Neuroscience

Cells of the Nervous System

Definitions:

Glial Cells: Helps with scaffolding, helps to line up neurons + insulate + immune responses + transport nutrients/waste

Neurons: information processors

Psychotropic drugs: Treat psych symptoms by restoring neurotransmitter balance.

Agonist: Mimic a neurotransmitter and receptor site

Antagonist: Blocks neuro activity at the receptor site.

Reuptake inhibitors: Prevent the bits from being reabsorbed. 

Their anatomy:

Soma: Cell body

Semipermeable membrane: small no charge pass, large high charge stop

Axon: A lil squiggle that the soma uses to send electrical signals to the terminal buttons

Terminal Buttons: Thingies that have synaptic vesicles with neural transmitters, which send the electrical signals elsewhere.

Myelin Sheath: Glial cells that insulate the axon. Gaps in the MS are called Nodes of Ranvier. If not their friction can make many disease

Synaptic Cleft: Gap/transmission site between two neurons 

Receptors:

Resting potential: Membrane’s ability to be held in a state of readiness. Ions are on both sides of the wall, and ready to woosh to the other side.

Threshold of excitation: How many positive ions can come to the other side before action potential begins.

Action Potential: Positive spike in energy.

Neurotransmitter effects are localized.

A charge passes through the membrane. In order for this to happen the intra and extracellular liquids have to have different electrical charges. This difference in electrical charges is membrane potential. Since the membrane is semipermiable, some charges are concentrated more inside or outside the membrane. 

From resting potential, once the signal is received, it changes states abruptly. During action potential, the electrical signals move through the axon, and bunny hop the nodes of ranvier. Sodium ions diffuse the next section, which raises charge>threshold of excitation and attracts more sodium ions. 

Action Potential is all or nothing. Chargers are at full strength, so your body perceives everything equally.  Once this happens, excess neurotransmitters break off, get broken down, and are reabsorbed. This process is called reuptake.

Parts of the Nervous System

Definitons:

Central Nervous System: Brain + Spinal Cord

Peripheral Nervous System: Everything else

Parts of the PNS

Somatic nervous system: Voluntary and conscious action

Motor neurons: CNS to muscle (efferent or moving away fibers)

Sensory neurons: Muscles to CNS (afferent or moving towards)

Automatic nervous system: Involuntary stuff like heard beat

Sympathetic nervous system: Stress related activities

Fight/flight response: Heighten sensitivity to get out of danger. If in that state for long periods of time without a way to react tis bad for your health.

Parasympathetic nervous system: Day to day sillies

Homeostasis: Wanting balance

Brain and Spinal Cord

Definitions

Neuroplasticity: how the nervous system can change and adapt.

Gyri (gyrus): bumps

Sulci (sulcus): grooves - most prominent is longitudinal fissure

Left Hemisphere: Right side body, associations in memory, selective attention, positive emotions.

Right Hemisphere: Left side of body, pitch perception, arousal, and negative emotions

Corpus Callosum: A thick band of fibers that connect the two hemispheres

Cerebral cortex: consciousness, thought, emotion, reasoning, language, and memory

Frontal Lobe: motor control, emotion, and language.

Movement Cortex: Planning and doing movement

Prefrontal cortex: High-lvl cognitive function

Broca’s Area: Language production

 Parietal Lobe: Processing sensory info

Somatosensory Cortex: touch, temp, brain. Different areas of this cortex process different sensations from diff body parts.  More surface area you touch, more nerves you use.  

Temporal Lobe: Hearing memory, emotion, lil bit of language

Auditory cortex: Hearing stuff

Wernicke’s Area: speech comprehension

Occipital Lobe: Visual/sight processing. The spot you see it in vision is the spot ur lobe processes it in (organized retinotopically) 

Thalamus: Sensory relay, 5 senses but smell goes through here before going elsewhere

Limbic system: Emotions and memory

Hippocampus: learning + memory

Amygdala: Having emotions and connecting them to memories

Hypothalamus: Homeostatic processes (body temperature, appetite, BP, etc), connects the nervous and endocrine systems, regulation of sexual motivation and behavior.

Midbrain

Reticular formation: Sleeping/waking up regulation, arousal, alertness, motor activity. Starts in midbrain but the gray matter extending to all the brain stem, clusters found in midbrain

Substantia Nigra/Ventral tegmental area(VTA): Diff structures but both make dopamine, needed for movement, involved in mood, reward, addiction  

Hindbrain

Medulla: Auto processes+ auto nervous system (Ex. breathing BP, heart rate)

Pons: Connects hindbrain to rest of brain. Also regulates brain activity during sleep

Cerebellum: Receives muscles, tendons, joint messages. Uses ear structure to control balance, coordination, movement, motor skills. Involved in task performance memory

Spinal cord is like a bridge. Protection by vertebrae and cushions by cerebrospinal fluid. Does simple processes in sensory reaction like moving away from hot object

Two hemispheres of brain, left right. 

U wrote that they were dominant, better to think that they work together bc results inconsistent

All lobes + Thalamus are forebrain.

Types of brain imaging

Computerized tomography scan (CT): X-ray, involves radiation

Positron Emission Tomography(PET): Pics of active living brain. Subjects have to consume a mildly radioactive juice called a tracer. The tracer gets into the bloodstream and can be monitored. More active a brain part is the more blood it gets.

Magnetic Resonance Imaging (MRI): We chuck a human into a metal tube with a thic magnetic field. We switch field off, the hydrogen atoms that were moving before are giving off signals we can pick up

Functional Magnetic Resonance Imaging (fMRI): MRI but shows brain activity through oxygen and bloodflow tracking. Both are more detailed then PET scans

Electroencephalography (EEG): Electrodes are placed on the head and they receive signals which are then printed out.

Endocrine System

Definitons:

Hormones: Chemical substances located in a series of glands. They are widespread and slow in their effect.

Major Glands in the system

Pituitary Gland: below hypothalamus: It sends out messenger hormones the control the other glands in the system. Also growth hormone, endorphins (pain relief), and fluid regulation hormones.

Thyroid Gland: Neck. Regulate growth, metabolism, and appetite. 

Adrenal Glands: on top of kidneys. Stress response (ex. epinephrine/adrenaline, norepinephrine/noradrenaline)

Pancreas: Insulin

Gonads: Sexual hormones. Female - ovaries/estrogen/progesterone. Male-testes/androgens (testosterone)