Neuroanatomy Flashcards
What are the three layers that make up the meninges?
- Dura Mater
- Arachnoid
- Pia Mater
2&3 - leptomeninges - thinner than dura mater
Falx Cerebri
Plough shaped fold of meningeal layer of dura.
Separates left & right cerebral hemispheres
Involved in planned motor movements & inhibition of unwanted movements when at rest
Basal Nuclei
Modifies motor activity generated by the precentral gyrus
Cerebellum
Directs sensory input to the correct area of cerebral cortex
Thalamus
Lies posteriorly on each cerebral hemisphere
Occipital lobe of cerebrum
Cortex on the base of the cerebral hemisphere responsible for interpreting smell/olfaction
Rhinencephalon
Commissural Fibres
Corpus Callosum
Contains cerebrospinal fluid (CSF)
Subarachnoid space
Lines the skull on the inside of the compact/cortical bone
Endosteal layer of dura mater
Lies directly on the surface of the sulci and gyri of the brain
Pia mater
Forms a web-like structure containing many blood vessels
Arachnoid mater
Forms the deep lining of the dural venous sinuses
Meningeal layer of the dura mater
Changes position during embryonic, fetal and postnatal development of the vertebral column
Conus Medullaris
Describe positions of central and lateral grooves
Central groove - between frontal & parietal lobes
Lateral groove - between temporal & above frontal & parietal lobes
Define & give example of Association Fibres; Commissural Fibres & Projection fibres
Association fibres - interconnect cortical sites within one hemisphere e.g. primary auditory cortex & secondary auditory cortex
Commissural fibres - run from one hemisphere to the other, connect functionally related structures e.g. corpus callosum - communication between left & right hemispheres
Projection fibres - pass between cerebral cortex & subcortical grey matter e.g. basal nuclei
Describe flow of CSF:
CSF produced by choroid plexus (lateral ventricles) –> 3rd ventricle –> aqueduct –> 4th ventricle –> subarachnoid space –> arachnoid villi of dural venous sinus - reabsorption of CSF
Accumulation of CSF in cranial cavity
Hydrocephalus
Protective role of arterial blood supply
Protects brain & spinal cord against any possible changes in blood supply, blood pressure etc.
Intracranial pressure increases:
blood pressure increases, volume of blood decreases - if pressure keeps rising the amount of blood supplied to the brain is insufficient
Non-communicating vs Communicating Hydrocephalus
Non-communicating hydrocephalus (obstructed) - flow of CSF is blocked along 1/more passages connecting ventricles
Communicating hydrocephalus - CSF can flow between ventricles which remain open
Blood brain barrier (BBB)
- Between arterial blood & brain (vascular endothelium of capillary bed in brain parenchyma)
- O2, CO2, glucose, alcohol, nicotine, heroine pass through cells
- Well developed barrier
- Non-fenestrated
- Tight junctions
- Thick basement membrane
- Astrocytes have foot processes wrap around capillaries - impermeable
- End plates become looser when we sleep - more permeable to flush out waste products
Blood- CSF barrier
- Choroid epithelium (choroid plexus)
- Tight junctions & impermeable
- Active transport of NA, Cl , bicarbonate ions
- well developed barrier
CSF - Brain barrier
- ependymal cells
- permeable
Structures that lie outside of the BBB
Hypothalamus - sensitive to hormones
Posterior pituitary - release of hormones
Pineal gland - release of hormones
Area Postrema (floor of 4th ventricle) - chemoreceptor trigger zone - the vomition centre
Lobes of Brain & functions
Frontal lobe - cognitive functioning, voluntary gross motor movement
Temporal lobe - memory processing & integration of memory with sensation, emotion, hearing & language
Parietal lobe - sensory information processing such as general sensation, taste, temperature, pain & pressure
Occipital lobe - visual processing
Anterior & Posterior parts of corpus callosum
Anterior - ROSTRUM (mouth & nose)
Posterior - SPLENIUM (back of head & neck)
