MCAT Biology - The Cardiovascular System

Right side of heart

accepts deoxygenated blood returning from the body and moves it to the lungs by the way of pulmonary artieries

Left side of the heart

Recieves oxygenated blood from lungs by way of pulmonary veins and forces it out fo the body through the aorta

Atria

Thin walled structures where blood is recieved from either the vena cava or pulmonary veins

Atrioventricular valves

Separate the atria

Semilunar valves

Separates ventricles from vasculature

Tricuspid valve

Valve between right atrium and right ventricle

Bicuspid Valve

Valve between left atrium and left ventricle

Pulmonary valve

Spearates right ventricle from pulmonary circulation

Aortic valve

Separates left ventricle from aorta

Order of electrical conduction in heart

SA node → AV node → bundle of his → purkinje fibers

SA Node

where impulse initiation occurs and generates 60-100 signals per minuete

AV node

delays signal to allow ventricles to fill copmletely before they contract

Purkinje fibers

distribute electrical signal thrugh the ventricular muscle

Intercalated discs

Connect muscle cells

Systole

ventricular contraction and closure of AV valves occur and blood is pumped out of the ventricles

Diastole

ventricles are relaxed, semilunar valves are closed, blood from atria fills the centricels

Cardiac output

Total blood volume pumped by a ventricle in a minuete

Hepatic Portal System

Blood leaving capillaries in walls of gut passes through hepatic portal vein before reaching capillary beds in the liver

Hypophyseal portal system

Blood leaving capillary beds in the hypothalamus travels to a capillary bed in the anterior pituitary to allow pancrine secretion of releasing hormones

Renal Portal System

blood leaving glomerus travels through efferent arteriole before surrounding nephron in capilarry network

Arteries

Travels blood away from the heart

Veins

thin walled, inelastic vessels that transport blood to the heart

endothelial cells

maintain the vessel by releasing chemicals that aid in vasodilation and vasoconstriction

capillaries

small vessels with a single endothelial layer that allow diffusion of gases nutrients and wastes

venules

smaller venous structures that connect capillaries to the larger veins of the body

Plasma

liquid portion of blood, an aqueous mixture of nutrients salts respiratory gases, hormones and blood proteins

How much of blood is plasma

55%

How much of blood is erthrocytes

45%

How much of blood is leukocytes

<1%

Erythrocyte

Specialized cell designed for oxygen transport

Hemoglobin

Bind four molecules of oxygen, each RBC has about 1 billion molecules of oxygen

Bioconcave

indented on both sides

Benefits of RBC shape

Assists in travel through capillaries, increaes surface area increasing gas exchange

Normal hemoglobin in male

13.5-17.5 g/dL

Normal Hemoglobin in female

12-16 g/dL

Normal Hematocrit Male

M (41-53%)

Normal Hematocrit Female

36-46%

Thrombocytes

cell fragments or shards released from cell in bone marrow

Hematopoiesis

Production of blood cells and platelets triggered by hormones, growth factors, cytokinesis

erythropoieten

Secreted by kidney and stimulates mainly red blood cell development

Thrombopoietin

secreted by liver and kidney, stimulates mainly platelet development

granulocytes

contain cytoplasmic granules that are visible microscopy

A granulocytes

do not contain granules

lymphocytes

important in specific immune response

Specific immune response

body’s targeted fight against pathogens

B cells

responsible for antibody generation

T cells

kill virally infected cells and activate other immune cells

Monocytes

Phagocytize foreign matter

Macrophages

Monocytes leave blood stream and enter an organ

Microglia

nervous system

Langerhan Cells

Skin

Osteoclast

bone

Antigen

any specific target to which the immune system can reach

ABO antigen

A and B alleles are codominant a person might express one, both or none of the ABO antigens

O blood

considered universal donors because blood will not cause ABO related hemolysis in any recipent

AB blood

universal recipents because they can recieve blood from all types, no blood antigen foreign to those have it

Rh factor

surface protein expressed red blood cells refer absense or presnse of specific allele one positive allele is enough protein be expressed

erythroblastosis fetalist

pregnant fetus immune system make antibodies against it, maternal anti Rh antiobdies cross placenta and attack fetal blood, resulting in hemolysis

Blood Pressure

a measure of the force per unit area exerted on the wall of blood vessels

Sphygmonmanometer

measures blood pressure

Hemoglobin

Protein composed of four cooperative subunits, each of which has prosthetic hemogroup binds to an oxygen molecule

Oxygen saturation

% of hemoglobin molecules carrying oxygen

Cooperative binding

allosteric regulation process for xoygen and hemoglobin

Atrial natriuretic peptide

hormone aids with loss of salt within nephron acting as a diruetic with loss of fluid

Cooperative binding

allosteric regulation process for oxygen and hemoglobin

Bohr effect

hemoglobin decreased affinity for oxygen, shifting the oxyhemoglobin curve the the right

Hydrostatic Pressure

force per unit area the the blood exerts against the vessel walls

Osmotic pressure

sucking pressure generated by solutes as they attempt to draw water in blood stream

Starling forces

the balance of opposing pressures that is essential for maintaining the proper fluid volume and solute concentration inside and outside vasculature

clots

composed cogulation factor and platelets and prevent blood loss