Organs Meninges Cross Section
Skin of Scalp
The skin on the head from which head hair grows. It contains numerous sebaeceous glands and hair follicles. Its thick and hair bearing and because it contains numerous sebaceous glands, the scalp is a common site for sebaceous cysts. Source
Bone Of Skull
The skull supports the musculature and structures of the face and forms a protective cavity for the brain. The skull is formed of several bones which, with the exception of the mandible, are joined together by sutures—synarthrodial (immovable) joints. The adult human skull is comprised of twenty-two bones which are divided into two parts of differing embryological origin: the neurocranium and the viscerocranium. Source
The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system. meninges, meninx and meningeal are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system. Source
The innermost layer, the pia mater hugs the spinal cord and brain like a coat. It has blood vessels that deliver oxygen and nutrients to the spinal cord. Source
The arachnoid villi absorb excess cerebrospinal fluid, or CSF, that collects in the venous sinuses surrounding the brain. Acting as one-way valves, the arachnoid villi, or arachnoid granulations, help to ensure that the pressure and volume of CSF surrounding the brain does not reach dangerous levels. Although a cushion of CSF is required to protect the brain from injury, excessive amounts and a buildup of pressure can cause the potentially disabling or fatal condition called hydrocephalus, which is sometimes referred to colloquially as “water on the brain.” The arachnoid villi protrude from the thin second layer that covers the brain, which is called the arachnoid. These small protrusions allow the excess CSF to exit the sinus area and enter the bloodstream. The larger and calcified protrusions are called pacchionian bodies. The majority of the CSF is absorbed by the arachnoid villi that are located in the superior saggital sinus, which is the large central area inside the skull that runs from the front of the head to the back. Under normal conditions, the absorption rate of CSF by the arachnoid villi is similar to the rate of CSF production in the choroid plexus. Source
Superior Sagittal Sinus
Within the human head, is an unpaired area along the attached margin of the falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispheres to the confluence of sinuses. Cerebrospinal fluid drains through arachnoid granulations into the superior sagittal sinus and is returned to venous circulation. Cerebrospinal fluid drains through arachnoid granulations into the superior sagittal sinus and is returned to venous circulation.
This is the anatomic space between the arachnoid mater and the pia mater. It is occupied by spongy tissue consisting of trabeculae (delicate connective tissue filaments that extend from the arachnoid mater and blend into the pia mater) and intercommunicating channels in which the cerebrospinal fluid (CSF) is contained.
Periosteum is an extremely thin region of non-calcified tissue on the exterior of bones. it is a membrane that covers the outer surface of all bones, except at the joints of long bones. Periosteum consists of an outer fibrous connective tissue layer and an inner osteogenic layer. The fibrous layer is made of dense irregular connective tissue containing many strong collagen fibers and fibroblast cells. Fibroblasts produce the collagen fibers and regenerate the fibrous layer as it wears down over time or is injured by stress to the body. The osteogenic layer contains many stem cells and osteoblast cells lining the surface of the osseous tissue that makes up the hard part of the bone. Osteoblasts absorb calcium to form the mineral matrix of solid bone. The fibrous layer of the periosteum plays a vital role in connecting bones to the rest of the body. The collagen fibers of the periosteum not only wrap the entire bone, but also merge with the collagen fibers of the ligaments, joint capsules, and tendons that connect to the bone. Thus, a continuous mass of collagen runs from each bone’s surface, across joints through ligaments and joint capsule to the neighboring bones. Likewise, collagen extends from the periosteum into tendons; extends around and through muscles as the muscular fascia; recollects as another tendon; and inserts on another bone. Periosteum also plays an important role in bone growth and maintenance. Throughout life, bones are constantly being remodeled to adjust their size and thickness to the demands of the body and the availability of calcium to form bone. As bones grow larger, most of this growth is produced by osteoblast cells in the periosteum, which absorb calcium ions from the blood and produce hard mineral matrix. When bones fracture or are damaged microscopically by stress, the osteoblasts of the periosteum repair this damage and replace the mineral matrix, often reinforcing the bone beyond its original thickness. Source
This is a reaction, is a pattern of one or more concentric shells of new bone over a lesion (injury to bone).
The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord. The arachnoid mater is a derivative of the Neural crest mesectoderm in the embryo.
Blood vessels are flexible tubes that carry blood, associated oxygen, nutrients, water, and hormones throughout the body. Blood vessels consist of arteries, arterioles, capillaries, venules, and veins. Vessel networks deliver blood to all tissues in a directed and regulated manner. Blood vessels are key components of the systemic and pulmonary circulatory systems that distribute blood throughout the body. There are three major types of blood vessels: arteries that carry blood away from the heart, branching into smaller arterioles throughout the body and eventually forming the capillary network. The latter facilitates efficient chemical exchange between tissue and blood. Capillaries in turn merge into venules, then into larger veins responsible for returning the blood to the heart. The junctions between vessels are called anastomoses.
This (epiarachnoid space) is a potential space that exists between the meningeal layer of the dura mater and the inner arachnoid mater of the leptomeninges which are adherent to each other. Source
The falx cerebri is the largest of the four main folds (or septa) of the intracranial dura mater, separating the cerebral hemispheres. The falx cerebri is also known as the cerebral falx, named from its sickle-like form. It is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres of the human brain. Calcification of the falx cerebri is more prevalent in older patients, often without a determinable cause, and without pathogenic symptoms. Source