Chapter 13 Blood Vessels and Circulation (Kahoot 13.4-13.9 (Vicki has a…
Chapter 13 Blood Vessels and Circulation
13-1 Blood Vessels
Layers of blood vessels
smooth muscle tissue
inner most layer
endothelial lining of vessels
Arteries (thick tunica media, smaller tunica intima)
diameter of about 30 um, very small
Elastic arteries are large, extremely resilient vessels with diameter of 2.5 cm. or 1in.
Pulmonary trunk, aorta
Muscular arteries are medium-sized arteries or distribution arteries. They distribute blood to skeletal muscles and internal organs. 0.4 cm or .15 in. in diameter
external carotid arteries
Capillaries (Only has tunica intima, single layer of endothelium)
Single layer of endothelium
Only blood vessel whose walls permit exchange between the blood and surrounding interstitial fluid.
Veins (Thinner tunica media, larger tunica intima)
resemble expanded capillaries, diameter smaller than 50
lack tunica media
2mm to 9mm, several smooth muscle layers, thick tunica externa
inculdes 2 vena cava, thin tunica media surrounded by thick tunica externa
The muscular layer of blood vessel is the
Compared to veins, arteries
are more elastic
The blood vessels that carry blood at the highest pressure are
The blood vessels that only have a tunica intima are the
Which of the following blood vessels hold the greatest volume of blood?
Blood flow has the highest velocity in the
The brachial artery would be classified as a
The outermost layer of the arterial wall is the
Which of the following is lesser amount?
The normal blood volume of the arterial system
The vessels that permit exchange of materials between the cells and the blood are termed
13-2 Blood Pressure
factors affecting blood flow
Any force that opposes movement
For blood floe, the circulatory pressure must be great enough to over come the total peripheral resistance, the resistance of the entire cardiovascular system. (about 65 mm Hg)
sources of peripheral resistance include vascular resistance, viscosity, and turbulence
If pressure difference exists, liquid will go from area of higher pressure to an area of lower pressure.
The greater the difference in pressure, the faster the flow.
The largest pressure difference is between the aorta and the right atrium. 100 mm Hg.
arterial pressure (blood pressure)
largest component of peripheral resistance
is the resistance of blood vessels to blood flow
the most important factor is friction between the blood and the vessel walls. The amount of friction depends on the length and diameter of the vessel. Friction increases with increased length and with decreased vessel diameter.
the resistance to floe resulting from interactions among molecules and suspended materials in liquid. Like molasses.
liquids of low viscosity, like water, flow at low pressures, thick, syrupy fluids, like molasses, flow only under higher pressures
Blood has a viscosity about 5x that of water
Anemia, the hematocrit is reduced due to inadequate production of hemoglobin, RBCs, or both. Result, both the O2 carrying capacity and the viscosity of blood are reduced. (Same with protein deficiencies)
Normally, blood flows smoothly with slowest flow near the walls and fastest flow in the center.
High flow rates, irregular surfaces caused by injury or disease processes, or sudden change in vessel diameter upset this smooth flow, creating swirls (turbulence)
turbulence slows flow and increases resistance. Also creates the 3rd and 4th heart sounds.
normally occurs when blood flows between the heart chambers and from heart into the aorta and pulmonary trunk.
Turbulence blood flow across damages or misaligned heart valves produces the sound of heart murmurs.
Interplay between pressure and resistance
Ex. increase in blood flow to a skeletal muscle during exercise. The increase results from a drop in the peripheral resistance of the arteries supplying active muscles.
Of the 3 sources of resistance, only vascular resistance can be adjusted by the nervous sand endocrine systems to regulate blood flow. Viscosity and turbulence, which affect peripheral resistance, are normally constant.
Cardiovascular pressures within the systemic circuit
as blood travels closer to the heart, veins get larger, resistance drops further, and the flow rate increases.
16 mm Hg
which is enough when lying down, when standing 2 factors help propel blood towards heart:
Blood Pressure (atrial pressure)
rises during ventricular systole and falling during ventricular diastole
the difference between the systolic and diastolic pressures is the pulse pressure
lessens as the distance from the heart increases.
elastic rebound is greatest near the heart
by the time blood reaches the precapillary sphincter, no pressure oscillation remain, its about 35 mm Hg.
pressure is 18 mm Hg at start of venous system.
Capillary pressure and capillary exchange: occurs by diffusion, filtration, and osmosis (movement of water from an area of low concentration to an area of higher concentration)
capillary walls are permeable to small ions, nutrients, organic wastes, dissolved gases, and water. most is absorbed by cap. but about 3.6 L water flow through each day entering the lymphatic vessels.
exchange plays important role in homeostasis
capillary exchange 4 important functions
speeding the distribution of nutrients, hormones, and dissolved gases throughout tissues
assisting the movement of insoluble lipids and proteins that can't cross capillary walls
maintaining constant communication between plasma and interstitial fluid
flushing bacterial toxins and other chemical stimuli to lymphoid tissues and organs that function in providing immunity to disease
Which of the following is a normal pressure within capillaries?
20-30 mm Hg
Transport mechanisms used by capillaries include
diffusion, filtration, and osmosis. (all of the above)
As blood travels from the aorta toward the capillaries the
Swelling of a tissue is due to
increased permeability of capillaries.
Which of the following conditions would completely stop all NET filtration?
The blood hydrostatic pressure and the blood osmotic pressure are equal in magnitude but opposite in direction
Blood moves forward through veins
because the pressure in the veins is lower then in the arteries, with the aid of contractions of skeletal muscles, and with the aid of changes in cavity pressure. (all of the above)
Blood flow through the cardiovascular system is affected by
pressure differences, the viscosity of the blood, and the amount of friction in the blood vessels. (all of the above)
The third and fourth heart sounds are caused by
Plasma proteins that remain in the blood capillaries help
maintain the osmotic pressure of the blood.
Edema would be likely to form when
the heart is an insufficient pump.
13-3 Cardiovascular Regulation
smooth muscles of precapillary sphincters respond automatically to certain alterations in local environment, like changes in O2 and CO2 levels or the presence of specific chemicals.
factors that promote the dilation of precapillary sphincters are vasodilators, those that stimulate are vasoconstrictors
monitors the degree of stretch in the walls of expandable organs.
locations: 1) aortic sinuses (in walls of aorta) maintains blood flow for systemic circuit 2) walls of carotid sinuses (neck) maintain blood flow to brain 3) wall of right atrium
initiate baroreceptor reflexes, autonomic reflexes that adjust cardiac output and peripheral resistance to maintain normal arterial pressures.
if BP gets low, inhibition baroreceptor output produces the opposite effects: increase in cardiac output and widespread vasoconstriction. Increases heart rate and stroke volume and cardiac output.
respond to changes in CO2, O2, or pH in blood and cerebrospinal fluid
locations for arterial blood monitoring: carotid bodies (neck near carotid sinuses) and aortic bodies (near arch of aorta)
locations for cerebrospinal fluid monitoring: surface of medulla oblongata
activated by drop in pH or in plasma O2, or by rise in CO2. Activation will elevate arterial pressure and increases blood flow.
formed in blood following the release of enzyme renin by kidney cells in response to fall in BP.
renin starts chain reaction that ultimately converts angiotensinogen into the hormone Angiotensin II (stimulates cardiac output and triggers arteriole constriction, which in turn raises systemic BP)
also stimulates secretion of ADH by pituitary gland and of aldosterone by suprarenal cortex
ADH stimulates water conservation in kidneys
aldosterone stimulates the reabsorption of sodium ions and water from urine
ANGIOTENSIN II STIMULATES THIRST AND ADH AND ALDOSTERONE ENSURE ADDITIONAL WATER CONSUMED WILL BE RETAINED, ELEVATING BLOOD VOLUME.
released at posterior pituitary gland in response to decrease in blood vol., increase in the osmotic concentration of plasma, or presence of angiotensin II
result is vasoconstriction that raises BP and water-conserving effect on kidneys (preventing reduction in blood vol.)
atrial natriuretic peptide
Which of the following factors is most likely to result in an increase in blood pressure?
decrease blood flow to the kidneys
causes a direct increase in blood volume.
Angiotensin (II) increases blood pressure by
increasing peripheral resistance.
Which of the following is greater?
blood pressure when sympathetic stimulation to the heart increases.
Blood pressure in the systemic arteries is the greatest during
When a capillary bed decreases in blood flow due to locally high oxygen levels, it is caused by
Baroreceptors that function in the regulation of blood pressure are located in the
Blood pressure is lowest in which of the following structures?
Which of the following changes will result in increased nutrient delivery to a specific tissue?
relaxation of precapillary sphincters
The baroreceptor reflex causes changes in
blood pressure, stroke volume, and heart rate. (all of the above)
Which of the following will cause a decrease in blood pressure?
increased levels of ANP (atrial natriuretic peptide)
A decrease in vessel diameter is called
13-5 Pulmonary & systemic circuits (describe 3 general functional patterns in the pulmonary and systemic circuit)
2) vessels may undergo several name changes
When an artery goes down the arm its goes from axillary to brachial to radial & ulnar arteries.
3) Tissues and organs are serviced by several arteries and veins
1 organ may have many arteries and veins,not just 1
1) distribution of arteries and veins on left and right are identical
1 brachiocephalic artery, but 2 veins
13-4 Physiological stress
5.8 L per minute at rest
As exercise begins: extensive vasodilation (peripheral resistance drops & capillary flow increases), venous return increases (muscle contractions & increased respiratory rate (pump)), Cardiac output increases (Frank starling principle (ventricle relfex) & Bainbridge reflex (atrial reflex))
Blood donation 500ml 10% (vasomotor enough to restore pressure & flow)
Vebous reserve (venoconstriction) (slow moving blood [liver, bone marrow, & skin], restore 15-20% loss
Sympathetic stimulation (major loss of blood) [E, NE, ADH, Renin]
ADH, aldosterone & increase thirst
Acute circulatory crisis: hypertension, pale, cool, & moist skin, confusion & disoriented (no blood to brain), rapid & weak pulse, no urine, drop in blood pH
have hypotension when in shock
13-6 Pulmonary circuit (identify the major arteries and veins of pulmonary circuit)
capillaries in lungs
L & R pulmonary arteries (deoxygenated blood)
L & R pulmonary veins (oxygenated blood)
13-7 Systemic circuit (identify major arteries and veins of systemic circuit)
aorta (ascending, arch, thoracic, abdominal, abdominal splits into the common iliac arteries)
Branches of the acsending aorta
Right coronary artery, supplies myocardium
Left coronary artery, supplies myocardium
Branches of the aortic arch
axillary, supplies armpit
brachial, supplies upper arm
Right subclavian artery, supplies right arm
radial, supplies lateral forearm
ulnar, supplies medial forearm
palmar arches, supplies palm
digital, supplies fingers
Brachiocephalic, supplies right side of head and right arm
right common carotid artery, supplies right side of head
internal carotid artery, supplies brain
circle of Willis
vertebral, supplies cervical vetrebrae and skull
basilar artery, supplies brain
circle of Willis, supplies brain
external carotid artery, supplies scalp
Branches of thoracic aorta
intercostals, supplies intercostal and chest muscles
superior phrenics, supplies superior diaphragm
bronchial arteries, supplies bronchi of lungs
esophageal arteries, supplies esophagus
Branches of abdominal aorta
celiac trunk, supplies artery
left gastric artery, supplies left stomach
splenic artery, supplies spleen
common hepatic artery, supplies liver
superior mesentric, supplies small intestine, cecum, ascending and transverse colon, and pancreas
inferior phrenics, supplies inferior diaphragm
suprarenals, supplies adrenals
renal arteries, supplies kidneys
gonadal arteries, supplies ovarian and testicular
inferior mesentric, supplies descending and sigmoid colon and rectum
Branches of common iliac arteries
external iliac artery, supplies right and left
femoral artery, supplies thigh
popliteal artery, supplies knee region
posterior tibial artery, supplies lower leg
plantar arteries, supplies heel, foot, and toes
anterior tibial artery
dorsalis pedis artery, supplies foot and toes
coronary sinus, drains cardiac veins
cardiac veins, drains caps of myocardium
hepatic vein, drains hepatic portal system
hepatic portal vein, drains gastric, mesentric, and splenic veins
mesentric veins, drains intestines
splenic vein, drains spleen
gastric vein, drains stomach
Do not drain directly into vena cava, instead they travel to the liver via the portal vein.
superior vena cava, formed by the union of the left and right brachiocephalic veins = head and upper limbs
great saphenous vein
the longest vein in the body,
extends from medial ankle to the external iliac vein
There are 2 brachiocephalic veins.
Only 1 artery. The union of the subclavian and jugular veins on each side forms them.
inferior vena cava, drains veins from abdominal & lower limbs
median cubital vein, venipuncture site
azygous system (azygous vein, right and hemiazygous, left), drains intercostal veins and lumbar veins
jugular veins, drains head
external jugular vein, drains face and scalp
internal jugular vein, drains brain
THESE ARE IDENTICAL TO THE ARTERIES BUT WITH THESE EXEMPTIONS
13-8 Fetal Circulation (identify differences between fetal and adult circulation patterns, describe changes in patterns of blood floe that occur at birth)
placental blood supply
exchange of nutrients
umbilical vein (1)
inferior vena cava
umbilical arteries (2)
rise from internal iliac arteries
fetal circulation in the heart and great vessels
foramen orale, one way valve thru the interatrial septum
ductus arteriosus, pulmonary and aortic trunks
embryonic lungs are collapsed, digestive tract has no food
circulatory changes at birth
foramen ovale closes
ductus arteriosus becomes ligamentum arteriosum
13-9 Aging (effects of aging on cardiovascular system)
reduced cardiac output
changes in nodal or conducting cells
reduced elasticity of fibrous skeleton
aneurysm, stroke, MI, or massive blood loss
thrombi can form at atherosclerotic plaques
construction or blockage (thrombus or embolism)
pooling of blood (valves not working)
After receiving the internal jugular vein, the subclavian vein becomes the
The fusion of the brachiocephalic veins forms the
superior vena cava
Small veins of the brains empty into the
The two common iliac veins form the
inferior vena cava
The vessel that receives blood from below the diaphragm is the
inferior vena cava
Which of the following is a remnant of a fetal blood vessel?
Near the level of vertebra L4, the aorta branches to from the
common illiac arteries
Elderly individuals are more prone to suffer from
hypertension, venous thrombosis, arteriosclerosis, and problems with the conducting system of the heart (all of the above)
divides the aorta into a superior thoracic aorta and an inferior abdominal aorta
Factors that increase the risk of atherosclerosis include
The internal carotids and the basilar artery are interconnected by an anastomosis called the
circle of Willis
Vicki has a disabled posterior pituitary. What type of cardiovascular affects might you expect?
decreased blood volume
In the forearm, the brachial artery becomes the
radial artery and ulnar artery (Both A and B)
In response to hemorrhage, there is
mobilization of the venous reserve
After passing the axilla, the axillary artery becomes the
Symptoms of shock include
hypotension, rapid weak pulse, decreased urine formation, and acidosis (all of the above)
The pulse point on the wrist is actually the
Blood from the face returns to the heart by way of the
external jugular vein
An important artery that supplies blood to the brain is the
Which of the following supplies blood to parts of the intestinal tract?
Superior mesenteric artery
The celiac artery provides blood to the
liver and spleen
Which of the following is greater?
heart rate during cardiovascular shock
over heart rate normally
Which is a branch of the pulmonary trunk?
What are the 5 different types of blood vessels?
artery, arterioles, capillary, venule, vein
What are the 3 layers in blood vessels?
Tunica externa, tunica media, and tunica intima
Which blood vessels have valves?
What 3 things make up peripheral resistance?
viscosity, turbulence, and vascular resistance
Difference between arteriosclerosis & atherosclerosis?
hardening of the arteries, then the other is plaque in arteries makes it hard & focal calcification
What hormones increase blood pressure?
angiotensin II, epinephrine, norepinephrine, aldosterone, EPO, and antidieuretic
What hormones decrease blood pressure?
What forms the inferior vena cava?
the L & R common iliac veins
What forms the superior vena cava?
L & R brachiocephalic veins
What arteries feed the Circle of Willis?
basilar artery and L & R internal carotid arteries