A&p I - Exam 1

Front 1

Cell (protoplasm) Components

Back 1

- Nucleus - surrounded by nuclear membrane
- Cytoplasm - surrounded by cell membrane (or plasma membrane)

Front 2

Chemical components of Cell

Back 2

Water - 70-85% of cell mass
Proteins - 10-20% of cell mass
Electrolytes
Lipids
Carbohydrates

Front 3

Proteins

Back 3

- Structural - polymeric microfilaments; comprise cytoskeleton
- Functional - enzymes; found in cytoplasm as well as cell membrane and organelles

Front 4

Electrolytes

Back 4

- Dissolved in cell water
- Cations: K, Mg, Na
- Anions: phosphate, Cl, HCO3
- Important in determining cell membrane electrical potential

Front 5

Lipids

Back 5

Membrane lipid: phospholipids, cholesterol
Triglycerides: neutral fat; energy storage, 95% of adipocyte cell mass

Front 6

Glycocalyx

Back 6

- Cell membrane carbohydrates
- "Coat of the cell"
- Functions: cell-cell and cell-interstitium interactions, hormone binding, immune recognition

Front 7

Glycoprotein and Glycolipid

Back 7

- Carbohydrate molecules attached to membrane proteins and lipids;
- Protrude from outer surface of cell membrane

Front 8

Proteoglycans

Back 8

Loosely attached to outer surface of the cell

Front 9

Glycogen

Back 9

Energy storage; found primarily in liver and muscle cells

Front 10

Cell Membrane Composition

Back 10

- Elastic, 7.5-10 nanometers wide
- 55% proteins, 25% phospholipids

Front 11

Cell Membrane Structure

Back 11

- Lipid bilayer
- Membrane proteins

Front 12

Lipid Bilayer

Back 12

- Phospholipids
- Fluid, not solid
- Poorly permeable to hydrophilic: ions, glucose, amino acids
- Relatively permeable to lipophilic: gases (O2, CO2, volatile anesthetics), alcohol, lipophilic drugs

Front 13

Membrane Proteins

Back 13

- float in a sea of lipid
- Most are glycoproteins
- Integral and Peripheral proteins

Front 14

Integral Proteins

Back 14

- Pass all the way through the membrane
- Some provide pores for ions to move across membrane
- Some act as carriers, shuttle glucose & amino acids across membrane
- Some function as receptors that bind specific ligands (hormones, neurotransmitters, drugs), and trigger a cellular response

Front 15

Peripheral Proteins

Back 15

- Occur on inner surface of cell membrane
- Function as enzymes

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Cytoplasm

Back 16

- Water w/ dissolved and suspended substances (cytosol)
- Organelles
- Cytoskeleton

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Organelles

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- Membrane-bound structures
-- ER
-- Golgi Apparatus
-- Lysosomes
-- Mitochondria

Front 18

Edoplasmic Reticulum (ER)

Back 18

- Network of interconnected tubules surrounded by lipid bilayer membranes
- Fluid space inside tubules known as Matrix
-- Rough and Smooth ER

Front 19

Rough ER

Back 19

- Ribosomes attached to outer surface, synthesize proteins
- Proteins transported into matrix, then Glycosylated to form Glycoproteins

Front 20

Smooth ER

Back 20

- Contiguous with Rough ER
- Synthesize lipid substances: phospholipids and cholesterol
- In liver, smooth ER responsible for biotransformation of many drugs

Front 21

Transport Vesicles

Back 21

- Constantly break off from smooth ER
- Contain proteins and other substances
- Fuse with Golgi apparatus

Front 22

Golgi Apparatus

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- Tubular stacks
- Further processes substances synthesized in ER
- In secretory cells, form Secretory Vesicles that contain peptides and proteins to be secreted by cell (exocytosis)
- Form lysosomes

Front 23

Lysosomes

Back 23

- Intracellular digestive system
- Surrounded by a lipid bilayer
- Attach to pinocytic or phagocytic vesicles that enter cell
- Contain hydrolases and bactericidal enzymes
- Tissue trauma and other events can destabalize lysomal membranes and cause release of hydrolases -> autolysis and tissue repair

Front 24

Mitochondria

Back 24

- Have DNA and can replicate
- Generate energy for cell by producing 95% of cell ATP

Front 25

ATP

Back 25

- Adenosine triphosphate
- Contain high-energy phosphate ester bonds
- Breaking a bond with ATPase enzymes yields about 12 kcal / mole of ATP hydrolyzed
- Synthesized in the mitochondria by the process of oxidative phosphorylation
- Used for:
-- membrane transport (ions)
-- synthesis of chemical compounds (proteins)
-- mechanical work (muscle contraction)

Front 26

Oxidative Phosphorylation

Back 26

- H is oxidized to H2O
- ADP + Pi --> ATP
(see p. 7 of notes)

Front 27

Cytoskeleton

Back 27

- Microfilaments
- Microtubules

Front 28

Microfilaments

Back 28

- Formed by polymerized fibrillar proteins synthesized at ribosomes (actin, myosin)

Front 29

Microtubules

Back 29

- Microfilaments comprised of tubulin molecules organized into hollow structures
- Provide cytoskeleton of cell
- Play roll in intracellular transport

Front 30

Nucleus

Back 30

- Control protein synthesis and cell reproduction
- Codes for protein synthesis are located on genes (regions of DNA), which are located in the chromatin material (chromosomes) of the nucleus
- Nucleolus - contains RNA and proteins

Front 31

Total Body Water

Back 31

- Approx. 60% of body weight
- 70 kg person = 42 L
- Influenced by age, gender, and % body fat

Front 32

Body Fluid Compartments

Back 32

- Intracellular fluid
- Extracellular fluid

Front 33

Intracellular Fluid

Back 33

- 2/3 of total body water
- about 28 L in a 70 kg person

Front 34

Extracellular Fluid

Back 34

- 1/3 of total body water
- about 14 L in a 70 kg person
- Composed of:
-- interstitial fluid
-- plasma water

Front 35

Interstitial Fluid

Back 35

- Lies in the interstitial spaces between cells
- Nearly all is trapped as a gel by macromolecule fibers
- About 80% of ECF
- About 11 L in a 70 kg person

Front 36

Plasma Water

Back 36

- About 20% of ECF
- About 3 L in a 70 kg person
(blood volume is about 5 L)

Front 37

Interstitium
(Interstitial Compartment)

Back 37

- Connective tissue system
- Composed of collagen fibers imbedded in a meshwork of proteoglycans
- Collagen fibers are primarily Type I and III
- Very strong; provide most of structural integrity of tissues

Front 38

Connective Tissue Diseases

Back 38

- Rheumatoid disorders
- Collagen vascular diseases: SLE, scleroderma, vasculitis syndromes
- Granulomatous diseases: Wegener’s granulomatosis, sarcoidosis
- Marfan’s syndrome -- structural weakness in Type I collagen fibers
- Ehlers-Danlos syndrome -- group of collagen synthesis disorders

Front 39

Indicator Dilution Technique

Back 39

Volume = Amount of Indicator Injected / Concentration of Indicator in Sampled Fluid

Front 40

Measure Plasma Volume

Back 40

- Indicator confined to vascular space
- Radiolabelled (125 I) albumin
- Evan's Blue Dye -- binds to serum albumin

Front 41

Measure Extracellular Fluid Volume

Back 41

- Indicator ideally distributes uniformly throughout extracellular fluid
- 22 Na+ or inulin
- Na+ enters cells to some degree, so slightly overestimates true ECF volume
- Inulin is slightly restricted from some extracellular regions, so slightly underestimates true ECF volume

Front 42

Measure Total Body Water

Back 42

- Indicator uniformly distributes throughout all compartments - crosses cell membranes
- Radioactive water (2H or 3H) or antipyrine
- Equilibration requires several hours
- Must correct for clearance (urine, metabolism)

Front 43

Calculation of Intracellular and Interstitial Fluid Volumes

Back 43

- Intracellular
-- (Total Body Water - ECF Volume)
- Interstitial
-- (ECF Volume - Plasma Volume)

Front 44

Extracellular Composition

Back 44

- Cations: Na+, K+, Ca++
- Anions: Cl-, HCO3-, proteins, phosphate
- plasma has higher protein concentration than interstitial
- "internal environment" of the body
- volume and composition of ECF are precisely regulated

Front 45

Intracellular Composition

Back 45

- Cations: K+, Mg++, Na+
- Anions: phosphate, proteins, HCO3-

Front 46

Law of Electroneutrality

Back 46

In each major fluid compartment, the total number of positive charges = the total number of negative charges

Front 47

Osmolarity

Back 47

Number of osmoles (or milliosmoles) per liter of solution

Front 48

Osmolality

Back 48

Number of osmoles (or milliosmoles) per kilogram of water

Front 49

One Osmole =

Back 49

One Mole (Avogadro’s number) of osmotically active solute particles in solution

Front 50

Osmolality / Osmolarity

Back 50

- Independent of the size and charge of the solute particles (at least in dilute solutions)
- Only # of particles matter

Front 51

Osmotic Pressure (π)

Back 51

π = CRT (van’t Hoff’s law)
- C = total solute concentration
- R = universal gas constant
- T = temp (Kelvin)
At body temp: RT = 19.3

Front 52

Diffusion (Passive Transport)

Back 52

- Random movement of particles due to their kinetic energy
- Rate of diffusion depends on: particle size, properties of the medium, temperature
- Diffuse from high concentration to low concentration due to increased frequency of collisions

Front 53

Net Flux

Back 53

Net Flux = P x A x ΔC
- P = permeability coefficient (cm/sec)
- A = area of membrane available for diffusion (cm2)
- ΔC = concentration difference across the membrane (mol/cm3; mmol/cm3)

Front 54

Permeability

Back 54

- directly related to solubility
- inversely related to size
- inversely related to membrane thickness
- directly related to temperature

Front 55

Protein Channel Diffusion

Back 55

- route of transport for ions

Front 56

Leak Channels

Back 56

- always open
- more permeable to K than Na
(more K in cell) (more Na outside of cell)

Front 57

Na Selective Channels

Back 57

- Lined with negatively charged amino acids
- Gates on inner and outer surfaces

Front 58

K Selective Channels

Back 58

- Lined with carbonyl groups
- Gate on inner surface only

Front 59

Gating

Back 59

- Way of controlling ion channel permeability
-- Voltage gating - channel opens or closes due to change in membrane potential
-- Chemical gating - binding of a specific ligand to a channel causes it to open

Front 60

Facilitated Diffusion

Back 60

- Carrier-mediated diffusion for substances that are too large (glucose and amino acids)
- Carriers bind to and transport substances across membrane
- Max rate of transport due to limited # of integral proteins

Front 61

Voltage (ΔV)

Back 61

- Developed due to diffusion of ions across a selectively permeable membrane due to a concentration difference
- Affects the movement of any ion in response to ΔC

Front 62

Nernst Equilibrium Potential

Back 62

- The potential difference across a membrane when diffusion of an ion in response to a ΔC is balanced exactly by movement in the opposite direction in response to ΔV

E(ion) = (± 61 mV) log C1/C2

- C1 = concentration inside cell
- C2 = concentration outside cell
- E = polarity is cell interior w/ respect to cell exterior
- Use + 61 mV for negative ions
- Use - 61 mV for positive ions

Front 63

Active Transport

Back 63

- Movement "uphill" against an electrochemical gradient
- Requires energy (ATP)

Front 64

Na-K Pump

Back 64

- Present in all cell membranes
- Responsible for maintaining asymmetric concentrations of Na+ and K+ between the intracellular and extracellular fluids

Front 65

Characteristics of Na-K Pump

Back 65

- 3 Na binding sites (in -> out)
- 2 K binding sites (out -> in)
- Helps establish negative cell membrane potential

Front 66

Calcium Pump

Back 66

- Ca-i is much less inside cell than out
- Cell membrane pumps actively remove
- Mitochondria and SR use Ca

Front 67

Secondary Active Transport

Back 67

- Does NOT require ATP
- "Uphill" transport of glucose & amino acids are coupled with "downhill" transport of Na from cell exterior to interior
- Called "active" because of coupling with Na-K pump transport

Front 68

Characteristics of Active Transport

Back 68

- V-max for active transport
- Energy expended in transporting against concentration gradient is proportional to the degree to which the substance is concentrated

Front 69

Osmosis

Back 69

Diffusion of water across selectively permeable membrane in response to difference in osmotic pressure across membrane

Front 70

Jv ∝ Lp • A • Δπ

Back 70

Jv = net flux
Lp = water permeability
A = area of membrane
Δπ = difference in osmotic pressure

π = CRT
-- C = total solute concentration
-- R = universal gas constant
-- T = temp (Kelvin)
----At body temp: RT = 19.3

Front 71

Osmotic Pressure ∝ Osmolality

Back 71

- Osmolality is determined by number of particles / unit volume, NOT mass of particles
- Osmotic Pressure = force that must be applied to one side of membrane to stop osmosis

Front 72

Water Concentration

Back 72

- Inversely related to solution osmolality
- water moves passively down concentration gradient
- moves from lower osmolality to higher osmolality
(it wants to dilute a more concentrated solution)

Front 73

Water Movement between Body Fluid Compartments

Back 73

- Most cell and capillary membranes have very high water permeability
- Water readily moves across membranes by osmosis in response to difference in osmolality

- Total solute concentration of each compartment is approx 300 mOsmol/kg H2O (or 300 mOsmol/L)
- Corrected osmolality of each body fluid compartment is approx 280 mosmol/kg H2O

- In steady state, intracellular and interstitial osmolalities are identical
- Plasma osmolality is slightly greater than interstitial osmolality due to protein

Front 74

Osmotic Equilibrium across Cell Membrane

Back 74

- Increase or decrease osmolality of extracellular fluid cause rapid movement of water between interstitial and intracellular compartments

Front 75

Isotonic

Back 75

Causes no Δ in cell volume

Front 76

Hypotonic

Back 76

Lowers intracellular osmolarity, causes water to enter cell

Front 77

Hypertonic

Back 77

Raises intracellular osmolarity, causes water to leave cell

Front 78

Isosmotic

Back 78

Same osmolarity as intracellular (280 mOsm/L)

Front 79

Hypo-osmotic

Back 79

Osmolality less than intracellular (200 mOsm/L)

Front 80

Hyperosmotic

Back 80

Osmolality is more than intracellular (360 mOsm/L)

Front 81

Electrical Potential

Back 81

- Exist across the membranes of all cells of the body
- Cell interior is negatively charged with respect to the exterior
- Some cells, especially nerve and muscle cells, undergo changes in membrane potential that are critical to their normal function

Front 82

Cell Membrane Potential

Back 82

E-m = E-diff + E-elec

- the resting E-m (large nerves, skeletal muscle) is normally about -90mV

Front 83

Diffusion Potential (E-diff)

Back 83

- K+ is continually diffusing out of the cell in response to a ΔC; this K+ "leak" occurs through leak channel proteins in the membrane
- Na+ is continually diffusing into the cell in response to a ΔC and ΔV; this Na+ "leak" occurs through leak channel proteins in the membrane
- Differential permeability of the cell membrane to Na+ and K+ gives rise to a E-diff of approximately – 86 mV

- Cell is more permeable to K than Na
P-K+ = 100 x P-Na+

Front 84

Electrogenic Potential (P-elec)

Back 84

- Cell membrane transports 3 Na+ out for every 2 K+ pumped into cell
- positive charge accumulates outside cell membrane
- separation of charge by sodium-potassium pump contributes approx – 4 mV to the E-m

E-m = -86 mV + -4 mV = -90 mV

Front 85

Total Charge Separation

Back 85

- At an Em of –90mV, total amount of charge separation across cell membrane only 10^-12 mole
- Membrane behaves as biological capacitor
- Importantly, Law of Electroneutrality not violated for intracellular and interstitial fluids, because amount of charge separation is so small