Chapter 1 Flashcards
1
Q
What is the total amount of fluid or water called?
A
Total Body Water
2
Q
What percentage accounts for 50%-70% of body weight
A
Total Body Water
3
Q
Total Body water is a higher percentage of body weight when body fat is low and a lower percentage when body fat is high. T/F
A
True
4
Q
What are the two major body fluid compartments?
A
ICF (Intracellular fluid) and ECF (extracellular fluid)
5
Q
What is contained within the cell and is two-thirds of total body water?
A
ICF
6
Q
What is outside of the cell and is one-third of total body water?
A
ECF
7
Q
What two compartments is ECF further divided into?
A
Plasma and Interstitial fluid
8
Q
What is plasma?
A
The fluid circulating in the blood vessels and is smaller of the two ECF sub-compartments.
9
Q
What is interstitial fluid?
A
The fluid that actually bathes the cells and is the larger of the two sub-compartments.
10
Q
What fluids are separated by the capillary wall?
A
Plasma and interstitial fluid.
11
Q
What is an ultra filtrate of plasma, which is formed by filtration processes across the capillary wall?
A
Interstitial fluid
12
Q
T/F The capillary wall is virtually impermeable to large molecules such as plasma proteins, interstitial fluid contains little, if any, protein.
A
True
13
Q
T/F The composition of the body fluids is not uniform.
A
True
14
Q
Amounts of solute are expressed in?
A
Moles, equivalents, or osmoles.
15
Q
Concentrations of solutes are expressed in?
A
Moles per liter.
16
Q
An equivalent is used to describe?
A
The amount of charged (ionized) solute is the number of moles of the solute multiplies by its valence.
17
Q
One osmole is?
A
the number of particles into which a solute dissociates in solution.
18
Q
Osmolarity is?
A
the concentration of particles in solution expressed as osmoles per liter.
19
Q
T/F If a solute does not dissociate in solution, then its osmolarity is equal to its molarity.
A
True
20
Q
T/F If a solute dissociates into more than one particle in solution then its osmolarity equals the molarity multiplied by the number of particles in solution.
A
True
21
Q
pH is?
A
A logarithmic term that is used to express hydrogen (H+) concentration.
22
Q
The major cation in_____ is sodium (Na+), and the balancing anions are chloride (Cl-) and bicarbonate (HCO3-)
A
ECF
23
Q
The major cations in_____is Potassium (K+) and magnesium (Mg2+) and the balancing anions are proteins and organic phosphates.
A
ICF
24
Q
T/F ICF is more acidic (has a lower pH) than ECF.
A
True
25
T/F Substances found in high concentration in ECF are found in low concentration in ICF, and vice versa.
True
26
T/F The total solute concentration (osmolarity) is the same in ICF and ECF.
True; this equality is achieved because water flows freely across cell membranes. Any transient differences in osmolarity that occur between ICF and ECG are quickly dissipated by water movement into or out of cells to reestablish the equality.
27
T/F The differences in solute concentration across cell membranes are created and maintained by energy consuming transport mechanisms in the cell membranes/
True
28
T/F Is is critically important that cell membranes are NOT freely permeable to all substances but, rather, have selective permeabilities that maintain the concentration gradients established by energy- consuming transport processes.
True
29
What is the most significant difference in composition between interstitial fluid and plasma?
Presence of proteins.
30
T/F Plasma proteins do not readily cross capillary walls because of their large molecular size and therefore are excluded from interstitial fluid.
True
31
What is Gibbs-Donnan equilibrium?
The plasma proteins are negatively charged, and this negative charge causes a redistribution of small, permeant cations and anions across the capillary wall.
32
The Gibbs- Donnan Equilibrium can be explained as?
The plasma compartment contains the impermeant, negatively charged proteins. Because of the requirement for electronegativity, the plasma compartment must have a slightly lower concentration of small anions (e.g. Cl-) and a slightly higher concentration of small cations (e.g. Na+, K+) than that of interstitial fluid.
33
The small concentration difference for permeant ions is expressed in what ratio?
The Gibbs- Donnan ratio which gives the plasma concentration relative to the interstitial fluid concentration for anions and interstitial fluid relative to plasma for cations.
34
What are cell membranes primarily composed of?
Lipids and proteins
35
What does the lipid component (in cell membranes) consist of?
Phospholipids, cholesterol, and glycolipids
36
What is the lipid component (in cell membranes) responsible for?
Responsible for the high permeability of cell membranes to lipid-soluble substances such as carbon dioxide, oxygen, fatty acids, and steroid hormones. It is also responsible for the low permeability of cell membranes to water- soluble substances such as ions, glucose, and amino acids.
37
What does the protein component of the cell membrane consist of?
Transporters, enzymes, hormone receptors, cell-surface antigens, and ion and water channels.
38
What do Phospholipids consist of?
Phosphorylated glycerol backbone ("head") and two fatty acid ("tails").
39
The glycerol backbone of the phospholipid is_______.
Hydrophilic (water soluble)
40
The fatty acid tails of the phospholipid is______.
Hydrophobic (water insoluble)
41
The phospholipid molecules have both hydrophilic and hydrophobic properties so they are called?
Amphipathic
42
In cell membranes, phospholipids orient so that the lipid soluble fatty acid tails face each other and the water- soluble glycerol heads point away from each other, dissolving in the aqueous solutions fo the ICF or ECF...which creates a______.
Lipid Bilayer.
43
_____ in cell membranes may be either integral or peripheral, depending on whether they span the membrane or whether they are present on only one side.
Proteins
44
The distribution of proteins in a phospholipid bilayer is illustrated in the______.
Fluid Mosaic Model
45
_____ ____ _____ are embedded in, and anchored to, the cell membrane by hydrophobic interactions.
Integral Membrane Proteins.
46
How do you remove an integral protein from the cell membrane?
Its attachments to the lipid bilayer must be disrupted (by a detergent).
47
What are transmembrane proteins?
Integral proteins which span the lipid bilayer one or more times. They are actually in contact with the ECF and ICF.
48
What are some examples of transmembrane integral proteins?
Ligand- binding receptors. (e.g. for hormones or neurotransmitters), transport proteins (e.g., Na+-K+ ATPase), pores, ion channels, cell adhesion molecules, and GTP- binding proteins.
49
What are the second and third categories of integral membrane proteins?
A second category of integral proteins is embedded in the lipid bilayer of the membrane but does not span it. A third category of integral proteins is associated with membrane proteins but is not embedded in the lipid bilayer.
50
What are peripheral membrane proteins?
They are not embedded in the membrane and are not covalently bound to cell membrane components. They are loosely attached to either the intracellular or extracellular side of the the cell membrane by electrostatic interactions and can be removed with mild treatments that disrupt ionic or hydrogen bonds.
51
T/F Substances may be transported down an electrochemical gradient (downhill) or against an electrochemical gradient (uphill)
True
52
____ transport occurs by diffusion, either simple or facilitated and requires no input of metabolic energy.
Downhill
53
_____ transport occurs by active transport, which may be primary or secondary.
Uphill
54
Primary active transport requires a _____ input of metabolic energy; secondary active transport utilizes an ____ input of metabolic energy.
Direct; Indirect
55
T/F Simple diffusion is the only form of transport that is NOT carrier mediated.
True
56
T/F Facilitated diffusion, primary active transport, and secondary active transport all involve integral membrane proteins and are called carrier-mediated transport.
True; all forms of carrier-mediated transport share the following three features: Saturation, stereospecificity, and competition.
57
What is Saturation?
Saturabilty is based on the concept that carrier proteins have a limited number of binding sites for the solute.
58
What is the transport maximum (Tm)?
When all of the binding sites are occupied, saturation is achieved at a point.
59
What is Stereospecificity?
The binding sites for solutes on the transport protein are stereospecific.
60
What is competition?
Although the binding sites for transported solutes are quite specific, they may recognize, bind, and even transport chemically related solutes.
61
When does simple diffusion occur?
Simple diffusion occurs as a result of the random thermal motion of molecules.
62
What is net diffusion of the solution called?
Flux or flow (J); which depends on the following variables: size of the concentration gradient, partition coefficient, diffusion coefficient, thickness of the membrane, and surface areas available for diffusion.
63
What is the concentration gradient across the membrane?
It is the driving force for net diffusion.
64
T/F if the concentrations in the two solutions are equal, there is no driving force and no net diffusion.
True
65
What is the partition coefficient (K)?
Describes the solubility of a solute in oil relative to its solubility in water.
66
________ solutes tend to be soluble in oil and have high values for partition coefficient, whereas _____ solutes tend to be insoluble in oil and have low values for partition coefficient.
Nonpolar solutes; polar solutes
67
What is the diffusion coefficient?
It depends on such characteristic such as size of the solute molecule and the viscosity of the medium.
68
The diffusion coefficient correlates ______ with the molecular radius of the solute and the viscosity of the medium.
inversely
69
T/F small solute in nonviscious solutions have the largest diffusion coefficients and diffuse most readily; large solutes in viscous solutions have the smallest diffusion coefficients and diffuse least readily.
True
70
True/ False The thicker the cell membrane, the greater the distance the solute must diffuse and the lower the rate of diffusion
True
71
T/F the greater the surface area of membrane available, the higher the rate of diffusion.
True
72
What is permeability?
Permeability includes the partition coefficient, the diffusion coefficient, and the membrane thickness.
73
If the diffusing solute is an ion or an electrolyte what are the two additional consequences?
1. there is a potential difference across the membrane, that potential difference will alter the net rate of diffusion of a charged solute.
2. When a charged solute diffused down a conc. gradient, that diffusion can itself generate a potential difference across a membrane called a diffusion potential.
74
Facilitated Diffusion
Like simple diffusion, facilitated diffusion occurs down an electrochemical potential gradient; thus it requires no input of metabolic energy.
75
Facilitated Diffusion
Unlike simple diffusion, facilitated diffusion uses a membrane carrier and exhibits all the characteristics of carrier- mediate transport: saturation, stereospecificity, and competition.
76
Primary Active Transport
one or more solutes are moved against an electrochemical potential gradient (uphill) low-high, uses ATP
77
Example of Facilitated Diffusion
Transport of D- Glucose into skeletal muscle and adipose cells by the GLUT4 transporter.
78
Examples of Primary Active Transport
Na+-K+ ATPase (cell membranes) , Ca2+ ATPase (ER), H+-K+(Gastric Parietal Cells and renal intercalated cells)
79
Na+-K+ ATPase is present in the membrane of all cells. What does it pump?
It pumps Na+ from ICF to ECF and K+ from ECF to ICF. For every three Na+ ions pumped out of the cell, two K+ ions are pumped into the cell.
80
What is the function of the Ca2+- ATPase pump?
function is to extrude Ca2+ from the cell against an electrochemical gradient; one Ca2+ ion is extruded for each ATP hydrolyzed.
81
What does the H+-K+ ATPase pump do?
In the stomach, it pumps H+ from the ICF of the parietal cells into the lumen of the stomach, where it acidifies the gastric contents.
82
What is Secondary Active Transport?
Transport of two or more solutes is coupled. One of the solutes, usually Na+ moves down its electrochemical gradient (downhill) and the other solute moves against its electrochemical gradient (uphill). The downhill movement of Na+ provides energy for the uphill movement of the other solute. Thus metabolic energy, as ATP, is not used directly, but it is supplied indirectly in the Na+ conc. gradient across the cell membrane.
83
What are the two types of secondary active transport?
If the uphill solute moves in the same direction as Na+ it is called Cotransport, or symport. If the uphill solute moves in the opposite direction of Na+ its is called countertransport, antiport or exchange.
84
What is Cotransport?
A form of secondary active transport in which all solute are transported in the same direction across the cell membrane.
85
What is Countertransport?
Countertransport (antiport or exchange) is a form of secondary active transport in which solute move in opposite directions across the cell membrane.
86
What is Osmosis?
The flow of water across a semipermeable membrane because of differences in solute concentration. Conc. differences of impermeant solutes establish osmotic pressure differences, and this osmotic pressure difference causes water to flow by osmosis.
87
What is Osmolarity?
Conc. of osmotically active particles, expressed as osmoles per lite or milliosmoles per liter.
88
If two solutions have the same calculated osmolarity, they are called______.
Isosmotic
89
If two solutions have different calculated osmolarities, the solution with the higher osmolarity is called______.
Hyperosmotic
90
If two solutions have different calculated osmolarities the solution with the higher osmolarity is called hyperosmotic and the solution with the lower osmolarity is called_______.
Hyposmotic.
91
______osmolality is similar to osmolarity, except that is is the conc. of osmotically active particles, expressed as osmoles (or milliosmoles) per kilogram of water.
Osmolality.
92
When two solutions separated by a semipermeable membrane have the same effective osmotic pressure they are _____.
Isotonic; no water will flow between them because there is no effective osmotic pressure difference across the membrane.
93
When two solutions have different effective osmotic pressures, the solution with the lower effective osmotic pressure is _______.
Hypotonic.
94
When two solutions have different effective osmotic pressures, the solution with the lower effective osmotic pressure is hypotonic, and the solution with the higher effective osmotic pressure is ______.
Hypertonic.
95
What are Ion channels?
Ion channels are integral, membrane- spanning proteins, when open, permit the passage of certain ions.
96
Ion channels are ______ and allow ions with specific characteristics to move through them.
Selective; this selectivity is based on both the size of the channel and the charges lining it.
97
Ion channels are controlled by _____.
Gates
98
What are Voltage- Gated Channels?
Gates that are controlled by changes in membrane potential.
99
What are second messenger-- gated channels?
gates that are controlled by changes in levels of intracellular signaling molecules.
100
What are Ligand- gated channels?
Gates that are controlled by hormones and neurotransmitters.
101
What is a Diffusion Potential?
the potential difference generated across a membrane when a charged solute (an ion) diffused down its concentration gradient. Therefore a diffusion potential is caused by the diffusion of ions.
102
The ______ of a diffusion potential, measured in millivolts, (mV) depends on the size of the conc gradient, where the conc. gradient is the driving force.
Magnitude
103
The _____ of the diffusion potential depends on the charge of the diffusing ion.
sign
104
What is the Equilibrium Potential?
the diffusion potential that exactly balances or opposes the tendency for diffusion down the conc. difference.
105
At _____ ______ the chemical and electrical driving forces acting on an ion are equal and opposite and no further net diffusion occurs.
Electrochemical Equilibrium
106
What is the Nernst Equation
Used to calculate the equilibrium potential for an ion at a given conc difference across a membrane, assuming that the membrane is permeable to that ion.
