Designed by Pyeongsug Kim ©2010 Supplemental instruction Nervous system (Instro.) Picture from

Two types of cells in nervous tissue: Neurons and Supporting cells (glial cells in CNS) Peripheral nervous system (PNS) = cranial and spinal nerves (all nervous tissue outside the CNS) Nervous System Central nervous system (CNS) = brain and spinal cord Designed by Pyeongsug Kim, ©2010

Cranial nerve(PNS) Designed by Pyeongsug Kim, ©2010

A C D E H A:Dendrites B:Nucleus C: Axon hillcock D:Cell body E:Axon F (Pink) :Myelin H: Schwann cell G: Axon terminal __________ Nutritional center; nucleus and organelles. __________ transmit electrical impulses to the cell body. __________ nerve impulses originate there. __________ transmits impulse away from the cell body. __________ is wrapped around the axon B F (Pink) G D:Cell body A:Dendrites C: Axon hillcock E:Axon F(Pink):Myelin H:Schwann cell Designed by Pyeongsug Kim, ©2010

In periphery, myelin is produced by In CNS, it is produced by oligodendrocytes. Schwann cells. Schwann cells and oligodendrocytes are Supporting cells. Designed by Pyeongsug Kim, ©2010

How many type of cells are seen?Two:Neuron, Schwann cell What does myelin do? Advantage?Electrically insulates axon. ;improves the conduction speed of nerve impulses, enabling fast reactions What is the unmyelinated part A?Node of Ranvier A Myelinated axons conduct nervous impulses more rapidly than unmyelinated. Designed by Pyeongsug Kim, ©2010

Structural Classes of Neurons _______________ -One process -Dendrites act as receptors -Axon leads to brain or spinal cord -e.g. Most sensory neurons Pseudounipolar _______________ -Dendrites and axon arise from apposite ends of cell body. -e.g. Retina Bipolar _______________ -Dendrites and axon arise from apposite ends of cell body. -e.g. Motor neuron, Interneuron Multipolar Designed by Pyeongsug Kim, ©2010

Function of Nervous system 1) Senses _______ (such as sight, touch, taste, etc.) stimuli 2) Formulates a response to the stimuli : perceptions, thoughts, and reflexes  usually in the ______. CNS 3) Transmits signals rapidly between body parts :Sense organs  CNS :CNS  the muscles (Response) Designed by Pyeongsug Kim, ©2010

What are the two supporting cells (glial cells) in the PNS? What they do? ______________ -form myelin sheaths around peripheral axons ______________ -supply nutrients, some structural function. -act as protective, cushioning cells. -lining the exterior surface of neurons; -surround neuron cell bodies within ganglia * Ganglia = collection of cell bodies. Schwann cells Satellite cells Designed by Pyeongsug Kim, ©2010

What are the four supporting cells in the CNS? Astrocyte, Ependymal cells, Oligodendrocyte, & Microglia Designed by Pyeongsug Kim, ©2010

In the CNS A B E F G C Fluid! A: Capillary B: Astrocyte C: Ependymal cells D: Cerebral spinal fluid E: Neurons F: Oligodendrocyte G: Microglia What are B, C, F, and G? D Supporting(glial) cells Designed by Pyeongsug Kim, ©2010

A: Capillary B: Astrocyte C: Ependymal cells D: Cerebral spinal fluid E: Neurons F: Oligodendrocyte G: Microglia ______________are glial cell in CNSAll but not A & E ______________are common glial cell in CNS B: Astrocyte ______________form blood-brain barrier B: Astrocyte ______________Help with ion uptake and help move glucose from blood to brain. B: Astrocyte ______________Neural stem cells. C: Ependymal cells ______________Immune response in NS, recognizing infectious agents G: Microglia Designed by Pyeongsug Kim, ©2010

White matter (myelinated part) In CNS, Some have myelinated part. Other have unmyelinated part. Gray matter (unmyelinated part) (Cell bodies and dendrites are gray matter) Designed by Pyeongsug Kim, ©2010

________________ -Capillary specializations in the brain -Do not allowed most nutrients and other molecules in the blood to exit. - But, __________ help with ion uptake and help move glucose from blood to brain and form blood-brain barrier Blood-Brain Barrier astrocytes Designed by Pyeongsug Kim, ©2010

___________ located entirely within CNS, integrates functions in CNS Sensory (from sensory receptor to CNS) What are the two types of motor neuron? _________ stimulates skeletal muscles _________ affects smooth and cardiac muscle, also glandular secretion. Interneuron Somatic Autonomic Designed by Pyeongsug Kim, ©2010

___________ bundle of axons ___________ bundle of nerve cell bodies outside of CNS ___________ bundle of nerve cell bodies within CNS ___________ connects regions of CNS Nerve Ganglion Nucleus Tract Designed by Pyeongsug Kim, ©2010

There are three neuron types _____________________________________ Sensory neurons, Interneuron, & motor neuron Designed by Pyeongsug Kim, ©2010

Sensory neuronsMotor neurons -afferent neurons(to the CNS) -(PNS/CNS) neuron -to neurons in the CNS -stimulated by ___________. -efferent neurons (from the CNS) -(PNS/CNS) neuron -to muscles or glands -stimulated by ___________. Interneurons -association neurons -(PNS/CNS) neuron sense stimuli interneurons CNS Designed by Pyeongsug Kim, ©2010

________________ -Nerves that connect to the CNS in the spine -(PNS/CNS) ______ PNS -Bundle of axons in the PNS -Wrapped by _______________. -Most mixed nerves: ______________________. Nerve connective tissue sensory and motor neurons ________________ -Nerves that connect to the CNS in the head -(PNS/CNS) Cranial nerves Spinal nerves Designed by Pyeongsug Kim, ©2010

_________________ voltage across membrane due to only 1 ion where electrical and diffusion forces are equal and opposite. ie/ K+ =_______, Na+ = _____ Equilibrium potential -90mV60mV ________________________ -Not producing impulses, -Around _______ -K+ drives most of RMP because it is quite permeable. Resting membrane potential (RMP) -70mV Cell membrane is more pearmeable ( K+ than Na+ / Na+ than K+). Designed by Pyeongsug Kim, ©2010

Choose K +, Na +, Cl -, Mg 2+ ___ is very permeable and is high inside cell. The inside cell is large (negatively/positively) charged molecules inside the cell. ___ moves out faster than ___ moves in. K+K+ K+K+ N+N+ What is the protein transport on the membrane contributes to the resting membrane potential? Na+/K+ pump Designed by Pyeongsug Kim, ©2010

_______________ -The electrical nerve signal that travels through the axon. -” ALL or NONE!” Action potential Designed by Pyeongsug Kim, ©2010

Voltage-gated sodium channels are found all along the axon. Potassium channels are found near each voltage-gated sodium channel. Threshold voltage -The voltage enough to open the VG- channel -50 ~55mv Designed by Pyeongsug Kim, ©2010

1)Resting membrane 2) Membrane potential reaches at threshold. 3) Na+-VG channel open 4) Na+-VG channel close 5) K+-VG channel open 6) K+-VG channel close 7) Na+/K+ pump restore balance of the ions. Designed by Pyeongsug Kim, ©2010

Define “resting membrane potential.” How many mV is it? A potential difference across the membrane. -70mV *Choose Depolarization, Repolarization, & Hyperpolarization. ___________ back to the resting potential ___________ positive charges to flow into the cell. Repolarization Depolarization ___________ potential difference approaches zero ___________ potential difference increases by negative charges enter cell Hyperpolarization Depolarization Designed by Pyeongsug Kim, ©2010

*Choose depolarization, repolarization, & hyperpolarization, threshold, K+, Na+. The resting cell is more permeable to __ than __. The leakage channels for K+ are always (open/closed) at the resting cell. There are VG channels for K+ and Na+, which are always (open/closed) at resting cell. At ________ by ________, VG channels for __ are open and membrane becomes permeable to __, and __ can diffuse into cell causing _________.(positive feedback) ;causes a rapid change in MP from –70 to +30 mV *VG:Votage-gated K+Na+ threshold depolarization Na+ depolarization Designed by Pyeongsug Kim, ©2010

*Choose depolarization, repolarization, & hyperpolarization, threshold, K+, Na+. Just before VG channels for Na+, VG channels for__ are open and __ diffuses out of the cell causing __________, which repolarizes axon back to the resting membrane potential. *VG:Votage-gated How does the cell return back to the resting membrane potential? Na/K pumps restore balance of the ions. K+, repolarization Designed by Pyeongsug Kim, ©2010

The electrical nerve signal that travels through the axon. Action potential Action potention is formed by rapid depolarization of the membrane by (Na+/K+/Mg2+) (influx/efflux); followed by rapid repolarization by (Na+/K+/Mg2+) (influx/efflux). Designed by Pyeongsug Kim, ©2010

______________ When a region of the axon has started to depolarize, it must fully complete its entire depolarization sequence before a new action potential can begin  called the _______________. Refractory period refractory period Designed by Pyeongsug Kim, ©2010

Review for de-, re-,and Hyperpolarization Na+ K+ Na+ Resting membrane K+ Depolarization Hyperpolarization Hyperpolarization, but In action potential, repolarization Designed by Pyeongsug Kim, ©2010

Stronger stimuli stimulate more and more _______. As more action potentials are stimulated, their amplitude (increases/decreases/does not change). Strength effect = ____________ Increased stimulus intensity causes (more/less) APs to be fired. Action potential frequency Axons Designed by Pyeongsug Kim, ©2010

-interaction between a molecule (ligand) and a protein on or within a target cell (receptor). Ligand-Receptor interaction Ligands ~ Neurotransmitter, hormones…Receptors ~ Neurotransmitter receptors, hormone receptors, ligand-gated channel… (specific!) Designed by Pyeongsug Kim, ©2010

__________is a connection between a neuron, called __________, and an another cell, called __________. Synapse presynaptic postsynaptic Synaptic transmission at chemical synapses is via _______________. neurotransmitters There are a few _________ synapse in nervous system, in smooth muscle and in heart gap junctions. electrical Most are __________ synapses. chemical Designed by Pyeongsug Kim, ©2010

A : B : C: 1. Mitochondria Autoreceptor release NT by___________ 8. NT re-uptake pump Neuron (Presynaptic) Neuron or cells (Postsynaptic) Synaptic vesicle Synaptic cleft NT receptor Calcium Channel exocytosis C Neurotransmitter(NT) Chemical Synapse! Designed by Pyeongsug Kim, ©2010

Synaptic Transmission Action potentials reach at the axon terminal. VG-Ca2+ channels open. Ca2+ activates calmodulin. Calmodulin activates a protein kinase. Protein kinase promote fusion and exocytosis of vesicles. Designed by Pyeongsug Kim, ©2010

Depolarizing channels cause ___________________________ Hyperpolarizing channels cause __________ EPSPs (excitatory postsynaptic potentials) IPSPs (inhibitory postsynaptic potentials) Designed by Pyeongsug Kim, ©2010

EPSPs and IPSPs summate.  if membrane potential in postsynaptic cell reaches threshold at the axon hillock, a new AP is generated.  if not, no AP occur. Designed by Pyeongsug Kim, ©2010

Acetylcholine (ACh) is most widely used as ______ and has _________ and ___________ receptor.nicotinicmuscarinic NT ________________ nicotinic muscarinic Designed by Pyeongsug Kim, ©2010

Nicotinic ACh ReceptorMuscarinic ACh Receptor Where are they? Where do they do? Some glands Designed by Pyeongsug Kim, ©2010