Ch 49 -Nervous Systems

Grey matter

Consists mainly of neuron cell bodies, dendrites, unmyelinated axons, and glia.

White matter

Consists of bundled axons that have myelin sheaths, giving a whitish appearance.

Central Nervous System (CNS)

Comprises the brain and spinal cord, integrating information.

Peripheral Nervous System (PNS)

Transmits sensory and motor signals between the CNS and the rest of the body.

Afferent neurons

Carry sensory information to the CNS.

Efferent neurons

Transmit instructions from the CNS to muscles and glands.

Reflexes

Body’s automatic responses to certain stimuli, generated by the spinal cord.

Motor system

Component of the PNS that carries signals to skeletal muscles.

Autonomic nervous system

Regulates smooth and cardiac muscles, and is involuntary.

Sympathetic division

Stimulates arousal and energy generation, initiating the 'fight-or-flight' response.

Parasympathetic division

Promotes calming and self-maintenance functions, leading to 'rest and digest'.

Enteric division

Controls the organs of the digestive tract.

Dopamine

A neurotransmitter whose release is affected in Parkinson's disease.

Amygdala

Brain structure involved in emotional memory storage.

Corpus callosum

Fibers that connect the two hemispheres of the brain.

Frontal lobotomy

A surgical procedure to sever connections in the brain, historically used for severe behavioral disorders.

Glial cells

Supportive cells in the nervous system that include Schwann cells and oligodendrocytes.

Neural plasticity

The capacity of the nervous system to be remodeled in response to activity.

Short-term memory

Temporary memory storage primarily associated with the hippocampus.

Long-term memory

Memory storage that involves strengthening connections in the cerebral cortex.

Hindbrain

Controls involuntary activities and coordinates motor functions.

Forebrain

Processes sensory input and regulates complex activities like sleep and learning.

Midbrain

Coordinates routing of sensory input to the appropriate brain regions.

Cerebellum

Part of the hindbrain that helps coordinate motor skills and learning.

Thalamus

Main relay station for sensory and motor signals to the cerebrum.

Hypothalamus

Regulates homeostasis and basic survival behaviors.

Suprachiasmatic nucleus (SCN)

Acts as the pacemaker for circadian rhythms.

Frontal lobe

Involved in decision-making and executive functions.

Temporal lobe

Involved in auditory processing and memory.

Parietal lobe

Processes sensory information related to touch.

Occipital lobe

Responsible for visual processing.

Broca's area

Essential for generating speech and language.

Wernicke's area

Essential for understanding language.

Neurons

Basic functional units of the nervous system that transmit signals.

Synapses

The junctions where neurons communicate with each other.

Cell body

Part of a neuron that houses the nucleus and organelles.

Dendrites

Extensions of a neuron that receive signals from other neurons.

Myelin sheath

Insulating layer around axons that speeds up signal transmission.

Schwann cells

Glial cells that myelinate axons in the PNS.

Oligodendrocytes

Glial cells that myelinate axons in the CNS.

Cognitive functions

Higher-level mental processes including learning, reasoning, and memory.

Motor cortex

Area of the brain that controls voluntary movements.

Somatosensory cortex

Processes sensory input from the body.

Parkinson’s disease

Progressive motor disorder characterized by muscle tremors and rigidity.

Alzheimer’s disease

Progressive brain disorder leading to memory loss and cognitive decline.

Neurotransmitter

Chemicals that transmit signals across synapses in the nervous system.

Flexed posture

Characteristic posture seen in patients with Parkinson’s disease.

Muscle tremors

Involuntary shaking movements often seen in Parkinson’s disease.

Blood-brain barrier

Protective barrier that limits substance movement between blood and brain.

Cognitive connections

Links that form between neurons to support memory and learning.

Embryonic development

The process during which more neurons and synapses are formed than will exist in adulthood.

Executive functions

Higher-level cognitive processes involved in decision making and behavior control.

Higher cognition

Advanced mental processes found in some animals, including problem-solving and abstract thinking.

Convoluted neocortex

Highly folded outer layer of the brain associated with complex cognitive functions.

Action Potential (AP)

A rapid rise and fall in voltage or membrane potential across a cellular membrane.

Saltatory Conduction

The process by which action potentials jump from one node of Ranvier to another along a myelinated axon.

Myelin Sheath

An insulating layer surrounding axons that increases the speed of action potentials.

Synaptic Transmission

The process through which neurotransmitters are released by a neuron and bind to receptors on a postsynaptic neuron.

Voltage-Gated Sodium Channels (NaV)

Membrane proteins that open in response to depolarization, allowing Na+ ions to flow into the cell.

Refractory Period

The time following an action potential during which a new action potential cannot be initiated.

Neurotransmitter

Chemical substances that transmit signals across a synapse from one neuron to another.

Chemical Synapses

Synapses in which neurotransmitters are released to transmit signals between neurons.

Graded Potential

A shift in the membrane potential that can vary in size and is not an all-or-nothing response.

Excitatory Postsynaptic Potential (EPSP)

A postsynaptic potential that makes the neuron more likely to fire an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A postsynaptic potential that makes the neuron less likely to fire an action potential.

Astrocytes

A type of glial cell that helps support and maintain the blood-brain barrier.

Neuronal Morphology

The structure and form of neurons, including their extensions and connections.

Tetrodotoxin

A potent neurotoxin that blocks voltage-gated sodium channels, preventing action potentials.

Cerebrospinal Fluid (CSF)

The clear fluid found in the brain and spinal cord that cushions and nourishes the CNS.

Diencephalon

A region of the brain that contains structures such as the thalamus and hypothalamus.

Mechanoreceptors

Sensory receptors that respond to mechanical forces like touch and pressure.

Oligodendrocytes

Glial cells in the CNS that produce the myelin sheath.

Synaptic Cleft

The gap between the presynaptic and postsynaptic neurons where neurotransmitters are released.

Coronal Section

A vertical plane that divides the body into anterior and posterior parts.

Neural Circuit

A network of interconnected neurons that work together to process information.

Pseudopregnancy

A physiological state resembling pregnancy that can occur in certain animals.

Endorphins

Neuropeptides that act as natural painkillers and help reduce stress.

Ligand-Gated Ion Channels

Ion channels that open in response to the binding of a chemical messenger.

Cortical Representation

The mapping of sensory functions to specific areas of the cerebral cortex.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors.

Nociceptors

Sensory receptors that detect harmful stimuli and are responsible for the perception of pain.

Cerebrum

The largest part of the brain, responsible for higher brain functions.

Forebrain, Midbrain, Hindbrain

3 Embryonic Brain Regions

Telencephalon, Diencephalon

The 2 components of the Forebrain

Cerebrum (cerebral cortex, white matter, basal nuceli)

Telencephalon includes:

Diencephalon (hypothalamus, thalamus, epithalamus)

Diencephalon includes:

Mesencephalon

The 1 component of the midbrain

Pons, cerebellum

Metencephalon includes:

Midbrain

Mesencephalon includes:

Metencephalon, Myencephalon

2 components of the hindbrain

Medulla Oblongata

Myencephalon includes what:

Frontal, Parietal, Occipital, Temporal

The 4 regions of the Cerebrum (Forebrain)

Tegmentum; Tectum

Metecephalon floor and ceiling

Degeneration of Substantia Nigra

Leads to parkinsons disease

Periaquiductal gray

Rich in opioid receptors; gate pain signals

Red nucleus

Responsible for rhythmic movement & gait

PONS

Where can serotonin and norepinephrin be found in the brain?

Raphe nucleus

Major source of serotonin

Iocus coerulus

Major source of norepinephrin

Ocelli

Pair of eye spots in planarians