Exam 3, Day 3 Lecture Flashcards
Two types of Blood Brain Barrier
- Blood - CSF Barrier 2. Blood - ECF Barrier (BBB)
Ventricles of the brain
Right Lateral Ventricle Left lateral Ventricle 3rd ventricle 4th ventricle
The connection between the lateral ventricles and 3rd ventricle
Interventricular foramen
From the 3rd ventricle, CSF is conveyed to the 4th ventricle via ____.
Cerebral aqueduct or Aqueduct of Sylvius
How apertures are there in the 4th ventricle
Total of 3 (2 lateral aperture and 1 median aperture)
This is the passageway of CSF from the 4th ventricle to the spinal cord.
Central canal
2 contacts of the CSF in the body
- Outside of the brain and Spinal cord 2. In the central canal and ventricles of the brain
It covers the cranium, a broad flat tendon and is associated with muscle fibers in the frontal and occipital region.
Galea Aponeurotic
Membrane that covers a bone.
Pericranium or periosteum
Layer below the skull
Periosteal layer of the Dura matter.
Layers of the brain aka meninges. (from outside to inside)
- Dura mater 2. Arachnoid mater 3. Pia mater
2 layers of Dura Matter
- Periosteal layer 2. Meningeal layer
The space created due to deviation between the periostal layer and the meningeal layer. This is a channel for venous blood.
Superior sagittal sinus
Layer with whisp material. It has a spidery-web appearance.
Arachnoid mater
Protrusion of arachnoid mater through the meningeal layer of the dura, into the superior sagittal sinus.
Arachnoid granulations or villi
This is the site where CSF returns to the venous blood (site reabsorption of CSF)
Arachnoid granulations or villi
This is the inner most layer of the meninges, located on the surface of the brain parenchyma.
Pia mater
Depression on the surface of the brain
Sulcus
Deeper depression on the surface of the brain
fissure
Two layers of meningeal dura forms a partition called ___. It helps keep the brain in place within the cranial vault.
Falx cerebri (Dura)
The major blood vessels of the brain run in the _____.
subarachnoid space.
Rupture of major blood vessel in the brain will lead to ___.
subarachnoid hematoma
Potential space between the outer layer (periosteal layer) of the dura and the skull
epidural space.
Rupture of this vessel can cause epidural hematoma is the ____.
Middle meningeal artery (supplies the dura and skull)
This is the space between the meningeal layer of the dura and the arachnoid mater.
Subdural space
Total CSF fluid
150 ml (in any given time)
Specific gravity of brain
1.04
Specific gravity of CSF
1.007
Dry weight of brain
1400 grams
Weight of brain with CSF
25 grams
How many ml of CSF are produced each day?
500-600 ml
CSF is produced by (2)
choroid plexus and ependymal cells in the 4 ventricles
Normal CSF pressure.
10 mmHg or 13.6 cm H20 (in supine)
Reabsorption of CSF occurs through the arachnoid villi which are mostly along the _____.
superior sagittal sinus.
How many turnovers of CSF production - reabsorption in a day?
4
What drives the movement of CSF from the subarachnoid space back into the venous blood?
pressure (increased pressure in the subarachnoid space)
Additional circulation created by cilia that are on the cells that line on the ventricles. They help move the CSF.
ependymal cilia
This is a protein-poor serous plasma which is secreted by choroid plexus cells and ependymal cells.
CSF (resembles like serum)
2 Main functions of the CSF
- Shock absorber for brains and Spinal cord 2. Second circulatory fluid delivering oxygen and nutrients and removing metabolites.
Ventricles are the series of four interconnecting cavities of the brain, lined by _____ and with a specialized choroid plexus (capillary network) which produce the CSF.
ependymal cells
Capillary network within the brain.
choroid plexus.
What type of cell is ependymal cell?
motile, simple cuboidal epithelium-like cells with microvilli.
Type of Blood-brain barrier: Located at the choroid plexus of the 2 lateral, 3rd, and 4th ventricles.
Blood - CSF barrier (BCSFB)
Type of blood-brain barrier: Located in the CNS capillary bed of brain tissue
Blood - ECF (brain tissue) barrier. aka BBB
It is a tuft of capillaries covered by ependymal cells in each ventricle.
Choroid plexus
True of False: Ependymal cells line the entire ventricle not just where the capillaries project from the surface.
True
Layers of the choroid plexus
- Microvilli 2. Tight junctions 3. Ependymal cells 4. Connective Tissue 5. Basement membrane
Total protein in CSF
30 mg/ 150 ml or 20 mg/dL
Osmolality of Plasma and CSF
289 mosm/kg
This is the barrier between the blood and the ECF or nervous tissue.
Blood - ECF barrier or BBB
These glial cells are interposed between the capillary and the neuron. They have foot processes that surround the capillary.
Astrocytes
Another name for neuron
Neurones
The foot processes of astrocyte cover ____% of capillary surface.
97-99%
The brain capillary endothelial cells are joined by tight junctions of _____ providing an effective barrier to many molecules.
high electrical resistance.
True or False: Astrocytes also play a role in nutritional supply of oxygen and glucose to the neurons.
True.
Pathways across the BBB
- Paracellular aqueous 2. Transcellular lipophilic 3. Transport Proteins 4. Receptor-mediated transcytosis 5. Adsorptive Transcytosis
A type of glial cells that is part of the myelinated axon, forms part of the myelin sheath.
Oligodendrocytes
The delivery of ____ and ___ from the blood to neurons is regulated by astrocytes.
oxygen and glucose.
The Cerebral cortex is the outer ____ mm part of the brain, bathed with CSF.
3 - 4 mm.
Areas of the brain exposed to blood (outside the BBB)
- Subcommissural organ 2. Subformical organ (SFO) 3. Organum Vasculosum of the lateral Terminalis (OVLT) 4. Area Postrema 5. Pineal Body 6. Posterior Pituitary
This gland secretes melatonin.
Pineal Body
What is secreted from the subcommissural organ? (2)
Somatostatin, SCO-spondin
The areas outside the BBB are involved in ____ (2)
osmoregulation and blood chemistry
This type of organs can store secretions until signal is received.
Neurohemal organs
What is composed of the circumventricular areas? (2)
3rd and 4th ventricles
Hypothalamus, the thirst center, responds to what type of feedback mechanisms?
positive feedback
This is the vomiting center. It also detects toxins in the blood, and increases BP (ANS)
Area Postrema
Where is Area Postrema located?
Dorsal medulla
This receptor causes salt appetite
ANG II receptor
During infection, ____ acts on OVLT to produce fever.
IL-1
An acquired cause of hydrocephalus
tuberculous meningitis
A progressive condition in which an abnormal accumulation of CSF in the cerebral ventricles causes enlargement of the skull and compression of the brain.
Hydrocephalus
Management of patients with hydrocephalus
- Compensation by decreased cerebral blood volume 2. ventriculoperitoneal shunt
One of the most common causes of hydrocephalus
Aqueductal stenosis
This can also cause hydrocephalus.
Primary ciliary dyskinesia
A protein secreted by Subcommissural organ which forms tubules that keep the aqueduct open.
SCO-spondin
Incidence of hydrocephalus (age group)
infants and >60yo
Normal pressure hydrocephalus accounts for ____% of all dementia cases.
5-6%
Type of hydrocephalus where elevated CSF pressure causes enlargement of ventricles followed by return to normal CSF pressure.
Normal pressure hydrocephalus (NPH)
10 symptoms associated with Adult-onset Hydrocephalus
- Seizures 2. Sudden Falls 3. Change in personality or behavior 4. Headaches 5. Leg weakness 6. Irritability 7. Nausea 8. Difficulty focusing the eyes 9. Drowsiness 10. Unsteady walk or gait
Primary symptoms of NPH
- gait disturbance 2. Dementia/ forgetfulness 3. Bladder control problems
Two groups of cells in the CNS
Neurons, Neuroglia
Types of Neuroglia (4)
Astrocytes Microglia Ependymal cells Oligodendrocytes
Basic Neuron types
Bipolar Unipolar Multipolar Pyrimidal cells
This is considered as the resident “macrophage” of the CNS
Microglial cells
Sensory pathway starts in a peripheral structure. (e.g. pain impulse goes up to the spinal cord.) What neuron receives this impulse and carries it to the spinal cord?
Axons of the first-order neurons
Where does the first-order neuron synapse with second-order neuron? (This is where you find the cell body of the 2nd order neuron)
grey matter (any part of the spinal cord)
Where can you find cell bodies?
grey matter
Where can you find the processes (or tracts) of the cell bodies?
white matter/ fiber tracts
Where does 2nd order neuron synapse with 3rd order neuron?
grey matter of the thalamus
From the thalamus, where does the 3rd order neuron run to? This is the primary sensory cortex.
Postcentral gyrus
This is the relay station to the primary sensory cortex. This is where you find the cell body of the third order neuron
Thalamus
Other name for axons of the second-order neurons
Lateral spinothalamic tract
The sensory tract relays all sensation to the post central gyrus except for the sense of ___.
smell (olfactory)
Where does the corticospinal tract (motor pathway) start?
Precentral gyrus (primary motor cortex)
Where does the upper motor neuron synapse with the lower motor neuron?
grey matter of the ventral root.
The lower motor neuron leaves from the ____ going to the target skeletal muscle.
ventral root
This is the largest part of the coticospinal tract.
Lateral corticospinal tract (in white matter)
Where can you find the cell body of the first order neuron?
Dorsal root ganglia
Where can you find the cell body of the upper motor neuron?
precentral gyrus
Where can you find the cell body of the lower motor neuron?
Ventral root
This separates the frontal lobe from the parietal lobe of the brain
Central sulcus
Other name for Primary sensory cortex
Primary somesthetic cortex
This is the sensory speech area (understanding the meaning of WRITTEN words).
Wernicke’s area
This is the motor speech area (movement of skeletal muscles for vocalization)
Broca’s Area
Auditory area in the temporal lobe. (understanding of spoken words)
Primary auditory cortex
This is an elevation between sulci
gyrus
Depression in the brain
Sulcus
Outer layer of the brain, contains neuron cell bodies.
Cerebral cortex
Inner layer of the brain. It has myelinated axons
Cerebral white matter.
