Neuro Physiology

Glial Cells

Non-excitable cells that support and protect the CNS and PNS

-Functions → protect, nourish, guide developing neurons, aid neural synapses

CNS

Where are these types of glial cells located?

-Oligodendrocytes, astrocytes, ependymal cells, microglial cells, pericytes

PNS

What are these types of glial cells located?

-Satellite cells, Schwann cells

Neurons

Excitable cells that initiate and transmit electrical and chemical signals 

-Synthesize, package, and release neurotransmitters

-Produce and conduct action potentials along the axon 

CNS, metabolic, connective, capillaries, ionic, PNS, autonomic, astrocytes

Neuroglia of the CNS and PNS: Astrocytes and Satellite Cells

-Astrocytes

• Star-shaped cells that are the largest and most common ___ neuroglia

• Provides structural and ________ support in the nervous system

• _________ tissue support to neurons

• Forms end feet on ___________ in the BBB, role in molecule transport

• Regulates _______ concentration of the ECF

-Satellite cell

• Located in the ___

• Surround sensory and ________ neurons and function to similarly to __________

ventricles, choroid, CSF, immune, antigen-presenting, health, plaques, debris

Neuroglia of the CNS and PNS: Ependymal Cell and Microglia

-Ependymal Cell

• Line the ________ and central canal

• Form the ______ plexus

• Produce and circulate ___ for the brain and spinal cord

-Microglia

• Function as resident _______ cells in the CNS

• Exhibit both phagocytic and ______-________ functions

• Also plays a role in maintaining overall brain ______ → find ______ and damages neurons / synapses to remove ______ and promote tissue repair

contractile, endothelial, tight

Neuroglia of the CNS and PNS: Pericytes

-_________ cells

-Surround __________ cells

-Help form and maintain _____ junctions of the BBB

soma, away, impulses, multipolar

Neurons

-Make up functional units of the CNS and PNS 

-Components: 

• ____ → cell body

• Axon → carries action potentials _______ from the soma 

• Dendrites → receive _________ from other neurons 

-Classification → __________ (MC), bipolar, unipolar, or anaxonic 

insulating, quickly, Ranvier, salutatory, location, oligodendrocytes, many, Schwann

Neurons and Myelin

-Myelin → fatty, _________ membrane that allows action potentials to travel more ________ (10x faster) along neurons

-Current is focused by nodes of ________, creating _________ conduction

-Different structure depending on location within the nervous system

• CNS → _____________; ____ axons

• PNS → ________ cells; one axon

action potentials, axon, opening, sodium, unidirectionally, 70, 55

Neurons

-Communicate via generation of nerve impulses AKA _____ ___________

-Self-regenerative signals that propagate along the ____ to initiate some type of response

-Mediated by _________/closing of voltage-gated _________ channels

-Move ___________, one way only

-resting membrane potential is -__ mV, -__ mV is the all or nothing threshold

communication, synapse, activation, hormones, electrical, gap, directly, chemical, neurotransmitters, common

Neuronal Impulse Transmission

-Neurotransmission is the process by which ___________ occurs within the nervous system. It occurs at a _______, which is a space between the pre-synaptic neuron and post-synaptic target 

-Mediates many effects including __________ of muscle contraction and secretion of __________ from glands 

-2 mechanisms: 

• _________ synapses → utilizes ___ junction channels, pre-synaptic current flows ________ into post-synaptic neuron 

• ________ synapse → utilizes _____________, much more ______ than electrical synapses in mammalian nervous system 

depolarization, calcium, cleft, post-synaptic, neuron, muscle, junction

Chemical Synapse Impulse Transmission

-Transmission Process

• ____________ of pre-synaptic nerve terminal by _________ → release of neurotransmitters

• Neurotransmitters diffuse across the _____ → binding and activation of receptors on the _____-________ target

-CNS → presynaptic axon and another ________

-PNS → neuron and target _______/gland cell

• Often called a _________

signal, GABA, serotonin, modulatory

Neurotransmitters

-Molecules that carry a ________ from one nerve to another nerve or cell type

-Important NTs → glutamate, ____, acetylcholine, dopamine, norepinephrine, and ________

-Properties → excitatory, inhibitor, __________. Short or long-lasting time course

excitatory, dopamine, reward, motor, motivation, mood

Dopamine

-Monoamine

-_________ and inhibitory → receptor dependent

-Acts on ___________ receptors (D1-D5)

-Very important in the _______ system 

-Functions → regulates ______ control, reward and ____________ pathways, prolactin inhibition, and _____ regulation 

modulatory, adrenergic, attention, stress, hormonal, rate, glucose

Norepinephrine and Epinephrine

-Catecholamine; ______________

-Acts on _________ receptors (alpha and beta) → binds to both, but one usually has a higher affinity

-Functions

• Norepinephrine → _________, arousal, ______ response, autonomic regulation

• Epinephrine → mainly ___________, mediating fight-or-flight responses (heart ____, BP, _______ mobilization)

modulatory, 5HT, mood, appetite, GI

Serotonin

-Monoamine

-___________

-Acts on ___ receptors, which can be inhibited by a lot of different substances

-Functions → ______ regulation, sleep-wake cycle, ________, pain perception, __ motility

excitatory, nicotinic, acetylcholinesterase, somatic, sympathetic, PNS

Acetylcholine

-Amine

-________ and modulatory, acts on muscarinic and _________ receptors 

-Degraded by ______________ in the nerve terminal 

-Location/Roles → NT of ________ efferent neurons, utilized by ___________ preganglionic neurons (adrenal medulla and sweat glands)

-Major NT of the ___

ligand, neuromuscular, autonomic, excitatory

Cholinergic Receptors: Nicotinic Receptors

-_______ gated ion channels

-Locations → skeletal muscle at the ____________ junction, ________ ganglia (SNS and PNS)

-5 sub-types

-Always __________

g-coupled, CNS, parasympathetic, inhibitory, heart, excitatory

Cholinergic Receptors: Muscarinic Receptors

-_-_________ protein receptors

-Locations → ___ and _____________ effector organs

-Excitatory and ___________ (receptor dependent)

• M2 (_____) → inhibitory, hyperpolarize

• M3 (smooth muscle, glands) → __________, depolarize

inhibitory, GABA, abundant, excitability, sedation, anxiety

GABA

-Amino acid

-_________

-Acts on ____ receptors (A and B)

-Most _________ inhibitory NT in the brain 

-Functions → reduces neuronal _________, promotes ________, motor control, and ______ reduction 

-Brainstem required 

excitatory, CNS, ionotropic, glutamate, common, learning, most

Glutamate

-Amino acid

-Excitatory → most abundant _________ NT in the ___

-Acts on __________ (NMDA, AMPA, kainate) and metabotropic ___________ receptors

-Most _________ NT in the brain

-Functions → synaptic plasticity, memory, __________, excitatory signaling in ____ brain circuits

Glutamate

Learning, memory, primary excitatory NT in the CNSA

Acetylcholine

Muscle contraction (NMJ) / autonomic nervous system (CNS)

GABA

Main inhibitory NT in brain, reduces neuronal excitability/stress

Dopamine

Motor control, reward, motivation, mood

Norepinephrine

Arousal, attention, stress response

Epinephrine

Similar to norepi, effects in spinal cord, thalamus, hypothalamus

Serotonin

Mood, sleep, appetite, pain regulation, modulates other NTs action

Histamine

Wakefulness, arousal, attention, inflammatory response

afferent, stimuli, sensory, CNS, unipolar

Sensory Neurons

-_________; enable perception of _______ outside the CNS

-Transmit _______ information from receptors in the skin/eyes/ears to ___ for processing 

-Receptor → sensory neuron → CNS

-Typically _______ and often myelinated 

efferent, movement, motor, muscles, multipolar

Motor Neurons

-________; facilitate ____________/physiologic responses

-Transmit _____ commands from CNS to _________ or glands to elicit a response

-CNS → motor neuron → effector tissue

-Typically __________ and heavily myelinated

voluntary, skeletal, conscious, acetylcholine

Somatic Neurons

-Function under _________ control, typically innervates _________ muscle

-Enable __________ perception/movement

-Utilize _____________ at neuromuscular junction

involuntary, respiration, neurotransmitters, homeostasis

Visceral Neurons

-Control the ___________ or unconscious activity of glands 

-Regulates cardiac muscle and most smooth muscle (___________ and digestion)

-Various _____________ utilized (Ach, norepi) depending on pathway 

-Functions to maintain _______________

excitatory, norepinephrine, sweating, inhibits, close, responses, emergencies

Sympathetic Nervous System

-”Fight or flight”

-Generally _________ → the primary NT is _____________

• Increases heart rate and BP, bronchodilation, mydriasis, and stimulates ___________

• _______ digestion and urination

-Ganglia _____ to the CNS

-Controls body __________ during __________ and excitement

opposes, acetylcholine, decreases, increases, effector, homeostasis

Parasympathetic Nervous System

-Rest and digest

-________ sympathetic nervous system

• Primary NT is ___________

• __________ HR and BP, bronchoconstriction, and miosis

• __________ peristalsis and salivation, promotes digestion and urination

-Ganglia near ________ organs

-Maintains ______________