Exam 1 Flashcards
(42 cards)
Necrosis
Death of brain tissue
Brain Fun Facts
2% of body weight 3lbs or 1500 grams Consumes 20% of energy 80% of tissue, 10% CSF, 10% blood 1000mL of blood per minute
Breakdown of Nervous System
Nervous System (NS)
Peripheral NS
Autonomic NS
Sympathetic NS (fight or flight)
Parasympathetic NS (relaxation)
Somatic NS
Central NS
Brain
Forebrain
Midbrain
Hindbrain
Spinal CordIntegrated Theory
Alexander Luria, father of neuropsychology, doctorate of medicine education and psychology
“To understand the brain foundations for psychological activity, one must be prepared to study both the brain and the system of activity.”
Brain is comprised of functional systems, behavior interacts with three basic functions
- Brainstem
- Sensory Unit
- Motor Unit
Central fissure roughly separates sensory (below) and motor (above)
Pluripotentiality
Any area of brain can be involved in few or many behaviors
Functional systems had “plasticity” can be retrained
Neuropsychology
The study of human behavior following damage to or dysfunction of the central nervous system.
Study of brain/behavior relationships How do behaviors, emotions, and thoughts relate to the brain? What parts of the brain? How does the brain work? What capacities do humans have?
Why study brain/behavior relationships?
- Diagnostic Purposes
- Rehabilitation Purposes
- Intellectual Curiosity
How is brain/behavior studied?
Invasive procedures Ablation Radiation, kills brain cells Noninvasive procedures Brain Imaging Neuropsychological Testing
Search for Engram
Karl Lashley search for memory, rats in maze, memory isn’t in one locations, entire cerebral function
The brain is…
An electrical and chemical unit
Imaging Techniques
CT: blood pooling
FMRI: functioning (tumor)
PET: function with in brain (dementia)
Nervous System:
Two Kinds of Cell
Neurons (where the action is, start with 100 billion, end with 1 billion)
Glial (the forgotten majority)
90% in CNS
Repair, support, protect
Six Kinds of Glial Cells
- Oligodendrocytes
Extensions wrap around axon of some neurons in CNS
Wraps multiple spots on axon, don’t help with neuron repair - Schwann Cells
Extensions wrap around axon of some neurons in the PNS
Wraps on single spot on axon, helps with neuron repair (cut off finger) - Microglia: clean debris
- Astrocytes: part of blood brain barrier
- Ependymal Cells: line ventricles
- Satellite Cells: muscle repair
Multiple Sclerosis
In multiple sclerosis the myelin sheath, which is a protective membrane that wraps around the axon of a nerve cell is destroyed with inflammation and scarring, some repair early in disease progress. 40-60% depression, about 10% of population, suicide risk 3-15%, about less than 1%, balance/coordination muscle weakness
Neurons
A-B-E
Afferent neurons, sensory
Brain
Efferent neurons, motor
Interneurons: only found in the CNS, brain tissue, integrate and coordinate activity
Möbius Syndrome
Underdevelopment of 6th cranial nerve (eye) and 7th cranial nerve (lower jaw)- 12 cranial nerves don’t come out of spinal cord, directly out of brain
Difficulty mirroring behavior of others
No known cause:
Maybe genetic, but not clear pattern
Maybe loss of blood flow or oxygen
Emotions
Experience them, appear not to - no mimicry
Is the absence of mimicry advantageous?
About 30% have been diagnosed with autism spectrum
Two Gross Neural Structures in the Nervous System
- Clusters of cell bodies (cell bodies stay in spinal cord or brain)
- Bundles of axons
What is the longest nerve in your body?
Sciatic nerve - all the way to your toe
Anatomy of a Neuron
Image
224 miles per hour
Surface area increases with “fingers”
The Nerve Impulse
- It took time for the signal to get around
2. The signal was about the same strength
Ability to fire depends on membrane potential, which works through two principles…
- Diffusion: things in higher concentration move to a lesser (K+ out, NA+ in)
- Electrostatic Pressure: opposites attract (K+ stay in, NA+ go in)
Membrane Potential Info
Net flow: about 0.003% increase in NA+
Higher K+ in neuron (axon)
Higher NA+ outside neuron (axon)
Closer to zero, more likely to fire
Resting sodium and potassium channels closed
Protein channels control oxygen and carbon dioxide
All or nothing principle
Potassium runs out by diffusion and electrostatic pressure
All happens in the nodes of ranvier
Hyperpolarization
Farther from zero, less likely to fire, inhibit excitation/firing
Depolarization
Closer to zero and more likely to fire, only time you can’t fire again
