- It does not initiate movement, but contributes
to coordination, precision, and accurate
timing. It receives input from sensory systems
of the spinal cord and from other parts of the
brain, and integrates these inputs to fine-tune
motor activity.
- Cerebellar damage produces disorders in fine
movement, equilibrium, posture, and motor
learning in humans.
- Cerebral cortex called grey matter is on the
outside, comprising of three layers of cells.
Within this thin layer are several types of
neurons with a highly regular arrangement,
the most important being Purkinje cells and
granule cells and the white matter lies inside.
- Functions: (a) It co-ordinates muscular body
movement.
(b) It controls reflex action of skeletal muscle
activities.
II. Pons Varolii:
- It is situated in front of cerebellum and above
the medulla oblongata and joins medulla
oblongata with the mid brain. Its fibre is of
white matter.
- This region of the brainstem includes neural
pathways or tracts that conduct signals from
the brain down to the cerebellum and medulla,
and tracts that carry the sensory signals up into
the thalamus.
- The pons in humans measures about 2.5
centimetres (0.98 in) in length. Most of it
appears as a broad anterior bulge rostral to
the medulla. Posteriorly, it consists mainly
of two pairs of thick stalks called cerebellar
peduncles. They connect the cerebellum to the
pons and midbrain.
- The pons contains nuclei that relay signals
from the forebrain to the cerebellum, along
with nuclei that deal primarily with sleep,
respiration, swallowing, bladder control,
hearing, equilibrium, taste, eye movement,
facial expressions, facial sensation and
posture.
III. Medulla Oblongata:
- It is the posteriormost part and connects the
spinal cord and various parts of the brain.
- The medulla of the brain is connected to the
spinal cord. The medulla contains centres
which control respiration, cardiovascular
reflexes and gastric secretions.
- This brain stem controls various reflexes like
breathing, salivation, chewing, coughing,
sneezing, etc.
Ventricles of the Brian and Cerebrospinal
Fluid
The ventricles consist of four hollows,
fluid filled spaces inside the brain. A lateral
ventricle lies inside each hemisphere of the
cerebrum. Each lateral ventricle is connected
to the third ventricle by an interventricular
Foramen (formen of Monro). The third
ventricle consists of a narrow channel
between the hemispheres through the area of
the thalamus. It is connected by the cerebral
aqueduct or aqueduct of sylvius or iter in the
midbrian portion of the brain stem to the fourth
