6-Cardiovascular
human heart: how are the pumps? what does each do? how? what about valves?
*The left and right sides of the human heart, like all four chambered hearts, may be thought of as separate pumps.* : The left pump delivers blood to the systemic circuit. The right pump delivers blood to the pulmonary circuit. >>>Atrioventricular valves between the atria and ventricles prevent backflow into the atria when the ventricles CONTRACT. >>>The pulmonary valve and aortic valve prevent backflow into the ventricles when the ventricles RELAX. *so relax is when ventricle relaxes, open to atria, blood flows in *so contract is when ventricle pushes blood travels to pulmonary artery or aorta
any activities that inc metabolism of tissue also inc _______ or _____ in tissue
Any activities that increase metabolism of the tissue also increase blood flow or hyperemia in the tissue.
dec blood flow to tissue, what happens?
Autoregulation art: dec blood flow to tissue, PCCO2 goes up, causes vasodilation of capillary beds
what 3 hormones cause arteriolar constriction?
***epinephrine* ***vasopressin* --antidiuretic hormone (ADH), 2 primary functions are to retain water in the body and to constrict blood vessels. regulates the body's retention of water by acting to increase water reabsorption in the kidney's collecting ducts; increases water permeability of the kidney's collecting duct and distal convoluted tubule by inducing translocation of aquaporin-CD water channels ***angiotensin* --causes vasoconstriction and a subsequent increase in blood pressure. It is part of the renin-angiotensin system, which is a major target for drugs that lower blood pressure. also stimulates the release of aldosterone
how does exercise effect starling's forces?
*As blood flows through the capillary, CO2 diffuses into the plasma and is converted into HCO3-.* remember --inc bicarbonate conc cause osmotic pressure to be higher at venous end of capillary bed, esp during exercise ===so, co2 and hco30 are imp factors that pull water back into the capillaries, along with colloidal osmotic pressure
African lung fish do what? describe
But if PO2 low, come to surface and breathe air; even some are obligate air breathers (must do air in addiotn to gills) Come to surface, gulp air and push thru esophagus to lung When breathe air,t hey often go into mud at bottom of pool of wate rand build mucus and water mud cocoon with a hole at the otp that lets air enter and exhit and ist there until rains blood water again; could be months and even years! One came out of 7 year thing and swam around once in water again
where does blood exchange occur?
Capillaries have a very small diameter, and blood flows through them slowly. in fact, red blood cells must pass through single file! Single! just 1!, layer of endothelial cells (are the capillaries) is where exchange occurs. fluid squeezes out of the spaces bet the cells So high permeability in capillaries is important Also the walls of capillary have regions through which water and small solutes can move, this membrane type is fairly permeable sep with those rivet regions
what's the croc shunting called when underwater?
During diving events however, muscular constriction of the pulmonary artery causes increased pressure in the right ventricle and blood passes from the right ventricle into the aorta and systemic circulation. i.e. the lungs are bypassed - right to left shunt. Shunting of blood has been reported to be as high as 100% in some diving reptiles. Oxygen in lungs is used as a reservoir and intermittent changes in shunting has been observed. It has also been suggested also as a mechanism for thermoregulation and to prevent oxygen loss through the skin.
what's a record of electrical events in cardiac muscle? electrodes placed on diff remote locations, detect heart ap at diff times and register a voltage difference diagnose heart problems what do the letters mean?
EKG electrocardiogram PQRST: p means depolar of atrial muscle q, r, and s together mean the depolar and contraction of ventricles t means relaxation and repolar of ventricles
T/F: All mollusks use an open circulatory system
FALSE CEPHALOPODS DON'T! ___Cephalopods have more arteries and veins and 2 chambered heart, altho 'open' bec arteries and veins usually not connected)
regulation of circulation
Mostly sympathetic is acitng, releasing norepi, but of course the response depends on the receptors Input from sypathetic is chronic firing, all the time, keeping certain level of vasoconstrcition on , more vasoconstriction if more firing of neourson, if dec this firing get vasodilatinon In some skeletal msucles, some sympathetic neurons release acetychloine instead of norepi, which happens during exercise and so vasodilation
effect of slow closing of K+ on pacemaker potential?
These channels are slowly clsoing during pacemaker ponteila as well Slows donw outflux of K+ from outside (builds + charge) which appens wright up to thresohold Sodium enters, ca enters, k outflux is slwoing donw (buildng up K) all hel pbuild + charge in isnde = depolariation Takes long bec upper limt on how soon heart can contact
the plateau of ventricular muscle cell action potential is due to _______________________________________________; as long as ____ channels remain open, the ventricular cells continue to contract. when _________ occurs, we get the repolarization
a sustained opening of voltage-gated Ca2+ channels and delayed opening of K+ channels Ca2+ channels are open when Ca2+ influx STOPS
veins: blood tends to ------ bec .... so veins are called .... WHAT'S Their pressure like? how does blood move thru them (what is used to help this)
accumulate in veins bec they are distensible called CAPACITANCE VESSELS , HIGH CAPACITY TO STORE BLOOD low, very low pressure, and blood movement relies on gravity, vessel squeeizing by skeletal muscle, breathing, and limited smooth muscle contraction
COLLOIDAL OSMOTIC PRESURE
aka oncotic pressure OSMOTIC pressure that draws water into capillaries created by large prot mol in capillary one of starling forces for water balance in capillaries
a normal heartbeat begins with ______ in _____ causing .... the venticles do not do ^that with the atria because there are ______________________________________
an ap in sinoatrial node spreads thru atrial cells, causing them to contract in unison bec there are no gap junctions between the cells of atria and ventricles
*for large arteries to small arteries to arterioles to capillaries to venule to veins, describe:* the total area the mean blood pressure the velcoity
area is low for everything except capillaries (very high for) mean blood pressure highest in arteries, drops in capillaries, lowest in veins/venules velocity dec from being high in arteries to low in capillaries then inc in veins Vein(smaller veins are known as venules.) -Artery(smaller arteries are known as arterioles.) -Capillary(smallest of ALL blood transporting tubules.)
what side of heart has more smooth muscle and is where changes in resistance mainly occur?
arterial side
smooth muscle cells, esp in ______ & _____ (called what??), but also in veins and venules regulate the vessel diameters via vasodilation/constriction. SMOOTH muscle cells are under what control?
arteries & arterioles aka resistance vessels neuronal and hormonal control
arteries vs veins: form follows function
arteries: elastin, smoth muscle, need to handle high pressures veins: low pressure so some have valves to prevent backflow of blood
capillary beds: are between ____ they ___________ bet ___ & ___ thru their thin walls the high pressure in arteries is affected HOW? by the huge #s of arteriole and huger # of capillaries? the total cross sectional area of the capillary beds is ______ than any of the other vessels; thus ______ is _____ to a ____ level.
arterioles and venules exchange materials bet blood and tissue this high pressure is DISSIPATED! bec of the HUGE CROSS SECTIONAL AREA OF CAPILLARIES, the huge pressure from arteries is dissipated by the capillaries: pressure is reduced to very low level!
the cardiac cycle can also be felt in ______, the surge of blood during systole
artery pulsation
what lil' workers keep solutes out of the brain?
astrocytes
how has giraffe handled returning venous blood?
aterial side has to pump blood from heart to head, need that much extra pressure Their heart has to do tons of work to et blood to brain, needs gooood pressure When he takes a drink, if barorec don't notice the change in pressure, he would blow his brains out bec the pressure in head skyrockets! Msut affect this in heart When he raises head back up, the barorec have to kick in When you re asleep and stand up rast, this is what's happening; barorec pick up change in pressure right away, changing sys
heart attack/stroke is result often of ____ this occurs by: when smooth internal lining of arteries is damaged, ________ called ____ form @ damaged sites (needa bandaid realllll bad) --_____ and _______/______ _____ invite fibrous connective tissue and calcium deposits ---->so, the artery wall is less elastic, and the ___ narrows the lumen of artery ______ stick in plaque and form______, further blocking the artery
atherosclerosis (hardening of arteries) deposits aka plaque -swelling & lipid/cholesterol deposition plaque BLOOD PLATELETS form blood clots (thrombus) even if not totally obscured, you DEC BLOOD FLOW
at end of diastole, the _____ ____. the sound of cardiac cycle (lub-dup) are from
atria contract (1st actually), so atria contract, then ventricles relax, repeat... (so after the ventricles relax, the atria contract) ---caused by the closure of heart valves--cool!
what controls heart rate by ______________ at which _____ gradually ______? ________ and ______ from the _____________ & ________ nerve endings ________ and _______ the rate, respectively
autonomic nervous system influencing the rate at which pacemaker cells gradually depolarize *acetylcholine from parasympathetic SLOWS HR norepinephrine from sympathetic INCREASES HR*
during walking/running, the skeletal muscles in legs act as _____ and return blood to the heart from the venis.
auxiliary vascular pumps
most of the volume at any given time for blood is in
blood capillaries
how does breathing help return venous blood to heart?
breathing dec pressure in thoracic cavity, which pulls blood and lymph toward chest
but why does edema and why do birds also change the starling's forces idea?
but, edema does not occur during hard exercise dose not occur in birds (which have higher arteriole pressure and lower colloidal osmotic pressure than mammals) *As blood flows through the capillary, CO2 diffuses into the plasma and is converted into HCO3-.* remember --inc bicarbonate conc cause osmotic pressure to be higher at venous end of capillary bed, esp during exercise ===so, co2 and hco30 are imp factors that pull water back into the capillaries, along with colloidal osmotic pressure
which animals can control their blood flow and which cannot?
cannot: open circulatory system animals and fish can: amphibians, reptiles, mammals, etc.
___________ in the aorta and carotid arteries also stimulate the medulla regulatory system. The chemoreceptors signal when ______ of the blood falls drastically. Also, sensitive to ____ levels (pH). ___________ may cause the medulla to signal an increase in heart rate and blood pressure.
chemoreceptors O2 content co2 emotions and anticipation
what signals high PCO2 in blood?
chemoreceptors in medulla (diff fro those I aorta & carotid arteries that detect when blood PO2 falls)
what's activated when blood PO2 falls? where?
chemoreceptors on aorta and carotid arteries; think: chem notices when u falling
backpressure is due to
contractions of atria, contractions of muscles, and sometimes gravity
_____ cause heart murmurs, whooshing sounds following the lub
defective valves
fetal lungs...
do not contain air In children and adults, blood picks up oxygen in the lungs. But in a fetus, the blood that enters the heart already contains oxygen, supplied from the mother by the placenta. Only a small amount of blood goes through the lungs (which do not contain air). The rest of the blood bypasses the lungs through two structures: the foramen ovale, a hole between the right and left atria, and the ductus arteriosus, a blood vessel that connects the pulmonary artery and the aorta. Normally, these two structures close soon after birth.
what's ca doing that's imp in muscle contraction?
double job: bringing + ness into the cell helps w depolar also, bind to prot in muscle cells (troponin prot) that singal actin and myosin to do contraction!
patent ductus arteriosus pda
ductus arteriosus didn't close
large artery walls are _________ to ___________ and ___________ by ___________
elastic handle high pressures, squeeze blood along lumens by elastic rebound
AT REST, SINOATRIAL PACEMAKER cells are more permeable to ____ ions than are neurons or other muscule cells
Na+
remember that with capillary beds vs arteries: in reg times:
Notice: artery leading to venule: blood doesn't have to go thru capillary bed; remember in reg times when PO2 comes back to areterial side and 25% of hemoglobin is released/passed thru body Means if exercise left rm, local contol opens capillaries on that side
acetylcholine released by ...
PARASYMPATHETIC think: Es simpatico PARA me ACE DIS EXAM! OR: AP SYMP
if fire vagus nerve, we
SLOW HR LIKE IF WE ADDED ACH
if HR is too fast, ______ becomes low, and _________ .....
SV stroke volume becomes super low (*sv=how much blood is pumped by 1 ventricle in systole) therefore little blood gets pumped and lots of E is wasted
norepinephrine released by...
SYMPATHETIC think: NO one REPS that EPRON like the PLAIN, SIMPLE EFRON OR NOSYMPATHY #rideordie
heart of both mammals and birds is... and symmetry wise, ...
The heart of both mammals and birds is a double pump, powering two systems of vessels with different characteristics. The left ventricle has a thicker layer of muscle around it, a necessary adaptation for powering its beat against the high resistance of the extensive systemic circulation throughout the body. The right ventricle has a thinner wall, consistent with its role in pumping blood to the lungs against a much lower resistance. both asymmetrical but in opposite ways
cardiac muscle cells are in ______ w one another through ________________ this allows ________ for effective blood pumping some cardiac muscle cells initiate ap w/out nerv stimulation: ____ the primary pacemaker of the mammal heart is the _________________ located at the juncture of the ______________________________ the resting potential of these cells gets _________ until they reach the threshold for initiating an ap
electrical contract gap junctions coordinated contraction pacekamer cells sinoatrial node juncture of superior vena cava and right atrium less negative aka more positive
capillary walls are a single layer of _____ cells and have fine holes aka ________. many small mol leak thru, but larger proteins are held back. ______ in capillary beds is a result of 2 opposing forces aka _________
endothelial fenestrations water balance; Starling's forces of BLOOD PRESSURE & OSMOTIC PRESSURE
t/f: there is smooth muscle in capillary beds, and a little elastin
false! no smooth tissue, and no elastin, in capillary beds
atrial septal defect asd
foramen ovale didn't close
compare the pressure in systemic and pulmonary in crocs.
higher in systemic --has longer distance to push blood thru, esp to push through the tiny capillary bits lower in pulmonary --short distance of lungs to push blood through doesn't req are much pressure --why left ventricle is more muscular
if you had higher pressure in right ventricle of croc heart, ....
higher pressure on right would not be better bec blood pressure squeezes out of interstitial somewhat and if we have it pushing stronger in right we'd have water in lungs!!!!
what problem do athletes have, like Reggie Lewis?
highly trained athletes: a small arrhythmia, but bec of the strenuous exercise, if it coincides with an arythemia, then fatal
T/F: amphibians have higher pressure in left atrium of heart.
i think FALSE! note: cannot have diff pressure on r and l side of heart bec 2-chambered
relation bet blood pressure and resistance
if blood pressure drops, than slower flow so higher resistance (be careful with this!!!)
relationship bet blood pressure and urine output: falls....
if falling bp: -kidneys rel renin, which activates angiotensin, which constricts vessels and stim thirst = BP RISES if rising bp: then need to
so, if I increased the diameter of a vessel, the blood flow would ____ bec
inc diameter = inc radius= decrease resistance (remember resistance varies inversely with radius ^4) v = chg pressure / resistance smaller denominator means INC BLOOD VELOCITY BY INC DIAMETER OF VESSEL
how does ADH (ANTIDIURETIC HORMONE) (vasopressin) inc blood pressure?
it opens aquaporins in kidneys, raises blood volume and pressure, cause more reabs of water, and stim constriction
if I wanted to stimulate something to make epinephrine, what would I stimulate? also, describe the presynaptic vs postsynaptic cells' types of neurotransmitters used
kidney / adrenal gland ................*Sympathetic..........Parasympathetic* Preganglia Acetylcholine .........Acetylcholine Postgalgia Norepinephrine.........Acetylcholine
which ventricle is more muscular?
left bec there is higher resistance for the systemic circuit than pulmonary circuit
precapillary sphincters open in response to...
lo O2, high CO2 low pH cytokines
local controls of pre capillary sphincters means... most capillary beds are by default ____ but ___ when needed if all our capillary beds opened right now, .... because....
local control means if PCO2 is high and PO2 is low, the sphincters open up *without any input from brain* or other this is LOCAL CONTORL Most of capillary beds are closed and oepn when needed PCO2 inc, open capillary beds =we'd pass out bec all the blood volume would inc and so pressure would decrease
net ____ of water across capillary what's going on also on venule side that would make osmotic ptoentiallly higher than arterial and = tendency to revoer more water on venule?
loss co2 being converted to bicarbonate on venous side
lymph nodes: function
lymph nodes are major sites of lympohtocyte prod nodes are also filters that have phagocytic cells to remove microbes
mammals alveolar surface
mammals: alveolar surf is huge relative to lungs and we have huge amounts of alveoli in our lungs' bronchi! packed full! chock! body more sensitive to co2 but go hand in hand, high co2 means low O2 high altitude: low O2 an low CO2 and wacked out for us this combo is problematic in mammals and humans, causes vasoconstriction to brain amphibians (not complete but more complete)
where is the cardiovascular center?
medulla
The cardiovascular centers in the _____ of the brain stem control heart (cardiac output) rate and blood vessel constriction through the The medulla is influenced by many inputs from _____ & _____ : _________ (baroreceptors) in the aorta and carotid artery provide info about ____________. When atria are getting too much venous return and/or blood pressure is hi, they release a hormone called _____________, which stimulates
medulla; autonomic nervous system. sympathetic and parasympathetic areas. Stretch receptors ; information about blood pressure. --- a hormone called atrial *natriuretic factor*, which stimulates the kidney to excrete sodium and water, resulting in a reduced blood volume and pressure.
how is the ventricle acting in reptiles?
the ventricle is partly divided by a septum that directs oxy blood to body and deoxy blood to the lungs
edema: what's it mean? what does it support
tissue swelling or inflammation in tissues w injury or allergies support model of starling's forces, because: ◦A number of processes can UPSET the finely balanced fluid filtration of capillary beds by changing the key variables of the Starling Forces. In most cases *****this results in excessive water filtration out of the capillaries*. (***AND into tissues)
crocodilians: have ___ heart with what makeup? (aortas and stuff)
true, 4-chambered heart, 2 aortas (one from each ventricle), with a channel connecting the 2 aortas
remember, resistance
varies inversely to radius ^4
velocity of blood flow
velocity of flow = change in pressure / resistance as diameter changes, resistance to flow varies inversely , allowing blood to be distributed to diff tissues.
If artery is especially obscured in the ______, then______
ventricle muscle needs extra extra oxygen and cannot et it, you feel super out of breath bec heart cannot function well and if blocked completely it's bad news
cardiac output what's the formula?
volume of blood pumped by ONE SIDE (doesn't matter which) of the heart per unit time (4 chambered heart) CO= heart rate x stroke volume stroke volume = volume of blood pumped by one of ventricles in 1 systole (contraction of ventricles)
Starling's forces:
water balance in capillary beds is a result of these 2 *blood pressure squeezes water and small solutes out of the capillaries; osmotic pressure created by the large protein molecules in the capillary, COLLOIDAL OSMOTIC PRESSURE (PART of osmotic pressure due to hi MW solutes, aka oncotic pressure) draws water into capillary. usually a net loss of water out of the vascular system, necessitating the lymphatic system
foramen ovale
when blood enters right atrium (partly oxygentated from mom's blood from inferior vena cava) it passes thru interatrial opening bet right and left atria. by doing this, the majority of the blood bypasses the lungs/pulmonary circuit, going out the aorta instead very directly.
pacemaker potential
when not adding anything
atria contract when...
when they fill with enough blood to inc pressure and pop a valve open
right atrium gets blood from.... from right atrium, blood goes to .... which sends blood thru ..... to .... _____ then retrun oxygenate blood to ...... from here, blood goes to ..... this sends blood thru ..... to the .... and .... .... blood returns to the .... via .....
- superior and inferior vena cavas. From the right atrium, blood goes to the right ventricle. The right ventricle sends blood through the pulmonary artery to the lung. Pulmonary veins return oxygenated blood to the left atrium. From the left atrium, blood goes to the left ventricle. The left ventricle sends blood through the aorta to the body and the capillary beds. Blood returns to the right atrium via veins.
African lungfish: *gill arches *heart's atria *blood flow-separated?
---The posterior pair of modified gill arches directs some of the blood coming from the heart to the LUNG, and a new vessel carries oxygenated blood from the lung back to the heart. --THE ANTERIOR gill arches take THE NOW OXY blood from lungs from posterior, and output this now oxy blood to aorta --the 3 central gill arches take blood (when fish is in water) and oxygenate it!!!!! --the heart has a partly divided atrium; the left side receives oxygenated blood from the lung, the right side receives deoxygenated blood from the body. The blood streams stay separate as they go through the ventricle. Oxygenated blood goes mostly to the body; deoxygenated blood goes to the lung.
LOCAL control of circulation: when arteriole blood flows into cap. bed, how does smooth muscle react and by? low O2, high Co2 levels, = high levels of metabolism cause .... which does what.... what is this response called?
---smooth muscle in the arteriole may constrict or relax by means of precapillary sphincters. -->Low O2 and high CO2 levels cause the smooth muscle to relax and increase flow in the capillary bed (wants to exchange more) = inc blood flow ===This brings in more O2 =====& takes away CO2. the response is called hyperemia (excess blood).
posterior gill arches
the nonfunctional gills, lack lamellae where gas exchange normally occurs, on the back/bottom in flow diagram, through which blood travels when fish are in air to go to lungs, be oxygenated, then pass thru anterior on way to systemic
at initiation of ap, what happens? at repol of ap, what happens?
(A) The three phases of the action potential of ventricular muscle fibers are due to the opening and closing of voltage-gated channels. (B) At the initiation of the action potential, voltage-gated Na+ channels open rapidly but briefly. At the same time, but more slowly, K+ channels are closing and Ca2+ channels are opening. The open Ca2+ channels sustain the depolarization. Repolarization occurs when the Ca2+ channels close, and the slow opening of the K+ channels also contribute to the repolarization. *Ca++ influx serves to (1) provide positive charge to cell, AND (2) to bind to troponin thereby allowing contraction of the muscle cell.*
how does the whole breathing system of African lungfish work?
*The posterior pair of modified gill arches directs some of the blood coming from the heart to the lung, and a new vessel carries oxygenated blood from the lung back to the heart. The posterior pair of arches have non-functional gills (exchange CO2, but not O2) . *Blood is directed appropriately depending on whether the fish is air or water breathing.* The heart has a partly divided atrium; the left side receives oxygenated blood from the lung, the right side receives deoxygenated blood from the body. The blood streams stay separate as they go through the ventricle. Oxygenated blood goes mostly to the body; deoxygenated blood goes to the lung.
if these openings failed to close after birth, ....
*VALVE DEFECTS* develop higher pressure on left side so get back flow of oxygenated blood into deoxygenated bec of higher pressure pushing that valve pacemaker creates new channels w channels *Either the flow of blood gets re-routed (shunted) or a defective heart valve or a blood vessel blocks the flow of blood.* --Shunting can cause oxygen-poor blood to mix with oxygen-rich blood that is pumped to the body tissues (right-to-left shunt). The more oxygen-poor blood (which is blue) that flows to the body, the bluer the body appears. Many heart defects are characterized by a bluish discoloration (cyanosis) indicates that not enough oxygen-rich blood is reaching the tissues where it is needed. ---->>>Shunting can also mix oxygen-rich blood, which is pumped under high pressures, with oxygen-poor blood being pumped through the pulmonary artery to the lungs (left-to-right shunt). *Shunting makes the circulation inefficient and increases the pressure in the pulmonary artery. The high pressure damages the pulmonary artery and lungs.* The shunt also eventually leads to an insufficient amount of blood being pumped to the body (heart failure). -------In heart failure, blood also backs up, often in the lungs. Heart failure can also develop when the heart pumps too weakly (for example, when a baby is born with a weak heart muscle) or when blood is blocked from flowing to the baby's body. Blockages may develop in the valves of the heart or in the blood vessels leading away from the heart. Blood may be impeded from flowing to the lungs because of narrowing of the pulmonary valve (pulmonary valve stenosis) or narrowing within the pulmonary artery itself (pulmonary artery stenosis). Blood may be impeded from flowing through the aorta to the body because of narrowing of the aortic valve (aortic valve stenosis) or blockage within the aorta itself (coarctation of the aorta).
what's the design of circulatory systems in sponges and cnidarian?
*acoelomates--no true body cavity; 'gastrovascular circulation' include flatworms and tapeworms, exhibit bilateral symmetry and have no body cavity between the gut and the epidermis. *cnidarian--coelenterates (aneno mes, jellyfish) -diffusive gas exchange via epidermal gastrodermal cells -grow up to 2m in diameter; anemomes up to many cm *large anenomes have internal foldso f gastrodermic mesenteries *porifera (sponges) gas diffusion, semi-random nutrient diffusion, no true body cavity tube-looking organims
amphibians: what happens when air breathing?
*air breathing: mix of blood in ventricle is MINIMIZED by PARTIAL SEPARATION: DEOXY BLOOD is directed to pulmonary circuit; OXY BLOOD is directed to aorta from left ventricle* *this partial separation of pulmonary and systemic circulation allows delivery of blood in aorta and tissues at higher pressure than in "normal" (non-air breathing) fish* note there's a just a bit of mixed blood in between atria, for what goes to lungs to be oxy, and for what leaves left atrium to oxygenate tissues via aorta
what's activated when bp rises? where's it activated?
*baroreceptors* in aorta & carotid artery feedback to medullary cardiovascular center think: baro when rising
open circulatory system vs closed: drawing which is more efficient and WHY???
*less efficient movement in open system BEC LOWER PRESSURE* insect: tubular heart, peristaltic wave of contraction, moves blood forward; accessory hearts mollusk: artery foot, stomach, heart, cgills, foot, vein from foot going to heart
lymphatic system: function? how?
*moves tissue INTERSTITIAL FLUID that accumulates outside of capillaries* Pick up interstitial fluid Small -->coalesce-->dump into veins, dump lymph into veins LYMPH moves small -->larger vessels and empties into THORACIC DUCTS, empty N2 large neck veins lymph moved thru vessel by skeletal muscle contractions (but lower ertebraets excelpt fish have lymph hearts) and the vellses have mooth muscle and one-way vales to PREVENT BACKFLOW. Lymphatic capillaries are blind-ended but highly permeable. They drain excess tissue fluid into lymph ducts. Lymph passes through lymph nodes and is returned by way of the lymph ducts to the venous blood
for Non-crocodilians (turtles, aquatic snakes, some aquatic lizards), what occurs during a breath? during a dive?
- During a breath, resistance to flow through the pulmonary circulation is low (because of vasodilation in pulmonary vessels), blood flow is high. When diving, there is an increase in resistance in pulmonary circulation (due to vasoconstriction of pulmonary vessels; resistance varies inversely with radius4), and a reduction in cardiac output associated with bradycardia (low heart rate).
why haven't amphibians evolved a 4 chambered heart?
--because they go in water a lot; when normally breathes air, low resistance and so the pressure on right ventricle is not that high bec have low resistance; but w 4 chambers, their heart would be high pressure which would put excessive pressure on ventricle when underwater but when water breathing, Resistance inc largely (vasoconstrict) when diamter decreases So when in water and not breahting they vasocontstrict ot lung circulation and get back pressure that pushes blood over to the left sid eand on thru the sytemic ciculation When we hold breath, the change in diatmer of blood vessels occurs So when dive, don't spend much energy pushing blood thru lungs Also many have regions of body with vasculationzation on body so body surface is thin and gcan take up oxygen and give off co2 thru skin (not shown here)
starling's forces: when blood pressure is greater than osmotic pressure, _________ when blood pressure is less than osmotic pressure, _____ how does this change over capillary bed?
--fluid leaves capillaries --fluid returns to capillaries *over capillary bed: higher blood pressure on arterial side than on venous side of capillary*
closed circulatory system: does what? how does the blood move? what organisms have this? how does it work?
--keeps blood and interstitial fluid separate -blood moves by 1+ muscular hearts & branching network of vessels (vascular systesm) -us! earthworms! --->earthworms: the large dorsal & ventral vessels are connected by 5 vessels actin' as hearts (give fluid a push) (dorsal vessel is pulsatile); direction of flow CONTROLLED BY 1-WAY VALVES. see pic^^^
larger animals, with many cell layers, need .....
--larger animals with many cell layers need *extracellular tissue fluids to carry materials to and from cells.*
which animals don't have circulatory systems? how does this work? how do they maximize exchange?
--some simple, usually small, aquatic animals --in these small animals, nutrients, gases, and wastes DIFFUSE between the cells and environment and a circulatory system aint needed. -some have flat body or highly-branched GASTROVASCULAR CAIVTY (GUT+CIRCULATORY SYS) for max SA for exchange. remember the leaf like, sponge, an frog with feathers looking animals?
amphibian heart setup
-3 chambered hearts with 1 ventricle, 2 atria --->1 atrium gets deoxy blood from body; other gets oxygenated blood from lungs
vertebrate circulatory systems
-closed sys -hearts with 2+ chambers -valves prevent backflow when HEART CONTRACTS -separate circulations ALLOW differential pressures in pulmonary and systemic (higher) circulations --2 circuits: pulmonary where blood goes thru capilary beds, small vessels takes lots of energy from right ventricle thru capillary beds in lungs is huge drop in pressure, comes back to left ventricle (heavily muscle bec has to do more work) which has to push lots of blood that is lower pressure thru arteries
what's cool about African lungfish?
-evolved a primitive lung from an outpocketing of the gut= lets them BREATHE AIR WHEN WATER IS ANOXIC/DRIES UP
blood brain barrier: what can and cannot cross
-lipid-solube stuff and small mol can pass easily thru capillary walls in most tissues, but CAPILLARIES OF BRAIN DO NOT HAVE FENESTRATIONS. NONE. -->FEW THINGS, besides lipid-soluble mol like alchohol can pass thru brain capillaires.
measuring blood pressure
1 cuff inflated beyond the point that shuts off all blood flow 2 pressure in cuff lowers until sound of a pulsing blood flow thru CONSTRICTION ARTERY is heard; here, cuff pressure is just below the PEAK SYSTOLIC PRESSURE In artery 3 pressure is lowered until sounds continuous; here, the cuff is just below the diastolic pressure in artery
venule
1.a very small vein, especially one collecting blood from the capillaries
Turtles, snakes, and lizards have _____ and ____ that is ______ divided by a septum. Although actually 3-chambered, the heart is functionally____-chambered when the animal is breathing. When the animal is not breathing (resting, diving, etc.), this setup allows _________ of blood vessels in the lung circuit and _________ of blood through ______to the _______circuit.
2 aortas, 1 ventricle incompletely divided functionally FOUR CHAMBERED CONSTRICTION SHUNTING BOTH AORTAS SYSTEMIC
lymphatic systems: if obstructed by filariad parasitse: lymph volume = ___ L/day blood volume= ____ L
2-4 L/day returned; 3.5-4L of blood If that doesn't happen: Worms are blocoking lymph vessels, lymph cannot get back out so the lymph builds up Return of lymph is reallly important
how long do contractions of ventricle muscle fibers last? how are ventricular muscle cell ap initiated? but, unlike neurons and skeletal muscle, .....?
300 ms ventricular muscle cell action potentials are initiated (depolarization) by the opening of voltage-gated sodium channels and closure of K+ channels ventricular muscle cells stay depolarized for a long time
BIRDS & MAMMALS: HEART ADVANTAGES
4 CHAMBERED, completely separate the pulmonary and systemic circuits advantages are:____ --oxy and deoxy cannot mix --gas exchange is maximized bec lungs get only blood w low O2 and high CO2 --*separate circuits CAN operate AT DIFFERENT PRESSURES* =great! *--->higher on systemic side (better perfusion of muscles)* *lower on pulmonary side (less resistance, fewer capillary beds to push blood thru), less pressure is needed to perfuse lungs (high pressure can cause pulmonary edema!)*
what is a circulatory system composed of? what are its functions? -deliver ________ -remove _______ -vehicle for delivery of ______ --provides pressure for __________ by ______ --circulates _______ ---_____ control ----hydraulic force for limb extension, wing expansion, etc.
A circulatory (cardiovascular) system is composed of a *pump (heart), fluid (blood), and conduits (blood vessels).* The functions of the CV system are to: - deliver O2 and nutrients (glucose, fatty acids, amino acids, etc.) to the tissues. - remove CO2, metabolites, and metabolic wastes from the tissues. - vehicle for delivery of hormones - provide pressure for filtration of blood by kidney. - circulate specialized immune cells - temperature control
pros of closed systems! and how these are helpful!
ADVANTAGES :) -*HIGHER blood pressure, higher flow ---->so nutrient deliver and waste removal, gas exchange, more RAPID --CAN DIRECT BLOOD to specific tissue, can VARY FLOW as needed (like for temp control via peripheral vasoconstriction &dilation) --cellular elements & mol that r HELPFUL IN TRANSPORT can be kept within the vessels* *generally support higher metabolisms; insects are exception bec they do NOT RELY on their circulatory systems for gas exchange, they use tracheal system, yet have HUGE METABOLISMS (RAISE IT 100 FOLD)*
consequences of defects (foramen ovale and/or ductus arteriosus not closing) are:
ATRIAL SEPTAL DEFECT ASD PATENT DUCTUS ARTERIOSUS PDA
amphibians: is there an advantage to their less efficient circulation system???
Amphibians have a three-chambered heart that has two atria and one ventricle rather than the two-chambered heart of fish (figure b). The two atria receive blood from the two different circuits (the lungs and the systems). There is some mixing of the blood in the heart's ventricle, which reduces the efficiency of oxygenation. ___*The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body.* The mixing is mitigated by a ridge within the ventricle that diverts oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit where gas exchange occurs in the lungs and through the skin. For this reason, amphibians are often described as having double circulation.
fetal heart: how does blood travel? ___ of blood entering the ______ (how much oxygenated?) passes thru ____________, then the _____, to the ______, then _____ and finally to aorta. most of the blood that does enter the right ventricle ___________ lung circulation by ________.
Blood oxygenated in placenta, not lungs. ~ 1/3 of blood entering the right atrium (partly oxygenated, returning from inferior vena cava) passes through an inter-atrial opening, the foramen ovale, to the left atrium, on to left ventricle and to aorta. Majority of blood that does enter the right ventricle by-passes the lung circulation via the ductus arteriosus.
describe how the OPEN circulatory system of an insect works.
Body fluids enter through one way valved ostia which are openings situated along the length of the combined aorta and heart organ. *Pumping of the hemolymph occurs by waves of peristaltic contraction, originating at the body's posterior end, pumping forwards into the dorsal vessel, out via the aorta and then into the head where it flows out* into the haemocoel.[6][7] The hemolymph is circulated to the appendages *unidirectionally with the aid of muscular pumps or accessory pulsatile organs which are usually found at the base of the antennae or wings* and sometimes in the legs.[7] Pumping rate accelerates due to periods of increased activity.[4] Movement of hemolymph is particularly important for thermoregulation
Cardiogenic pulmonary edema
Cardiogenic pulmonary edema is a type of pulmonary edema caused by increased pressures in the heart. This condition usually occurs when the diseased or overworked left ventricle isn't able to pump out enough of the blood it receives from your lungs (congestive heart failure). As a result, pressure increases inside the left atrium and then in the veins and capillaries in your lungs, causing fluid to be pushed through the capillary walls into the air sacs. can result from too much pressure on pulmonary side *ALVEOLI ARE FILLED WITH FLUID NOT AIR* P*ulmonary edema is a condition in which the lungs fill with fluid. When this occurs, the body struggles to get enough oxygen.* The most common cause of pulmonary edema is congestive heart failure. Heart failure is characterized by the heart no longer being able to pump blood properly throughout the body.
controlling blood pressure: a drop in arterial pressure ______________, resulting in ________________. this change in extracellular environment stimulates ________ opening of ________. fall in bp: prevented by ___________________, including the release of ______________ that does what in arteries and stimulates maintenance of _____ & ______.
Control of Blood Pressure through Local and Systemic Mechanisms: A drop in arterial pressure reduces blood flow to tissues, resulting in local accumulation of metabolic wastes. This change in the extracellular environment stimulates autoregulatory opening of the arteries. A fall in central blood pressure is prevented by negative feedback mechanisms (including the release of antidiuretic hormone, ADH) that constrict arteries in less essential tissues and stimulate maintenance of blood volume and blood pressure.
t/f: arteries > veins
DEPENDS generally veins are larger in volume, but arteries have thicker walls to push blood in high pressure situations
GIRAFFES
Giraffes, for example, maintain the highest blood pressure of any extant animal, which gives important insight into medical importance of hypertension. For blood to reach the giraffes head whilst standing, the systolic blood pressure reaches around 250 mmHg (healthy human systolic blood pressure would be less than half this). This presents a serious problem when the giraffe bends its neck down to drink. This action would be predicted to rapidly increase cranial blood pressure, causing a fatal, instantaneous haemorrhage. To avoid this problem, the jugular vein expands and acts as a volume reservoir (Brondum et al., 2009). Simultaneously, cerebrospinal fluid rushes to the head. *This causes an increase in pressure that acts to reduce the pressure difference between outside and inside the blood vessels, thus preventing the vessels from rupturing.*
when a croc is breathing...
HIGHER PRESSURE in the left ventricle and aorta is communicated to channel -->this stops right-ventricle blood from entering aorta and instead goes to pulmonary circuit since OF COURSE YOU'D WANT TO oxygenate blood if you HAVE AIR (oxygen)?
what's the frank-starling law?
If a greater volume of blood is returned to the heart, which stretches the cardiac muscle cells, the heart contracts more forcefully. This is known as the Frank-Starling law. (The strength of the muscle contraction is proportional to the initial length of the muscle fibers.)
coronary heart disease: what is it? A thrombus here (blood platelets forming clots) (coronary thrombosis) can block an artery, causing _______________. If part of the thrombus breaks away (_______), lodges in vessel in brain, and blocks blood flow, ___ may occur.
If the coronary arteries are affected, blood supply to the heart decreases. *A thrombus here (coronary thrombosis) can block an artery, causing a heart attack (myocardial infarction, or MI).* If part of the thrombus breaks away (an embolism), lodges in a vessel in the brain, and blocks blood flow, stroke may occur. These blocks can happe in lung circulation or anywhere
what determines blood flow in reptiles mainly?
In reptiles with a three chambered heart, vascular resistances determine the preferential route of blood flow
so, if you look at pacemaker cells in petri dish and add ach and ne, what would a graph look like for membrane pot vs time?
Isolated pacemaker cells continue firing action potentials in a culture dish. Neurotransmitter signals from the two divisions of the autonomic nervous system speed up and slow down the rate at which the pacemaker membrane potential drifts upward, thereby controlling the rate at which pacemaker cells fire action potentials. Black: normal pacemaker firing Add norepi onto pacemaker, then you get (red line) speeds up pacemaker poenteila reaching threshold faster, speeds up the heart rate Vs: acetychline in blue line, (add ace. Or fire the things that release it) it slow the rate of pacemaker firing
pacemaker cells
Pacemaker are modified muscle cells Other pacemakers are in various spots, another imp one is *atrioventicluar node at junction of right atrium and left ventricle;* SINOATRIAL NODE is faster so sets the tone, way more than the AV; Sa node fires action potential, all muscle cells have gap junctions so electrically connected and ap jumps from cell to cell thru atria Ap cause muscle to contract causing systolic; direction connections bet sa and av shown in 2nd pic *Pacemaker cells in the sinoatrial node initiate the heartbeat by firing action potentials that spread through the electrically coupled atrial muscle. The atrial action potential eventually spreads to the atrioventricular node which, with a delay, conducts it through the bundle of His and Purkinje fibers to the cells of the ventricles. *
REPTILES: what kind of heart do they have? what's unique about repiles' breathing?
Reptilian (except crocodilian) hearts have --*TWO* atria and a ventricle that is partially divided, ~~~~so mixing of oxygenated and deoxygenated blood is minimized. Crocodilians have an actual four chambered heart. Reptiles have a large range of metabolic needs, from very active states to resting states with very low metabolism. Also, some routinely dive. *This range of demands means that they do not have to breathe continuously.* SO: The lung circuit can be bypassed when they are not breathing. (Note that they have two aortas.) in amphibians, the surface area doing gas exchange is alveoli*;_but in replies the alveoli are on outside PLUS INTERNAL SEPTUM that makes wayyy better! *reptile has greater surface area for gas exchange*
T/F: reptiles can control their blood flow.
TRUE! Lizards, snakes and turtles have a three chambered heart with two atria and one partially divided ventricle. There is a well developed double circulation because under normal circumstances there is little mixing of blood in the ventricle. These reptiles do have the ability to alter their circulation. *If pulmonary resistance is increased, systemic venous return will not all flow into pulmonary artery. Some blood will be pumped primarily into the aorta on ventricular contraction. This is termed the right-to-left shunt. i.e. the lungs are bypassed. Right-to-left shunt is used by diving reptiles and by others during periods of apnea. Similarly, if resistance is low in the pulmonary circulation, a left-to-right shunt takes place.*
shunting blood: who can do it? how does it work? help?
The non-avian reptiles also give insight into the importance of ventricular septation (i.e. whether the ventricle is divided or undivided). This is particularly important in respect to pressure separation: the ability to pump blood at different pressures in the systemic and pulmonary circulations. Pressure separation allows blood to be pumped at high pressure around the body, allowing for an increased oxygen supply, whilst keeping pulmonary pressure low, facilitating a thinner, and more efficient, blood gas barrier. Turtles, along with most snakes and lizards, cannot separate these pressures. Crocodiles have a ventricular septum so can pressure separate, as in mammals and birds. However, pythons and varanid lizards have an extraordinary ability to functionally pressure separate in the undivided ventricle. This occurs because two incomplete septae, the muscular ridge and the bulbuslamelle, meet during systole, thus functionally dividing the heart (Jensen et al., 2010). This ability may be crucial for varanid lizards particularly, which are renowned for their high aerobic performance.
cardiac cycle
The rhythmic contraction (systole) and relaxation (diastole) of the ventricles is called the cardiac cycle. The representation below shows pressure and volume changes during the cardiac cycle for the left ventricle only. Basically: shows pressure in ventricle and aorta right atrium contracts, then the ventricles contract, then blood pumped out of ventricles and into aorta and pulmonary artery; then ventricles relax, pressure in ventricles falls at end of systole, and since greater pressure in aorta and pulmonary artery, the aortic and pulmonary valves slam shut finally the ventricles fill w blood.
reptiles vs other: respiration
Unlike lungfishes and amphibians, reptiles depend entirely on their lungs for respiration. Gills and skin do not provide additional sources of oxygen
amphibians: WHEN underwater? what happens, and how does this affect the blood flow, system, etc.?
most CANNOT BREATHE UNDEREWATER so they do what we do when we hold breath (vasoconstrict) In some amphibians, when under water, *hi resistance due to vasoconstriction in the pulmonary circulation results in increased blood pressure in the right side of the ventricle. This shunts blood to the left side, and consequently most of the blood bypasses the pulmonary circulation and goes directly to the systemic circulation.* This is OK since the animal isn't breathing. -Also, many amphibians can exchange gases across certain areas of their skin when under water. (Frog wintering at the bottom) BELLO IN THROAT of amphibians not that efficient, reptiles' ribs help ventilate push air in and out like a hole in a balloon, not that great *surface area doing gas exchange is alveoli* __but in replies the alveoli are on outside PLUS INTERNAL SEPTUM that makes wayyy better!
circulatory system of fish
most fish: 2 chambers in heart --thin atrium received blood, super muscly ventricle pumps blood *blood pumped to gills (capillary beds) for gas exchange, then thru dorsal aorta to rest of body SO, BLOOD PRESSURE IS LOW in DORSAL AORTA, bec although the fish heart has 2 chambers, they are not separated into separate circulations (like mammalian heart). Therefore, a lo pressure systemic circulation results (from hi resistance across the narrow gill capillaries).and the systemic circulation ---because the narrow gill capillaires dissipate flow force (fish do okaaay, tho) blood collects in veins after PASSING SYSTEMIC CAPILLARY BEDS; later return to atrium
ductus arteriosus
most of the blood that does enter the right ventricle (instead of going to left atrium bia foramen ovale) bypases lung circulation by going instead to aorta
heart attack is called prevention:
myocardial infarcation (MI) The best approach to reducing heart disease is prevention. Risk factors include high-fat/high-cholesterol diets, smoking, a sedentary life style, and obesity.
net forces in venule and arteriole ends of capillary?
net venule: -9 inward osmotic pressure > blood pressure, fluid enters net arteriole: +15 outward blood pressure > osmotic pressure, fluid leaves
regulation of circulation (vascular system) ______ & ______ mechanisms Each tissue, however, regulates _____ blood flow by ___________ mechanisms that constrict or dilate _________ supplying blood. The collective autoregulatory actions of all the capillary beds influence the pressure and composition of blood. For example, if many capillary beds open all at once, blood pressure _________. The nervous and endocrine systems respond to any changes by influencing WHAT 3 THINGS?
neural & hormonal mechanisms ^control circulatory sys @ local & systemic levels --its own blood flow ----by autoregulatory mechanisms that constrict or dilate----- arterioles supplying blood. DROPS The nervous and endocrine systems respond to any changes by influencing *breathing, heart rate, and blood distribution*
t/f: seal shunts blood when it dives.
no, FALSE: SEALS has 3 chambered heart, it cannot shunt blood, and instead :( sends all blood thru pulmonary circulation (lungs) --still, the small change of vasoconstriction greatly affects resistance (^4 power) so the blood flow is largely decreased
why does contraction of skeletal muscles push blood toward the heart?
one-way valves in veins prevent backflow if veins are stretched, valves stop working well; varicose veins result No elasticity, low smooth muslce, can venoconstrict/dilate but not as much as on arterial side So, veins can contain large percentage of the blood The venous sdie oright now has some percetnage of blood; if exercising, push more onf venous blood into heart and onto arteial side, inc the arterial volume on that side which is good thign when exercising Venous side of circulation: imp bec low pressur eon venous side of circulatino , blood needs to go tfrom lower body to heart, so the one way vales are critical in preventing backflow Vericose vines: vessel are old, valves don't work as well, tendency to pool blood in lower extremeties Imp to get blood back to heart
which nervous sys is chronic and why?
parasympathetic bec the vagus nerve's chronic firing (pacemaker cells)
lipid soluble solutes can diffuse thru _____ while other soultes must diffuse thru _____ or _________
phospholipid bilayer but others: thru channels, or be moved by transport systems
describe the amazingness of crocs:
pic shows what occurs on land when easy breathin' Crocodiles have a complete ventricular septum, producing two equally sized chambers. The blood from the right and left atria is not mixed; despite this, there is an opening at the base of the right and left systemic arches, and blood can be shunted between the two. This is important during diving, when blood flow to the lungs is decreased. Crocodilians have a unique circulatory mechanism where the heart shunts blood from the lungs toward the stomach and other organs during long periods of submergence; for instance, while the animal waits for prey or stays underwater waiting for prey to rot. One adaptation includes two main arteries that leave the same part of the heart: one takes blood to the lungs and the other provides an alternate route to the stomach and other parts of the body. Two other adaptations include a hole in the heart between the two ventricles, called the foramen of Panizza, which allows blood to move from one side of the heart to the other, and specialized connective tissue that slows the blood flow to the lungs. Together, these adaptations have made crocodiles and alligators one of the most successfully-evolved animal groups on earth.
small changes in ______ largely affect ______
radius or diameter of blood vessel; blood resistance (high resistance = poor blood flow = small radius)
birds heart
separate circulations allow differential pressures in pulmonary and systemic (higher) circulations birds: -have air sacs but not as gas exchange places -respiratory sys includes all regions of ventilation and includes mouth taking air in thru esophagus into lungs, but THE ONLY GAS EXCHANGE IS IN THE ALVEOLI *The air sacs permit a unidirectional flow of air through the lungs. Unidirectional flow means that air moving through bird lungs is largely 'fresh' air & has a higher oxygen content. In contrast, air flow is 'bidirectional' in mammals, moving back and forth into and out of the lungs.* As a result, air coming into a mammal's lungs is mixed with 'old' air (air that has been in the lungs for a while) & this 'mixed air' has less oxygen. So, in bird lungs, more oxygen is available to diffuse into the blood so air sacs are part of respiratory sys but only where gas exchange happens ins IN AIR CAPPILARIES where goes to blood in body air sacs are like bellas IN birds: imp for air movement which is their purpose in birds, lets them have constant 1 way flow!!!
when croc underwater
shunt blood thru foramen of panizzae when water breathing in any of these animals or us if hold breath, get vasoconstriction in pulmonary area and get back pressure to right ventricle that has to pump harder and opens the valve (from right ventricle to aorta) and this allows most of the blood to bypass the pulmonary circulation (bec high pressure in right ventricle ) and only a little blood goes thru pulmonary (bec we have good vasoconstriction there)
what advantages do non-crocodilians (reptiles like turtles, aquatic snakes, some lizards) have bec of INCOMPLETE SEPARATION?
shunt blood to systemic, like amphibians do! ___*The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body.*
in large veins near heart, ___ also contract with exercise, increasing ____ & _____
smooth msucles venous return 2 heart and cardiac output
how can you measure blood? a normal young adult has systolic pressure of ___ and diastolic pressure of ______
stethoscope and a sphygmomanometer 120mm of Hg 80 mm of Hg 120/80
in fetus: blood from body and placenta vs blood from just body?
superior vena cava: just from body inferior vena cava: from body and placenta
in cardiac cycle, ventricle contraction is called ________ and ventricle relaxation is called _________.
systole diastole SIS'S are close, DIAS (days) gotta relax as shown in pic: in systole, the pulmonary and aortic valves open as ventricles contract in diastole, ventricle relaxes and the tri and bicuspid valves open
middle arches
the THREE CENTRAL ARCHES ARE WHAT BLOOD GOES THROUGH WHEN FISH IS IN WATER!!!!!!!! THESE ARE THE 3 FUNCTIONAL GILLS!!!!!!
in open circulatory systems, .... what do the most simple systems do?
the blood or circulating fluid is NOT SEPARATE from TISSUE FLUID --*>the most simple systems squeeze extracellular fluid (hemolymph) thru and around intracellular spaces* ---usually a* pump or heart to help PROPEL fluid, and vessels direct it, but the fluid leave the vessels and moves thru tissues, finally returning 2 heart later*. -arthropods, some mollusks (NOT cephalopods), and other invertebrates (Have heart; blood enters thru holes in heart, peristaltic contractions move the blood; most don't have vessels, they just dump blood to front
anterior gill arches
the front (top in flow diagram) gills thru which, when fish is in air, the blood that has been oxy/passed thru lungs already passes through these nonfunctional gills to get to aorta.
Arteriole smooth muscle also responds to ____ & ____ signals The _______ division of the _____ nervous system innervates most arteries and arterioles. (Review adrenergic receptor differences.) Most sympathetic neurons release ________, which causes most vascular smooth muscles to ______, thus _______ blood flow. (chronic firing) In skeletal muscle, however, some sympathetic neurons may also release __________, which causes smooth muscle of arterioles to ____ and __, thus ____ blood flow. (non-chronic)
ympathetic nerves control the skin arterioles for this purpose, with greater release of norepinephrine causing vasoconstriction. Since under neutral conditions there is some steady sympathetic activity to the skin, reduction of the sympathetic effects allows vasodilation endocrine, nerve sympathetic, autonomic norepinephrine; contract; reducing flow acetylcholine *note this is usually parasympathetic but here is sympathetic relax; dilate; increasing ___adrenergic receptors: G protein-coupled receptors that are targets of the catecholamines, especially norepinephrine (noradrenaline) and epinephrine (adrenaline).
if cut vagus nerve what happens?
you get inc hr bec the negative feedback was cut vagus normally acts to slow hr
general overview of the types of circulatory systems of animals:
•Fish have a single systemic circuit for blood, where the heart pumps the blood to the gills to be re-oxygenated (gill circulation), after which the blood flows to the rest of the body and back to the heart. •Other animals, such as amphibians, reptiles, birds, and mammals, have a pulmonary circuit, where blood is pumped from the heart to the lungs and back, and a second, systemic circuit where blood is pumped to the body and back. •Amphibians are unique in that they have a third circuit that brings deoxygenated blood to the skin in order for gas exchange to occur; this is called pulmocutaneous circulation. •The number of heart chambers, atria and ventricles, mitigates the amount of mixing of oxygenated and deoxygenated blood in the heart as more chambers usually mean more separation between the systemic and pulmonary circuits. •Warm-blooded animals require the more-efficient system of four chambers that has the oxygenated blood completely separated from the deoxygenated blood.
