Lecture 3 - Hydrpcephalus and Meningitis Flashcards
(23 cards)
What are meninges?
The membranes that surround the brain and spinal chord
What is Hydrocephalus?
Water brain - build up of cerebral spinal fluid
What are some of the roles of cerebrospinal fluid? (5)
- stable environment for neurones
- Buoyancy for brain (cushion and reduces weight by 60%)
- Supplies nutrients and vital peptides by bulk flow and diffusion
- Removes metabolites / neurotransmitters to blood
- Buffers changes in extracellular ions, e.g. PH and K+
Where is CSF produced?
the choloid plexus
Describe the choloid plexus
- They are composed of a tight epithelium responsible for cerebrospinal fluid secretion, which encloses a core containing permeable capillaries and cells of the lymphoid lineage.
- Localized in the ventricular system
- CSF produced in choloid plexus flows into fourth ventricle and then exits down through spinal chord or upwards towards the surface of the brain.
Give some other roles of the choloid plexus other than csf release
role in development, homeostasis and repair of the CNS
Synthesis of trophic and angiogenic factors, chemorepellants and carrier proteins.
(released through polarized transport systems and receptor-mediated transcytosis.
Pressure in ventricles is ______ than in venus blood.
Pressure in ventricles is higher than in venus blood.
What are the meninges?(overall explanation, not specific)
the three membranes that line the skull and verterbral canal and then enclose the brain and spinal chord
Describe the meninges
Dura mater: tough
Aravhnoid marter: cross striations which cross sub-arachnoid space allowing csf to flow
Pia marter: follows all contours of the brain, into grooves etc.
Draw and label a diagram of the meninges
(lec 3 slide 4)
In the adult brain what is the
a) total CSF
b) total ISF
c) secretion rate per day
total CSF = 140ml
total ISF = 280
Secretion rate = 600ml/d
What is the PH of the CSF vs Serum
what is the K+ mM in the CSF vs Serum
PH: CSF = 7.3 Serum = 7.4 K+ (mM): CSF: 3.3 Serum: 4.4
What are the 2 membranes of the choroid plexus epithelium?
Basolateral membrane Apical membrane (with villi)
What do tight junctions do?
- Hold cells together
- Barrier function which
a) maintains the polarity of cells, allowing specialised transport functions to work.
b) prevents the passage of molecules and ions through the space between plasma membranes of adjacent cells
What is the enzyme inside the choroid plexus epithelium responsible for removing CO2 and producing the biproduct bicarbonate.
carbonic anhydrase
In the lecture slides, what dye is injected into the blood vessels in order to show the existence of the blood brain barrier?
Peroxidase
What are the causes of hydrocephalus?
- Obstruction of CSF pathways
e. g. tumor, congenital malformations, haemorrhage - Impaired absorbtion
e. g. thrombosis (increased venous pressure) - Oversecretion
e. g. tumours of the choroid plexus
What are the symptoms of hydrocephalus in new borns vs older children?
New borns: Fontanelle bulges and head expands
Over age 5: Headache, vomiting, hesitant movement etc.
What are some treatments of Hydrocephalus?
- Removal of cause (eg tumour)
- Shunt
- Ventriculostamy (tiny hole)
What is Meningitis?
Inflammation of the meninges
What are 2 viruses that cause viral meningitis?
Enteroviruses
Mumps and Measles viruses
What are 3 bacteria that cause bacterial meningitis?
- Meningococcal meningitis
- Pneumococcal meningitis
- Haemophilus influenzae b
How does bacterial meningitis cause deafness?
Pneumococcal (e.g. streptococcus pneumoniae) damage to cochlea (due to secretion of pneumolysin)
