Lecture 19 Flashcards
What division of the skeleton supports the central nervous system? which two parts of this division are most important for this?
The axial skeleton, the two most important parts are the skull and the vertebral column.
How many bones does the skull contain? how are they distributed? What about the vertebral column?
28 bones, 8 of which are in the cranium, 14 are facial bones, 6 are ear bones.
The vertebral column has 26 bones, 7 cervical vertebrae, 12 thoracic, 5 lumbar, 5 fused vertebrae in sacrum and 4/5 fused vertebrae in coccygeal.
What are the names of the bones of the cranium? What sutures join these bones
The cranium bones are the frontal bone (most anterior), the sphenoid which spans through the cranium just inferior to the frontal bone, two parietal bones immediately posterior to the frontal(joined to frontal by the coronal suture, and themselves by the saggital suture), two temporal bones immediately inferior to the parietal bones (joined by squamous suture) and one occipital bone at the most posterior point of the cranium, (joined by lambdoidal suture to parietal bones).
What are the gaps between sutures known as prior to the sutures joining? What can premature closure cause?
The gaps are known as fontanelles and premature closure can block brain growth, causing cognitive impairment.
What are the seven external facial bones?
The two zygomatic bones are found on either lateral end of the face (cheek bones), The maxillary bones are immediately medial to the zygomatic bones and stretch from the upper jaw to the more medial two nasal bones. The mandible is the most inferior bone of the facial skeleton and is your lower jaw.
What are the meninges? and what are the three major layers?
The meninges are layers of protective tissue which are formed between the skull and the brain, The three layers from outermost to innermost are the Dura mater, arachnoid and pia mater.
What is the function of the dura mater?
A dense and fibrous (tough) layer, consists of two sub layers, the inner of which forms the three dural reflections which separate the major brain divisions via the brain fissures. Also forms venous sinuses between the two sub layers, these function to drain venous fluid from the brain.
What are the three dural reflections?
Falx cerebri: separates the cerebral hemispheres along the median plane.
Falx cerebelli: separates the cerebellar hemispheres along the median plane.
Tentorium cerebelli: Separates the cerebrum from the cerebellum along the horizontal plane.
What is the function of the arachnoid layer?
Contains blood vessels and cerebrospinal fluid in the subarachnoid space between itself and the pia mater, this space is made through the use of a pier like foundation which holds the arachnoid layer well above the Pia mater. Also forms arachnoid granulations (villi), which perforate the dura mater and transport old cerebrospinal fluid into the venous sinus.
What is the function of the Pia mater?
A transparent and delicate layer which blood vessels sit on top of and which sticks to the brain, including its gyri and sulci.
What is the layering of spinal cord meninges?
Same as in the brain, pia mater
Where is cerebrospinal fluid produced?
In the choroid plexus, which lines the ventricles of the brain.
What are the major parts of the ventricular system?
The lateral ventricles on either side of the brain, the third ventricle connected medially and inferiorly by the interventricular foramen, the fourth ventricle which is connected by the cerebral aqueduct. These outflow into the central canal of the spinal cord or the subarachnoid layer.
What is the cerebral spinal fluid circulation path?
lateral ventricle > 3rd ventricle > cerebral aqueduct > 4th ventricle > subarachnoid layer.
What is Hydrocephalus?
A disease caused by abnormal accumulation of CSF in brain, leading to increased intracranial pressure and hence enlargement in the heads children with the disease (as the sutures have not yet formed), also causes convulsions, tunnel vision and mental disability.
