The CNS is crucial to the operation of the body, and any compromise in the brain and spinal cord can lead to severe difficulties. The CNS has a privileged blood supply, as suggested by the blood-brain barrier. The function of the tissue in the CNS is crucial to the survival of the organism, so the contents of the blood anatomy of brain and spinal cord pdf simply pass into the central nervous tissue.
Blood Supply to the Brain A lack of oxygen to the CNS can be devastating, and the cardiovascular system has specific regulatory reflexes to ensure that the blood supply is not interrupted. There are multiple routes for blood to get into the CNS, with specializations to protect that blood supply and to maximize the ability of the brain to get an uninterrupted perfusion. Arterial Supply The major artery carrying recently oxygenated blood away from the heart is the aorta. The very first branches off the aorta supply the heart with nutrients and oxygen. The next branches give rise to the common carotid arteries, which further branch into the internal carotid arteries. The external carotid arteries supply blood to the tissues on the surface of the cranium. The internal carotid artery enters the cranium through the carotid canal in the temporal bone.
A second set of vessels that supply the CNS are the vertebral arteries, which are protected as they pass through the neck region by the transverse foramina of the cervical vertebrae. The vertebral arteries enter the cranium through the foramen magnum of the occipital bone. Watch this animation to see how blood flows to the brain and passes through the circle of Willis before being distributed through the cerebrum. The circle of Willis is a specialized arrangement of arteries that ensure constant perfusion of the cerebrum even in the event of a blockage of one of the arteries in the circle. The animation shows the normal direction of flow through the circle of Willis to the middle cerebral artery. The superior sagittal sinus runs in the groove of the longitudinal fissure, where it absorbs CSF from the meninges. Protective Coverings of the Brain and Spinal Cord The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which protect the brain.
Spinal shock and neurogenic shock can occur from a spinal injury. Explains the individual systems of the body – but not to the extent that it causes cell death in that region. Protective Coverings of the Brain and Spinal Cord The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which is surrounded by the third ventricle. And the spinal cord. Flap design and dimensions, the midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons.
The dura mater is a thick fibrous layer and a strong protective sheath over the entire brain and spinal cord. This image shows a cross-section through the brain. The different meningeal layers are labeled. The layers of the meninges in the longitudinal fissure of the superior sagittal sinus are shown, with the dura mater adjacent to the inner surface of the cranium, the pia mater adjacent to the surface of the brain, and the arachnoid and subarachnoid space between them. Dura Mater Like a thick cap covering the brain, the dura mater is a tough outer covering. It encloses the entire CNS and the major blood vessels that enter the cranium and vertebral cavity. It is directly attached to the inner surface of the bones of the cranium and to the very end of the vertebral cavity.