Lecture 3: Venous drainage and cerebrum Flashcards

1
Q

Drainage of the blood from the brain

A

within the brain to the heart …

  • = drain into

fine veins (brain) - pial (pia mater) venous plexuses - cerebral veins - dural venous sinuses - internal jugular vein - heart

also feeding into the dural venous sinuses are the veins from the scalp through the emissary veins

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2
Q

Venous sinuses

A

• between two layers of dura mater
• receive venous blood from brain and scalp
• receive CSF
e.g. superior sagittal sinus

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3
Q

two layers of the dura mater =

A

periosteal (closer to the scalp) and the meningeal layer

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4
Q

Draining the superior and deep structures

A
1 - superior sagittal sinus 
2-inferior sagittal sinus 
3 - Straight sinus 
4 - transverse sinus 
5 - sigmoid sinus
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5
Q

Superior sagittal sinus

A
  • lies along the superior margin of the falx cerebri
  • joins the transverse sinus (right)
  • Arachnoid villi drain the CSF into the superior sagittal sinus
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6
Q

Inferior sagittal sinus

A
  • lies along the inferior margin of the falx cerebri

- joins straight sinus

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7
Q

Straight sinus

A

within tentorium cerebelli - protected by this dural surface

Joins left transverse sinus

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8
Q

Transverse sinus

A

one on each side (left and right)
left is continuous with the straight sinus
right is continuous with superior sagittal sinus

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9
Q

confluens in the brain

A

confluence of sinuses is the connecting point of the superior sagittal sinus, straight sinus, and occipital sinus. It is found deep to the occipital protuberance of the skull.

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10
Q

Sigmoid sinus

A

S shaped
forward continuation of the transverse sinus
opens into the internal jugular vein

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11
Q

Cavernous sinus

A

one on each side - right and left
lateral to pituitary gland, linked with venous channels
drains into the superior petrosal sinus into the transverse sinus
drains into the inferior petrosal sinus into the internal jugular vein

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12
Q

Draining the inferior structures

A

cavernous sinus

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13
Q

Infection in emissary veins

A

Veins can contribute to the spread of infection

problem because infection of scalp can end up in meninges infected which is meningitis

• The facial skin around the nose and upper lip also drains (via the ophthalmic veins) to the cavernous venous sinus - meninges around here can also be affected

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14
Q

Functional areas of the cerebral cortex

A

motor areas
sensory areas
association areas

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15
Q

Motor areas

A

voluntary motor functions therefore innervating skeletal muscle

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16
Q

sensory areas

A

conscious awareness of sensation

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17
Q

association areas

A

integrating diverse information for purposeful action

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18
Q

conscious behaviour involves

A

the entire cortex

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19
Q

How to fin the central sulcus on model

A

1 - find sulcus running parallel to the cerebral tissue
2 - go to the point where it terminates and then jump over this gyrus
3 - central sulcus is now found

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20
Q

Superior frontal gyrus location

A

The superior frontal gyrus is the medial most gyrus of the frontal lobe’s superolateral surface, running from the frontal pole anteriorly, all the way to the precentral sulcus and precentral gyrus posteriorly.

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21
Q

Inferior frontal gyrus location

A

The inferior frontal gyrus makes up the lateral and inferior surface of the frontal lobe and is separated from the middle frontal gyrus above by the inferior frontal sulcus.

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22
Q

Middle frontal gyrus location

A

The middle frontal gyrus is part of the superolateral surface of the frontal lobe, located between the superior frontal sulcus and inferior frontal sulcus, which respectively separate it from the superior frontal gyrus and inferior frontal gyrus.

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23
Q

Frontal lobe gyri

A

superior frontal
middle frontal
inferior frontal

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24
Q

Frontal lobe sulci

A

superior frontal

inferior frontal

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25
Inferior frontal gyrus contains
Opercular - 'lips', sitting at the entry level of the lips of the lateral sulcus Triangular Orbital - eyes sits in orbit which is inferior to it Brocas area = opercular and triangular, important area for speech
26
Primary (somatic) motor cortex
somatic means that it goes to body wall precentral gyrus (receiving information from other motor areas) “Somatotopy” “little man” Motor Homunculus • Area of cortex related to specific region is proportional to the amount of motor control over that region. - lots of neurons at the face and fingers because a lot of fine control is required • Each pyramidal neuron projects its axon to spinal cord.
27
Primary (somatic) motor cortex controls ...
- controls skilled voluntary movements of skeletal muscles (supplying about 30% of axons to the corticospinal tract = pyramidal tract) - controls muscles in body area having the most precise motor control - the face (expression), tongue (speech) & hands (typing, writing, holding etc) - the motor innervation of the body is contralateral
28
Primary (somatic) motor cortex damage - occlusion of a branch of anterior cerebral artery
* contralateral hemiplegia | * greatest in the lower limb
29
Primary (somatic) motor cortex damage - occlusion of a branch of middle cerebral artery
• contralateral hemiplegia • severe in the upper limb and face
30
Premotor cortex
* Controls learned motor skills e.g. learning to play piano, learning to type * Coordinates the movement * Involved in planning the movement Supplying about 30% of pyramidal tract axons
31
Premotor cortex damage
blood supply lost causes inability to control learnt motor skills, coordinate movement and plan movement
32
Supplementary and cingulate motor areas
* Receive inputs from many other cortical areas and thalamus * Axons contribute to the corticospinal tract and are part of the integration system supplementary motor area is particularly involved in speech
33
Supplementary and cingulate motor areas damage
• Damage - loss of desired skilled movements and voluntary movements & speech
34
Prefrontal cortex connections
Has extensive connections with parietal, temporal and occipital lobes
35
Phineas Gage
He became extravagant and anti-social, a foul- mouth and a liar with bad manners, and could no longer hold a job or plan his future. "Gage was no longer Gage"
36
Prefrontal cortex function
* involved with intellect, complex learning abilities (cognition), recall and personality * matures slowly and is heavily dependent on positive and negative feedback from one’s social environment * closely linked to the emotional part of the brain (limbic system) and plays a role in intuitive judgment and mood
37
Prefrontal cortex damage
• damage to the prefrontal cortex results in mental and personality disorders
38
Parietal lobe features
``` post central gyrus superior parietal lobule intraparietal sulcus inferior parietal lobule supra marginal gyrus angular gyrus (sits at end of superior temporal sulcus) ```
39
Primary somatosensory cortex
involved in sensation | postcentral gyrus
40
Sensory homunculus
The area of the cortex dedicated to the sensations of various body parts is proportional to how sensitive that part of the body is
41
Function of primary somatosensory cortex
* Spatial discrimination (neurons can identify the body region being stimulated) * Receive sensory information from contralateral side - e.g. right side is resembling information from the left side of the body
42
Damage of primary somatosensory cortex - Occlusion of a branch of anterior cerebral artery
* contralateral sensory loss | * greatest in the lower limb
43
Damage of primary somatosensory cortex - occlusion of a branch of middle cerebral artery
• contralateral sensory loss • severe: upper limb and face
44
Superior parietal lobule =
somatosensory association cortex
45
somatosensory association cortex function
superior parietal lobule integrating different sensory inputs relayed via the primary somatosensory cortex to produce a comprehensive understanding • position of limbs • location of touch or pain • shape, weight & texture of an object
46
damage to the somatosensory association cortex
unable to recognize objects without looking at them
47
Occipital lobe features
Parieto-occipital sulcus calcarine sulcus Primary visual sulcus - the gyri forming the walls of the calcarine sulcus
48
Visual association area
• communicates with the primary visual cortex • interprets visual stimuli (identify the things we see) (* faces are recognized in temporal lobe) We do our “seeing” with cortical neurons in this area - retina first captures the information from the eyes and then it is processed into 'seeing' here
49
Temporal lobe features
``` superior temporal gyrus middle temporal gyrus inferior temporal gyrus superior temporal sulcus Inferior temporal sulcus ```
50
Ventral surface features of the temporal lobe
``` inferior temporal gyrus rhinal sulcus uncus parahippocampal gyrus collateral sulcus occipitotemporal sulcus ``` Deep structures on the ventral surface = hippocampus (learning and memory), amygdala (emotion)
51
Hippocampus function
learning and memory | deep in the brain
52
Amygdala function
(almond) emotion - particularly anger associated with uncus
53
Deep structures on ventral surface (between frontal and occupital lobes)
``` thalamus hippocampus fimbria (fimbria becomes the fornix) fornix (in midline) septum pellucidum (in the midline) ```
54
auditory association area is also called
wernickes area
55
Wernickes/auditory association area
* perception of sound stimulus * store memories of sounds * involved in the language process
56
Primary auditory cortex
is sensitive to pitch, rhythm & loudness (or softness) | transverse temporal gyri is its location
57
Insular lobe function
Possibly - emotion - homeostasis - cognition - perception, self-aware
58
Insular lobe location
The insular cortex is located deep within the lateral sulcus of the brain. it is not visible from the surface
59
Broca's area
Motor Speech Area • The opercular & triangular parts of inferior frontal gyrus • Generates motor program for larynx, tongue, cheeks & lips involved in speech production • Transmits that to primary motor cortex for action • Becomes active when preparing to speak • present in one hemisphere only (usually the left)
60
Damage to Broca's area
nonfluent aphasia - slow speech, difficulty in choosing words - entire vocabulary may be 2 to 3 words unable to speak fluently
61
Wernicke's area
- Sensory Language Area • The auditory association cortex (posterior part of the superior temporal gyrus) • Permits recognition of spoken & written language • Creates plan of speech (based on what we heard)
62
Damage to Wernicke's area
fluent aphasia - speech normal & excessive, but makes little sense - no understanding of the meanings of words nor able to repeat them
63
Frontal lobe functions include...
Frontal lobe contains voluntary motor functions | and areas for language, planning, mood/personality, social judgment and smell
64
Parietal lobe functions include...
Parietal lobe contains areas for sensory reception and integration of sensory information
65
Occipital lobe functions include...
Occipital lobe is visual center of brain
66
Temporal lobe functions include ...
Temporal lobe contains areas for hearing, smell, | learning, memory and emotional behavior
67
Insular lobe functions include ...
Insular lobe | Possibly linked to emotion, homeostasis, cognition, perception, self-awareness.