Exam 2-Ch 4, 9, 10 Flashcards
1
Q
Excitable tissue
A
Specialized use; nerve & muscle
2
Q
Polarization
A
Any time potential is not 0 mV; at rest, typical -70 mV
3
Q
Depolarization
A
Inside less negative than at rest - action potential
4
Q
Repolarization
A
Returns to resting
5
Q
Hyperpolarization
A
Inside more negative than at rest
6
Q
Electrical Triggering Events
A
Change in electrical field; Interaction of chemical messenger w/ receptors; Stimulus; Change in potential
7
Q
Leak channels
A
Open always
8
Q
Gated channels
A
Open/close; Voltage, Chemical, Mechanical, Thermal
9
Q
Voltage-gated
A
Change in membrane potential
10
Q
Chemically-gated
A
Change in shape due to binding EC chemical messenger
11
Q
Mechanically-gated
A
Respond to stretching or mechanical deformation
12
Q
Thermally-gated
A
Respond to change in temp
13
Q
Electrical Signal Types
A
Graded potentials, Action potentials
14
Q
Graded Potentials
A
Local change in membrane potential; vary in strength; Triggering event cause gated ion channels to open in specialized region of membrane (stronger, more open; longer, longer potential); Short distance; Current lost through leak channels, gradual decrease in strength
15
Q
Current
A
Flow of electrical charges; direction dependent on positive charges
16
Q
Resistance
A
Hindrance to electrical charge movement; Greater difference in potential or lower resistance, greater current flow; Low-conductors, High-lipids
17
Q
Action Potentials
A
Brief, rapid, large change in membrane potential; Travels long distance; Initiated by gated potential; threshold -50 mV, peak 30-40 mV
18
Q
Neuron
A
Cell body, dendrites, axons
19
Q
Dendrites
A
Contain protein receptors bind to chemical messengers from other neurons-input zone; graded potentials generated
20
Q
Axons
A
Single extension, carries AP away from cell body-output zone
21
Q
Axon hillock
A
Triggers AP conducted along axon to terminals
22
Q
Axon terminals
A
Release chemical messengers influence other cells
23
Q
Myelin
A
Lipids cover axon as insulator, prevents current leakage
24
Q
Nodes of Ranier
A
Between myelin, AP jumps from node to node-faster (voltage-gated Na+ channels)
25
Innervation
Neuron terminates on muscle to contract, gland to secrete, or other neuron to convey electrical message
26
Synapse
Junction between two neurons-electrical or chemical
27
Electrical Synapse
Gap junctions, ions flow directly between
28
Chemical Synapse
Majority; axon terminal (presynaptic)-neurotransmitters; space between synaptic cleft-close but not touching
29
Neurotransmitter
AP along axon pre-synaptic, triggers opening of voltage-gated Ca+2 channels, released by exocytosis, bind to post-synaptic receptors, chemically-gated channels open, one direction
30
Excitatory Synapse
Increase perm. Na+ and K+, Na+ electrochemical in > K+ concentration gradient out; Net-small depolarization
31
Inhibitory Synapse
Increased perm. K+ or Cl-; Net-hyperpolarization
32
SSRIs
Blocks reuptake serotonin into pre-synaptic, prolongs action neurotransmitter, used to treat depression
33
Cell-to-cell Communication
Direct-physical contact; Indirect (most common)-extracellular chemical messengers, neurotransmitters, paracrines, hormones, neurohormones, act on target cell
34
Paracrine
Local, diffusion short distances, ie histamine
35
Hormones
Long range chemical messengers secreted in blood by endocrine glands
36
Neurohormones
Hormones released into blood by neurosecretory neurons, ie Vasopressin aka ADH
37
Endocrinology
Study of homeostatic chemical adjustments and other activities accomplished by hormones; hydrophilic-peptides, amines, thyroid, dissolve in plasma; hydrophobic-steroids, thyroid, carried by plasma proteins (albumin), only small, unbound, freely dissolved portion biologically active
38
Atrioventricular (AV) Valves
Between atria and ventricle; Tricuspid-right, Mitral-left; Diastole
39
Diastole
Blood flows through valve during ventricular filling
40
Chordae tendinae
Tough fibrous cords prevent valves from everting
41
Papillary muscles
Contract w/ ventricle ctx-pull down chordae tendinae
42
Semilunar Valves
Aortic, Pulmonic; 3 valve cusps; Systole
43
Systole
Open when pressure in ventricles is greater than pressure in aorta and pulmonary artery (contraction and emptying)
44
Heart Layers
Endothelium, Myocardium, Epicardium (surrounded by pericardial sac)
45
Muscle Fibers
Arranged spirally
46
Heart Contraction
Wringing effect; blood moved up and out
47
Muscle Cell Connections
Intercalated discs; Desmosomes, Gap Junctions
48
Synctium
Some cardiac cells spontaneous AP w/o nervous innervation; Electrical impulse spreads via gap junctions-atria contract together, then ventricles contract together; No gap junctions between atria or between atria and ventricles (specialized conduction system)
49
Electrical Activity of Heart
AP, contraction, eject blood (99% cells); AP generated by cardiac cells-autorhythmicity
50
Autorhythmic cells
No resting potential, pacemaker function, potential slowly depolarizes (drifts) between AP until threshold
51
Ions Responsible for Pacemakers
Inc Inward Na+; Dec Outward K+; Inc Inward Ca+
52
Sinoatrial (SA) Node
Right atrium near SVC (super vena cava)
53
Atrioventricular (AV) Node
Base of right atrium near septum and AV junction
54
Bundle of His
Starts at AV node and travels through IVS
55
Purkinje Fibers
Small terminal fibers extend from Bundle of His and spread throughout ventricular myocardium
56
Pacemaker of Heart
Autorhythmic cells different rates of depolarization; once polarized-spread via gap junctions and specialized conduction system; SA Node-fastest 70 AP/min
57
Problems with Pacemaker
Damage SA node, AV node takes over-slower 30 beats/min; If conduction blocked between atria and ventricle-disconnect, complete heart block (heart attack)-need artificial pacemaker; Ectopic focus-faster than SA-Premature Ventricular Contraction (PVC)-anxiety, lack of sleep, excess caffeine, nicotine, EtOH
58
Electrocardiogram
Electrical currents spread; Small part reaches body surface; Recording of activity EKG; 12-lead (connections between two electrodes on body)
59
Diseases DX via EKG
Abnormal heart rate/rhythm, cardiac myopathies (heart damage)
60
Tachycardia
Too fast
61
Bradycardia
Too slow
62
Arrhythmia/Dysrhythmia
Abnormal rhythm
63
Atrial flutter
Rapid, regular (2:1, 3:1)
64
Atrial fibrillation
Rapid, irregular, no P waves; ventricles irregular; pulse deficit
65
Ventricular fibrillation
Chaotic, death
66
Heart block
P wave independent from QRS
67
Myocardial ischemia
Lack of oxygen
68
Myocardial infarction
Losing heart muscle
69
Heart Sounds
First: low-pitched, soft, long "lub'; closure of AV valves; Systole. Second: higher pitch, shorter, "dub"; Closure of semilunar valves; Diastole
70
Murmur
Abnormal heart sound; cardiac disease; functional disease (young)
71
Stenotic Valve
Stiff, doesn't open completely
72
Insufficient Valve
Can't close completely, regurgitation
73
Rheumatic Fever
Both stenotic and insufficient valves
74
Cardiac Output
Volume of blood pumped by each ventricle per minute; CO = HR X SV; SV = 0.92 X weight (kg)
75
Parasympathetic
Vagus nerve; acetylcholine; atrium, SA, AV nodes; decrease HR
76
Sympathetic
NE, epinephrine; atria, SA, AV nodes, ventricles; increase HR; inc CTX strength; eject more blood due to inc Ca+ influx
77
Ejection Fraction
Proportion of blood in ventricle that is pumped out; Indicates contractibility; Normal 50-75%; Heart failure 30% or less
78
Heart Failure
Inability of Cardiac Output to keep up w body's demands; 5mil Amer; 50% die in 5yrs; Damage to heart muscle (heart attack); Prolonged pumping against increased afterload (HBP)
79
Coronary Arteries
Supply O2 and nutrients to muscle; No diffusion-airtight endothelium and muscle too thick; 70% Diastole, 30% Systole; Extra blood to heart via vasodilation (nitroglycerin prescriptions)
80
Coronary Artery Disease
Coronary blood flow doesn't keep up w O2 needs; Complications-leading COD in US; Vascular spasm; Atherosclerosis (Thromboembolism, Angina pectoris, Heart attack)
81
Flow Rate
F = ^P/R (F=flow rate, ^P=pressure gradient, R=resistance)
82
Pressure Gradient
Difference in pressure between beginning and end of vessel; CTX heart main driving force BF
83
Resistance
Hindrance/opposition to BF; friction between fluid and vessel walls
84
Resistance Factors
Viscosity, length, radius (R~1/r^4)
85
Systemic Circulation
Heart, arteries, organs (arterioles, capillaries, venules), veins, heart; BF to each organ depends on arterioles
86
Arteries
Rapid-transit passageway from heart to organs; heart CTX-systole-pumps, greater vol enters than leaves; BF continuous-elastic recoil
87
Pressure Reservoir (Arteries)
Driving force for BF when heart relaxing (diastole)
88
Elastic Recoil (Arteries)
Highly elastic arteries expand temp to hold excess vol-store pressure nrg; Heart relaxes, arteries passively recoil and push blood downstream into smaller vessels
89
Systolic Pressure
Max P exerted on arteries when ventricle contracts (systole) pumping blood into arteries
90
Diastolic Pressure
Min P w/in arteries when blood drains from arteries into smaller vessels downstream (diastole-heart at rest)
91
Mean Arterial Pressure (MAP)
Avg pressure driving blood forward into tissue; MAP = DP + 1/3[Pulse Pressure (SP-DP)]; MAP = CO x TPR
92
Arterioles
Main resistance vessels, dec mean pressure, leads to pressure differential BF from heart to organs; Radius adjusted to variably distribute CO among organs depending on needs and help regulate BP
93
Vasoconstriction
Constricts w contraction; Inc SNS
94
Vasodilation
Dilates w relaxation; Dec SNS
95
Vascular Tone
Constant partial constriction
96
Exercise
Inc CO; Vasodilation skeletal muscle and heart; Vasoconstriction kidneys and digestive tract; Brain supply constant
97
SNS
Vasoconstriction dec BF to downstream organ but inc upstream arterial pressure increasing driving force for BF to all organs (esp brain); Brain cardiovascular control center medulla controls output
98
Norepinephrine-SNS
alpha-adrenergic receptors cause vasoconstriction (except brain)
99
Adrenal Medulla
Contributes epinephrin, norepinephrine, vasopressin, angiotensi II
100
NE
Combines w same alpha receptors
101
E
Combines w beta-2 receptors (and alpha); Greater affinity for B2-vasodilation; Abundant heart and skeletal; Kidney and digestive alpha only
102
Vasopressin
Maintain H2O balance by reg amt kidney retains during urine formation (vasoconstrictor)
103
Angiotensin II
Part hormonal pathway reg salt balance (vasoconstrictor)
104
Hemorrhage
Loss of blood, vasopressin and angiotensin II restore plasma volume and BP
105
Capillaries
Site of exchange; Diffusion-short distance, thin wall, large SA, slow BF
106
Interstitial Fluid
Exchanges between blood and tissue not made directly; Exchange w ECF-movement across PM, passive or active
107
Exchange
Passive diffusion; Bulk flow
108
Bulk Flow
Vol protein-free fluid filters out capillary into ISF then reabsorbed; occurs due to changes in hydrostatic and oncotic pressure; Cap BP and ISF colloid P force fluid out of capillary, Plasma colloid and ISF hydrostatic P force fluid into capillary
109
Ultrafiltration
P cap > P outside - fluid pushed out via pores (begin cap)
110
Reabsorption
P out > P cap - fluid returns to cap (end cap)
111
Lymphatic System
Normal-more fluid filtered out than reabsorbed; Extra fluid picked up by lymphatic; Returns excess ISF to blood as lymph; Empties into venous system near where blood enters RA; Return excess filtered fluid; Defense against disease (percolates through lymph nodes); Transport of absorbed fat (from dig tract); Return of filtered protein
112
Edema
Excess ISF (swelling); Dec concn plasma proteins; Inc permeability cap to plasma proteins (trauma); Inc venous pressure (CHF, pregnancy); Blockage lymph vessels
113
Veins
Low R; Blood reservoir; Resting-60% blood; Slower transit time
114
Venous Return
Volume entering each atrium per min from veins; More returned, more pumped
115
Blood Pressure
MAP main driving force; monitored and regulated; BF depends on MAP and degree vasoconstriction arterioles
116
Short-term BP Regulator
Baroreceptors; Influence heart and blood vessels adjust CO and TPR to restore BP to normal; Carotid sinus (brain); Aortic arch (body); Mechanoreceptors sensitive to changes in MAP and PP; Continuous AP in response to pressure w/in arteries: Inc BP, inc firing, cardio ctrl ctr-medulla, alters SNS & PNS
117
Long-term BP Regulator
Adjusting total blood volume by restoring salt and H2O balance via urine and thirst
118
Hypertension
Control mechanisms don't function properly or unable to completely compensate; 140/90 (Normal-120/80; Hypo-100/60)
119
Secondary Hypertension
10%-def cause (Renal, Endocrine, Neurogenic)
120
Primary Hypertension
90%-unknown cause; Genetic propensity, Hastened or worsened by obesity, stress, smoking, dietary habits (NaCl intake)
121
Hypertension Complications
CHF, stroke, heart attacks, inc stress on vessels and heart (latter inc workload, pumping against inc TPR)
