Final - Exam 1 and New Bio Content Flashcards by Liz Jarzembowski

Excitatory Synapses are a type of _ potential

graded

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The equilibrium potential in excitatory synapses is roughly _mV

0mV, more positive charge

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Excitatory Synapses are more permeable to _.

cations (Na+, K+, Ca++)
-Na and Ca channels are open and K channels are closed so they don’t leave cell.

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Examples of excitatory NTs:

ACh (skeletal)
Glutamate
Substance P
NE
Epi
Dopamine

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Inhibitory Synapses have a _ channel and are found on dendrites on the NT synapse.

Cl-

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Inhibitory Synapses cause equilibrium potential to become _ polarized, moving Vm _ to the threshold.

hyperpolarize, farther

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Inhibitory Synapses Vm is:

-90mV

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Examples of Inhibitory synapses involve:

GABA and Glycine

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Examples of Excitatory synapses involve:

nAChR and Glutamate

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Inhibitory PostSynaptic Potential (IPSP) _ excitability and makes AP _ likely

depresses, less

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Examples of inhibitory NTs:

GABA
Glycine
ACh (cardiac)
Serotonin
Enkephalins
Endorphins

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Cl- ion channels for inhibitory synapses are found on _ in the NT synapse

dendrites

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Demyelination of the neurons in the CNS/ Oligodendrocyte defect causes this pathology:

Multiple Sclerosis
-autoimmune; Lhermitte sign (tingling shooting down torso/arms)
-loss of axons
Tx- corticosteroids and immunotherapy, avoid stress

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Which autoimmune disease causes muscle weakness by antibodies damaging nAChr on the post-synapse (nicotinic ACh receptors)?

Myasthenia Gravis
-tx: Neostigmine + Prednisone + possibly plasmapheresis

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What is happening in Myasthenia gravis?

paralysis, no AP can be generated because IgG antibodies damage nicotinic ACh receptors on post synaptic membrane

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Myasthenic Crisis:
-s/s
-tx

S/S: severe muscle weakening(diaphragm) -> respiratory distress/ DIB

Tx: anticholinesterase drugs (Neostigmine-AChE inhibitor), corticosteroids, immunosuppressants, plasmapheresis

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Cholinergic Crisis:
-s/s
-tx

S/S: resembles myasthenic crisis (extreme diaphragm musc. weakness/DIB) BUT occurs 30-60 min after taking anticholinesterase drugs-neostigmine); too much ACh -> overactivation of muscles -> weakness

Tx: withhold anticholinesterase drugs until serum level falls, vent. support, prevent respiratory complication

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Tensilon Test:

Edrophonium (anticholinesterase inhibitor) helps determine which of the 2 types of Myasthenia Gravis crises are happening

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Demyelination of neurons in PNS/ Schwann cell defect causes this pathology:

Guillian-Barre

Tx: vent support, IVIg, corticosteroids, plasmapheresis

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Acute, ascending motor paralysis would be a symptom of _ - _ syndrome.

Gullian-Barre

-neuronal matter can be restored since occurring in PNS

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What is happening in LEMS?

muscle weakness and paralysis, no AP generated because antibodies damage voltage-gated ion channels in presynaptic nerve terminals

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Which autoimmune disease causes muscle weakness by antibodies attacking voltage gated Ca++ channels on the presynaptic motor nerve terminal -> weak end plate potentials -> no AP?

LEMS
-tx: Neostigmine to boost the ACh there is at NM junction + chemo/radiation if necessary

-unlike MG, do not benefit from plasmapheresis

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Which of the following statements is true about smooth muscle?
A. Actin and myosin generate force through the crossbridge cycle.
B. Smooth muscle has more troponin than skeletal muscle.
C. Smooth muscle has the fastest myosin ATPase activity compared to skeletal and cardiac muscle.
D. Smooth muscle receives neural input from the somatic nervous system.

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Smooth muscle is similar to skeletal muscle in which of the following ways?
A. The mode of entry of calcium into the cytoplasm of the muscle cell
B. Both possess actin and myosin and the mode of entry of calcium into the cytoplasm of the muscle cells
C. The type of calcium-binding molecules they possess
D. Both possess actin and myosin
E. All answers are correct
F. Neuronal regulation

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During skeletal muscle contraction, thick and thin filaments bind together forming __________. A. tropomyosin B. crossbridges C. myosin heads D. troponin complex

Thick and thin filaments overlap within the __________. A. Z line B. H zone C. A band D. I band

What terminates smooth muscle contraction? A. Removal of calcium from troponin B. Removal of calcium from tropomyosin C. Dephosphorylation of myosin by a phosphatase D. Dephosphorylation by a kinase

Molecules common to both skeletal and smooth muscle crossbridge cycling include __________. A. myosin light chain kinase, calmodulin, and actin B. calmodulin C. phosphatases D. myosin light chain kinase E. actin F. myosin light chain kinase and actin

When an action potential travels along the sarcolemma of a muscle cell __________. A. DHP receptors in the T-tubule undergo a conformational change and Ca2+ flows down its concentration gradient through the ryanodine receptors B. voltage sensitive Ca2+ channels in the sarcoplasmic reticulum open, DHP receptors in the T-tubule undergo a conformational change and Ca2+ flows down its concentration gradient through the ryanodine receptors C. voltage sensitive Ca2+ channels in the sarcoplasmic reticulum open D. Ca2+ flows down its concentration gradient through the ryanodine receptors E. Ca2+ pumps in the sarcoplasmic reticulum are activated F. DHP receptors in the T-tubule undergo a conformational change

After the myosin ATPase hydrolyzes ATP into ADP + Pi, __________. A. the two products stay attached to the myosin head B. the two products stay attached to the myosin head, the myosin head is cocked and binds to a different G-actin molecule, ready for the power stroke C. the myosin head is cocked and binds to a different G-actin molecule, ready for the power stroke D. the myosin head has nothing bound, ready for the power stroke

Drugs that stimulate the neuromuscular signaling include Anti-AChE drugs, a couple examples would be:

neostigmine, physostigmine

Drugs that inhibit the neuromuscular signaling:

Curariform drugs and botox

Drugs that stimulate the neuromuscular signaling include ACh-like drugs, a few examples would be:

nicotine, carbachol, methacholine

Drugs that stimulate neuromuscular signaling:

ACh-like drugs and Anti-AChE drugs

Each muscle fiber contains _ made of actin and myosin.

myofibrils

Which medication can block ACh channels by competing for binding sites, preventing APs?

Curare (D-tubocurarin)

Which medication can prevent the release of ACh from nerve terminals leading to insufficient stimulus for an AP on skeletal muscles?

Botox

True or false: APs are mostly found on ligand gated ion channels on dendrites

False found on VOLTAGE gated (not ligand) ion channels on NODES OF RANVIER on Axons (not dendrites)

True or false: Graded Potentials can give rise to APs

True ex) like lighting a string on fire that is next to a stick of dynamite -some parts can fizzle out and not reach dynamite -if more parts of string catch fire, more likely to grow and spread to dynamite

True or false: Graded potentials are most commonly found on voltage gated ion channels on nodes of Ranvier

False, found on LIGAND gated (not voltage gated) ion channels on DENDRITES (not axons)

Graded potentials are different than APs because:

-no refractory period -graded = bigger stimulus = bigger response -summate = mult. stimuli = summed response -varied response = diff. parts of membrane are influenced differently ( NOT ALL OR NOTHING)

Graded potentials are AKA

local potentials

When impulses jump along the nerve fiber, increasing velocity and conserving energy, this is called:

Saltatory conduction

True or False: APs occur in the myelin sheaths of neurons

False, APs occur only at Nodes of Ranvier in neuron due to high concentration of Na+ channels located there

On Axons, each Node of Ranvier contains _ -gated ion channels.

voltage

True or False: Oligodendrocytes make myelin for neurons in the PNS.

False, CNS, not PNS

True or false: Schwann Cells cover axons and insulate/ speed up AP conduction.

False, Schwann cells make MYELIN which does this

An AP's conduction velocity depends on the _ and amount of _.

diameter and amount of myelin

Stages of AP: 1st stage- Membrane is _ and Vm is _ to _.

polarized, -70 to -90mV

Stages of AP: 2nd stage- A stimulus comes and excites cell, Vm becomes more _ due to influx of _. Once the Vm reaches threshold at _, it causes depolarization or _stroke

-Vm becomes more positive due to influx of Na+ -Vm threshold is -55mV causing depolarization or UPSTROKE

Stages of AP: 3rd stage- Na+ channels close and _ channels open, which enter the cell making it more _, but then rapidly diffuse out to make cell more _. This repolarizes the cell membrane during the _stroke.

-K+ channels open to enter cell making it more positive briefly then leave rapidly to make cell negative again - Repolarization occurs on downstroke

Stages of AP: After repolarization, sometimes there is overshoot and cell is more negative. The _ pump helps reestablish the concentration gradients after AP has occurred.

Na/K ATPase pump

Order of highest to lowest Vm: School Always Needs Some P.E.

Skeletal Muscle Astrocytes Neurons Smooth Muscle Photoreceptors Erythrocytes

Skeletal Muscle Vm

-85 to -95mV

Smooth Muscle Vm

-50 to -60mV

Astrocytes Vm

-80 to -90mV

Neurons Vm

-60 to -70mV

Erythrocyte/ RBC Vm

-8 to -14mV *has a higher affinity to Na+ than K+

Photoreceptor Vm

-40 (dark) to -70 (light) mV

Na/K ATPase brings _ Na+ ions to ECF and _ K+ ions to the ICF. This helps create a _ charge inside the cell.

3 Na+ ions out for 2 K+ ions in -creates negative charge

Na/K ATPase pump moves K+ _ the cell and Na+ _ the cell.

K+ moves IN, Na+ moves OUT; More Na outside of cell, so it has to be pumped against diffusion gradient to leave More K in the cell, has to be pumped against diffusion gradient to come in

The Na/K ATPase pump requires energy because both Na and K are pumped _ their respective gradients.

against

There are 2 types of Ca++ pumps. One pumps Ca++ out of cell against gradient using ATP. How does the other pump function?

Pumps Ca++ INTO the ER, SR, or mitochondria

There are leak channels for which 2 ions? Which one more readily leaks through?

Na+ and K+, K+ leaks thru more easily

Which ions are found more in ECF?

-Na+ -Ca++ -Cl- -Glucose

Which ion is found more in ICF?

K+

p53 gene is AKA

tumor suppressor gene -has t factors -needs to be ACTIVATED

In cancer cells, telomerase activity is high and this can extend the _ phase of the DNA synthesis proces.

S phase

Telomerase functions by:

adding bases to telomeres to make sure DNA isn't shortened.

Telomeres function by:

telling cell to stop dividing at the end of DNA

True or false: histone deacetylation of a tumor suppressor gene will more likely cause cancer.

true

True or false: Histone acetylation of an oncogene will more likely cause cancer.

true

Name a few conditions that can be caused by increased free radicals in the body:

-Alzheimer's -Diabetes Mellitus -Rheumatoid Arthritis

Duchenne's Muscular Dystrophy is the most common X-linked recessive neuromuscular disease. If a mother possessed 2 of these recessive genes and had a son, what chance does he have of expressing it?

100% because he receives his X chromosome from her.

Which inherited disease is characterized by defective/ leaky ryanodine receptors?

Malignant Hyperthermia

True or false: Hypermethylation of oncogenes can make cancer more likely:

false: HYPOMETHYLATION bc the cancerous gene is less silenced

True or false: Hypomethylation of tumor suppressor genes make cancer more likely:

false, HYPERMETHYLATION bc it silences the tumor protective genes

True or false: telomerase activity is lower than average in cancerous cells?

false, it is abnormally high

Protooncogenes=

normal genes, become oncogenes if they become mutated

Oncogenes=

abnormal genes; several must be activated to cause cancer

Antioncogenes=

suppress activation of oncogenes, turn them off

Temp control- negative feedback loop: -stimulus -sensor -control -effector

Stim: body being too hot Sensor: thermal receptors in brain Control: brain (HYPOTHALAMUS) Effector: sweat glands(sweat) or muscle (shiver if cold)

What is the ideal body weight for someone who is 167cm tall? eq. IBW=Ht-100

Ideal Body Wt (kg) = Ht (cm) -100 167-100= 67kg

Convert 24*C into *F. eq: F=(C*1.8) +32 C=(F-32) / 1.8 K= C+273

=75.2*F

Calc. amount of blood in L in woman whose wt is 72kg. Eq. men= 75mL/kg x wt(kg) women= 65mL/kg x wt (kg) infants= 80mL/kg x wt (kg)

=4,680mL =4.68L

Final - Exam 1 and New Bio Content Flashcards

(85 cards)