Human Brain: Structure, Diagram, function, diagram, Facts, Functions, Anatomy

What is the Human Brain?

The human brain governs each part of our body, centring our thoughts, emotions, memory, and behaviours. The structure and functions of the brain are so compelling that when understood, we would get overwhelmed by the complexity and huge role it plays in our day-to-day living. Weighing about 1.0 to 1.5 kg, an adult human brain contains approximately 86 billion neurons. The brain, together with the spinal cord, forms part of the central nervous system that controls all activities in the human body, from mere thoughts and body movements to the interpretation of senses.

Location of the Brain

The brain sits in the skull, composed of 22 bones. It is cushioned by CSF, which also provides some immunological protection and suspends the brain to reduce its effective weight.

Structure of the Human Brain

The human brain can be anatomically divided into three main parts: the forebrain, midbrain, and hindbrain. Each part includes specific structures and functions essential in various physiological and psychological processes.

Forebrain

The parts of the forebrain are:

• Cerebrum: The largest part responsible for thinking, intelligence, consciousness, memory, and sensory interpretation.

• Hypothalamus: Body temperature, emotions, hunger, sleep, synthesises some essential hormones

• Thalamus: Relaying sensory and motor information

Midbrain

The parts of the midbrain are:

• Tectum: Conducts sensory information from the ears and controls reflex movements

• Tegmentum: Seems to be concerned with body movements, the process of sleep, arousal and attention

Hindbrain

The parts of the hindbrain are:

• Cerebellum: Coordinates balance of the body and voluntary movements

• Medulla Oblongata: Coordinates autonomic functions such as heartbeat and breathing

• Pons: Acts as a bridge in conduction signals between different parts of the brain and controls sleep cycles and respiratory activities.

Neurons and Synapses

• Neurons are the simplest functional units of the brain, transmitting information through electrical and chemical signals.

• Synapses are interconnections between neurons, facilitating communication within the brain.

Blood Supply & Protection of the Brain

• The carotid and vertebral arteries supply blood to the brain.

• The skull, meninges, and cerebrospinal fluid offer protection to the brain.

Functions of the Human Brain

The functions of the brain have been discussed below:

• The brain controls sensory processing, motor functions, cognition, emotions, and autonomic activities.

• Different regions of the brain have specified functions.

Neuroplasticity – How the Brain Adapts

Neuroplasticity refers to the brain’s ability to reorganize its connections and form new neural pathways in response to learning, experience, or injury.

• The brain can reorganise itself by forming new neural connections.

• Neuroplasticity enables learning, memory, and recovery from brain injuries.

Important Points to Remember (NEET)

• The human brain weighs approximately 1.4 kilograms and contains approximately 86 billion neurons.

• It takes up about 20 per cent of the energy of the whole body while it makes up only 2 per cent of the human body weight.

• The left hemisphere of the brain controls the right side of the human body, and vice versa.

Human Brain NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Phases of action potential

• Factors affecting action potential

Practice Questions for NEET

Q1. The space between the arachnoid and pia mater is known as

1. Subdural space

2. Cerebrospinal fluid

3. Subarachnoid space

4. Subpiamater space

Correct answer: 3) Subarachnoid space

Explanation:

The human brain is located in the cranial cavity of the skull, protected by the cranium. It is surrounded by three layers of membranes called meninges: the tough outer dura mater, the middle arachnoid mater with a network of fibers, and the delicate inner pia mater, which is closely attached to the brain and spinal cord. Between the dura mater and the arachnoid mater lies the subdural space, while the subarachnoid space exists between the arachnoid and pia mater. These spaces, along with the cavities within the brain, are filled with cerebrospinal fluid (CSF), which cushions and protects the central nervous system, facilitates nutrient and waste exchange, and helps maintain constant pressure around the brain.

Hence, the correct answer is option 3) Subarachnoid space.

Q2. The brain is located in the

1. Thoracic cavity

2. Cranial cavity

3. Body cavity

4. Below vertebrae

Correct answer: 2) Cranial cavity

Explanation:

Part of the skull, the cranial cavity is where the brain is situated. It is encircled by layers of membranes known as meninges and cerebrospinal fluid, and it is shielded by the skull's bones. The brain is in charge of regulating vital processes like memory, locomotion, thought, and sensory processing. It is separated into multiple sections, such as the brainstem, cerebellum, and cerebrum.

Hence, the correct answer is option 2)Cranial cavity.

Q3. The grey matter of cerebellum exhibits tree-like structure called

1. Arbor vitae

2. Purkinje cells

3. Basket cells

4. Granule cells

Correct answer: 1) Arbor vitae

Explanation:

Three layers of cells and fibres make up the grey matter that surrounds the cerebellum. Arbor vitae are tree-like structures found in the cerebellar grey matter. Characteristically big flask-shaped Purkinje cells are found in the intermediate layer. Granule cells, basket cells, and Golgi cells are also found in the cerebellum.

Therefore, the grey matter of the cerebellum exhibits a tree-like structure called arbour vitae.

Hence, the correct answer is option 1) Arbor vitae.

Also Read:

• MCQs on Human Brain

• Lobes of Cerebrum

• Autonomic Nervous System

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