Bb-bio Lec 9-Heart-gen Circ 6-11 HANDOUTS

8/19/2019 Bb-bio Lec 9-Heart-gen Circ 6-11 HANDOUTS

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The Heart and General Circulation rev 6-11

• The heart and blood vessels are collectivelyknown as the cardiovascular system

• The heart is a hollow muscular organ whose

contractions creates the force and pressure whichmoves blood throughout our body

• The heart is a pump•

t secretes hormones that help regulate blood pressure and the body!s fluid and electrolyte balance"


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$ab %-The Heart and General Circulation

• Arteries carry blood away from the heart• Veins carry blood to the heart• &rteries and veins are connected to each other by

capillaries• The right side of the heart receives returning blood that is low in o'ygen ( deoxygenated )

• *lood moves from the right side of the heart to thelungs where it becomes oxygenated "

• *lood is returned to the left side of the heart whichcirculates it throughout the body


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&natomy of an &rtery, ein and

Capillary• *oth arteries and veins have an inner layer of

simple, s.uamous epithelium cells, a middle layer

of smooth muscle, and an outer connective layer"• Arteries have thicker muscular layers than veins

because they must be able to withstand the high pressures generated by the heart"

• Veins are thinner walled and have valves to helpkeep the blood moving, against gravity, to theheart"


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0 ein valves prevent the backflow of blood"• The smallest arteries are called arterioles the

smallest veins are called venules " These connect

via capillaries"• &ll blood vessels e'cept capillaries have smooth

muscles in their walls"•

Capillaries are a thin layer of s.uamous cellswhich allows for e'change of nutrients, wastesand gases"


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• $ayers of an artery 0 innermost layer is the endothelium

• is a layer of flattened, s.uamous epithelial cellswhich fit so closely together that they create a slick

surface so that blood can flow smoothly" 0 middle layer which is primarily smooth

muscle with elastic connective tissue

0 outermost layer is a supporting layer ofconnective tissue which anchors vessels tosurrounding tissues


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• Veins 0 like the walls of arteries, the walls of veins

consist of + layers of tissue"

• 3uter # layers are much thinner than those ofarteries

• veins have larger diameters than arteries 0

the pressure in veins is much lower than that inarteries which is why their walls are not asstrong as arteries


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0 veins can act as a blood volume reservoir 0 the larger diameter of veins allows them to

stretch to accommodate large volumes of blood

at low pressures 0 because veins can stretch, it is more difficult for

them to return blood to the heart against theforce of gravity

0 people who spend a lot of time on their feetmay get varicose veins because of this


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• Factors which help veins to return blood toheart 0 contraction of skeletal muscles

•as we move and muscles contract and rela',they press against veins and help push bloodto the heart

• one way valves in the veins


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0 the work of the skeletal muscles helps thevalves pump blood" This is called a skeletalmuscle pump

0 movements associated with breathing also help

pump blood" This is called a respiratory pump and helps to push blood from the abdomen tothe chest and to the heart"

• when we breathe, there are pressure changesin the thoracic and abdominal cavities

• during inhalation, abdominal pressureincreases and s.uee es abdominal veins


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• simultaneously, pressure within the thoracic cavitydecreases which dilates the thoracic veins and thus

propels the blood"The Heart

• 8'ternal anatomy-- heart has blood vessels

attached to it 0 the large vessels are the

• aorta which transports blood away from the heart

to the entire body"• the pulmonary trunk (pulmonary vein and

artery) which transports blood to and from thelungs"


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0 The superior and inferior vena cava whichreturn blood to the right atrium

• the 4 chambers of the heart are the 0

# atria9 the right atrium and the left atrium 0 # ventricles9 the right and left ventricles• blood enters the heart through the right atrium,

flows through an atrioventricular valve into theright ventricle


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• :rom the right ventricle, to a pulmonary valve tothe pulmonary artery to the lungs

• o'ygenated blood returns to the heart through the

pulmonary vein• and enters the left atrium• flows through another atrioventricular valve to the

left ventricle• then through another valve to the aorta to the

entire body


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• the heart muscle has its own supply of bloodvessels9 coronary arteries and coronary veins (see

pictures on page 11% of lab manual)• &ll of the chambers of the heart fill at the same

time• note that the pulmonary circulation has the o'ygen

level of the arteries and veins reversed


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0 the heart pumps # ;circuits< at the same time--• the right ventricle to the pulmonary trunk

• and the left ventricle to the entire body 0 the outer wall of the left ventricle is thicker

than the right ventricle

• this ventricle does more work than any otherchamber--it must overcome the pressure ofthe aorta in order to pump blood into it


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=8> ?@8=

• $ook at the bulleted lists on lab manual pages 1#7and 1#1

0 you will need to know where these items arelocated for the lab test

• Ase the models and charts to help you locatethese don!t try to find them in the fetal pig


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n general, blood vessels are named for the bodycavity which they pass through

• The aorta modifies its name as it enters different body areas 0 aortic arch as it leaves heart 0 thoracic aorta9 where aorta straightens out 0 abdominal aorta9 when aorta goes through the

diaphragm 0 after this, the aorta splits to go into each leg it

now becomes the femoral artery


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• >ain arterial branches of the aorta (see page 1#6) 0 brachiocephalic (first branch off aorta) artery 0 carotid artery 0 subclavian (underneath clavicle) artery 0 renal artery (kidney) 0 e'ternalBinternal iliac (ileum hip bones) arteries 0 femoral artery


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• >aDor veins(see page 1#4) 0 superior vena cava

0 inferior vena cava (is the maDor vein in thoracic, pelvic, and abdominal cavities)

0 Dugular vein


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• Eathway of circulation you need to know this 0 follow instructions on page 1#1

• @o the sounds of the heart and the heart rateactivities (page 1#1)


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Functional Anatomy• Contraction of the heart muscle is called systole

0 during systole, blood is pumped out of, oreDected from, the heart into the circulatorysystem

• =ela'ation of the heart muscle is called diastole

0 during diastole, the heart fills with blood


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• *lood Eressure 0 Fhen blood pressure is taken ,

• the higher number is the systolic pressure• the lower number is the diastolic pressure

• ou will be taking each other!s blood pressure withan automatic blood pressure cuff

• wrap the cuff snugly around your partner!s arm(withthe velcro side facing you, not your partner)

• the cuff is placed around the upper part of the arm sothe bottom edge rests immediately above the elbow


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=8> ?@8= page # of +9

/" @o the sounds of the heart and the heart rateactivities

2" Eerform the blood pressure activities on pages1#/-1#2"

6" Fe will also begin dissecting the fetal pig today"=emember that everyone needs to participate inthe dissection"

a" Tie long hair back so it doesn!t mi' with theinside of the pig when you bend down to lookat it"


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=8> ?@8= page # of +9

4" ou need to locate the following endocrine glands9thyroid, thymus, and pancreas (see diagram on page 17/ of the lab manual)"a) @3 N T locate the adrenal glands they are

very hard to find" b) =emember to use Table 11"1 to help you learn

about these glands, their hormones and thefunction of these hormones"

Bb-bio Lec 9-Heart-gen Circ 6-11 HANDOUTS

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