Question

give detail description of the anatomy of brain

Answer 1

The brain is the most important part of human body .

Weight - 2.7 pound in female and 3 pound in male.

Brain is the part of nervous system (central nervous system ; it also includes spinal cord).

Cells forming brain are -

Glial cells - Provide support , nutrition and Homoeostasis , facilitate the signal transmission.

Neurons - They are the main structure of nervous system responsible for reception and transmission of signals.

Bony structure surrounding the brain also called as skull cap is cranium. It protects brain.

The brain is composed of three layers which are found between brain and cranium which are called as meninges -

1)Dura mater - It has two layers periosteum (outermost) and dura(innermost). The dura forms two special folds namely falx and tentorium.falx forms the right and left half of the brain and the tentorium forms the upper and lower parts of the brain.

2) Arachnoid - It's thin and delicate membrane along with blood vessels covering the entire brain. The subdural space is present between dura mater and arachnoid membrane .

3)Pia mater - This is innermost layer covering the brain and is in proximity with the delicate brain.It has numerous blood vessels supplying brain . The subarachnoid space is present between pia mater and Arachnoid mater which contains CSF (Cerebrospinal fluid).

The CSF is thin, Watery and colourless fluid which serves as cushion for brain and spinal cord from any injury. It circulates within hollow chambers of the brain called as ventricles.The chroid plexus maintains the production and absorption of CSF in the ventricles.

The ventricular sysytem is present in four cavities called as ventricles connected with ducts and formens.

Two ventricles which are enclosed in the cerebral hemispheres are called as lateral ventricles(1st and 2nd ventricles). Through foramen of monro both of them connects to third ventricle separately. The Aqueduct of Sylvius connects third and fourth ventricles.

The components of brain -

Brainstem - It is the lower extension of brain which is present in front of cerebellum and connected to spinal cord .It contains three parts - midbrain , pons and medulla oblongata. The main function is as a relay centre to pass information to and from the brain from different parts.

Cerebrum - Forms the major function of the brain which is divided into two parts left and right Cerebra hemispheres which is divided by great longitudinal fissure .These both sides of the brain are joined at the base by corpus callosum.

The cerebral cortex is also called as grey mater as it appears greyish brown in colour.The brain has grooves which is called as gyri and in between gyri is sulcus.Beneath the cerebral cortex the connecting neurons forms the white matter. The brain is divided into lobes -

Frontal lobes - it is located at the front side of the brain and controls various functions and forms prefrontal & premotor cortex , broca's area(for speech).

Occipital lobe- Located at the back side of the brain . This lobe is primarily involved in visual activity.

Parietal lobe - This lobe lnterpret signals received from other areas of brain and provide meaning to the objects.

Temporal lobe - They are located on each side laterally and are responsible for memory and facial recognition, understanding the language.

Limbic system is useful in emotional interpretation. Pineal gland regulates the circadian rhythm of the body .

Cerebellum- Beneath the occipital lobe at the back of the brain cerebellum is located.It is seperated from cerebrum by tentorium. It has main function in balancing and fine activities.

Hypothalamus - It controls parasympathetic nervous system and regulates the secretion of hormones by Pituitary which is extended fron the hypothalamus downwardly. Pituitary is present at the base of brain in sella turcica cavity.

The 12 pairs of nerves originates from the brain which are as follows -

1)Olfactory: Smell
2)Optic: Visual fields and ability to see
3)Oculomotor: Eye movements; eyelid opening
4)Trochlear: Eye movements
5)Trigeminal: Facial sensation
6)Abducens: Eye movements
7)Facial: Eyelid closing; facial expression; taste sensation
8)Auditory/vestibular: Hearing; sense of balance
9)Glossopharyngeal: Taste sensation; swallowing
10)Vagus: Swallowing; taste sensation
11)Accessory: Control of neck and shoulder muscles
12)Hypoglossal: Tongue movement