Unit 2.1 Notes

Vocabulary

  • Hormone: Signaling molecule from glands affecting cell activity.

  • Central Nervous System (CNS): Brain and spinal cord; transmits impulses and coordinates the nervous system.

  • Peripheral Nervous System (PNS): Nerves outside the CNS.

  • Cerebrum: Forebrain for memory, learning, and emotions.

  • Cerebellum: Brain part for muscle coordination and balance.

  • Brain Stem: Connects spinal cord to forebrain.

  • Clinical Researchers: Study medication safety and effectiveness.

  • Experimental Researchers: Conduct basic medical research.

  • Neurons: Signaling cells for electrical and chemical signals.

  • Glial Cells: Support and protect neurons.

  • Cell Body: Neuron's central part with the nucleus.

  • Axon: Nerve cell process conducting impulses away from the cell body.

  • Dendrites: Neuron branches conducting impulses toward the cell body.

  • Cell Membrane: Semipermeable membrane around cells.

  • Nucleus: Contains cell's DNA.

  • Schwann Cell: Produces myelin sheath in PNS neurons.

  • Axon Terminals: Endings of axons contacting other cells.

  • Myelin Sheath: Insulates axon, improving impulse speed.

  • Nodes of Ranvier: Gaps in myelin sheath.

  • Action Potential: Electrical impulse traveling along the axon.

  • Synapse: Transfers nervous impulses between neurons.

  • Neurotransmitters: Transmit nerve impulses across a synapse.

  • Homeostasis: Stable internal conditions.

  • Mechanism of Action: How drugs interact with cells.

  • Agonist: Initiates a physiological response.

  • Antagonist: Inhibits physiological action.

  • Inverse Agonist: Induces opposite response to an agonist.

  • Reuptake Inhibitor: Blocks neurotransmitter reabsorption.

  • Reflex: Automatic response to a stimulus.

  • Reaction: Thoughtful response to external stimuli.

Nervous and Endocrine Systems

These systems facilitate communication and regulation within the body.

  • Nervous system: Uses electrical signals.

  • Endocrine system: Uses hormones.

Internship training starts in the Neurobiology Lab, focusing on the nervous system.

Nervous System Subdivisions

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

  • Peripheral Nervous System (PNS): Nerves transmitting information to and from the control center.

CNS and PNS process information and generate responses.

Brain as Control Center

The brain controls movement, breathing, decision-making, and communication.

Brain Structures

  • Cerebrum: Divided into lobes.

  • Cerebellum.

  • Brain stem.

Investigating the Nervous System

Neurological exams identify disorders affecting the brain, spinal cord, and nerves due to surgery risks.

Neurons and Glial Cells

  • Neurons: For sensations, movements, thoughts, and feelings. Essential parts: cell body, axon, dendrites.

  • Glial cells: Support neurons and maintain their environment. Types: ependymal, oligodendrocytes, satellite, astrocytes, microglial, and Schwann cells.

Glial cell dysfunction can cause brain tumors and neurodegenerative diseases like multiple sclerosis.

Neuropharmacology

Studies drug actions on the nervous system, focusing on cell communication.

  • Chemical and electrical factors send signals.

  • The brain and spinal cord maintain homeostasis.

Action Potential

Nerve cells send electrical signals (action potentials).

  • The sodium-potassium pump restores resting potential.

Neurotransmitters

Chemical messengers include serotonin, dopamine, and adrenaline.

Substance use disorder affects the brain, leading to uncontrolled drug use.

Neuron Structure and Function

  • Neurons communicate at synapses. The human brain has ~100 billion neurons, each with ~10,000 synaptic contacts.

  • Cell Body (Soma): Contains the nucleus and receives impulses. Damage results in neuron death.

  • Dendrites: Receive neural impulses. Branching is influenced by the environment.

  • Axon: Transmits messages from the cell body. May have branches and vary in length. Damaged neurons may sprout new terminals.

  • Myelin Sheath: Insulates the axon for faster impulse conduction. Multiple Sclerosis (MS): myelin degeneration impairs nerve impulse transmission.

The Synapse

Region between neurons consisting of the axon terminal, synaptic cleft, and dendrite.

Chemical Messengers (Neurotransmitters)

  • Chemicals made in the soma and stored in synaptic vesicles.

  • Neurotransmitters are released into the synapse as electrical impulses travel from the soma to the axon and bind to receptor proteins in neighboring dendrites, triggering a nerve impulse.

  • Behavior results from millions of cells communicating via electrochemical processes.

Inactivation of Neurotransmitters

  • Diffusion: Neurotransmitter drifts away.

  • Enzyme Deactivation: Enzymes alter neurotransmitter structure.

  • Glial Cells: Astrocytes remove neurotransmitters.

  • Reuptake: Neurotransmitter is taken back into the axon terminal.

Better Known Neurotransmitters

  • Acetylcholine (Ach): Functions: Movement, learning, memory, REM sleep. Deficits linked to Alzheimer’s.

  • Dopamine (DA): Functions: Movement, learning, attention, emotion. Excess: Schizophrenia. Deficit: Parkinson’s.

  • Serotonin (5-HT): Functions: Mood, sleep, impulsivity, aggression, appetite. Deficits linked to depression and aggression.

  • Norepinephrine (NE): Functions: Eating, sleep, mood. Deficits linked to depression and low energy.

  • Gamma-Aminobutyric Acid (GABA): Functions: Inhibitory, regulates anxiety. Abnormalities linked to epilepsy.