If you want to learn about the human brain, you have come to the right place, because in this article we have shared all the information related to the human brain. Let’s read and understand the complete details of the human brain in detail.
The human brain is enclosed within the skull called the cranium, which protects it from external injuries. The brain is regarded as the main part of the central nervous system. The fully developed human brain constitutes approximately 1/50th of the body’s weight and is situated within the cranial cavity. The total weight of the brain is about 1400 grams, and it is safely housed inside the skull made up of 8 bones.
During the early stages of development, the brain is divided into three parts.
1. Forebrain (Prosencephalon Brain)
This is the largest part of the forebrain, and it helps humans recognize sensations related to smell, odor, taste, and olfaction. The forebrain assists in identifying the sensory inputs listed above.
The part of the forebrain, which makes up about two-thirds of the entire brain, forms a protective covering over the midbrain and hindbrain. It contains approximately 200 million nerves (sensory) called the corpus callosum.
It has two main parts:
(a) Cerebrum
This makes up about two-thirds of the brain. It is divided into right and left hemispheres by a longitudinal fissure. The entire surface of each hemisphere is folded into numerous ridges and grooves. The outer part of the cerebrum, called the cortex, contains nerve cells and their dendrites. The inner white matter contains axons of nerve cells.
Functional areas of the cerebrum include:
(b) Diencephalon
Also called the posterior part of the forebrain, it is located below the cerebrum.
It has the following two parts:
1. Thalamus — Located just below the corpus callosum in each hemisphere and between the thalamic nuclei and lateral ventricles, the thalamus is an oval-shaped cluster of nerve cells and fibers. It functions as a critical relay center between the cerebral cortex and spinal cord. The thalamus sorts incoming sensory impulses and transmits them to the cerebral cortex.
Functions of the Thalamus: It recognizes pain, cold, and heat.
2. Hypothalamus — Located beneath and in front of the thalamus, just above the pituitary gland, it is composed of nerve cells and forms the floor and posterior wall of the third ventricle.
Functions of the Hypothalamus:
2. Midbrain / Mesencephalon (Brain)
It is located between the hypothalamus of the forebrain and the pons of the hindbrain. The midbrain is a small part of the brain that forms the upper part of the stem.
It contains many groups of nerves that assist in maintaining balance and coordination of the body’s organs, as well as controlling eye muscles and equilibrium within the brain. This brain also regulates internal involuntary functions and habitual activities.
It has two main parts:
(a) Corpora Quadrigemina
It is a small tubular part located between the forebrain and hindbrain, also called the mesencephalon. The mesencephalon (midbrain) is made up of four ovals, called the corpora quadrigemina. The upper two oval bodies are called the Tectum, and the lower two are called the Tegmentum. The tectum is responsible for vision, and the tegmentum for hearing. Functions of corpora quadrigemina – It is the center for controlling vision and hearing.
(b) Cerebral Peduncle
The cerebral peduncles are stalk-like structures located on the ventral surface. On the dorsal surface of the corpora quadrigemina, there are four rounded bulges. These are divided into two pairs: the superior colliculi and the inferior colliculi. The superior colliculi are involved in the process of seeing objects, while the inferior colliculi are involved in hearing. Near the cerebral peduncles, there is a red nucleus. The pineal gland is situated between the superior colliculi.
Functions of the cerebral peduncle:
3. Hindbrain (Rhombencephalon)
This is the posteriormost part of the brain, connected to the spinal cord via the medulla. The body’s skull (atlas vertebra) provides support for the entire head.
The hindbrain has three main parts:
(a) Pons
Located anterior to the midbrain and below the midbrain, above the medulla oblongata. It is the middle part of the brainstem. Its basal part is called the middle cerebellar peduncle. Nerve fibers for sensory and motor functions pass through this area, connecting the forebrain with the midbrain and medulla oblongata.
(b) Cerebellum
This is the second-largest part of the brain, situated below the cerebrum. It contains many folds. Its cortex is made of gray matter. The cerebellum maintains body balance and coordinates muscular activities.
Functions of the cerebellum:
(c) Medulla Oblongata
This is the lowest part of the brainstem, located above the spinal cord and below the pons. It is tube-shaped, about 2.5 cm long, with a slightly swollen upper part. It is situated in the posterior cranial fossa and connects to the spinal cord just below the foramen magnum of the occipital bone. Its outer part is made of white matter and the inner part of gray matter. It contains cardiac and respiratory centers that regulate heartbeat and breathing. It also has centers for sleep, wakefulness, and salivation.
Functions of the medulla oblongata:
The cerebellum or hindbrain (Cerebellum):
The cerebellum: It is a protruded part located at the back and below the occipital lobe of the cerebrum, situated above the medulla oblongata and behind the pons, covering the dorsal surface of the brain hemisphere. The cerebellum is divided into two hemispheres, connected by a median band called the vermis. It has gray matter on the outside and white matter inside.
Cerebellar cortex: It is thinner than the cerebral cortex. The cerebellum accounts for about one-tenth of the total brain weight.
Cerebellar nuclei: They are located deep within the white matter and are connected to other parts of the brain via superior cerebellar peduncles, middle cerebellar peduncles, and inferior cerebellar peduncles, linking to the midbrain, pons, and medulla oblongata, respectively.
The cerebellum coordinates voluntary muscles and maintains body posture and balance. It constantly receives sensory impulses related to tension in muscles, joint positions, and information from the cerebral cortex.
The midbrain, pons, and medulla oblongata share common functions, and together they are called the brain stem.
Nuclei are present in this area, from where cranial nerves emerge.
What are the meninges (Meninges)?
The meninges are protective membranes that lie between the skull and the brain, completely covering the spinal cord (spinal cord) and preventing injuries. There are three types of meninges.
They are arranged from outside to inside in the following manner:
1. Dura mater
The outermost covering (membrane) of the dura mater is made of dense, tough connective tissues. It has two layers: the outer layer lines the inner surface of the skull and forms the periosteum. This layer continues over the skull’s external surface where it extends as the periosteum at the foramen magnum. Its internal layer is sometimes raised inward in certain places, forming a double layer that separates parts of the brain and helps maintain their position.
This gives rise to four cerebral sinuses and four venous rings. The falx cerebri is a ring that lies between the two cerebral hemispheres. Its upper end forms the superior longitudinal or sagittal sinus, which supplies blood from the brain. Its lower end forms the inferior longitudinal sinus, which drains blood from the brain. The tentorium cerebelli is a venous ring located between the cerebrum and cerebellum. Three sinuses are formed from this ring. The falx cerebri is a ring located between the two cerebral hemispheres. The diaphgramatic suture of the sphenoid bone forms a roof over the sella turcica, where the pituitary gland is situated, connected above to the hypothalamus.
2. Arachnoid mater
This is a thin, delicate membrane situated just beneath the dura mater, made of fibrous and flexible tissues. It is separated from the dura mater by a narrow subdural space. Between the arachnoid and pia mater, there is the subarachnoid space. From arachnoid to pia mater, through tiny trabeculae, extending into the subarachnoid space, cerebrospinal fluid (CSF) is present, which protects the brain and spinal cord from injuries.
3. Pia mater
The pia mater is the membrane below the arachnoid. It is a thin membrane of connective tissue with many blood vessels (highly vascular). It remains in contact with the surface of the brain and spinal cord, covering all their convolutions and dipping into every fissure.
The organization of cerebrospinal fluid is as follows:
In addition, it contains potassium, calcium, sodium, uric acid, sulfate, phosphate, and creatinine.
We hope you liked the information about the human brain.
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