4.3 Brain 1 Flashcards
What is the blood supply from the heart to the brain?
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
What are the 3 ways the CNS is protected?
Bone and meninges
CSF
Blood brain barrier
What happens if regular blood comes into contact with brain tissue?
Badness. Blood is toxic to the brain… as in hemorrhagic stroke
What is the neuromuscular unit? How does it function?
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
What makes CSF? How much?
Made by choroid plexuses in ventricles, 125-150 mL 3x/day
What is the function of CSF? Notable electrolytes?
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)
Describe the circulation of CSF
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)
How do the dural sinuses drain the brain?
superior sagittal sinus inferior sagittal sinus straight sinus transverse sinus sigmoid sinus internal jugular vein brachiocephalic vein superior vena cava heart
What can increase ICP?
with trauma, edema, hemorrhage, tumor, inflammation, ischemia, hypoxia, compression of the jugular vein (b/c no exit for blood)
How to decrease ICP?
CSF drainage, lowering blood pressure, inducing vasoconstriction, lobectomy, craniectomy
What are the major functions of the brain?
Homeostasis: regulation of internal environment
Emotion
Movement Control
Sensory Perception
Memory
Cognition (higher thought, awareness, judgement)
What are the lobes of the cerebrum?
Frontal, temporal, parietal, occipital
What are two significant white matter tracts in the cerebrum?
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
What does a “primary” cortex do?
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
What are complex cortical association areas?
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”
What functional areas are in the occipital lobe?
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”)
What functional areas are in the temporal lobe?
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
Where is the insula and what does it do?
Insula– lobe of cerebrum deep to the temporal lobe
Primary Gustatory Cortex – processing of taste
emotional areas – more research needs to be done
What are the major functional areas of the frontal lobe?
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
What are the major functional areas of the parietal lobe?
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
In relation to the central sulcus, where are motor and sensory located?
Motor- pre central gyrus
Sensory- postcentral gyrus
What is the homunculus?
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
What are the major functional areas of the frontal lobe?
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
When does the prefrontal lobe develop?
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
