In this presentation there is brief description of the Meninges and the Cerebrospinal fluid and the pituitary gland. Different layer of Meninges present in the human brain and the synthesis and circulation of the Cerebrospinal fluid and its absorption. The brief knowledge about the pituitary gland. The hormones produced and stored by the pituitary gland.
2. Meninges
• The meninges are the three protective membrane that envelope the
brain and spinal cord , collectively forming the Central Nervous
System ( CNS) .
• They act as a shock absorber , cushion and barrier against harmful
substances , playing a vital role in the health and function of CNS .
3.
4. • Dura mater- The toughest and outermost layer , made of two fibrous
sheets. It anchors the CNS to the skull and spine , providing structural
support.
• Arachnoid mater – A delicate, web like layer separating the dura
from the pia mater. It houses a cavity filled with CSF , which cushions
the brain and spinal cord.
• Pia mater – The innermost layer , closely adhering to the brain’s
surface and following its contours . It nourishes the CNS by supplying
blood vessels and aiding in CSF circulation.
5. Space Location Content Significance
Epidural
Between skull/ spine and
dura mater
Fat., blood vessels,
connective tissue
Can expand with trauma or
infection leading to spinal
cord compression.
Subdural
Between dura and
arachnoid mater
Normally just a thin layer of
fluid
Can expand with bleeding
or inflammation causing
pressure on the brain
Subarachnoid
Between arachnoid and
pia mater
Cerebrospinal fluid
Crucial for cushioning,
nutrition, waste removal
and pressure regulation in
the CNS
6. Cerebrospinal fluid ( CSF)
• Cerebrospinal fluid is a clear colourless fluid found in the
brain and the spinal cord. It is an ultra filtrate of blood
plasma and is contained within the subarachnoid space and
the central canal of the spinal cord.
7. Synthesis of CSF
• CSF is produced by specialized tissue called choroid plexus.
Choroid plexus are located in the walls of the lateral
ventricles and in the roofs of the third and fourth ventricles.
A choroid plexus shows numerous villi , via which it secretes
the CSF
8. Circulation of CSF
• The CSF passes from the lateral ventricles to the third ventricle through the interventricular
foramen.
• From the third ventricle, the CSF flows through the cerebral aqueduct to the fourth ventricle.
• From the fourth ventricle, some CSF flows through a narrow passage called the obex and enters
the central canal of the spinal cord. However, the majority of CSF passes through the apertures of
the fourth ventricle; the median aperture, two lateral apertures. Via these openings, the CSF
enters the cisterna magna and cerebellopontine cisterns, respectively.
• From there , the CSF flows through the subarachnoid space of the brain and spinal cord.
• It is finally reabsorbed into the dural venous sinuses through arachnoid granulations.
Lateral ventricles ---third ventricle ---fourth ventricle ---central canal of the spinal cord ---.
subarachnoid space .
9. Functions of CSF
• Cushioning : CSF acts like a shock absorber, protecting the brain and spinal cord
from bumps, jolts and changes in pressure.
• Nutrient delivery : CSF carries essential nutrients like glucose and electrolytes ,
to the brain and spinal cord. It’s like a delivery service ensuring these vital organs
have the fuel they need to function.
• Waste removal : CSF helps remove waste products like toxins and cellular debris ,
from the brain and spinal cord. It’s like a garbage truck , taking out the trash to
keep things clean and healthy.
• Pressure regulation : CSF helps maintain a constant pressure within the skull and
spinal cord. This is crucial for preventing brain tissue damage and ensuring proper
blood flow . Think of it like a pressure valve, keeping things just right.
10. Pituitary gland
• Pituitary gland is a small , pea- sized gland located at the base of brain
below hypothalamus. It sits in its own little chamber under brain
known as the sella turcica. It’s a part of the endocrine system and is
in charge of making several essential hormones.
• Pituitary gland is divided into two main sections : the anterior
pituitary and posterior pituitary.
• Pituitary gland is connected to hypothalamus through a stalk of
blood vessels and nerves called the pituitary stalk ( infundibulum) .
11.
12. Anterior pituitary ( Adenohypophysis)
• This portion makes about 75% of the total mass of the pituitary gland . It is further
divided into three anatomical and functional regions :
• Pars Distolis ( anterior lobe ) : The largest and most prominent part of the anterior
pituitary . Produces and releases a number of important hormones :
• Growth hormone (GH) : Stimulates growth , cell regeneration and metabolic
functions.
• Thyroid Stimulating Hormone ( TSH) : Stimulates the thyroid gland to produce the
thyroid hormone.
• Adrenocorticotropic Hormone ( ACTH) : Stimulates adrenal gland to produce corticol
.
• Follicle Stimulating Hormone (FSH) : Regulates development of ovarian follicles in
female and sperm production in males .
13. • Luteinizing Hormone (LH) : Triggers ovulation in females and
stimulates testosterone production in males.
• Prolactin (PRL) : Stimulates milk production in mammary gland.
• Pars Intermedia ( Intermediate lobe) : A thin strip of tissue located
between the anterior and posterior lobes. It does not produce any
hormone.
• Pars Tuberalis : A narrow region that wraps around the infundibulum,
the stalk connecting the pituitary gland to the hypothalamus. It
produces a number of hormones, like gonadotropin releasing
hormone ( GnRH) which stimulates the release of FSH and LH from
the anterior pituitary .
14.
15. Posterior pituitary ( Neurohypophysis)
• This portion constitutes the remaining 25% of the total mass of the
pituitary gland. Unlike, the anterior pituitary, the posterior pituitary
does not produce its own hormones. Instead , it serves as a storage
and release site for hormone produced by the hypothalamus.
• Oxytocin : Stimulates uterine contractions during child birth and milk
ejection during breastfeeding.
• Vasopressin ( Antidiuretic hormone, ADH ) : Regulates water balance
by controlling the reabsortion of water in the kidneys thus helping to
maintain blood pressure and prevent excessive water loss.
16. Common disorders of pituitary gland
• Gigantism : Gigantism caused by excess GH production in children . The
symptoms of gigantism include excessive growth , delayed puberty and
headaches.
• Cushing’s disease : Cushing’s disease is caused by excess production of
ACTH hormone . The symptoms include weight gain , moon face and
buffalo hump.
• Prolactinoma : Prolactinoma is a tumor of anterior pituitary gland that
produces excess prolactin . Symptoms of prolactinoma include milk
production in women who are not breastfeeding , irregular periods and
headaches.
• Diabetes Insipidus : Diabetes Insipidus caused by deficiency of ADH . The
symptoms includes excessive thirst and urination.
