a&p unit 10: hematology and cardiology

blood/blood cells function

transporting oxygen from the lungs to tissue cells and carbon dioxide from tissues to lungs

blood volume

5 liters: 45% formed elements, 55% liquid plasma

solid cells/”formed elements”

mostly RBC, referred to as hematocrit

liquid plasma

contain nutrients, electrolytes, and proteins

erythrocytes

RBC; carry oxygen, biconcave discs, contain hemoglobin, anucleaute

leukocytes

WBC; protect against disease, 5 subtypes

thrombocytes

platelets; involved in clotting, not cells, but fragments of giant cells called megakaryocytes

hemolysis

RBC destruction, liver and spleen macrophaged destroy worn RBC’s, hemoglobin is broken into globin and heme

what does biliverdin turn into during hemolysis

bilirubin → bile

erythropoiesis

RBC production, negative feedback involving the hormone erythropoietin

where does erythropoiesis occur in adults

red bone marrow

what is needed for erythropoiesis to occur

iron, B12, and folic acid

leukocytes

WBC’s that originate in red bone marrow from hematopoietic cells then circulate in blood

granulocytes

WBC, granular cytoplasm, “spotted cells”, granules are sacks of enzymes

neutrophils

engulf pathogens by phagocytosis, increase during bacterial infection, become engorged with toxins and die

eosinophils

attracted to parasites (worms), involved with allergic reactions

basophils

release heparin and histamine, play a role in allergic reactions

agranulocytes

agranular cytoplasm

monocytes

phagocytosis of large particles, differentiate into macrophages when they migrate from the blood stream, half are stored in the spleen

lymphocytes

key to the immune system, produce antibodies that attack foreign substances, differentiate into T-cells and B-cells

hemostasis

the stoppage of bleeding from a blood vessel

hemostasis steps

1. blood vessel spasm (vasospasm)

2. platelet plug formation - platelets release serotonin and thromboxane

3. blood coagulation (clotting) - PF3 converts prothrombin into thrombin, and thrombin cuts fibrinogen into fibrin

clot removal

vessel repair begins, epithelial cells undergo cell division to fill gap, fibroblast secrete CT to repair basement membrane

blood antigens

determine blood group, located on RBC

blood antiboides

located in plasma, made by immune system to remove foreign antigens

blood clotting

mixing blood leads to clumping, occurs when receiver of blood has antibodies against the donor blood cells

type A compatible donors

A and O

type B compatible donors

B and O

type AB compatible donors

AB, B, A, and O

type O compatible donors

O

what makes type AB special

its the universal recipient

what makes type O special

it is the universal donor

visceral pericardium

innermost layer of the pericardium that directly covers the heart

parietal pericardium

middle layer of pericardium that forms a protective layer around the heart

fibrous pericardium

outermost layer of pericardium, prevents stretching

coverings of the heart from innermost to outermost

visceral, parietal, and fibrous

epicardium

outer layer of the heart wall, protects the heart

myocardium

thick middle layer, cardiac muscle tissue (bulk of the heart)

endocardium

thin inner layer of heart wall, lines chambers and valves

two atria

upper chambers of the heart that receive blood from the body and lungs

two ventricles

lower chambers of the heart that pump blood to the lungs and body

heart septum

muscular wall that separates the left and right sides of the heart

pulmonary circuit

pathway of deoxygenated blood through heart and lungs

systemic circuit

sends oxygenated blood to all body cells and removes waste

cardiac cycle

series of events associated with one heartbeat

systole

phase of heart contraction

diastole

phase of heart relaxation

“lubb” heart sound

AV closing

'“dupp” heart sound

SL closing

average BP

120/80

murmur

abnormal heart sound

120

systolic #, blood forced through arteries

80

diastolic #, pressure in arteries when heart is at rest

cardiac conduction system

specialized tissue that runs electricity through the heart (causes the heart to beat)

first CCS step

sinoatrial node - pacemaker, sets the pace of heart, both atria contract

second CCS step

atrioventricular node - relays electrical impulses from the atria to the ventricles

third CCS step

atrioventricular bundle - conducts impulses into the ventricles, dividing into right and left bundle branches

fourth CCS step

right and left bundle branches - transmit impulses downward toward apex

fifth CCS step

Purkinje fibers - distribute impulses throughout the ventricles causing them to contract, located in papillary muscles

ECG

measures electrical change of the heartbeat during a cardiac cycle

P wave

atrial depolarization (contraction), triggered by SA node

QRS complex

onset of ventricular depolarization

T wave

ventricular repolarization (relaxation), occurs just before the ventricles start to relax, shaped indicates slow process

arteries

strong elastic vessels, adapted for carrying blood away from the heart under high pressure

3 layers (tunicae)

outer (elastic), middle (smooth muscle), inner (endothelium/simple squamous)

veins

low pressure, contain 60-70% of the blood, smooth muscle causes blood flow through veins

hemodynamics

physiology of circulation

blood pressure

force against the inner walls of blood vessels

factors that influence BP

heart action, cardiac output, blood volume, peripheral resistance, elasticity of arteries

heart action

dependent on stroke volume and heart rate

cardiac output

volume of blood pumped by each ventricle each minute

blood volume

sum of formed elements and plasma

peripheral resistance

friction between blood and walls of blood vessels

elasticity of arteries

reduced elasticity may lead to increased blood pressure and reduced blood flow

frank-starling law of the heart

the more blood that enters the heart, the stronger the ventricular contraction, the greater the SV, and the greater the cardiac output

neural regulation

in medulla, chemoreceptors detect changes in blood chemical concentrations, and baroreceptors detect changes in BP in aorta and carotid arteries

when BP increases

parasympathetic impulses to slow the HR are sent

when BP decreases

sympathetic impulses to increase HR are sent