Anat Lecture Exam 2 Prep:

Capilaries

- Tunica intima only w/ pericytes - w/ pericytes -Highly branched - great total length - very narrow - hi resistance * squeeze some - influences substances coming in andout - 1 cell layer thick -length 1 mm, highly branched, end to end 26000 miles no cells more than 2 to 3 cell lengths away from capillaries. * greatest vascular surface area, less resistance in larger diameter high

Blood Pressure Varies throughout vascular system

-Depends on: -compliance of vessel walls -distance from heart - Resistance * Pressure in vascular system BP -force of blood against blood vessel walls - things affect BP - stretchability of blood vessels - closer to walls or further (distances to heart) - Amt. of resistance - adjust diameter of tubes vasodialate/vasoconstrict - compliance w/ vessel walls= stretchability

Decrease Release of ANP

-Increase conservation of Na+ and water by kidneys -Increased blood volume -Increased venous Return -Increased Stroke volume -Increased cardiac output -Increased Mean Arterial Pressure (MAP)

Systemic BP-Veins

-Low venous pressure -No Pulsatile wave -but pressure gradient still exists *What are 3 modifications in venous system that help move blood through venous system? a)valves -prevent back flow b) peristallisis in (tunica media contraction) c) Respiratory pumps -diaphragm pulls down increasing pressure on thoracic cavity causing to move blood through venous system

Systemic BP- Arteries

-Map decreases with increasing distance from the heart -Pulse pressure decreases w/ distance from the heart -Blood always moves from areas of higher pressure to areas of lower pressure *still have a pressure gradient

skeletal muscle pump

-Muscle contractions squeeze veins - valves allow movement in only 1 direction (toward the heart) * use of muscles act to squeeze the veins - veins have valves that allow blood to squirt in one direction and have valves.

antidiuretic hormone (ADH)

-Produced by hypothalamus in response to low BP -causes kidneys to conserve H2O increase blood volume, increase BP (long term mechanism) -high levels stimulate vasoconstriction increase BP ***also called Vasopressin *low BP, pee less, increase blood volume, increase BP * High ADH if really low BP

Atrial natriuretic peptide (ANP)

-Released by atrial myocytes in response to atrial distension -promotes Na+ & H2O excretion by kidneys -results in decrease of blood volume & decerease BP (Kidney kick out more Na+ & H2O) -Also causes vasodilation resulting in decrease BP * High Blood volume =High BP = stretch out Atrial myocytes *High blood volume-drink more then decrease blood volume ANP= vasodilation -pee extra blood volume

Indirect Renal Mechanism

-Renin-angiotensin-aldosteron mechanism results in release of angiotensinII and stabilizes BP & Blood volume in several ways.

capillary slow flow

-The greater the total cross-sectional area the slower the blood flow - Each capillary is tiny but combined area is huge * allows ample time for diffusion of waste products in & out of blood in capillaries * velocity slows once inside capillaries * simple squamous epithelium -highly branched - no smooth muscles - pericytes cells - contractile - high resistance to flow - vary narrow - some - only 1 RBC can pass through at a time

Capillary structure

-Three types on structure of endothelium - continuous -fenestrated -lg. pores between the cells - sinusoidal: big gaps between adjacent cells, lg. molecules, no need vesicles (bone marrow, spleen, lymphnodes * structure dictates function - more gaps= more permeable *tight junctions - end up with clefts between cells - adapt for CNS - blood brain barrier - tight junction w/ endothelial cells - basement membrane, muco protein layer - restricts passage of some substances - few vesicles - absorption & filtration --> intestines, kidneys, endocrine.

Incrased vasomotor tone; bloodborne chemicals (epinephrine, NE, ADH, angiotensin II

-decreased diameter of blood vessels -increased peripheral resistance -increased Map

Crisis Stressors: Exercise, trauma, increased body temperature

-increased blood pH -decreased o2 -increased co2 -activation of vasomotor and cardioacceleratory brain centers in brain stem -decreased diameter of blood vessels -increased peripheral resistance -increased blood viscosity -increased blood vessel length -Increased Map

increased body size

-increased blood vessel length -increased peripheral resistance -increased map

Dehydration, high hematocrit

-increased blood viscosity -increased peripheral resistance increased Map

Resistance (peripheral resistance)

-measure of the opposition to fluid movement in CV system (peripheral resistance units) -friction of blood against vessel walls - Opposes blood flow * peripheral blood vessels calculated as affection flow. -Relative unit as oppose to something measure differently. -How much friction in vessel walls - lot friction will decrease flow rate.

Resistance (peripheral resistance)

-measure the opposition to fluid movement in CV system (peripheral resistance units) - Friction of blood against vessel walls - opposes blood flow **peripheral blood vessels calculated as affection flow. Relative unit as oppose to something measure directly -more friction = less flow rate

Baroreceptor Reflex (Inbalance High BP)

1) Stimulus: -Increase blood pressure (arterial BP rises above normal range) 2) Baroreceptors in carotid sinuses and aortic arch are stimulated 3) Increases impulses from baroreceptors stimulate cardioinhibitory center (and inhibit cardioacceleratory center) and inhibit vasomotor center 4a) decrease impulses to heart, cause decrease HR, decrease contractility and decrease CO 4b) decreased rate of vasomotor impulses alows vasodilation, causing decreased restriction (R= peripheral Resistance) 5) decreased CO and decreased R return BP to homeostatic range

baroreceptor reflex (Inbalance low BP)

1) Stimulus: -decrease blood pressure (arterial blood pressure falls below normal range) 2) ? in carotid sinuses and aortic arch are inhibited 3) decrease impulse from baroreceptors activate cardioacceleratory center (and inhibit cardioinhibitory center) and stimulate the vasomotor center 4a) increase sympathetic impulses to heart, cause increase to HR, increase contractility and increase CO 4b) vasomotor fibers stimulate vasomotor constriction causing increase in resistance (R) 5) Increase CO and increased R return blood pressure to homeostatic range.

Neural control of BP

1) The CV center receives sensory inputs from -Baroreceptors -Chemoreceptors -higher brain centers 2) CV center in medulla can modify CO & peripheral resistance -cardiac centers: carcioacceleratory (modify rate and force of hear contraction -vasomotor center (modify diameter of blood vessels)

Renin-Angiotensin system

1) kidney receptors detect low BP or are stimulated by the SNS division; renin enzyme is released 2) Renin converts angiotensinogen into angiotensin into angiotensin I. 3) ACE converts angiotensin 1 into angiotensin II 4) Angiotensin II increases BP by: -causing vasoconstriction -stimulating thirst center -decreasing urine information.

Chemoreceptors

1) located in aortic arch & large arteries of neck 2) Activated by low o2, low blood pH & high CO2 -Exercise, high metabolic demand 3) Stimuli sent to CV center, which modifies response to stabilize BP 4) When activated -cause cardiac output -vasoconstriction -increased respiration >>>? influence BP but play larger role in modification of respiration

High Brain Centers

1) not involved in routine BP regulation 2) But cerebral cortex & hypothalamus can modify BP via relays to CV centers 3 major influences in BP neural , hormonal, renal

Fetal circulation

1) oxygenated blood from the placenta enters the body of the fetus through the Umbilical vein 2) The blood from the umbilical vein is shunted away from the liver and directly toward the inferior vena cava through the ductus venosus 3) Oxygenated blood in the ductus venuosus mixes w/ deoxygenated blood in the inferior vena cava 4) Blood from the superior and inferior venae cavae empties into the R atrium 5) Because pressure is greater on the R side of the heart than on the left side, most of the blood is shunted from the R atrium to the L atrium via the foramen ovale 6) A small amount of blood enters the R ventricle and then the pulmonary trunk, but much of this blood is shunted from the pulmonary trunk to the aorta through a vessel detour called ductus arteriosus. 7) Blood is transported to the rest of the body, and the deoxygenated blood returns to the placenta through a pair of umbilical arteries 8) Nutrient and gas exchange occurs at the placenta.

Pathology of BP Regulation: hypertension

1) systolic > 120mmHg or diastolic >80mmHg 2) strains heart and damages arteries -heart wk. harder pushing blood, kidney failure, stroke , endocrine disease 3)May be due to underlying condition but often due to genetic and or environmental factor. -genetics, stress

Refer to the following equation to answer the following questions: resistance x (length of vessel X viscosity of blood)/radius of vessel ^4 Calculate the resistance using the data points below and the following equation : 32cm vessel length b) viscosity = 100 c) radius = 4mm

12.5

Refer to the following equation to answer the following questions: resistance x (length of vessel X viscosity of blood)/radius of vessel ^4 Calculate the resistance using the data points below and the following equation : a) 30cm vessel length b) viscosity = 100 c) radius = 2mm resistance =

187.5

Refer to the following equation to answer the following questions: resistance x (length of vessel X viscosity of blood)/radius of vessel ^4 Calculate the resistance using the data points below and the following equation : a) 32 cm vessel length b) viscosity = 100 c) radius =2mm Resistance =

200

Refer to the following equation to answer the following questions: resistance x (length of vessel X viscosity of blood)/radius of vessel ^4 Calculate the resistance using the data points below and the following equation : a) 32 cm vessel length b) viscosity = 102 c) radius = 2mm resistance =

204

vericose veins

? ? incompetent valves Risk factors: aging, genetics, obesity, pregnancy, obesity, pregnancy, standing or sitting still for long periods of time, diabetes damages vessel walls, cross legs make harder for blood to move back * compression : decreases swelling - keep fluid from flowing out of capillaries * valves are not working, blood can squirt the wrong direction * can damage the veins - if not using the vascular pumps ... standing long time gravity... blood - can't get back to heart - work against gravity to get back to heart. - pooling of blood in leg vein causing blood clots.

Vesicular transport

? ? occurs when endothelial cells use pinocytosis to form fluid-filled vesicles , which are then transported to the other side of the cell and released by exocytosis.

Bulk flow

? ? refers to the movement of large amounts of fluids and their dissolved substances in one direction down a pressure gradient.

hormonal controls

? ? regulate BP -short term: by altering peripheral resistance (i.e. vasoconstriction/vasodilation) -long term: by altering blood volume Several different hormones influence blood pressure, including: -norepinephrine & epinephrine -atrial natriuretic peptide -antidiuretic hormone - angiotensin

resistance

? also influences total blood flow and is defined by the amount of friction the blood experiences as it is transported through the blood vessels. -Blood flow is always opposed by resistance .

Hypertension/Hypotension

? is chronically elevated BP, defined as systolic pressure greater than 140 mmHg or diastolic pressure greater than 90mmHg. -may damage blood vessel walls, making arteries more likely to develop athersclerosis or the arteriole walls may become stiff or harden, a condition called arteriosclerosis. - ? also places an extra workload on the heart that may lead to congestive heart failure. ? is a chronically low BP that results in symptoms such as fatigue, dizziness, and fainting. systolic below 90mmHg or DP below 60mmHg. Orthostatic hypotension is a drop in BP when an individual suddenly changes position, as when a person stands up after lying down. As a result the person may experience dizziness, light-headedness, and fainting after this positional change. -nervous system responses that help regulate BP do not respond quickly enough and MAP temporily decreases below 60mmHg. Thus blood remains pooled in veins and not enough reaches the cerebral vasculature.

Vasodialation/vasoconstriction

? of arterioles results in more blood flow to capillaries serving cells - less blood flow through capillaries -blood vessels to gut-vasoconstrict -blood vessels to leg vasodilate -sphincter helps direct blood *due to more activity more blood flowing through capillaries, will need more oxygen. * lots of cellular respiration for metabolic need -temperature cold= vasoconstrict.

Arterioles

? typically have a tunica media composed of six or fewer layers of smooth muscle cells. * smallest arteries 0.3 in diameter to 10 micrometers * have 6 layers smooth muscle in tunica media * Larger ? have all 3 tunics, where as the smallest ? may have a tunica intima surrounded by a single layer of smooth muscle cells.

Starling's Law of the Capillaries

? was the first to discover that hydrostatic and osmotic forces work against one another to drive the filtration and reabsorption of materials across a capillary law. * net filtrantion pressure changes as blood moves from the arterial end o the capillary to the venous end of the capillary. * On the arterial end of a capillary, HPb is typically around 35mmHg, Hp if is assumed to be 0mmHg, COPb is around 26mmHg, and COP if is around 5mmHg. The net filtration pressure is calculated as follows: (35mmHg-0mmHg)-(26mmHg-5mmHg)= 35mmHg-21mmHg=14mmHg A positive value indicates that the hydrostatic pressure pushing fluids out of the blood is greater than the net colloid osmotic pressure pulling the fluid back to the capillary. Venous end: Blood hydrostatic pressure decreasea continuously as it moves through the capillary to reach the venule end, because there is a net movement of fluids out of the capillary as blood moves through the length of the capillary. This smaller amount of blood means the blood hydrostatic pressure at the venous end of a capillary is lower -usually around 16-20mmHg. ** Both blood colloid osmotic pressure and interstitial fluid osmotic pressure remain constant throughout the capillary and have values similar to those on the arterial end of the capillary.

capillary blood pressure

??? must be sufficient for exchange between the blood and surrounding tissue, but not so high it would damage the fragile ?

Veins

A ? thickest layer is the tunica externa , and has a larger lumen. They also have valves.

Metarteriole

A capillary bed is formed by a ? which is a branch of an arteriole. The proximal part of the ? is encircled by scattered smooth muscle cells where as the distal part of the ? (called the thoroughfare channel ) has no smooth muscle cells.

vasodilation

A decrease in o2 level in skeletal muscle would initiate an autoregulatory mechanism that would stimulate ? in the arterioles supplying the muscle.

Carotid body

A peripheral chemoreceptor tha tis located atthe bifurcation of each common carotid as it splits into an external carotid and an internal carotid artery. Sends nerve signals via the glossopharyngeal nerve.

Arterial Filtration

A process that occurs on the arterial end of a capillary, is the movement of fluid by bulk flow out of the blood through the openings in the capillaries. During this process, fluids and small, dissolved solutes flow through easily whereas large solutes are generally blocked.

End Arteries

A single splenic artery delivers oxygenated blood to the spleen with the exchange made in a capillary bed of the spleen and a single splenic vein drains deoxygenated blood from the spleen. Arteries that provide only one pathway through which the blood can reach an organ are referred ti as ? ?

cross-sectional area

A vessel is the diameter of the vessel's lumen.

capillary

A(n) ? is a type of vessel with the smallest pressure gradient that must be overcome by contraction of skeletal muscles and breathing? a) artery b) vein) c) capillary d) sinusoid

tumor angiogenesis

Abnormal cells of cancerous tumors require the delivery of oxygen and nutrients and the removal of their wastes. Thus, a critical event in development of a cancerous tumor is the formation of blood vessels within the tumor a process called ? ? . This process is initiated when cancerous cells release molecules that cause normal host cells to release growth factors that stimulate angiogenesis.

the carotid bodies detected low CO2 and high O 2 levels from exercising and stimulated the vasomotor center to vasoconstrict the vessels of the head and neck

After her workout, Arlene lies down on a mat to stretch out her leg muscles. She stands up suddenly after stretching and feels a bit light-headed. However, the light headed feeling passes quickly. What physiologic process occurred that resulted in the passing of her light headed feeling? a) The aortic bodies detected an increase in blood pressure in the head and initiated a chemoreceptor reflex that decreased blood pressure. b) The carotid bodies detected low CO2 and high O2 levels from exercising and stimulated the vasomotor center to vasoconstrict the vessels of the head and neck. c) Only alpha receptors in the head and neck initially were being stimulated, resulting in the light headed feeling. d_ The baroreceptors within the carotid detected decreased stretch in the carotid vessel wall and initiated an autonomic reflex to increase blood flow to the head and neck.

deep femoral artery

Alejandro was hit by a car, which resulted in massive injury and bleeding to his right foot. You realize that you have to compress a lower limb artery so that Alejandro will not lose too much blood. Which vessel , if compressed, will completely stop the flow of blood to the foot? a) anterior tibial artery b) posterior tibial artery c) deep femoral artery d) popliteal artery

valves

All of the following would be found in large arteries except? - don't need valves because heart pressure pumping.

blood vessels

Arteries have high pressure b/c close to heart and have large radius (ie. low resistance) Veins: also have large radius, but are far from heart and are sometimes downstream from high resistance vessels .. so have low pressure. Arterioles= landslide- below landslide = low pressure feeding into capillary beds * Cross section of capillaries - higher than arteries & veins - decreased pressure due to branching into 1000 rivulets - less pressure through small diameter - Arteries = large radius + close to heart - veins= large radius but far from heart.

It would be beneficial for movement and nutrients of those joints.

Arteries tend to have a lot of vascular anastomoses around body joints, such as the elbow and knee. Can you think of a reason this would be beneficial?

precapillary sphincter

At the origin of each true capillary , a smooth muscle ring called the ? ? controls blood flow into the true capillaries.

Factors that affect resistance

Blood viscosity-thickness Total blood vessel lengt Blood vessel diameter * resistance =(length of vessel X viscosity of blood) /radius of vessel * As viscosity increases so does resistance -dehydration, over production of RBC, more salt=dehydration * Total blood length - more length= more resistance(ie. wt. gain) - pregnancy-greater resistance - angiogenosis - muscles grow bigger cause work out * Diameter - plague, other sclerosis - vasodilation/vasoconstriction * What has the greatest effect on resistance is Radius

artery, veins

Both ? ? have a tunica intima, tunica media and tunica externa

Atherosclerosis

Characterized by the presence of an atheroma (tumor) which leads to thickening of the tunica intima and narrowing of the arterial lumen. Etiology: (cause) response to injury is the most widely accepted... injury to the endothelium of an arterial wall, especially repeated injury caused by infection, trauma, or hypertension. .. which results in inflammation reaction, eventually leading to a development of an atheroma. The injury becomes more permeable which encourages leukocytes and platelets to adhere to the lesion and initiate inflammatory response.

subclavian, axillary, brachial, radial, ulnar

Choose the correct pathway that blood flows through in the upper limb arteries. a) subclavian-->axillary-->ulnar-->radial-->brachial b) subclavian-->axillary-->brachial--> cephalic -->basilic c)subclavian-->ulnar-->brachial-->radial d) subclavian-->axillary-->brachial-->radial and ulnar

Arteries Function- pump blood awayfrom heart tunic size- tunica intima, tunica media & tunica externa lumen size- dia2.5 to 1cm BP Arterioles regulate BP systemically to all areas of body Veins Function tunic size tunica media lumen size increase in dia. as they extend from capillaries to the heart. BP 55% blood in vein walls as reservoir

Compare and contrast arteries and veins with respect to function, tunic size, lumen size and blood pressure.

Respiratory pump

Contraction of diaphragm - abdominal pressure- squeezes abdominal veins-pressure in abdominal veins - thoracic pressure - pressure in thoracic veins - so blood moves from abdominal veins - thoracic veins (ie. toward heart) * Why the core is so important the diaphragm is another pump system * Pressure gradient - Move higher to low.

Now imagine blood flowing through a blood vessel. There is a point of constriction in the blood vessel. What happens to pressure below the constriction?

Decreased

Arterial System

Elastic Arteries (conducting arteries) -largest diameter -more elastic -don't vasoconstrict -always open and dialated Muscular Arteries (distributing arteries) -deliver blood to specific body organs -thickest tunica media Arterioles -smallest vessels in arterial system - constriction/dialation alters blood flow to tissues

Action of elastic arteries

Expand during systole Recoil during diastole -results in pulsating arteries -blood keeps moving because the arteries recoil -have pressure in system even during diastole - low pressure pulse as move through arterial system.

SNS vasoconstriction Vasodilation in coronary/skeletal muscles

Explain how it is possible for the sympathetic division to cause vasoconstriction in most blood vessels but vasodilation in coronary and skeletal muscle blood vessels.

hydrostac pressure: Osmotic pressure: change from arteriole end to venule end:

Explain the difference between hydrostatic and osmotic pressures. How do these pressures change from the arteriole end of a capillary to the venule end of a capillary?

The more weight or growth the longer the blood vessels then have to stretch. This means the heart has to pump a greater blood volume for the nutrients in the blood to reach the tissues the lengthened blood vessels supply.

Explain why an overweight individual with high blood pressure is advised to lose weight. Include in your response the relationship of blood vessel length, resistance and blood pressure.

Baroreceptor reflex

HIgh BP 1) Stimulates: ^ BP, arterial BP rises above normal range 2) Baroreceptors in carotid sinuses and aortic arch are stimulated 3) ^ impulses from baroreceptors stimulate the cardioinhibitory center (and inhibit cardioacceleratory center) and inhibit vasomotor center 4a) Decrease sympathetic impulses to heart cause decrease HR decrease contractility and decreased CO. 4b) decreased rate of vasomotor impulse above vasodilation causing decreased P 5) decreased CO and decreased R return blood to homeostatic range. ***think about what you want to happen.

Heart Pump Arterial system Capillary system Venous System

Heart Pump: pump force blood Arterial= away from heart, pressure reservoir, help blood move around arterial system Capillaries= where every thing is exchanged Venous= back to heart, blood reservoir, blood stored in venous system

Beta receptors

In smooth muscle cells that contain ? ? relax in response to epinephrine, which causes vasodilation of these blood vessels. -note: the source of epinephrine hormone is the adrenal medulla, which releases both of the hormones in response to stimulation by the SNS. (Beta blockers)

Pulmonary Trunk

In the pulmonary circulation, deoxygenated blood is pumped out of the R ventricle into the ? ? This vessel bifurcates into the L & R pulmonary arteries that go to the corresponding lungs.

blood vessel Wall structure influences function

Internal diameter -Lumen diameter lg. -capillaries sm. interal dia. -companion vessels -same region -veins have larger lumen (knob in middle) Wall thickness - direct proportion to tension on vessel -tension =pressure x radius - how much pressure as well as radius * closer to heart = more pressure -Arteries are closer to the heart than veins -capillaries: low pressure, 1 cell layer thick Elasticity -elastin contractility -smooth muscle Fibrous Tissue -collagen in tunica externa -veins have more collagen, outer sheath prevent blood vessels from bursting

tunica intima, tunica media, tunica externa

List and describe the 3 tunics found in most blood vessels

Vasoactive chemicals

Local blood flow is also altered in response to tissue damage or as part of the body's defense systems. The stimulus is changing concentrations of certain chemicals collectively called ? ? . They are classified according to their action as either vasodialators or vasoconstrictors.

Cerebral Edema

Maintaining a normal MAP to the brain is critical. A possible consequence of elevated Map is ? ? which is excess interstitial fluid. The high MAP substantially increases filtration in the capillaries of the brain.

Total Blood flow

Maintaining sufficient local blood flow throughout the body (to ensure adequate perfusion of all tissue) ultimately depends upon ? ? ? . This is the amount of blood transported throughout the entire vasculature in a given period of time (usually in liters per minute). -? ? ? = cardiac output(CO). The average cardiac output at rest is 5.25 (L/min.) and may increase substantially during exercise. If CO increases, ? ? ? increases, and additional blood is available to body tissues. If CO decreases, ? ? ? decreases and less blood is available to body tissues.

Calculate MAP

Map=diastolic +1/3 pulse pressure Pulse Pressure =systolic -diastolic Systolic =140 Diastolic = 80 Calculation (140-80=60, 1/3 of 60=20, 80+20=100) Map =100

Capillary Beds (Capillary Plexus)

Microcirulation, flow of blood thru a capilly bed - thoroughfare channel (vascular shunt) - true capillaries - precapillary sphincters - open/close * 1.5 flows through capillary beds - all open @ same time BP too low & can pass out - Anaphalxis can cause @ any time 40% of capillaries are open. -short distance from arteriols - 2 diff. routes can use - through channel - vascular shunt

Starling's law formula

NFP=(HPb-HPif)-(COPb-COPif) -hydrostatic and osmotic forces work against one another to drive the filtration and reabsorption of materials across a capillary wall. (35mmHg-0mm Hg)-(26mmHg-5mmHg)=35mmHg-21mmHg=14mmHg *NP has a + value of 14mmHg at the arterial end. -a positive value indicates that the hydrostatic pressure pushing fluids out of the blood is greater than the net colloid osmotic pressure pulling the fluid back into the capillary.

Tissue Perfussion (local blood flow)

Necessary for : a) delivery of O2 & nutrients of cells b) removal of wastes from cells c) Exchange of gases in the lungs d)absorption of nutrients from the GI tract e) Urine formation >>>Blood flow to particular tissue (at particular time) is precisely matched to meet tissue's needs through a process known as autoregulation

Angiogenesis

Occurs if short-term myogenic or metabolic controls are not adequate to meet tissue nutrient requirements. 1) the number of blood vessels increases 2)Existing vessels enlarge. >>can grow more blood vessels -does not occur unless regular blood vessels stop perfusing blood to needy tissues -add more cells -coronary blood vessels partly occluded -high altitudes cause angiogenesis due to creation of new blood vessels -cancerous tumors -drugs inhibit angiogenesis

When fat is lost, the extra length in blood vessels supplying the adipose connective tissue is lost too. Decreased blood vessel length has resulted in decreased blood pressure.

Over a period of 6 months, Harold loses 40 lbs. When Harold next visits his doctor, he discovers that his blood pressure levels have fallen too low. Which of the following best explains why Harold's blood pressure has dropped? a) When fat is lost, the extra length in blood vessels supplying the adipose connective tissue is lost too. Decreased blood vessel length has resulted in decreased blood pressure. b) Most of the fat that Harold lost was around his thoracic organs, which compressed these organs. By losing the weight, he removed this compressed force. c) The resistance in the blood vessels increased due to the fat loss, resulting in decreased blood pressure. d) The fat previously constricted the blood vessels. When Harold lost the fat, the blood vessels were allowed to dilate, and thus blood pressure was reduced.

Contraction of tunica media

Peristaltic contractions of smooth muscles in venules- venules flow contraction of smooth muscles in veins helps redistribute pooled blood. * not as thick as tunica media in arteries - peristalsic contraction- alter - tubes stay in place & moves blood through veins. - Like a snake eating an egg= peristallsis ... egg moves, snake does not . -stretch triggers peristallsis.

Vasodilation in vessels supplying skeletal muscle Too much H+=too much Co2, then increase blood flow to skeletal muscles, vasodilate -local level, not systemic. -too much acid goes w/ high co2

Predict what might happen to peripheral resistance in arterioles supplying skeletal muscle when pH levels drop or become more acidic?

Eventually, the river level upstream from the landslide rises high enough and flow resumes past the landslide. The flow entering the canyon, past the landslide, and exiting the canyon equalizes at this higher river level. To maintain flow, despite high resistance (landslide), what has happened to the pressure (water level) in the system (river canyon)?

Pressure has increased

Now imagine blood flowing through a blood vessel. There is a point of constriction in the blood vessel. What happens to pressure above (upstream of ) the constriction?

Pressure increases trying to push the plug.

Which factor (length, viscosity, or radius) has the greatest impact on resistance? Explain

Radius effects the most

Angiotensin II, aldosterone, antidiuretic hormone, and atrial natriuretic peptide.

Several hormones, in addition to epinephrine and norepinephrine participate in regulating BP. These are ? These regulate BP by altering resistance, blood volume or both. Blood volume is regulated by stimulating fluid intake or altering urine output.

Alpha receptors

Smooth cells that contain ? ? contract in response to primarily norepinephrine, which causes vasoconstriction of the blood vessels.

A landslide has just blocked a river flowing through a canyon. Does flow into the canyon change immediately?

Stays the same

interstitial fluid hydrostatic pressure

The ? ? ? also has its own hydrostatic pressure, which is the force of the ? ? on the external surface of the blood vessel. * force small most tissues is small.

degree of vascularization

The ? ? ? or the extent of blood vessel distribution within a tissue, determines the potential ability of blood delivery.

anastomosis (anastomoses)

The joining together of blood vessels

Venous Return (VR)

The movement of blood from the capillaries back to the heart via the veins. *BP is not pulsatile because the blood is far removed from the pumping action of the heart. * Bp is 20 mmHg. in the venules and almost 0 mmHg by the time the blood is transported through the inferior vena cava. to the rt. atrium of the heart. * Must be facilitated by valves w/in veins and 2 pumps (skeletal and respiratory pump)

cardioinhibitory center

The parasympathetic division (PSNS) pathways extend from the ? ? to also innervate the SA and AV nodes. Nerve signals relayed along these PSNS cause release of acetylcholine from their ganglionic neurons, which both decreases the firing rate of the SA node and lengthens the delay of nerve signals at the AV node as they are relayed along the heart's conduction pathway. -decreases HR, smaller CO (do not extend to the myocardium & so do not alter the force of contraction or stroke volume.

Vasomotion

The precapillary sphincters go through cycles of contraction and relaxing at a rate of about 5-10 cycles per minute.

How come BP does not go down to 0 during diastole?

The rubber band snaps back - the elastic arteries are retracting back to the original state.

Endothelium

The simple squamous layer of cells lining the lumen of blood vessels.

Perfusion

The specific amount of blood entering capillaries per unit time per gram of tissue is called ?

Postcapillary venule

The thoroughfare channel connects to a ? ? which drains the capillary bed.

Atrial natriuretic peptide (ANP)

This is released from the atrium of the heart in response to an increase in stretch of the atrial walls due to increased blood volume and increased venous return. -stimulates vasodilation, which decreases peripheral resistance - increases urine output, which decreases blood volume. The net effect is a decrease in BP.

Cardiovascular center

This participates in the regulation of blood pressure , regulating the heart activity and is autonomic nuclei in the medulla oblongata .

atriovenous anastomosis (shunt)

This transports blood from an artery directly into a vein, bypassing the capillary bed. -present in fingers, toes, palms & ears, and they allow these areas to be bypassed if the body is becoming hyperthermic (cold). It is the bypassing of these body structures, as blood is shunted through ? ? , that makes them particular vulnerable to frostbite.

Circulatory Shock

Tissue perfusion is inadequate to meet cell requirements for o2 and nutrients 1) hypovolemic shock -loss of circulatory fluids leads to drop in BP >>>inadequate tissue perfusion hypo=low volemic= blood volume 2) Cardiogenic shock - failure of the heart to pump effectively >>>heart muscle stop pumping does not push blood through fast 3) Vascular shock -normal blood volume but extreme vasodilation of blood leads to drop in BP >>> anaphalactic shock, masive histamine release= vasoconstriction ***stress response not the same as circulatory response.

Regulation of BP

To maintain adequate perfusion of body's tissues, BP must be closely regulated to meet 3 major priorities: 1) Deliver adequate blood to brain & heart 2) Supply bloodto other organs of body 3) Control capillary pressure -To maintain appropriate tissue fluid volume & composition of interstitial fluids * Not to high pressure due to edema * Some needs to leadk out but not too much * Need tissue fluid volume balance

blood flow pressure gradient and resistance

Total blood flow is the amount of blood that moves through the cardiovascular system per unit time and is influenced by both blood pressure gradients and resistance, as previously described.

Myogenic controls of autoregulation

Vascular smooth muscle directly responds to stretch. -increased stretch>> vasoconstriction -decreased stretch >> vasodilation >keeps tissue perfusion fairly constant despite changes in systemic BP ***(this is exactly opposite of baroreceptors. The mechanism regulates blood flow while baroreceptors regulate BP) local not systemic -arterioles -stretch directly, respond with vasoconstriction -do not have flow be high..not bust out capillaries -low BP-wont porfuse the capillaries as well. -sluggish flow-vasodilate Baroreceptors : regulate systemic BP, then all blood vessels need to dialate -too low -blood vessels vasoconstrict

capillaries

Velocity of blood flow is the slowest in ? a) muscular arteries b) capillaries c) veins d) elastic arteries

1) Skeletal muscle "pump" w/ one way valves 2) Respiratory "pump" 3) contraction of tunica media

Venous adaptations for returning blood to the heart

Venous System

Venule -smaller & thinner -porous *Transport from capillaries back to heart -10% pressure-low pressure -can hold 65% total blood volume - low pressure lg. volume system act somewhat like capillaries * contraction of the heart does not force blood through the venous system Vein: -3 tunics -thinner wall, larger lumen than arteries

Hemorrhoids (piles)

Vericose veins in the anorectal region are called ? These occur due to increased intra-abdominal pressure, as when a person strains to have a bowel movement or when a woman is in labor during childbirth.

regression of vessels

What (returns to previous state) of vessels is also possible. Some skeletal muscle blood vessels ? when an individdual who was physically active becomes sedentary or blood vessels in adipose tissue ? when the amount of adipose tissue is decreased through restriction of food and increased physical activity.

Vertebral vein, external jugular vein, internal jugular vein

What 3 primary veins drain the neck and head?

stretchability of blood vessel , amount of resistance, diameter (vasoconstrict/vasodilate), compliance w/ vessel walls

What affects BP?

Elastic Arteries

What are ? ? that have vast arrays of ? fibers in their tunic media? The abundant ? fibers allow stretch to the ? to strech and accomodate the blood when a heart ventricle ejects blood into it during ventricular systole (contraction) and then recoil which helps propel the blood through the arteries during ventricular diastole (relaxation)

vericose veins

What are dialated and tortuous veins where the valves have become nonfunctional, causing blood to pool in one area and the vein to swell or bulge.

histamine and bradykinin

What are inflammatory mediators which are released in response to trauma, an allergic reaction, an infection or even exercise. These cheicals cause vasodilation by either directly stimulating arterioles or indirectly by stimulating endothelial cells of the vessel to release nitric oxide.

Vasodilators

What are substances that cause smooth muscle relaxation, which results in both vasodilation of arterioles and opening of precapillary spincters.

blood viscosity, total blood vessel length, blood vessel diameter

What are the 3 major factors that affect resistance?

arteries, arterioles, capillaries, venules, veins

What are the 5 types of blood vessels?

aorta, pulmonary trunk, brachiocephalic, common carotid, subclavian

What are the largest arteries closest to the heart and common iliac arteries are examples of elastic arteries.

Neural: via cardiovascular center, vasomotor center Hormonal: Adrenal medulla hormones, ANP, ADH, angiotensin Renal: direct renal mechanism, indirect renal mechanism.

What are the long term and short term changes that can modify BP?

heart, lungs, esophagus and diaphragm

What are the main thoracic organs?

vasomotor center

What controls the degree of vasoconstriction and vasodilation of blood vessels, is in the distinct group of autonomic nuclei in the medulla oblongata for regulation of blood pressure? * regulates the degree of vasoconstriction /vasodilation * Blood vessels do not have dual innervation, they are innervated by the sympathetic division w/ no innervation by the PSNS. - only SNS extend from the ? ? to the blood vessels/ the neurotransmitter norepinephrine is also released from these ganglionic neurons.

varied Blood Pressure

What depends on compliance of vessel walls, distance from heart and resistance? -BP force of blood against the wall

It causes blood pooling and a slowing of blood flow. Decreases venous return & BP

What effect does a long period of skeletal muscle inactivity have on blood flow?

It causes blood pooling and a slowing of blood flow. Don't move blood pools blood clots.

What effect does a long period of skeletal muscle inactivity have on blood flow?

Circulatory shock

What happens when there is insufficient blood flow for adequate perfusion of the body's tissues. This is typically due either to impaired pumping of the heart. Congestive heart failure, malfunctioning pacemaker or low venous return. -decreased blood volume due to hemorrhage, dehydration, or systemic release of histamine in an allergic reaction that increases capillary permeability. - an obstructed vein - Venous pooling caused by extended immobility or by extensive vasodilation (resulting from certain bacterial toxins or from brainstem trauma that results in loss of vasomotor tone)

Arteriole structure/function

What has a constriction (e.g. small diameter) increases upstream pressure (e.g. arteries) and decreases down stream pressure (e.g. capillaries & venous system)? What has a lanslide affect ... low pressure feeding into the capillaries?

Vein structure and function

What has a large radius, but are far from the heart and downstream from high resistance vessels so have low pressure?

Capillaries

What has high cross-sectional area, so low pressure due to branching into 1000 rivulets, low pressure through small diameter?

arterial cross section

What has high pressure b/c close to the heart and have large radius (i.e. low resistance) ?

blood vessel radius

What has the greatest effect on resistance is ?

Direct Renal Mechanism

What helps stabilize blood pressure? Independent of hormones or nervous control. -Increased blood volume or BP to the kidneys, increased filtration to urine output, increased urine output, to decrease of blood volume which in turn decreases BP and vice versa.

Circulatory portal system

What is a different type of blood vessel arrangement where blood flows through two capillary beds, with two capillary beds separated by a portal vein?

nitric oxide (NO)

What is a very powerful, shortlived vasodilator?

fenestrated capillaries

What is composed of a complete, continuous lining of endothelial cells and a complete basement membrane. Small regions of the endothelial cells are extremely thin; these thin areas are called ? (or pores) -They are small enough to prevent formed elements from passing through the wall

Chemoreceptors

What is most important in regulating respiration but are secondarily involved in regulation blood pressure. - high CO2 levels, low pH, very low oxygen levels stimulate the ? and increase their firing primarily stimulates the vasomotor ctr. -Vasomotor responds by increasing resistance and shifts blood from venous reservoirs to increase venous return. - The changes raise BP and increase blood flow, including blood flow to the lungs, which allows for an a an accompanying change in respiratory gas exchange...blood gas levels return to normal.

antidiuretic hormone (ADH)

What is released from the Posterior pituitary in response to nerve signals from the hypothalamus. -hypothalamus stimulates the posterior pituitary following either detection of increased concentration of blood or stimulation of hypothalamus by angiotensin II. -ADH increases the absorption of water in the kidney, decreasing its loss in the urine; this helps maintain blood volume and BP. -ADH also stimulates the thirst center so that there is fluid intake, and blood volume increases. (Extreme cases of low blood volume as might occur w/ hemorrhaging, extensive release of ADH occurs, which causes vasoconstriction. Vasoconstriction increases peripheral resistance and BP (also referred to as vasopressin)

Pulse Pressure (PP)

What is the additional pressure placed on the arteries from when the heart is resting to when the heart is contracting ? ? ? can be calculated by taking the difference between the systolic and diastolic pressure. Hg(120mmHg-80mmHg=40mmHg). **Pulse pressure is significant because it is a measure of the elasticity and recoil of arteries. ** Permanent changes in pulse pressure may be an indication of unhealthy arteries.

Mean Arterial Pressure (MAP)

What is the average (or mean) measure of the blood pressure forces on the arteries ? Because diastolic pressure usually lasts slightly longer than the systolic pressure , ??? is not simply an average of these two pressures so it's calculated by: MAP=Diastolic pressure + 1/3 pulse pressure **So for a person with average blood pressure : (80+40/3=93) ***MAP is significant because it provides a numeric value for how well body tissues and organs are perfused. -A map lower than 60 mmHg may indicate insufficient blood flow, and a very high MAP could indicate the delivery of too large of blood flow to body tissues w/ the possibility of causing edema (swelling) in the tissues.

Blood pressure gradient

What is the change in blood pressure from one end ofa blood vessel to its other end. A ? ? ? exists in the vasculature because blood pressure is highest in the arteries as the heart rhythmically contracts, and it is lowest in the veins. * The driving force that propels blood through the vessels.

myogenic response

What is the contraction and relaxation of smooth muscle within blood vessels in response to changes in stretch of the blood vessel wall. -An increase in systemic blood pressure causes an additional volume of blood to enter the blood vessel, which stretches the smooth muscle w/in the blood vessel wall.

Net Filtration pressure (NFP)

What is the difference between the net hydrostatic pressure and the net colloid osmotic pressure (difference between the blood and the interstitial fluid hydrostatic pressures). *NFP=(HPb-HPif)-(COPb-COPif) The net filtration pressure may be determined by the following equation: where HPb= the hydrostatic pressure of blood, HPif = the hydrostatic pressure of the interstitial fluid, COPb = the colloid osmotic pressure of blood, and COP if = the colloid osmotic pressure of the interstitial fluid.

blood pressure (BP)

What is the force per unit area that blood exerts against the inside wall of a vessel?

Blood colloid osmotic pressure (BCOP)(oncotic pressure)

What is the force that draws fluid back into the blood due to the proteins in the blood, such as albumin?

Angiogenesis (angio-vessel/genesis-production)

What is the formation of new blood vessels in tissues that require them. This process helps provide adequate perfusion through long-term anatomic changes that occur over several weeks to months.

Continuous capillaries

What is the most common type of capillary? The endothelial cells form a ? ? lining around the lumen that rests on a complete basement membrane. -found in muscle, skin, the thymus , CNS & lungs

Reabsorption

What is the movement of fluid by bulk flow in the opposite direction, back into the blood??

Arteries-->Arterioles-->capillaries-->venules-->veins-->heart

What is the pathway of blood from heart through the vessels?

Hydrostatic pressure (HP)

What is the physical force exerted by a fluid on a structure? * blood hydrostatic pressure -Is the force exerted per unit area by the blood as it presses against the internal surface of the vessel wall? -Blood ? ? promotes filtration from the capillary

Autoregulation

What is the process by which a tissue itself regulates or controls its local blood flow in response to its changing metabolic needs. The initial stimulus for ? typically inadequate perfusion due to increased metabolic activity of tissue. * ? is most noticeable when blood suply is temporarily disrupted and then restored. When the blood flow is temporarily disrupted, the tissue is deprived of needed oxygen and nutrients, and metabolic wastes accumulate.

Blood flow velocity

What is the rate of blood transported per unit time and typically measured in centimeters per second?

renin

What is the substance produced in a the kidney and releases the enzyme ? into the blood in response to either low bP or stimulation by the SNS

peripheral resistance (PR)

What is typically used when discussing the resistance of blood in the blood vessels ? (as opposed to resistance of blood in the heart) Factors affecting resistance: -blood visCosity - vessel length - size of lumen of blood vessels.

Cardiac output (CO) CO=SV x HR -Short term, how would you change SV, how strong or weak? Peripheral resistance: PR = length of vessel x viscosity /radius^4 -length, viscosity & radius Blood volume -increase BV=increased BP * Hypovolemic shock -->need IV fluids to increase bodily fluids -drink H2O BP will go up, gidneys get rid of H2O and help stabilize High BP.

What mechanisms act to stabilize BP and focus on manipulating 3 major variables? What is the formula?

aortic body

What peripheral chemoreceptors are located in the arch of the aorta, sends sensory input to the cardiovascular ctr; they send nerve signals via the vagus nerve.

Blood Viscosity

What refers to the resistance of a fluid to its flow. More generally it is the thickness of a fluid. The thicker the fluid the more viscous it is, and the greater resistance to flow. -4.5 to 5.5 more viscous than water - change in blood's viscosity causes change in resistance of flow through a vessel. - dehydration can cause viscosity

Renin-angiotensin system

What straddles short-term neural regulation and long-term hormonal regulation because the synthesis of the ? ? is initiated by the nervous system and ? ? causes the release of other hormones.

Metabolic controls of autoregulation

When blood flow is too low to meet tissues needs, O2 & nutrient levels decrease and metabolic byproducts increase -these factors stimulate vasodilation and relaxation of precapillary sphincters (decrease o2, increased co2, H+, K+, adenosine, prostagladins and nitric oxide) Blood flow too stimulates vasodilation and relaxation -more blood reaches needy tissues

Atrial Natriuetic peptide (stretch of arteriole walls)

When blood volume is increased, which of the following hormones would you expect to increase?

Aneurysm

When part of the arterial wall thins and balloons out. This wall is more prone to rupture, which can cause massive bleeding and may lead to death. ? most commonly occur in the arteries at the base of the brain or aorta.

chemoreceptor reflexes

When stimulated, they initiate ? ? which are negative feedback loops that ultimately bring blood chemistry levels back to normal.

reactive hyperemia

When the blood flow is restored, there is a marked increase in blood flow to the affected tissue- a condition called ? ? . The additional blood is required to resupply the oxygen and nutrients and eliminate the accumulated wastes. * Example: enter a warm room after being outside in the cold, and your cheeks turn bright red. When outside, blood vessels constrict, when come in ... return to normal ... blood flow to skin resumes.

decreased carbon dioxide, decreased pH (increased H+) and low O2

Which of the following decreases perfusion of a tissue? a) decreased total blood flow b) vasodialator c) angiogenesis d) increased carbon dioxide, decreased pH (increased H+) and low O2

Total blood flow is significant in maintaining adequate perfusion of all tissues

Which of the following is accurate? a) Total blood flow increases with a steeper gradient (assuming cardiac output stays the same) b) Total blood flow decreases with increased resistance (assuming cardiac output stays the same) c) Total blood flow is significant in maintaining adequate perfusion of all tissues. d) All are correct

fenestrated capillaries allow for larger amounts of materials to be exchanged is incorrect. **Fenestrated capillaries are extremely thin; these thin areas are called fenestrations (or pores)... they are small enough to prevent formed elements from passing through the wall but large enough to allow the movement of smaller plasma proteins.

Which of the following is not a characteristic of a capillary? a) fenestrated capillaries allow for larger amounts of materials to be exchanged. b) Sinusoid capilaries are the main type of capillary around the brain. c) capillaries are often arranged in a capillary bed that is supplied by an arteriole d) The capillary wall consists of an endothelium and a basement membrane only- there is no subendothelial layer.

The largest tunic in a vein is the tunic externa

Which statement is accurate about veins? a) veins always transport deoxygenated blood. b) veins drain into smaller vessels called venules c) The largest tunic in a vein is the tunica externa d) The lumen of the vein tends to be smaller than that of a comparably sized artery

The cross-sectional area of the capillary beds is approximately 2000 x that of the aorta

Why does blood velocity decrease as it flows into a capillary bed?

The muscular arterioles do not exhibit elastic rebound

Why has pulse pressure disappeared by the time blood reaches capillary beds?

These are the smallest blood vessels in our body

capillaries

deep vein thrombosis (DVT)

refers to a thrombus (blood clot) in a vein. The most common site for the thrombus is a vein in the sural region (calf) . DVT typically occurs in individuals w/ heart disease or those who are inactive or immobile for a long time.

sympathetic motor tone

results in vasoconstriction, which allows for varying degrees of change from this slightly contracted state. Blood vessels can either be vasoconstricted to a greater degree to decrease blood blow or vasodilated to allow more blood into an area.

venous net filtration pressure

(16mmHg00mmHg)-(26mmHg-5mmHg)=NFP 16mmHg -21mmHg =-5mmHg ** A negative value for NP occurs because blood hydrostatic pressure is less than the net osmotic pressure. Consequently, reabsorption occurs on the venous end of the capillary with a net movement of fluid back into the blood vessel from the surrounding tissue. ** specific values depend upon the part of the body, the amount of blood entering a specific capillary bed and the general health of the individual.

Ohm's Law for Resistance

Blood flow = difference in pressure between 2 points on blood vessel divided by resistance F= blood flow Delta P = difference in pressure between two points o a blood vessel R= Resistance

Ohm's law equation

Blood flow =difference in pressure between 2 points on blood vessel divided by resistance. -Blood flow is proportional to the difference in pressure. -Physical relationships will influence flow through out the body.

A landslide has just blocked a river flowing through a canyon. What begins to happen to the river level upstream from the landslide?

Decreased until the blockage is removed or circumvented.

Vessel Radius: Vessel Length: blood viscosity: BP flow:

Describe the relationship of vessel radius, vessel length, blood viscosity and blood pressure to flow.

Vasoconstrictors

Blood flow increases into a capillary bed. ? are substances that cause smooth muscle contraction, which results in both arterioles vasoconstricting and precapillary sphincters closing. Thus, blood flow decreases into a capillary bed.

hepatic portal vein

Blood from the splenic vein, the inferior mesenteric vein and the superior mesenteric vein into the ? ? ? , which drains blood to the liver (at the inferior portion.) It then flows through the sinusoids of the liver. The venous blood mixes w/ arterial oxygenated blood entering the liver via the hepatic arteries. They merge and flow w/in the liver sinusoids. Blood leaves the liver through the hepatic veins that merge w/ the inferior vena cava.

all of the above

Blood pressure is regulated by the ? a) cardiac center b) vasomotor center c) hormones d) All of these are correct

hepatic portal system

Blood that has passed through the capillaries of digestive organs and the spleen , and is then drained by its respective veins is not directly returned to the inferior vena cava and returned to the heart. Instead the blood is transported from the veins of the digestive organs and spleen into a ? ? ? that drains the blood into the liver before this blood drains to the inferior vena cava.

Capillary bed

Capillaries do not function independently ; rather a group of capillaries function together and form a ? ?

Why do capillaries have high resistance but low pressure?

Capillaries have high cross-sectional area , so low pressure.

Blood vessel diameter

- plaque, atherosclerosis -vasodilation/vasoconstriction

Blood pressure (BP)

- pressure = force applied over an area - Force of blood on vessel wall (mmHg) * force applied over an area * How much pressure the blood is putting on the walls of the vessels. * systemic arterial pressure in large vessel near the heart.

norepinephrine and epinephrine

-Released by adrenal medulla in response to stess -nicotine -Both hormones enhance SNS Response -increase CO -Generalized vasoconstriction ***Beta blockers block effects of these hormones and decrease BP

blood pressure (BP)

-pressure = force applied over an area -force of blood on vessel wall (mmHg) -how much pressure the blood is putting on vessel walls.

Pathology of BP regulation : Hypotension

1) May prolong life & prevent CV disease 2) can lead to inadequate o2 delivery -acute hypotension: allergic response -orthostatic hypotension: blood pools in extremeties -chronic hypotension: addisons disease, malnutrition >>>hypotension = BP less than 90/60

Baroreceptors

1) Stretch receptors located in walls of : -carotid arteries -aortic arch - Most large arteries in neck & thorax If high BP-stimulates the Baroreceptors -will fire less often 2) Stimuli from baroreceptors sent to CV Center, which modifies response to stabilize BP

Increased peripheral resistance larger circulating blood volume Redistribution of blood flow

Activation of the SNS division & subsequent stimulation of the adrenal medulla causes the following?

Now imagine blood flowing through a blood vessel. There is a point of constriction in the blood vessel. What happens to flow below (downstream of) the constriction?

Flow greatly decreases

A landslide has just blocked a river flowing through a canyon. With this increased resistance, what happens to flow past this resistance?

Flow slow or decrease

d) colloid osmotic pressure in the capillary decreases and fluid remains in the interstitial fluid, potentially causing edema.

If a patient has cirrhosis of the liver and is unable to produce sufficient albumin and other plasma proteins, then what variable is changed in capillary exchanged, and what is the effect? a) There is no change in the capillary exchange process. b) Hydrostatic pressure in the blood decreases, and fluid remains in the blood. c) Colloid osmotic pressure in the capillary increases, and blood volume increases in the blood vessels. d) Colloid osmotic pressure in the capillary decreases and fluid remains in the interstitial fluid, potentially causing edema.

A landslide has just blocked a river flowing through a canyon. Flow + pressure gradient / resistance

It does affect the flow out of the canyon by slowing it down and increase the resistance

Angiotensin II

Low Blood flow to kidneys (due to low BP or low blood volume) -renin released Renin acts as an enzyme to produce angiotensin II Angiotensin II increase BP to : -intense vasoconstriction -Release aldosterone & ADH to increase blood volume. ** increase reabsorbption of H2O therefore raise BP

If you injected erythropoietin, what would happen to resistance? Why?

More RBC, more viscosity= more resistance

Valves

Most veins contain numerous ?, so as to prevent blood from pooling in the limbs. The ? are formed primarily of tunica intima and strengthened by elastic and collagen fibers. ? have a anatomic structure similar to similunar ? of the heart.

Tunica Media

Of the following blood vessel components, which is the most critical in regulating diameter of blood vessels?

Systemic veins and venules

Of the following cardiovascular components, which contains the majority of the body's blood volume at any one time?

capillaries

Of the following vessel types, which are responsible for the exchange of gases and nutrient with tissues?

Veins

Of the following vessel types, which conduct blood toward the heart, regardless of oxygen content?

Prostaglandins and thromboxanes

Other vasoactive substances are local hormones released with tissue injury that can cause vasoconstriction. These help prevent blood loss from the damaged vessel.

peripheral resistance decreases

Predict the change in peripheral resistance as blood vessel diameter increases.

Now imagine blood flowing through a blood vessel. There is a point of constriction in the blood vessel. If the system stabalizes despite this constriction, what must happen to blood pressure?

Remains high trying to push the plug through greatly increasing ^P

Vessel Resistance to flow equation

Resistance = (Length x Viscosity) / Radius^4

lymphatic system

The ? ? is responsible for picking up the excess fluid and returning it to the blood. ? vessels reabsorb this excess fluid, filter it, and return it to the venous circulation.

capillaries

The ? have only a tunica intima (basement membrane and endotheilium) but do not have a subendothelial layer.

Autoregulation

The adjustment of blood flow to each tissue in proportion to its requirements at any point in time >>> adjust blood flow metabolically or myogenically

Blood Reservoirs

The large amount of blood within veins allows veins to function as ? ?. Blood may be shifted from venous reservoirs into circulation through vasoconstriction of veins.

Angiotensinogen

The liver produces a plasma protein called ? (an inactive hormone) and continuously releases it into the blood.

diastolic pressure (DP)

The lowest pressure is during ventricular diastole when the artery recoils no further; this value is recorded as ? ?

Blood Vessel Radius

The major way resistance may bemay be regulated is by altering vessel lumen radius ( and thus changing the vessel diameter). -Blood tends to flow fastest in the center of the vessel lumen, whereas blood near the sides of the vessels slows, whereas blood near the sides of the vessels slows, because it encounters resistance from the nearby vessel wall.

Venules

What are the smallest veins , measuring from 8-100micrometers in diameter? * companion vessels w/ arterioles * drain capillaries * merge from larger venules * have all 3 tunics *A venule becomes a vein when its diameter is greater than 100 micrometers.

Neural, Hormonal, renal

What are the variables influencing BP that can modify blood pressure?

true capillaries (exchange vessels)

What branches from the metarteriole and make up the bulk of the capillary bed?

Blood viscosity

as viscosity increases so does resistance -dehydration -over production of RBC -more salt = dehydration

Blood Flow

flow = volume flow rate, per time - volume of blood flowing thru blood vessel ( or organ or entire circ) in given period ( ml/min) velocity = distance per time

Blood flow

flow = volume flow rate; volume per time volume of blood flowing thru blood vessel (or entire circ) is given period velocity=distance per time ***If not specified, assume mean systemic arterial pressure in a vessel of heart

Muscular arteries

have a tunica media with numerous layers of smoothe ? flanked by elastic laminae.

Of the following blood vessel components, which is the most critical in regulating diameter of blood vessels?

tunica media

Venous anastomosis

two or more veins draining the same body region. Veins tend to form many more anastomoses than do arteries.

All of the following woud be found in large arteries accept?

valves

Of the following vessel types, which conduct blood toward the heart, regardles of oxygen content

veins

If you gained 30lbs, what would happen to resistance? Why?

vessel length extended - resistance goes up

Systemic BP-capillaries

-Blood pressure in capillaries is low --35-17mmHg -Why is it necessary & important that capillary blood pressure be low? -Nutrient exchange, can't get reabsorption -Need low because the capillaries are super thin -High Pressure causes adema (too much fluid being forced out)

Metabolism

-Cellular respiration is a metabolic process -main way that chemical energy is harvested from food and converted to ATP -Most CO2 binds w/ water resulting in release of H+, Co2 H2Co3, H + HcO3 -If there isn't enough o2 available for aerobic respiration , then can make QTP via anaerobic metabolism -lactic acid is released as byproduct. *** gets signal out calling for more blood flow to the needy tissue & increase perfusion.

Fluid loss from hemorrhage, excessive sweating

-decreased blood volume -decreased blood pressure -Baroreceptors -Activation of vasomotor and cardioacceleratory centers of the brain stem -Increased heart rate -cardiac output decreased -low mean arterial Pressure (MAP)

pulmonary circulation

1) blood leaves the R ventricle w/ a systolic pressure of 15 to 25mmHg, depending upon whether the body is resting or active. 2) Blood pressure drops as the blood passes through the pulmonary trunik and R & L pulmonary arteries =pressure 10mmHg in the pulmonary capillaries of the aveoli. The lower pressure means that the blood moves more slowly in pulmonary capillaries than in systemic capillaries, facilitating gas exchange w/ in th lungs 3) Blood exits the pulmonary capillaries into progressively larger veins that become the pulmonary veins; BP is almost 0 mmHg as these veins empty into the L atrium.

Arterial Pressure fluctuation

1) can feel this pressure fluctuation as pulse in artery -pulse pressure=systolic pressure-diastolic pressure 2) Because pressure fluctuations, Mean arterial pressure (MAP) is used to calculate pressure that propels blood to tissued: MAP=Diastolic Pressure + 1/3 (Pulse Pressure) * diastole lasts longer so can't use midpoint between systolic and diastolic * BP force of pressure against walls of arteries -distance, elasticity, resistance, Radius, length *Pressure will fluctuate w/ heart beat. * No go down to 0 during diastole because the arteries elastin are snapping back.

Extrinsic mechanisms influencing blood vessel diameter

1) neuronal & hormonal factors -all wk together to adjust BP -autoregulation neuronal -hormonal -baroreceptors These mechanisms focus on regulating BP

blood vessel length

? ? ? -more length = more resistance (ie. wt. gain) -pregnancy -angiogenesis -muscles grow bigger due work out

a) epinephrine

Arlene heads to the gym and initiates a vigorous exercise regimen. Which hormone will not be released? a) epinephrine b) atrial natriuretic peptide c) angiotensin II d) norepinephrine

artery

An ? has a thicker tunica median and a smaller lumen.

vessel diameter

An increase in ? will result in an increase in blood flow to an area. a) vessel length b) vessel diameter c) blood viscosity d) the number of formed elements

Angiotensin II

Angiotensin I is then converted to? by angiotensin-converting enzyme, an enzyme associated w/ the capillary endothelium, so most (but not all) angiotensin I conversion to ? ? occurs in the lungs.

Autonomic Reflexes

BP Decrease: -decreased stretch when rise from bed is detected by baroreceptors in aortic arch -baroreceptors decrease frequency of nerve signals w/in vegus & glossopharyngeal nerves to both the cardiac ctr. & vasomotor ctr. - cardio-acceleratory ctr. w/in the cardiac ctr. increasesnerve signals along SNS extending to the heart, SA & AV nodes.. HR & SV increase resulting into increased CO. - Vasomotor Ctr increases nerve signals along the SNS pathways that extend to blood vessels.... shifting blood from venous reservoirs. BP Increase: - Increased stretch: detected by baroreceptors in the aortic arch, carotid sinuses or both - baroreceptors increase frequency of nerve signals relayed along sensory neurons w/in the (CN X; CN IX) to both the cardiac and vasomotor ctr. of the medulla oblongata. - decreases nerve signals relayed along the SNS extending to the heart including SA& AV odes... - decreases nerve signals along SNS to blood vessels resulting in net vasodilation & decreased resistance.

stretch in arterial walls

Baroreceptors detect changes in?

arterial anastomosis

Includes two or more arteries converting to supply the same body region.

If you had a artherosclerotic plaque that decreased the effective radius of a coronary artery from 4mm to 2 mm, what would happen to resistance? Why?

Increased because like landslide, pressure goes up.

A landslide has just blocked a river flowing through a canyon. With this increased resistance, what happens to the pressure gradient?

Increased pressure gradient- pump is working harder.

vessel length

Increasing ? ? increases resistance because longer vessels result in greater friction, which the fluid experiences as it is transported trough the vessel. In contrast, shorter vessels offer less resistance than longer vessels w/ comparable diameters. -gained weight: more miles of additional vessel length (angiogenesis)= increased vessel resistance - wt. lossed = decreased resistance as vessels no longer needed.

interstitial fluid colloid osmotic Pressure (COPif)

Its value is relatively slow in the ? ? ? . It may range from 0 to 5mmHg. By knowing the specific valuesfor the hydrostatic and osmotic pressures, the direction of bulk flow can be determined through the calculations of net pressure.

Why should I care about any of this?

Physical relationships will influence flow throughout the body.

cardioacceleratory center (CAC)

Sympathetic division pathways extend from the ? ? to both the SA node and the AV node. Nerve signals relayed along these ANS pathways cause release of norepinephrine from their ganglionic neurons which -Increase the firing rate of the SA Node -Shortens the delay of the nerve signals at the Av node as they are relayed along the heart's conduction pathway. ***SNS pathwy increases the heart rate, cause more forceful contraction of the heart, increases stroke volume which produces greater cardiac output.

Baroreceptors

The aortic arch ? transmit nerve signals to the cardiovascular center through the vagus nerve (CN x). -Regulate systemic BP -carotid sinus ? are located w/in each internal carotid artery, ner the artery's interstitial bifurcation (branching) from the common carotid artery. - transmit nerve signals to Cardiovascular ctr. through CNIX. These ? w/in carotid sinuses monitor BP changes in the head and neck-thus, they are important in monitoring BP affecting the brain. - continually transmit nerve signals along sensory neurons w/in the vagus nerves & glossalpharangeal nerves to the cardiovascular center at a particular rate.

Vasomotor tone

The contracted state regulated by the vasomotor center in the brainstem.

How is it possible to have filtration on the arterial end, and reabsorption on the venous end, of a capillary?

The direction of movement is dependent upon the net pressure of two opposing forces at the capillary level-hydrostatic pressure and colloid osmotic pressure; both are measured in (mmHg)

systolic pressure (SP)

The highest blood pressure generated in arteries during ventricular systole when the artery is maximally stretched; this value is recorded as ? ?

tunica media

The middle and thickest layer of tissue of a blood vessel wall, composed of elastic tissue and smooth muscle cells that allow the vessel to expand or contract in response to changes in blood pressure and tissue demand.

colloid osmotic pressure (COP)

The other main force regulating filtration and reabsorption is osmotic pressure, which refers to the "pull" of water into an area by osmosis due to the higher relative concentration of solutes. ? ? ? referss to the pull of water back into a tissue by the tissue's concentration of proteins (colloid).

Capillaries

These are the smallest blood vessels in our body.

Sinusoids (discontinuous capillaries)

These have an incomplete lining of the endothelial cells with large openings, or gaps and the basement membrane is either discontinuous or absent. These opeinings allow for transport of large substances (formed elements into the blood, liver and spleen. They allow for the removal of RBC from the cardiovascular circulation, and some endocrine glands. For the movement of hormone molecules into the blood. Common feature of structure: reddish color.

skeletal muscle pump

This assists the movement of blood primarily within limbs. As skeletal muscles contract, veins are squeezed to help propel the blood toward the heart, and valves prevent blood backflow. More action more pumping.

Respiratory pump (venous return)

This assists the movement of blood within the thoracic cavity. The diaphragm contracts and flattens as we inspire (inhale). Intra-abdominal pressure increases and places pressure on the vessels within the abdominal cavity. When expire ( exhale), the diaphragm relaxes and returns to its dome shape.

intercellular clefts

Tight junctions secure endothelial cells to one another, however, they do not form a complete seal. The gaps between the endothelial cells are called ? ? Materials can move into or out of the blood either through or between endothelial cells through intercellular clefts by diffusion and bulk flow. ** The size of intercellular clefts prevents the movement of large substances including formed elements and plasma proteins, while allowing the movement of fluid containing small substances (smaller than 5nm) such as glucose, amino acids, and ions.

externa

Vaso Vasorum are found in the tunica ? of a large blood vessel. a) Intima b)media c) externa d) All these are correct

Diffusion

Within systemic capillaries, substances such as oxygen, hormones and nutrients move by ? from their relatively high concentration in the blood into the interstitial fluid and then into the tissue cells, where the concentration of these materials is lower. *Carbondioxide and waste products ? from the higher concentration in the tissue cells to the lower concentration in the interstitial fluid and then to the blood. * very small solutes (o2, CO2, glucose, ions) and fluids may ? via the endothelial cells or intercellular clefts, whereas larger solutes, such as proteins, must pass through the fenestrations in fenestrated capillaries or gaps in sinusoids.

angiotensin I

Within the blood, renin converts angiotensinogen into ?

Atherosclerosis/ high blood pressure: Atherosclerosis is a disease of the elastic muscular arteries characterized by the presence of an antheroma (tumor) which leads to thickening of the tunica intima and narrowing of the arterial lumen. This causes more friction or resistance which acts like

Your patient is Thomas, a 50 yr. old man who rarely exercises, is overweight, and only occasionally eats healthy meals, which put him at risk for atherosclerosis. Explain to him the relationship between atherosclerosis and high blood pressure.

companion vessels

arteries and veins that supply the same body region and tend to lie next to one another

Of the following vessel types, which are responsible for exchange of gases and nutrients w/ tissues?

capillaries

Total cross-sectional area

is estimated as the aggregate lumen diameter across the total number of a given type of vessel if they were all positioned side by side. * The greater the total ???, the slower the flow. Notice that capillaries have the greatest cross-sectional area and the slowest blood flow- conditions that facilitate the exchange of substances between the blood and tissues.

Aldosterone

is released from the adrenal cortex in response to several stimuli, including angiotension II. ? increases the absorption of Na+ ion and H2O in the kidney, decreasing their loss in the urine; this helps maintain BV & BP.

tunica externa

outer layer of a blood vessel which connects it to surrounding tissues, composed of collagen, vasa vasorum (vessels of vessels) can't get enough nutrients to thick wall of some vessels, so need vaso vasorum to nourish tissue in the wall of lg. blood vessels.

Of the following cardiovascular components, which contains the majority of the body's blood volume at any one time?

systemic veins and venules

tunica intima

the innermost layer of a blood vessel, composed of a single layer of squamous epithelial cells over a sheet of connective tissue; its smooth, frictionless surface allows blood to flow smoothly through the vessel