Chapter 1 Nerve cells and nerve impulses

Independence

Human life rarely achieves true independence.

Survival Activities

Few can perform all survival tasks alone.

Nervous System Cells

Composed of neurons and glia.

Neurons

Cells that receive and transmit information.

Glia

Supportive cells with various functions.

Blood-Brain Barrier

Protects and nourishes neurons.

Resting Potential

Electrical charge difference across neuron membrane.

Action Potential

Rapid change in neuron membrane potential.

Sodium-Potassium Pump

Maintains resting potential by ion exchange.

All-or-None Law

Action potential occurs fully or not at all.

Myelin Sheath

Insulates axons for faster signal transmission.

Saltatory Conduction

Jumping of action potentials between nodes.

Local Neurons

Neurons that communicate with nearby cells only.

Nourishment of Neurons

Essential for neuron survival and function.

Electron Micrograph

High magnification image of neurons.

Neuronal Interconnection

Neurons work together for complex functions.

Neuronal Count

Adult human brain has approximately 86 billion neurons.

Santiago Ramón y Cajal

Pioneered neuron staining techniques.

Microscopic Brain Views

Early techniques revealed limited brain details.

Neuronal Fibers

Long, thin structures connecting neuron bodies.

Neuronal Gap

Small gap between neuron fibers.

Chemical Basics

Understanding chemistry is essential for neuroscience.

Learning Objectives

Goals for understanding nervous system structure.

Module Structure

Divided into sections on neurons and impulses.

Neuronal Activity

Mental experiences arise from interconnected neuron activity.

Cellular Composition

Nervous system made of individual cells.

Neuroscience Study

Begins with examination of nervous system cells.

Interconnected Cells

Neurons rely on connections for function.

Survival Skills

Few possess skills for complete self-sufficiency.

Santiago Ramón y Cajal

Pioneer of neuroscience, studied neuron structure.

Neurons

Individual cells that transmit nerve impulses.

Cerebral Cortex

Region with approximately 16 billion neurons.

Cerebellum

Contains about 69 billion neurons.

Spinal Cord

Houses around 1 billion neurons.

Camillo Golgi

Developed silver staining technique for nerve cells.

Silver Salts

Used to stain nerve cells for visibility.

Nobel Prize 1906

Awarded to Cajal and Golgi for physiology.

Neuronal Gap

Small gap between neuron fibers and surfaces.

Microscopy

Technique revealing details of nervous system.

Nerve Cell Separation

Cajal's finding that neurons do not merge.

Infant Brains

Easier to study due to smaller cell size.

Plasma Membrane

Cell membrane separating internal and external environments.

Cajal's Drawings

Definitive illustrations of the nervous system.

Charles Sherrington

Co-founder of neuroscience, discussed in Chapter 2.

Cajal's Education

Faced challenges including imprisonment and public floggings.

Scientific Observation

Cajal emphasized importance of recognizing ordinary phenomena.

Neuronal Theory

Cajal opposed Golgi's theory of merging neurons.

Cajal's Philosophy

Believed in the complexity of neuronal influences.

Cajal's Legacy

Influenced modern neuroscience with his research.

Nervous System Cells

Composed of individual neurons, not a single unit.

Research Techniques

Cajal applied Golgi's methods to enhance neuron study.

Cajal's Background

Initially wanted to be an artist, studied medicine.

Cajal's Impact

His findings reshaped understanding of neuron structure.

Neuroscience Development

Late 1800s marked significant advancements in the field.

Individual Cell Theory

Concept that cells function independently in the nervous system.

Cajal's Solitary Experience

Imprisonment influenced his perspective on observation.

Nerve Cell Structure

Cajal's research revealed distinct neuronal architecture.

Cajal's Artistic Skills

Combined art and science in anatomical illustrations.

Nucleus

Membrane-enclosed region containing DNA.

Mitochondrion

Structure performing aerobic energy metabolism.

Ribosomes

Sites for synthesizing new protein molecules.

Endoplasmic Reticulum

Network transporting newly synthesized proteins.

Plasma Membrane

Controls material exchanges in and out of cells.

Dendrites

Branching fibers receiving information from neurons.

Axon

Long extension conducting impulses away from soma.

Soma

Cell body containing the nucleus of a neuron.

Presynaptic Terminals

End points of axons transmitting signals to other neurons.

Motor Neuron

Receives excitation and conducts impulses to muscles.

Sensory Neuron

Highly sensitive to specific types of stimulation.

Chromosomes

Structures containing genetic information in the nucleus.

Metabolic Activities

Processes providing energy for cellular functions.

Overactive Mitochondria

Burn fuel rapidly, causing overheating.

Underactive Mitochondria

Linked to depression and pain predisposition.

Mutated Mitochondrial Genes

Possible cause of autism according to research.

Chemical Channels

Protein channels allowing controlled flow of substances.

Nuclear Envelope

Membrane surrounding the nucleus, controlling access.

Neurons

Specialized cells transmitting nerve impulses.

Neuronal Shape

Varies significantly among different types of neurons.

Synaptic Receptors

Specialized sites on dendrites for receiving signals.

Fuzzy Spines

Small projections on dendrites enhancing signal reception.

Cellular Building Materials

Proteins providing structure and function to cells.

Chloride

An important chemical transported across membranes.

Calcium

Essential ion involved in various cellular processes.

Potassium

Ion critical for maintaining cellular membrane potential.

Sodium

Ion important for nerve impulse transmission.

Dendrite

Receives information; increases surface area.

Dendritic spines

Short outgrowths enhancing synaptic surface area.

Soma

Cell body containing nucleus and organelles.

Nucleus

Contains genetic material; controls cell functions.

Ribosomes

Sites of protein synthesis within the soma.

Mitochondria

Powerhouse of the cell; produces energy.

Axon

Thin fiber conveying impulses away from soma.

Axon length

Can exceed one meter in vertebrates.

Myelin sheath

Insulating layer around some axons.

Nodes of Ranvier

Gaps in myelin sheath for signal propagation.

Presynaptic terminal

Releases neurotransmitters to communicate with other cells.

Afferent axon

Brings information into a structure.

Efferent axon

Carries information away from a structure.

Interneuron

Neuron with dendrites and axon within one structure.

Intrinsic neuron

Neurons confined to a specific brain structure.