MIDTERM 2 Flashcards
(175 cards)
1
Q
What is the MAIN function of blood
A
- regenerates connective tissue
- moves gases, nutrients, wastes, and hormones
2
Q
Explain blood transportation
A
Blood transports formed elements, dissolved molecules, and ions
- Carries O2 from lungs and CO2 toward lungs
- Transports nutrients, hormones, heat, and waste products
3
Q
Explain what protects against pathogens and blood loss
A
- leukocytes, plasma proteins, and other molecules in the immune system protect against pathogens
- platelets and plasma proteins protect against blood loss
4
Q
Explain body temperature regulation
A
- blood absorbs heat from body cells
- heat is released at skin
5
Q
Explain body pH regulation
A
- blood absorbs acid & base from body cells
- blood has chemical buffers
6
Q
Explain fluid balance
A
- water from GI tract is added to blood
- water is lost through pee, skin, and breathing,
- fluid is exchanged b/w blood and interstitial fluid
- proteins and ions help w osmotic balance
7
Q
3 main components of blood and their percentages
A
Plasma - 55%
Buffy coat - <1%
Erythrocytes - 44%
8
Q
What does blood plasma consist of
A
Water, proteins, other solutes
9
Q
What does the buffy coat of blood consist of
A
Platelets and leukocytes
10
Q
What are the two things that erythrocytes lack and why
A
Lack nucleus and cellular organelles because they are packed with hemoglobin
11
Q
What is hemoglobin and what does it do
A
- red pigmented protein
- transports O2 and CO2
12
Q
What are the four globins of each hemoglobin molecule
A
- two alpha chains
- two beta chains
13
Q
What is the heme group that alpha and beta chains have…explain how it works
A
Porphyrin ring w an iron ion in the middle
- O2 binds to iron ion in order for each hemoglobin to bind four O2 molecules
14
Q
Explain oxygen binding to iron
A
- binding is weak
- fast attachment in lungs
- fast detachment in body tissues
15
Q
Explain CO2 binding to globin protein
A
- binding is weak
- attachment in body tissue and detachment in lungs
16
Q
Explain the 6 main steps of erythrocyte reproduction
A
- Stimulus:
- decrease in blood O2 level - Receptor:
- kidney detects decreased blood O2
- Control centre:
- kidney cells release erythropoietin into blood - Effector:
- erythropoietin stimulates red bone marrow which increases the rate of the production of erythrocytes - Net effect:
- increased numbers of erythrocytes enter circulation while lungs oxygenate them making blood O2 levels increase - ———-:
- kidney detects increased O2 levels which allows erythropoietin to be released by negative feedback
17
Q
Due to erythrocytes lacking organelles, what can they not synthesize
A
-proteins for repairs
18
Q
What is the max lifespan for erythrocytes
A
120 days
19
Q
What happens to old erythrocytes aka how do they die
A
They get phagocytize in spleen or liver
20
Q
Why are globins and membrane proteins broken down into aa’s
A
So that body can use them for protein synthesis
21
Q
How is iron from hemoglobin transported
A
By transferrin protein to liver
22
Q
What two storage proteins does iron from hemoglobin bind to
A
Ferritin and hemosiderin
*most is bound to go ferritin and is stored in liver and spleen
23
Q
Where is iron transported when needed for the production of erythrocytes
A
Red bone marrow
24
Q
6 main anatomical structures controlling heart activity
A
-SA node
-AV node
-Right atrium
-AV bundle
-Purkinje fibers
- R&L bundles
25
Explain how parasympathetic innervation decreases HR
- starts at medulla’s cardioinhibitory center
- relayed by vagus nerves
- right vagus innervates SA
- left vagus innervates AV
26
Explain how sympathetic innervation increases HR and force of contraction
- starts at medulla’s cardioacceleratory center
- relayed by neurons from T1-T5 segments of spinal cord
- extend to SA, AV, myocardium and coronary arteries
- increases coronary vessel dilation
27
2 steps of the conduction system
Initiation:
- SA node initiates AP
Spread of AP:
- An AP is propagated throughout atria and conduction system
28
Cardiac muscle cells- 2 steps
1. The AP
- AP is propagated across sarcolemma of cardiac muscle cells
2. Muscle contraction
- Thin filaments slide past thick ones and sarcomeres shorten within cardiac muscle cells
29
How do nodal cells in SA node initiate heartbeat
They depolarize and generate AP
30
RMP is about ___mV
60mV
31
What type of cells do not have a stable RMP
Nodal cells
32
Common membrane proteins of nodal cells
Sodium/ potassium pumps, calcium pumps, leak channels
33
Nodal cells- specific voltage gated channels
-Slow voltage gated sodium channels
-Fast voltage gated calcium channels
-Voltage gate potassium channels
34
What are the three steps to SA node cells exhibiting autorythmicity
1. Reaching threshold
2. Depolarization of AP
3. Repolarization
35
Explain autorhythmicity step 1
Reaching threshold:
- slow voltage gated Na channels open and Na comes in
- membrane potential changes from -60mV to -40mV
36
Explain autorhythmicity step 2
Depolarization of AP:
- fast voltage gated Ca channels open and Ca flows in
- membrane potential changes from -40mV to just above 0mV
37
Explain authorhythmicity step 3
Repolarization:
- Ca channels close and voltage gated K channels open, allowing K to go out
- membrane potential goes back to rest -60mV
- voltage gated Na channels open at -60mV and process begins again
38
At rest, how many seconds after the last does one SA node AP start
0.8 sec = 75 bpm
39
Similarities of nodal cells and neurons
Both fire AP’s
40
Differences between nodal cells and neurons
- neurons need stim to fire, nodal cells don’t
- nodal cells don’t have a stable RMP as they exhibit a pacemaker potential when Na channels open
- in neurons, AP depolarization is from Na entry while in nodal cells, it’s from Ca entry
41
AP of the heart- Step 1
SA node and atrial myocardium:
- AP generated at SA node.
- AP spreads through gap junctions between cardiac muscle cells throughout atria and to AV node
42
AP of the heart - Step 2
AV node:
- AP is delayed at AV node before it passes to AV bundle in interventricular septum
43
AP of heart - Step 3
Bundle branches and purkinje fibers:
- AV bundle conducts AP to left and right bundle branches and then to purkinje fibers
44
AP of the heart - Step 4
Ventricular myocardium:
- AP is spread through gap junctions between cardiac muscle cells in ventricles
45
Electrical events of cardiac muscle AP -step 1
Depolarization:
- impulse from conduction system opens fast voltage gated Na channels
- Na enters cell changing membrane potential from -90mV to +30mV
- voltage gated Na channels inactivate
46
Electrical events of cardiac muscle AP - step 2
Plateau:
- depolarization opens voltage gates K and slow voltage gates Ca channels
- K leaves cardiac muscle cells as Ca enters
**stimulates SR to release more Ca
- membrane depolarized
47
Electrical events of cardiac muscle AP - step 3
Repolarization:
- voltage gated Ca channels close while K channels are open
- membrane potential goes back to -90mV
48
Mechanical events of cardiac muscle cells
- Ca enters sarcoplasm from interstitial fluid and SR leading to contraction
As in skeletal muscle, it binds to troponin and initiates crossbridge cycling
- Ca levels decrease leading to relaxation
Channels close and pumps move it into SR and out of cell
49
T or F: cardiac muscle can exhibit tetany
FALSE
50
Explain refractory period of cardiac cells
- refractory period is long
- cells can’t fire a new impulse during refractory period
- plateau phase leads to refractory period of about. 250ms
- heart cell contracts and relaxes before it can be stimulated again
- making tetanus contraction impossible
51
Cardiac cycle- ECG
Electrical signals always occur before heart contraction
52
Cardiac cycle- Left ventricular volume
Atrial contraction adds a little more blood to ventricle to increase pumping efficiency
53
End diastolic volume
Greatest amount of blood in ventricle
54
End systolic volume
The lowest amount of blood in ventricle
55
Cardiac cycle- left atrial volume
Atrial pressure is low and relatively steady
56
Cardiac cycle- Left ventricular pressure
Dramatic increase in left ventricular pressure during ventricular systole
57
Cardiac cycle- left ventricular pressure and volume
Left ventricular pressure determines left ventricular vol
58
Cardiac cycle- Aortic pressure
Left ventricular pressure determines aortic pressure
59
Cardiac cycle- heart sounds
1. Aortic AL valve opens
2. Aortic SL valve closes (sound. 2)
3. AV valve closes (sound. 1)
4. AV valve opens
60
T or F: capillaries aren’t filled simultaneously
TRUE
61
How is blood flow measured
mL/minute
62
What 4 things are local blood flow dependent on
1. Degree of tissue vascularity
2. Myogenic response
3. Local regulatory factors altering blood flow
4. Total blood flow
63
What is profusion
Amount of blood flow to tissue
64
Degree of vascularization
Extent of vessels in a tissue
65
What type of tissues have high vascularity
Metabolically active tissues
66
Angiogenesis
Formation of new vessels (weeks to months)
67
Examples of angiogenesis
1. In skel mm in response to aerobic training
2. In adipose tissue w weight gain
3. In coronary vessels in response to blockage
68
Regression
Return to previous state of blood vessels
69
Myogenic response
Smooth mm in blood vessel wall keeps local flow constant by adjusting resistance
70
What kind of chemicals alter blood flow
Vasoactive chemicals
71
Vasodilators
Dilate arterioles and relax precapillary sphincters
- increases flow into capillary beds
72
Vasoconstrictors
Constrict arterioles and cause contraction of precapillary phincters
- decreases flow into capillary beds
73
Auto regulation & changing metabolic activity
When tissue controls blood flow …
When tissue activity increases, stimuli signal inadequate perfusion and act as vasodilators
74
What increases and decreases in auto regulation
O2 and nutrient levels decrease
CO2, lactic acid, H, and K increase
75
Auto regulation- negative feedback
When perfusion increases, vessels constrict
76
Reactive hyperemia
Increase in blood flow after its disrupted
Ex: going into warm room after being in cold
77
BP
Force of blood against vessel wall
78
BP gradient
Change in pressure from one end of vessel to other
-Highest in arteries and lowest in veins
79
Arterial BP
Blood flow in arteries pulses w cardiac cycle
80
What is systolic pressure
When ventricle contracts (systole)
- high pressure in arteries
- upper number of BP ratio- 120/80
81
What is diastolic pressure
When ventricles relax
- lowest pressure in arteries
- lower number of BP ratio
82
Pulse pressure
Pressure in arteries added by heart contraction
83
Mean arterial pressure (MAP)
Average arterial BP across cardiac cycle
- =diastolic pressure + 1/3 pulse pressure
84
Capillary BP
Pressure no longer fluctuates between systolic and diastolic
- needs to be high enough for exchange of substances
- needs to be low enough not to damage vessels
85
Arterial end of capillary BP number
40mm Hg
86
Venous end of capillary BP number
Below 20mm Hg
87
Venous return depends on what
Pressure gradient, skel mm pump, respiratory pump
88
What is the BP in venues compared to vena cava
20mmHg in venues and almost 0 in vena cava
89
Explain how skeletal muscle pump assists venous return from limbs
1. Mm contract, veins are squeezed
2. Blood is pushed and valves prevent backflow
3. Blood is moved faster during exercise
4. Blood pools in leg veins with prolonged inactivity
90
Respiratory pump assists in what
Venous return in thorax
91
Explain respiratory pump inspiration
1. Diaphragm contracts, so abdominal pressure increases and thoracic pressure decreases
2. Blood in abdominal veins is driven toward thoracic cavity
92
Explain respiratory pump expiration
1.Diaphragm relaxes, so thoracic pressure increases while abdominal pressure decreases
2. Blood in thoracic cavity veins driven toward heart
3. Blood in lower limbs allowed into abdominal veins
93
Explain poiseuilles law
- Resistance increases as length increases
- Resistance increases as viscosity increases
- Resistance decreases as radius increases
94
Function of angiotensin II
-Raises BP
- stimulates thirst
- decreases urine formation
- stimulates release of aldosterone and anti diuretic hormone
95
Aldosterone function & where is it released from
Increases absorption of Na ions and water in kidney
- released from adrenal cortex
96
Antidiuretic hormone function & released from
Maintains or elevates BP
- released from post pituitary
97
Effects of ADH
1. Increases water reabsorption in kidney
2. Stimulates thirst centre to increase fluid intake
3. In large amounts it causes vasoconstriction
98
3 blood vessels and their functions
1. Arteries
Take blood from heart to capillaries
2. Capillaries
Exchange substances b/w blood and tissues
3. Veins
Take blood from capillaries to heart
99
Tunica intima
Inner layer
- ENDOTHELIUM of simple squamous epithelium regulates blood vessel size
- subendothelial layer of areolar connective tissue
100
Tunica media
Middle layer
- contraction causes vasoconstriction ( narrows lumen)
- relaxation causes vasodilation (widens lumen)
101
Tunica externa
Outermost layer
- helps anchor vessel to other structures
- contains vasa vasorum
102
Explain the structure of arteries
1. Thicker tunica media and narrower lumen than veins
2. More elastic and collagen fibers
3. More resilient and resistant to changes in BP
103
Explain the structure of veins
- thicker tunica externa and larger lumen than arteries
- less elastic and collagen fibers
- wall collapses if there’s no blood in the vessel
104
Explain the structure of capillaries
1. Contains only tunica intima
2. Composed of endothelium and basement membrane
3. Thin wall allows for rapid gas and nutrient exchange
105
Blood vessels (5) biggest to smallest
1. Veins
2. Arteries
3. Venues
3. Arterioles
4. Capillaries
106
3 basic types of arteries
1. Elastic arteries
2. Muscular arteries
3. Arterioles
107
Elastic arteries
Biggest arteries
- take blood from heart to muscular arteries
Ex: aorta, pulmonary trunk, carotid, iliac
108
Muscular arteries
Medium arteries
- Distribute blood to diff regions
- muscle allows vasoconstriction and dilation
Ex: brachial artery, coronary
109
Arterioles
Smallest arteries
- bigger arterioles have 3 tunics
- small ones have only one layer of smooth mm
- smooth mm is somewhat constricted which is called vast other tone
110
Capillaries connect what to what
Arterioles to venules
111
continuous capillaries
-Endothelial cells make continuous lining
- intercellular clefts are the gaps b/w endothelial cells of capillary wall
- large particles can’t pass but small molecules can
Found in: mm, skin, lungs, cns
112
Fenestrated capillaries
-Endothelial cells make continuous lining but there are fenestrations
- fenestrations allow movement of small plasma proteins
- found in: places with lots of fluid transport
Ex: intestine capillaries absorbing nutrients
113
Sinusoids
- endothelial cells form an incomplete lining with big gaps
- no basement membrane really
- openings allow transport of big things
Found in : bone marrow, spleen, endo glands
114
Metarteriole
Vessel branch of an arteriole
115
True capillaries
Vessels branching from metarteriole
Make up bulk of capillary bed
116
Precapillary sphincter
Smooth mm ring at true capillary origin
- relaxation allows blood flow intO true capillaries
- contraction causes blood to bypass capillary bed
117
Vasomotion
Cycle of contracting and relaxing of precapillary sphincters
118
Venules
Smallest veins
- companions vessels w arterioles
- smallest ones are post capillary venules
- biggest ones have all three tunics
- merge to form veins
119
Blood reservoir percentages
70% in systemic circulation at rest
- 55% veins
-10% arteries
- 5% capillaries
- 18% pulmonary circulation
- 12% in heart
120
Simple pathway of blood vessels and give an ex
One major artery delivers blood to an organ or region
- arterioles feed into capillary beds
- capillary bed is drained by venules
- venules merge to one vein
Ex: splenic artery delivers blood to spleen; splenic vein drains organ
121
Arterial anastomosis (arterial joining)
2+ arteries converge to supply same region
122
Venous anastomosis
2+ veins drain same body region
123
Arteriovenous anastomosis
Transports blood from artery directly to vein
- allows areas to be bypassed if body is hypothermic
124
Portal system & path
Two capillary beds in sequence
Path: artery, capillary bed, portal vein, capillary bed, vein
125
Cross sectional area
Lumen diameter
126
Total cross sectional area
Sum of diameters of all vessel of a certain type
Ex: total cross editorial area of capillaries is largest bc there are so many capillaries
127
Blood flow velocity
Blood flow is slow in capillaries, allowing for exchange b/w blood and tissue fluid
128
What two things do endothelial cells use
pinocytosis and exocytosis
129
Bulk flow
Fluids flow down pressure gradient
- movement direction depends on net pressure of opposing forces
130
Filtration
When fluid moves out of blood
- large solutes are blocked
- occurs on arterial end of capillary
131
Reabsorption
When fluid moves back into blood
-occurs on venous end
132
What do hydrostatic and colloid osmotic pressure regulate
Bulk flow
133
What does hydrostatic pressure P cap do
Forces fluid out of capillary
134
Colloid osmotic pressure of proteins within capillary does what
Pulls fluid into capillary
135
Capillary hydrostatic pressure
Forces fluid outward thru capillary membrane
136
Interstitial fluid pressure
Opposes filtration when value is positive
137
Plasma colloid osmotic pressure
Opposes filtration causing osmosis of water inward through membrane
138
Interstitial fluid colloid osmotic pressure
Promotes filtration by causing osmosis of fluid outward through membrane
139
P wave
Electrical changes of ATRIAL DEPOLARIZATION in SA node
140
QRS complex
VENTRICULAR DEPOLARIZATION
Atria is also repolarizing
141
T wave
VENTRICULAR REPOLARIZATION
142
What contracts during the PQ segment, and then the ST segment
PQ: atria are contracting
ST: ventricles are contracting
143
Atrial repolarization is visible on an ECG… T or F
F
144
6 electrical events of the heart
1. Atrial depolarization
2. Atrial plateau
3. Atrial repolarization
4. Ventricular depolarization
5. Ventricular plateau
6. Ventricular repolarization
145
PR interval
When AP is transmitted through conduction system
146
QT interval
Time of ventricular AP
147
What are heart blocks
Impaired conduction
148
First degree AV block
PR prolongation
- slow conduction b/w atria and ventricles
149
Second degree AV block
Failure of some action potentials to reach ventricles
150
Third degree AV block
Complete
- failure of all AP’s to reach ventricles
151
Premature ventricular contractions
Result from stress, stimulants, or sleep deprivation
- abnormal AP within AV node or ventricles
152
Atrial fibrillation
Chaotic timing of atrial action potentials
153
Ventricular fibrillation
Chaotic electrical activity in ventricles
When u need an AED
154
Ventricular balance
Equal blood amount pumped by L&R sides of heart
155
Cardiac output
Amount of blood pumped by a single ventricle in one minute
L/min
Determined by HR and SV
156
Cardiac reserve
Capacity to increase cardiac output above rest level
157
Chronotropic agents
Change HR
- alter nodal cell activity
158
Positive chronotropic agents function
Increase HR
- NE and EPI are released and bind to nodal cells which increases firing rate
- phosphorylated Ca channels enhance Ca influx so cell fires sooner
159
What are the 4 chronotropic agents
TRH
Caffeine
Nicotine
Cocaine
160
TRH
Increases number of beta 1 adrenergic receptors on nodal cells
161
Caffeine
Inhibits breakdown of cAMP
162
Nicotine
Increases release of NE
163
Cocaine
Inhibits reuptake of NE
164
What are the 2 negative chronotropic agents
Parasympathetic activity
Beta blocker drugs
165
What do neg chronotropic agents do
Decrease HR
166
Neg chronotropic agents: parasympathetic activity
1. Parasympathetic axons release ACh onto model cells
2. ACh binds muscarinic receptors which are K channels
3. Channels open K exits cell making it more neg
4. Longer time for nodal cell to reach threshold, so HR slower.
167
Neg chronotropic agents: beta blocker drugs
- interfere w EPI and binding to beta receptors
- used to treat highBP
168
Autonomic reflexes
-baroreceptors and chemoreceptors send signals to cardiac center
- cardiac center influences sympathetic and parasympathetic systems to alter cardiac output as needed
169
Atrial reflex
Protects heart from over filling
- baroreceptors stimulated by increased venous return
- increased nerve signals to cardioacceleratory center
- increased excitation of sympathetic axons to heart
- HR increase to move blood through quick
170
Stroke volume
Amount of blood ejected in one beat
Influenced by: venous return, inotropic agents, and afterload
171
Venous return
Volume of blood returned to heart
- determines amount of ventricular blood prior to contraction
172
Frank starling law
As EDV increases, the greater stretch of heart wall results in more optimal overlap of thick and thin filaments
- heart contracts more forcefully when filled w more blood so SV increases
173
Inotropic agents
Change SV
- alter contractility
- due to changes in Ca available in sarcoplasm
- Ca levels relate to number of Crossbridges formed
174
After load
Resistance in arteries to ejection of blood by ventricles
- pressure that must be exceeded before bloods ejected
- atherosclerosis increases afterload
175
Recap- inotropic affects ________ while chronotropic affects ______
Inotropic: SV
Chronotropic: HR
