Brain Flashcards
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what is corpus callosum?
other tracts?
white matter tract that connects the cerebral hemispheres
Association tracts = between gyri of the same hemisphere
Commisural tracts/fibres = from one hemisphere to the corresponding region of the other
Projection fibres = from cerebrum to thalamus, brainstem etc
basal ganglia function?
found?
Regulate initiation and termination of body movements. Also thought to be involved with memory, planning and emotional response (via the limbic system)
found deep in brain except substantia nigra which is found in midbrain
internal capsule separates the globus pallidus and putamen from the caudate nucleus
The large ‘hole’ in the middle of the section is the lateral ventricles that are usually filled with cerebrospinal fluid
diencephalon
The diencephalon lies deep in the brain and is composed of 3 areas – the largest is the thalamus that is involved with a large number of functional pathways. The hypothalamus plays a role in autonomic regulation of the body and links the nervous system to the endocrine system via its communication with the pituitary gland. The epithalamus is also called the pineal gland
midbrain connects?
parts?
Connects pons and medulla to diencephalon
Superior colliculi = visual tracking, scanning
Inferior colliculi = auditory startle reflex
Substansia nigra = control sub-conscious muscle action
Red nuclei = co-ordinate muscle movement
midbrain
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nerves from midbrain?
origin of cranial nerves III and IV
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pons function?
nerves?
Pontine nuclei = co-ordination and maximising voluntary motor output. Also tracts such as pneumotaxic which help to control breathing.
origin of cranial nerves V, VI, VII, and vestibular part of VIII
medulla function?
nerves?
Contains the pyramids (motor tracts); cardiovascular centres (rate/force heartbeat and diameter of vessels); breathing centres; nuclei concerned with touch, pressure and vibration. The olives = proprioception (joint and muscle position)
origin of cranial nerves IX, X, XI, XII and cochlear part of VIII
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between lobes of cerebellum?
function?
connections?
Vermis between lobes
Controls sub-conscious aspects of skeletal muscle movements and co-ordinates complex sequences
Regulate posture and balance
Superior cerebellar peduncle = midbrain to cerebellum.
Middle cerebellar peduncle = pons to cerebellum.
Inferior cerebellar peduncle = medulla to cerebellum
has important communications with the hypothalamus. It sits under a small piece of dura covering the sella turcica
function pituitary gland?
releases growth hormone
releases follicle stimulating hormone (FSH) and lutenising hormone (LH) – reproductive cycle
blood supply brain?
pathway?
The blood supply to the brain is from the internal carotid arteries and the vertebral arteries = circle of Willis
The vertebral arteries ascend the neck through the foramina in the transverse processes of the cervical vertebra and join close to the foramen magnum to form the basilar artery.
The internal carotid is a terminal branch of the common carotid artery that passes into the carotid canal (one each side) and through the cavernous venous sinus
The colours of the vessels correspond to the areas they supply on the diagrams of the brains on this slide.
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dura function? other layers?
The dura lines the skull, protects the brain and forms the dural venous sinuses.
The arachnoid covers the surface of the brain and carries blood vessels.
The pia adheres to the surface of the brain – going into the sulci and around the gyri.
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falx cerebri? Sinus?
what covers cerebellum?
The dura is folded to create supporting structures around the brain. The falx cerebri lies between the cerebral hemispheres and carries the inferior sagittal dural venous sinus in its lower border (shown by the star)
tentorium cerebelli covers the cerebellum
blood supply to meninges?
Anterior meningeal artery from the ethmoid branches of the internal carotid supplies the dura of the anterior fossa.
Middle meningeal artery from the maxillary artery passes through the foramen spinosum to supply the dura with blood. It is the major vessel supplying the dura and if damaged will lead to an extra-dural hematoma (compresses brain).
Posterior meningeal artery from the occipital artery supplies the dura of the posterior fossa.
nerve supply dura?
trigeminal nerve mainly
but also C2, C3 (carried by hypoglossal + vagus)
dural venous sinuses function?
drain blood from the brain and channel it into the internal jugular vein
each sinus found between?
star?
possible danger?
Each sinus is formed either between the periosteum of the skull and the dura (eg, sigmoid sinus) or between two layers of dura (eg, inferior sagittal sinus)
There is an area called the confluence of the sinuses (star) which collects the blood and passes it to the transverse and sigmoid sinuses. From there the blood from the brain drains into the internal jugular veins
Communication between emissary veins of scalp and superior sagittal sinus, and between cavernous sinus and facial/inferior orbital veins are a possible route of infection into the meninges (bacterial meningitis).
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CSF made by?
ventricles?
ependymal cells
There is one ventricle inside each of the cerebral hemispheres = lateral ventricles
one between the 2 parts of the thalamus = 3rd ventricle
one related to the cerebellum and brainstem = 4th ventricle
CSF circulation?
CSF circulates through the ventricles and into the sub-arachnoid space
Constantly re-cycled through arachnoid villi (granulations) into the dural venous sinuses
ependymal cells found?
ependymal cells are clumped together as choroid plexus that hang inside the ventricles and create CSF
arachnoid granulations
where the superior sagittal dural venous sinus lies in a living individual
