Blood vessels

Where does fluid enter and leave a capillary?

Fluid leaves the capillary at the arteriole end and reenters at the venous end.

Where does the pulmonary circulation begin? Which part of the heart receives the newly oxygenated blood?

The right ventricl pumps through the pulmonary circuit and goes to the left atrium.

Which nervous system not only increases heart rate and force of contraction but can also promote vasoconstriction of systemic arterioles.

The sympathetic nervous system

Difference between arteries and veins regarding flow of blood

arteries - take blood away from heart; veins bring blood to heart

Blood flows from high pressure to low pressure through the following vessels in the pulmonary and systemic circulations.

arteries > arterioles > capillaries > venules > veins

4 types of blood vessles

arteries, arterioles, capillaries, veins (what about venules?)

In which type of vessel would the pressure be the greatest?

arteries; so they have more thick and elastic walls

what is normal hydrostatic pressure at arteriole end of a capillary? What is normal hydrostatic pressure at the venous end of a capillary?

arteriole end of a capillary - normally around 30 mmHg venous end of a capillary - normally around 15 - 18 mmHg

what is shock?

inability of the cardiovascular system to supply the organs of the body with adequate oxygen and nutrients.

Where does systemic circulation begin? Which part of the heart receives systemic blood?

left ventricle is where it begins and ends in the right atrium.

Name structures/tissues of the body that do not have capillaries.

lens and cornea of eye; epidermis of skin; hair, nails, tooth enamel

Where is the second capillary bed located in the hepatic portal circulation? Why is that important?

liver ; it is the body's filtration system; to detoxify blood before it goes back to te heart

where are chemoreceptors located? What do they detect?

located in the carotid bodies, aorta detect oxygen, carbon dioxide, H+

where is blood pressure most commonly measured? What are the units of blood pressure measured in?

the brachial artery; the units of blood pressure are mmHg (millimeters of mercury).

what is the Capillaries function?

the exchange of nutrients and wastes between the blood and the tissues. Nearly every cell in the body has capillaries nearby

What is the systolic pressure? What is the diastolic pressure?

top number; bottom number

In which type of vessel would the pressure be the least?

veins; thats why tunica media is thinner

If a hormone increases sodium in the blood, would it increase or decrease blood pressure?

water follows salt so BP increases as blood volume increases

Arteries near the heart will have what kind of tissue?

will have a lot of elastic tissue (elastic arteries) so that they can accommodate the stroke volume of the heart.

the pressure in veins is very low making it difficult for blood to flow back to the heart (for example, flow of blood from the feet to the heart). There are several factors that aid venous return to the heart:

1. ) valves, 2,) skeletal muscle milking 3.) breathing (change in thoracic pressure

stages of shock

1.) compensatied 2.) decompensated 3.) irreversible

what are the 3 functions of the lymphatic system?

1.)fluid recovery- (draining interstitial fluid by capillary exchange) 2.) immunity, (Peyer's patches and lymph nodes) 3.) lipid absorption (lacteal in villus of GI tract)

4 reasons for edema?

1.)increase in hydrostatic pressure: (most common reason for edema) 2.)decrease in albumin 3.)increase in capillary permeability 4.)lymph drainage blocked

Endothelial cells release chemicals that have important functions including:

1.)reducing friction in blood vessels 2.)vasoconstriction and vasodilation 3.) adhesion of white blood cells

Calculate the mean arterial pressure (MAP) for the above patient: MAP = DP + PP/3 Why is the MAP calculated in this way?

125-80=45 for pulse pressure; then Map =80 + 45/3 map = 80 + 15 ; map = 95

If the pressure is 120/80 mmHg, what is the diastolic pressure?

80 mmhg - bottom number

How does venous hydrostatic pressure increase (in say, someone's feet)?

??????? high venous pressure from standing all day could cause

What happens to blood pressure if stroke volume of the heart increases?

BP increases when stroke volume increases

What would happen to BP if hypoxia (insufficient oxygen in tissues) is detected? Would sympathetic or parasympathetic be stimulated?

BP increases. the low levels of oxygen cause pulmonary arteries to narrow. This squeezes the blood into a smaller space which increases pressure. stimulates sympathetic nervous system. Hypoxia can result in shock.

If blood volume increased from 5 L to 7 L, what would happen to BP?

BP increases; end - diastolic pressure increases; arterial pressure increases, central venous pressure increases

What is microcirculation?

Capillary blood flow (as well as blood flow through smaller arterioles and venules)

Name the two structures connected by the foramen ovale in a fetus. Why does this foramen exist during fetal life? what does it become?

Connects left and right atrium because lungs are not needed. umbilical cord supplies the oxygen. It becomes the fossa ovalis

How does cardiac output affect blood pressure?

If cardiac output increases, BP increases

How does Vasoconstriction of arterioles affect blood pressure?

It increases blood pressure. When arterioles constrict, making it more difficult for blood to flow, resistance to blood flow is increased.

vasa vasorum:

Larger blood vessels have their own blood supply by having blood vessels within their walls. they need it because of thick tunica externa or tunica media.

what determines whether the precapillary sphincters open, allowing blood to flow into the capillary bed?

Local tissue conditions; not all capillaries are filled with blood at all times. blood is sent where cells are active and need nutrients.

where are Nutrients and waste products leaving and entering the capillaries?

Nutrients are carried out at the arteriole end and waste products enter the blood at the venous end.

Calculate the pulse pressure for a patient with a blood pressure of 125/80 mmHg.

Pulse pressure(PP) = systolic pressure(SP) — diastolic pressure(DP) 125-80= 45

How does arteriole diameter (vasoconstriction) affect resistance? If arterioles are constricted, is it harder or easier for blood to flow through them?

Resistance to blood flow is proportional to the l/diameter fourth power (1/d4 ). In other words, if the diameter of a blood vessel is cut in half (vasoconstriction), the resistance will increase by a factor of 16! (vasodilation does the opposite and decreases BP)

Arteriole diameters can change drastically. Why? and where is it controlled?

Small changes in arteriole diameter have a large impact on resistance, making systemic arterioles the key regulators of blood pressure. It is controlled by the vasomotor center in the medulla

what is edema?

Swelling When capillary exchange is not balanced by the drainage of excess fluid, edema results. Edema is an increased amount of interstitial fluid that causes areas of the body to swell.

what two systems does the cardiovascular center control ?

The center can adjust sympathetic and parasympathetic effects on the circulatory system and the heart.

What is an anastomosis?

The connections between two structures with a lumen (usually blood vessels) that provide an alternate route. (like a bypass around a city interstate) can be between artery to artery, vein to vein, or between arteries and veins.

What is a metarteriole?

The end of the arteriole that connects to the capillary

Hterm-0ow does blood vessel length affect resistance? If blood vessels are longer than normal, is it harder or easier for blood to flow through them?

The longer the blood vessels, the higher the blood pressure.

What happens to blood pressure during hemorrhage?

a fall in central venous pressure and cardiac filling brings BP down.

What is a venous sinus? Give two examples.

a valveless irregularly shaped venous channel lined by endothelial cells: examples dural sinus of the skull coronary sinus of the heart

types of capillaries? where found and why?

a. continuous- (junctions between cells) example - nervous tissue, fat tissue and muscle tissue b. fenestrated (pores, leakier) kidneys, glands, sm. intestine c. sinusoids (larger spaces btwn cells- most leaky) i.e. Liver, btwn epithelial cells, spleen, lymp nodes

What are three major factors that affect the total peripheral resistance (TPR):

a. vasomotor tone b. viscosity of blood c. blood vessel length While all three factors are important, the total peripheral resistance (TPR) is controlled primarily by (a) arterioles through changes in their diameter.

Name conditions that cause precapillary sphincters to open.

a.) low oxygen b) high carbon dioxide c) high H+ d.) ??

Why is collateral circulation a benefit for the tissues?

allows oxygen to reach tissues where vessels are blocked and help them survive or recover

Name the average pressure in each of the vessels listed below: Vessel Pressure (mmHg) aorta, pulmonary artery, arteriole, capillary, vein

aorta - 100 mmhg, pulmonary artery - 15 mmhg, arteriole 85-35 mmhg (Note that pressure can vary greatly in the arteriole depending on whether arterioles are dilated or constricted), capillary 35-25 mmhg, vein -5 mmhg (venule 15mmhg)

Place the following in the correct sequence: superior mesenteric vein, central vein, capillary in blood vessel of villus, hepatic vein, hepatic portal vein, superior mesenteric artery, inferior vena cava, aorta

aorta>superior mesenteric artery >

What would be the net filtration pressure on the arteriole end? What would be the net filtration pressure on the venous end? Why would edema develop in this case?

arteriole end venous end

Venous pressure is normally around 15 mmHg. What would happen if venous pressure increased to 25 mmHg?

arteriole end venous end hydrostatic p osmotic p hydrostatic p 35 mmHg 22 mmHg 25 mmHg

between the normal hydrostatic and osmotic pressure what would that make a capillary at each end?

at arteriole end: 30 mmHg (hydrostatic) pushing out vs. 22 mmHg (osmotic) pulling in result: 8 mmHg pushing out at venous end: 15 mmHg pushing out (hydrostatic) vs. 22 mmHg (osmotic) pulling in result: 7 mmHg pulling in

Why is the pulse measured on an artery and not a vein?

because arteries can stretch and have elastin

Why does The pulse rate typically reflects the heart rate

because the pulse is created by systole and diastole of the heart.

Why are baroreceptors located in the carotid sinuses?

because they respond to stretch

What would happen to BP if the chemoreceptors detect high CO ? Does acidosis affect blood pressure?

blood pressure increases to get rid of CO2 faster. acidosis causes vasoconstriction which makes blood pressure go up.

How does blood volume affect blood pressure?

blood volume affects arterial pressure by changing cardiac output.

6 factors that affect blood pressure (BP)

blood volume, cardiac output, chemoreceptors, baroreceptors, peripheral resistance, hormones

Which vessels do we have the most of?

capillaries have the greatest cross sectional area because even though they are small we have so many of them.

decompensated shock: What signs would be observed?

cardiovascular system can no longer maintain sufficient cardiac output blood pressure - lowered heart rate - lowered

what is compensated shock and what signs would be observed/

compensated: increase in sympathetic nervous system stimulation body is experiencing low blood volume blood pressure, - increased initially type of pulse, - increased heart rate, - increased skin, - pale or gray urine production, - reduced flow why might the patient be sweating (anxiousness and epinephrine causes person to be sweaty. clammy)? pH of blood Blood vessels - too acidic which will cause rapid breathing to try to rid of CO2

Which two structures are connected by the ductus arteriosus? What is the purpose of the ductus arteriosus?

connects the pulmonary artery to aorta in fetus. bypass the lungs. after birth it becomes the ligamentum arteriosum.

what happens in irreversible shock?

damage to major organs makes it irresverible

what is arteriovenous anastomosis?

direct artery to vein connection

what is pulse?

elastic arteries expand and recoil with systole and diastole

what are the 2 histoloical parts of the capillaries

endothelium and basement membrane

Arterioles consist of ( 3 histological parts)

endothelium, a basement membrane, and smooth muscle cells.

At any given time, where is the most blood is found?

in veins (approximately 60-65% of the blood volume

Where does blood flow fastest and slowest and why?

fastest in arteries (just leaving heart); slowest in capillaries ( for nutrient exchange) ;

The umbilical artery carries blood from what to what? Is the blood in the umbilical artery oxygenated or deoxygenated?

fetus to placenta. it is deoxygenated and one of only 2 "blue" arteries. (pulmonary is the other one- because they are both leaving heart)

Why does a person who gains weight have longer blood vessels?

for every pound of weight we put on 5 miles of blood vessels. the nutrients have to reach those tissues.

Explain why the circle of Willis is an important anastomosis.

great clinical significance because it protects the brain from ischemia by having a circle of alternate routes for oxygen to reach the brain

Capillary exchange is regulated by pressures. what are two pressures involved in capillary exchange:

hydrostatic pressure: - pressure pushing out on the wall of the capillary osmotic pressure: pressure pulling water into the capillary due to albumin and Na+ in blood.

some common types of shock What is the cause of each? hypovolemic shock, neurogenic shock, septic shock ,obstructive shock, anaphylactic shock, cardiogenic shock,

hypovolemic shock, - neurogenic shock, septic shock , obstructive shock, anaphylactic shock, cardiogenic shock,

Where is the cardiovascular center regulated?

in the medulla oblongata

Blood flow through capillaries is

intermittent.

What is the effect of epinephrine (adrenaline) on blood pressure?

it causes nasoconstriction so BP increases

What happens to blood pressure in polycythemia vera?

it is an increase in RBC's circulating in the bloodstream. Makes blood thicker, harder to pump and blood pressure increases

Why is this called the "pulse" pressure? What type of pulse will a patient have who has a high pulse pressure?

it is due to the stroke volume entering the aorta (stretch) and then recoiling when it relaxes. the pulse wave is sent through the elastic arteries.

Does capillary exchange stay in balance?

it is not in perfect balance. More fluid leaves the capillary than reenters. Even some albumin can leak out. This fluid (interstitial fluid) is channeled back into the blood via the lymphatic system

What is the meaning of portal circulation?

it means the vein is located between two capillary beds

In order for the right ventricle to pump blood into the pulmonary artery,

it must create a greater pressure than in the pulmonary artery.

In order for the left ventricle to pump blood into the aorta,

it must create a greater pressure than the pressure in the aorta

what would happen If the albumin moves to the interstitial fluid?

it would pull water into the interstitial space. An increase in capillary permeability can be seen in systemic infections.

What happens when the baroreceptors detect low pressure? Will the parasympathetic or sympathetic nervous system be stimulated?

low pressure causes increase in stimulation of sympathetic nervous system to increase heart rate

Why is the tunica media thinner in a vein than in an artery? Why is the tunica externa thicker in a vein than in an artery?

media thinner in vein because blood pressure not as great as in artery ; externa thicker because it is a connective tissue layer that holds vein open by connecting to surrounding structures

Is acidosis an example of positive feedback or negative feedback?

negative ??

what is peripheral resistance? Does greater total peripheral resistance increase or decrease blood pressure?

opposition to the flow of blood; it increases blood pressure

If albumin is decreased, what happens to osmotic pressure?

osmotic pressure decreases.

If lymph cannot flow freely, the excess interstitial fluid from capillary exchange will accumulate. what are two examples of this?

parasite like in elephantitis and removal of lymph nodes like in cancer patients.

umbilical vein carries blood from what to what?

placenta to fetus. It is oxygenated (red)

Capillary blood flow is regulated by

precapillary sphincters (vasomotion) located at the metarterioles

Veins have valves. What is their purpose?

prevent backflow; skeletal muscle milking squeezes blood past the valves.

give an example of a place in the body that has collateral circulation.

radial and ulnar arteries to the hand

Name the four major arteries that lead to the brain and form an anastomosis in the circle of Willis.

right and left internal carotid artery; anterior cerebral artery, middle cerebral artery

What is normal osmotic pressure throughout the capillary?

should be constant (approximately 22 - 25 mmHg). Because Albumin (a protein) does not leave the capillary

What type of epithelium is present in endothelium? Why?

simple squamous because diffusion of gases and small molecules allows for easy absorption of nutrients and waste removal. Also slick so platelets won't stick.

Why do Capillaries have the slowest blood flow.

slowest to ensure time for exchange of nutrients. The speed of blood flow is inversely proportional to the total cross section of the vessels. In other words, blood flows slowest through the vessels with the largest cross sectional area.

Where is the first capillary bed located in the hepatic portal circulation?

stomach and intestines; picks up nutrients and toxins

Generally, what two blood pressure measurements are taken? what does each mean?

systolic and diastolic pressure. The systolic pressure is the pressure in the artery when the ventricles contract and pump the stroke volume into the artery. The large elastic arteries will stretch to accommodate the stroke volume. The diastolic pressure is the pressure in the artery when it recoils and relaxes.

what are the pulse points? Which are most commonly used to find a pulse?

temporal, common carotid, brachial, femoral, popliteal, posterior tibia', dorsalis pedis arteries

which endothelium will have folds when looked at under the microscope?

the artery due to the tone of the smooth muscle

BLOOD PRESSURE

the force of the blood (hydrostatic pressure) on the wall of a blood vessel

How does viscosity affect resistance? If blood is thicker (high viscosity) is it harder or easier for blood to flow?

the greater the viscosity the greater the resistance. harder to flow. BP increases

If the arteries near the heart were not elastic and had to accommodate the stroke volume, would you expect the systolic blood pressure to go up or down? Why?

the systolic BP would go up because the resistance in the artery that can't stretch would create higher blood pressure as it is forced through an artery that is more narrow.

What does a pressure of 125/80mmHg mean?

the top number is the pressure on the wall of the blood vessel when the ventricle is contracting and the bottom number is the pressure when the ventricle is relaxing

Where in the brain is arteriole diameter controlled?

the vasomotor center (of medulla oblongata)

Why is the smooth muscle layer generally thicker in arteries than in veins?

to withstand the higher pressure within the artery

arteries: three histological layers

tunica interna: endothelium + layer of elastic tissue tunica media: elastic fibers and a thick smooth muscle layer tunica externa: elastic and collagen fibers

Is the systolic pressure always higher than diastolic pressure?

usually because it is the number for when the ventricle is contracting, but if diastolic pressure is usually high the systolic often goes up over time.