Cell & Muscle Physiology Flashcards
(135 cards)
1
Q
Basic unit of human body/life
A
Cell
2
Q
Most abundant type of cell in body
A
RBCs
3
Q
of neurons
A
100 billion
4
Q
Major hallmarks of cancer
A
• Loss of cell-to-cell adhesion
• Anchorage independent growth
5
Q
Guardian of the cell
A
Cell membrane
6
Q
Water in body is 60%. _____ is ICF and _____ ECF
A
2/3 ICF
1/3 ECF
7
Q
Loose carbohydrate coat of cell surface
A
Glycocalyx
8
Q
Components of Lipid bilayer (fluid-mosaic model)
A
Head is glycerol
Tail is hydrophobic
55% proteins
25% Phospholipids
13% cholesterol
4% other lipids (glycolipids)
3% carbohydrates
9
Q
Outer leaflet of phospholipids
A
Phosphatidylcholine
Sphingomyelin
10
Q
Inner leaflet of phospholipids
A
Phosphatidylethanolamine
Phosphatidylserine
Phosphatidylinositol
11
Q
1 component of cell membrane
A
Proteins
• Integral
• Peripheral
12
Q
Most important component of cell membrane
A
Cholesterol
(membrane fluidity and permeability —> lipid soluble substances can go through cell membrane easily)
13
Q
Component of cell membrane that confers antigenicity
A
Glycolipids
14
Q
Major lipoprotein source of cholesterol
A
LDL
15
Q
Na vs. K: At rest, the membrane is more permeable to..
A
K
16
Q
Factors that determine permeability of membrane
A
• Temperature (inc. temp = inc. permeability)
• Type of solute (inc. lipid solubility = inc. permeability
• Level of cell hydration (inc. concentration difference —> affect diffusion and osmosis = inc. permeability)
17
Q
PROTEIN IN CELL MEMBRANE:
Integral vs. Peripheral
• Has tight attachments
• Uses hydrophobic interactions
• Spans entire cell membrane (go through 2 bilayers)
• e.g. aquaporins, ion channels, solute carriers, ATP-dependent transporters
A
Integral proteins
18
Q
PROTEIN IN CELL MEMBRANE:
Integral vs. Peripheral
• Has loose attachment
• Uses electrostatic interaction
• either in inner or outer leaflet (only 1 bilayer)
A
Peripheral proteins
19
Q
MOVEMENT OF SUBSTANCES ACROSS THE CELL MEMBRANE:
Water
A
Osmosis (via aquaporins)
20
Q
MOVEMENT OF SUBSTANCES ACROSS THE CELL MEMBRANE:
Lipid-soluble substances
A
Simple diffusion (high concentration to low concentration)
21
Q
MOVEMENT OF SUBSTANCES ACROSS THE CELL MEMBRANE:
Water-soluble substances
A
Carrier-mediated transport
22
Q
IONS:
Main cation in ECF
Main determinant of osmolarity
A
Sodium (Na)
23
Q
IONS:
Main cation in ICF
A
Potassium (K)
24
Q
IONS:
Main anion in ECF
Main ion in GI tract
Associated with Cystic fibrosis (CFTR gene, sweating) & cholera
A
Chloride (Cl)
25
IONS:
Utilized by all types of muscles (power for muscle contraction)
Calcium (Ca)
26
IONS:
Only electrolyte mainly reabsorbed in Thick Ascending Limb of Loop of Henle (TAL of LH), majority are reabsorbed in PCT
Magnesium (Mg)
27
MOVEMENT OF SUBSTANCES ACROSS THE CELL MEMBRANE:
Amino acids - Luminal membrane
Na-amino acid symport
28
MOVEMENT OF SUBSTANCES ACROSS THE CELL MEMBRANE:
Amino acids - Basolateral membrane
Facilitated diffusion
29
RATE OF DIFFUSION/TRANSPORT
Facilitated vs. Simple
Which is faster when there is dec. solute concentration?
Facilitated diffusion
(Has “car” which is the carrier mediated protein)
30
RATE OF DIFFUSION/TRANSPORT
Facilitated vs. Simple
Which is faster when there is inc. solute concentration?
Simple diffusion
(Has no saturation —> no Tmax —> rate of transport does not plateau; Rate of transport only depends on concentration difference)
31
INTERCELLULAR STRUCTURES BETWEEN CELL MEMBRANE
• Disk shaped
• For tight intercellular adhesion (like staple wires)
• e.g epithelium
Macula adherens (desmosomes)
32
Formula for Simple Diffusion
J = PA (C1-C2)
J = flux (mmol/sec)
P = permeability (cm/sec)
A = area (cm2)
C1 = higher concentration 1 (mmol/L)
C1 = lower concentration 2 (mmol/L)
33
Permeability is increased by:
Increased oil/water partition coefficient (inc. lipid sol)
Decreased radius of solute
Decreased membrane thickness
34
Where is GLUT-1 found?
Blood brain barrier
RBCs
Placenta
Cornea
35
Where is GLUT-2 found?
Liver
Pancreas (B islet cells)
Basement membrane of SI
Kidney
36
Where is GLUT-3 found?
Neurons
Placenta
37
Where is GLUT-4 found?
Muscle
Adipose tissue
38
Where is GLUT-5 found?
For fructose transport from SI limen to SI cells
Speematocytes (fructose is energy source for sperm motility)
39
The only insulin dependent glucose transporter
GLUT-4
40
Inhibitor of Na-K-ATPase pump
Digoxin
41
Ca-ATPase pump in Sarcoplasmic reticulum that pumps Ca back into SR
SERCA
42
Main electrolyte that maintains the cell gradient
Sodium (Na)
43
Formula of osmolarity
Osmolarity
= concentration x # of dissociable particles mOsm/L
= mmol/L x # of particles/mol
44
Driving force of osmolarity
Osmotic pressure
45
Osmotic pressure is calculated using?
Van’t Hoff Law
π = g x C x RT
π = osmotic pressure (atm or mmHg)
g = # of particles per mole in sol (Osm/mol)
C = Concentration (mmol/L)
R = Gas constant (0.082 L - atm/mol - K)
T = Absolute temp (K)
46
Effective osmotic pressure formula
Osmotic pressure x reflection coefficient
47
Osmotic pressure exerted by proteins
Oncotic pressure/colloid osmotic pressure
48
Reflection coefficient formula
Amount returned/amount sent
(A number from 0 to 1, describes ease of membrane permeation of solute)
49
Ineffective osmole with a reflective coefficient of 0 (complete solute penetration)
Urea
50
Effective osmole with a reflective coefficient of 1 (no solute penetration)
Albumin
51
Potential difference generated across a membrane because of concentration difference of ion
Diffusion potential
52
Diffusion potential that exactly balances (opposes) the tendency for diffusion caused by concentration difference
Equilibrium potential/Nernst potential
53
Resting membrane potential (-70 mv) is caused by
Nernst potential for Na and K
K-leak channels
Na-K-ATPase pump (contributes -4 mv)
54
Excitable cells that exhibit AP
Neurons
Muscles
55
Characteristics of a true action potential
SPA
Stereotypical size and shape
Propagating
All or none
56
At the RESTING STATE, what happens to the Na-activation (m), Na-inactivation (h), and K gates?
Na-activation gate - closed
Na-inactivation gate - open
K-gate - closed
57
During DEPOLARIZATION, what happens to the Na-activation (m), Na-inactivation (h), and K gates?
Na-activation gate - open
Na-inactivation gate - open
K-gate - closed
58
During REPOLARIZATION, what happens to the Na-activation (m), Na-inactivation (h), and K gates?
Na-activation gate - open
Na-inactivation gate - closed
K-gate - open
59
At UNDERSHOOT, what happens to the Na-activation (m), Na-inactivation (h), and K gates?
Na-activation gate - closed
Na-inactivation gate - closed
K-gate - open
60
Basis for Absolute refractory period
Closed Na-inactivation gates
61
Basis for relative refractory period
Prolonged opening of K-channels
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AP Conduction Velocity is increased by
Rapid Na Channel gating - rapid AP upstroke
Wide axons - lower resistance - faster
Myelination - insulation
Saltatory conduction - AP jump from node to node, reducing need for slower active regeneration steps
63
SUPPORTING CELLS OF NERVOUS SYSTEM
Tissue macrophage that acts as scavenger cells (remove debris)
Microglia
64
SUPPORTING CELLS OF NERVOUS SYSTEM
Macroglia that form myelin in the CNS
Oligodendrocytes
65
SUPPORTING CELLS OF NERVOUS SYSTEM
Macroglia that form myelin in the PNS
Schwann cells
66
SUPPORTING CELLS OF NERVOUS SYSTEM
Helps in regeneration and remyelinatiin in PNS
Schwann cells
67
SUPPORTING CELLS OF NERVOUS SYSTEM
Macroglia that send processes that envelope synapses and surface of nerve cells
Helps form the BBB
Astrocytes
• In white matter - fibrous
• In gray matter - protoplasmic (maintains appropriate concentration of iins and NTs by taking up K, glutamate, and GABA)
68
Mechanism for release of NTs to synapse
Exocytosis (non-carrier mediated transport)
69
Autoimmune dse wherein antibodies against voltage gated Ca channels are produced, preventing Acetylcholine from being released to NMJ
Lambert-Eaton Myasthenic Syndrome
70
Autoimmune dse directed at components of myelin sheath
Multiple sclerosis
71
What is found at fhe brain MRI and CSF analysis of MS patients?
Oligoclonal bodies
72
MS is associated with this gene
HLA-DR2
73
Clinical presentation of MS
• Distinct episodes of neurological deficits that are separated in time (due to patchy white matter lesions separated in space)
• paraparesis
• paresthesia
• optic neuritis (pain in eye movements, loss of color perception, central scotoma, BOV)
If transient (lasts weeks or months): Relapsing-remitting MS
If no remission: Primary progressive MS
74
Neurotransmitter that opens Na-K pumo that depolarizes the muscle endplate to value halfway between Na-K equilibrium potentials
Dec in Huntington and Alzheimer dementia
Acetylcholine (ACH)
75
Primary neurotransmitter of postganglionic sympathetic neurons
Norepinephrine
76
Plant used for depression but contraindicated in pregnant
St. John’s Wort
77
Nitric Oxide is a ___________ NT and vaso-___________
78
From tryptophan: melanin vs. melatonin
Melatonin
79
From tyrosine: melanin vs. melatonin
Melanin
80
Main inhibitory NT of spinal cord
Glycine
81
Main inhibitory NT of brain
GABA
82
Main exhitatory NT of brain
Glutamate
83
NT Involved in pain perception
Opiod peptide
84
NT for fast pain
Glutamate
85
NT for slow pain
Substance P
86
NT that Activates NMDA receptors
Glutamate
87
Affinity of opiod peptides:
Endorphins
Mu
88
Affinity of opiod peptides:
Enkephalins
Kappa
89
Affinity of opiod peptides:
Dynorphin
Delta
90
Opioid receptor that is the site of action of morphine
Mu
91
Type of skeletal muscle that detects changes in muscle length
Intrafusal (5%)
92
Type of skeletal muscle that causes voluntary muscle contraction
Extrafusal (95%)
93
Characteristics of Extrafusal Type I fibers
• Slow twitch
• Red
• Oxidative
• Numerous mitochondria
• e.g: Postural muscles of the back
• For endurance
94
Characteristics of Extrafusal Type II fibers
• Fast twitch
• White
• Anaerobic glycolysis (non-oxidative)
• Few mitochondria
• e.g: EOM
• For power (wt, resistance, sprint)
95
Innervations of Intrafusal and extrafusal, respectively
Intrafusal - gamma motor neurons
Extrafusal - alpha motor neurons
96
Composition of thick filaments
• Myosin - cross bridges of sarcomere
• 2 pairs of light chains, 1 pair of heavy chains
• 2 heads, 1 tail
97
Composition of thin filaments
• Actin
• Tropomyosin - relaxing protein that covers actin binding sites at rest
• Troponin
* Troponin T - attaches troponin complex to tropomyosin
* Troponin I - inhibits actin-myosin binding
* Troponin C - calcium-binding protein
98
Type of muscle fiber not used by a sedentary person
Type II muscle fiber (fast twitch, white fibers)
99
Majority of muscle weight comes from?
Myosin
100
PARTS OF A SARCOMERE:
Borders
Z-lines
101
PARTS OF A SARCOMERE:
Midline
M line
102
PARTS OF A SARCOMERE:
Entire length of myosin
A band
103
PARTS OF A SARCOMERE:
Purely myosin, no actin interspersed
H band
104
PARTS OF A SARCOMERE:
No myosin heads
Bare zone
105
PARTS OF A SARCOMERE:
Purely actin, no myosin interspersed
I band
106
PARTS OF A SARCOMERE:
1. Invaginations of sarcolemma
Spreads action potential throughout muscles. 2. Contains ____________
1. Transverse (T-tubules)
2. Dihydropyridine receptors (DHPR)
107
PARTS OF A SARCOMERE:
1. Located in T-tubulesand voltage sensitive. 2. It activates____________
1. Dihydropyridine receptors
2. Ryanodine receptors
108
PARTS OF A SARCOMERE:
1. Contains Ca needed for muscle contraction
2. Amoubt of released Ca depends on ____________
1. Sarcoplasmic reticulum (SR)
2. Stored calcium
109
1. Ca release channel in SR
2. It is activated by _________
1. Ryanodine
2. Dihydropyridine receptors (DHPR)
110
PARTS OF A SARCOMERE:
PROTEIN that stores Ca in the SR
Calsequestrin
111
PARTS OF A SARCOMERE:
Pumps Ca from ICF to SR
Sarcoplasmic reticulum Calcium ATPase pump (SERCA)
112
PARTS OF A SARCOMERE:
Binds myosin to Z-lines, and binds Z-lines to M-lines
Deficiencies cause numerous dystrophy and scleroderma
Titin
113
Deficient protein in Duchenne muscular dystrophy
Dystrophin
114
PARTS OF A SARCOMERE:
Stabilizes sarcolemma and prevents contraction-induced rupture
Dystrophin
115
PARTS OF A SARCOMERE:
Binds actin to Z lines
Actinin, CapZ protein
116
PARTS OF A SARCOMERE:
Binds Z lines to sarcolemma
Desmin
117
PARTS OF A SARCOMERE:
Acts a molecular rulers that sets length of actin
Nebulin
118
Initiates AP in skeletal muscle fiber
Sodium (Na)
119
DRUGS THAT AFFECT NMJ:
Blocks release of acetylcholine from presynaptic terminals
Botulinum toxin
120
DRUGS THAT AFFECT NMJ:
Competes with Ach for receptors on motor-endplate
Curare
121
DRUGS THAT AFFECT NMJ:
Inhibits acetylcholinesterase
Neostigmine
122
DRUGS THAT AFFECT NMJ:
Blocks reuptake of choline into presynaptic terminal
Hemicholinium
123
Dx test for Myasthenia gravis
Edrophonium (AchE inhibitor)/Tensilon test
124
Myasthenia gravis mimics this type of poisoning
Malathion poisoning
125
INTERCELLULAR STRUCTURES BETWEEN CELL MEMBRANE
• Ring shaped
• Increases surface area for contact
• e.g epithelial and endothelia cells, intercalated disks of cardiac muscles
Zonula Adherens
126
INTERCELLULAR STRUCTURES BETWEEN CELL MEMBRANE
• Barrier to movement of proteins across membranes
• divides cell into apical and basolateral side
• e.g epithelium
Zonula occludens (Tight junctions)
127
INTERCELLULAR STRUCTURES BETWEEN CELL MEMBRANE
• Bridge for sharing small molecules between cells
• For rapid intercellular communication (contract as one/SYNCITIUM!)
• e.g cardiac and unitary smooth muscles
Gap junctions
128
INTERCELLULAR STRUCTURES BETWEEN CELL MEMBRANE
• Attach cell membrane to basement membrane
• e.g. stratum basale attaches to basement membrane using _____
Hemidesmosomes (only 1 side)
129
TYPE OF TIGHT JUNCTIONS:
Found in PCT and Jejunum
Leaky TJ
130
TYPE OF TIGHT JUNCTIONS:
Found in collecting duct, terminal colon, blood brain barrier
Tight TJ
131
TYPES OF TRANSPORT FOR ZONULA OCCLUDENS/TIGHT JUNCTION:
Movement across apical and basolateral sides
Transcellular transport
132
TYPES OF TRANSPORT FOR ZONULA OCCLUDENS/TIGHT JUNCTION:
Movement through tight junctions
Paracellular transport
133
Integral proteins inside tight junctions
Claudin
134
Functional unit of gap junction
(Hexagonal in shape)
Connexon
135
Subunit of connexon
Connexin
