The Cardiovascular system consists of what?
Consists of the heart and a closed system of vessels (arteries, capillaries, and veins) through which the blood circulates
When does the heart begin to beat regularly?
The heart begins to beat regularly early in the fourth week after fertilization.
This system reaches a functional state long before any other major organ system.
Fibrous Pericardium
tough, loose-fitting, and inelastic sac around the heart well-lubricated and provides protection against friction
Serous Pericardium
consists of 2 layers: the parietal and visceral layers.
Parietal layer
lining inside of the fibrous pericardium
Visceral layer (epicardium)
adheres to the outside of the heart; between visceral and parietal layers is a space (pericardial space) which contains a small amount of pericardial fluid (lubricating fluid secreted by the serous membrane).
What three layers make up the heart wall?
The epicardium, myocardium, and endocardium
Epicardium
actually the visceral layer of the serous pericardium
Myocardium
bulk of the heart wall; thick, contractile, specially constructed and arranged cardiac muscle cells
Endocardium
interior lining; delicate endothelial tissue (Endothelium tissue lines the heart and vessels)
Septum
- divides the heart lengthwise into two sides
Atrium
upper chamber of each side of heart (pl. atria)
Ventricle
lower chamber of each side of heart
The right side of the heart pumps blood to where?
the lungs
The left side of the heart pumps blood to where?
the body
Valves
one way valves control the flow of blood between atria and ventricles, as well as from the ventricles to the lungs and the rest of the body
Atrioventricular
one way valves between atria and ventricles (a-v valve); a cord-like muscle prevents them from reversing when ventricles contract
Semilunar
one way valves between ventricles and pulmonary artery and aorta
Atrioventricular Bundle
(AV bundle or Bundle of His) - special cardiac muscle fibers originating in AV node and extending by two branches down sides of interventricular septum; generates impulse from AV node to apex
Purkinje Fibers
continuation of AV bundle fibers to lateral walls of ventricles; allow ventricles to contract at paced intervals
How long does an entire cyce of a heartbeat take?
8/10th of a second
Systole
-phase of heartbeat in which ventricles are contracted (highest pressure
Diastole
phase of heartbeat in which ventricles relaxe; blood flowing in from atria (lowest pressure)
what happens during the lubb?
shutting of tri- and bicuspid valves (ventricles contracted and force these atrioventricular valves closed)
what is happening during her dup?
shutting of semi-lunar valves (blood in the arteries forces them closed)
what happens during the 'rest' of a heartbeat?
ventricles are refilled with blood
What is the average heartbeat for men and women?
Average resting heart rate for men is around 70 bpm and for women it is around 75 bpm.
Tachycardia?
resting heart rate is around 100 bpm
Bradycardia
esting heart rate is less than 60 bpm
What is the average blood presure?
120/80 mm Hg
Sphygmomanometer
instrument used to measure blood pressure in terms of how many millimeters high the air pressure raises a column of Hg in a glass tube
A sphygomanometer is placed over which artery?
Brachial Artery
Korotkoff sounds
the different sounds produced when the blood begins to flow through the artery again.
What is the normal blood pressure? What can high blood pressure cause? How can you decrease blood pressure?
Considered normal if under 140/90
Any pressure over this is considered high blood pressure and may increase your chances of a stroke or heart attack.
Decrease blood pressure by maintaining a healthy weight, decreasing salt intake, not smoking, or by takin
what is fibrillation?
Condition in which the heart flutters uncontrollably
Disrupts the flow of blood, reducing the amount that flows through the heart
Why does the flow of blood require a systematic beat of the heart?
push blood into the proper chambers at the proper time.
What are the two subsytems of circulation?
Pulmonary and systemic
Pulmonary
blood between heart and lungs
Pulmonary artery is the only one carrying what?
Deoxygenated blood
oxygenated blood
Pulmonary veins are the only ones to carry what?
oxygenated blood
capillaries release CO2 and absorb O2 where?
the lungs
Systemic
blood between heart and all other body tissues
the Systemic system can be further divided into what?
renal, heptic portal, and coronary.
Portal system
venous blood flows through a second capillary network before returning to the heart (gateway)
Veins from where do not send blood directly to the inferior vena cava?
Veins from the spleen, stomach, pancreas, gallbladder, and intestines
blood is sent through the hepatic portal to where?
the liver.
The liver removes excess glucose to store as glycogen (only moderate glucose sent to heart); detoxifies or removes toxic molecules such as alcohol before blood is sent to the heart.
Blood flowing through the heart does not what?
nourish the heart tissue.
What are the coronary arteries?
two small vessels that branch off the aorta at its very beginning; the openings lie behind flaps of the aortic semilunar valve.
Order of Blood Vessels
Heart - Aorta - Smaller Arteries - Arterioles - Capillaries - Venules - Veins - Inferior & Superior Vena Cavae - Heart
Arteries
Carry blood away from heart
Except for the pulmonary artery, they carry oxygenated blood
Strong and elastic with a thicker muscular wall than veins
Do not have valves because there is sufficient pressure to move blood through
Capillaries
Regarded as most important blood vessels
Fine lattice-work of microscopic tubes
Walls are one cell layer thick
Allow for diffusion of gases and nutrients
Red blood cells must travel through in single file
Veins
Carry blood toward the heart
Except for the pulmonary vein, they carry deoxygenated blood
Thinner and less muscular than arteries because blood is under less pressure
Some contain valves to prevent backflow
Rely on movement of skeletal muscles to squeeze
Ischemia
reduced flow of blood to tissue resulting in impairment of cell function
Myocardial Infarction
Heart Attack" = Death of heart muscle cells in the myocardium
Blockage in coronary arteries can cause ischemia, which can then lead to cell death
Heart can continue to function if only a small amount of tissue is damaged
Rheumatic Heart Disease
Inflammatory response to an improperly treated streptococcal infection
Occurs most often in children
Cardiac valves and other tissues in body may become inflamed (rheumatic fever) which can result in stenosis (narrowing of blood vessel) or other deformiti
Heart Murmur
When the cusps of the valves close, they should form a seal. If anything interferes with the fit, blood "leaks."
This "leaking" blood can be heard as a murmur.
Diseases such as rheumatic fever produce an inflammatory reaction resulting in scarring, shorte
Mitral Valve Prolapse
Condition affecting the mitral valve; can be genetic or caused by rheumatic fever or other factors
The flaps extend back into the left atrium and cause the valve to "leak"
Common - occurring in 1 out of 20 people
Usually causes no problems, but can result
Cardiomyopathy
Disease of the myocardial tissue in which it becomes inflamed
May reduce pumping effectiveness
Three main types:
Dilated (congestive) - heart cavity enlarged and stretched
Hypertrophic - muscle mass of the left ventricle enlarges or "hypertrophies"
Restri
Atherosclerosis
Partial arterial blockage due to build up of plaque, which may be due to the deposition of fats and other substances in the wall of the artery.
Aneurysm
Section of artery that has become abnormally widened due to weakening in arterial wall
Can be dangerous because:
They promote the formation of thrombi (abnormal clots)
They have a tendency to burst, causing severe hemorrhaging that could lead to death
Bra
Varicose Veins
Enlarged veins in which blood pools; may bulge and cause venous valves to leak.
Congenital Heart Disease
Heart disease in infants that involves arrhythmia and malfunction of heart muscles
Heart is usually not completely developed in infants with this
Can involve problems with valves, septum, or even holes in the heart
Hypertension
A.K.A. = High Blood Pressure
Known as the "Silent killer" because doesn't always show signs (headaches, dizziness, fainting)
Force of blood exerted by the arterial blood vessel exceeds 140/90 mm Hg.
Potential complications if untreated:
Heart failure
Kidn
Angina
Pressure and/or pain in the chest due to insufficient blood supply to the heart
Not an actual disease, but a symptom of any number of diseases
May be a sign of coronary artery disease (coronary arteries supply blood to the heart itself)