Unit 4: Nervous System

Anatomy

• Function

  • Dendrite -

  • Cell body -

  • Axon -

  • Myelin sheath - speeds up transduction through h

  • Axon terminals -

• Order of propagation

  • Dendrite → axon → axon terminals

Action potential

• Two particles involved are sodium and potassium (both cat ions)

• Resting state - sodium moves out and -70mV

• Depolarization - sodium pumped in through sodium channels

• Repolarization - potassium is removed by opening potassium channels

• Hyperpolarization - refractory period is part of this

Synapse

• Action potential in presynaptic cell triggers calcium channels to open and calcium comes in

• Calcium binds to vesicles and exocytosis releases neurotransmitters

• Reuptake removes neurotransmitters from synapse

• Swan cells make myelin (protein that increases speed of propagation)

Parts of brain

• Frontal lobe - critical thinking

• Temporal lobe - auditory cortex

• Hindbrain (contains pons, medulla, cerabullum) - basic life functions like breathing, etc.

• Etc.

Muscle contraction

• Sarcoplasmic reticulum releases calcium

• Calcium binds to troponin which triggers tropomyosin to reveal the myosin binding site

• Myosin binds to actin (ATP allows it to move to pull thin filament)

• Actin and myosin are also known as cytoskeleton elements

Reflex arc

• Role of receptor - detects stimulus (on switch)

• Sensory neuron - transmits info detected by receptor (afferent)

• Interneuron - communicates between sensory and motor neurons; in spinal cord; where processing comes to play

• Motor neuron - sends signals from neurous system to response/action site (efferent)

Copilot summary:

1. Introduction to the Nervous System

   1. Overview: Understand the structure and function of the nervous system.

   2. Key Terms: Neurons, synapses, neurotransmitters, action potential, resting potential.

2. Neurons and Their Functions

   1. Structure of Neurons: Dendrites, cell body (soma), axon, axon terminals.

   2. Types of Neurons: Sensory neurons, motor neurons, interneurons.

   3. Neuron Communication: How neurons transmit signals through electrical and chemical means.

3. The Action Potential

   1. Resting Potential: The electrical charge difference across the neuron's membrane.

   2. Depolarization: The process of the neuron becoming more positive inside.

   3. Repolarization: The process of returning to the resting potential.

   4. Propagation: How the action potential travels along the axon.

4. Synaptic Transmission

   1. Synapse: The junction between two neurons.

   2. Neurotransmitters: Chemical messengers that transmit signals across the synapse.

   3. Receptors: Proteins on the postsynaptic cell that bind neurotransmitters.

   4. Excitatory and Inhibitory Signals: How different neurotransmitters affect the postsynaptic neuron.

5. The Central and Peripheral Nervous Systems

   1. Central Nervous System (CNS): Brain and spinal cord.

   2. Peripheral Nervous System (PNS): All other neural elements, including sensory and motor neurons.

   3. Divisions of the PNS: Somatic nervous system, autonomic nervous system (sympathetic and parasympathetic divisions).

6. Neuroplasticity

   1. Definition: The brain's ability to reorganize itself by forming new neural connections.

   2. Mechanisms: How learning and experience can change the structure and function of the brain.

7. Neurological Disorders

   1. Common Disorders: Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy.

   2. Symptoms and Causes: Understand the symptoms and underlying causes of these disorders.