CNS.pptx Central nervous system meninges ventricles of brain it's structure and functions of brain
1. Central nervous system:
Meninges, Ventricles parts
of Brain and CSF
AISHWARYA AKSHAY P
LECTURER
MARGADARSHAN COLLEGE OF
PHARMACY-ILKAL
2. Meninges
The brain and spinal cord are completely surrounded by three
membranes, the meninges.
It lying between the skull and the brain and between the vertebrae
of the spinal cord.
They are;
1. Dura mater
2. Arachnoid mater
3. Pia mater
5. Dura mater
Topmost layer
It connects the meninges to the skull and
vertebral column.
It is composed of tough, fibrous connective tissue.
It consist of two layers ;
Periosteal layer: it is connects the dura mater to the skull and covers the
meninges layer.
Inner meningeal layer: considered the actual dura mater
It divide the cranial cavity into different compartments.
6. Falx cerebri (Cerebral Hemisphere)
Falx cerebelli ( Cerebellar Hemisphere)
Tentorium cerebelli (Cerebrum-Cerebellum)
In between Periosteal layer and inner meningeal layer a Dural
venous sinuses is present, which means these veins drain blood
from the brain to heart through internal jugular veins.
8. Arachnoid mater
This middle layer of the meninges connects the dura mater and pia mater.
It covers the brain and spinal cord.
Subdural space: Space between the dura and the arachnoid mater, containing a thin layer
of serous fluid
Subarachnoid space: Space between arachnoid and pia mater. Its filled with CSF.
Membrane projections from the arachnoid mater called arachnoid granulation.
It extends from subarachnoid space to the dura mater.
Arachnoid granulations remove CSF from the subarachnoid space and send it to the dural
venous sinuses, where it reabsorbed into venous system.
9. Pia mater
Thin, inner layer of the meninges.
Directly contact with the cerebral cortex and spinal cord.
The pia mater has a rich supply of blood vessels, which provide nutrients to
nervous tissue.
Pia mater contains the choroid plexus, a network of capillaries and
ependymal cells that produce cerebrospinal fluid.
These are located within the cerebral ventricles.
11. Protection : It is a protective barrier around the brain and spinal cord,
shielding them from physical injury and pathogens.
13. Ventricles of brain
Within the brain there are four irregular shaped cavities, or
ventricles containing cerebrospinal fluid( CSF).
They are:
1. Right lateral ventricles
2. Left LV
3. Third ventricle
4. Fourth ventricle
15. The lateral ventricles
These cavities lie within the cerebral hemispheres, one on
each side of the median plane just below the corpus callosum
They communicate with the third ventricle by interventricular
foramina.
16. Third ventricles
The third ventricle is a cavity situated below the lateral
ventricle between the two parts of the thalamus
It communicates with the fourth ventricle by a canal, the
cerebral aqueduct of the midbrain.
17. Fourth ventricle
The fourth ventricle is a diamond shaped cavity situated
below and behind the third ventricle, between the
cerebellum and pons.
It is continuous below with the central canal of the spinal
cord and communicates with the subarachnoid space
by foramina in its roof.
19. Cerebrospinal fluid
CSF, or cerebrospinal fluid, is a clear, watery fluid that surrounds and protects the brain and spinal
cord. It protecting these vital structures from injury, and also plays a role in nutrient delivery and
waste removal.
CSF circulates within the ventricles (hollow cavities) of the brain, and around the brain and spinal
cord in the subarachnoid space.
Functions:
Protection: It cushions the brain and spinal cord, protecting them from sudden impacts and injuries.
Nutrient Delivery: CSF delivers nutrients to the central nervous system.
Homeostasis: CSF helps maintain a stable environment for the central nervous system.
Production and Circulation:
CSF is produced primarily by the choroid plexus in the ventricles of the brain. It is continuously
produced, circulated, and absorbed.
21. Structure of Brain
On average, an adult brain weighs between 1000gms-1500gms.
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.
The brain is enclosed within the skull, which provides frontal, lateral and dorsal protection.
The skull consists of 22 bones, 14 of which form the facial bones and the remaining 8 form
the cranial bones.
Anatomically, the brain is contained within the cranium and is surrounded by the
cerebrospinal fluid.
22. 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.
Midbrain: Smallest and central part of the brain
The midbrain consists of:
Tectum
Tegmentum
23. Hindbrain: The lower part of the brain
The hindbrain is composed of:
Cerebellum
Medulla
Pons
Hindbrain functions:
The three regions of the hindbrain coordinates all processes necessary for survival. These
induce breathing, heartbeat, sleep, wakefulness and motor learning.
24. Cerebrum
It’s the largest part of your brain, divided into two halves:
the left and right hemispheres.
The two halves connect by nerve fiber bundles
(white matter) called the corpus callosum.
Your cerebrum interprets your five senses.
It regulates conscious actions that require thinking,
like your speech, memory, behavior, personality,
movement, reasoning and judgment.
25. 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.
26. Hypothalamus:
Just below your thalamus, the hypothalamus regulates
hormones and autonomic functions like hunger and thirst.
Thalamus:
Sitting above your brainstem, this is the switchboard to
your central nervous system.
It relays sensory information to your cerebral cortex
from the rest of your body.
28. Cerebellum
Second largest portion of the brain
Located beneath the posterior part
of the cerebrum
A deep grooves known as transverse fissure
separates cerebrum to cerebellum,
The external surface of cerebellum, called
cerebellar cortex, look like butterfly, constricted
area called vermis.
May play a role in learning from experiences
and language processing.
It will produce fluid limb or body movements.
29. It senses equilibrium.
Transfers information.
Coordinates eye movement.
It enables precision control of the voluntary body movements.
Predicts the future position of the body during a particular movement.
Both anterior and posterior lobes are concerned with the skeletal movements.
The cerebellum is also essential for making fine adjustments to motor actions.
Coordinates and maintains body balance and posture during walking, running,
riding, swimming.
30. Brain stem
The brain stem is the posterior stalk like
part of the brain that connects the cerebrum
with the spinal cord.
In the human brain stem composed of
midbrain, pons and medulla oblongata.
Midbrain:
It extends from the pons about 2.5 cm long.
It associated with vision, hearing, motor
control, sleep/wake, alertness and temperature regulation.
Posterior part called as Tectum.
31. 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.
The main functions of the pons include:
Controlling sleep cycles.
Regulating the magnitude and frequency of the respiration.
Transfers information between the cerebellum and motor cortex.
Pons is also involved in sensations, such as the sense of taste, hearing
and balance.
32. Medulla oblongata
Lowermost part of the brain stem and continuation of the superior
portion of spinal cord.
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.
33. It plays an essential role in passing messages between your spinal
cord and brain
It regulates blood pressure and responsible for maintaining basic
rhythm of breathing.
Others- Vomiting, swallowing, cough, hiccupping and sneezing etc
5 pairs of cranial nerves originates from the nuclei located in medulla
oblongata.
