Neuroscience lecture 7

Protection: the meninges

1. dura mater - thickest, supplied by nerves

2. arachnoid mater - spider webby by connective tissue

3. pia mater - really thin layer delicate tissue

Epidural Hematoma

a collection of blood that forms between the skull and the dura mater

dura mater is injured 

middle meningeal artery ruptured 

filled with arterial blood

Subdural Hematoma

Dura mater is still attached 

layer between dura mater and arachnoid mater is filled with venous blood

Blood brain barrier (BBB)

Functions: 

protects against foreign invaders 

protects against hormones/ neuro transmitters in rest of body

maintains constant environment of brain 

babies in womb don’t have complete blood brain barrier which is why women while pregnant need to avoid drugs and alcohol 

Blood brain barrier (BBB) problems

1. hypertension

2. developmental problems with BBB

3. hyperosmolality 

4. microwaves

5. radiation 

6. infection 

7. trauma, ischemia, inflammation, pressure 

Circumventricular organs

1. pineal body

2. neurohypophysis (posterior pituitary)

3. area postrema

BBB is weak in these areas for receiving melatonin and other neurotransmitters more easily

Circle of Willis 

Case study 1: A patient comes in having right face and arm weakness. He is unable to speak for the most part and can only utter a few barely articulate words. He could follow many simple commands and answer yes/no question. Where do you think the damage is? What blood vessel is likely involved? Which of the lower 4 blood vessels are delivering blood to this area?

diagnoses: left side of brain effected specifically frontal lobe, Broca’s aphasia 

middle cerebral artery and left carotid artery problems  

Case study 2: . A patient is brought in by his wife. He was sitting at the kitchen table saying meaningless syllables over and over and wouldn't respond to any of her questions. His right arm was hanging down at his side. Where do you think the damage is? What blood vessel is likely involved? Which of the lower 4 blood vessels are delivering blood to this area?

diagnoses theory: left side effected, Wernicke's aphasia, middle cerebral artery and internal carotid problems

Cerebral cortex features

1. gyri

2. sulci

3. fissures 

• longitudinal 

• central 

• lateral 

layers of the cerebral cortex

• Layer III: large pyramidal cells 

• layer V: Betz cells 

Lobes of the brain: Frontal

executive function

• planning

• organization

• conscious thought

• some speech

• motor area

• etc.

Lobes of the brain: Parietal lobe

sensory area

body awareness

Lobes of the brain: Occipital lobe

vision

Lobes of the brain: temporal lobe

language

auditory

Lobes of the brain: Limbic lobe

houses the hippocampus

• memory

• emotion

Lobes of the brain: Insular cortex

pain

risk/ reward behavior

language dominance

most people are left hemisphere language dominant: 

• 96% of right handers 

• 85% of ambidextrous (use both hands equally)

• 73% of left handers 

as humans age the less they use their right hemisphere for language  

Interhemispheric connections

corpus callosum

white matter tracts 

(**fun fact: 200-250 million axons here)

corpus callosum problems

some people are born without a corpus callosum and can have similar characteristics to autism 

Cerebral vascular accident: Ischemic

blockage that stops blood flow

a. thrombotic:

b. Embolic:

c. transient:

Cerebral vascular accident: Hemorrhagic 

intracerebral hemorrhage / intra - axial (blood vessel inside brain bursts)

extra - axial: outside brain bleed

• subdural bleed

• subarachnoid bleed

1. aneurysms:  

2. AVMS (arteriovenous malformations)

Thrombotic:

walls of the vein is coated in stuff

Embolic:

when the coating on the walls of the vein breaks free and clogs a vein preventing blood from getting through 

transient: Ischemic attack

a temporary interruption of blood flow to the brain that causes neurological symptoms that typically resolve within 24 hours

• 1/3 of people who get this will end up with a hemorrhagic stroke

Aneurysms: 

ballooning of weakened blood vessel

AVMS (arteriovenous malformations)

cluster of abnormally formed vessels

main causes of strokes: 

1. high blood pressure

2. high cholesterol

3. smoking

4. obesity  

signs of a stroke (FAST)

F: facial drooping 

A: arms can’t be controlled

S: Speech slurred 

T: time to call 911!! 

Traumatic brain injury: closed brain injury

acceleration and deceleration head injury (common in car crashes) - both front and back of brain injured

impact based head injury

Traumatic brain injury: open head injury

when the skull is broken and brain is exposed 

example: bullet wounds in the head 

Traumatic brain injury: problems

• Coma • Drowsiness

• Headache

• Seizures

• Hydrocephalus

• Plegia/Paresis

• Dyskinesias

• Vision Changes

(they are told to rest and do light physical and mental activity)