Human Anatomy Unit 3

Third Unit of Human Anatomy

Heart

pumps blood

Artery

any vessel carrying blood AWAY from the heart

Vein

any vessel carrying blood TOWARDS the heart

Four Heart Chambers

Right atrium, right ventricle, left atrium, left ventricle

Path of deoxygenated blood

enters right atrium => right ventricle => pumped out into lungs

Path of oxygenated blood

enters left atrium => left ventricle => pumped out into body

pulmonary circut

route between heart and lungs that allows blood to pick up oxygen: right ventricle => pulmonary trunk/arteries => lungs => pulmonary veins => left ventricle

systemic circut

route between heart and tissues of the body (other than lungs): left ventricle => aorta & branches => cells of body => veins

Gallons of blood pumped every day

1800

miles of blood vessels

60,000 miles

Where the heart sits

left of midline, on top of diapragm

Pericardium

sac containing heart; collagen fibrous structure, well attached to surroundings

Layers of heart outside => in

fibrous pericardium => serous pericardium => myocardium => endocardium

fibrous pericardium composition

dense irregular connective tissue (anchors heart)

serous pericardium/epicardium

parietal and visceral layers with serous fluid for lubrication

myocardium composition

cardiac muscle tissue

endocardium epith type

simple squamous

superior & inferior vena cava

large veins that return deoxygenated blood to right atrium

tricupsid valve

separates right atrium from right ventricle

chordae tendinae (right)

dense regular CT that attaches cusps of tricupsid valve to ventricle wall

papillary muscles

projection of cardiac muscle

pulmonary semilunar valve

separates right ventricle from the pulmonary trunk (artery)

pulmonary veins

return oxygenated blood 

bicupsid/mitral valve

separates left atrium from left ventricle

chordae teninae (left)

dense regular CT that attaches cusps of bicupsid valve to ventricle wall via papillary muscle 

aordic semilunar valve

separates left ventricle/aorta

Myocardium

the muscular layer of the heart wall that contracts to pump blood; thickest in the left ventricle because it must pump blood to the entire body.

tricupsid/bicuspid

named by # of cusps per valve. chordae tendinae prevent valves from inverting into atria when ventricles contract

pulmonary & aortic seminlunar valve

cusps resemble pockets. as ventricles contract, blood is pushed up against semi-lunar valves

heart murmur

Noise in heart caused by blood leaking past closed valve

Mitral valve prolapse

most common cause of heart murmur; weakness in collagen of valve or chordae tendinae

stenosis

(Heart murmur): narrowed opening between valves, may be caused by calcium deposits or illness

Cardiac muscle cells

Conduct electrical impulse through myocardium of heart wall

Gap junctions

Allow for quick communication between cells; coordinated contraction

Fascia Adherens

desmosome-like connections that provide strength

Sinoatrial (SA) node

in the right atrium, initiates electric impulse

Atrioventricular (AV) node

delays impulse before it is passed to the ventricles. This delay is to allow the ventricles to fill with blood. 

internodal pathway

carries impulse from SA node to AV node

pacemaker

inherent rhythmicity (automaticy)

fibrous skeleton

barrier between atria and ventricles that prevents electrical impulse from passing

AV Bundle

space between ventricles => bundle branches into ventricle walls => perkinjie fibers

top to bottom

atria contract

bottom to top

ventricles contract

purkinjie fibers

specialized cardiac muscle cells that rapidly conduct electrical impulses throughout the ventricles

cardiac cycle

1 heart beat, ~ 0.8 seconds

systolye

contracting

diastole

relaxed

Stage 1 of Cardiac Cycle

atria contract/push blood into ventricles (atria are always filling)

Stage 2 of Cardiac Cycle

ventricles contract/atria rest

Stage 3 of Cardiac Cycle

Atria and Ventricles at rest

Right & Left Coronary Artery/Branches

supply oxygen to OUTSIDE of heart

Anterior Interventricular Artery

a major branch of the left coronary artery that supplies blood to the front of the heart

Atherosclerosis

Build up of plaques which cause narrowing of artery

myocardial infarction

heart attack => result og blood not reaching cardiac muscle tissue

Thrombus

Blood Clot

Ischemic

restriction in blood supply resulting in O2 and glucose deprivation in tissues

Balloon  Angioplasty w/ Stent

opens vessel wall to hold open artery (1-2 blockages)

Coronary Bypass

cut through the sternum, take leg vein, attack it to aorta and downstream of blockage

Blood Vessels

organs => transport blood. Continuous circut between heart and capillaries

lymph vessels

transport lymph fluid

layers of blood vessels

Tunica intima, tunica media, tunica externa

tunica intima

innermost, endoepithelium, simple squamous. subendotheliar: loose areolar

tunica media

smooth muscle arranged circularly to allow for vasoconstriction. Thicker w more elastic fiber in arteries due to higher bp

tunica externa

loose areolar CT

Vaso vasorum

blood vessels that supply O2 to other blood vessels

Vein Vavles

Tunica intima forms valves to prevent backflow

elastic arteries

largest. branches bear heart. high concentration of elastin. recoils quickly when bp drops. 

Muscular arteries

branch off elastic arteries. serve organ or region of organ. control how much blood goes into an organ. 

arterioles

branch off muscular arteries. constrict/dilate quickly to help regulate blood flow to cap. larger: all three tunicas + elastic lamina. Smaller: tunica media and endothelium only.

capillaries

diameter of one RBC. no tunica media/externa. thin for diffusion of gas. form capillary beds.

portal system

blood passes through two capillary beds before returning to heart

venules

larger venules have all three tunics (though thin), while smaller ones consist mainly of endothelium and a thin tunica externa

medium veins

collect blood from venules and return it to large veins; they have all three tunics, a thicker tunica externa than media, and contain valves to prevent backflow under low pressure.

large vein

all three tunics with a very thick tunica externa rich in collagen and elastic fibers, a thin tunica media, and valves in some regions to aid blood return to the heart.

precapillary sphincter

controls amount of blood moving through capillary bed. smooth muscle

postcapillary venule

located right after the capillaries — they collect blood leaving the capillary beds

metarteriole

short vessel that links an arteriole to a capillary bed, acting as a thoroughfare channel that can bypass capillaries when precapillary sphincters are closed

capillary walls

thin to allow for exchange; endothelium + basement membrane.

3 types of capillaries

continuous, fenestrated, sinusoidal

continuous capillary

least leaky, most common, tight junctions, intercellular clefts (at areas w no cell junction) and complete basement membrane

fenestrated capillary

high rate of molecular exchange. pores => fenestrations. complete basement membrane

sinusoidal capillary

special fenestrated cap. large passings (proteins, blood cells). large intercellular cleft and incomplete basement. most leaky. fewer tight junctions. located in places like spleen, bone marrow, lymph nodes.

varicose veins

failures of valves cause blood to pool causing veins to stretch and become misshapen.

blood

distributes O2, removes CO2, transports nutrients, waste, hormones, etc. Regulates body temperature and pH. prevents infections.

formed elements

cellular components of blood

erythrocytes

red blood cells. 45%. concave disc. no organelles. anaerobic. 97% hemoglobin. 3-4 month lifespan

buffy coat

leukocytes and platelets. <1%

Plasma

mostly water but also wastes, nutrients, hormones, and proteins: fibrinogen & albumin. 55%

fibrinogen

blood clotting protein in plasma

albumin

binds above solutes, protein in plasma

blood clots components

fibrin, platelet aggregates, rbcs

hemoglobin

binds gasses (O2 and CO2)

anaerobic

doesn’t need to use O2, uses glucose

megakeryocytes

very large cells, their fragments => platelets

hemotopeisis

new RBCs form from stem cells in red bone marrow. Fe NEEDED for this and hemoglobin.

Anemia

lower # of RBC’s, commonly due to Fe defficiency

diapedesis

can squeeze through capillary walls. immune response

A, B, Rh

glycoproteins

Antigens/agglutinogens

determines blood type

type A blood

A antigens only,produces antibody B