IA Q3 Review

CNS (Central Nervous System)

Consists of the brain and spinal cord

Function: Voluntary movement, homeostasis, processing I

Important for sweating, insulin shivering

Brain (CNS)

• Perception and processing of sensory stimuli

• Execution of voluntary motor responses (somatic)

• Regulation of homeostatic mechanisms

Spinal Cord (CNS)

• Pathway for sensory and motor information between body and brain

• Initiates reflexes and automatic responses

Peripheral Nervous System (PNS)

Consists of nerves all around the body

Function: Sends sensory info to the CNS to carry motor information to the body

Neuron Structure

Dendrites

Receives signals from other cells

Soma

maintains cellular health, produces proteins, generates energy, and integrates incoming signals from dendrites, deciding whether to transmit an action potential down the axon

Axon

to transmit electrical impulses, known as action potentials, away from the neuron's cell body (soma) to other neurons, muscles, or glands

Myelin Sheath

acts as a protective, insulating layer around nerve axons, enabling faster and more efficient propagation of electrical impulses (action potentials).

Axon Terminal

to convert electrical impulses (action potentials) arriving from the axon into chemical signals, releasing neurotransmitters into the synapse to communicate with target cells

Nucleus

acts as the control center, housing DNA within the soma (cell body) to regulate gene expression, protein synthesis, and cellular maintenance

Neurotransmitters

allow neurons to communicate throughout the body, spanning the gap (synapse) between nerve cells

Synapse

A synapse is the fundamental junction where neurons communicate, passing electro-chemical signals to other neurons, muscles, or glands. Its primary functions are to transmit information rapidly, modulate (excite or inhibit) signals, and enable plasticity

Acetylcholine

Action: Helps neurons communicate & memory

Effect on the Brain: Attention, Learning Memory Forming

Effect on the Body: Muscle cramps heart rate & digestion

Diseases that occur if its not working properly: Alzehmiers, Myestheria Graves

Substances that are Agonists or Antagonists: Nicotine (Agonist), Botox (Antagonist)

Dopamine

Action: Regulates pleasure, reward, behavior

Effect on the Brain: Mood, Motivation, Pleasure, learning, focus

Effect on body: Muscle movement & coordination

Diseases that occur when it’s not working properly: Parkinsons disease, Addiction

Substances that are agonists / antagonists: Cocaine & Meth (Agonists), Anti-psychotic(antagonists)

GABA

Action: calms / decreases brain activity

Effect on the Brain: Decreases neuron activity (firing)

Effect on body: Prevents seizures, stress responses

Diseases that occur when it’s not working properly: Anxiety

Substances that are agonists / antagonists: Xanax

Serotonin

Action: Regulates mood & emotional stability

Effect on the Brain: Manages mood & calmness

Effect on body: Helps digestion, sleep, pain perception

Diseases that occur when it’s not working properly: Depression, Anxiety

Substances that are agonists / antagonists: Prozac, Zoloft (Agonists), MDMA (antagonists)

Epi / Norepi

Action: Neurotransmitters involved in stress response, activates flight or fight response (prepare for danger / excitement)

Effect on the Brain: Increase focus, alertness, attention & reaction time

Effect on body: Faster heart rate, breathing & blood pressure, (increased)

Diseases that occur when it’s not working properly: Chronic anxiety, high blood pressure, PTSD (overactive neurotransmitters), depression, attention problems (underactive)

Substances that are agonists / antagonists: Beta Blocker (Antagonists), Caffeine (Agonists)

Neuron processing cycle

Detects (stimuli) → Interprets (info) → Responds

Stimulus → PNS (sensory info) → CNS (processing motor info) → Response signal

Regions of the Brain

Frontal lobe

Responsible for executive function, decision making, making personality & speech

Parietal Lobe

Integrates sensory information (pain, touch pressure, temperature)

Temporal lobe

Responsible for processing language / info related to hearing, forming memories emotions, etc.

Occipital Lobe

Processing visual information from eyes, recognizing, faces & and forming visual memories

Cerebellum

Responsible for voluntary movements, balance, and learning new motor skills

Brain stem

Controls functions like breathing and heart rate to facilitate life

Cerebrum

Controls functions like conscious thought, memory, interpreting sensory input

Motor cortex

Controls voluntary movement

Corpus callosum

halves, enabling the integration of sensory, cognitive, and motor information

Pituitary gland

Produces and releases hormones

thalamus

Sensory motor signals (sensory relay station) takes and sensory info and sends to correct brain

Hypothalamus

Regulates hormones (hunger, thirst body temperature).

Hippocampus

forming memories and learning

Amygdala

processing fear, threat detection, and survival instincts

Spinal cord

Transmit signals between brain in the body (voluntary/motor movement)

Interneuron

Processes signals that are sent (CNS) sends sensory info and determines responses

Action Potential

An electrical signal

Can be found in excitable cells (neurons / skeletal muscle cells)

Excitable cells → cells that generate electrical signal from stimulus

Sodium Potassium Pump

Term

• Requires ATP energy

• Helps maintain resting membrane potential

• Moves more sodium ions out than potassium ions in

Membrane potential

Difference of the electrical potential between the inside and the outside of the cell.

Resting Potential

The electrical potential difference across the plasma membrane when the cell is in a non-excited state. (-70 mv)

Depolarization (rising phase)

Is a cellular process where the membrane potential becomes less negative (more positive) due to the rapid influx of sodium ions (+30 mv)

• inside becomes positive

Repolarization (falling phase)

Potassium ions leave the neuron making the inside more negative

Hyperpolarization

The shift in a cells membrane potential to a more negative value that its resting state

Extra potassium ions leave, inside becomes more negative than resting.

STAMP

If an incoming signal is too weak to reach threshold, the axon will not depolarize and the signal will stop.

Threshold

-55mv; the minimum depolarization required for a neuron to send a signal. If threshold is not reached, a neuron will not activate to send a signal and will remain at rest. (action potential will not start)

How are signals transferred between neurons?

1. Action potential reaches the axon terminal

2. Calcium ions rush into the axon terminal

3. Vesicles released neurotransmitters into the synapse

4. Neurotransmitter travel across the synapse & bind to neuron ion channel receptors on the dendrites of the nest neuron

5. The activated channel receptor allows sodium to rush into the neuron, beginning the next action potential.

*Neurotransmitters are chemicals in the system that help recieve signals

STAMP

when too much dopamine is r