4.3 Brain 1

Question 1

What is the blood supply from the heart to the brain?

Answer 1

heart  Aorta 
R. brachiocephalic to R. common carotid, L. common carotid arteries
R. L. internal carotid arteries
middle cerebral artery
anterior cerebral artery
anterior communicating artery

Question 2

What are the 3 ways the CNS is protected?

Answer 2

Bone and meninges
CSF
Blood brain barrier

Question 3

What happens if regular blood comes into contact with brain tissue?

Answer 3

Badness. Blood is toxic to the brain… as in hemorrhagic stroke

Question 4

What is the neuromuscular unit? How does it function?

Answer 4

blood vessels, surrounding glia, neurons
Capillary endothelial cells have specialized tight junctions, surrounded by astrocytes and modulated by nearby cells
protects the brain from blood-borne pathogens, certain hormones, toxins
lipid soluble, O2, CO2, alcohol, and water can cross
glucose, amino acids, ions transported in by highly selective membrane carriers
drugs resistance – compounds prevented from entering, actively removed

Question 5

What makes CSF? How much?

Answer 5

Made by choroid plexuses in ventricles, 125-150 mL 3x/day

Question 6

What is the function of CSF? Notable electrolytes?

Answer 6

Surrounds and cushions the spinal cord and brain
Absorbs shock if sudden jarring movements occur
exchange of materials and fluids between cells, neuroglia and interstitial fluid
watery, low K+, high Na+, very few proteins (vs. blood)

Question 7

Describe the circulation of CSF

Answer 7

arteries (blood in)
blood brain barrier
choroid plexus
lateral ventricles
3rd ventricle
cerebral aqueduct
4th ventricle
subarachnoid space
arachnoid villi
venous sinuses (back to blood)

Question 8

How do the dural sinuses drain the brain?

Answer 8

superior sagittal sinus
inferior sagittal sinus
straight sinus
transverse sinus
sigmoid sinus
internal jugular vein
brachiocephalic vein
superior vena cava  heart

Question 9

What can increase ICP?

Answer 9

with trauma, edema, hemorrhage, tumor, inflammation, ischemia, hypoxia, compression of the jugular vein (b/c no exit for blood)

Question 10

How to decrease ICP?

Answer 10

CSF drainage, lowering blood pressure, inducing vasoconstriction, lobectomy, craniectomy

Question 11

What are the major functions of the brain?

Answer 11

Homeostasis: regulation of internal environment
Emotion
Movement Control
Sensory Perception
Memory
Cognition (higher thought, awareness, judgement)

Question 12

What are the lobes of the cerebrum?

Answer 12

Frontal, temporal, parietal, occipital

Question 13

What are two significant white matter tracts in the cerebrum?

Answer 13

corpus callosum: connects right and left hemispheres, an example of a commissure
internal capsule: major projections to cerebral nuclei, an example of a projection tract

Question 14

What does a “primary” cortex do?

Answer 14

regions for motor and sensory integration are responsible for simple, direct and conscious processing of a single type of sensory stimulus or motor command
e.g.: Primary Motor Cortex: voluntary skeletal movement

Question 15

What are complex cortical association areas?

Answer 15

regions next to or near the primary cortictal areas that integrate multiple sensory stimuli, motor stimuli, and/or memory and emotional stimuli.
example: Visual Association Areas- processing of images, faces, “grandmother”

Question 16

What functional areas are in the occipital lobe?

Answer 16

Primary visual cortex – light, vision (“light”, shading)
receives sensory input from the retina (light receptors in eye)
Function: perception and processsing of light
Visual association area – complex processing of visual information (“cat” “grandma”)

Question 17

What functional areas are in the temporal lobe?

Answer 17

Primary auditory – sound, hearing
receives sensory input from the ear
Function: perception and processing of sound
Auditory association Area – interprets sound into context
Deep/inferior-medial region:
Limbic Association cortex: emotion processing
Hippocampus: memory and emotion
Primary Olfactory Cortex: processing of smell

Question 18

Where is the insula and what does it do?

Answer 18

Insula– lobe of cerebrum deep to the temporal lobe
Primary Gustatory Cortex – processing of taste
emotional areas – more research needs to be done

Question 19

What are the major functional areas of the frontal lobe?

Answer 19

Primary motor cortex
Function: voluntary control of skeletal muscles
contralateral control (neurons cross over before heading down spinal cord)
Supplementary Motor Area – movement sequences
Pre-motor cortex – learned, planned movement

Question 20

What are the major functional areas of the parietal lobe?

Answer 20

Primary somatosensory cortex – body sensations
Receives impulses involved in touch, pain, pressure, stretch from contralateral side of the body (axons cross in spinal cord before traveling up)
Function: processing and perception of body sensations, proprioceptive input from skin, joints, muscles
Somatosensory association: complex processing of body sensations stimuli
perception of complex patterns such as texture and shape of something you are holding

Question 21

In relation to the central sulcus, where are motor and sensory located?

Answer 21

Motor- pre central gyrus

Sensory- postcentral gyrus

Question 22

What is the homunculus?

Answer 22

The motor and somatosensory cortices in the pre and post-central gyri have somatotopic maps where regions of the body are mapped in different locations.
Visual representation of this map draws it like a “human” in the brain, called “homunculus”
Regions that are more sensitive, or have more input/output are over-represented on this internal brain map

Question 23

What are the major functional areas of the frontal lobe?

Answer 23

Prefrontal cortex – social and emotional planning and integration
involved with intellect, reasoning, judgment, concern for others, personality traits, and management of emotions
Develops later in life and is impacted by social environment
Linked to emotions, via The Limbic System

Question 24

When does the prefrontal lobe develop?

Answer 24

Develops later in life, impacted by social environment, tightly integrated with emotional system (limbic system)
=why teenagers are so stupid
In teens the circuits are still being defined

Question 25

What are the language areas of the brain? Where are they located?

Answer 25

surrounds lateral sulcus, majority of individuals have these areas in the LEFT hemisphere only = “Dominant” hemisphere
Broca’s area (Left frontal lobe) – motor and pre-motor association, controls muscles involved in speech production
Wernicke’s area (Left temporal lobe) – auditory and visual association area involved in speech processing, language comprehension

Question 26

What is the process for speaking a thought word?

Answer 26

1a. To speak about something seen, the brain transfers the visual information from the primary visual cortex to the angular gyrus of the parietal-temporal-occipital association cortex, which integrates inputs such as sight, sound, and touch.
1b. To speak about something heard, the brain transfers the auditory information from the primary auditory cortex to the angular gyrus. The information is transferred to
2. Wernicke’s area, where the choice and sequence of words to be spoken are formulated.
3. This language command is then transmitted to Broca’s area, which translates the message into a programmed sound pattern.
4. This sound program is conveyed to the precise areas of the primary motor cortex that activate the appropriate facial and tongue muscles for causing the desired words to be spoken.

Question 27

What are the basal nuclei?

Answer 27

Underneath white matter, is gray matter that is basal nuclei/ganglia
Integrative functions- within cerebrum, deep to cortex; help to adjust fine movements, work with the circuits of motor control, subconscious, very important for the adjustment of movement
2 parts- on either side

Triangle shape- lentiform nucleus
Small shape near lateral ventrical- caudate

Question 28

What is the function of the cerebellum?

Answer 28

important for position sense in space, COORDINATION of movement

receives visual, somatic, proprioceptive input from brainstem and motor planning information from cerebrum
Function: subconscious control of motor coordination, fine-tuning to motor patterns, smooth, coordinated movements

Question 29

What does the thalamus do?

Answer 29

“Gatekeeper” of information
sensory relay station containing many nuclei that receive sensory information and project to the cerebrum
Function: filter, process, relay sensory information to cortex regions, i.e. screens sensory impulses and decides if it should be passed onto the cortex and where it should be sent

Question 30

What is the hypothalamus? What does it do?

Answer 30

small region below the thalamus with vital autonomic and endocrine control

Question 31

What is the lambic system?

Answer 31

emotional response and processing
structures that form a ring around the thalamus
motivation, emotion, association memory

Question 32

What parts of the brain are associated with the lambic system?

Answer 32

Structures that form a ring around the thalamus:
cingulate gyrus
parahippocampal gyrus
hippocampus
mammillary bodies
amygdala
olfactory bulb, olfactory cortex
thalamic nuclei

Question 33

What are the 3 parts of the brainstem? General function?

Answer 33

3 regions that connect to/from the brain and spinal cord, multiple nuclei that regulate vital autonomic and cranial reflexes
Midbrain
Pons
Medulla

Question 34

What is the reticular formation?

Answer 34

interconnect regions of the brainstem that receive and integrate sensory input
Function: filter sensory input, attention, arousal of cerebral cortex, some control of sleep/wake states