meow part 2

hematocrit

the red part of your blood and what dictates if you have anemia or polycythemia

composition of blood

water, plasma proteins

transport proteins - allows for transport of molecules not normally carried by water

clotting proteins - clot using erythrocytes and platelets

immunogloblins - antibodies, fight infection

peptide hormones

function of cells

erythrocytes - oxygen transportation, hemoglobin gives rust color

leukocytes - protective cells; granulocytes/agranulocytes. granulocytes contain membrane bound granules

leukocyte types

neutrophils - first responders, starts inflammatory response, usually killed in large numbers because they are the first to come. seen in pus along with dead bacteria

eosinophils - parasitic infection, also common in ppl who are fighting off severe allergies

basophils - can release histamine like mast cells

monocytes - mature into macrophages, roaming protectors that eat bacteria, can also function as antigen presenting cells of adaptive/immune response

lymphocytes - adapted to immune system, can become t or b cells depending on where they mature in body (b for bone marrow, t for thyroid)

thrombocytes/platelets - megakaryocyte that breaks to form platelets which help in clotting

hemostasis

1. vascular spasm - blood vessel constricts to prevent blood loss

2. platelet plug formation - platelets form soft plug

3. coagulation - plasma proteins (fibrin) makes cloth tough enough to withstand time for repair

heart enclosed by..

pericardium, pericardium is enclosed by pericardial sac. parietal pericardium is made of aerolar tissue and mesothelium. percardium + sac prevents trauma from messing up your heart(beat).

3 layers…

• epicardium - visceral pericardium

• myocardium - bundles of cardiac muscle, also contains cardiac skeleton (connective tissue) THE MOST CRUCIAL LAYER OF ALL!!! actually does contracting and pumping

• endocardium - innermost layer of heart, consists of endothelium which is continous with blood vessels

Auricles

appendages that allow for atrial expansion

Coronary/Anterior and Posterior interventricular sulcuses

Coronary - marks ventricular-atrial boundary

Anterior/Posterior Interventricular - mark boundary between ventricles

Circulation

Pulmonary Circulation - Lung-based, whole point is to oxygenate the blood. Shorter circuit, deoxygenated blood goes to lungs and back to heart to pump to rest of the body. Right side of heart + pulmonary artery/veins

Systemic Circualation - Focuses on supplying oxygenated blood to organs, muscles, etc. Goes through whole body, gets deoxygenated at end of the cycle. Deoxygenated blood goes through heart and starts the pulmonary circulation. Left side of heart + aorta/vena cavas

Circulation (Atriums and Ventricles)

• Right Atrium - COLLECTS deoxygenated blood FROM systemic circuit

• Right Ventricle - PUMPS deoxygentaed blood TO pulmonary circuit

• Left Atrium - COLLECTS oxygenated blood FROM pulmonary circuit

• Left Ventricle - PUMPS oxygenated blood TO systemic circuit

Atriums collect, ventricles pump. Left focuses on deoxygenated blood, right focuses on oxygenated blood

Right Atrium

Collects blood from…

• Superior Vena Cava

• Coronary Sinus

• Inferior Vena Cava

Right Atrium wall has PECTINATE MUSCLE

get a load of this guy

Valves

• Tricuspid - controls from from R. Atria TO L. Atria

• Bicuspid - controls flow from L. Atria TO L. Atria

Prevents backflow, closed when ventricles conctract. Flaps are fibrous dense connective tissue covered by endocardium

Flow of R. V

Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Semilunar Valve → Pulmonary Trunk

Structures of Ventricles

• Trabeculae Carnae - Muscular ridges on walls,

• Chordae Tendinae - CT attached to flaps of valves to pull

• Papillary Muscles - Prevents prolapse of AV flaps, controlled by MODERATOR BAND

Left Atrium

Recieves OXYGENATED blood from pulmonary veins (left AND right)

Flow of L.V

Left Atrium → Bicuspid Valve → Left Ventricle → Aortic Semilunar Valve → Ascending Aorta

Difference between L.V and R.V

Left Ventricle has thicker muscle because it needs to pump blood through much more blood vessels than the right, which only has to pump to the lungs which is only 6 inches away.

bonus

When ventricles relax, semilunar valves are CLOSED. When they contract, semilunar valves are OPEN

Heart Murmur

When something wrong with valves (invert), blood squeeze through valve and creates odd noise instead of the traditional “lub” (AV closing) “dub” (semilunar valves closing).

Heart Supply (Arterial)

From Aorta - Coronary Arteries (Left and Right): Arterial branches that supply myocardium with oxygenated blood.

• Right CA - Posterior interventricular artery, marginal artery

• Left CA - Anterior interventricular artery, circumflex artery

Heart Supply Venous (Cardiac Veins, return deoxygenated blood to the right atrium)

Coronary Sinus takes blood from…

• Middle/Small/Great Cardiac Vein

Neonatal Circulation

Starts from placenta to the umbilical cord (artery and vein). Blood is mixed, deoxygenated AND oxygenated. Foramen Ovale in heart mixes blood between the atriums, closes up once born. Ductus Arteriosus is a short muscular blood vessel connecting pulmonary trunk with aorta, mixes blood from ventricle with aortic arch.

Contractile VS Conducting Cells

Contractile - Shortens to produce the mechanical force required to pump blood; [cardiac muscle]: other cardiocytes connected via intercalated discs (in syncytium), 25% of cell volume is mitochondria (many)..

Conducting - Produces action potentials to tell cardiac muscle to contract

Conducting Cells

Automatically rhythmic without nervous system innervation (autonomic nervous system, brain can only tell to speed up or slow down)

Initiate cardiac AP

Sets heart rate

Propagate signal from atria to the ventricles, atra contract followed by ventricles

Conducting System Structures

SA Node - Contains pacemaker cells, depolarize first, set heart rate. Pacemaker, tells atria when to fire

AV Node - Junction between atria and ventricles, listens to SA Node for when to contract ventricles. Connected to SA by Internodal pathways

Bundle of His - Unites atria and ventricles

Purkinje Fibers - Sends impulse to ventricular cardiac muscles

Moderator Band

Conduction begins with AP at SA node, transmitted through entire conducting system, produces contraction in contractile muscle cells, studied via EKG.

SA → AV → Bundle of His → Bundle Fibers → Purkinje Fibers

Heart Rate

Determined by SA nodal cells, recieve innervation from both sympathetics and parasympathetics. EPINEPHREINE (increase) AND ACETYLCHOLINE (decrease)

3 Phases of SA Nodal AP

Pacemaker Potential - gradually depolarizes towards threshold; caused by HCN (funny current) Na channels, opens due to repolarization… caues influx of Na+. Depolarize the membrane potential on their own, NO REST
Depolarization - Threshold is reached causing cell to depolarize, mostly driven by T-Type (Transient type) Ca2+ channels

Repolarization - Cell repolarzied due to opening of voltage gated K+ channels, repolarization causes HCN channels to open and cause pacemaker potential

EKG

Electrical events of heart, typically series of 4 to 12 leads at specific body locations

Blood Volumes

End Diastolic Volume - Volume of blood in ventricles AFTER diastole

End Systolic Volume - Volume of blood in ventricles AFTER systole

Stroke Volume - Volume of blood ejected by ventricles during diastole

SV - DV = ESV

Cardiac Output

Voume pumped by left ventricle in 1 minute (CO = HR x SV)

CO = Cardiac output

HR = Heart rate

SV = Stroke volume

Typical output is usually 5 liters per min

SV can be affected by filling time and venous return

Factors affecting HR

Atrial (Brainbridge) Reflex: Increased venous return stimulated stretch receptors in wall of atria, which activates sympathetics

Autonomic Innervation: Medulla oblongata (cardio center), sympathetics, parasympathetics

Hormones like Epinephreine, thyroxine

Frank Starling Principle

As EDV increases, stroke volume increases. More you get in, more you get out. Rest = low EDV, myocardium expands less. Exercise - high EDV, myocardium expans more. Physical limits.

Factors affecting ESV

Preload - ventricular stretching during diastole, proportional to EDV

Contractility - force produced during diastole at a given preload. affected by ANS. epinephrine increases contractile force.

Afterload - tension ventricle needs to produce to open the semilunar valve and eject blood. increased by any factor that block arterial flow

Heart Disease

Coronary artery disease (cad) - partial/complete blockage of coronary circulation, results from atherosclerotic plaque

• symptoms - Angina pectoris (common 1st symptom), temporary sensation of pain, chest constriction, or pressure radiating from sternum to arms, neck and back during workload. Myocardial infarction, heart attack. coronary artery blocked, leading to oxygen starved area of tissue, this area is called an infarct.

Treatments: anti-coag (aspirin, coumadin), beta blockers (propranolo, metoprolol), vasodilators (nitroglycerin), calcium channel blockers (amlodipine, nifedipine), atherectomy, balloon angioplasty, coronary artery bypass graft

Classes of blood vessels

Arteries - carry blood away from heart (oxygenated except for pulmonary)

Arterioles - smallest branches of arteries (oxygenated)

Capillaries - site of exchange between blood and interstitial fluid (start as oxygenated, but by the end they’re deoxygenated)

Venules - collects blood from capillaries (deoxygenated)

Veins - return blood to heart (deooxygenated, except for pulmonary)

Artery

Usually round lumen, tunica intima had rippled endothelium and internal elastic membrane. Thick tunica media, external elastic membrane. Lumen is round because there’s much more pressure in arteries than veins. This is why we don’t draw blood from arteries, due to their blood pressure.
Function: Elasticity - allows arteries to absorb pressure waves that come with each heartbeat
Contractility - Allows artiers to change diameter (tunica media) controlled by ANS

Elastic Arteries - Large vessels like aorta and pulmonary trunk, tunica media has more elastic fibers, elasticity evens out pulse force

Muscular Arteries - Medium-sized, much more muscle in tunica media than elastic fiber

Arterioles

Smaller than artery, little to no tunica media, epinephrine causes vasoconstriction

Venules

Small, incomplete veins. Receive blood from capilarries, send blood to veins. Mostly endothelium and thin tunica media, porous like capillaries. (example; inflammatory response).

Vein

Usually flattened/collapsed lumen, tunica intima has smooth endothelium and no true intenral elastic membrane. Less muscle in tunica media.

Great compliance, function as blood reservoirs, larger in diameter than arteries, have thinner walls than arteries, lower blood pressure, venous blood moves from venules to medium-sized veins, then to large veins.

Has venous valves, folds of tunica intima that prevent blood from flowing backward due to low pressure which would make it harder to work against gravity. Compression pushes blood toward heart.

Blood distribution

60% in veins/venules

15% is in arteries/arterioles

12% in pulmonary blood vessels

8% in heart

5% in capillaries

Capillaries

Exchange between blood and interstitial tissues, consists of tube of endothelium with thin basement membrane, capillary beds found in all tissues except cartilage, cornea, and superficial epithelia.

Capillary Networks: Beds - ~10 to 100 capillaries connect one arteriole with one venule

Precapillary sphincter - guards entrance to each capillary, opens and closes causing capillary blood flow in pulses

Thoroughfare channels - capillaries connect an arteriole and venule, controlled by smooth muscle segments on metarterioles

3 types of capillaries -

Continous: small pores, permit diffusion of water, small/lipid soluble materials. blocks blood cells and plasma proteins, abdundant in skin and muscles. allows oxygen to leave.

Fenestrated: medium pores, more permeable, permit exchange of water and small blood proteins. used for absorption and filtrate formation. found in choroid plexus, endocrine organs, and kidneys.

Sinusoidal: large pores, exchange of large plasma proteins but NOT erythrocytes, slower blood flow (allows modifcation), macrophages in lining monitor blood stream and phagocytize bacteria, found only in liver, bone marrow, spleen, and adrenal medulla

Capillary exchange

Capillary hydrostatic pressure: favors leaving blood, water wants to leave (pressure that water is exterting on walls of the blood vessel

Blood/colloid osmotic pressure: favors getting in blood, water gets pulled in. the more concentrated your blood is (the less water there is), there’s more osmotic force/pressure extering into your blood. the more dilute your blood is, the weaker the osmotic pressure exerting into your blood.

Net filtration pressure (NFP): amount of force that fluid flows into or out of the capillary (NFP = hydrostatic pressure - blood osmotic). If total pressure favors LEAVING capillary, filtration occurs. If total pressure favors entering capillary, reabsorption occurs.