Exam 2 LO Flashcards
Synapse between a somatic motor neuron and skeletal muscle fiber
Neuromuscular junction
What is located in the motor end plate
ACh receptors, Junctional folds
Steps for neuromuscular transmission of skeletal muscle beginning with somatic neuron generating action potential
- 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)
3 ways neurotransmitter (ACh) is removed from synaptic cleft after nerve signaling
Reuptake of ACh
Enzyme degradation by AChE
Diffusion
Excitation Contraction Coupling process (think of picture Dr wu drew of the t tubule)
- 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
What happens in a power stroke
Myosin head pivots, pulling thin filament past thick filament toward the center of the sacromere—releasing ADP
Allows AP to move quickly from cell to cytosol
T tubules
Stores calcium
SR
Thin filament, calcium sensor triggers muscle contraction
Troponin
Blocks myosin binding sites on thin filament during relaxation, moves out of the way during muscle contraction
Tropomyosin
In the presence of calcium in the contraction cycle…
Myosin and actin bind and form a crossbridge
Sliding of the thin filaments and Z discs coming closer together results in what sacromere length
Shortened length
What is the role of SERCA
Pumps calcium from sarcoplasm into the SR after contraction
What leads to stop in muscle contraction and muscle relaxes
SERCA
SERCA pumps calcium back into SR going
Against gradient
3 roles of ATP in skeletal muscle contraction and relaxation
- 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
Energy sources for muscle contraction
Creatine Kinase, glycolysis, oxidative phosphorylation
Creatine kinase, glycolysis, and oxidative phosphorylation
- type of reaction
Creatine kinase= 1 step rxn
Glycolysis and phosphorylation= multi step
What must occur first before oxidative phosphorylation
Glycolysis to make 2 pyruvic acid from glucose
Transfers phosphate to ADP to regenerate ATP
Creatine kinase
Storehouse of high energy phosphate at rest
Creatine kinase
How long does creatine kinase last? What does it power? How fast is atp production?
Provides atp during first few seconds of contraction, atp production rapid but limited, powers very short periods of muscle activity
Glycolysis is what kind of process (think metabolism)
Anaerobic, converts 1 glucose to 2 ATP
Occurs in high intensity exercise
Glycolysis
Glycolysis powers what type of activity?
Powers short periods of muscle activity
Oxidative phosphorylation requires what
O2
Oxidative phosphorylation converts what to what
1 glucose to 36 atp (and fatty acids and amino acids)
Oxidative phosphorylation occurs in the
Mitochondria
Oxidative phosphorylation, after glycolysis, gives what fuel
Fatty acids
Oxidative phosphorylation powers what exercise
Powers extended periods of muscle activity
Muscle fiber types are classified by their
Max velocity or shortening and pathways for ATP formation
Postural muscles and endurance activities use what muscle fiber
Slow oxidative
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
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
Sprinting involves what type of muscle fiber
Fast oxidative
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
What type of muscle fiber controls explosive movements such as weight lifting or fast, forceful movements
Fast glycolytic
Factors that do NOT contribute to muscle fatigue
absence of ATP or lactic acid
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)
Tension is maintained in what muscle fiber
Slow oxidative
Able to maintain initial tension than decreases to fatigue
Fast oxidative muscle fiber
Most likely to fatigue rapidly
Fast glycolytic muscle fiber
A motor neuron and the population of muscle fibers it innervates
Motor unit
When a large amount of tension needs to be generated…
More motor neurons are recruited
What factors determine the tension developed in a whole muscle
Motor unit size and recruitment
Affects the amount of tension the muscle can generate
Motor unit size
Muscles that control precise movements, such as the hands have what size motor units
Small (less muscle fibers)
When a muscle needs to generate more force during a contraction, more motor units are activated
Motor unit recruitment
How does motor unit recruitment work
Smaller and weaker motor units are recruited first and then larger/stronger motor units added as needed
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
Why is contraction longer than action potential
Shortness of an AP allows frequency to increase, continuing to release calcium until tetanus
Brief contraction of a group of muscle fibers by a single action potential
Twitch
1 stimulus equals how many twitches
1
Muscle contraction where action potentials continue to fire because calcium continues to be released
Tetanic contraction
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
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
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
Trying to lift an object too heavy is what contraction
Isometric
A bicep curl is what kind of contraction
Isotonic
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
Occurs to maintain posture and support objects in a fixed position
Isometric contraction
Tension develops in the muscle, but it doesn’t reach the force needed to move the load
Isometric contraction
Used for moving objects and body movements
Isotonic contraction
Tension generated during contraction is great enough to exceed the load of an object, shortening the muscle
Isotonic contraction
More calcium releases results in a
Higher frequency
More Myosin binding sites exposed=
More contractions
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
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
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
Describe the two neuron pathway for the autonomic nervous system
- Preganglionic neuron that extends from CNS to an autonomic ganglion
- Post ganglionic neuron extends from autonomic ganglion to effector
OR
preganglionic neuron may extend from CNS to synapse with chromaffin cells of medulla
Responds to overstretching of muscle, controlling muscle length
Muscle spindles
Sensory input directly synapses to motor neuron or effector
Monosynaptic reflex arc
Sensory input enters the spinal cord in the same side motor output exits
Ipsilateral reflex
Interneurons connects sensory and motor neurons
Polysynaptic reflex arc
Respond to excessive muscle tension, causes relaxation, protects tendon and muscle from damage
Golgi tendon organs
What happens in a knee/patellar jerk reflex
- Tap on tendon stimulates muscle spindle to stretch
- AP travels
- 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
- Motor neuron excited and leads to effector of quadriceps contracting, leg swinging forward
Explain the withdrawal reflex by a nociceptor
- Pain stepping on sharp object stimulates nociceptor
- Sensory neuron excited & in integrating center activates many Spinal cord segments
- 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
What level of motor control of brain regions coordinates movements based on intention and sensory feedback
Middle level
Made up of several masses of gray matter found in cerebral hemispheres
Basal nuclei
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
Monitors intention for movement and actual movement
Cerebellum
Compares command signals with sensory information and sends corrective feedback
Cerebellum,
What brain regions are in the middle level of motor control
Basal nuclei and cerebellum and brainstem
Upper motor neurons from cerebral cortex make up the
Higher centers of control in motor cortex
Involves the sensory, motor, and association cortex, and brainstem
Higher centers in motor control
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
Voluntary control of muscles of the limbs and trunk though the corticospinal pathway
Primary motor cortex
What tract crosses at the midline if the body at the medulla, responsible for precise and agile movements of hands and feet
Lateral tract
What tract crosses at the midline at spinal cord, responsible for trunk and upper limbs
Ventral tract
Right cerebral cortex controls muscles on the…
Left side of body
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
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
Smooth muscles have troponin—true or false
False, calcium binds to calmodulin instead to activate cross bridge
Why do smooth muscles contract slower than skeletal muscle?
- No calcium burst, slower diffusion rate
- Rate of action potential, can be uncoupled
- Slower crossbridge formation (no troponin)
Role of calmodulin in smooth muscle
Calcium binds to calmodulin, which binds to MLCK, transfers phosphate and phosphorylated myosin binds actin (forms crossbridge)
There is no need to trigger an action potential in __ muscle because…
Smooth, doesn’t rely on membrane changes from AP
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
Ligand gated channels, stretch activated sodium and calcium channels are located in
Extracellular concentration for calcium
Dip into z discs, action potentials travels through this….contains the DHPR
T tubules
RyR releases calcium into cell when
Triggered by calcium binding
SR contains what
RYR and SERCA
Explain the contractile unit in cardiac muscle
Calcium binds to troponin, shortens sacromere
Unbinds and relaxes sacromere
Force generation of cardiac muscle is directly proportional to
Number of active cross bridge (determined by calcium concentration bound to troponin)
Shorter sacromere results in
Contraction
Connect myocytes
Intercalated discs
Intercalated discs contain
Desmosomes and gap junctions
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
Why do gap junctions in cardiac muscle work as a pump?
AP quickly spreads to all fibers, contracting together as a single unit
In cardiac cells, this provides Energy to contract and relax, higher in number and larger compared to skeletal muscle
Mitochondria
Proteins in the cardiac muscle responsible for excitation contraction coupling
DHPR and RyR
DHPR is a
voltage gated calcium channel
RyR is a
SR Ca release channel
What protein responsible for calcium induced calcium release
DHPR
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
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
An SA nodal cell has what kind of Rmp
Unstable
Where are funny channels located
Sa nodal cells
What is the role of a funny channel
Causes unstable RMP because it’s permeable to sodium and potassium at the same time
In the depolarizing phase of an sa nodal cell what channels open
Calcium
What channels open at a plateau phase of a cardiac myocyte
Calcium
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
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
2 electrodes detecting potential differences because depolarization or repolarization is in progress
Deflection
Lead can’t detect change in electrical activity in…
An isoelectric event
Electrical activity is __ to a lead
Perpendicular
What equals an interval
Segment plus deflection
An upward deflection is a __
A downward deflection is a __
Depolarization
Repolarization
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
What makes up a positive deflection (ventricular diastole)
Repolarization x opposite
In to out, endocardium to epicardium is what kind of electrical activity
Depolarization
Epicardium to endocardium, out to in is what electrical activity (and what wave)
Repolarization, t wave
What lead is most parallel to overall direction of depolarization and electrical activity (MVA)
Lead 2
What sets the basic heart rate
SA node and nodal cells
What would happen if all the nerves to the sa node was severed?
Heart would still beat
Normal cardiac output is what? Formula?
CO= SV x HR
5 L/min
How to find stroke volume
EDV- ESV
amount of blood ejected out of the heart in 1 minute
Cardiac output
Amount of blood ejected per bear
Stroke volume
Ensure one way flow of blood
Valve
What are the kinds of valves
Atrioventricular valves and pulmonary/aortic valves
Types of AV valves
Tricuspid= right av valve
Mitral or bicuspid= left av valve
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
What is ventricular diastole
Filling of blood; aortic and pulmonary valves closed & av valves open
What is ventricular systole
Ejecting of blood in ventricles
Av valves close, pulmonary and aortic valve open
Lub vs. dub sounds
S1= lub, after qrs complx
S2= dub, after t wave
Aortic valves close in what sound
Lub
Aortic and pulmonary valves close in what sound
Dub
Contractility is regulated by…
Heart rate is regulated by…
Contractility= sympathetic nervous system
Heart rate= sympathetic and parasympathetic ns
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
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
What events occur at the cardiac cycle
- Electrical
- Mechanical
- Pressure changes
- Valve/ volume event
Example of electrical cardiac event
QRS ventricular depolarization
Example of mechanical event in cardiac cycle
Ventricular systole or diastole
Example of pressure changes in cardiac cycle
Increase in Left ventricular pressure when left av valve closes
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
What is ejection fraction
SV/EDV x 100
3 factors that regulate stroke volume
Preload, Contractility, afterload
Order of events beginning with atrial kick…
Atrial kick
Isovolumetric contraction
Ejection
Isovolumetric relaxation
Passive filling
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
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
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
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
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
What effect does an increase in venous return have on the heart
Stretches the heart muscle and larger stroke volume
What does the frank starling law say
More you fill the heart, the more forceful the ejection, increase EDV, increase SV
EDV is determined by the
Venous return, proportional to cardiac output
Degree of stretch of the heart by the blood in the ventricles, amount of blood before ejection (EDV)
Preload
What were to have if a cardiac muscle could overstretch
Decrease number of cross-bridges and decrease force
What is the length tension relationship?
The more EDV, the more SV unless EDV goes past 300 mL them SV decreases
What influences venous return
Sympathetic innervation with norepi, skeletal muscle and respiratory pump
The more calcium inside the SR, the higher
Number of crossbridges
Contractility is affected by
Inotropes
What is the effect of a positive inotrope
Increase Contractility, increase calcium concentration, increase stroke volume
What effect does a negative inotrope have
Decrease contractility, decrease stroke volume
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
What has the biggest influence on resistance
Radius
What is vasodilation
Increase in radius, decrease in resistance and increase blood flow
What is vasconstriction
Decrease radius, decrease blood flow, increase resistance
Relationship between length and resistance
If length increases, resistance of vessels increases
Relationship between resistance and viscosity
Increase viscosity, increase resistance
Relationship between resistance and radius
Radius inversely proportional to resistance: increase in radius then decrease in resistance
If there’s no pressure change in Ohms law, then
No pressure gradient or blood flow
Relationship between blood flow and change in pressure
If change in pressure increases then blood flow increases
Relationship between blood flow and resistance
If resistance increases, blood flow decreases
Blood is directly proportional to __ and inversely proportional to
Pressure gradient( arterial resistance) and vascular resistance
Thin wall, slow blood flow, no smooth muscle
Capillaries
Greatest control of radius of vessel, has most smooth muscle, high resistance, innervates by SNS
Arteries or arterioles
Greatest radius, thin smooth muscle, less pressure
Veins or venules
2/3 of blood is stored where
Venous system
What does mean arterial pressure reflect
Systemic BP
How to calculate mean arterial pressure…
DP+ (PP/3)
PP= SP-DP
Estimate of pressure from aorta to vena cava
MAP
The aorta is
Compliant and elastic
Ability to stretch because of pressure change
Compliant
How does compliance work with the aorta and blood flow…
As stroke volume/blood enter the aorta it expands
__ more compliant then __
Veins, arteries
Compliance has what kind of blood flow vs. elastance
Stretch= pulsatile
Elastance= smooth
What is the concept of elastance
Ability of a vessel to return to its original shape after stretching
Elastance effect on arteries
Keeps blood flowing during diastole pressure
Greatest change in pressure is at the
Arteriole
Compare and contrast laminar vs turbulent flow
Laminar is smooth, no sound
Turbulent= blood bounces off vessel walls, loud, noisy (korotkoff sounds)
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)
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
Allow for control of distribution of cardiac output
Arterioles
Both blood pressure and blood flow in the arteries is what kind of blood flow?
Pulsatile
Pulsatile blood flow, increases during __ and decreases during __
Ventricular systole, diastole
Ejection of blood by ventricles into arteries is
Not continous
The most common indirect method of measuring systemic arterial blood pressure is referred to as an
Auscultatory
Characteristics of the continuous capillaries
No holes/clefts, only molecules can diffuse for gas exchange
characteristics of the discontinuous capillaries
not in full contact, large proteins/molecules go through (liver)
characteristics of fenestrated capillaries
small holes in endothelium, small molecules can pass through like ions (for filtration)
What controls blood flow in capillaries, rings of smooth muscle
precapillary sphincters
precapillary sphincters found on what end
arterial end
Precapillary sphincters close capillaries in response to
local (intrinstic factors)
When sphincters relax…
blood flows in
Vasodilation instrinsic factors for precapillary sphincters are
increased CO2 and decreased O2
Vasocontriction instrinsic factors for precapillary sphincters are
endothelin and metabolites
Blood flow is the __ in capillaries because
slowest, has the highest total cross sectional area
Capillaries vs arterioles with blood pressure
Capillaries have the lowest blood pressure and velocity
Starling’s forces describe…
bulk flow (capillary exchange/transport)
From the interstitial space to capillary =
From the capillary to the interstitial space=
absorption, filtration
Bulk flow from filtration across a capillary depends on a balance of ….
hydrostatic and protein/osmotic pressure gradients
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
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
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
What side has a lower BP, venous or arterial
venous
How to mobilize venous return (increase preload…
- Musculoskeletal and respiratory pump
- Venous pressure gradient= need pressure change to move blood
- Venous valves= 1 way valve
- Sympathetics innervates veins through venoconstriction
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
Preload=
EDV
SV=
EDV-ESV
What are baroreceptors?
Stretch receptors, monitor BP in the walls of carotid arteries and aorta
What factors regulate blood flow
intrinsic
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)
What are factors regulate blood pressure
neural, hormones
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)
How do baroreceptors wok?
Respond to BP changes (stretch)–> sends AP
Baroreceptor is what kind of reflex
negative
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
What effectors are dually innervated of the baroreceptor reflex
AV/SA nodes
Blood flow relationship to pressure and resistance
Blood flow proportional to pressure, but inversely proportional to resistance
Hydrostatic pressure is
blood pressure (fluid) + gravity
Effects distribution of blood in CV system
Hydrostatic pressure
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
Blood distribution and hydrostatic pressure are even throughout the body when?
Supine
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)
Neural vs hormonal reflexes
Neural is faster, reacts to change in position
Hormone has longer term effects
