BRAIN EMBRYOGENESIS:
Major regions:
1. Prosencephalon (forebrain)
a. Telencephalon: cerebrum
b. Diencephalon: epithalamus, thalamus,hypothalamus
2. Mesencephalon (midbrain)
a. Mesencephalon: cerebral peduncles, colliculi
3. Rhombencephalon (hindbrain)
a. Metencephalon: pons, cerebellum
b. Myelencephalon: medulla oblongata
ORGANIZATION OF BRAIN:
ü White matter lies deep to the gray matter of the cortex.
ü Within the masses of white matter:
o discrete innermost clusters of gray matter called cerebral nuclei (or basal nuclei).
o oval, spherical, or sometimes irregularly shaped clusters of neuron cell bodies.Q & A on brain meninges: Dura matter:Tough membrane composed of two fibrous layers.
Strongest of the meninges.
Dura mater is composed of two layers.
periosteal layer, the more superficial layer, attaches to the periosteum of the cranial bones
meningeal layer lies deep to the periosteal layer
The meningeal layer is usually fused to the periosteal layer
Exception: in specific areas where the two layers separate to form large, blood-filled spaces called dural venous sinuses.
Arachnoid:
Also called the arachnoid mater or the arachnoid membrane.
Lies immediately internal to the dura mater.
Partially composed of a delicate web of collagen and elastic fibers, termed the arachnoid trabeculae.
Between the arachnoid and the overlying dura mater is the subdural space.
Immediately deep to the arachnoid is the subarachnoid space.
Pia matter:
The innermost of the cranial meninges.
Thin layer of delicate connective tissue that tightly adheres to the brain and follows every contour of the brain surface.
Major regions:
1. Prosencephalon (forebrain)
a. Telencephalon: cerebrum
b. Diencephalon: epithalamus, thalamus,hypothalamus
2. Mesencephalon (midbrain)
a. Mesencephalon: cerebral peduncles, colliculi
3. Rhombencephalon (hindbrain)
a. Metencephalon: pons, cerebellum
b. Myelencephalon: medulla oblongata
ORGANIZATION OF BRAIN:
ü White matter lies deep to the gray matter of the cortex.
ü Within the masses of white matter:
o discrete innermost clusters of gray matter called cerebral nuclei (or basal nuclei).
o oval, spherical, or sometimes irregularly shaped clusters of neuron cell bodies.Q & A on brain meninges: Dura matter:Tough membrane composed of two fibrous layers.
Strongest of the meninges.
Dura mater is composed of two layers.
periosteal layer, the more superficial layer, attaches to the periosteum of the cranial bones
meningeal layer lies deep to the periosteal layer
The meningeal layer is usually fused to the periosteal layer
Exception: in specific areas where the two layers separate to form large, blood-filled spaces called dural venous sinuses.
Arachnoid:
Also called the arachnoid mater or the arachnoid membrane.
Lies immediately internal to the dura mater.
Partially composed of a delicate web of collagen and elastic fibers, termed the arachnoid trabeculae.
Between the arachnoid and the overlying dura mater is the subdural space.
Immediately deep to the arachnoid is the subarachnoid space.
Pia matter:
The innermost of the cranial meninges.
Thin layer of delicate connective tissue that tightly adheres to the brain and follows every contour of the brain surface.
