Lecture 3: The Brain Flashcards
Describe the dura mater
Strong, dense, fibrous membrane continuous with dura mater of the spinal cord
Has 2 layers: endosteal and meningeal layers
Endosteal= periosteum covering inner surface of calvaria. Does not extend through foramen magnum
Dural septae
The dura mater also gives way to another support and stabilisation consisting of the four cranial dural septa.
-Falx cerebri is the largest of the 4. It divides the brain into left and right hemispheres
-tentorium cerebelli- separates the occipital lobe and temporal lobe
-Falx cerebelli- divides cerebellum into r and l hemispheres
-diaphragma sellae
Falx, tent, falx
What is dural innervation?
Only meningeal layer that is innervated by sensory fibres
Richly innervated by meningeal sensory branches from trigeminal nerve, vagus nerve and upper cervical nerves.
They are stretch sensitive => headache
How is the dura mater innervated?
Branches of the trigeminal nerve
Describe the vasculature of the dura
Arteries of the dura supply more blood to the calvaria (ie bones of skull, ie parietal, temporal etc) than to the dura.
Middle meningeal artery (branch of maxillary)
Middle meningeal veins drain into pterygoid venous plexus
Dural blood supply
Internal carotid artery Maxillary artery Ascending pharyngeal artery Occipital artery Vertebral artery Middle meningeal arty Venous drainage => meningeal veins lateral to arteries
Dural venous sinuses
Where are they located?
Between periosteum and meningeal layers of dura. No valves.
-contains blood from superficial brain veins
Name some of the main dural venous sinuses
Slide 13
Study it bitch
What is the thing that connects both hemispheres together?
Corpus callosum
Describe the pia mater
Pa mat is extremely thin but highly vascularised. It sits very closely to gyri of brain and descends into sulci
What the fark is a leptomlenix?
= arachnoid mater + pia mater
Indicated by arachnoid trabeculae passing between arachnoid and pia layers.
Arachnoid is avascular and NOT attached to dura, it is held against dura by CSF pressure.
Label each ventricle of the brain
Slide ?
Hhhougviyfcut
Ventricles
What is a choroid plexus and what does it do?
What does CSF do?
Where is CSF produced?
Ventricles lined with ependymal cells forming the choroid plexuses that produces and secrete cerebrospinal fluid.
CSF removes waste products associated with neuronal activity and gives brain buoyancy to protect it from damage.
CSF is produced it him lateral, third and fourth ventricles
Arterial blood supply of brain
High energy use, no substrate (glucose) stored and can’t metabolise with ought oxygen. Need constant supply of oxygenated blood containing glucose.
Slide 26 be able to label it
What vessels exist Cerebral arterial circle
Anterior communication artery Anterior cerebral arteries Internal carotid arteries Posterior communicating arteries Posterior cerebral arteries Slide 27
Arteries of cerebrum
What are the principle arteries?
Anterior cerebral artery (branch of internal carotid artery)
Middle cerebral artery (branch of internal carotid) = largest branch, supplies most of the lateral surface of the cerebra hemispheres.
What is the cause/ effect of aschaemic stroke
Result of impaired cerebral blood flow
Rapid cell death
Brain doesn’t store glucose and is incapable of anaerobic metabolism
What is a chiasm?
An anatomical intersection or decussation
What is a decussation?
The action of crossing in the form of an X, especially a tract of nerve fibres crossing contra lateral (opposite) side of the CNS
What is a ganglion?
A mass of tissue containing cell bodies of neurons usually located outside of CNS and form an enlargement upon a nerve.
What is a commissure?
Connecting band of nerve tissue between two anatomical structures
What are fasciculus?
Bundles of nerve fibres that follow the same courses but do not necessarily have same functional connections
What is a tract?
Bundle of nerve fibres having a common origin, termination and function
What are the derivatives of the Forebrain (prosencephalon)
Telencephalon (cerebral cortex, white matter and basal ganglia)
Diencephalon (epithalamus (pineal gland), dorsal thalamus, subthalamus, hypothalamus)
What is the name for the elevated ridges, shallow groves, and deep groves. What is the covering that surrounds it all
Elevated ridges = gyri
Shallow grooves= sulci
Deep groves= fissures
All covered by meninges (pia mater)
What is the role or the hippocampus:
key role in memory and learning
What is the
Fornix
Corpus callosum
Septum pellucidum
Fornix= tract connecting hippocampus (part of limbic system, consolidates info from short term mem to long term) to mammillary bodies (pair of small round bodies under brain, which is part of diencephalon form part of the limbic system.)
Corpus callosum= commissure between cerebral hemispheres
Septum pellucidum stretches between the two to form medial wall of ventricles.
What are Amygdala
Non basal ganglia : grey matter nuclei
Located inferior to putamen and anterior to tail of the caudate nucleus
Emotional amplifier
Stimulation of amygdala= rage, fear, rest, relaxation. Dependent on prior mood
Label cortical areas
Slide ?
Neurulation
What does the neural tube become
What does the neural crest become
Brain and spinal cord
Neural crest becomes shwann cells that myelinate nerves of the PNS and peripheral ganglia.
Memorise table of slide 45
Do it
Know the function of different areas of the brain.
Slide 58
Ya
What is the function of the thalamus?
Sorts and edits all pre cortical input from all sensory systems except olfactory system. Then conveys information to the cerebral cortex
What is the function of the hypothalamus
Command centre for all autonomic functions in the body
Mammillary bodies activate sympathetic nervous system when stimulated
Function of the mammillary bodies
Receive input from hippocampal formation via fornix
-projects to anterior nucleus of thalamus
Function of pituitary gland
- connects to hypothalamus by the infundibulum
- anterior lobe –> hormone producing
- posterior lobe–> hormone releasing
- hypophyseal portal venous system carries hormones into circulation
Function or pineal gland
Lies between the superior colliculi on posterior wall of third ventricle.
- produces malatonin–> hormone that regulated circadian rhythms
- commonly calcified in middle age
What is the function of the lateral geniculate body
You wish to a geni for vision.
Relays visual impulses from optic tract to primary visual cortex
Function of medial geniculate body
Relays auditory impulses from inferior colliculus to primary auditory cortex
Be able to spot the ventricles in different angles inside the brain using app
Her diagrams are shit
Venous drainage.
Venous drainage by cerebral and cerebellar veins that drain to dural venous sinuses
