all about the brain

HUMAN BRAIN
The brain is one of the largest and most complex organs in the human body. It is made up of more than 100 billion nerves that communicate in trillions of connections called synapses. The human brain is the command centre for the human nervous system. It receives input from the sensory organs and sends output to the muscles.

Parts of the Human Brain

Ventricles are the 4 cavities in the brain.
• The ventricles of the brain are a communicating network of cavities filled with cerebrospinal fluid (CSF) produced by choroid plexus.
• CSF is the tissue fluid of the central nervous system (CNS).
• (CSF) bathes and cushions the brain and spinal cord within their bony confines. • CSF is produced by modified ependymal cells of the choroid plexus found in all components of the ventricular system except for the cerebral aqueduct and the posterior and anterior horns of the lateral ventricles.

Runs from the spinal chord to the pons (a broad mass of chiefly transverse nerve fibers)

a. Cardiac center – regulate heart rate
b. Vasomotor center – regulate diameter of blood vessels thereby blood
c. Respiratory center – regulate breathing d. Pressure
e. Reflex center – for coughing, sneezing, swallowing, and vomiting Pons (bridge) is where two respiratory centers are lodge in which works with those in the medulla to regulate breathing.

Midbrain runs from the pons to the hypothalamus enclosing the cerebral aqueduct which is the tunnel connecting the 3rd and 4th ventricles. The midbrain helps to relay information for vision and hearing.

It regulates several reflexes:
• Visual reflex
• Auditory reflex
• Righting reflex

Cerebellum (Latin for little brain) is a region of the brain that plays an important role in motor control.
The cerebellum is at the base and the back of the brain. The cerebellum is responsible for coordination and balance. It functions below the level of conscious thought which is why it regulates involuntary movements.
It regulates movement such as coordination, regulation of muscle tone, appropriate trajectory and endpoint of movements and maintenance of posture and equilibrium.

Hypothalamus is a region of the forebrain below the thalamus that coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity.
a.
b.
c.
d.
e.
f.
g.

Brainstem

Produces antidiuretic hormone (ADH)
Produces releasing hormones
Regulates body temperature
Regulates food intake
Integrates functioning of the ANS
Regulates body rhythms
Stimulates visceral response during emotional situations

Thalamus means “inner room” in Greek, as it sits deep in the brain at the top of the brainstem. The thalamus is called the gateway to the cerebral cortex, as nearly all sensory inputs pass through it to the higher levels of the brain.
It also regulates mostly sensations, may also suppress unimportant sensations, also involved in alertness, awareness and may contribute also to memory.
It also relays sensory signals to the cerebral cortex and controls sleep and a wake states. It is positioned between the mid-brain and the fore-brain.

Cerebrum, Latin for “brain” the biggest part of the brain which is made of
2 hemispheres (left & right). Located at its base is corpus callosum which is a deep groove

It is here that things like perception, imagination, thought, judgment, and decision occur.
The surface of the cerebrum, the cerebral cortex which is a gray matter(made up of cell bodies of neurons, which sit on top of a large collection of white matter pathways.
The convolutions have "ridges" which are called gyri (singular: gyrus), and "valleys" which are called sulci (singular: sulcus). Some of the sulci are quite pronounced and long, and serve as convenient boundaries between four areas of the cerebrum called lobes.

Basal ganglia are pair of gray matter inside the white matter of cerebral hemispheres. The basal ganglia are a cluster of structures in the center of the brain. The basal ganglia coordinate messages between multiple other brain areas. • The frontal lobes are responsible for problem solving and judgment and motor function.
• The parietal lobes manage sensation, handwriting, and body position.
• The temporal lobes are involved with memory and hearing.
• The occipital lobes contain the brain's visual processing system.

The brain is surrounded by a layer of tissue called the meninges. The skull (cranium) helps protect the brain from injury.

Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord. In humans, there are traditionally twelve pairs of cranial nerves (although an additional anterior pair of nerves, numbered 0, also exists). The first three pairs (including nerve 0) emerge from the cerebrum; the remaining ten pairs emerge from the brainstem.

DIVISIONS OF AUTONOMIC NERVOUS SYSTEM (ANS)