Exam 2 LO Flashcards
1
Q
Synapse between a somatic motor neuron and skeletal muscle fiber
A
Neuromuscular junction
2
Q
What is located in the motor end plate
A
ACh receptors, Junctional folds
3
Q
Steps for neuromuscular transmission of skeletal muscle beginning with somatic neuron generating action potential
A
- Somatic neuron generates action potential from VG Na/K channels to presynaptic axon terminal
- Depolarization opens VG Ca2+ channel and Ca2+ enters channel
- ACh released
- ACh binds to AcH ligand gated receptor on motor end plate
- Binding allows Na+ influx
- Membrane depolarizes, creating an EPP (graded potential) that initiates the action potential
- Opening of VG Na+ channels allows AP to travel through muscle fiber (EPP spreads like Local current flow)
4
Q
3 ways neurotransmitter (ACh) is removed from synaptic cleft after nerve signaling
A
Reuptake of ACh
Enzyme degradation by AChE
Diffusion
5
Q
Excitation Contraction Coupling process (think of picture Dr wu drew of the t tubule)
A
- AP propagates fast along sarcolemma into t tubules, depolarizing the cell
- AP in t tubules stimulates the DHPR from Ca2+ release
- DHPR is linked to RyR, Ca2+ binds to RyR in SR and RyR opens releasing Ca2+
- Ca2+ exits SR, flowing down concentration gradient into sarcoplasm
- Ca binds to troponin on actin, changing the shape, and moving tropomyosin away from the myosin binding sites on actin
- Myosin head hydrolysis ATP
- Myosin head binds to actin and phosphate is released forming a crossbridge
- Myosin head executes a power stroke
- Crossbridge remains attached to actin until a new ATP binds to myosin
6
Q
What happens in a power stroke
A
Myosin head pivots, pulling thin filament past thick filament toward the center of the sacromere—releasing ADP
7
Q
Allows AP to move quickly from cell to cytosol
A
T tubules
8
Q
Stores calcium
A
SR
9
Q
Thin filament, calcium sensor triggers muscle contraction
A
Troponin
10
Q
Blocks myosin binding sites on thin filament during relaxation, moves out of the way during muscle contraction
A
Tropomyosin
11
Q
In the presence of calcium in the contraction cycle…
A
Myosin and actin bind and form a crossbridge
12
Q
Sliding of the thin filaments and Z discs coming closer together results in what sacromere length
A
Shortened length
13
Q
What is the role of SERCA
A
Pumps calcium from sarcoplasm into the SR after contraction
14
Q
What leads to stop in muscle contraction and muscle relaxes
A
SERCA
15
Q
SERCA pumps calcium back into SR going
A
Against gradient
16
Q
3 roles of ATP in skeletal muscle contraction and relaxation
A
- ATP hydrolysis by SERCA provides energy for active transport of calcium into SR (muscle relaxation)
- ATP provides energy for crossbridge
- New atp binding to myosin allows for detachment
17
Q
Energy sources for muscle contraction
A
Creatine Kinase, glycolysis, oxidative phosphorylation
18
Q
Creatine kinase, glycolysis, and oxidative phosphorylation
- type of reaction
A
Creatine kinase= 1 step rxn
Glycolysis and phosphorylation= multi step
19
Q
What must occur first before oxidative phosphorylation
A
Glycolysis to make 2 pyruvic acid from glucose
20
Q
Transfers phosphate to ADP to regenerate ATP
A
Creatine kinase
21
Q
Storehouse of high energy phosphate at rest
A
Creatine kinase
22
Q
How long does creatine kinase last? What does it power? How fast is atp production?
A
Provides atp during first few seconds of contraction, atp production rapid but limited, powers very short periods of muscle activity
23
Q
Glycolysis is what kind of process (think metabolism)
A
Anaerobic, converts 1 glucose to 2 ATP
24
Q
Occurs in high intensity exercise
A
Glycolysis
25
Glycolysis powers what type of activity?
Powers short periods of muscle activity
26
Oxidative phosphorylation requires what
O2
27
Oxidative phosphorylation converts what to what
1 glucose to 36 atp (and fatty acids and amino acids)
28
Oxidative phosphorylation occurs in the
Mitochondria
29
Oxidative phosphorylation, after glycolysis, gives what fuel
Fatty acids
30
Oxidative phosphorylation powers what exercise
Powers extended periods of muscle activity
31
Muscle fiber types are classified by their
Max velocity or shortening and pathways for ATP formation
32
Postural muscles and endurance activities use what muscle fiber
Slow oxidative
33
Slow oxidative muscle fibers:
- Diameter size
- Less or more tension development
- type of metabolism
- fast or slow myosin ATPase
- resistance to fatigue
Small diameter
Slow tension development
Aerobic metabolism, uses oxidative phosphorylation
Slow myosin ATPase
Resistant to fatigue
34
Fast oxidative muscle fiber:
- diameter
- tension development
- type of metabolism
- fast or slow myosin ATPase
- resistance to fatigue
Large diameter
Faster tension development than slow oxidative muscles
Anaerobic and aerobic (oxidative phosphorylation and glycolysis)
Fast myosin ATPase
Somewhat resistant to fatigue
35
Sprinting involves what type of muscle fiber
Fast oxidative
36
Fast glycolytic muscle fibers:
- tension development
- diameter
- fast or slow myosin ATPase
- type of metabolism
- fuels what?
- myoglobin amount
- resistance to fatigue
Most tension, fastest development
Large diameter
Fast myosin ATPase
Small myoglobin amounts, less capillaries
Prone to fatigue
37
What type of muscle fiber controls explosive movements such as weight lifting or fast, forceful movements
Fast glycolytic
38
Factors that do NOT contribute to muscle fatigue
absence of ATP or lactic acid
39
Factors that do contribute to muscle fatigue
High extracellular K concentration, buildup of ADP that inhibits crossbridge, and disruption of calcium regulation (malfunctioning calcium channels on the SR)
40
Tension is maintained in what muscle fiber
Slow oxidative
41
Able to maintain initial tension than decreases to fatigue
Fast oxidative muscle fiber
42
Most likely to fatigue rapidly
Fast glycolytic muscle fiber
43
A motor neuron and the population of muscle fibers it innervates
Motor unit
44
When a large amount of tension needs to be generated…
More motor neurons are recruited
45
What factors determine the tension developed in a whole muscle
Motor unit size and recruitment
46
Affects the amount of tension the muscle can generate
Motor unit size
47
Muscles that control precise movements, such as the hands have what size motor units
Small (less muscle fibers)
48
When a muscle needs to generate more force during a contraction, more motor units are activated
Motor unit recruitment
49
How does motor unit recruitment work
Smaller and weaker motor units are recruited first and then larger/stronger motor units added as needed
50
Duration of a muscle fiber action potential vs. muscle contraction
Muscle fiber Action potential lasts a few seconds (shorter), contraction (twitch) lasts longer because of latent, contraction, and relaxation phase
51
Why is contraction longer than action potential
Shortness of an AP allows frequency to increase, continuing to release calcium until tetanus
52
Brief contraction of a group of muscle fibers by a single action potential
Twitch
53
1 stimulus equals how many twitches
1
54
Muscle contraction where action potentials continue to fire because calcium continues to be released
Tetanic contraction
55
Once calcium is present, it binds to troponin and pulls all the tropomyosin away. What is the relationship between this and tetanus
All the myosin binding sites are exposed, max contraction reached
56
Is a twitch or tetanic contraction smaller, why?
Twitch because less calcium is in the sarcoplasm and ATPase can catch up to calcium being released by 1 stimulus
57
Isometric vs isotonic muscle contractions
Isometric: tension generated but muscle length doesn’t change while contracting
Isotonic= tension stays the same but muscle length changes
58
Trying to lift an object too heavy is what contraction
Isometric
59
A bicep curl is what kind of contraction
Isotonic
60
How long is the latent period in isometric contractions? Isotonic?
Isometric= short, less calcium released and can’t generate enough tension
Isotonic= longer, able to develop enough tension
61
Occurs to maintain posture and support objects in a fixed position
Isometric contraction
62
Tension develops in the muscle, but it doesn’t reach the force needed to move the load
Isometric contraction
63
Used for moving objects and body movements
Isotonic contraction
64
Tension generated during contraction is great enough to exceed the load of an object, shortening the muscle
Isotonic contraction
65
More calcium releases results in a
Higher frequency
66
More Myosin binding sites exposed=
More contractions
67
The stretch reflex involves
The tendon reflex involves
The knee jerk reflex involves
The withdrawal reflex involves
Muscle spindles
Golgi tendon organs
Muscle spindles
Nociceptors
68
Somatic nervous system system:
- pathway
- effectors
- neurotransmitters
- receptor type on effector organ
- action of neurotransmitter on effector
-voluntary or involuntary control
- one neuron pathway
- skeletal muscle
- ach
- cholinergic
- always excitatory (contraction of skeletal muscle)
- voluntary control
69
Autonomic nervous system system:
- pathway
- effectors
- neurotransmitters
- receptor type on effector organ
- action of neurotransmitter on effector
-voluntary or involuntary control
- two neuron pathway
- smooth, cardiac, glands
- ach or norepi
-cholinergic or adrenergic
- excitatory or inhibitory
- involuntary
70
Describe the two neuron pathway for the autonomic nervous system
1. Preganglionic neuron that extends from CNS to an autonomic ganglion
2. Post ganglionic neuron extends from autonomic ganglion to effector
OR
preganglionic neuron may extend from CNS to synapse with chromaffin cells of medulla
71
Responds to overstretching of muscle, controlling muscle length
Muscle spindles
72
Sensory input directly synapses to motor neuron or effector
Monosynaptic reflex arc
73
Sensory input enters the spinal cord in the same side motor output exits
Ipsilateral reflex
74
Interneurons connects sensory and motor neurons
Polysynaptic reflex arc
75
Respond to excessive muscle tension, causes relaxation, protects tendon and muscle from damage
Golgi tendon organs
76
What happens in a knee/patellar jerk reflex
1. Tap on tendon stimulates muscle spindle to stretch
2. AP travels
3. In integrating center, sensory neuron synapses in spinal cord activating motor neuron
OR
Interneurons inhibits motor neuron, relaxing hamstring allowing extension of leg through reciprocal innervation
4. Motor neuron excited and leads to effector of quadriceps contracting, leg swinging forward
77
Explain the withdrawal reflex by a nociceptor
1. Pain stepping on sharp object stimulates nociceptor
2. Sensory neuron excited & in integrating center activates many Spinal cord segments
3. Multiple motor neurons excited and either ascend to pain and postural adjustment pathways or withdrawal reflex pulls foot away from stimulus by contracting leg muscles
78
What level of motor control of brain regions coordinates movements based on intention and sensory feedback
Middle level
79
Made up of several masses of gray matter found in cerebral hemispheres
Basal nuclei
80
Controls inititation of movement, suppression of unwanted movements, regulate muscle tone, and regulate non motor processes such as attention, memory, plannings and emotional behavior
Basal nuclei
81
Monitors intention for movement and actual movement
Cerebellum
82
Compares command signals with sensory information and sends corrective feedback
Cerebellum,
83
What brain regions are in the middle level of motor control
Basal nuclei and cerebellum and brainstem
84
Upper motor neurons from cerebral cortex make up the
Higher centers of control in motor cortex
85
Involves the sensory, motor, and association cortex, and brainstem
Higher centers in motor control
86
Helps control posture and balance, regulation of muscle tone, assists with movements of body in response to unexpected stimuli, controls precise and voluntary movements of upper limbs
Brainstem
87
Voluntary control of muscles of the limbs and trunk though the corticospinal pathway
Primary motor cortex
88
What tract crosses at the midline if the body at the medulla, responsible for precise and agile movements of hands and feet
Lateral tract
89
What tract crosses at the midline at spinal cord, responsible for trunk and upper limbs
Ventral tract
90
Right cerebral cortex controls muscles on the…
Left side of body
91
Smooth vs skeletal muscle relaxation
Smooth muscle relaxation: decrease calcium in sarcoplasm, dephosphorylation or myosin phosphate
Skeletal: new atp mist bind to myosin on actin for crossbridge to detach
92
Smooth muscle vs skeletal muscle activation
Smooth muscles have slower contraction speed and contraction is triggered by calcium changes to the thick filament vs the thin filament in skeletal muscle
93
Smooth muscles have troponin—true or false
False, calcium binds to calmodulin instead to activate cross bridge
94
Why do smooth muscles contract slower than skeletal muscle?
1. No calcium burst, slower diffusion rate
2. Rate of action potential, can be uncoupled
3. Slower crossbridge formation (no troponin)
95
Role of calmodulin in smooth muscle
Calcium binds to calmodulin, which binds to MLCK, transfers phosphate and phosphorylated myosin binds actin (forms crossbridge)
96
There is no need to trigger an action potential in __ muscle because…
Smooth, doesn’t rely on membrane changes from AP
97
Calcium sources that contribute to smooth muscle activation (contraction)
Extracellular calcium (main source)= enters down gradient by VG calcium channels
SR= release calcium by g coupled receptor
98
Ligand gated channels, stretch activated sodium and calcium channels are located in
Extracellular concentration for calcium
99
Dip into z discs, action potentials travels through this….contains the DHPR
T tubules
100
RyR releases calcium into cell when
Triggered by calcium binding
101
SR contains what
RYR and SERCA
102
Explain the contractile unit in cardiac muscle
Calcium binds to troponin, shortens sacromere
Unbinds and relaxes sacromere
103
Force generation of cardiac muscle is directly proportional to
Number of active cross bridge (determined by calcium concentration bound to troponin)
104
Shorter sacromere results in
Contraction
105
Connect myocytes
Intercalated discs
106
Intercalated discs contain
Desmosomes and gap junctions
107
Function of a desomosome? Gap junction?
Desmosome transmits force
GJ transfers electrical current in the form of calcium, allows for communication and transfer of materials between cells
108
Why do gap junctions in cardiac muscle work as a pump?
AP quickly spreads to all fibers, contracting together as a single unit
109
In cardiac cells, this provides Energy to contract and relax, higher in number and larger compared to skeletal muscle
Mitochondria
110
Proteins in the cardiac muscle responsible for excitation contraction coupling
DHPR and RyR
111
DHPR is a
voltage gated calcium channel
112
RyR is a
SR Ca release channel
113
What protein responsible for calcium induced calcium release
DHPR
114
What is the difference between skeletal and cardiac muscle cells? Speed of contraction? Role of DHPR?
Skeletal: fast to contract and relax
-short refractory periods to allow tetanus
- DHPR is just a voltage sensor
-mechanically coupled to AP (allowing calcium release from SR)
Cardiac: a little slower, prevents tetanus
- DHPR is a VG ca channel
- calcium mostly comes from SR, not as much ECF
115
How does the length of the refractory period prevent tetany in cardiac cells?
Plateau phase Allows for complete contraction and relaxation of cardiac muscle
-crossbridge effects amplitude not frequency
116
An SA nodal cell has what kind of Rmp
Unstable
117
Where are funny channels located
Sa nodal cells
118
What is the role of a funny channel
Causes unstable RMP because it’s permeable to sodium and potassium at the same time
119
In the depolarizing phase of an sa nodal cell what channels open
Calcium
120
What channels open at a plateau phase of a cardiac myocyte
Calcium
121
Flow of depolarization
SA Node
Internodal pathways
AV Node
Bundle of His
Intervenricular septum (left and right bundles split into bundle branches)
Purkinje fibers in ventricles
122
What’s the difference between AV Nodal cells and Purkinje fibers
AV nodal cells have slower electrical activity and less gap junctions and nodal cells
Purkinje fibers have fast electrical activity and more nodal cells and gap junctions
123
2 electrodes detecting potential differences because depolarization or repolarization is in progress
Deflection
124
Lead can’t detect change in electrical activity in…
An isoelectric event
125
Electrical activity is __ to a lead
Perpendicular
126
What equals an interval
Segment plus deflection
127
An upward deflection is a __
A downward deflection is a __
Depolarization
Repolarization
128
Draw an ecg reading and explain what events happen at the different sections
P wave= atrial systole, atrial depolarization
PRQ segment= atria fully contracted, av nodal delay
QRS segment= ventricular systole, ventricular
depolarization and atrial repolarization (can’t see)
ST complex= ventricles fully contracted, ventricles fully depolarizaed
T wave= early diastole of ventricles, repolarization of ventricles
TP segment= full diastole, fully repolarized ventricles
129
What makes up a positive deflection (ventricular diastole)
Repolarization x opposite
130
In to out, endocardium to epicardium is what kind of electrical activity
Depolarization
131
Epicardium to endocardium, out to in is what electrical activity (and what wave)
Repolarization, t wave
132
What lead is most parallel to overall direction of depolarization and electrical activity (MVA)
Lead 2
133
What sets the basic heart rate
SA node and nodal cells
134
What would happen if all the nerves to the sa node was severed?
Heart would still beat
135
Normal cardiac output is what? Formula?
CO= SV x HR
5 L/min
136
How to find stroke volume
EDV- ESV
137
amount of blood ejected out of the heart in 1 minute
Cardiac output
138
Amount of blood ejected per bear
Stroke volume
139
Ensure one way flow of blood
Valve
140
What are the kinds of valves
Atrioventricular valves and pulmonary/aortic valves
141
Types of AV valves
Tricuspid= right av valve
Mitral or bicuspid= left av valve
142
What is the important thing to remember about opening and closing of valves
All 4 valves can be closed at the same time but never open at the same time; set of valves open at a time
143
What is ventricular diastole
Filling of blood; aortic and pulmonary valves closed & av valves open
144
What is ventricular systole
Ejecting of blood in ventricles
Av valves close, pulmonary and aortic valve open
145
Lub vs. dub sounds
S1= lub, after qrs complx
S2= dub, after t wave
146
Aortic valves close in what sound
Lub
147
Aortic and pulmonary valves close in what sound
Dub
148
Contractility is regulated by…
Heart rate is regulated by…
Contractility= sympathetic nervous system
Heart rate= sympathetic and parasympathetic ns
149
Parasympathetic nervous system
- releases what
- rate of depolarization (heart rate)
- innervates what?
AcH
Slows heart rate, slows rate of depolarization
Innervates nodes only: calcium permeability of nodal cells decrease
150
sympathetic nervous system
- releases what
- rate of depolarization (heart rate)
- innervates what?
Norepi released on beta 1 receptor
Speeds up rate of depolarization and heart rate
Innervates myocardium and nodes
151
What events occur at the cardiac cycle
1. Electrical
2. Mechanical
3. Pressure changes
4. Valve/ volume event
152
Example of electrical cardiac event
QRS ventricular depolarization
153
Example of mechanical event in cardiac cycle
Ventricular systole or diastole
154
Example of pressure changes in cardiac cycle
Increase in Left ventricular pressure when left av valve closes
155
Valve and volume event in cardiac cycle
Aortic valve opens, blood travels through aorta to body; blood leaves the ventricle (systole)
Example of volume event is stroke volume
156
What is ejection fraction
SV/EDV x 100
157
3 factors that regulate stroke volume
Preload, Contractility, afterload
158
Order of events beginning with atrial kick…
Atrial kick
Isovolumetric contraction
Ejection
Isovolumetric relaxation
Passive filling
159
Order of events that occur at the P wave:
- electrical event
- mechanical event
- pressure gradient (artery, atria, ventricle)
- valve event
- volume event
- atrial depolarization
- atrial contraction
- atria> ventricles and artery> ventricles
- av valves are open, semilunar valves are closed
- atrial kick
160
Order of events that occur at the QRS complex:
- electrical event
- mechanical event
- pressure gradient (artery, atria, ventricle)
- valve event
- volume event
Ventricular depolarization
Ventricles contract
PVentricles> Patria, Partery > PVentricles
Av valves closed, s1 sound
Isometric contraction
161
Order of events that occur at the ST segment:
- electrical event
- mechanical event
- pressure gradient (artery, atria, ventricle)
- valve event
- volume event
Ventricles fully depolarized
Ventricles continue to contract
P ventricles> p atria, PVentricles> p artery
AV valves closed, SL valves open
Ejection
162
Order of events that occur at the T wave:
- electrical event
- mechanical event
- pressure gradient (artery, atria, ventricle)
- valve event
- volume event
- ventricular repolarization
- ventricles start relaxing
- PVentricles> patria, partery> PVentricles
- SL valves closed, s2 heart sound
- Isovolumetric relaxation
163
Order of events that occur at the Isoelectric between T and P waves:
- electrical event
- mechanical event
- pressure gradient (artery, atria, ventricle)
- valve event
- volume event
Ventricles fully repolarized
Ventricles fully relaxed
P atria> p ventricle and partery> p ventricle
AV valves open, SL valves closed
Passive filling
164
What effect does an increase in venous return have on the heart
Stretches the heart muscle and larger stroke volume
165
What does the frank starling law say
More you fill the heart, the more forceful the ejection, increase EDV, increase SV
166
EDV is determined by the
Venous return, proportional to cardiac output
167
Degree of stretch of the heart by the blood in the ventricles, amount of blood before ejection (EDV)
Preload
168
What were to have if a cardiac muscle could overstretch
Decrease number of cross-bridges and decrease force
169
What is the length tension relationship?
The more EDV, the more SV unless EDV goes past 300 mL them SV decreases
170
What influences venous return
Sympathetic innervation with norepi, skeletal muscle and respiratory pump
171
The more calcium inside the SR, the higher
Number of crossbridges
172
Contractility is affected by
Inotropes
173
What is the effect of a positive inotrope
Increase Contractility, increase calcium concentration, increase stroke volume
174
What effect does a negative inotrope have
Decrease contractility, decrease stroke volume
175
The sympathetic nervous system has a __ inotropic effect; what is it?
Positive; norepi binds to b1 receptor—> atp is converted into cAMP—> cAMP activates kinase a which causes faster calcium cycling and more crossbridges
176
What has the biggest influence on resistance
Radius
177
What is vasodilation
Increase in radius, decrease in resistance and increase blood flow
178
What is vasconstriction
Decrease radius, decrease blood flow, increase resistance
179
Relationship between length and resistance
If length increases, resistance of vessels increases
180
Relationship between resistance and viscosity
Increase viscosity, increase resistance
181
Relationship between resistance and radius
Radius inversely proportional to resistance: increase in radius then decrease in resistance
182
If there’s no pressure change in Ohms law, then
No pressure gradient or blood flow
183
Relationship between blood flow and change in pressure
If change in pressure increases then blood flow increases
184
Relationship between blood flow and resistance
If resistance increases, blood flow decreases
185
Blood is directly proportional to __ and inversely proportional to
Pressure gradient( arterial resistance) and vascular resistance
186
Thin wall, slow blood flow, no smooth muscle
Capillaries
187
Greatest control of radius of vessel, has most smooth muscle, high resistance, innervates by SNS
Arteries or arterioles
188
Greatest radius, thin smooth muscle, less pressure
Veins or venules
189
2/3 of blood is stored where
Venous system
190
What does mean arterial pressure reflect
Systemic BP
191
How to calculate mean arterial pressure…
DP+ (PP/3)
PP= SP-DP
192
Estimate of pressure from aorta to vena cava
MAP
193
The aorta is
Compliant and elastic
194
Ability to stretch because of pressure change
Compliant
195
How does compliance work with the aorta and blood flow…
As stroke volume/blood enter the aorta it expands
196
__ more compliant then __
Veins, arteries
197
Compliance has what kind of blood flow vs. elastance
Stretch= pulsatile
Elastance= smooth
198
What is the concept of elastance
Ability of a vessel to return to its original shape after stretching
199
Elastance effect on arteries
Keeps blood flowing during diastole pressure
200
Greatest change in pressure is at the
Arteriole
201
Compare and contrast laminar vs turbulent flow
Laminar is smooth, no sound
Turbulent= blood bounces off vessel walls, loud, noisy (korotkoff sounds)
202
When is blood flow silent (laminar) and when is it turbulent (loud)
Pressure above 120 mmHg= cuff stops arterial flow and no sound heard
Pressure between 80-120 mmHg= Korotkoff sounds made by pulsatile blood through artery (systole)
Pressure below 80 mmHg=blood flow is silent (diastole)
203
Properties of arterioles in blood distribution
- innervated by?
-greatest control of?
Highly innervated by smooth muscle (sympathetics) and greatest control of radius from high resistance
204
Allow for control of distribution of cardiac output
Arterioles
205
Both blood pressure and blood flow in the arteries is what kind of blood flow?
Pulsatile
206
Pulsatile blood flow, increases during __ and decreases during __
Ventricular systole, diastole
207
Ejection of blood by ventricles into arteries is
Not continous
208
The most common indirect method of measuring systemic arterial blood pressure is referred to as an
Auscultatory
209
Characteristics of the continuous capillaries
No holes/clefts, only molecules can diffuse for gas exchange
210
characteristics of the discontinuous capillaries
not in full contact, large proteins/molecules go through (liver)
211
characteristics of fenestrated capillaries
small holes in endothelium, small molecules can pass through like ions (for filtration)
212
What controls blood flow in capillaries, rings of smooth muscle
precapillary sphincters
213
precapillary sphincters found on what end
arterial end
214
Precapillary sphincters close capillaries in response to
local (intrinstic factors)
215
When sphincters relax...
blood flows in
216
Vasodilation instrinsic factors for precapillary sphincters are
increased CO2 and decreased O2
217
Vasocontriction instrinsic factors for precapillary sphincters are
endothelin and metabolites
218
Blood flow is the __ in capillaries because
slowest, has the highest total cross sectional area
219
Capillaries vs arterioles with blood pressure
Capillaries have the lowest blood pressure and velocity
220
Starling's forces describe...
bulk flow (capillary exchange/transport)
221
From the interstitial space to capillary =
From the capillary to the interstitial space=
absorption, filtration
222
Bulk flow from filtration across a capillary depends on a balance of ....
hydrostatic and protein/osmotic pressure gradients
223
Hydrostatic and protein/osmotic pressure gradients favor....
Hydrostatic: filtration
Protein/osmotic= absorption (increase in protein in blood attracts water)
-Greater pressure inside the capillary than interstitial fluid
224
Roles of lymphatic vessels in the maintenance of interstitial fluid
Drains excess interstitial fluid from tissue spaces and returns it to the blood to maintain normal blood volume
- Filters pathogens
225
What happens if lymphatic system cannot keep up with drainage...
Edema: filtration is greater than absorption, inadequate drainage (fluid accumulates in interstitial space), capillaries more permeable
226
What side has a lower BP, venous or arterial
venous
227
How to mobilize venous return (increase preload...
1. Musculoskeletal and respiratory pump
2. Venous pressure gradient= need pressure change to move blood
3. Venous valves= 1 way valve
4. Sympathetics innervates veins through venoconstriction
228
Descrube the musuloskeletal and respiratory pump
M: when contraction occurs, muscle pinches off capillaries and force VR
R: when you inhale, diaphragm contracts and squeezes vena cava, pushing deoxy blood back to heart
229
Preload=
EDV
230
SV=
EDV-ESV
231
What are baroreceptors?
Stretch receptors, monitor BP in the walls of carotid arteries and aorta
232
What factors regulate blood flow
intrinsic
233
What intrinsic factors dictate vasoconstriction and dilation
Vasoconstriction= decrease Co2, increase endothelin, decrease O2 in lungs
Vasodilation= increase CO2, increase NO and metabolites, decrease O2 (systemic circulation)
234
What are factors regulate blood pressure
neural, hormones
235
extrinsic vasodilation factors? vasoconstriction?
Vasodilation= neural (NE binds to B2 adrenergic receptors) and hormonal (NO)
Vasoconstriction= neural (NE binds alpha 1 adrenergic receptor) and hormonal (Angiotension ii)
236
How do baroreceptors wok?
Respond to BP changes (stretch)--> sends AP
237
Baroreceptor is what kind of reflex
negative
238
Describe the parts of the baroreceptor reflex arc:
Stimulus= decrease BP change
Receptor= baroreceptor
Afferent: sensory neuron
Integrating center= cardiovascular center in medulla
Efferent/motor neuron= ANS (PNS--SA nodes/AV nodes and SNS--Nodes, myocardium, blood vessels)
Response: increase in BP
239
What effectors are dually innervated of the baroreceptor reflex
AV/SA nodes
240
Blood flow relationship to pressure and resistance
Blood flow proportional to pressure, but inversely proportional to resistance
241
Hydrostatic pressure is
blood pressure (fluid) + gravity
242
Effects distribution of blood in CV system
Hydrostatic pressure
243
In a standing person explain above and below the heart hydrostatic pressure
Above heart= low hydrostatic pressure, lowest at the head
Below heart= high hydrostatic pressure, greatest at the feet
BLOOD pulled toward the feet
244
Blood distribution and hydrostatic pressure are even throughout the body when?
Supine
245
Explain Orthostatic hypotension
getting dizzy or passing out when getting up too quick; blood pulled toward feet by gravity; barcoreceptors can't respond quick enough to change in hydrostatic pressure (comprimising VR, decrease in VR=decrease in CO)
246
Neural vs hormonal reflexes
Neural is faster, reacts to change in position
Hormone has longer term effects
