PBL 1 Flashcards
what are the 2 functions of the meninges?
to provide a supportive framework for the cerebral and cranial vasculature
to act with the CSF to protect the CNS from mechanical damage
what are the 2 connective tissue layers of the dura matter?
endosteal layer (lines inner surface of bone of cranium) meningeal layer (lines endosteal layer)
where are the dorsal sinuses found?
between the endosteal and meningeal layers of the dura matter
what are venous sinuses responsible for?
Venous vasculature of the cranium, draining into the internal jugular veins.
what are arachnoid granulations?
structures filled with CSF that extend into the venous sinuses through openings in the dura mater and allow the drainage of CSF from subarachnoid space into venous system
what are the 3 layers of the meninges from superficial to deep?
dura mater, arachnoid mater, pia mater
what are the 2 groups of bones of the skull?
cranial bones and facial bones
what makes up the cranial bones?
frontal bone, parietal bone, temporal bone, occipital bone, sphenoid bone, ethmoid bone
in which bone is the foramen magnum found?
at the base of the occipital bone
what are the layers of the scalp?
skin, connective tissue, epicranial aponeurosis, loose areolar connective tissue and periosteum
where does the epicranial aponeurosis run from and to?
from the frontal muscle to the occipitalis
what is the function of the periosteum?
to provide nutrition to the bone and the capacity for repair
what are the 2 main arteries that supply blood to the brain?
internal carotid artery and vertebral arteries
what is the function of the circle of Willis?
to provide collateral blood flow between the anterior and posterior circulations of the brain, protecting against ischemia in the event of vessel disease or damage in one or more areas
describe the path of the internal carotid artery?
They originate at the bifurcation of the left and right common carotid arteries, at the level C4.
They move superiorly within the carotid sheath, and enter the brain via the carotid canal of the temporal bone.
Once in the cranial cavity, the internal carotids pass anteriorly through the cavernous sinus
what does the internal carotid artery give rise to?
ophthalmic artery posterior communicating artery middle cerebral artery anterior choroidal artery anterior cerebral artery
describe the cerebral venous drainage?
The cerebral veins empty into the dural venous sinuses situated within the subarachnoid space.
what do the superficial veins of the cerebrum drain into?
superior sagittal sinus
what do the deep veins of the cerebrum drain into?
transverse, straight and sigmoid sinuses
outline the pathology of subdural bleeds
usually a tear of cerebral veins occurs causing blood to escape from the blood vessel and form a blood clot/haematoma that puts pressure on the brain and damages it
what are the common causes of subdural bleeds?
RTCs, brain atrophy in elderly patients and alcoholics, assault
how do subdural bleeds present?
headache, feeling/being sick, confusion, personality changes, feeling drowsy, loss of consciousness
how are acute and chronic subdural bleeds different?
acute- symptoms start very soon after sever head injury
chronic- few days or weeks later symptoms begin to occur
what are the 2 most widely used surgical techniques for subdural bleeds?
craniotomy
burr holes
what is a craniotomy?
a section of the skull is temporarily removed so the surgeon can access and remove the haematoma
what is a burr hole?
a small hole is drilled into the skull and a tube is inserted through the hole to help drain the haematoma
where is the primary somatosensory cortex?
across the central sulcus and behind the primary motor cortex
what is the function of the primary somatosensory cortex?
Receives nerve impulses for touch, pressure, itch, tickle, temperature, pain, and proprioception, and is involved in the perception of these somatic sensations.
which Brodmann’s areas are the primary somatosensory cortex?
1,2 and 3
which brodmann’s area is the primary gustatory area?
43
what is the function of the primary gustatory area?
Receives impulses for taste and is involved in gustatory perception and taste discrimination
which brodmanns area is the olfactory cortex?
28
where is the olfactory cortex located?
in the uncus, found along the ventral surface of the temporal love
what is the function of the olfactory cortex?
Receives impulses for smell and is involved in olfactory perception
where is the visual area located?
on the calcimine sulcus deep within the inside folds of the occipital lobe
what brodmanns area is the visual area?
17
what is the function of the visual area?
Receives visual information and is involved in visual perception.
where is the primary auditory cortex located?
on the transverse gyrus that lie on the back of the superior temporal convolution of the temporal lobes
what brodmanns area is the primary auditory cortex?
41 and 42
what is the function of the primary auditory cortex?
Receives information for sound and is involved in auditory perception
what are the 3 areas of the motor cortex?
the primary motor cortex, premotor cortex and supplementary motor area
which brodmanns area is the primary motor cortex?
4
what is the function of the primary motor cortex?
the main contributor to the generation of neural impulses that control execution of movement
where is the premotor cortex located?
anterior to the primary motor cortex
what is the function of the premotor cortex?
responsible for some aspects of motor control
what are the functions of the supplementary motor areas?
internally generated planning of movement, planning of sequences of movement, and the coordination of the two sides of the body.
where is the supplementary motor area located?
on the midline surface of the hemisphere anterior to the primary motor cortex
what do association areas do?
integrate information from different receptors or sensory areas and relate the information to past experiences. Then the brain makes a decision and sends nerve impulses to the motor areas to generate responses
what is the prefrontal association complex?
A region of the brain located in the frontal lobe that is involved in planning actions and movement, as well as abstract thought.
what is the wernickes area?
The posterior section of the superior temporal gyrus in the dominant cerebral hemisphere, one of two parts of the cerebral cortex linked with speech
what is the brocas area?
A region in the frontal lobe of the dominant hemisphere (usually the left) of the hominid brain with functions linked to speech production
left untreated, what can raised inter cranial pressure cause?
brain injury, seizure, coma, stroke, or death.
why do we get raised intercranial pressure?
The cranium andthe relatively inelastic dura, form a rigid container, such that the increase in any of its contents (brain, blood, or CSF) will tend to increase the ICP.
what are common symptoms of raised inter cranial pressure?
headache, vomiting without nausea, ocular palsies, altered level of consciousness, back pain, and papilledema.
if the raised inter cranial pressure causes a displacement of brain tissue, what additional symptoms can you get?
pupillary dilatation, abducens palsies, and the Cushing’s triad
what is the cushings triad?
bradycardia , irregular respirations, and a widened pulse pressure.
