Cardiac System Flashcards
what is the circulatory system responsible for?
the internal transport of substances to and from the cells
what are the 3 parts of the circulatory system?
- blood
- blood vessels
- heart
what is blood composed of?
water, solutes, and other elements in a fluid connective tissue
blood vessels
tubules of diff. sizes that transport blood
heart
muscular pump that provides the pressure necessary to keep blood flowing
closed circulatory system
the heart and blood vessels are continually connected (most animals have this)
how is the flow of blood in capillary beds?
slow
lymph vascular system
cleans up excess fluids and proteins and returns them to the circulatory system
what 3 layers do the walls of all blood vessels consist of?
- what is the exception to this?
tunica intima (innermost layer), tunica media (made up of smooth muscle cells and elastic fibers), and tunica adventitia (outermost layer)
- capillaries
what is the structure of elastic arteries?
- function?
includes aorta and major branches, tunica media qhas more elastin than any other vessels, largest vessels in the arterial system
- stretch when blood is forced out of the heart, recoil under low pressure
what is the structure of muscular arteries?
- function?
includes the arteries that branch off the elastic arteries, tunica media has a higher proportion of smooth muscle cells and fewer elastic fibers as compared to elastic arteries
- regulate blood flow by vasoconstriction/ vasodilation
what is the structure of arterioles?
- function?
tiny vessels that lead to the capillary beds, tunica media is thin but composed almost entirely of smooth muscle cells
- primary vessels involved in vasoconstriction/ vasodilation, control blood flow to capillaries
what is the structure of arterioles?
- function?
tiny vessels that lead to the capillary beds, tunica media is thin but composed almost entirely of smooth muscle cells
- primary vessels involved in vasoconstriction/ vasodilation, control blood flow to capillaries
what is the structure of venules?
- function?
tiny vessels that exit the capillary beds, thin porous walls, few muscle cells and elastic fibers
- empty blood into larger veins
what is the structure of veins?
- function?
thin tunica media and tunica intima, wide lumen, valves prevent backflow of blood
- carry blood back to the heart
how much blood does an adult human have?
5 quarts
what is blood made up of?
red and white blood cells, platelets, plasma
what percentage of blood does plasma take up?
- what is plasma?
over 50%
- made up of mostly water and serves as a solvent. contains plasma proteins, ions, glucose amino acids, hormones, dissolved gases
what do red blood cells do?
- where are they formed?
- what should be known about red blood cell count?
transport oxygen to cells
- bone marrow
- they are constantly being replaced by fresh ones which keeps the total number stable
what do white blood cells do?
- what are the 5 types?
defend the body against infection and remove waste
- lymphocytes, neutrophils, monocytes, eosinophils, basophils
platelets
fragments of stem cells that serve an important function in blood clotting
how many chambers does the heart have?
4
what does each half of the heart contain?
- what are these halves separated by?
an atrium and a ventricle
- AV valve, located between the ventricle and the artery leading away from the heart
what do valves do?
keep blood moving in a single direction and prevent backwash into the chambers
the heart has its own _____ with its own _____
circulatory system; coronary arteries
atrial contraction
- ventricular contraction
- what is this sequence called?
fills the ventricles
- empties ventricles
- cardiac cycle
what are self exciting muscles?
muscles that do not need external stimuli since the electrical system of the heart controls the heartbeat as cardiac muscle cells produce and conduct electrical signals
what 2 phases does the cardiac cycle consist of?
- what can these 2 phases be further divided into?
- do these events occur together?
diastole and systole phases
- first and second phases to describe events of the right and left sides of the heart
- yes
SA node
- where is it located?
pacemaker of the heart
- located in the wall of the right atrium
what happens during the first diastole phase?
- blood flows through the superior and inferior venae cavae
- the heart is relaxed, so blood flows from the atrium through the open AV valve to the right ventricle
- the SA node generates electrical signals which are carried by purkinjie fibers to the rest of the atrium
- atrium is stimulated to contract and fills the right ventricle with blood
- the impulse from the SA node is transmitted to the ventricle through the AV node
- AV node signals the right ventricle to contract, which initiates the first systole phase
what is the AV valve AKA?
tricuspid valve
what happens during the first systole phase?
after the impulse from the SA node is transmitted to the ventricle through the AV node (this happens in the first diastole phase):
1. tricuspid valve (AV valve) closes
2. pulmonary semilunar valve opens
3. blood is pumped out the pulmonary arteries to the lungs
what happens during the second diastole phase?
after blood is pumped out of the pulmonary arteries to the lungs (this happens in the first systole phase):
1. blood returning from the lungs fills the left atrium
2. the SA node triggers the mitral valve to open and blood fills the left ventricle
3. mitral valve closes and the aortic semilunar valve opens
4. left ventricle contracts, blood is pumped out of the aorta to the rest of the body
what are the 3 types of circulation?
- coronary
- pulmonary
- systemic
coronary circulation
- how does it work?
flow of blood to the heart tissue
1. blood enters the coronary arteries (which branch off the aorta), supplying major arteries which enter the heart with oxygenated blood
2. the deoxygenated blood returns to the right atrium via cardiac veins which empty into the coronary sinus
pulmonary circulation
- how does it work?
the flow of blood between the heart and lungs
1. deoxygenated blood flows from the right ventricle to the lungs through pulmonary arteries
2. oxygenated blood flows back to the left atrium through the pulmonary veins
systemic circulation
- how does it work?
the flow of blood to the entire body (with the exception of pulmonary and coronary circulation)
1. blood exits the left ventricle of the aorta which branches off into the carotid arteries, subclavian arteries, common iliac arteries, and the renal artery
2. blood returns to the heart through the jugular veins, subclavian veins, common iliac veins, and renal veins, which empty into the superior and inferior vena cavae
what 2 other types of circulation are included in systemic circulation?
- portal
- renal
portal circulation
the flow of blood from the digestive system to the liver and then to the heart
renal circulation
the flow of blood between the heart and the kidneys
arterial blood pressure
functions by transporting oxygen-poor blood into the lungs and oxygen-rich blood to the body tissues
arteries
branch into smaller arterioles which contract and expand based on signals from the body
arterioles
where adjustments in the blood are made in blood delivery to specific areas based on complex communication from the body systems
capillary beds
diffusion sites for exchanges between blood and interstitial fluid
capillary
has the thinnest wall of any blood vessel, consists of a single layer of endothelial cells
capillaries merge into ____ which then merge with ____
venules; veins
veins
- what facilitates what veins do?
- describe the walls of veins and their function
transport blood from body tissues back to the heart
- valves inside veins
- thin and contain smooth muscle, function as blood volume reserves
