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Flashcards in Exam 1 Deck (178)
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1
Q

What are the waste products that are created from metabolism and enter into the venous system from the capillary bed?

A

CO2, H+, Heat, Urea

2
Q

What mechanism is the major control system of the body?

A

Negative Feedback mechanism.

3
Q

What four factors introduced in lecture influence glucose levels?

A
  • Insulin (primary)
  • Cortisol
  • Epinephrine
  • Glucagon
4
Q

What mechanism is characterized by the body perceiving a change in stimulus and amplifying this change?

A

Positive Feedback Mechanism

5
Q

What are two examples of positive feedback mechanisms?

A
  • Oxytocin induced uterine contraction via amplification via stretch of cervix
  • The clotting cascade
6
Q

What are positive feedback mechanism “checkpoints”? Give examples after defining.

A

These are “safety valves” that prevent the positive feedback mechanism from turning in to vicious cycles.

  • Birthing a baby that stops the oxytocin-induced uterine contractions.
  • Bleeding coagulation stops the clotting cascade from continuing.
7
Q

What ion spills from the intracellular fluid when tissue dies and causes further damage? What mechanism does this process exhibit?

A

Potassium; Pathologic positive feedback mechanism.

8
Q

How many cells does the body have? What proportion of these cells are red blood cells (RBCs) ?

A
  • 100 trillion cells
  • 25 trillion RBCs
9
Q

What is the pathology behind SIDS? What mechanism fails to cause this pathology?

A

SIDS occurs when a baby does not respond to elevated CO2 levels. This occurs because the baby lacks the necessary “safety valve” to increase respirations in response to increased CO2.

10
Q

Approximately how many nephrons do humans have at birth? What causes these to decrease over time and what mechanism is involved?

A

2 million nephrons
- damage occurs over time which decreases the number of nephrons which places further stress on the remaining nephrons. This is an example of a pathologic positive feedback mechanism and is exemplified in Diabetic Renal Inflammation.

11
Q

What type of bonds help proteins to hold their structures (folding and such)?

A

Sulphur bonds

12
Q

Describe the process required to get from proinsulin to insulin.

A
  • Proinsulin is the first protein created by the process of translation in the granular ER.
  • Proinsulin contains a folded insulin molecule and a C-peptide, all held together with peptide bonds.
  • The golgi apparatus takes this folded insulin and cleaves off the c-peptide and produces regular insulin.
13
Q

Does refined insulin contain a c-peptide molecule?

A

No, the c-peptide is cleaved when producing insulin from proinsulin.

14
Q

What are the components of the glycocalyx?

A

Glycolipids and glycoproteins

15
Q

What are cell “ID tags” and what are they composed of?

A

Cell ID tags are carb groups located on the outer portion of the cell membrane. These tags let the immune system know if the cell needs to be targeted or not.

16
Q

How does high blood glucose interface with cellular ID tags?

A
  • Hyperglycemia sticks extra glucose molecules to the carb groups and makes the cell ID tags “bad” this makes the immune system target these cells despite their health.
17
Q

Where are serine molecules located? What is the result if the location changes?

A

Serine molecules SHOULD be located intracellularly. If the serine molecule presents itself extracellularly, then the immune system targets the cell.

18
Q

What are Integral proteins usually pair to? What is the pairing’s purpose?

A

Integral proteins usually pair with intracellular peripheral proteins. This pairing allows the peripheral protein to “break off” and exert some function based on the interaction of an agonist with the integral protein.

19
Q

What is the relevance of a C=C (carbon-carbon double bond) in regards to the phospholipid bilayer?

A
  • The C=C bond makes the cell wall more fluid by “nudging” the cells away from each other.
  • This helps make the cells flexible (ex. RBCs)
20
Q

What is a micele and what is its significance?

A
  • Micele’s are phospholipid spheres that function as carrier objects to move hydrophobic drugs around a system. (Ex. Propofol)
21
Q

What is the process of lipid rescue?

A
  • This is a technique where a bunch of micele’s are given to hopefully capture a lipid soluble drug onto the carrier micele’s.
22
Q

How is cholesterol “grabbed” from the cell membrane?

A
  • The cholesterol has a hydroxyl group (-OH) that sticks out of the cell membrane and can be used as a point for other proteins to attach to and pull the entire cholesterol molecule out of the cell membrane.
23
Q

How much of cholesterol is ingested vs created by the body?

A
  • 20% of cholesterol is exogenously ingested.
  • 80% is produced endogenously.
24
Q

How is the process of cholesterol synthesis interrupted? What are the steps that led to the point of interruption?

A
  • Cholesterol synthesis is interrupted using Statins by inhibiting HMG-CoA reductase.
  • Acetyl-CoA & Acetoacetyl-CoA → HMG-CoA → HMG-CoA reductase 🔚 Statin
25
Q

Do statin’s have any benefits aside from reducing endogenous cholesterol production?

A

Yes, statins are also antiinflammatory.

26
Q

What the important cholesterol derivatives? Which of these derivatives are sex hormones?

A
  1. Progesterone
  2. Aldosterone (causes retention of Na+ and H20)
  3. Cortisol
  4. Estradiol
  5. Testosterone
  • Progesterone, estradiol and testosterone are sex hormones.
27
Q

What other molecule has a -OH “grabber” like cholesterol?

A

Arachidonic Acid

28
Q

Are saturated or polyunsaturated lipid fats considered better? Why?

A

Polyunsaturated fats are considered better because they make the cell wall more fluid and less rigid.

29
Q

What are the 4 phosphatidyl compounds?

A
  1. Phosphatidylinositol
  2. Phosphatidylserine
  3. Phosphatidylethanolamine
  4. Phosphatidylcholine
30
Q

What is the purpose of phosphatidylinositol?

A

Inositol is a signaling compound and does signaling by being phosphorylated 1-3 times, IP, IP2, IP3 (IP3 involved in smooth muscle).

31
Q

Which of the phosphatidyl compounds is an immune marker?

A

Phosphatidylserine

32
Q

What is the purpose of a flippase enzyme? What causes flippase to not work?

A
  • Flippase “flips” extracellular serine back to an intracellular position.
    • ATP shortages or cell death can cause this enzyme to not work.
33
Q

In what system is phosphatidylethanolamine pertinent?

A

The nervous system.

Thought to be important for cell division and replication.

34
Q

What are the two purposes of phosphatidylcholine?

A
  • PCh is stored in the cell wall as a precursor to ACh, to be “grabbed” when needed.
  • Pertinent at the neuromuscular junctions and for nerve signaling.
35
Q

Does cholesterol make the cell wall more fluid?

A

No, it makes the cell wall more rigid.

36
Q

What is sphingomyelin? Where is it pertinent?

A
  • sphingomyelin is a myelin precursor which is important as insulation for the nerve sheath for nerve signaling.
37
Q

In the AA pathway out of PGG2 and PGH2 which of the two prostaglandins comes first and which is more stable?

A
  • PGG2 comes first (AA → COX 1 & 2 → PGG2 → PGH2)
    • PGG2 is unstable and has to be converted to PGH2 to be useful.
38
Q

Between COX1 and COX2, which one is related more to pain?

A

COX2

39
Q

What converts phospholipids into arachidonic acid?

A

PhospholipaseA2. This enzyme can be inhibited by corticosteroids.

40
Q

What component of AA metabolism is the allergy response pathway? What is the main enzyme that starts this pathway?

A
  • Leukotriene pathway
  • 5-LipoOxygenase (LOX)
41
Q

Where do your Leukotriene receptor antagonists work in regards to the AA metabolism pathway?

A

AA → 5-LOX → 5-HPETE → LTA4

Lukast drugs work to inhibit at the LTA4 level.

42
Q

Where does Aspirin inhibit the AA pathway?

A

At the COX1 and COX2 level.

43
Q

What characteristic do all of the prostaglandin (PGH2) derivatives share? Which of the PGH2 derivatives are particularly important and why?

A
  • All prostaglandin derivatives are proinflammatory.
    • TXA2 is most important and activates coag cascade and causes vasoconstriction.
    • PGI2 promotes anticoagulation and vasodilation.
    • PGE2 mediates fever and pain.
44
Q

What are the negative attributes of COX inhibition?

A
  • Worsening of heart disease by inhibiting PGI2 but not TXA2. This causes increased endothelial clotting essentially.
  • The kidneys are affected microvascularly in much the same way as the heart.
45
Q

What organ has relevance in regards to cytochrome P450 in the AA pathway?

A

Liver

46
Q

What is the normal serum Na+ level and what is its concentration gradient?

A

140-150 mEq/L and the gradient is 10:1 with most Na+ being extracellular

47
Q

What is the normal serum K+ level and what is it’s concentration gradient?

A

Serum K+ = 4 mEq/L, and it’s concentration gradient is 1:35 favoring the ICF.

48
Q

Where is Ca2+ stored intracellularly, what are the functions of Ca2+, and what is its gradient?

A
  • Stored in ER
  • Signaling compound that “turns” cell on
  • Gradient is 10,000 : 1 favoring the ECF.
49
Q

What is the function of Mg2+ and what should we know about its gradient?

A
  • Antagonizes Ca2+ by competing for its receptor sites.
  • More Mg2+ is present in the ICF.
50
Q

What should we know about Cl- and it’s concentration gradient?

A
  • Chloride follows Na+
  • Much higher concentration outside than inside (because it follows Na+?)
51
Q

What should be known about phosphate compounds (HPO4 & H2PO4-) and their gradient?

A
  • Phosphates are used inside cell for energy (ATP) and as signaling compounds.
  • More Phosphate is intracellular than extracellular
52
Q

What other molecule functions in much the same way as ATP?

A

GTP (Guanine TriPhosphide)

53
Q

What is Phosphocreatine and what should be known about it?

A
  • Phosphocreatine is a high energy phosphorylated creatine molecule.
  • Phosphocreatine replenishes ADP to ATP
  • Helps in high energy activities (lifting weights, sprints, etc)
54
Q

Are amino acids primarily located intracellularly or extracellularly?

A

Intracellularly

55
Q

Is creatine located mainly intracellularly or extracellularly?

A

Intracellularly

56
Q

What should be known about lactate?

A
  • Lactate is a product of metabolism
  • In normal conditions, is located primarily intracellularly.
57
Q

What is the normal serum concentration of glucose and is it located in the ECF or ICF?

A
  • 60-100 mg/dL
  • Glucose is located primarily extracellularly.
58
Q

What structure prevents proteins from leaking out of the body’s plasma?

A

The capillary system of the cardiovascular system.

59
Q

What is the ≈ Total mOsm/L serum concentration? What does the Total mOsm/L respresent?

A
  • 300 is the total mOsm/L concentration.
  • This represents the total amount of solutes dissolved in a L of plasma (serum).
60
Q

What differentiaties Total mOsm/L and corrected mOsm/L ?

A
  • Some solutes act as individual molecules rather than separate (I.e. Na+ and CL- grouping together)
61
Q

What is Total Osmotic Pressure and what is an example of its relevance?

A
  • Contributes to movement of solutes across capillary membrane
  • Very high, 5400 mmHg
  • Think of issues of ⇣ Na+ and the blood brain barrier.
62
Q

Describe the process that results in ATP degrading into adenosine and then “leaking” out of the cell?

A

Adenosine can leak out of the cells when all of its phosphate’s have been used up.

ATP → ADP → AMP → Adenosine.

This happens during ischemic/anoxic conditions of the cells and results in massive issues due to adenosine being replaced very slowly.

63
Q

How many different “forms” of mitochondria are there?

A

20-40

64
Q

Where does mitochondrial DNA come from?

A

All mitochondrial DNA is inherited from your mother’s side.

65
Q

Describe the Krebs cycle in big steps. Where does this take place?

A
  1. Anaerobic metabolism produces 2ATP from glucose in the cytoplasm
  2. Pyruvate leftover of anaerobic metabolism goes to mitochondria
  3. Pyruvate and O2 are used to create 34 ATP. (Aerobic respiration)
66
Q

What are peroxisomes and in broad strokes, what do they do?

A

A peroxisome is an oxidative organelle that uses oxidative stress to destroy unwanted things using catalase to oxidize foreign material, bacteria, etc.

67
Q

What is an example of peroxisomes in use?

A

When EtOH is ingested, peroxisomes in the liver destroy the molecule producing ethylaldehyde.

68
Q

Where do Lysosomes come from and what is their purpose?

A
  • Lysosomes are produced in the golgi apparatus.
  • Lysosomes “digest” bacteria and degraded proteins.
69
Q

How do Lysosomes perform their duties?

A
  • Lysosomes digest degraded proteins and bacteria through hydrolysis using hydrolase.
  • This requires an acidic environment, pH = 5
70
Q

Where might lysosomes be located to help break down food products? What would happen if a bunch of lysosomes died?

A
  • GI cells to break down food products and move the nutrients onward.
  • If a bunch of lysosomes died it could spill a bunch of acid into a cell’s environment making it acidic.
71
Q

What are the 3 functions of the Glycocalyx?

A
  1. ID Tags.
  2. Gel insulating layer.
  3. Repel or attach to other cells.
72
Q

How much of the human body (70kg) is water?

A
  • 60% or 42kg = 42L
73
Q

How much of the water in the human body (70kg) is in the ICF? ECF?

A
  • ICF = 28L
  • ECF = 14L
74
Q

What are the two components of the body’s ECF? (assuming 70kg person)

A
  • Intersitial Fluid ≈ 11L
  • Blood Plasma ≈ 3L
75
Q

What are the carrier proteins for cholesterol?

A

HDL, VDL, and LDL

76
Q

What gas moves into the cell by simple diffusion by a concentration gradient? Why does the concentration gradient exist for this gas? What gas moves out by comparison?

A
  • Oxygen moves into the cell.
  • Oxygen moves intracellular because intracellular O2 is used up.
  • CO2 moves out extracellularly as O2 is used up.
77
Q

What’s an example of channel proteins using simple diffusion? Why might some molecules even need this channel protein?

A
  • Channel proteins are needed for charged ions such as Na+ and K+.
  • Channel proteins will allow intracellular K+ to move along its gradient to become extracellular.
  • Channel proteins will allow extracellular Na+ to move along its gradient to become intracellular.
78
Q

What is an example of facilitated diffusion and what are its characteristics?

A
  • Glucose being brought from the ECF to the ICF via a carrier molecule using a carrier protein.
  • Facilitated Diffusion characteristics:
    • No energy consumed
    • Down gradient still
    • Carrier protein necessary.
79
Q

What is the hallmark attribute of Active Transport across the cell membrane?

A

The use of ATP (energy)

80
Q

Describe the Na+/K+ pump. What is the purpose of ATPase in this process? What is the purpose of the pump in general?

A
  • The sodium-potassium pump uses 1 ATP to pull 2 K+ ions Intracellularly and push 3 Na+ ions extracellularly.
  • This is very energy intensive and ATPase is the enzyme that pulls off the phosphate group for the energy.
  • The purpose of this pump is to maintain all cellular concentration gradients across the whole body. Incredibly important.
81
Q

Describe ion protein channels? What characterizes the selectivity of these channels? Give an example of one of these.

A
  • These are channels used to selectively allow certain ions to passively go through.
  • Selectivity is based on size and charge.
  • K+ “leak” channels where K+ leaks through but Na+ does not.
82
Q

What characterizes secondary active transport? Does this process use ATP directly?

A
  1. Secondary active support uses a co-transport (or symporter) to move a molecule across and electrochemical gradient.
  2. Ex. Na+ binding to a protein to help pull across a glucose molecule.
  3. No ATP is used directly for this method. (It’s active because it uses the natural Na+ gradient created by the Na+/K+ ATPase pump.
83
Q

What characterizes Ion/Compounder Exchange Proteins? What are they also known as? Give an example.

A
  • Ion/Compounder Exchange Proteins are characterized by exchanging one ion for another (or a compound).
  • They are also called Antiporters or Counter-transporters.
  • An example is exchanging 1 intracellular Ca2+ for 3Na+ to maintain the extracellular Ca2+ gradient.
84
Q

Which of the Leukotriene derivates are related to bronchospasm?

A
  • LTC, LTD, LTE
85
Q

What is the end result on the cell membrane of the Na+/K+/ATPase pump and how does it achieve this?

A

The end result is an electronegative ICF near the cell membrane. It achieves this by use 1 ATP to pump 3 Na+ out and 2 K+ in against their concentration gradients.

86
Q

How is the Na/K/ATPase pump a “cell diuretic”?

A

By pumping out an 3Na+ ions, the pump causes water to follow the Na and keeps the cell from becoming edematous.

87
Q

Is intracellular or interstitial edema easier to fix? why?

A

interstitial is easier to fix and can be done by using a diuretic to pull the extra fluid out of the tissues.

Intracellular is much harder and requires finding the root of the problem and fixing that.

88
Q

What causes sweat to be salty?

A

Na+ is pumped out of cells so that water will follow, the resulting mixture is understandably salty.

89
Q

What transport proteins are insulin dependent? Where are they located?

A

GLUT-4 Transport proteins, they are located in the skeletal muscle, fat, and liver.

90
Q

What would be the result of more GLUT-4? Less? How can these transport proteins be manipulated? What would activation of more GLUT-4 do to your serum glucose levels?

A
  1. More GLUT-4 results in more glucose being transported while the inverse would be true with less GLUT-4.
  2. More of these transport proteins can be activated via insulin
  3. The higher activation and movement (and thus use, usually) of glucose from the ECF leads to lower serum glucose levels.
91
Q

Where are GLUT-2 transport proteins found? How do they differ from GLUT-4?

A
  • Pancreatic beta cells primarily (also liver and intestines)
  • Insulin-independent
  • Always “on” via facilitated diffusion
92
Q

What should be known about GLUT-1 transport proteins?

A
  • Found in neurons
  • Always “on”.
  • Generally insulin independent, but can be affected with lots of insulin.
93
Q

Why does glucose need transport proteins? by what method does glucose move in to the cells?

A
  • Glucose needs transporters due to its hydrophillic nature (glucose has multiple hydroxyl groups).
  • Facilitated Diffusion
94
Q

Between facilitated and simple diffusion, which is affected by the Vmax ? Explain why.

A

Facilitated diffusion is affected by Vmax

Essentially, Vmax occurs when all transport proteins are moving a drug/ligand/substance and no more transport proteins are available to “facilitate” the diffusion.

95
Q

What are the 9 factors that determine diffusion rate? If all these factors were put under an umbrella as 2 factors affecting diffusion rate, what would these 2 be called?

A
  1. [] inside vs. outside
  2. Membrane (lipid) solubility
  3. Particle size
  4. Pore size
  5. # of pores available
  6. Heat (i.e. kinetic movement)
  7. Physical pressure
  8. Electrical charge
  9. Chemical gradient

1- Electrochemical gradient and

2- Membrane permeability

96
Q

1 mOsm/L = _____ mmHg ?

A

19.3

97
Q

Where are GLUT-4 transporters located? Are these transporters insulin-dependent or independent? What does insulin-dependent mean?

A
  1. Skeletal muscle, adipose tissue, and the liver.
  2. GLUT-4 is dependent
  3. Insulin Dependence means that:
    1. Insulin is given → more GLUT-4 Transporters are activated → More glucose is moved from ECF to ICF.
98
Q

What mechanism is broken in the pathophysiology of Type II Diabetes?

A
  • Any part of the process in: InsulinIns receptor → GLUT-4 → Glucose pumps.
99
Q

Where are proteins produced inside the cell? (not the process, just the specific place of production)

A

Granular (rough) endoplasmic reticulum (specifically by the ribosomes attached to the ER)

100
Q

Where are lipids produced inside the cell? (not the process, just the specific place of production)

A

Agranular (smooth) endoplasmic reticulum

101
Q

Where do the instructions for protein production come from?

A

The cell nucleus

102
Q

Where are ribosomes located and what is their function?

A
  • Ribosomes are located on the granular ER (95%) and floating in the cytoplasm (5%).
  • Ribosomes take instructions from the nucleus and create proteins.
103
Q

What organelle manages larger proteins, folding them and packaging them for secretion?

A

Golgi apparatus

104
Q

What cell organelle carries proteins from the golgi apparatus to the cell membrane to be secreted?

A

Secretory Vesicles

105
Q

How do secretory vesicles differ from transport vesicles?

A

Secretory vesicles carry proteins from the golgi apparatus to the cell membrane; transport vesicles take proteins from the endoplasmic reticulum to the golgi apparatus.

106
Q

What are proteins composed of? Where do these components come from? How are these components combined to form proteins?

A
  • Amino acids form proteins and come primarily from our diet. Amino acids are combined end to end to form proteins.
107
Q

What is the term for small proteins?

A

peptides

108
Q

The Nuclear envelope is has how many layers? What organelle is attached to the nuclear membrane, making up a portion of its structure?

A

The nuclear membrane has two layers with the granular endoplasmic reticulum directly attached to the nuclear envelope.

109
Q

What is the “messenger” for creation of proteins?

A

RNA, specifically mRNA

110
Q

What is used as a “template” to create mRNA? What is the name of this process? Where does this process occur?

A

DNA is template for creating mRNA; it does so in the nucleus and the process is called transcription.

111
Q

Where does the process of translation occur? What organelles are involved and what is the end product?

A

Translation occurs with ribosomes utilizing the mRNA. The purpose of this process to create various proteins with a myriad of functions.

112
Q

What are the two main functions of proteins in regards to the homeostasis of cells?

A

Proteins function to create cell structure and as cell enzymes.

113
Q

Endoplasmic reticulum vesicles are also known as _______.

A

Transport vesicles.

114
Q

What organelle is most necessary for total cell replication?

A

Nucleus

115
Q

What pump is the primary source of the cell membrane’s electrochemical gradient? How does this pump work to create said gradient?

A

The Na+/K+/ATPase Pump

  • The pump moves 3 Na+ ions to the ECF.
  • The pump moves 2 K+ ions into the ICF.

In doing this, we are left with a net (-) charge on the inside of the cell membrane.

116
Q

In addition to maintenance of the cell’s electrochemical gradient, what other important function does the Na/K/ATPase pump serve?

A

The pump serves as a “cell diuretic”.

  • By moving an extra Na+ ion outside of the cell, this causes H2O to follow.
  • Keeps cell from getting swollen
117
Q

What is normal Vrm ?

A

-70mV to -80mV

118
Q

What is the most important ion in regards to Vrm ? Why?

A

K+ is the most important ion

continual loss of K+ through leak channels and by the Na/K/ATPase pump causes the cell’s membrane interior to be electrochemically negative ( - )

119
Q

Why is normal Vrm = -80mV ?

A

Normal Vrm is -80mV due to the EK+ (equilibrium potential) being the main contributor of electronegativity. Other ions bring the expected -94mV to around -80mV.

120
Q

What is “Depolarization”? What occurs to during Depolarization itself? What is the purpose of Depolarization?

A
  1. Depolarization is the changing of the cell membrane from (-) to more (+).
  2. Depolarization: A stimulus causes a rapid influx of Na+ that make the cell interior more (+).
  3. Depolarization essentially turns the cell “on” or increases cell activity in some way.
121
Q

What are graded potentials?

A

Graded potentials are stimuli that do not meet the threshold needed for an action potential initiation.

122
Q

Label the letters in this theoretic Action Potential graph. What does the pink line denote?

A

A. Vrm (resting membrane potential)

B. Stimulus (pain, scent, touch, etc.)

C. Rapid Depolarization (fast V-G Na+ ion channels)

D. Depolarization peak (slightly positive usually)

E. Repolarization (AbsoluteRF)

F. Hyperrepolarization (RelativeRF)

G. Return to Vrm

The pink line is the mV threshold needed to initiate depolarization.

123
Q

What happens to the permeability of Na+ (pNa+) during depolarization? What does this do to the cell’s interior?

A

pNa+ increases via opening of membrane Na channels.

This causes the cellular interior to become more (+).

124
Q

What is responsible for the prolonged cardiac action potential peak?

A

L-Type Voltage Gated Ca2+ channels allowing an influx of Ca2+.

125
Q

What gate is activated at peak depolarization? What activated this gate?

A
  • The H-gate closes at peak depolarization (+20mV - 30mV).
  • This occurred due to the time delay nature of V-G Na+ channels.
126
Q

Which gate is closed during the Absolute Refractory Period? Which part of the action potential graph would this correspond with?

A

The H-Gate is closed during the ARP.

This would be represented by the downward stroke on the action potential graph until the threshold is passed and hyper-repolarization occurs.

127
Q

What two channel types are primarily responsible for Action Potentials? What channel is responsible for the return to Vrm ?

A
  • V-G Na+ Channels and V-G K+ Channels
  • The Na+K+ATPase pump is primarily responsible for maintenance of Vrm
128
Q

What causes the V-G K+ Channel to open?

A
  • Na+ ion concentration causing the membrane polarity to be +. This causes the K+ gates (which are + themselves) to be repelled.
129
Q

In addition to the Na+K+ATPase pump, what else contributes to the electric gradient of the cell membrane? How?

A

Leaky K+ channels allow K+ to flow out of the cell down their concentration gradient increasing the + nature of the ECF.

130
Q

What is an action potential?

A

The dominoe like effect of Na+ moving into the cell and causing more Na+ to spill into adjacent areas and so on and so forth.

131
Q

What HR do we consider normal for A&P? What would this heart rate be without parasympathetic activity?

A
  • 72 bpm
  • 100 bpm without parasympathetic activity.
132
Q

What structure adds to the electronegativity of the cellular membrane, aside from the Na+K+/ATPase pump? How?

A

K+ leak channels add to the electrochemically negative gradient of the cell by letting additional K+ ions leak from the cell making the ECF more + and the ICF more -

133
Q

What is Vrm ? How is it calculated?

A
  • Vrm is resting membrane potential
  • Vrm = ± 61 x log ( [] ICF / [] ECF )
    • if anion
    • if cation
134
Q

What are the subunits of the Adult NMJ nACh receptors?

A
  • Alpha-1 x 2
  • Beta-1
  • Delta
  • Epsilon
135
Q

In broad strokes, what is the process for how adult NMJ nACh receptor works? What does this process initiate?

A
  1. ACh binds to two subunits.
  2. This binding causes the m-gate to open exposing the (-) charged pore.
  3. Na+ floods through pore due to charge and concentration gradient.
  4. H-gate closes due to time delay (no outside stimulus), preventing further ion movement.

Action potential initiation

136
Q

How do Schwann cells insulate axon’s? Is this CNS or PNS?

What is the outermost wrapping of the Schwann cell called?

A
  • Schwann cells form a wrapping myelin sheath that squeezes out water from around the axoplasm to provide insulation and prevention of loss of signal, electrons, and ions.
  • Schwann cells insulate axons in the PNS.
  • The outermost wrapping is called the Neurolemma
137
Q

What are the subunits of the Adult NMJ nACh receptors? Where does binding of ACh occur?

A
  • alpha-1 x 2
  • Beta-1
  • delta
  • epsilon

Binding occurs on the two alpha-1 units. (in particular at the alpha1-delta and alpha1-epsilon junctions.)

138
Q

What proteins make up Gap Junctions? What is their purpose? Are these junctions unidirectional?

A
  • Gap Junctions are composed of 6 Connexin proteins that form a Connexon.
  • Connexon’s allow free flow of ion’s between adjacent cells for muscular or neurological action potential transmission.
  • Gap Junctions are bidirectional meaning a signal can pass both ways with very low resistance.
139
Q

What are the 4 most common causes of demyelinating disease?

A
  1. Genetics
  2. Infection
  3. Autoimmune hyperreactivity
  4. Polyneuropathies
140
Q

What is Multiple Sclerosis? What are some of the hallmark signs/symptoms? Is modern treatment effective? If untreated, how does death occur?

A
  • Multiple Sclerosis is a Central Nervous System disease of demyelination occurring throughout the white matter of the brain.
  • S/S: Loss/alteration of sensory inputs and gross motor deficits
  • MS is much better treated with modern treatments.
  • Death usually occurs when loss of function of the diaphragm occurs.
141
Q

What is Guillan Barre Syndrome (GBS)? What usually causes this syndrome? Do most cases resolve? Are there any treatments? What is the initial symptom usually and what s/s follow? What causes in death in severe cases?

A
  • GBS is a demyelinating disease of the PNS (Peripheral Nervous System)
  • GBS is often caused by overreaction of the immune system to an infection or from a vaccine.
  • Most cases resolve in 3-4 weeks but 5% of cases are permanent.
  • Treatment is usually plasmapheresis, but NOT steroids.
  • “Flu-like” symptoms occur first with loss of muscle tone following
    • Death is usually caused by loss of respiratory drive or loss of larynx control leading to aspiration.
142
Q

What is the energy usage of white matter in the brain (as a percentage)? Is this efficient? What causes this efficiency?

A

20%

This efficiency is the direct result of myelination preventing loss of Na+ through the phospholipid bilayer.

143
Q

What are the categories of neuron myelination from most myelinated to least myelinated?

A
  • A - Most
  • B - Intermediate
  • C - Least
144
Q

Place these Neurons from Category A in order from fastest to slowest:

  • Aγ (A-Gamma)
  • Aβ (A-Beta)
  • Aα (A-Alpha)
  • Aδ (A-Delta)
A
  1. Aα (A-Alpha)
  2. Aβ (A-Beta)
  3. Aγ (A-Gamma)
  4. Aδ (A-Delta)
145
Q

What are Aδ (A-Delta) neurons primarily used for?

A

Fast pain transmission

146
Q

What are Aα (A-alpha) neurons primarily used for?

A

Motor neuron transmission

147
Q

What should be known about Category C neurons? What do they ennervate? What sensory information do these neurons transmit?

A
  • Unmyelinated
  • Smaller and slower
  • Spinal cord to ANS ennervation.
  • These neurons transmit:
    • Aching slow pain
    • Temperature
    • Crude touch and pressure
148
Q

What anatomical feature determines if an action potential is transmitted down the axon from the dendritic portion of the neuron?

A

The axon hillock

149
Q

How many Glial cells are there in comparison to Neurons?

A

10 glial cells for every 1 neuron.

150
Q

What cell is the most common glial cell?

A

Astrocytes

151
Q

What are the 4 functions of astrocytes?

A
  1. Determination of composition of CSF
  2. CNS repair
  3. Recycling of Neurotransmitters
  4. Regulation of Blood Brain Barrier.
152
Q

What glial cell produces CSF? Where is it located? What pump in these cells produces CSF?

A
  • Ependymal cells produce CSF (through network called choroid plexus).
  • They are located throughout the entirety of the brain and spinal cord.
  • CSF is produced by Na+ pumps
153
Q

What cells form the myelin sheath in the CNS?

A

Oligodendrocytes

154
Q

What cells are the “vacuum cleaners” of the CNS? What does this mean?

A

Microglial cells; these cells act as macrophages of the CNS and clear virus, bacteria, etc.

155
Q

What structure located in the cell membrane is responsible for the unidirectional nature of action potentials? Why?

A
  • Voltage Gated Na+ Channels.
  • These channels propagate a signal from the axon hillock towards the axon terminal.
156
Q

What are the subunits of the Adult NMJ nACh receptors?

A
  • Alpha-1 x 2
  • Beta-1
  • Delta
  • Epsilon
157
Q

In broad strokes, what is the process for how adult NMJ nACh receptor works? What does this process initiate?

A
  1. ACh binds to two subunits.
  2. This binding causes the m-gate to open exposing the (-) charged pore.
  3. Na+ floods through pore due to charge and concentration gradient.
  4. H-gate closes due to time delay (no outside stimulus), preventing further ion movement.

Action potential initiation

158
Q

How do Schwann cells insulate axon’s? Is this CNS or PNS?

What is the outermost wrapping of the Schwann cell called?

A
  • Schwann cells form a wrapping myelin sheath that squeezes out water from around the axoplasm to provide insulation and prevention of loss of signal, electrons, and ions.
  • Schwann cells insulate axons in the PNS.
  • The outermost wrapping is called the Neurolemma
159
Q

What are the subunits of the Adult NMJ nACh receptors? Where does binding of ACh occur?

A
  • alpha-1 x 2
  • Beta-1
  • delta
  • epsilon

Binding occurs on the two alpha-1 units. (in particular at the alpha1-delta and alpha1-epsilon junctions.)

160
Q

What proteins make up Gap Junctions? What is their purpose? Are these junctions unidirectional?

A
  • Gap Junctions are composed of 6 Connexin proteins that form a Connexon.
  • Connexon’s allow free flow of ion’s between adjacent cells for muscular or neurological action potential transmission.
  • Gap Junctions are bidirectional meaning a signal can pass both ways with very low resistance.
161
Q

What are the 4 most common causes of demyelinating disease?

A
  1. Genetics
  2. Infection
  3. Autoimmune hyperreactivity
  4. Polyneuropathies
162
Q

What is Multiple Sclerosis? What are some of the hallmark signs/symptoms? Is modern treatment effective? If untreated, how does death occur?

A
  • Multiple Sclerosis is a Central Nervous System disease of demyelination occurring throughout the white matter of the brain.
  • S/S: Loss/alteration of sensory inputs and gross motor deficits
  • MS is much better treated with modern treatments.
  • Death usually occurs when loss of function of the diaphragm occurs.
163
Q

What is Guillan Barre Syndrome (GBS)? What usually causes this syndrome? Do most cases resolve? Are there any treatments? What is the initial symptom usually and what s/s follow? What causes in death in severe cases?

A
  • GBS is a demyelinating disease of the PNS (Peripheral Nervous System)
  • GBS is often caused by overreaction of the immune system to an infection or from a vaccine.
  • Most cases resolve in 3-4 weeks but 5% of cases are permanent.
  • Treatment is usually plasmapheresis, but NOT steroids.
  • “Flu-like” symptoms occur first with loss of muscle tone following
    • Death is usually caused by loss of respiratory drive or loss of larynx control leading to aspiration.
164
Q

What is the energy usage of white matter in the brain (as a percentage)? Is this efficient? What causes this efficiency?

A

20%

This efficiency is the direct result of myelination preventing loss of Na+ through the phospholipid bilayer.

165
Q

What are the categories of neuron myelination from most myelinated to least myelinated?

A
  • A - Most
  • B - Intermediate
  • C - Least
166
Q

Place these Neurons from Category A in order from fastest to slowest:

  • Aγ (A-Gamma)
  • Aβ (A-Beta)
  • Aα (A-Alpha)
  • Aδ (A-Delta)
A
  1. Aα (A-Alpha)
  2. Aβ (A-Beta)
  3. Aγ (A-Gamma)
  4. Aδ (A-Delta)
167
Q

What are Aδ (A-Delta) neurons primarily used for?

A

Fast pain transmission

168
Q

What are Aα (A-alpha) neurons primarily used for?

A

Motor neuron transmission

169
Q

What should be known about Category C neurons? What do they ennervate? What sensory information do these neurons transmit?

A
  • Unmyelinated
  • Smaller and slower
  • Spinal cord to ANS ennervation.
  • These neurons transmit:
    • Aching slow pain
    • Temperature
    • Crude touch and pressure
170
Q

What anatomical feature determines if an action potential is transmitted down the axon from the dendritic portion of the neuron?

A

The axon hillock

171
Q

How many Glial cells are there in comparison to Neurons?

A

10 glial cells for every 1 neuron.

172
Q

What cell is the most common glial cell?

A

Astrocytes

173
Q

What are the 4 functions of astrocytes?

A
  1. Determination of composition of CSF
  2. CNS repair
  3. Recycling of Neurotransmitters
  4. Regulation of Blood Brain Barrier.
174
Q

What glial cell produces CSF? Where is it located? What pump in these cells produces CSF?

A
  • Ependymal cells produce CSF (through network called choroid plexus).
  • They are located throughout the entirety of the brain and spinal cord.
  • CSF is produced by Na+ pumps
175
Q

What cells form the myelin sheath in the CNS?

A

Oligodendrocytes

176
Q

What cells are the “vacuum cleaners” of the CNS? What does this mean?

A

Microglial cells; these cells act as macrophages of the CNS and clear virus, bacteria, etc.

177
Q

What structure located in the cell membrane is responsible for the unidirectional nature of action potentials? Why?

A
  • Voltage Gated Na+ Channels.
  • These channels propagate a signal from the axon hillock towards the axon terminal.
178
Q

What structure located in the cell membrane is responsible for the unidirectional nature of action potentials? Why?

A
  • Voltage Gated Na+ Channels.
  • These channels propagate a signal from the axon hillock towards the axon terminal.