The human brain controls nearly every aspect of the human body ranging from physiological functions to cognitive abilities. It functions by receiving and sending signals via neurons to different parts of the body. The human brain, just like most other mammals, has the same basic structure, but it is better developed than any other mammalian brain.
The Human Brain.
On average, an adult brain weighs between 1.0 kg – 1.5 kg. It is mainly composed of neurons – the fundamental unit of the brain and nervous system. Recent estimates have suggested that the brain contains anywhere between 86 billion to 100 billion neurons.
The brain, along with the spinal cord, constitutes the central nervous system. It is responsible for thoughts, interpretation and origin of control for body movements.
Brain Diagram
The brain diagram given below highlights the different lobes of the human brain.
Parts of Human Brain
Following are the major parts of the human brain:
Forebrain – Largest part of the brain
It is the anterior part of the brain. The forebrain parts include:
- Cerebrum
- Hypothalamus
- Thalamus
Forebrain Function: Controls the reproductive functions, body temperature, emotions, hunger and sleep.
Fact: The largest among the forebrain parts is the cerebrum. It is also the largest part of all vertebrate brains.
Midbrain: Smallest and central part of the brain.
The midbrain consists of:
- Tectum
- Tegmentum
Hindbrain: The lower part of the brain.
The hindbrain is composed of:
- Cerebellum
- Medulla
- Pons
Cerebrum
The cerebrum is the largest part of the brain. It consists of the cerebral cortex and other subcortical structures. It is composed of two cerebral hemispheres that are joined together by heavy, dense bands of fibre called the corpus callosum. The cerebrum is further divided into four sections or lobes:
Frontal lobe: It is associated with parts of speech, planning, reasoning, problem-solving and movements.
Parietal lobe: Help in movements, the perception of stimuli and orientation.
Occipital lobe: It is related to visual processing.
Temporal lobe: This region is related to perception and recognition of memory, auditory stimuli and speech.
Cerebrum Function
The cerebrum is responsible for thinking, intelligence, consciousness and memory. It is also responsible for interpreting touch, hearing and vision.
Thalamus
The thalamus is a small structure, located right above the brain stem responsible for relaying sensory information from the sense organs. It is also responsible for transmitting motor information for movement and coordination. Thalamus is found in the limbic system within the cerebrum. This limbic system is mainly responsible for the formation of new memories and storing past experiences.
Hypothalamus
The hypothalamus is a small and essential part of the brain, located precisely below the thalamus. It is considered the primary region of the brain, as it is involved in the following functions:
- Receives impulses
- Regulates body temperature
- Controls the mood and emotions
- Controls the sense of taste and smell
- Synthesises the body’s essential hormones
- Coordinates the messages from the autonomous nervous system
- Controls appetite, peristalsis, the rate of heartbeat, and blood pressure
- Forms an axis with the pituitary gland which is the main link between the nervous and the endocrine systems
Tectum
The tectum is a small portion of the brain, specifically the dorsal part of the midbrain. It serves as a relay centre for the sensory information from the ears to the cerebrum. It also controls the reflex movements of the head, eye and neck muscles. It provides a passage for the different neurons moving in and out of the cerebrum.
Tegmentum
Tegmentum is a region within the brainstem. It is a complex structure with various components, which is mainly involved in body movements, sleep, arousal, attention, and different necessary reflexes. It forms the platform for the midbrain and connects with the thalamus, cerebral cortex and the spinal cord.
Cerebellum
The cerebellum is the second largest part of the brain, located in the posterior portion of the medulla and pons. The cerebellum and cerebrum are separated by cerebellar tentorium and transverse fissure. Cortex is the outer surface of the cerebellum, and its parallel ridges are called the folia. Apart from this, the cerebellum has the cerebellar peduncles, cerebellar nuclei, anterior and posterior lobes. The cerebellum consists of two hemispheres, the outer grey cortex and the inner white medulla. It is mainly responsible for coordinating and maintaining the body balance during walking, running, riding, swimming, and precision control of the voluntary movements. The main functions of the cerebellum include:
Medulla Oblongata
The medulla oblongata is a small structure present in the lowest region of the brain. It mainly controls the body’s autonomic functions such as heartbeat, breathing, and digestion. It plays a primary role in connecting the spinal cord, pons and the cerebral cortex. Also, it helps us in maintaining our posture and controlling our reflexes.
Pons
The pons is the primary structure of the brain stem present between the midbrain and medulla oblongata. It serves as a relay signals between the lower cerebellum, spinal cord, the midbrain, cerebrum and other higher parts of the brain.
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