Neuromuscular 1 week 1 (nervous tissue review)

What is the soma

Cell body

What is the dendrites

Branch like extensions of the neuron that receive impulses and carry them toward the cell body

What is the axon

Extension of the neuron that carries impulses away from the cell body and toward other neurons, muscles or glands

What is the perikaryon

cytoplasm of neuron

What does the soma contain

Abundant cytoplplasm and organelles

What are all parts of the neurons permeated by

Microtubules and Neurofilaments

What are microtubules for

Transport

What are neurofilaments for

Scaffolding

T/F: dendrites never divide

False! they divide repeatedly

What do most axons give off

Collateral branches

What type of branch synapse on target neurons

Terminal branches

What do synaptic terminals allow for

Site of communication between 2 neurons or between a neuron and an effector cell

What is the most common synapse and what does it do

Axodendritic where synapses are usually excitatory in their effect on target neurons

What are the 3 types of synapses

axodendritic, axosomatic, axoaxonic

What do axosomatic synapses do

Inhibit

What axoaxonic synapses do

Almost always inhibitory

What are most synapses chemical or electrical and what is it dependent on

Chemical depending on the release of a transmitter substance

What are most chemical synapses comprised of (3)

Presynaptic membrane, synaptic cleft, and postsynaptic membrane

What are scarce in mammalian nervous systems

Electrical synapses

What do electrical synapses contain and what does this allow

Gap junction between dendrites or somas making it so no transmitter is involved meaning NO SYNAPTIC DELAY!

What organelles are contained within the perikaryon

Mitochondria, ER, Golgi bodies, microtubules and microfilaments

What are mitochondria concerned with

Cellular respiration and energy dynamics

What are ER important for

Protein synthesis

What do Golgi bodies do

Packaging of proteins in vesicles

What do microtubules and filaments allow or

Transport of protein and vesicles along the axon and dendrites bi directionally to and form the cell body

What is anterograde transport for neurons

Fresh components are continuously synthesized in the soma and moved into the axon and dendrites by a process

How aare worn out materials returned to the soma for degradation of lysosomes

Retrograde transport

What is rapid anterograde transport

Transport of free elements such as synaptic vesicles, transmitter substances, mitochondria, lipid and protein molecules

What is slow anterograde transport

Transport skeletal elements and soluble proteins including some of those involved in transmitter release at nerve endings

Is retrograde transport rapid or slow

Rapid

What is retrograde transport involved in

target cell recognition (waste disposal as well)

What are used for anterograde and retrograde work in microtubules

ATPases (need energy)

What are not seen in transport mechanisms and what do they provide

Neurofilaments provide skeletal support and may determine atonal diameter

What is clinical relevance of neuronal transport

Tetanus (carried to spinal cord via retrograde transport)

What structure types are involved in sensory neurons

Pseudounipolar and bipolar

What structure types are involved in motor neurons (efferent)

Multipolar Golgi type 1

What structure types are involved in interneurons

Multipolar Golgi type 1 and 2

What type of neuron is completely contained within the CNS

Interneurons (internuncial)

What type of neuron is a 1st order somatosensory

Pseudo unipolar

What type of multipolar is considerably longer

Golgi type 1 multipolar

What are the neuroglia of the CNS

Astrocyte, microglia, and ependymal cells, oligodendrocyte

What are the neruglia of the PNS

Schwann and satellite cells

What do schwann cells do

Support and maintain fibers of nerve cells, assist in repair and regeneration for fibers and myelination of axons

What do satellite cell do

Form supportive capsules around nerve cell bodies (similar to Schwann just no0 myelination)

What is the myelin producer of the CNS

Oligodendrocytes

What participate in phagocytosis of the CNS

Microglia

What forms and circulate CSF in the CNS

Ependymal cells

What are the 3 main functions of myelin

Electrically insulates nerve fibers from eachother

Increases the speed of transmission

Axonal regeneration in the PNS

What is myelin composed of

lipids and proteins

What is neurilemma

Specialized membrane surrounding the most external portion of the plasma or cell membrane of Schwann cells

What is the difference between myelination of the PNS and CNS

PNS is exclusive to one internode creating Nodes of Ranvier while Oligodendrocytes in the CNS aren't exclusive to one internode

What are the Nodes of Ranvier

Space or gap found on a nerve cells process and is located between between the myelin sheaths formed by cells as Schwann cells

What is the demylinating disorders of the CNS and PNS

CNS: multiple sclerosis (Oligodendrocytes attacked)

PNS: Guillain Barre (Schwann attacked)

What is delayed/affected in MS

Motor control there are many things it can affect due to it affecting the CNS go look on slides if you wanna know tbh

What is Lhermitte's sign?

Consists of an electric sensation down the back and or legs with neck flexion (this could be an indicator but not automatically MS)

What happens with GB normally

Can paralyze all muscles including respiration and produce Autonomic nervous system instability (rapid onset)

Which can be effective with regeneration the CNS or PNS

PNS!!!!! Cmon now

Why can't the CNS regenerate its axons

Rapidly convert to scar tissue and Oligodendrocytes bear growth inhibiting proteins that prevent it

Regeneration involves the coordination activity among what (3)

Macrophages: remove debris

Schwann cells: form regeneration tube and secrete growth factors

Axons: recreate damaged part

To regenerate, neurons must: (4)

By myelinated

Have intact cell body

Have functional Schwann cells

Axonal sport growth rate is 1-4 mm/day

What are the 4 functions of the plasma membrane

Maintain high concentration of materials in the cell

Keep harmful material out

Control the movement of materials into and out of the cell

Let the cell sense its environment

What move through a plasma membrane easily

Hydrophobic molecules

What can't move throught the plasma membrane on their own

Ions, hydrophilic molecules larger than water and large molecules such as proteins

What are the 4 basic mechanisms of transport

Diffusion (simple and facilitated)

Osmosis

Active transport

Bulk transport

What is the difference between passive and active transport

Passive is from high to low concentration and requires NO energy

Active moves from low to high concentration and requires energy

What is osmosis

diffusion of water across a selectively permeable membrane from high to low concentration of water

What is simple diffusion

Movement from high to low concentration without aid of carrier protein

What is facilitated diffusion

Solutes are passively transported through channels membrane proteins or by binding to a carrier requiring 2 steps

What are the 2 steps of facilitated diffusion

1 molecule enters a blind channel

2. Conformation change occurs in proteins and the channel opens to the opposite side of the membrane

What do ions in aqueous solutions tend to move during diffusion

From higher to lower concentration

What types of charges attract eachother and what dont

Unlike charges attract eachother while like charges dont

T/F :In simple diffusion lipid soluble molecules move readily across the membrane

True! Rate depends on lipid solubility

How do water soluble molecules cross in simple diffusion

Cross via channels or pores (aquaporins)

What is the MAJOR factor contributing to membrane transport and what are the other 2

MAJOR: concentration gradient

Then permeability and electrical potential

What are characteristics of passive (non gated) channels

Open at all times permitting ions to move across the membrane freely

What are characteristics of a voltage gated channels

Contain voltage sensitive string of AA that cause the channel pore to open or close in response to changes in membrane voltage

What are characteristics of channel pumps

Energy driven ion exporters and or importers designed to maintain a steady state of ion concentration

What is vital to maintaining resting membrane potential

Sodium potassium exchange pump (sodium potassium ATPase)

What are characteristics of transmitter gated channels

Abound in postsynaptic membranes (some activated directly by transmitter molecules

What are transduction channels activated by

Peripheral sensory stimulation

Sensory nerve endings exhibit different ________ specifications in different locations

Stimulus

In ion channels permeability of axon membranes to ion is determined by what

Number of open channels

Are ion channels normally selectively permeable?

Yes permeable to specific ions (na channels, K channels, Ca channels Cl channels)

What is an example of an ion channels that is permeable to classes of ions

Non selective cation channel (Na+, K+, Ca2+)

What are ungated channels determined by

Size shape and distribution of charge

What are the two types of gated channels

ligand gated and voltage gated

What is an example of a Ligand gated channel

Nicotinic acetylcholine receptor (AChR)

What is active transport

Solutes are actively transported by a carrier protein regardless of the concentration gradient (against concentration gradient)

How many and of what direction do sodium ATPase move (active transport)

3Na out 2 pump K in against concentration gradient

What are the two types of bulk transport

Endocytosis and exocytosis

What are two types of active transport

primary and secondary

What is primary active transport

Direct use of ATP to carry out active transport. (Against conc gradient)

What are 3 types of primary active transport

Na+-K+ ATPase pump

Ca2+ ATPase pump

H+ ATPase pump

How much of the cells energy do NaK ATPase pumps use

1/3-2/3 of cells energy

Where are calcium ATPase located

Present on cell membrane and SR

What do plasma membrane calcium atpase do

Maintain low cytosolic calcium concentration for proper cell signaling

What do sarcoplasmic reticulum calcium ATPase (SERCA) do

Transfer calcium from cytosol to SR during muscle contraction using ATP hydrolysis

What is SERCA inhibited by

Tumor promoting agent thapsigargin

Where are are hydrogen ATPase pumps found

Found in parietal cells of gastric glands (HCI secretion) and intercalated cells of renal tubules

What is secondary active transport

Indirect use of energy, transport is driven by energy stored in concentration gradient of another molecule (Na+)