Lecture #19 - Support and protection of nervous system Flashcards
How many bones in skull?
28
Cranium = 8 (7 outside and 1 inside)
Face = 14 (7 inside and 7 outside)
Ear bones = 6
Vertebral column bones
26 7 (cer) 12 (tho) 5 (lum) 1 (sac) 1 (coc)
Name 8 bones of cranium
- Frontal
- Parietal
- Parietal
- Temporal
- Temporal
- Occipital
- Sphenoid - one bone comes out on either side
- Ethmoid (internal)
Name the three sutures in the cranium
- Coronal suture
- Frontal and parietal - Lambdoidal suture
- Occipital and parietal - Squamous suture
- temporal and parietal
Suture = the bones interdigitate
- Gaps between sutures when kid called
2. Allow what
- Fontanelles (membranous structures)
2. Allow brain to grow after birth - premature closure can block brain growth - cognitive impairment
Name the facial skeleton bones
Zygomatic x2
Maxillary x2
Nasal x2
Mandible x1
The 7 internal you don’t needa know
What’s the meninges?
Protective covering of the brian 1. Dura mater (2 layers) 2. Arachnoid 3. Pia mater Between skull and brain
Dura mater (3) (meninges #1) Tough mother
- Outermost layer of meninges
- Dense and fibrous - tough
- Two layers
- inner layer forms the DURAL REFLECTIONS
- space between layers forms VENOUS SINUSES
Dural reflections (2) and then 3 of them
- Inward extensions of dura mater (formed from inner layer of dura mater)
- Separate major divisions of brain (there are 3 of them)
Dural reflections:
- FALX CEREBRI (cerebrum)
- separates cerebral hemispheres
- median plane - FALX CEREBELLI (cerebellum)
- separates cerebellar hemispheres
- median plane - TENTORIUM CEREBELLI
-separates the cerebrum from the cerebellum
-horizontal plane
like a tent over cerebellum - piece of dura mater
Venous sinuses (2)
- Form between outer and inner layers of dura mater
- Venous drainage from the brain (drain the old CSF out of head into the jagular vein- apparently venous blood through these sinuses)
Arachnoid layer (meninges #2) (4)
- Layer beneath dura mater
- Contains blood vessels and CSF (in the subarachnoid space)
- Doesn’t extend into sulci (valleys)
- Has arachnoid granulations (villi)
Subarachnoid - between arachnoid and pia - filled with CSF
Arachnoid villi:
-perforate the dura
-transport old CSF from subarach into venus sinus
(CSF gets recycled after it goes through that space - the arch things do active transport and pushes CSF out and it goes into the jagular vein)
Pia mater (delicate mother) (meninges #3) (3)
- Transparent and delicate
- Blood vessels in arachnoid sit on top of this
- Adheres to brain and follows gyri and sulci
Meninges of spinal cord
- Have the three layers too
- The dura mater covers the dorsal and ventral roots - wrapping changes to epineurium at about when it comes out of vertebrae (becomes peripheral nerve)
The ventricular system (4)
- Space in brain bc brain aint solid; network of interconnected spaces within brain
- Filled with CSF which nourishes and protects the brain
- CSF is produced by the CHOROID PLEXUS which lies the ventricles
It has:
- Lateral ventricles
- Third ventricle
- Cerebral aqueduct
- Fourth ventricle
Circulation of CSF (4)
- Bathes and cushions the brain
- Generated by choroid plexus in ventricles
- Is sampled to determine of meningitis is present (inflammation of meninges)
Route: Lateral ventricle ---> Third ventricle ---> Cerebral aqueduct ---> Fourth ventricle ---> Subarachnoid space ---------> Enters the venous blood circulation via arachnoid villi/granulations (then jagular vein)
