Cardiovascular System Flashcards
organs involved in the cardiovascular system
heart, blood vessels, blood
cardiovascular system
closed system of the heart and blood vessels
- the heart pumps blood
- blood vessels allow blood to circulate to all parts of the body
deliver oxygen and nutrients and remove carbon dioxide and other waste products
facts about the heart
- located in thorax between the lungs, slightly toward the left lung, apex towards left hip
- about the size of your fist and less than 1 lb
three types of blood vessels
arteries (and aterioles), capillaries, veins (and venules)
arteries
- carry blood away from the heart
- constrict or dilate, changing blood pressure
- middle layer of the artery wall consists of smooth muscle that can constrict to regulate blood flow and blood pressure
artery layers
- tunica intima (tunica interna)
- tunica media
- tunica externa (tunica adventitia)
tunica intima (tunica interna)
simple squamous epithelium surrounded by a connective tissue basement membrane with elastic fibers
tunica media
- primarily smooth muscle and usually the thickest layer
- provides support for the vessel and changes vessel diameter to regulate blood flow and pressure
tunica externa (tunica adventitia)
- attaches the vessel to the surrounding tissue
- connective tissue with varying amounts of elastic and collagenous fibers
capillaries
- have walls
- only one thick cell to allow exchange of games and nutrients with tissue fluid
- capillary beds are present in all regions of the body
- contraction of the sphincter muscle closes off a bed
- blood can flow through the arteriovenous shunt that bypasses the capillary bed
veins
- carry blood to the heart
- blood passes through the capillaries, enters through the smallest veins called venules
- veins have much less smooth muscle and connective tissue than arteries
- have valves that prevent the backward flow of blood when closed
- carry about 70% of the body’s blood and act as a reservoir during hemorrhage
heart
- cone-shaped muscular organ located between the lungs and behind the sternum
- heart muscle forms the myocardium, with tightly interconnect cells of cardiac muscle tissue
- the pericardium is the outer membrane sac with lubricating fluid
4 chambers of the heart
two upper, thin walled: Right and Left Atria
two lower, thick walled: Right and Left Ventricles
septum
a wall dividing the right and left sides of the heart
atrioventricular valves
- tricuspid valve on right
- bicuspid/mitral valve on left
what are the tricuspid/bicuspid valves supported by
chordae tendineae
passage of blood flow
- Superior and Inferior Vena Cava
- Deoxygenated Blood fills Right Atrium
- Through Tricuspid Valve into Right Ventricle
- Through Pulmonary Valve into Main Pulmonary Artery
- Into Lungs
- Into Pulmonary Veins
- Into Left Atrium
- Through Bicsupid Valve into Left Ventricle
- Through Aortic Valve into Aorta
- Out into the body
high blood pressure
also called hypertension, caused when the force of blood pushing against the artery walls is too high and the heart has to work harder to pump blood
normal blood pressure
Lower than 120/80 mmHg
elevated blood pressure
top ranges from 120 to 129 mmHg
bottom is below 80 mmHg
stage 1 hypertension
top is 130 to 139 mmHg
bottom is 80 to 89 mmHg
stage 2 hypertension
top is 140 mmHg or higher
bottom is 90 mmHg or higher
damage to arteries
- high blood pressure can damage cells of the artery
- when fats from food enter the bloodstream, they can collect in arteries
- artery walls become less elastic, limits blood flow throughout the body
damage to heart
- high blood pressure strains heart
- over time, this can cause the heart muscle to weaken or become stiff and not work as well as it should
- hypertensive heart slowly started to fail
pulmonary circulation
movement of blood to and from the lungs for gas exchange
- deoxygenated blood is transported from the right side of the heart through the blood vessels to the lungs
- oxygenated blood is transported through the blood vessels to the left side of the heart
- movement of blood from the right side of the heart, to the lungs, to the left side of the heart
systemic circulation
movement of blood to and from cells
- oxygenated blood is transported from the left side of the heart through the blood vessels to the systemic cells such as liver cells, muscle cells, and brain cells
- deoxygenated blood is transported through blood vessels that return blood to the right side of the heart
- systemic circulation is the movement of blood from the left side of the heart, to the cells of the body, back to the right side of the heart
layers of heart
- external epicardium
- myocardium
- endocardium
external epicardium
- outermost layer of heart, also called “visceral layer of serous pericardium”
- composed of thin, flat layer of cells and underlying layer of loose connective tissue
- thickens as we age as it becomes surrounded by adipose connective tissue
myocardium
- middle layer
- cardiac muscle tissue and is the thickest if the three layers
- may change in thickness as we age or if we participate in regular, rigorous exercises
endocardium
- internal surface of heart, external surface of heart valves
- thin, flat layer of cells and underlying layer of loose connective tissue
heart conduction system
network of nodes, cells, and signals that control the heartbeat
- do not contract, rather initiate and conduct electric signals
conduction system’s 4 structures
- sinoatrial (SA) node: posterior wall of right atrium, adjacent to superior vena cava, initiate heartbeat, “pacemaker of the heart”
- atrioventricular (AV) node: floor of right atrium, between right AV valve and opening for the coronary sinus (largest vein of heart)
- atrioventricular (AV) bundle: “Bundle of His”, extends from AV node into and through the interventricular septum, divides into left and right bundles
- purkinje fibers: extend from left and right bundles, beginning the apex of heart and continue through walls of ventricles
ECG recording
electrical changes within the heart that are detected during routine physical examination using monitoring electrodes attached to the skin (usually at wrists, ankles, and 6 locations on chest)
electrical signals are collected and chated as a electrocardiogram, ECG, EKG
ECG waves and segments
P wave: above baseline
QRS complex: Q and S with small downward deflections and R with large defection above
T wave: above baseline
P wave
electrical changes of atrial depolarization generated with SA node
approx 0.08 to 0.1 second
QRS complex
electrical changes associated with ventricular depolarization
approx 0.06 and 0.1 second
T wave
electrical changes associated with ventricular repolarization
cardiac cycle
change within the heart from the beginning of one heartbeat to the start of the next
systole
contraction of a heart chamber
diastole
relaxation of heart chamber
alternating pressure changes are responsible for what two significant physiological processes
- unidirectional movement of blood through heart chambers, as blood moves along a pressure gradient
- opening and closing of heart valves to ensure blood moves without backflow
ventricular contraction
ventricles contract and ventricular pressure rises
one way flow of blood occurs as AV valves are closed and semifinal valves are open, allowing ejection of blood into pulmonary artery from right ventricle and the aorta from the left ventricle
ventricular relaxation
ventricles relax and their pressure decreases
semilunar valves close, AV valves open, allowing blood to flow from each atrium into its corresponding ventricle
cardiac output
- amount of blood pumped by a single ventricle in 1 min (Lpm)
- determined by heart rate and stroke volume
heart rate
of beats per minute (bpm)
stroke volume
volume of blood ejected during one beat (milliliters per beat)
blood
connective tissue made of cellular elements and an extracellular matrix
- cellular elements: formed elements such as red blood cells, white blood cells, and cell fragments called platelets
- extracellular matrix: plasma, make blood unique among connective tissues because it is fluid
function of blood
- deliver oxygen and nutrients to body cells and remove wastes
- defense, distribution of heat, maintenance of the homeostasis
- maintain chemical balances
- proteins and other compounds act a buffers to help regulate pH of body tissues
- helps regulate water content of body cells
characteristics of blood
oxygenated: bright red
deoxygenated: duskier red
- hemoglobin is a pigment that changes color depending on degree of oxygen saturation
blood viscosity
5 times greater than water
- viscosity is a measurement of a fluids thickness or resistance to flow and is influenced by the presence of the plasma proteins and formed elements within the blood
- dramatic impact to blood pressure and flow
pH of blood
averages 7.4
7.35 to 7.45 in healthy person
blood transportation
transports formed elements and dissolved molecules and ions
transports oxygen from and carbon dioxide to the lungs
delivers medication
blood color
oxygen rich: bright/scarlet red
oxygen poor: dark red
- bluish appearance of vein can be attributed to 1. the fact we can see the blood moving through the superficial veins and 2. how light is reflected back to the eye from different colors
what composes blood
erythrocytes, leukocytes, platelets, and plasma
erythrocytes
red blood cells, takes up oxygen in lungs and releases into tissue
leukocytes
white blood cells, defending body against pathogens
platelets/thrombocytes
irregular shaped, dark central region and help clot the blood, prevent blood loss from damaged cells
plasma
fluid portion of blood containing plasma proteins and dissolved solutes
molecules of the plasma membrane of an erythrocyte
surface antigens
2 groups of surface antigens that determine blood type
ABO blood group and Rh Factor
ABO blood group
two surface antigens/glycoproteins : A and B
- type A: erythrocytes with surface antigen A
- type B: erythrocytes with surface antigen B
- type AB: erythrocytes with surface antigen A and B
- type O: erythrocytes with neither surface antigen A or B
ABO surface antigens are accompanied by?
specific antibodies in blood plasma
- antibody is Y shaped protein that binds to a specific antigen that is recognized as foreign in the body
antibodies and blood types
- Type A has anti-B
- Type B has anti-A
- Type AB has neither
- Type O has both
8 blood types
A positive (A+,A-,O+,O-), A negative (A-,O-), B positive (B+,B-,O+,O-), B negative (B-,O-), AB positive (universal recipient), AB negative (A-,B-,O-,AB-), O positive (O+,O-), O negative (universal donor, O-)
Rh Factor
determined by presence or absence of the Rh surface antigen (Rh Factor or Anti-D)
- Rh Factor present: Rh+ (never exhibit anti-D antibodies because they possess Rh antigen on erythrocytes)
-Rh Factor absent: Rh- (can exhibit anti-D antibodies, can only occur after exposure to Rh antigens)
hemostasis
- stoppage of bleeding
- three phases: vascular spasm, platelet plug formation, coagulation phase
vascular spasm
- damage to smooth muscle within the vessel causing smooth muscle contraction
- results in vasoconstriction and limits blood that can leak from the vessel
- last from a few to many minutes, more extensive, the great the degree of vasoconstriction
platelet plug formation
- collagen fibers become visible
- platelets stick to exposed collagen fibers with assistance of a plasma protein
- platelets are involved in all 3 phases
coagulation phase
- most important and complex
- initiation of blood clotting can occur by 2 mechanisms: intrinsic pathway and extrinsic pathway
intrinsic pathway
triggered by damage to inside of vessel wall and is initiated by platelets, typically takes 3 to 6 minutes
extrinsic pathway
initiated by damage to the tissue that is outside the vessel, take approx. 15 seconds
blood smear
- all components of formed elements can be viewed like this
- test that examines the size, shape, and number of cells in blood sample
- thin layer if blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically
