What Carries Blood Under High Pressure from the Heart to Tissue?


What Carries Blood Under High Pressure from the Heart to Tissue?

Chapter 21

  1. What carries blood under high pressure from the heart to tissue?


  1. ______is the forces involved in circulating blood.


  1. Arteries hold what type of volume?

Stressed volume

  1. ______are the last small branches off arterial tree.


  1. Where is the site of highest resistance to blood flow?


  1. Metarterioles emerge from _____ and supply a small group (10-100) of ______which contribute to a capillary bed.

Arterioles; capillaries

  1. What is the name of the vessel that is thin enough to allow exchange of nutrients; blood; fluid; etc?


  1. What structure collects blood from capillary and merges with veins?


  1. Veins bring blood _____ the heart.

Back to

  1. Veins are a major what of blood?


  1. What are the names of vessels of vessels that line the walls of large vessels?

Vasa vasorum

  1. Name the 3 structures of arteries and veins.

Tunica intima- endothelium basement membrane

Tunica media- smooth muscle (external) elastic fibers

Tunica externa ( adventitia)- merges with connective tissue surrounding blood vessel

  1. What is the largest layer in the artery?

Tunica media

  1. What type of artery is the aorta?

Elastic (conducting artery)- has smaller amount of smooth muscle and greater amount

of elastic tissue

  1. What vessels play a key role in regulating blood flow by regulating resistance?


  1. The vascular smooth muscle is innervated by what part of the autonomic system?


  1. True/False. A small change in the diameter of your arteries due to plaque build up or loss of elasticity has a small or little effect on the flow.

False – it has a huge impact; causes 90% blockage

  1. What term means intermittent contraction and relaxation of sphincter that allow filling of capillary beds?


  1. What is the function of capillaries?

Exchange of nutrients and waste between blood and tissue fluid

  1. What is the structure of a capillary?

Single layer of simple squamous epithelium and its basement membrane

  1. Name the 3 types of capillaries and describe.

Continuous – no fenestrae; pores

Fenestrated – have pores

Sinusoidal- large diameter with large fenestrae; pores

  1. Which types of capillaries have the fastest diffusion? Slowest diffusion?

Sinusoids; continuous

  1. True/False. Veins have valves.


  1. Veins hold what type of “volume”?


  1. Tell the differences between arteries and veins.

Arteries- thicker walls; circular; under pressure; no valves; more elastic; carries blood from hear.

Veins. - thinner walls; less muscle; irregular shape; not under pressure; has valves; c carries blood to the heart.

  1. If the aorta becomes stiff due to ware and tear what effect will the stiffness have on blood flow?

The blood will flow more in spurts and not in a constant cyclic manner.

  1. What causes varicose veins?

Leaky venous valves

  1. What controls blood flow to each tissue?

The tissue need

  1. What controls the cardiac output?

Mainly by the sum of all local tissue flow

  1. True/False. Arterial pressure is controlled independently of either local blood flow or cardiac output.


  1. What percentage of blood volume at rest is in the systemic veins and venules?


  1. What ways do capillaries move materials in and out?

Diffusion; transcytosis; filtration; reabsorption

  1. If filtration exceeds reabsorption where is material moving?

Out of capillary

  1. If reabsorption exceeds filtration where is material moving?

Into the capillary

  1. What do you want the rate of filtration to rate of reabsorption to be in the capillaries?

Equal to each other

  1. What is promoted by hydrostatic pressure and interstitial flow osmotic pressure?


  1. What is promoted by blodd collid osmotic pressure and interstitial fluid hydrostatic pressure?


  1. What is Starling’s law of capillaries?

The volume of fluid and solutes reabsorbed is almost as large as the volume filtered

  1. Do you have net reabsorption or filtration on the arterial sid of the capillaries?


  1. Do you have net reabsorption or filtration on the venous side of the capillaries?


  1. Where does the excess fluid go that is not reabsorbed on the venous side of the capillaries?

Lymphatic capillaries collect it

  1. High blood pressure promotes what?


  1. Low blood pressure promotes what?


  1. Blood collid osmotic pressure (BCOP) should be higher of lower on the venous side of the capillaries?


  1. If I drink pure water I will promote filtration or reabsorption?


  1. If I eat salty foods I would promote filtration or reabsorption?


  1. If BHP= 30mmHg IFOP=2mmHg IFHP = 3mmHg and BCOP = 26mmHg on arterial side of capillaries what is the net filtration?

NFP= (30 +2) – (26 + 3) = 3mmHg

  1. Pressure exerted by blood on walls of a vessel is caused by ______.

Contraction of the ventricles

  1. Pressure exerted by blood on wall of a vessel is highest where?

In aorta

  1. Greatest drop in pressure occurs where?

In arterioles

  1. Pulse pressure is difference between what?

Systolic and diastolic

  1. If a patient has a normal BP (120/80) what is their pulse pressure?

40 (120 -80=40)

  1. What is mean arterial blood pressure (MABP)?

Average pressure in arteries (not an arithmetic average)

  1. What is the equation for MABP?

MABP=diastolic BP +1/3(systolic BP – diastolic BP)

  1. Why is it 1/3(systolic BP – diastolic BP) in the MABP equation?

Because it is not an arithmetic average

  1. Blood pressure is measured by listening for what?

Korotkoff sounds – produced by turbulent flow in arteries as pressure released from

BP cuff.

  1. What are the two “pumps” are in the venous return?

Skeletal muscle and respiratory

  1. Where do you take blood pressure at?

At level of heart at brachial artery

  1. What is the first sound you hear when you take blood pressure? (systolic or diastolic)


  1. What is the second sound you herar when you take blood pressure? (systolic or diastolic)


  1. What factors affect circulation?

Pressure differences that drive the blood flow; resistance to flow; and venous return

  1. What is the velocity of blood flow equation?


  1. Where is the greatest cross-sectional area?

In capillaries

  1. As diameter of vessels decreases the total cross-sectional area ______and velocity of blood flow ____.

Increases; decreases

  1. Speed of blood flow in cm/sec is _____ related to cross-sectional area.


  1. Blood flow is slower in arterial or venous branches?


  1. Blood flow becomes faster when vessels merge to form ______.


  1. Circulation time is what?

Time it takes a drop of blood to travel from the right atrium back to the right atrium.

  1. As vessel diameter increases the velocity of fluid flow through the vessel _____.


  1. Magnitude of Q in Q=∆P/R equation is _____ proportional to ∆P.


  1. Magnitude of Q in Q=∆P/R equation is _____ proportional to R (resistance).


  1. What are the 2 resistance arrangements?

In series and in parallel

  1. If you add resistance in parallel a(n) _____ happens to resistance. In series?

Decrease; increase in resistance

  1. What are the advantages of having vessels in parallel?

Total resistance is less than any of the individual resistance; no loss of pressure; if another resistance total decreases; if increase resistance total increases.

  1. What does Poiseulle’s law state?

The flow of (Newtonian) fluid through rigid tubes is governed by pressure gradient and resistance to flow.

  1. What are the 3 properties that affect fluid and tube resistance in Poiseuille’s law?

Length of tube (l); radius of tube (r); viscosity of fluid (ŋ)

  1. What is the Poiseuille’s law equation?

R=8 ŋl/()

  1. Does a smaller vessel offer more/ less resistance to blood flow.


  1. An increase in viscosity _____ resistance.


  1. The longer the vessel the ______the resistance to flow.


  1. Resistance is regulated by what?

The radius of the vessel

  1. Very small changes in the radius will have ______affects on the resistance.


  1. Name some cases where blood viscosity can change?

Dehydration; change in hematocrit; and changes in plasma protein concentration.

  1. The greater the _____ the slower the flow.


  1. The greater the _____ the greater the flow.


  1. Obesity would lead to hypo/hypertension.


  1. What are laminar and turbulent flow?

Laminar- streamlined; outermost layer moving slowest and center moving faster.

Turbulent- interrupted; rate of flow exceeds critical velocity; fluid passes a constricton sharp turn rough surfaces.

  1. In normal conditions turbulent flow is found only where?

In aorta

  1. What is critical velocity?

Laminar flow velocity increases with increase in pressure but up to a point

  1. What type of flow is observed above critical velocity?


  1. Reynolds number is used to predict what?

Whether blood flow will be laminar or turbulent

  1. The viscosity of blood decreases with _____ in flow rate.


  1. RBC tend to collect in center of lumen thus _____ the effective viscosity.


  1. Axial streaming reduces blood viscosity at ____ thus ____ resistance.

Edge; decreasing

  1. What effect does decreased resistance have on flow?

It increases it

  1. A high hematocrit as in plycytemia increases blood viscosity which _____ blood flow through capillaries.


  1. What is shear thinning?

The apparent viscosity diminishes as the blood flow rate increases (and vice versa)

  1. The higher the compliance of a vessel the _____ volume it can hold at a given pressure.


  1. Aging decreases/ increases compliance of vessels.


  1. What do changes in compliance cause?

Redistribution of blood between arteries and veins

  1. What is the equation for compliance?


  1. What type of pump has steady pressure steady flow and no need for compliance?

Constant flow pump

  1. What has the highest compliance? Middle? Lowest?

Veins; arteries; aging arteries

  1. Cyclical pump and non-compliance vessels have what type of pressure and flow?


  1. Cyclical pump and compliant vessels have what type of pressure and flow?


  1. Laplace’s law states what?

It relates pressure; radius of vessel and tension on vessel wall

  1. The importance of Laplace’s law is in what vessels?

Capillaries and alveoli

  1. What is the term that means input during physical activity?


  1. This term means changes in pressure within blood vessel?


  1. What receptors monitor concentration of chemicals in the blood?


  1. What type of fibers does the vagus nerve have and what effect does it have on the

heart? Parasympathetic; decreases heart rate

  1. Name the 2 type of baroreflexes of blood pressure.

Carotid sinus reflex and aorta reflex

  1. What cranial nerve is involved in the carotid sinus reflex? the aorta reflex?

Glossopharyngeal (CN IX) vagus (CN X)

  1. What is orthostatic hypotension?

Decrease in BP upon standing. Blood is pulled down to the lower extremities.

  1. Locally systemic vessels ______in response to low levels of oxygen. Pulmonary

vessels ______in response to low oxygen.

Dilate; constrict

  1. The aortic valve is ______in this chart. Compliance is ______in the


Narrowing; decreasing.

  1. What effect does epinephrine and norepinephrine have on heart rate and force of


Increases heart rate and increases the force of contraction

  1. Which is the only hormone that decreases BP?

ANP (atrial natriuretic peptide)

  1. Renin-angotensin-aldosterone mechanism occurs do to what?

A decrease in blood pressure

  1. Renin activates what in the liver? Into what?

Angiotensinogen; angiotensin I

  1. Aldosterone promotes what?

Reabsorption of Na

  1. What effect does aldosterone have on the kidneys if there is low blood pressure?

Increases water reabsorption and decreases urine volume.

  1. What effect does increasing water reabsorption and decreasing urine volume in the

kidneys have on blood pressure?

Increases blood pressure

  1. What type of shock is due to loss of blood or body fluids?


  1. What type of shock is caused by damage to pumping action of the heart?


  1. What type of shock causes a drop in BP?


  1. What do osmoreceptors detect?

Increased osmotic pressure in blood vessels

  1. What term means the failure of the cardiovascular system to deliver enough

oxygen and nutrients?


  1. What type of shock could be due to hemorrhage sweating or diarrhea?


  1. Cardiogenic shock could be caused by what?

MI, ischemia, valve problems or arrhythmias

  1. What type of injury or trauma would cause vascular shock?

Head trauma

  1. ______shock is caused by blockage of circulation (pulmonary embolism)


  1. circulation is left side heart to body & back to heart


  1. ______circulation is capillaries of GI tract to capillaries in liver

Hepatic portal

  1. circulation is right-side heart to lungs & back to heart?


  1. The hepatic portal system is a subdivision off of what circulation system?

Systemic circulation