What are the three primary brain vesicles that develop from the neural tube? When do these emerg?
Forebrain (prosencephalon), Midbrain (mesencephalon), Hindbrain (rhombencephalon)
These divisions emerge during the development of the central nervous system.
What is the neurocoel?
Fluid filled internal cavity of the neural tube. Begins as a hollow tube (neural tube)
The neurocoel is a crucial structure during the development of the CNS.
What are the 8 cranial bones?
- Occipital
- 2 Parietal
- Frontal
- 2 Temporal
- Sphenoid
- Ethmoid
These bones protect the brain and are separate at birth but fuse along sutures.
What are the four types of sutures in the cranial bones and how are they in relation to one another at birth?
- Lambdoidal
- Coronal
- Sagittal
- Squamous
These sutures are immovable and develop as the cranial bones fuse.
What is the role of the dura mater?
- Tough, thick collagenous tissue that protects the brain
- inner and outer fibrous layer
- no epidural space
- gap in between (sagital sinus) that contains tissue fluid and blood vessels
The outer layer is fused to the bones of the cranium, eliminating the epidural space.
What is the function of cerebrospinal fluid (CSF)?
- Cushioning
- Supporting the brain
- Transport of solutes (constant chemical communication with CNS)
CSF is essential for maintaining a stable environment for the brain.
What structures are involved in the formation of the ventricular system?
- Lateral ventricles
- 3rd ventricle
- Mesencephalic aqueduct
- 4th ventricle
These structures develop from the neurocoel and are crucial for CSF circulation.
How is cerebrospinal fluid (CSF) produced?
Secretion by specialized ependymal cells in the choroid plexus through hyperfiltration process. Similar to plasma, except little to no protein and cholesterol.
CSF is similar to blood plasma but contains little or no protein and cholesterol.
What is the blood-brain barrier? What solutes can pass through the membrane? Why is meningitis difficult to treat?
- A barrier that isolates the CNS from general circulation
- small lipid soluble compounds can diffuse across
- Antibiotics must be able to pass through the BBB to treat meningitis
It allows only small, lipid-soluble compounds to diffuse across endothelial cell membranes.
What are the main functions of the hypothalamus?
- Controls autonomic nervous system
- Regulates endocrine system
- Organizes behaviors related to survival
These behaviors include fighting, fleeing, feeding, and mating.
What is the primary visual cortex also known as? Where is it located?
Area V1, (Brodman’s) Area 17, Striate Cortex. Located at the back of the Occipital lobe.
It receives inputs from the lateral geniculate nucleus (LGN) of the thalamus.
What is the role of the amygdala? What system is it part of?
Reward/punishment center with profound effects on behavior. Part of the Limbic system
It is part of the limbic system and plays a crucial role in emotional responses.
Fill in the blank: The primary motor cortex is organized in a _______ manner.
Somatotopically
This organization creates a motor homunculus representing different body parts.
True or False: The lateral ventricles are directly connected to each other.
False
Each lateral ventricle communicates with the 3rd ventricle through the intraventricular foramen.
What is the role of the thalamus?
Relay station for most sensory neural inputs to the cerebral cortex
It is crucial for sensory processing and perception.
What is the function of the hippocampus? What system is it part of?
Necessary for the creation of memories. Part of the limbic system.
It is a site of many synapses capable of long-term changes.
What are commissure fibers?
Fibers that connect corresponding regions of the two hemispheres (corpus callosum, ant+post commissure and fornix)
Major examples include the corpus callosum and anterior commissure.
Anatomical Structures of the Forebrain (Prosencephalon):
Lateral ventricles, third ventricle, telencephalon, diencephalon, cerebral cortex (major structure, variety of functions), basal ganglia (control of movement), limbic system (reward/punishment), thalamus (“relay station of the brain”, sensory neural inputs), hypothalamus (flight/flight behaviours)
Anatomical Structures of the Midbrain (Mesencephalon):
Cerebral Aqueduct, mesencephalon, Tectum tegmentum
Anatomical Structures Hindbrain (Rhombencephalon):
Fourth Ventricle, Metencephalon, Myelencephalon, Cerebellum, Pons, Medulla oblongata
What is the Circle of Willis, what are its functions and how is it created?
The Circle of Willis is an anastomosis between the Basilar artery and the bilateral internal carotid arteries. Its the brains blood supply and prevents from blockage of blood to the brain.
What are the three mechanical forces that protect the brain?
- The bones of the cranium
- The cranial meninges
- CSF
What is the Pia Mater?
It is the innermost membrane of the meninges, adheres most closely to the surface of the cortex. It extends into the folds and along the blood vessels.
Name the three dural Folds.
- Falx cerebri
- Tentorium Cerebelli
- Falx Cerebelli
