II: Ch. 21

Smaller muscular arteries

Adapted for vasodilation and vasoconstriction.

Medium veins.

Go-between small veins and large veins. Fuse into large veins

Left common carotid

Up left side of body to head

Coronary sinus (heart)

Deoxy from coronary veins go to sinus

Internal elastic membrane. Fenestrated layer of elastic fibers.

Elastic membranes that then leads to tunica media

4.Regulate blood pressure

Plays role in this Heart is one of the major features that regulates BP but circ system plays a role as well

Types of veins

Superficial (closer to surface), deep (further from surface), sinuses (big)

Arteries

Take blood away from the heart 3 gen categories Elastic Muscular Arterioles

Venous sinuses

are similar in structure but even larger. E.g., spleen Largest pores Sim to sinusoids Found in spleen - filters cells in blood; Kidneys - fluid Only place blood can leave circ system without damage; whole bunch reticular fibers present

Inferior vena cava

(abdomen, pelvis, lower limbs) Deoxy blood here back to heart

Pressure

(force per unit area) How much force is being applied to the blood vasculature

Superior vena cava

(head, neck, thorax, upper limbs) Deoxy blood here back to heart

Inferior mesenteric

(takes blood to descending colon and rectum)

Superior mesenteric

(takes blood to pancreas, small intestine, colon)

Celiac trunk -

(takes blood to stomach, liver, duodenum [part intestines]); branching into left gastric, common hepatic, and splenic arteries

Splenic

(takes blood to stomach, spleen)

Physiology of systemic circulation determined by

-anatomy of circulatory system -dynamics of blood flow -various regulatory mechanisms that control heart and blood vessels

Fluid exchange across capillaries

1. At the arterial end of the capillary, the net hydrostatic pressure is greater than the net osmotic pressure. When the net osmotic pressure is subtracted from the net hydrostatic pressure, the result is a positive net filtration pressure that causes fluid to move out of the capillary 2. Approximately nine-tenths of the fluid that leaves the capillary at its arterial end reenters the capillary at its venous end. About one-tenth of the fluid passes 3. At the venous end of the capillary, the net hydrostatic pressure is less than the net osmotic pressure. When the net osmotic pressure is subtracted from the net hydrostatic pressure, the result is a negative net filtration pressure that causes fluid to move into the capillary

Baroreceptor reflex control

1. Baroreceptors in the carotid sinus and aortic arch monitor blood pressure. 2. The glossopharyngeal and vagus nerves conduct action potentials to the cardioregulatory and vasomotor centers in the medulla oblongata. 3. Increased parasympathetic stimulation of the heart decreases the heart rate. 4. Increased sympathetic stimulation of the heart increases the heart rate and stroke volume 5. Increased sympathetic stimulation of blood vessels increases vasoconstriction Homeostatic setpoint appropriate to issue Detect increased stretch decreasing sym and increase para of heart - vagus - hyperpolarized; increase HR, SV and increase BP - listen to calming music does this BP falls - detect decreased stretch - decrease parasympathetic increasing HR and SV and increase PR increases MAP bring BP back up Very quickly - within sec

Chemoreceptor reflex control

1. Chemoreceptors in the carotid and aortic bodies monitor blood O2, CO2, and pH. 2. Chemoreceptors in the medulla oblongata monitor blood CO2 and pH. 3. Decreased blood O2, increased CO2, and decreased pH decrease parasympathetic stimulation of the heart, which increases the heart rate. 4. Decreased blood O2, increased CO2, and decreased pH increase sympathetic stimulation of the heart, which increases the heart rate and stroke volume. 5. Decreased blood O2, increased CO2, and decreased pH increase sympathetic stimulation of blood vessels, which increases vasoconstriction.

Local control of blood flow in tissues steps

1. Vasodilation of precapillary sphincters Precapillary sphincters relax as the tissue concentration of nutrients, such as O2, glucose, amino acids, and fatty acids, decreases. The sphincters also relax as the concentration of vasodilator substances, such as CO2, lactic acid, adenosine, adenosine monophosphate, adenosine diphosphate, nitric oxide, and K+, increase, and as the PH decreases 2. Constriction of precapillary sphincters Precapillary sphincters contract as the tissue concentration of nutrients, such as O2 , glucose, amino acids, and fatty acids, increases. The sphincters also contract as the tissue concentration of metabolic by-products, such as CO2 , lactic acid, adenosine, adenosine monophosphate, adenosine diphosphate. Vasoconstriction and dilation can increase blood flow 7-8 times as a result of vasodilation and blood into caps; need less blood flow to tissues, vasoconstrict more - still want some blood going through but vasoconstriction and dilation want more blood flow flow into tissues by vasodilation precapillary sphincters to get more blood into tissues, can sig increase amount of blood going to tissues long term local control

BP steps

1. When the cuff pressure is high enough to keep the brachial artery closed, no blood flows through it, and no sound is heard 2. When cuff pressure decreases and is no longer able to keep the brachial artery closed, blood is pushed through the partially opened brachial artery, producing turbulent blood flow and a sound. Systolic pressure is the pressure at which a sound is first heard. 3. As cuff pressure continues to decrease, the brachial artery opens even more during systole. At first, the artery is closed during diastole, but as cuff pressure continues to decrease, the brachial artery partially opens during diastole. Turbulent blood flow during systole produces Korotkoff sounds, although the pitch of the sounds changes as the artery becomes more open 4. Eventually, cuff pressure decreases below the pressure in the brachial artery, and it remains open during systole and diastole. Nonturbulent flow is reestablished, and no sounds are heard. Diastolic pressure is the pressure at which the sound disappears

Functions of circulatory system

1.Carry blood 2.Exchange nutrients, waste products, and gases 3.Transport of hormones, components of the immune system, molecules required for coagulation, enzymes, nutrients, gases, waste products, etc. 4.Regulate blood pressure 5.Directs blood flow

Arteries and veins, not capillaries, have

3 distinct layers (layer = tunic or tunica)

Poiseuille's Law

A law that describes fluid dynamics - very simply says flow decreases when resistance increases and vice versa Flow decreases when resistance increases and vice versa. Since resistance is proportional to blood vessel diameter, constriction of a blood vessel increases resistance and thus decreases flow Smaller diameter - more resistance and vice versa Resistance and flow equation together get this law Flow =(P1 -P2)/R = p(P1 -P2)D4/128vl

causes simultaneous ↑ reabsorption of water in the kidney and vasoconstriction and effect on BP

ADH Increases BP ADH - only increases water kidney and simultaneously causes vasoconstriction; ONLY WATER

Renin-angiotensin-aldosterone mechanism/system

Aldosterone - mineralocorticoid produced by adrenal cortex - endocrine system - not in terms of CV system Series of hormones renin and angiotensin responsible for regulating this system RAAS 1. Kidneys detect decreased blood pressure, resulting in increased renin secretion 2. Renin converts angiotensinogen, a protein secreted from the liver, to angiotensin I. 3. Angiotensin-converting enzyme in the lungs converts angiotensin I to angiotensin II. 4. Angiotensin II is a potent vasoconstrictor, resulting in increased blood pressure. 5. Angiotensin II stimulates the adrenal cortex to secrete aldosterone. 6. Aldosterone acts on the kidneys to increase Na+ reabsorption. As a result, urine volume decreases and blood volume increases, causing blood pressure to rise. Mechanism to increase blood pressure; maintain homeostatic setpoint for BP Done couple ways: vasoconstriction and the amount of fluid that is left in blood Pull togeth CV system and urinary system; why CV failure and kidney failure often hand in hand Prob is decrease BP - BP too low and want to increase it Kidneys responsible for filtering fluid in your blood - filter all of your fluid so are very sensitive to changes in BP - baroreceptors that detect decreased BP Kidneys detect decreased BP and response is secrete hormone called renin - which goes into circ system there it acts on a preenzyme called angiotensinogen - preenzyme that does not do anything but one proteins liver produces renin converts angiotensinogen into angiotensin I - lungs produces ACE - angiotensin converting enzyme; ACE converts angiotensin I into angiotensin II which acts on the adrenal cortex in gland to secrete aldosterone - mineralocorticoid - which moves through circ system to the kidney where it then acts on kidney causing the kidney it to reabsorb less water; increase water reabsoprtion means you are peeing out less decrease urine volume increasing blood volume which puts more pressure on walls of vessels increase BP Not very fast - lot of steps Can take hours - long term regulation At same time angiotensin II causes vasoconstriction which will increase BP This system/mechanism increases the amount of water being reabsorbed in the kidneys and going back into blood increasing blood volume which increases BP because more fluid in an enclosed system Angiotensin II increases vasoconstriction increasing PR which increases MAP - this is a long-term regulation of BP - this mechanism/system Increased BP decreases renin and aldosterone production; decrease vasoconstriction and increase vasodilation

Smooth muscle in arterioles, metarterioles, precapillary sphincters regulates blood flow

All branches want to be able to carefully control amount blood flowing into tissue so have precapillary bed sphincters - lot imp Sphincters - control blood flow to tissues

Smooth muscle allows vessels to regulate blood supply by constricting or dilating

Allow vasodilate and vasocontrict which helps them control amount blood going into tisuses More blood into tissues - vasodilate because increases volume Less blood into tissue - vasoconstrict so less blood going into tissues

TOP -

Also pulling force tissues been metabolizing so they are producing lot waste products and having that go into interstitial fluid causing it to build up; so higher concentration of solute that is going to pull out of arteriole end of cap into tissues

Laplace's Law

Also think of this with blood vessels Keep BP and increase diameter of vessel the force acting on vessel increases Big blood vessels like in aorta under highest pressure because closer to heart and 2 because of this law under most pressure Why do not take blood from artery under higher pressure and highest pressure is aorta so have to worry about aortic aneurysms - arteries aneurysm are concern because under high pressure and bigger the diameter the higher the pressure so if have leaking part of aorta is under high pressure can bulge out and have an aneurysm which can potentially tear and bleed to death - application to CV pump Force acting on blood vessel wall is proportional to diameter of the vessel times blood pressure F= D X P; thus as diameter of a vessel increases, force on the wall increases. Weakened part of a vessel wall bulges out and is an aneurysm.

volume (Blood flow determined by physics (cannot be modified) and the following that can by physiologically altered:)

Amount of blood and/or amount of fluid in blood Some influence over blood volume Flow means volume moving per unit time Do this by more volume Have diff ways can control blood volume ADH - can be utilized to increase BP because increases amount water reabsorped in kidneys and goes back into blood increasing blood volume and BP Aldosterone too Very strong link between CV health and kidneys

Atrial natriuretic mechanism/factor/ANH or ANF

Another hormone Opp = Not doing anything and drinking lots water - pee a lot more - funcitoning kidney that is what is happening Released from cardiac muscle cells so when detects increased atrial blood pressure, more blood being returned back to RA causes more stretch and pressure in RA, which then causes release of ANH which stimulates an increase in urinary production, putting more water into urine and offloading urine in body causing a decrease in blood volume and blood pressure Opp ADH - outside in heat and losing lot a fluid via sweating, pee less and when do pee a lot more concentrated and lot less water in it because ADH secreted and reabsorbing more water in kidneys and more water going back into circ system Released from cardiac muscle - detects increased atrial BP - more blood returned to RA causing more stretch and pressure so causes release of ANH offloading water off of body decreasing blood volume decreasing BP Diuretics increase urine production means offload more water in urine which decrease water in blood plasma which decreases blood volume and decrease BP

Ventilation (pump)

Another mechanism As breathe in and out are shifting fluid in abdomen; IVC running along on back of abdominopelvic and movement fluid pushes onto the VC and veins helping blood return back to heart Breathing helps

Systemic circulation

Aorta

Describe the difference between an artery, capillary, and a vein in as few words as possible.

Arteries - away from heart; elastic; more muscular than cap and veins; higher pressure than cap and generally veins; aorta has highest BP (artery with highest because closer to heart) Capillary - in between arteries and veins; exchange; very small; lots ofbranching (really branch) Veins - to the heart; valves - imp to limit backflow; thinner than arteries but thicker than capillaries

Photomicrograph of artery and vein

Arteries lot more smooth muscle than veins Arteries have thicker tunica media, more smooth muscle, than veins - veins collapse more and arteries do not

Blood flows from arterioles through metarterioles, then through capillary network

Arterioles branch into metarterioles arterioles branch into metarterioles which are what lead directly into cap bed - which is a big number of branches that go through tissues

Arteriovenous anastomoses:

Arterioles to small veins with no capillaries Blood vessels that connect arterioles directly to small veins with no capillary beds Arterioarteriole anastomoses- Blood vessels connect two arterioles together; in heart; one blocked up to ensure redundancy Circle of Willis - have a lot of redundancy in the blood vasculature brain because if one blocked can go around it Connect between arteries and arteries or arteries and veins = anastomoses Sole of foot, palm of hand, terminal phalanges (fingertips), nail beds Temperature regulation - direct blood flow away from the surface of the body to keep it more internalized - do via Arteriovenous anastomoses in hands - frostbite in toes, fingertips, nose, ears because cartilage - not lot blood flow

Aging of the arteries

Arteriosclerosis: Atherosclerosis:

Aortic arch

Ascending aorta - first branch right and left coronary arteries taking oxy blood to heart Arch - because it is an arch - brachiocephalic artery heading off to right which then branches into right subclavian (heading to arm) and right common carotid (head); left common carotid artery; left subclavian; 3 branches off aortic arch, not 4 because we think humans symmetrical; first branch is brachiocephalic

4 fluid pressures

BCOP or BOP = blood colloid osmotic pressure/Blood osmotic pressure BHP = blood hydrostatic pressure (or capillary filtration pressure) TCOP or TOP = interstitial (tissue) colloid osmotic pressure (ICOP)/tissue osmotic pressure THP = tissue hydrostatic pressure (interstitial fluid pressure or IFP) (include lymphatic vessel in this overall process) Net filtration pressure (NFP) = net hydrostatic pressure (BHP - THP) - net osmotic pressure (BOP - TOP)

Decreases in plasma concentration of protein reduces BCOP; more fluid moves into interstitial fluid

BOP = blood osmotic pressure; have a series albumins, proteins in blood produced by liver, that are partially responsible for controlling blood osmotic pressure - something extensively regulating Liver disease resulting in fewer plasma proteins Loss of plasma proteins through the kidneys Protein starvation Have to control blood osmotic pressure - regulated in homeostatic norms Blockage or removal of lymphatic vessels (blockage: elephantiasis; removal: cancer)

Hydrostatic pressure Determined by:

BP - physical contractions of the heart pushing blood Fluid accumulation - pushing back in interstitial space; interstitial fluid accumulating

Affected by: (Blood pressure, capillary permeability, and osmosis affect movement of fluid from capillaries)

BP affects it how permeable capillaries are osmosis

Long-term control of BP

BP increases BP decreases Anything ever see physiological system that is complex and has in lots steps - reason is that it is there to control the process; lot steps in aerobic respiration; highly controlled process; can burn sugar but do not want that in cells which is part reason why aerobic respiration very controlled - lots steps and lot points of control

BP falls

Baroreceptors detect decreased stretch and going to decrease para of heart and increase sym of heart and vessels increasing HR, SV, PR, increases MAP increasing BP

BP increases homeostasis disturbed

Baroreceptors detect increased stretch and going to decrease sym stimulation and decrease sym stimulation of vessels and increase para stimulation of heart - vagus nerve which hyperpolarizes SA node decreases HR, SV, increases dilation in vessels, decreasing BP Relaxing music - increasing para stimulation of heart

Blockage or removal of lymphatic vessels (blockage: elephantiasis; removal: cancer)

Blockage - elephantiasis - due to a parasite Removal something happened or had remove them for cancer treatment - such as breast cancer in either male or female see compression sleeve and have compression on tissues so no accumulation of fluid in arm

During exercise, heart beats with greater force increasing pressure in the aorta. Capillaries to skeletal muscle increase in diameter decreasing resistance and increasing flow. Increased flow in aorta can go from 5L/min to 5 times that amount

Blood flowing - exercise - heart beats faster and increase HR - beats with greater force so increasing SV - pushing more blood out with each ventricular contraction increasing pressure you are pushing more blood into circ system; in skeletal muscles because engaging in phys activity those are contracting with more frequency so using more ATP sliding actin and myosin so need more oxygen - vasodilate capillaries to have sig diameter increasing blood flow into those tissues Increased flow in aorta in response to changes in HR and SV Increase flow into tissues by increasing diameter

MAP =

CO(PR), MAP = HR(SV)(PR)

Capillary exchange and regulation of interstitial fluid volume

Capillaries are where exchange takes place - where offload glucose, oxygen, AA, transport molecules: hormones, lipids, materials; also where you pick up waste products - picking up CO2 in tissues and picking up hormones, various products, waste products, ammonium, urea, whatever cellular product is = exchange is critical feature of capillaries Sev diff factors impact exchange because if start issues with probs get healthcare issues - edema Capillary exchange: Most important means of exchange: diffusion. Blood pressure, capillary permeability, and osmosis affect movement of fluid from capillaries Fluid moves out of capillaries at arterial end and most but not all returns to capillaries at venous end. That which remains in tissues is picked up by the lymphatic system then returned to venous circulation.

Capillary beds in intestines that empty into hepatic portal vein that nutrient-rich oxygen poor to cap beds in liver to go through detoxification

Capillaries draining GI tract → hepatic portal vein → liver sinusoids (large caps in liver) →hepatic veins Cap beds in digestive tract - eaten something and getting nutrients into capillary beds - diffusing across the epithelial tissue of intestines into cap beds, nutrient rich O2 poor blood then goes to cap beds in liver where it is detoxified - this nutrient rich oxygen poor goes to hepatic vein to IVC where then in heart; right side heart pumps the nutrient rich O2 poor blood to lungs where picks up oxygen and returns back to heart and now heart pumping oxygen and nutrient rich out to the body

Laminar and turbulent flow

Causes sounds - changes in flow 2 gen categories to fluid dymanics/flow BP - taking adv of the flow

Chemoreceptor reflexes:

Chemical receptors - detect diff concentrations H+ levels as well sensory receptors sensitive to oxygen, carbon dioxide, and pH levels of blood Chemoreceptors in carotid artery and aortic artery and medulla oblongata - detects O2 - very imp to get to tissues; have a lot receptors for CO2 and H+ Is responsible for regulating O2 - although primarily CO2 - responsible for regulating pH - CO2 and H+ relationship Detect decreased blood O2 and increased CO2 and decreased pH and increased H+ Blood not over react to increased O2 levels but a decrease CO2 decreasing H+ making more alkaline (more risk for alkalosis)

If capillaries become more permeable, proteins can leak into the interstitial fluid increasing ICOP. More fluid moves from the capillaries into the interstitial fluid: edema. Things can cause edema

Chemicals of inflammation increase permeability Decreases in plasma concentration of protein reduces BCOP; more fluid moves into interstitial fluid Blockage of veins increases capillary BP; reduced venous return due to gravity

2.Exchange nutrients, waste products, and gases

Circ system links respiratory system and digestive system to the rest of your body Respiratory system - where getting O2 into blood and out CO2 Digestive - where getting water, carbs, lipids, AA, almost all of your ions; need iron to make hemoglobin getting that from food into digestive system where crosses epithelial tissue and goes into circ system This means circ system is transporting all of these diff things to tissues where once gets to tissues has to offload product - glucose, water, O2, AA, fatty acids, tricglycerades Then at tissues also picks up waste products - via aerobic respiration body producing CO2 which diffuses out of tissues into blood to be transported and waste products - lactic acid in muscles, ammonioum (when metabolize AA produce ammonium (byproduct of metabolism of AA - transported then made into urea in liver then transported into kidneys where excreted) Major func of circ system

Osmotic pressure Determined by

Concentration of solutes (plasma) or in interstitial fluid Large proteins - blood and albumins necessary for maintaining osmotic pressure - large proteins in your blood responsible for controlling osmotic pressure of blood this means they do not leave blood - large and not able to easily move in and out of capillary beds so used to control solute concentration in blood and interstital fluid (between tissues)

BP - taking adv of the flow

Constricting brachial artery and then able to listen for sounds and determine BP from that - how traditional BP taken

Diff types of capillaries

Continuous Fenestrated Sinusoidal Sinusoids Venous sinuses

Pressure (Blood flow determined by physics (cannot be modified) and the following that can by physiologically altered:)

Control the Rate of heart contractions Via mechanisms in ch. 20 Control the Force of heart contractions Via mechanisms in ch. 20 Force per unit area

Resistance

Deals a lot with vasoconstriction and dilation one other thing determines blood circulation dynamics is resistance Developed way developed and cannot redesign arteries unless major surgery - the architecture is fixed so think about pressure, flow of blood, and resistance

BP too low

Decrease para and increase sym stimulation of heart; increase HR, SV, and PR of blood in circ system, and increases BP Adrenergic receptor type specific Increasing BP vasodilation of coronary arteries - while rest have constriction of tunica media in vessels

Detect decreased blood O2 and increased CO2 and decreased pH and increased H+

Decrease para stimulation and increase sym to increase HR, SV, and PR increasing BP Not enough O2 Increased CO2 concentrations in blood

BP increases

Decrease renin from kidney, decrease ADH from PP, increase ANH/ANF from heart Happens: going to vasodilate vessels and reabsorb less water in kidneys and leave more water in urine decreasing blood volume and increase vasodilation and decrease vasoconstriction bringing BP back down

Increased resistance to blood flow

Degenerative changes have increase resistance to blood flow Peripheral resistance goes up and hypertension goes up Tend to see higher BP as individuals age

Viscosity relates to this/factors into this

Dehydrated or taking EPO or has prob in kidneys and uncontrolled EPO causing way too many RBC production have viscosity issues During exercise, heart beats with greater force increasing pressure in the aorta. Capillaries to skeletal muscle increase in diameter decreasing resistance and increasing flow. Increased flow in aorta can go from 5L/min to 5 times that amount

Abdominal aorta and its branches

Descending aorta Celiac trunk - Splenic Superior mesenteric Inferior mesenteric Aorta below the diaphragm; branches out to a lot of diff structures in abdomen - need lot blood flow Splits into right and left common carotid arteries

Aging

Did not die young - value of aging Related to peripheral circulation Degenerative changes (arteriosclerosis, atherosclerosis, etc.) Increased resistance to blood flow

Most important means of exchange: diffusion.

Diffusion - dictates how much O2 tissues get and how much water tissues get; diffusion = critical; from area of high to low concentration - dictates directionality of things Lipid soluble easily diffuse cross capillary walls or really small stuff; diffusing through plasma membrane. E.g., O2, CO2, steroid hormones, fatty acids. Water soluble diffuse through intercellular spaces or through fenestrations of capillaries beds. E.g., glucose, amino acids.

Hepatic portal system

Digestive system Portal vessels - type blood vessels - connect two cap beds and no pump between them through rest of body Portal system: Hepatic portal- Blood entering the hepatic portal vein is rich with nutrients collected from the intestines, but may also contain toxic substances. Both nutrients and toxic substances will be regulated by the liver Capillary beds in intestines that empty into hepatic portal vein that nutrient-rich oxygen poor to cap beds in liver to go through detoxification

5.Directs blood flow

Directs all blood to the appropriate parts of body Vasoconstriction, dilation, and sphincters responsible for that

Viscosity of blood (Blood flow determined by physics (cannot be modified) and the following that can by physiologically altered:)

Do not want huge changes in viscosity and hematocrit but does happen; and hydration state Do not want huge shifts in hematocrit - does happen because of internal bleeding Hydration state - chronic dehydration - blood vasculature decreases and increased BP and other issues with this

Lipid soluble easily diffuse cross capillary walls or really small stuff; diffusing through plasma membrane. E.g., O2, CO2, steroid hormones, fatty acids.

Easily diffuse across walls or really small stuff Exchange of those things in capillary beds

Elastic arteries

Elastic fibers present in arteries - lot of elastin Means return to an original resting shape; can stretch it out then it will snap back - elastic They stretch out then snap back - throbbing - stretching out then snapping back - feel elastic artery in neck These diverge/split into muscular arteries Biggest elastic artery is aorta - branch into muscular arteries which branch into arterioles which then branch into a large number capillary beds Or conducting arteries More elastic Like interstates - they are there to get max number of RBC out to tissues as fast as possible Largest diameter so highest pressure Typically are closest to heart Systole - ventricles contracting pushing blood out and have high pressure and as feel pulse can feel it push out Lot more elastic tissue than muscle Largest diameters, pressure high and fluctuates between systolic and diastolic. More elastic tissue than muscle. Relatively thick tunica intima, thin tunica adventitia and tunica media Tunica media mostly elastic CT; recoil when stretch, which prevents blood pressure from falling rapidly

Tunica intima

Endothelium - epithelial tissue that opens into internal part of body; opens internally Innermost layer Intima - Most intimate; inside Basement membrane Lamina propria (C.T. layer) - this means CT layer Internal elastic membrane. Fenestrated layer of elastic fibers.

Adrenal medullary mechanism

Epi and nor hormones secreted from adrenal medulla in response to sym stimulation Increase epi and nor increase HR and SV (force of contractions) Also do in gen cause vasoconstriction with an alpha receptor in the peripheral circ system and vasodilation acts on a beta receptor - when it depends on type of receptor In gen - rule of thumb, increase epi increase PR increases BP in the whole body; some exceptions particularly in the coronary arteries Activated when stimuli result in a substantial increase in sympathetic stimulation of heart and blood vessels (large decrease in blood pressure, sudden and substantial increase in physical activity, stress) Adrenal releases epinephrine and norepinephrine Hormones mimic sympathetic stimulation of heart and blood vessels. Epinephrine acts on alpha receptors causing vasoconstriction and on beta receptors causing vasodilation

Increased blood volume

Explanations why diet very high in salt can increased BP Increased dietary salt changes osmotic pressure in blood and keep more fluid in blood and increase blood volume and more blood to heart which means more blood and harder contractions Increase in blood volume - more blood and increases venous return

Anatomy of circulatory system

Fixed - not change unless there is an accident

Blood flow determined by physics (cannot be modified) and the following that can by physiologically altered:

Flow - Movement of blood per unit time - not talked about pressure; things increase BP may not necessarily increase blood flow - may be some opposition Flow determined by phsycis and cannot change laws of physics and cannot change architecture of blood vessels Physiologically tho are some things can affect; can influence below Pressure volume Viscosity of blood Regulation =

Flow = (P1 - P2/R)

Flow - blood moves from area of high to low pressure - going to have a pressure difference Pressure at location 1 and location 2 EX: Ascending artoa - 1 and Aortic arch - 2 Flow is directly proportional of pressure Greater the pressure more flow; lower pressure = less flow Indirectly proportional to resistance Something to go faster - more force into pushing it - physics of pressure difference - put more pressure to get blood faster - more flow more pressure; something pushes back, resistance decreases things go faster and easier to move; if resistance increases it becomes harder - same principles with blood just have this equation Increases when increase pressure - increase HR and SV increases pressure of blood leaving heart; decreasing HR and SV decreases pressure; blood flow is inversely proporitional to resistance - increase resistance (diameter smaller) decrease resistance - decrease diamgeter Talking about flow not pressure Volume that passes specific point per unit time

Edema and capillary exchange

Fluid directionality not 100% - not working are probs where can accumulate too much fluid in tissues; CV or kidney disease - ask see ankles because looking for accumulation in fluid in lower extremities Heart failure - can accumulate a lot of fluid in abdomen and can leave fingerprints Edema - accumulation of fluid in tissues If capillaries become more permeable, proteins can leak into the interstitial fluid increasing ICOP. More fluid moves from the capillaries into the interstitial fluid: edema. Things can cause edema

Blood pressure, capillary permeability, and osmosis affect movement of fluid from capillaries

Fluid inside blood and move across the endothelial tissue into interstitial fluid surrounding cells that is where goes after capillary bed then material goes from interstitial fluid into cells; material leaving the tissues from cell into interstitial fluid then into capillary bed Affected by:

Fluid moves out of capillaries at arterial end and most but not all returns to capillaries at venous end. That which remains in tissues is picked up by the lymphatic system then returned to venous circulation.

Fluid moves out of capillaries on arteriole end; venual capillaries - venous side - most, not all, return on venous side Little bit left over; fluid can accumulate in tissues Another set vessels of vasculature - lymphatic system responsible for returning excess fluid back to venous circulation; lymphatic removed from arm wear compression sleeve - keeps fluid from accumulating in tissues and helps return more to capillary beds

Blood pressure

Force per unit area Blood moves from area high to low pressure and heart moving that - that is the pump Measure of force of fluid, blood, on walls of blood vasculature Way measure BP is to listen to Korotkoff sounds - produced by turbulent flow in arteries as pressure is applied Measure of force exerted by blood against the wall Blood moves through vessels because of blood pressure Measured by listening for Korotkoff sounds produced by turbulent flow in arteries as pressure released from blood pressure cuff BP taken

Pressure:

Force per unit area. In this case force of the blood on the walls of the blood vessels. Pressure is proportionate to flow. Increase pressure, increase flow. Vice versa.

Resistance:

Forces that impede the flow of blood.

Structure of capillary walls

Form fits func - way something is structured fits its job; happening in tissues and going on

Aortic arch:

Forms an arch Literally arches over - look like arch Noticeable not symmetrical arching posteriorly and to the left and has three branches coming off of it 3 branches Brachiocephalic artery Left common carotid Left subclavian artery Arches over then descends

Venules

From capillaries to here Little veins Ule - little Fuse into small drain capillary network. Endothelial cells and basement membrane with a few smooth muscle cells. As diameter of venules increases, amount of smooth muscle increases. Take blood away from tissues Minimal and small basement membrane with arteries venules taking blood away from tissue and very small minimal basement membrane in comparison to arteries Diameter in the venules increases with increase SM muscle These Fuse into small veins

Vasopressin (ADH) mechanism

From endocrine system Osmoreceptors detect increased osmotic pressure means increased solute concentration in the blood so there is not enough water in the blood or detect decreased BP in those baroreceptors Happen is send AP through hypothalamic neuron causing release of ADH from PP, ADH produced by hypo but released by PP ADH moves through circ system where causes vasoconstriction of vessels hence vasopressin Other part - ADH - there goes to kidneys and increases water reabsorption as well; so decrease urine volume going to reabsorb more of the fluid back into blood and more water in blood means more blood volume which increases BP

Small veins

From venules to medium Smooth muscle cells form a continuous layer. Addition of tunica adventitia made of collagenous connective tissue Little bit more CT and smooth muscle Fuses into medium

Left subclavian artery

Going out to left arm

Brachiocephalic artery

Going out to right

Control of blood flow in tissues

Gone through pump of heart, arteries, caps, veins; now talking about this Want to do this carefully Do not want fluid going into tissue that does not need it and want to control directionality of movement - and meet metabolic needs of tissue Local control:

Rise in pH

H+ decreased so response is slow HR

3 things that dictate MAP or BP

HR SV PR If any of these go up, MAP goes up

MAP α

HR, SV, and PR. If any of these go up, so does MAP.

In a standing position, hydrostatic pressure caused by gravity increases blood pressure below the heart and decreases blood pressure above the heart.

Has to do with physics Part of venous return and muscular movement

BP too high

Have Barorecetors in aorta and carotid sinuses detect stretch - increase pressure, increase going out; decrease pressure more in; send AP to cardioregulatory center in medulla and if BP too high, will decrease sym stimulation of vessels increasing vasodilation; decrease sym of heart and increase para of heart decreasing HR and SV and PR and BP

Muscular arteries

Have a lot of smooth muscle Split into arterioles Main city streets - have a lot smooth muscle or medium arteries Splenic, femoral - main ones Smaller muscular arteries Tunica media thick layer of smooth muscle; regulate blood flow to diff regions of body Regulate blood flow to the tissues

Some blood vessels innervated by myelinated fibers and act as baroreceptors that monitor stretch and detect changes in blood pressure

Have baroreceptors - reflex; have to know what going on in blood vasculature Myelinated fibers that monitor stretch and detect changes in BP

Fenestrated

Have pores. Endothelial cells have numerous fenestrae. Fenestrae are areas where cytoplasm is absent and plasma membrane is made of a thin, porous diaphragm. Highly permeable. E.g., intestinal villi, ciliary process of eye, choroid plexus, glomeruli of kidney Fenestrae - are pores/holes Means have little holes Found capillary beds with little holes in places where need get lot stuff from membranes into tissues Inside intestines - getting into body: carbs, AA, lipids, all of your nutrients so have very porous/fenestrated capillary beds Ciliary in eye - responsible for producing lot fluid in eye Choroid plexus - in brain that is responsible to produce CSF - making fluid to protect brain so need that Glomeruli of kidney - kidneys filter your blood, the glomeruli are the filter - have fenestrated capillaries there because want to get material out blood and fluid into kidneys for filtering

1. Vasodilation of precapillary sphincters Precapillary sphincters relax as the tissue concentration of nutrients, such as O2, glucose, amino acids, and fatty acids, decreases. The sphincters also relax as the concentration of vasodilator substances, such as CO2, lactic acid, adenosine, adenosine monophosphate, adenosine diphosphate, nitric oxide, and K+, increase, and as the PH decreases

Have some local influence and reflexes that vasodilate and constrict precap sphincters as well as response to metabolic needs

Route RBC leaving heart into tissue

Heart -> Elastic arteries leaving heart → branching to muscular arteries → branching to arterioles → branching to metarterioles → thoroughfare channels → past precapillary sphincters → through arterial caps → through venous caps → fuse venules → fuse small veins → fuse med/lg veins and return back to heart

Structural features of blood vessels

Heart to Arteries to capillaries which fuse into veins which go back to the heart Arteries Capillaries: Veins:

Gravity (we're not going to talk about this)

Helps as well It is a mechanism of venous return

Pressure and resistance

Highest BP in the aorta and lowest in the vena cava - pressure decreases as you move from aorta back to the vena cava; not velocity or blood flow Feel pulse - alternation of in systolic and diastolic pressure - BP is the average between the too and drops in capillaries and veins Lowest BP in vena cava Blood from veins - lower pressure so less likely to bleed out; IV into veins because if prob less likely for them to bleed out Blood pressure averages 100 mm Hg in aorta and drops to 0 mm Hg by the time the blood gets to the right atrium. Due to decreased resistance to flow as cross-sectional area increases. Greatest drop in pressure occurs in arterioles which regulate blood flow through tissues No large fluctuations in capillaries and veins Muscular arteries and arterioles are capable of constricting or dilating in response to autonomic and hormonal stimulation. Muscular arteries regulate flow into a region of the body; arterioles regulate flow into a specific tissue.

Baroreceptor effects

Homeostatic set point for BP which needs to appropriate for situation in BP increases homeostasis disturbed BP falls Happens pretty quickly Scared - seconds able to jump and run away - heart suddenly starts beating - very fast

3.Transport of hormones, components of the immune system, molecules required for coagulation, enzymes, nutrients, gases, waste products, etc.

Hormone - released into circ system where transported Various components of your immune system - vaccines producing antibodies in the blood so blood is transporting antibodies; have WBC that are responsible for your defense against pathogens and they are transported in blood Coagulation - fibrinogen and those clotting factors present in blood All sorts enzymes

Flow

How is blood flowing through the body Hematocrit - is a very good indicator of viscosity of blood; stickiness of blood which influences flow Also influenced by flow smoothly and easily through nice round, uniform pipe but will have constrictions - happens

2 categories of pressure

Hydrostatic pressure - physical pushing Osmotic pressure - chemical pulling

Venous compliance (less blood left in veins)

If increase venous tone, increase constriction helps get more blood back to the heart

Blood pressure and the effect of gravity

In a standing position, hydrostatic pressure caused by gravity increases blood pressure below the heart and decreases blood pressure above the heart. Muscular movement improves venous return.

Flow through thoroughfare channel fairly consistent while flow through arterial capillaries is intermittent

In cap bed have one main channel, thoroughfare channel, where have fairly consistent blood flow Relatively steady blood flow through the channel

Blood vasculature has neural innervation: nerves innervating smooth muscle of blood vessels

In gen almost always sympathetic; most sig amounts of innervation

Local control:

In most tissues, see blood flow is proportional to metabolic needs of tissues Local - at that particular location Metabolism - whole organism func - can divide it into diff tissue types - epithelial, connect, and muscular, and nervous - can divide into diff types of muscle tissue; neural tissue needs lot O2 and glucose; skeletal muscle - lot O2 and glucose; metabolic needs of tissues have more blood flow to those tissues and more cap beds to tissues because they have greater oxygen needs Adipose tissue and CT - very low metabolic rate but not zero Cartilage - no cap beds in these cartilage beds because metabolic needs of chondrocytes are extremely low Are matching blood flow to metabolic needs of tissues Build more caps Constriction and dilation of sphincters increase 7-8 times because more blood flow into caps; less blood flow to tissues; vasoconstrict Want more blood into tssue - dilate sphincters getting more blood into tissues increase sig amt blood in tissues Local control of blood flow in tissues Nervous System: Hormonal Control:

Opp = Not doing anything and drinking lots water - pee a lot more - funcitoning kidney that is what is happening

In that kidneys reabsorbing less water - excreting more of it out via urination - also regulated by a hormone - Atrial natriuretic hormone/ANH

Ways increase blood flow -

Increase pressure and decrease resistance Specifically can increase diameter increasing flow

PR

Increase vasoconstriction increase PR Diff than flow; increase vasodilation have more blood in vessel that increasing flow; flow volume moving through; pressure - force of blood on walls of blood vessel As increase restriction and vasoconstrict you pushing in on fluid causing it to push back more; increases pressure

Increase with venous return

Increased blood volume Venous tone

converts angiotensinogen to angiotensin and stimulates release of aldosterone and effect on BP

Increases BP Angiotensin II - causes increased vasoconstriction

Venous tone

Increasing vasoconstriction puts more blood back to heart Compliance is how much blood the blood vessels can hold Constriction of smooth muscle in veins Increased vasodilation more blood left in venous side and less back to heart Increase vasoconstriction - getting more blood back to heart Sympathetic NS component of ANS is constantly stimulating smooth muscle in veins so get some venous return; want keep blood going back to heart; do not want lot blood accumulating in venous tissue because then have probs - going to have number probs in getting back to heart continual state of partial contraction of the veins as a result of sympathetic stimulation

Chemicals of inflammation increase permeability

Inflammatory chemicals - inflammation useful part of immune system but if not regulated properly it can cause probs - one of them is increase permeability of capillary beds so you accumulate fluid Pimples - common - red and inflamed - swollen and sore - because accumulating fluid in tissues - increasing blood flow and fluid

Basement membrane

Is a major feature of epithelial tissue

Loss of plasma proteins through the kidneys

Kidneys diseased/damaged and are letting too much protein in urine and losing too much protein causing fluid accumulation in tissues

Sinusoids

Large diameter sinusoidal capillaries. Sparse basement membrane. E.g., liver, bone marrow. Larger diameter that Sinusoidal capillaries Very little basement membrane Liver - produces large number albumins, globulins, and fibrinogen proteins - making very large molecules; also in process of getting rid of damaged RBC Bone marrow - make RBC - get them into circ system and get them into there through pores in capillary ped; exchange of immature cells going into the blood and bone marrow Larger pores

Sinusoidal

Large diameter with large fenestrae. Less basement membrane. E.g., endocrine glands (large molecules cross their walls). Oidal - Little sinuses Larger in diameter and means large fenestrae Seen in endocrine glands - making big molecules, big protein hormones, glycoprotein hormones, etc; making big molecules that have to get into the blood

Central nervous system ischemic response:

Last ditch effort to keep you from dying; keep the brainstem alive Occurs when blood flow into brainstem, medulla oblongata, decreased a such sig level that have developed veryhigh CO2 or H+ in brainstem causes short-term/temp vasoconstriction in brainstem - idea is get BP to brainstem which is critical and prob so vasoconstrict to increase BP; if goes on for more than couple mins brain death occuring; very likely die; may have serious brain damage depending on how long lasts Brain doing everything can to stay alive This going on there is a very serious prob - needs medical attention immediately Had not enough O2 - too high levels CO2 and too high levels of H+ in medulla oblongata so have very short term increase in vasoconstriction of vessels in brainstem; very short term response to try to get BP up - situation where BP fallen below 50 mmHg - very low; this just increases pressure in medulla oblongata not getting more blood back to lungs for oxygenation; more than few min have medulla oblongata brainstem tissue dying and results in death; short term increase in vasoconstriction in brainstem in critical issue Not really regulation - probs happened and trying to stay alive as long as possibe Elevation of BP in response to a lack of blood flow to the medulla oblongata. Functions in response to emergency situations and BP falls below 50 mmHg Neurons of vasomotor center strongly stimulated; increases blood flow to brain if vessels are intact but at the same time, decreases oxygenation of blood because blood does not go to lungs. Lack of oxygen causes vasomotor center to become inactive; extensive vasodilation follows with concomitant drop in BP. Death if CNS ischemic response lasts longer than a few minutes.

Substances move through capillaries by diffusion:

Lipid-soluble and small water-soluble molecules through plasma membrane Larger water-soluble molecules pass through fenestrae or gaps between endothelial cells.

THP =

Little more give here Can only put so much fluid in tissues before they start swelling - swelling causes damage and causes issues so that is to create some pushing back as put fluid into tissues and they are going to fill up and push back This process can go wrong; can accumulate so much fluid in tissues (edema) and can push into flesh where leave fingerprints and that means have prob accumulating fluid - situation abnormal and not working If working, accumulate fluid on arteriole and goes back out to venule side of cap

Blood flow

Measuring BP - you are measuring systolic (heart contracting) and diastolic (heart relaxing) - taking adv of noises produced by brachial artery in response to changes from laminar to turbulent flow Flow - want blood to flow through circ system because if stops flowing not getting enough O2 to tissues and CO2 from tissues so have to think about rate of flow How much fluid moving through vasculature Is expressed as volume that passes specific point per unit CO - how much blood pumped/unit time; Reference it as an effect of rate and force of contractions CO - how much volume being pumped; at rest - 5L/min; directly tell us how much moving through aorta (5L/min); relationship of CO with flow Rate of flow through a tube is expressed as the volume that passes a specific point per unit of time. E.g.; cardiac output at rest is 5L/min, thus blood flow through the aorta is 5L/min Flow = (P1 - P2/R) P1 and P2 are pressures in the vessel at points one and two; R is the resistance to flow Directly proportional to pressure differences, inversely proportional to resistance Resistance = 128vl/pD^4 Blood flow increases

Regulation of MAP

Mechanisms that maintain arterial blood pressure within a normal range of values BP - low kills quickly and high kills slowly; humans more biased towards higher because too low you pass out MAP - affect of heart and CO = HR x SV; PR - is vasoconstriction or vasodilation of the blood vessels - are the two components that make up MAP - CO (heart) times PR = MAP Increase HR and increase CO and increase SV (force of contractions) and increase amount blood pumped/beat increase CO PR More volume when dilate; increase pressure by vasoconstriction and now coming out with more force increasing pressure MAP - talking about CO(PR) 3 things that dictate MAP or BP Are a series mechanisms present to regulate MAP MAP between systolic and diastolic Mean arterial pressure (MAP): slightly less than the average of systolic and diastolic pressures because diastole lasts longer than systole. Approximately 70 mmHg at birth, 100 mmHg from adolescence to middle age, 110-120 mmHg in healthy older individuals.

Long-term regulation of BP

Minutes, hours, days Renin-angiotensin-aldosterone mechanism/system Vasopressin (ADH) mechanism Atrial natriuretic mechanism/factor/ANH or ANF Fluid shift mechanism Stress-relaxation response

Other vessel types

More diff types blood vessels than arteries, capillaries, and veins Separate types of blood vessels Vasa vasorum: Portal veins: Arteriovenous anastomoses:

Blood volume

Most blood volume in the veins (greater compliance) Smaller volumes in arteries and capillaries

Venous return

Muscle contractions (acts as pumps) Venous compliance (less blood left in veins) Ventilation (pump) Gravity (we're not going to talk about this)

Capillary network

Muscular arteries branches into aterioles which branch into capillaries - step in arterioles branching into capillaries Blood flows from arterioles through metarterioles, then through capillary network Flow through thoroughfare channel fairly consistent while flow through arterial capillaries is intermittent Smooth muscle in arterioles, metarterioles, precapillary sphincters regulates blood flow Diffusion into and out of capillaries moves substances throughout the body. Blood flows from arterioles through metarterioles, then through capillary network Blood flows to arteriole end of cap bed and BHP and TOP are going to cause fluid to leave cap bed and go into tissues Venule side of cap bed - where have THP and BOP causing fluid to move from tissues back into venule side Flow through thoroughfare channel fairly consistent while flow through arterial capillaries is intermittent Smooth muscle in arterioles, metarterioles, precapillary sphincters regulates blood flow

Arteries of upper limb

Need to know: Subclavian, axillary and brachial - are continuous tubes/blood vessels from subclavian to arm and do have branches of brachial artery Are the 3 continuous blood vessels of the arm in correct anatomical order Identifying things go back to anatomical position Continuous tubes from subclavian - turns into axillary artery when in armpit which then flows into the brachial artery lot branches in the arm because have collateral circulation in arm; damage to one part can still have blood flow there; have multiple ways of getting blood into your arms Subclavian artery and axillary - shoulder, chest, and back Brachial artery - arm

Fluid exchange across capillary walls

Net filtration pressure (NFP)

Venule end of cap bed

Net movement of tissues into cap bed Due to BHP and TOP on arteriole end losing water so becoming more concentrated creating osmotic pressure so BOP pulls interstitial fluid out tissue into venule end cap bed Also have fluid accumulating tissues - creates more hydrostatic pressure that pushes fluid into venule end cap bed THP - pushing fluid into venule end - and BOP - pulling fluid into venule side of cap bed THP =

Continuous

No gaps between endothelial cells. No fenestrae. Less permeable to large molecules than other capillary types. E.g., muscle, nervous tissue. Simple squamous epithelial cells do not have pores or gaps/fenestrae No gaps in epithelial cells Found in tissues where not a lot exchange of things so have them in muscles and nervous tissue - exchange gases and nutrients but not producing really big molecules in tissue or big molecules do not need to go to tissues; want to carefully regulate, blood-brain barrier, what goes into and out NS - NS gets damaged then not repaired Muscle tissue - very little repair; 1-1.7% can be prepared so sig damage to muscle or NS tissue is prob So want carefully regulate it

Blood entering the hepatic portal vein is rich with nutrients collected from the intestines, but may also contain toxic substances. Both nutrients and toxic substances will be regulated by the liver

Nutrients: Biotransformation:

Arterioles

Ole - means small Smaller arteries From muscular arteries to here Transport blood from small arteries to metarterioles, middle set of Arterioles, to capillaries Transport blood from small arteries to capillaries Smallest arteries where can differentiate the three tunics Metarterioles and arterioles cannot see the three layers Lot smooth muscle too and capable of a lot vasoconstriction and vasodilation Once at tissue site, arterioles kick in and really regulate pressure within tissues Too low not enough blood in tissues Too high pressure is an issues - too much hydrostatic pressure, pressure pushing blood into tissues, going to have have accumulation fluid - edema; time stays means amount fluid accumulated Careful regulation of fluid into tissues - want this Like small arteries, capable of vasoconstriction and dilation Arterioles regulate pressure through tissues Lead to capillaries

Vessels of penis and clitoris innervated by parasympathetic

One major exception in body - blood vessels in genitalia For sexual stimulation to occur also have to have some vasodilation; Erection - vessels have to vasodilate Erecetile Disfunction - related to blood vasculature and probs and increasing vasodilation and vasoconstriction changing those can affect cardiac effection

Other long-term mechanisms for regulating BP

One major things for long-term systems is see a lot of management of blood volume; increase volume present in circ system increases pressure Fluid shift: Stress-relaxation response:

Diffusion into and out of capillaries moves substances throughout the body.

Out on arteriole end and in on venule bed blood through metarteriole and maintain steady flow through channel and then pass through sphincter on arteriole end capillary bed which flow into venous capillary bed then into venules; smooth muscle in arterioles, metarterioles, precapillary sphintcters regulate blood flow going into tissues - diffusion out of blood on arteriole end and into on venules capillary end

Sounds due to turbulence not normal in arteries and is probably due to some constriction; increases the probability of thrombosis

Outside using tool for BP but one things can also occur when have disruption of flow moving to turbulent is you can trigger thrombosis/blood clot/clotting - turbulent flow can be translated biochemically as diamage and cause fibrinogen turn into fibrin and can produce a blood clot Really long international flight - do not sit still too long because sit still too long compression triggered thrombosis which can then move to heart or lungs and kill you

Hydrostatic pressure:

Physical pressure of blood flowing through the vessels or of fluid in interstitial spaces Physical pushing pressure Determined by:

BHP = blood hydrostatic pressure (or capillary filtration pressure)

Physical pressure of blood in blood vessels

Muscle contractions (acts as pumps)

Physically walk or move, leg muscles and abdominal and back contracting - contractions of skeletal muscles presses on the veins helping the return Not able walk - may have accumulation of fluid from lower limbs One mechanisms of getting fluid back to heart

Interrelationships between

Pressure Flow Resistance

Critical closing pressure:

Pressure at which a blood vessel collapses and blood flow stops Yes blood has to flow if not enough blood flow going through vasculature blood vessel can collapse - vessels are not like pipes in plumbing that never bend vessels are soft human tissue, pressure drops too low in vessel it can collapse

THP = tissue hydrostatic pressure (interstitial fluid pressure or IFP)

Pressure in tissues - sprained ankle and swelling - accumulating fluids in interstitial space around those tissues for variety reasons - it does not feel great because increasing pressure and triggering pain receptors and in some cases potentially compressing some nerves - accumulating more fluid in tissues - there is a limit to how much tissues can expand; glass full water flows out; no more space so have pressure pushing the water out - tissues are the same; outside brain/head, can accumulate some fluid; head, brain tissue, no room for accumulating fluid and once past that compressing cerebral tissue - cerebral edema and it is very serious

Short-term regulation of BP

Pretty fast and pretty quick Baroreceptor reflexes: Chemoreceptor reflexes:

Liver disease resulting in fewer plasma proteins

Producing fewer plasma proteins so blood less concentration and shift in movement

BCOP or BOP = blood colloid osmotic pressure/Blood osmotic pressure

Reference to the osmotic pressure: solute concentrations in blood

Resistance = 128vl/pD^4

Resistance in regards to fluid - very sig thing in vasculature - not able redesign arteries - can affect vasoconstriction and dilation p = pie Resistance is a very sig factor in blood vasculature, architecture is set, not going to be able to redesign arteries - it is what it is; can affect are things like vasoconstriction and vasodilation - peripheral resistance - can effect that Increase resistance when viscosity increases (viscosity is stickiness; stickier) - increase stickiness increase resistance of flow; vinegar less sticky than honey because honey is more viscous viscosity relates to blood - hematocrit - how much water is present in blood with ratio of water to ratio of RBC Length affects resistance - not something cannot change without big accident or sig surgery; length of blood vessels if fixed via development Diameter of blood vessel Resistance of blood flow - v is viscosity, l = length of the vessel, D is the diameter of the vessel Increase viscosity increase resistance Decrease diameter increases resistance and vice versa

Systemic circulation: veins

Returning blood from body to right atrium Carrying oxygenated blood from LV out to rest of body; systemic circulation also getting water out to all tissues; get water into body by drinking it; way get all macronutrients need to consume them (water, carbs, AA, lipids) have to consume them - digestive system is where go into then move across epithelial tissue and then go into circ system - heart pumping out O2 and water and nutrients that tissues need throughout body Major veins Types of veins

Major veins

Returning deoxy blood to RA Coronary sinus (heart) Superior vena cava Inferior vena cava

Pulmonary circulation

Right side heart going out to the lungs From right ventricle into pulmonary trunk Pulmonary trunk divides into left and right pulmonary arteries to lungs. Two pulmonary veins exit each lung and enter left atrium

TCOP or TOP = interstitial (tissue) colloid osmotic pressure (ICOP)/tissue osmotic pressure

Same thing in tissues Solute concentration present in the interstitial fluid surround cells and tissues

BP decreases

Secrete more ADH which vasoconstrict vessels and reabsorb more water in kidneys putting more water back in blood increasing blood volume; secrete renin then converted to aldosterone which then acts on kidneys to reabsorb more water and putting more water back into blood increase volume, angiotensin II, increasing vasoconstriction and PR and secrete less ANH secretion so reabsorbing more water back into blood increasing blood volume, increasing vasoconstriction and BP

Arteriole end of cap bed

See assuming everything working properly want fluid moving out of the arterile- cap bed into tissues - two pressures contribute to this directionality BHP - TOP - Arteriole end have a net movement from caps into tissues due to two forces: BHP - pushing fluid into tissue - and TOP - pulling fluid into tissues Net movement out on arteriole end

Degenerative changes (arteriosclerosis, atherosclerosis, etc.)

See this with aging in blood vasculature

short-term and long-term

Series of systems to regulate MAP - divided into quickly/short-term or long-term Short-term - seconds to minutes Long - minutes to days

Arteries of the head and neck

Side view - Brachiocephalic that branches into right common carotid and right subclavian; 3 branches off of the aortic arch Humans not symmetrical in chest even though think are Need to know - Brachiocephalic, R Subclavian, R common carotid, Left Subclavian, Left common carotid

2. Constriction of precapillary sphincters Precapillary sphincters contract as the tissue concentration of nutrients, such as O2 , glucose, amino acids, and fatty acids, increases. The sphincters also contract as the tissue concentration of metabolic by-products, such as CO2 , lactic acid, adenosine, adenosine monophosphate, adenosine diphosphate.

Sig long-term control where build more caps - body responding to tissue that need more blood vessels and generate more caps

Medium or large veins

Small to Medium feeds into large Largest veins back to heart are SVC and IVC All three tunics are present; tunica media thin but can regulate vessel diameter because blood pressure in the venous system is low; predominant layer is tunica adventitia

or medium arteries

Smooth muscle allows vessels to regulate blood supply by constricting or dilating Most of the smaller unnamed arteries muscular arteries Thick walls due to 25-40 layers of smooth muscle. Since have more smooth muscle Also called distributing arteries because smooth muscle vasoconstrict and vasodilate to control blood supply; all part of regulating blood supply to tissues different regions of the body; smooth muscle constricts and dilates to regulate blood supply to tissues

Protein starvation

Someone getting appropriate amount calories/nutrients and not enough proteins - are thin and have extremely rounded stomach - due to accumulation of fluid in abdomen because of protein starvation

Viscosity

Stickiness of fluid Measure of liquid to flow Blood is stickier and viscosity increases, pressure to make it flow increases Do not want blood to stop flowing - need it to get to tissues If having increased viscosity - to keep blood flow up heart responds by increasing HR and SV because flow proportional to pressure and inversely proportional to resistance; resistance goes up because viscosity gone up heart is going to have pump harder to pump blood; get blood to flow have to increase pressure; maintain same level of blood flow have to increase pressure Do not want flow to change so only way to respond to increased viscosity is to increase blood flow Hematocrit - Measure of resistance of liquid to flow Resistance proportionate to flow As viscosity increases, pressure required to flow increases Viscosity influenced largely by hematocrit (percentage of the total blood volume composed of red blood cells). Dehydration and/or uncontrolled production of RBCs can lead to increased viscosity which increases the workload on the heart. Remember hematocrit from CH 19

Large veins.

Still have not lot elastic fibers, have smooth muscle but that CT is going to be the predominant layer - not special muscle in veins as do arteries Tunica intima is thin: endothelial cells, relatively thin layer of C.T and a few scattered elastic fibers. Tunica media has circularly arranged smooth muscle cells. Adventitia is predominant layer.

Laminar flow

Streamlined; interior of blood vessel is smooth and of equal diameter along its length Outermost layer moving slowest and center moving fastest Nice, slow, streamlined No random movements or chaos of flow in blood Ideal - want this flow Nice and smooth

MAP between systolic and diastolic

Systolic - heart contraction Diastolic - heart relaxing

Veins:

Take blood back to heart - heart central pump; arteries to capillaries to veins thinner walls than arteries, contain less elastic tissue and fewer smooth muscle cells Structurally diff from arteries Thinner walls, less elastic tissue and less smooth muscle Less elastic tissue and less smooth muscle Venules Small veins Medium or large veins

BP taken

Taken in brachial because at same level of aorta and really want know where BP highest - aorta - closest to aorta Put BP cuff on brachial artery - technical term sphygomometer - happens is inflate until it compresses the brachial artery and inflated cuff and compressed brachial artery and then you slowly let pressure off the cuff and with stethoscope listen for sounds Sev stages of Korotkoff sounds but we care about 2 - onset of pushing/tapping - the first tapping or pushing sound is heart at regular interval - systolic BP; sound disappears - diastolic BP Systolic - BP in the brachial artery when heart is contracting/LV contraction; diastolic BP - pressure in brachial artery when LV relaxing/during diastole Unit of BP - mm Hg or millimeters of Mercury - done in past; it is both units Systolic pressure - top number; tells number of mm Hg in this section Diastolic - lower number; tells number of mm Hg in this section

Vascular compliance:

Tendency for blood vessel volume to increase as blood pressure increases Compliance - the amount of blood the blood vasculature can hold Veins have higher compliance than arteries because under lower pressure and bulge more and able to expand little more

Diameter:

The width of the blood vessel. As diameter increases, resistance decreases and vice versa

Approximately 70 mmHg at birth, 100 mmHg from adolescence to middle age, 110-120 mmHg in healthy older individuals.

There is some debate about which number more imp in older individuals in terms of hypertension - systolic or diastolic - shifts; as of right now diastolic may be more imp in terms of hypertension treatments

Descending aorta

Thoracic aorta: Abdominal aorta:

Are a series mechanisms present to regulate MAP

Too low BP - fatal; are not able maintain pressure to move blood through circ system and not blood to vital organs including the brainstem that are necessary Too high BP in long term can be very serious; maintaining too much HP in blood vessels can damage caps; break damaged caps and hurt tissue is a happy medium - regulate BP, not like pH where regulate narrowly - BP if running for your life - high BP is necessary - want BP go up in that scenario but if resting needs go down; BP shifts based on environmental conditions; one reasons why high stress increases BP because increases sympathetic stimulation of blood vessels; stress linked to high BP; want BP to be appropriate to situation

Cross-sectional area

Total amount area covered by blood vasculature vs flow rate - velocity of blood flow - how fast blood is moving Most cross-sectional area in capillaries because they are branching out trying to get blood flow to your tissues Flow rate - highest in the aorta, drop off and slow to capillaries and pick up as increase diameter in blood vessels as go back to heart Aorta - large diameter and high pressure and not much resistance; move oxy blood out quickly to get it out to body so large diameter and high pressure Capillaries - blood slows down; exchange in capillaries have lots SA and lots of vasculature, very slow, on arteriole end of capillary bed dropping of oxygen and venous picking up CO2 then speed up as return back to heart - increase diameter and increase pressure As the diameter of vessels decreases, the total cross-sectional area increases and velocity of blood flow decreases. Only one aorta with a cross-sectional area of 5 cm2. Total cross-sectional area of the millions of capillaries is 2500 cm2. Much like a stream that flows rapidly through a narrow gorge but flows slowly through a broad plane

Biotransformation:

Toxic substances can be broken down by hepatocytes or can be made water soluble. To be transported in blood and excreted by the kidneys. Importantly have this Taking Toxic substances and breaking them down by hepatocytes (cells in the liver) making them water soluble so can be transported in the blood and excreted by the kidneys - detoxification

Neural innervation of blood vessels

Unmyelinated sympathetic nerve fibers form plexi in tunica adventitia: vasoconstriction Vasoconstriction and vasodilation - smooth muscle very often has to have innervation by NS to constrict Blood vasculature has neural innervation: nerves innervating smooth muscle of blood vessels Organ not equally innervated by sym and para - sweat glands and Blood vessels - innervated primarily by sympathetic NS Unmyleinated sympathetic nerve fibers innervate blood vessels and causes vasoconstriction so stimulation causes vasoconstriction of blood vessels; increased epi released causing them to vasoconstrict Small arteries and arterioles in muscle have most sig amount of innervation to greatest extent Vessels of penis and clitoris innervated by parasympathetic Blood vasculature and sweat glands sympathetic stimulation with exception of genitalia need vasoconstriction Some blood vessels innervated by myelinated fibers and act as baroreceptors that monitor stretch and detect changes in blood pressure

Valves

Valves found in all veins greater than 2 mm in diameter. Unique to veins and not present in arteries Similar to SL valves Have cusps - blood pushing up and opens the cusp of blood and get backflow valve closes and snaps shut - not 100% - varicose veins part of that is that there are stretching veins and now valves will not come closed so now blood will pool See lot more valves in lower extremities because further from the heart so backflow is a bigger issue Folds in intima form two flaps that overlap. More valves in veins of lower extremities than in veins of upper extremities. Folds in tunica intima form the valves of veins, which allow blood to flow toward heart but not in opp direction

Blockage of veins increases capillary BP; reduced venous return due to gravity

Veins are blocked have back flow which increase papillary BP and reduce venous return

Functional characteristics of veins

Venous return to heart increases due to increase in blood volume, venous tone, and arteriole dilation Return blood to heart - venous return is the amount of blood going back to heart Increase with venous return

Flow:

Volume per unit time. E.g., Amount of blood moving from point A to point B per minute.

Blood not over react to increased O2 levels but a decrease CO2 decreasing H+ making more alkaline (more risk for alkalosis)

Want get less blood out to lungs and breathe out less CO2 so decrease PR and increase vasodilation so leaving more blood in tissues and less blood back to heart Want pump less blood out to lungs so decrease HR and SV Only thing adding is PR

Not enough O2

Want to get more blood back to the heart do that by increasing vasoconstriction increasing PR and leaves less blood in tissues and gets more blood back to heart and more venous return; want get more blood back to lungs by increase HR and SV; more O2 from lungs back to blood to rest of body - increase HR and SV

Control mechanisms that regulate blood pressure and blood flow

Ways body can control diff factors - some factors can be controlled and some not Architecture of blood vasculature is fixed unless have damage or surgery - it is what it is

Flow =(P1 -P2)/R = p(P1 -P2)D4/128vl

Ways increase blood flow - Decrease flow Viscosity relates to this/factors into this Relationship between pressure, resistance, diameter, viscosity to flow Flow - volume per time not pressure

Tissues -

Whole bunch cells surrounded by interstitial fluid; could be any type of tissue; have a capillary bed with an arteriole end and venule end; movement of blood through arterioles to metarterioles through thoroughfare channel through cap bed passed cap sphincters to arteriole and to venous end to venules

Increased CO2 concentrations in blood

Will increase H+ concentration in blood Want to bring both down to decrease H+ concentration; get more blood out to lungs to breathe out more CO2 - leave more blood in veins increases compliance and increases blood in tissues and picks up more CO2 and not offloading CO2 to lungs; increase PR increases venous return get more blood from body back to the heart Get more blood out to lungs so breathe out more CO2 Increase HR and SV

Blood CO2 concentrations have decreased.

[H+] has decreased. Blood pH has increased. - alkaline To return to physiologic pH, heart rate, SV, and PR will be decreased. blood vessels will be vasodilated. Decrease MAP/BP Leave more CO2 in blood so want it produce more H+ ions Pumping less blood out to lungs; PR - vasodilate the blood vessels in tissues so leave more blood in tissue and pick up more CO2 because tissues constantly releasing CO2 as a byproduct of aerobic respiration; vasodilation - more blood in tissues and less blood back to heart; dilate - decrease PR leaving more blood in tissues

Blood CO2 concentrations in the blood have increased.

[H+] has increased. Blood pH has decreased. - acidic To return to physiologic pH, heart rate, SV, and PR will be increased and blood vessels will be vasoconstricted because increases PR Increases BP Contract more often to get blood to lungs and increase force heart contracting pushing more blood to lungs; increase PR - vasoconstrict circ system leaving less blood in tissues and more blood to heart; gets more blood back to heart; increase MAP/BP Increase constriction increases PR and leave less blood tissue increasing PR; relates to leaving blood in tissues

Stress-relaxation response:

adjustment of blood vessel smooth muscle to respond to change in blood volume. When blood volume suddenly declines and pressure drops, smooth muscles contract and vice versa. Long-term mechanism References constriction of blood vasculature - that tunica media - smooth muscle inside blood vasculature Happen is each cell has blood volume suddenly declines and pressure suddenly drops, happen is you are going to vasoconstrict smooth muscle so raise BP at min; BP too low not enough blood flow to brain and when that happens pass out Can have opp blood volume too high - BP increases enough have smooth muscle relaxation and vasodilation

Peripheral circulation

aka vascular system aka blood vessels which transport blood through the body; with the exception spleen or if had damage to the body, blood does not leave the circ sys; blood moving through body it is staying in these tubes/blood vessels; bruise: broken some blood vessels and now blood accumulating outside of circ system; internal bleeding - damaged blood vessels and bleeding into internal body cavities; spleen diff - there have RBC leaving circ system and getting filtered; blood does not leave circ system unless there is an issue

causes ↑ reabsorption of sodium and water by the kidneys and effect on BP

aldosterone only causes increases in sodium and water reabsorption Does not cause increased vasoconstriction Regulates K+ as well Increases BP

Which of the following chemical substances, when released into the blood, would cause blood pressure increase

angiotensin II (active angiotensin) - increases vasoconstriction and increases production aldosterone aldosterone - increases blood reabsorption in kidney increasing blood volume and increasing BP ADH aka vasopressin - increase vasoconstriction and increases MAP; increase water reabsorption in kidney increasing blood volume and increasing BP

causes ↑ water in the urine; increase water concentration in urine and effect on BP

atrial natriuretic hormone (ANH) decreases BP

Which of the following chemical substances, when released into the blood, would cause blood pressure to decrease?

atrial natriuretic hormone - it decreases the actions of ADH and decreases aldosterone; increases water going into the urine so decreasing reabsorption in kidney so excrete more water lowering blood volume and lowering BP

Dynamics of blood circulation

blood circulation - there is an interrelationship between 3 things Interrelationships between Control mechanisms that regulate blood pressure and blood flow

Both hydro and osm both for

blood fluid and interstitial fluid in tissues and that filtration pressure dictates what the direction is

Vasa vasorum:

blood vessels that supply the walls of arteries and veins. Penetrate vessel walls from the exterior. Branches of arteries. Arteries and veins have blood going through them at a relatively high speed for the best possible exchange of materials in tissue need it to be slow; just like going through drive through Blood through arteries and veins too quickly for exchange to take place so have these, which are special blood vessels that branch off major arteries and veins, that then take oxygenated blood to epitheial and CT of major blood vessels and take deoxy blood away from them; materials to there; typically deoxy going back into regular blood flow

Resistance of blood flow -

body are affected by viscosity, how sticky blood is which is determined by RBC and hydration diameter of blood vessel - how much constriction or dilation present

ADH and RAAS -

both cause increased vasoconstriction and water reabsorption

Long-term local control:

capillaries become more dense in a region that regularly has an increased metabolic rate.

Baroreceptor reflexes:

change peripheral resistance, heart rate, and stroke volume in response to changes in blood pressure Have mechanoreceptors that detect increased stretch in aorta and carotid arteries; they will affect HR and SV and PR in response to changes in BP; BP suddenly drops trigger this reflex increasing vasoconstriction and increase HR and potentially SV and increase BP Para and symp innervation of heart; only sym innervation of the blood vessels BP too high BP too low Baroreceptor reflex control Adrenal medullary mechanism

Tunica externa (adventitia):

connective tissue, varies from dense regular near the vessel to loose that merges with the surrounding C.T.

Turbulent flow

constrictions of tube will cause turbulent Constriction of tightened tube or blood vessel will cause turbulent flow Interruptions to flow Causes fluid to become more chaotic and changes way moving Partially responsible for heart sounds hear = can hear blood moving through heart and part that is valves closing and some turbulent flow because large chamber doing large chamber to another large chamber so as move from atrium to ventricles have this Constriction and causes blood to no longer be smooth Interrupted Rate of flow exceeds critical velocity Fluid passes a constriction, sharp turn, rough surface Partially responsible for heart sounds Sounds due to turbulence not normal in arteries and is probably due to some constriction; increases the probability of thrombosis

Decrease flow

decrease pressure and increase resistance and decrease diameter

Decrease CO2

decreases HR

Atherosclerosis:

deposition of plaque on walls Specific deposition of plaque in walls of vessels narrowing channel and increasing risk for blood clots

BHP -

due to pumping of heart have more physical force pushing fluid out - fluid inside caps its plasma but when it moves into tissues it is interstitial fluid; BHP pushing fluid out of arteriole end of capillaries fluid movement out of arteriole end is carrying water, O2, glucose, AA; movement into tissues

Nutrients:

either taken up and stored or modified chemically and used by other parts of the body Liver also does imp things like takes up nutrients - part regulation of blood glucose involves glycogen broken into glucose released into circ system to maintain blood glucose levels constant and below 50 mg/dL = fatal; 70-140 right after eating and if not eaten in awhile 70-110; do not want to get too low; liver stores nutrients

Aorta

exits left ventricle and is divided into three parts Divided into 3 parts Leaving LV Aorta - large artery leaving heart; taking oxy blood from systemic side circ from LV out to body In generally humans biologically symmetrical; most major exception is chest and abdomen; to most efficiently fit material into limited space not going to have symmetry - in generally yes are symmetrical, split down middle and matches right and left but this is major exception Not all human body is bilaterally symmetrical - tend to think this; means cut right down middle and have matching halves; are symetrical and exactly sim Not case for abdominal and thoracic cavities - particularly the blood vessels in thoracic cavity/chest; complex animals/mammals see asymmetry in chest - idea is can pack more material in chest but the take away this is not symmetrical Ascending aorta: Aortic arch: Descending aorta

Blood

fluid moved through CV/circ system

Net filtration pressure (NFP)

force responsible for moving fluid across capillary walls. Two forces affect pressure Forces that are responsible for moving fluid across capillary walls Want fluid to move out capillary walls on arterial sides and into venous side 2 forces that affect this Hydrostatic pressure: Osmotic pressure:

Arteriosclerosis:

general term for degenerative changes in arteries making them less elastic Generic change for degenerative changes in smooth muscle, CT, epithelial tissue that take place in the arteries and makes them less elastic

Increase level of O2

high levels O2 do not need to get more blood to lungs for oxygenation so not increase HR

2 portal systems in body:

hypothalamhypophysial portal system - between hypo and AP, connects cap beds in hypo to cap beds in AP digestive system and liver = hepatic portal system - connect cap beds in intestines to cap beds in liver - liver serves as major detoxifier of the material consume; why people consume large amounts alcohol or makes you high is toxin is body metabolizing a toxin; you consume things and potentially a lot toxins in it so want detox that material before goes in circ system; so blood near the intestines (capillaries in intestines) and material diffuses from inside intestines and pass epithelial tissue into circ system but before start pumping that to rest of body goes liver where detox and then goes into VC and then pumped into the blood

Identify the direction of flow (in or out of tissues) caused by each fluid pressure: Blood Hydrostatic Pressure

in tissues

Identify the direction of flow (in or out of tissues) caused by each fluid pressure: Tissue (colloid) Osmotic Pressure

in tissues

Increase BP

increase HR keys increase BP - but not healthy response

Diameter of blood vessel

increase diameter decrease resistance and vice versa smooth muscle present in blood vessels which can constrict to decrease diameter and dilate to increase diameter

Compliance =

increase in volume/Increase in pressure More easily the vessel wall stretches, the greater its compliance Venous system has a large compliance (24 times greater than that of arteries) and acts as a blood reservoir Practically means vessel wall stretches greater compliance Direct application -

Increase level CO2

increases HR

Abdominal aorta:

inferior to diaphragm. Ends as two common iliac arteries Dorsal blood vessel and nerve cord as opposed to ventral; run towards back of the body thens split into right and left common iliac arteries

The pressures that move fluids

into and out tissues/capillaries; moving out cap then into tissues; moving into cap then moving out tissue - working in opposition to eachother

Blood osmotic pressure is primarily responsible for moving fluid

into the venule side of the capillary bed

Tissue hydrostatic pressure is primarily responsible for moving fluid

into the venule side of the capillary bed

Heart

is the pump

Heart ->

leads to Elastic arteries → that branch into muscular arteries → that branch into arterioles → that branch into capillaries → then fuse into venules → fuse into small veins → fuse into med that fuse into large veins and return blood back to the heart

Hepatic portal-

liver; hypothalamohypophyseal portal between hypothalamus and pituitary. Blood from intestines to the liver for detoxification All cap beds in intestines and this is where you are getting water, ions, glucose, AA, cholesterol, lipids, triglycerides/triglycerols All things consumed go into tube of digestive system and then broken down, external digestion where occurs outside body - not in tissues, and broken and absorbed across epithelial tissue that then goes into circ system - want make sure that material cleaned up and detoxed before going to the rest of body - not 100% but outside of extreme circumstances take blood to the liver and detox it; then nutrient rich, oxygen poor detox blood returns to vena cava to go back to heart Water consume moves through epithelial tissue in digestive system in multiple locations; getting water through circ system from digestive system; intestines - are getting carbs and AA going to liver and then detoxifying them then to IVC and return back to heart and now nutrient-rich, O2-poor blood pumped to lungs to pick up oxygen then oxygenated and nutrient rich blood from LV; that is hepatic portal system; lipids later on

Fluid shift:

movement of fluid from interstitial spaces into capillaries in response to decrease in blood pressure to maintain blood volume and vice versa. Another long-term system A fluid moving - have movement of fluid from interstitial spaces (cells are aquatic - have to be surrounded by aqueous environment of interstitial fluid) - can have if sig decrease in BP - can happen is fluid can move from interstitial spaces into the vasculature which then increases blood volume and thus increases BP Having sig high BP can end up having fluid moving from the interior of the blood vessels into interstitial spaces - along with CV probs related to high BP, mechanism also one reasons see accumulation of fluid - edema - in tissues as a response to chronic high BP

Osmotic pressure:

movement of solutes (plasma or tissue fluid) through a membrane (plasma membrane) in the presence of a non-diffusible solute (large proteins). Large proteins do not freely pass through the capillary walls and the difference in protein concentrations between the blood and interstitial fluid is responsible for osmosis Chemical pressure - walking towards the smell of cake Osmosis - chemical pressure moves water across the semipermeable membrane Chemical pulling Determined by

Hematocrit -

one sig indicator of viscosity - mainly influenced by hematocrit; influenced by dehydration and uncontrolled production of RBC percentage of total blood volume of complete RBC More RBC is not better Physiology loves happy mediums Too many - sig increasing viscosity of blood thus increasing how hard heart has to work causing heart damage Too little - too little oxygen Dictated by hydration - blood 55% plasma - 91% water and unctrolled production RBC - can sometimes go wrong; uncontrolled issues of EPO; as increase in altitude because less oxygen/unit area because of pressure difference in altitude going to increase EPO - common in climbers in 30s and up to aspirin constantly because of anticoagulation effects because hematocrit too high Dehydration and increased RBC increases work of heart because blood to flow Extreme altitude impacts it; need to be able to transport enough oxygen; less oxygen produced more EPO Highly trained and high quality to have heart attacks at high altitudes

Tissue osmotic pressure is primarily responsible for moving fluid

out of artial side of the capillary bed

Blood hydrostatic pressure is primarily responsible for moving fluid

out of the arterial side of the capillary bed.

Identify the direction of flow (in or out of tissues) caused by each fluid pressure: Blood (capillary colloid) Osmotic Pressure

out tissues

Identify the direction of flow (in or out of tissues) caused by each fluid pressure: Tissue Hydrostatic Pressure

out tissues

Vasomotion:

periodic contraction and relaxation of precapillary sphincters. Feature of autoregulation. Ensuring pushing blood through cap beds Sig increase in metabolic needs - increase cap deposition in those tissues

Thoracic aorta:

portion in thorax Thorax or chest Diaphragm base of this cavity/lower point

osmosis

refers to movement of water - moves down its concentration (high to low water concentrations but because solvent whose are main features of biochemical rxns of life only talk about it in terms of solute); so water moves from area of low solute to high solute concentration

flow Indirectly proportional to resistance

resistance is the amount of force that opposes blood flow; Decrease resistance increase blood flow and vice versa

Nervous System:

responsible for routing blood flow and maintaining blood pressure NS is responsible for vasoconstriction and dilation of arteries and veins and the precap sphincters - NS controlling dilation and constriction of those Imp for routing blood flow and maintaining BP Pressure and flow are diff; pressure - force/physical pushing on blood vessel/unit area; flow - amount of fluid moving through a specific space/unit time; increase pressure may decrease the amount of blood in a particular blood vessel because vasoconstricting; so going to use NS to regulate vasoconstriction, regulate diameter of blood vessels, which will regulate BP Responsible for maintain BP along with SA node and also have NS increasing or decreasing stimulation of heart Flow - amount fluid moving in unit space per unit time Important in minute-to-minute regulation of local circulation Primarily blood vessels; increase sympathetic stimulation that causes in gen fair amount of increased vasoconstriction - depends tho on adrenergic receptor Respond to tissue needs with dilation or constriction - primary way in which vessels innervated is sym NS; except for vessels in clit and penis - para NS because dilation is necessary for them Provides a means by which blood can be shunted from one large area of the peripheral circulatory system to another area by increasing resistance

Ascending aorta:

right and left coronary arteries branch from here Very first part of aorta Means it is going up/ascending Very first branch is right and left coronary arteries then arches over Right and left coronary arteries immediately branch and take oxy blood to cardiac tissue First branching of aorta are right and left coronary arteries

Two systems to regulate pressure:

short-term and long-term

Capillaries:

site of exchange with tissues Where have exchange - get fluid, nutrients, waste products into and out of tissues Many so small that only couple RBC can get through at a time; very small Branching out and going into the tissues These will then fuse into veins; first fuse into venules Arterioles to capillaries Nutrients, ions, carbs, lipids, AA, micronutrients (Ca, Na) going into tissues Where have exchange Water going into tissues and oxygen going into tissues and ions, nutrients, macronutrients (carbs, lipids, AA), micronutrients (Ca, Na, K) going into tissues Going to have waste products going out Water-solube or lipid-soluble really dictates how it is going to go into tissue See have capillary wall have thin epithelial cells: thin simple squamous epithelium - free side is to the internal/inside; basement membrane - present Almost all epithelial tissue has a basement membrane except epithelial tissue in lymphatic sys Some capillary cells that can form fibrous tissue: fibroblasts and some macrophages and little undifferentiated smooth muscle - capillaries are made Lipid-soluble molecules can easily diffuses across plasma membrane into simple squamous epithelium in capillary through basement membrane into tissues - releasing steroid it can easily cross plasma membrane of cap beds; really small molecules, like O2 and CO2, easily diffuse; water-solube (water and proteins) have to think about how get those into tissues - do that structurally by diff type capillaries - named based on size of pores Capillary wall consists of endothelial cells (simple squamous epithelium), basement membrane and a delicate layer of loose C.T. Scattered pericapillary cells that are fibroblasts, macrophages or undifferentiated smooth muscle cells. Substances move through capillaries by diffusion:

Tunica media:

smooth muscle cells arranged circularly around the blood vessel. Middle layer Lot smooth muscle - can vasoconstrict and vasodilate Vasoconstriction: Vasodilation: Diameter of vessel determines how much volume of blood is present and influences BP

Vasoconstriction:

smooth muscles contract, decrease in blood flow (Volume/time) Making diameter of tube smaller decreasing amount blood present/decrease volume per unit time but increases BP Less blood leave tube but leaving with greater force because of vasoconstriction Make diameter smaller

Vasodilation:

smooth muscles relax, increase in blood flow (volume/time) Making diameter of tube larger Means more blood per unit area per time but it is going to decrease BP - BP is force on the walls of blood vessel; more bigger and more space means less compression More volume per unit time More blood out

Hormonal Control:

sympathetic action potentials move down SC and then go into adrenal medulla of adrenal gland stimulate release epinephrine and norepinephrine Hormones Epi = depending on location can cause vasoconstriction or vasodilation; type adrenergic receptor dictates response to epi or nor Coronary arteries and skeletal - dilate Constrict - in blood vessels in GI system because more out to heart, muscles, and lungs; less to rest and digest Depend on adrenergic receptor

Capillary exchange:

the movement of substances into and out of capillaries Moving stuff/substances in and out of capillaries

layers of arteries and veins

tunica intima, tunica media, tunica externa

Portal system:

vascular system that begins and ends at a capillary bed with no pumping mechanism in between. Two cap beds connected by vessel and no pump

Portal veins:

veins that begin in a primary capillary network, extend some distance and end in a secondary capillary network without a pumping mechanism, such as the heart, between them. A vein that connects two capillary beds with no pump Heart - connection; heart, arteries, capillaries, lungs, veins, back to heart Have two capillary beds and no pump; portal vein connects from one capillary bed to another one 2 portal systems in body:

Direct application - (Compliance =)

venous system, veins, have greater compliance so they serve as a blood reservoir - venous return now factoring into CV functioning; low venous return meaning have high compliance so have more blood in veins and less blood to heart Decrease compliance, return blood back to heart increased venous return Starling's law of preload - more venous return means more stretch cardiac tissue and more contractions

Regulation =

want blood to flow to body and want be able to control the flow and ways regulated it is regulating pressure and volume

Blood flow increases

when increase pressure Increasing HR and SV - force contractions increases pressure of blood leaving heart increasing flow decreasing HR and SV decreases pressure blood flow is inversely proporitional to resistance - increase resistance (diameter smaller) decreases blood flow; increase resistance by making diameter small - vasoconstrict and increase resistance and vasodilate, decrease resistance Talking about flow NOT PRESSURE - pressure very specific - force/unit area; volume that passes specific point/unit time - NOT PRESSURE Increase viscosity increases resistance Increase diameter decrease resistance and vice versa; gets larger this gets small and if this gets smaller this gets larger