Anatomy of the Brain By Regina Bailey; March 15, 2019
Web link: (https://www.thoughtco.com/anatomy-of-the-brain-373479)
The anatomy of the brain is complex due its intricate structure and function. This amazing organ acts as a control center by receiving, interpreting, and directing sensory information throughout the body. The brain and spinal cord are the two main structures of the central nervous system. There are three major divisions of the brain. They are the forebrain, the midbrain, and the hindbrain.
The forebrain, the midbrain, and the hindbrain are the three main parts of the brain.
The forebrain has two major parts called the diencephalon and the telencephalon. The forebrain is responsible for a number of functions related to thinking, perceiving, and evaluating sensory information.
The midbrain, also called the mesencephalon, connects the hindbrain and the forebrain. It is associated with motor functions and auditory and visual responses.
The hindbrain contains both the metencephalon and the myelencephalon. The hindbrain is associated with balance and equilibrium and the coordination of movement along with autonomic functions like our breathing and our heart rate.
Both the midbrain and the hindbrain make up the brainstem.
Brain Divisions
The forebrain is the division of the brain that is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function. There are two major divisions of forebrain: the diencephalon and the telencephalon. The diencephalon contains structures such as the thalamus and hypothalamus which are responsible for such functions as motor control, relaying sensory information, and controlling autonomic functions. The telencephalon contains the largest part of the brain, the cerebrum. Most of the actual information processing in the brain takes place in the cerebral cortex.
The midbrain and the hindbrain together make up the brainstem. The midbrain or mesencephalon, is the portion of the brainstem that connects the hindbrain and the forebrain. This region of the brain is involved in auditory and visual responses as well as motor function.
The hindbrain extends from the spinal cord and is composed of the metencephalon and myelencephalon. The metencephalon contains structures such as the pons and cerebellum. These regions assists in maintaining balance and equilibrium, movement coordination, and the conduction of sensory information. The myelencephalon is composed of the medulla oblongata which is responsible for controlling such autonomic functions as breathing, heart rate, and digestion.
Anatomy of the Brain: Structures
The brain contains various structures that have a multitude of functions. Below is a list of major structures of the brain and some of their functions.
Basal Ganglia
Involved in cognition and voluntary movement
Diseases related to damages of this area are Parkinson's and Huntington's
Brainstem
Relays information between the peripheral nerves and spinal cord to the upper parts of the brain
Consists of the midbrain, medulla oblongata, and the pons
Broca's Area
Speech production
Understanding language
Central Sulcus (Fissure of Rolando)
Deep grove that separates the parietal and frontal lobes
Cerebellum
Controls movement coordination
Maintains balance and equilibrium
Cerebral Cortex
Outer portion (1.5mm to 5mm) of the cerebrum
Receives and processes sensory information
Divided into cerebral cortex lobes
Cerebral Cortex Lobes
Frontal Lobes -involved with decision-making, problem solving, and planning
Occipital Lobes-involved with vision and color recognition
Parietal Lobes - receives and processes sensory information
Temporal Lobes - involved with emotional responses, memory, and speech
Cerebrum
Largest portion of the brain
Consists of folded bulges called gyri that create deep furrows
Corpus Callosum
Thick band of fibers that connects the left and right brain hemispheres
Cranial Nerves
Twelve pairs of nerves that originate in the brain, exit the skull, and lead to the head, neck and torso
Fissure of Sylvius (Lateral Sulcus)
Deep grove that separates the parietal and temporal lobes
Limbic System Structures
Amygdala - involved in emotional responses, hormonal secretions, and memory
Cingulate Gyrus - a fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior
Fornix - an arching, fibrous band of white matter axons (nerve fibers) that connect the hippocampus to the hypothalamus
Hippocampus - sends memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieves them when necessary
Hypothalamus - directs a multitude of important functions such as body temperature, hunger, and homeostasis
Olfactory Cortex - receives sensory information from the olfactory bulb and is involved in the identification of odors
Thalamus - mass of gray matter cells that relay sensory signals to and from the spinal cord and the cerebrum
Medulla Oblongata
Lower part of the brainstem that helps to control autonomic functions
Meninges
Membranes that cover and protect the brain and spinal cord
Olfactory Bulb
Bulb-shaped end of the olfactory lobe
Involved in the sense of smell
Pineal Gland
Endocrine gland involved in biological rhythms
Secretes the hormone melatonin
Pituitary Gland
Endocrine gland involved in homeostasis
Regulates other endocrine glands
Pons
Relays sensory information between the cerebrum and cerebellum
Wernicke's Area
Region of the brain where spoken language is understood
Midbrain
Cerebral Peduncle
anterior portion of the midbrain consisting of large bundles of nerve fiber tracts that connect the forebrain to the hindbrain
Reticular Formation
Nerve fibers located inside the brainstem and a component of the tegmentum (midbrain)
Regulates awareness and sleep
Substantia Nigra
Helps to control voluntary movement and regulates mood (midbrain)
Tectum
The dorsal region of the mesencephalon (midbrain)
Assists in visual and auditory reflexes
Tegmentum
The ventral region of the mesencephalon (midbrain)
Includes the reticular formation and the red nucleus
Brain Ventricles
Ventricular System - connecting system of internal brain cavities filled with cerebrospinal fluid
Aqueduct of Sylvius - canal that is located between the third ventricle and the fourth ventricle
Choroid Plexus - produces cerebrospinal fluid
Fourth Ventricle - canal that runs between the pons, medulla oblongata, and the cerebellum
Lateral Ventricle - largest of the ventricles and located in both brain hemispheres
Third Ventricle - provides a pathway for cerebrospinal fluid to flow
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