ______
Superficial
Unmyelinated
Pain receptors undergo _________ adaptation
reverse
Why is it important to stay ahead of pain?
- need to tackle pain before it gets out of control, difficult to get back in control after it starts
- can use nerve block (block where pain would be sensed in the first place)
Pain receptors have reverse adaptation
The receiving end of a synapse is called the _____
post-synaptic terminal
Superior/inferior
Higher/lower altitude
Head/feet
Dorsal/ventral
Back/front
anterior/posterior
front/back
medial/lateral
midline vs out to the side
Rostral/caudal
rostral - front and towards the top
caudal - lower and to the rear
- used for surgical procedures and neuro
distal/proximal
further/closer to system
superficial/deep
close to skin/deep in tissue
Sagittal plane
separates L/R sides
Coronal plane
Separates front and back; anterior/posterior
Horizontal plane
Think magician sawing assistant in half
Superior/inferior
Oblique plane
Odd angle
The CNS includes
brain (diencephalon and telencephalon), brain stem, and spinal cord
Telencephalon
Outer/upper/superficial portions of the brain, cerebral hemispheres
- cerebral cortex
Diencephalon
Inner/deep part of brain, connecting point between cerebral hemispheres and brain stem
- thalamus/hypothalamus
The _______ is an important relay center for the brain
thalamus
The ______ is the super important sensory area and control center of the brain
hypothalamus
The brainstem includes which 3 parts?
Midbrain (mesencephalon)
Pons
Medulla oblongata
A sulcus is a ______
groove
A really deep groove is a ______
fissure
A lump of tissue separated by grooves is a _______
Gyrus (pleural is gyri)
What are the 4 major lobes of the brain?
Frontal, parietal, occipital, temporal
What are the 3 major landmarks of the brain that divide the major lobes?
Central sulcus - frontal and parietal lobe
Temporal/temporolateral fissure - temporal and parietal/frontal lobes
Longitudinal fissure - L/R cerebral hemispheres
The _______ lobe is where we do most of our thinking
Frontal
The ______ lobe is the primary somatosensory center
Parietal
The _____ lobe is where vision is processed/ primary visual cortex
occipital
The _____ lobe is where the auditory processing center is
Temporal
What is the anatomical marker for dissecting a human brain?
The central sulcus
__________ is the bridge in the brain that allows cross-talk from L → R and back. Where is it located?
corpus callosum
occurs at the white space (myelinated neurons) right below the longitudinal fissure
The area of the brain responsible for Word Formation is ______. Where is it located?
Broca’s Area - located in frontal lobe - speaking is more motor than sensory; requires more thinking
The area of the brain responsible for Language Comprehension is ______. Where is it located?
Wernicke’s Area - specific part of temporal lobe - understand and comprehend language
The motor cortex is located in the ______ lobe
Frontal - sits anterior to central sulcus, most posterior/rear part of frontal lobe
The premotor cortex is located in the ______ lobe
The front of the frontal lobe
pre-central gyrus = primary _______
motor cortex
post-central gyrus = primary _______
Somatosensory Cortex
The somatosensory cortex is located in the ______ lobe
parietal lobe - anterior
The ______ is the area of the brain responsible for emotional responses. Where is it located?
Limbic system
Temporal lobe
Pain is worse if the _______ gets involved
limbic system
The spinal cord is fairly narrow, about the size of a _______
quarter
White matter vs grey matter in the spinal cord
White matter
- Generally axons
- White = Myelin
- Not many cell bodies
- Sending/receiving
Grey matter - non-myelinated neurons
- CELL BODIES
- Dendrites
- Decision-making center
Grey matter is ______ to white matter in the brain because it needs more _______
Superficial, blood flow
A concussion or head injury can damage ______
Grey matter → less processing ability; suspending brain in CSF gives buffer to prevent this
In the spinal cord, white matter is _____ to grey matter
superficial
_______ is the space in the grey matter that connects the L/R sides of the cord to allow x-over
Lamina X
_______ is the space in the white matter that connects the L/R sides of the cord to allow x-over
Anterior white commissure (AWC)
_______ is when information moves from one side of the brain or spinal cord to the other
x-over
What are the 3 spinal landmarks in the white matter?
Posterior median fissure
Anterior median fissure
Central canal (hole in the middle)
Which fissure in the spinal cord is wider? Why?
Anterior median fissure - has larger arterial blood vessel parked in it
What is the function of the central canal?
Lined with ciliated cells that move CSF down the cord
- opening within lamina X
The grey matter projections in the spinal cord are known as the _____
Horns - dorsal and ventral
- larger anterior horns
Sensory information is fed into the _____ horns
Dorsal
Motor function comes out of the _____ horns
Ventral
Where do we aim for spinal blocks/epidurals?
Back of the spinal cord where sensory information is
Lumbar spine
Thoracic approach difficult because of downward angle of spinous process.
Spinal cord perfusion comes from the _______
Intercostal arteries
The anterior spinal artery sits in the _________
anterior medial fissure
_______ communicate information horizontally from the spinal nerve and roots to the spinal cord
Rootlets
More ascending columns are located in the _____ of the cord
Rear/posterior, also some laterally and in front
Ascending columns primarily communicate _____ information
Sensory
Descending columns primarily communicate _____ information
Motor
Descending columns are located in the _____ of the cord
Front and sides
The anterior and posterior roots come together to form the ______
Spinal nerve
What is unique about the structure of the posterior root?
Has spinal ganglion bulge - a collection of cell bodies from psuedo-uniploar sensory neurons (most of sensory cells)
Why does the anterior root not have a spinal ganglion?
The cell bodies are located in the anterior horn
How many vertebrae are in the cervical (C) spine? How many pairs of spinal nerves?
7 vertebrae
8 pairs of spinal nerves
Spinal nerves are located on top of respective vertebra - C1 spinal nerve comes out above the C1 vertebra
How many vertebrae are in the thoracic (T) spine? How many pairs of spinal nerves?
12 and 12
How many vertebrae are in the lumbar (L) spine? How many pairs of spinal nerves?
5 and 5
How many vertebrae are in the sacral (S) spine? How many pairs of spinal nerves?
1 vertebra and 5 pairs of spinal nerves
- start with 5 vertebrae at birth then they fuse together
How many vertebrae are in the coccygeal (Co) spine? How many pairs of spinal nerves?
1 pair of spinal nerves
2 vertebrae
- Start with 4 as babies, fuse into 2 as adults
What are the 5 sections of the spine?
Cervical, thoracic, lumbar, sacral, coccygeal
What is the name for the diagram that shows which spinal nerves control specific areas of the body?
“Dermatome Man”
_______ are cushioning between vertebrae to brace impact, get worn down as you get older
Discs
What is the normal curvature in the spine?
Lordosis (anterior/convex) - cervical and lumbar
Kyphosis (posterior/concave) T-spine, sacrum, and coccygeal sections
Pathologic curvature is also known as
Thoracic kyphosis - hunchback
Scoliosis - abnormal lateral curvature
Kyphoscoliosis - kyphosis and scoliosis together
Babies only have ______ curvature
Kyphotic - can’t hold up head or walk
__________ is the weight-supporting structure of the spine, what the discs sit on
Vertebral Body
- as you go higher up the spine, vertebral bodies get smaller because they support less weight
_______ is the U-shaped structure that comes off the vertebral body, opening where the cord and spinal roots are housed
Vertebral arch
The vertebral arch contains the ____ and the _____
Pedicle (attached to vertebral body) and lamina (curve)
The ______ is the palpable bony projection that comes out the back of the spine
Spinous process (1)
_______ are the bony projections that come out the sides (lateral) of the arch
Transverse Process (2)
_______ are the bony projections that come up from the top of the arch
Superior Articular Process
Articular means
Connecting things together
The Superior Articular Process articulates with the _______
Inferior Articular Process
________ are the bony projections that come down from the bottom of the arc
Inferior Articular Process
The _______ is the opening where the spinal cord is located
Vertebral foramen
The _______ is where the spinal nerves can exit on each side of spine
inferior vertebral notch
The lamina is ________ to the pedicle
posterior
The ________ joint is where the superior and inferior articular processes connect
Facet - a sliver of cartilage between bones
