Telencephalon , or a great brain , is divided by a longitudinal (central) furrow into two cerebral hemispheres - the left and right (diagram 151), w

Telencephalon structure

Telencephalon, or a great brain, is divided by a longitudinal (central) furrow into two cerebral hemispheres — the left and right (diagram 151), which are interconnected by a corpus callosum. On the top hemispheres are covered with a crust formed by a gray matter. Thickness of a hemisphere is formed by a white matter, where several subcortical nuclei are located. In the middle of each hemisphere there is a ventricle.

Brain liquid — CSF (diagram 152), which is contained in the brain ventricles, spinal canal and between the meninges, — reduces and distributes excess mechanical forces that may damage the brain. An adult has 100-150 ml of CSF. However, only 20-40 ml is contained in the ventricles, and the main part — between soft and arachnoid brain meninges. Liquor is produced constantly in the walls of the capillaries of the brain ventricles from the blood plasma. Its surplus gets into the venous system of the dura mater. Liquor is an internal brain environment that provides support for its salt composition, the osmotic pressure, delivers oxygen and nutrients to the brain cells, ensures removal of metabolic waste products.

Hemispheres have an uneven surface with sinuous ridges — the convolutions and slot grooves — grooves, which significantly increases their surface. Each hemisphere is divided by large furrows into four parts: frontal, occipital, parietal and temporal lobe (diagram 151).

Diagram 153. The layers of neurons in the cerebral cortex. Cells of the 5th layer are called the motor giant pyramidal cells (Betz cells): a) circuit; b) species under the microscope

The cerebral cortex has a thickness of 3-5 mm, and its total area due to fissures and convolutions is 1400 — 1600 cm2. Microscopic structure of the cerebral cortex was first investigated by Ukrainian scientist Vladimir Betz. Neurons in the cerebral cortex have six layers. Each layer, except the first, which is formed by short spikes of the nerve cells, consist of certain type neurons (diagram 153). Taken from http://worldofschool.org

Diagram 151. The structure of the brain: a) top view: 1 — the right hemisphere; 2 — the left hemisphere; 3 — the central sulcus; 4 — furrow; 5 — gyrus; b) longitudinal section: 6 — frontal lobe; 7 — the parietal lobe; 8 — occipital lobe; 9 — the temporal lobe; 10 — the cerebellum; 11 — the medulla oblongata; 12 — an intermediate brain; 13 — midbrain; 14 — bridge; 15 — the corpus callosum; 16 — ventricle
Diagram 152. The circulation of cerebrospinal fluid in the brain and spinal cord. 1 — the skull; 2 — dura; 3 — place fluid education; 4 — the spinal cord; 5 — the central channel; 6 — circulation of the fluid around the spinal cord; 7 — the direction of fluid circulation
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Questions:
  • What is the role of the brain for the human body?

  • Explain the features of the anatomical and microscopic structure of the brain.

  • What role plays brain in regulating physiological processes?