Chapter 8, Chapter 7, Chapter 6, Chapter 5, Chapter 4, Chapter 3, Chapter 2, Chapter 1 pt. 2, Chapter 1 pt.1

What are sensory receptor organs specialized to detect?

Certain stimuli, converting them into electrical signals.

What is an adequate stimulus?

The type of stimulus to which a sensory organ is particularly adapted, such as photic energy for the eye.

What is sensory transduction?

The conversion of electrical energy from a stimulus into a change in membrane potential in a receptor cell.

What is the role of receptor cells?

They act as transducers, converting stimuli into electrical signals.

What is a Pacinian corpuscle?

A skin receptor that detects vibration and generates a graded electrical potential proportional to stimulus strength.

What are the six aspects of sensory processing?

Coding, adaptation, suppression, pathways, receptive fields, and attention.

How does coding in sensory processing work?

It involves patterns of action potentials that reflect a stimulus, encoded by features like number and frequency.

What is range fractionation in sensory processing?

Different cells have different thresholds for firing, allowing for a range of stimulus intensities.

How is stimulus location determined in the somatosensory system?

By the position of activated receptors, represented by labeled lines conveying spatial information.

What is adaptation in sensory processing?

The progressive loss of response to a maintained stimulus, with tonic receptors showing slow decline and phasic receptors displaying adaptation.

What is suppression in sensory processing?

The reduction of response to constant stimuli, influenced by accessory structures and top-down processing.

What distinguishes sensory pathways in the brain?

Each sensory system has a distinct pathway, often passing through the thalamus before reaching the cerebral cortex.

What is a receptive field?

The space in which a stimulus will alter a neuron's firing rate, differing in size, shape, and response to stimulation.

What is the primary somatosensory cortex (S1)?

The area that receives touch information from the opposite side of the body.

What is the secondary somatosensory cortex (S2)?

It maps both sides of the body in registered overlay, receiving input from the primary sensory cortex.

How does attention affect sensory processing?

It involves selecting or focusing on specific stimuli for enhanced processing, with the posterior parietal lobe and cingulate cortex being key regions.

What is synesthesia?

A condition where a stimulus in one modality creates a sensation in another, such as perceiving colors when looking at letters.

What are the three layers of skin?

Epidermis (outermost), dermis (middle, contains nerve fibers), and hypodermis (innermost, anchors muscles).

What are the four types of tactile receptors in the skin?

Pacinian corpuscles (vibration, fast-adapting), Meissner's corpuscles (touch, fast-adapting), Merkel's discs (touch, slow-adapting), and Ruffini's endings (stretch, slow-adapting).

How do large axons affect action potential conduction?

They conduct action potentials faster than small axons, with myelination speeding up conduction.

What is the dorsal column system?

The pathway that delivers touch information to the brain, synapsing in the medulla and thalamus before reaching the primary somatosensory cortex.

What is a dermatome?

A region of skin innervated by a particular spinal nerve.

How do dermatomes reflect human evolution?

The pattern of dermatomes reflects our evolution from quadrupedal (four-legged) ancestors.

What happens to cortical maps when a body region is removed?

The cortical area devoted to that body region shrinks, and areas for adjacent regions expand.

What is pain?

An unpleasant experience associated with tissue damage.

What is congenital insensitivity to pain?

An inherited syndrome where the person does not experience pain.

What are the three aspects of pain described by the McGill Pain Questionnaire?

Sensory-discriminative quality, motivational-affective quality, and cognitive evaluative quality.

What are nociceptors?

Peripheral receptors that respond to painful stimuli.

What is capsaicin?

The chemical that makes chili peppers 'hot' and binds to the TRPV1 receptor.

What distinguishes the TRPM3 receptor from TRPV1?

TRPM3 detects higher temperatures, does not respond to capsaicin, and is found on Aδ fibers.

What is the role of the Nav1.7 sodium channel?

It produces action potentials to report pain to the brain and is encoded by the SCN9A gene.

What is the anterolateral (spinothalamic) system responsible for?

Transmitting sensations of pain and temperature.

What neurotransmitter is released by peripheral fibers in the dorsal horn?

Glutamate, along with substance P, a neuropeptide.

What is neuropathic pain?

Pain that may be due to inappropriate signaling of pain by neurons, such as phantom limb pain.

What triggers migraines?

A wave of hyperexitation followed by cortical spreading depression, potentially involving CGRP release.

How does social rejection relate to pain perception?

It activates the anterior cingulate cortex, correlating with the distress felt by the individual.

What is analgesia?

The absence or reduction in pain sensation.

How do opiates reduce pain?

By stimulating opioid receptors in the descending pain control system.

What is the role of the periaqueductal gray (PAG) in pain perception?

It is involved in pain perception and can produce potent analgesia when electrically stimulated.

What is the placebo effect in pain relief?

A phenomenon where an inert substance can relieve pain, suggesting it works by releasing endogenous opiates.

What factors can enhance the placebo effect?

Large pills, expensive treatments, and the presence of doctors in white coats.

What is the effect of acupuncture on pain?

It can provide relief from chronic pain, but its effects may be blocked by naloxone, indicating it may act through endogenous opiates.

How does stress affect pain perception?

Stress can activate analgesia systems, producing pain relief when coping strategies are overwhelmed.

Zygote

A fertilized egg.

Ectoderm

The outer layer of the embryo that forms the nervous system.

Neural groove

The groove that forms between ridges of the ectoderm.

Neural tube

The structure formed by the joining of the ridges of the neural groove, which will develop into the central nervous system.

Forebrain

One of the three subdivisions of the anterior neural tube.

Midbrain

One of the three subdivisions of the anterior neural tube.

Hindbrain

One of the three subdivisions of the anterior neural tube.

Cerebral ventricles

The interior of the neural tube that becomes the fluid-filled spaces in the brain.

Central canal

The interior of the neural tube that becomes the canal in the spinal cord.

Fetus

The term for an embryo after 10 weeks of development.

Genotype

All of the genetic information of an individual.

Phenotype

All of the physical characteristics of an individual.

Gene expression

When a cell transcribes a gene and starts making the protein it encodes.

Cell differentiation

The process by which cells become a particular type, such as a neuron, depending on what genes are expressed.

Adult neurogenesis

The creation of new neurons in the adult brain.

Intellectual disability

A variety of conditions that impede mental growth.

Hypoxia

A transient lack of oxygen at birth that can affect the brain.

Maternal undernutrition

When undernourished mothers have underweight children who may suffer from brain abnormalities.

Teratology

The study of pathological effects of early exposure to toxic substances.

Fetal alcohol syndrome (FAS)

A developmental disorder caused by maternal ingestion of alcohol, resulting in anatomical, physiological, and behavioral impairments.

Autism spectrum disorder (ASD)

Developmental disorder characterized by impaired social interactions and language and a narrow range of interests and activities.

Environmental conditions

Factors such as air pollution that may be increasing the incidence of ASD.

Phenylketonuria (PKU)

A disorder of protein metabolism caused by absence of an enzyme that metabolizes phenylalanine.

Stages of nervous system development

Divided into six distinct stages: Neurogenesis, Cell migration, Differentiation, Synaptogenesis, Neuronal cell death, Synapse rearrangement.

Neurogenesis

Production of nerve cells.

Ventricular zone

Area where nonneural cells divide by mitosis to form nerve cells.

Cell migration

Process where cells that form in the ventricular layer move away along the surface of radial glial cells.

Cell adhesion molecules (CAMs)

Molecules that guide migrating cells and growing axons.

Knockout organism

An organism where the gene of interest has been made dysfunctional, providing clues about the normal function of the gene.

Transgenic

An organism where a manipulated gene is introduced, allowing comparison of development with normal organisms.

Differentiation

Process where cells express genes to make the proteins needed to acquire their specific appearance and function.

Induction

Process where the notochord releases a protein that directs some cells to become motor neurons.

Stem cells

Undifferentiated cells that can divide, with daughter cells capable of assuming a new cell fate.

Regulation

Response to cell injury in development where other cells will develop and take its place.

Axons

Nerve fibers that grow and are guided by chemicals released by target cells.

Dendrites

Branch-like structures of neurons that receive signals from other neurons.

Synaptogenesis

The proliferation of synapses during the growth of brain cells.

Filopodia

Protrusions that emerge from growth cones at the tips of axons and dendrites.

CAMs

Cell adhesion molecules that filopodia adhere to during axon and dendrite growth.

Chemoattractants

Chemical signals that attract certain growth cones.

Chemorepellents

Chemical signals that repel growth cones.

Myelination

The process of surrounding axons with myelin, which allows for rapid communication in neuronal networks.

Apoptosis

Programmed cell death that is a normal part of development.

Caspases

Proteases that cut up proteins and DNA during apoptosis.

Diablo

A protein released by mitochondria that binds to inhibitors of apoptosis proteins (IAPs).

Neurotrophic factors

Chemicals that target cells produce, which neurons compete for; without enough, neurons die.

Nerve growth factor (NGF)

A neurotrophic factor produced by targets that keeps innervating neurons alive.

Brain-derived neurotrophic factor (BDNF)

A member of the neurotrophin family similar to NGF.

Synapse rearrangement

The process where synapses formed early in development are later retracted or reorganized.

Gray matter thinning

The net loss of synapses in late childhood/adolescence that causes a reduction in gray matter in the cortex.

Caudal-rostral direction

The direction in which thinning of gray matter continues, with the prefrontal cortex maturing last.

Cell death genes

Genes that are expressed only during apoptosis.

Bcl-2 proteins

Proteins that block apoptosis by preventing the release of Diablo.

Growth cones

Structures at the tips of growing axons and dendrites that respond to chemical signals.

Glia

Supportive cells in the nervous system that ensheath axons in myelin.

Intense phase of myelination

Occurs shortly after birth and extends into young adulthood.

Neurons

Cells in the nervous system that transmit information through electrical and chemical signals.