define Brain
forebrain
midbrain
hindbrain
Answers
an organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating centre of sensation and intellectual and nervous activity.
the anterior part of the brain, including the cerebral hemispheres, the thalamus, and the hypothalamus.
Midbrain, also called mesencephalon, region of the developing vertebrate brain that is composed of the tectum and tegmentum. The midbrain serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing.
the lower part of the brainstem, comprising the cerebellum, pons, and medulla oblongata
Answer :
The brain lies within the skull, or the cranium. It is covered by three membranous layers called meninges . Between the meninges and inside the brain is a fluid called cerebrospinal fluid (CSF) that cushions the brain against shocks . It also helps distribute nutrients and other chemicals to the neurons of the brain and collects waste from them . It provides the neurons some protection from infection .
The brain is divided into three parts the forebrain , midbrain and hindbrain .
The Forebrain :
This is the anterior part of the brain . The cerebrum forms the largest part of the forebrain, or rather of the entire brain . it is divided into two halves - the right and left cerebral hemispheres . The cerebral hemispheres are shaped somewhat like Kidneys, and or partially separated from each other by a deep groove . their outer surface is full of folds , which increase the surface area and help accommodate the maximum number of neurons . The cell bodies of most of the neurons are located in the upper layers of the cerebral hemispheres, giving these layers a greyish appearance . So, the cell bodies are called grey matter . The axons mostly myelinated of these neurons form bundles that appear white, and are thus called white matter . White matter is mostly found in the deeper parts of the cerebrum . The interior of the cerebrum has interconnected cavities called ventricles that are filled with cerebrospinal fluid .
The cerebrum is the centre of Intelligence . Different areas of the cerebrum or concerned with learning, memory emotion and reasoning other areas co-ordinate our voluntary activities and make us feel sensation like pain and heat and also control speech and the Census of touch, smell , sight , hearing and taste.
The hypothalamus a small area of the fore brain is linked to the pituitary gland it controls the endocrine system it also controls many emotional reactions like fear and anger .
The midbrain :
The small region connects the fore brain with the hind brain and spinal cord. It also controls the eye adjustments we need to make in order to see .
The Hindbrain :
This is the posterior part of the brain and is located below the forebrain . It consists of the cerebellum, pons and medulla oblongata . the cerebellum smaller than the cerebrum and is located below it towards the back of the skull . the surface of the cerebellum as a large number of thinely spaced parallel grooves, unlike the irregular folds of the cerebrum . the cerebellum, too is made up of a large number of neurons . The upper layer , while the white matter is buried deeper within the structure . A fourth ventricle, filled with cerebrospinal fluid, lies between the cerebellum and the upper part of the medulla oblongata it is connected to the third ventricle , through a thin duct. The cerebellum coordinates our movements , both voluntary and involuntary . It maintains the bodies posture and balance, and helps us learn new movements .
the Pons lies just about the medula oblongata . It relays information from the fore brain to the cerebellum . It also helps control functions such as sleep, breathing, swallowing, bladder function, hearing, taste, eye moment, facial expressions, facial sensation, balance and posture .
The medulla oblongata lies in front of the cerebellum, at a slightly lower level, and connects to the spinal cord . It controls involuntary actions, such as Heartbeat breathing, sneezing, coughing, swallowing, vomiting , movements of the alimentary canal and secretion by glands . The midbrain, pons and medulla oblongata together make up the brain stem .
Hope it helps you...