Cardiovascular (circulatory) system Flashcards
what is the function of the circulatory system?
transport
what is the main transport medium of the circulatory system?
blood
list the 3 components of the circulatory system
blood, arteries, veins
describe the heart
cone-shaped, hollow muscular structure
what is the base of the heart?
where the heart attaches to other structures
what is the apex of the heart?
the free side of the heart, the point of the cone
which side of the heart sits more cranially and which is more caudal?
the right side is more cranial, the left side is more caudal
what does the heart sit within? how many layers does that thing have?
a protective layer called the pericardium, which has two layers
list and describe the 2 layers of the pericardium including their tissue types
- parietal pericardium: outer layer, dense irregular connective tissue
- visceral pericardium: inner layer, fused to muscle of heart, thin layer of simple squamous epithelium
what is the pericardial space? what is it filled with and what is its function?
the space between the parietal and visceral pericardium, filled with pericardial fluid, reduces friction
how many layers does the heart wall have? list them
3
outer layer, myocardium, inner layer
describe the outer layer of the heart wall, including 2 alternate names and the tissue type
also called epicardium, is the same thing as the visceral pericardium, simple squamous epithelium
describe the myocardium layer of the heart wall, including tissue type and describe thickness
middle layer, thickest, made of cardiac muscle tissue, thicker on left side than right side
describe the inner layer of the heart wall, including an alternate name and tissue type
also called endocardium, simple squamous epithelium
list and describe the 2 types of heart chambers
Atria: (L & R), receive blood from veins
Ventricles: pump blood into arteries
list and describe the 2 broad types of heart valves
Atrioventricular valves: separate atria from ventricles
Semilunar valves: separate ventricles from arteries
list and give the location of the 2 types of atrioventricular valves
- tricuspid valve: separates right atrium from right ventricle
- mitral (bicuspid) valve: separates left atrium from left ventricle
list and give the location of the 2 types of semilunar valves
- pulmonary valve: separates right ventricle from pulmonary artery
- aortic valve: separates left ventricle from aorta
what is the ventricular septum?
a layer of myocardium that separates the left and right ventricles
describe the path of blood flow through the heart, beginning with the right atrium
deO2 blood flows from the right atrium through the tricuspid valve into the right ventricle, then through the pulmonary valve, out the pulmonary artery to the lungs, where gas exchange occurs. O2 blood flows back in through the pulmonary vein into the left atrium, through the mitral valve into the left ventricle, then through the aortic valve out the aorta to the body, where O2 is delivered. DeO2 blood then flows in through the vena cavae (superior, or cranial, and inferior, or caudal) back into the right atrium
where are the largest blood vessels located?
by the heart
list the flow of blood vessels from largest to smallest and back to largest
heart –> arteries –> arterioles –> capillaries (smallest) –> venules –> veins —> heart
what can fit through a capillary?
only one line of cells at a time, very tiny
list the 2 main circulatory systems
- pulmonary circulation
2. systemic circulation
describe pulmonary circulation
transports deoxygenated blood from the heart to the lungs, and oxygenated blood from the lungs to the heart
describe systemic circulation
transports oxygenated blood from the heart to the body (except the lungs) and deoxygenated blood from the body to the heart
what is coronary circulation?
the vascular system of the heart
what do portal systems do? how?
depart from normal circulation, a vein reforms a capillary bed in another tissue before returning blood to the heart
describe cardiac muscle cells
mono-/di- nucleated, striated, with the sarcomere as the basic contractile unit, have intercalated disks that connect the cells
describe cardiac muscle cells as they relate to contraction of the heart
the intercalated disks that connect them allow for transfer of the action potential between cells, where every individual cell no longer needs the stimulus to contract, instead the stimulus can be passed along through the disks
list the 8 steps of transmission of an action potential throughout the heart
- pacemaker cells in the sinoatrial (SA) node in the right atrium simultaneously generate action potentials
- action potential will spread throughout atria due to intercalated disks
- atria contract
- atrioventricular (AV) node in right atrium transmits action potential to bundle of His (in center of heart)
- bundle of His branches off into right and left bundle branches which transmit the action potential down the ventricular septum and around ventricles
- right and left bundle branches branch out into Purkinjie fibers, which transmit the action potential to cardiac muscle cells of ventricles
- action potential spreads across ventricles via intercalated disks
- ventricles contract
what is the cardiac cycle?
the sequence of events that occur during one complete heart beat
list and describe the 2 steps of the cardiac cycle
- diastole: relaxation of ventricles, atria are contracting and pushing blood through AV valves into ventricles
- systole: contraction of ventricles, blood is being pushed through semilunar valves into arteries, atria are relaxed and filling with blood from vena cavae or pulmonary vein
which step of the cardiac cycle is the “lub” sound?
systole
which step of the cardiac cycle is the “dub” sound?
diastole
describe heart rate
frequency of cardiac cycles in one minute, measured in beats per minute (bpm)
what determines heart rate (2)
animal body size, corresponds with life expectancy
what is blood pressure?
the force applied to artery walls, measured in (systolic/diastolic) systolic should be a bigger number
