8 - Cardiovascular System Flashcards
what is the function of the circulatory system?
- transport essential materials throughout the body to cells where they are needed and to collect cell products generated by metabolic activity
what are the two sections of the circulatory system?
pulmonary circuit
systemic circuit
def: circuit that consists of blood vessels going to and from the lungs
pulmonary circuit
def: circuit that consists of blood vessels going to and from the rest of the tissues of the body
systemic circuit
def: the two upper chambers of the heart
atria
def: the two lower chambers of the heart
ventricles
what divides the left and right sides of the heart
the septum
which circuit does the right ventricle pump blood through
the pulmonary circuit
which circuit does the left ventricle pump blood through?
the systemic circuit
def: valve is damages or does not close properly so blood regurgitates causing a noise
heart murmur
what is the name of the heart muscle
myocardium
unlike skeletal muscle, all of the fibers or cells in cardiac muscle are anatomically interconnected, which is called…?
functional syncytium
the fibers of the atria are _______ ______ from the fibers of the ventricles
electrically separate
what is the pathway of the wave of depolarization across the heart?
- S-A node
- Atrial muscle fibers
- Contraction of atria
- Internodal Pathway
- A-V node
- A-V bundle
- Left and right bundle branches
- Purkinjie fibers travel throughout the ventricles
- Simultaneous contraction of the left and right ventricles
how long is the wave of depolarization delayed for in the A-V node and why?
0.10 seconds in order to give the atria time to contract and empty their contents into the ventricles
def: record the wave of depolarization as it passes across the heart using electrodes on the surface of the body
electrocardiography
ECG
what are the 3 components of a normal ECG waveform?
P wave
QRS wave
T wave
what does the P wave represent?
atrial depolarization
what does the QRS wave represent?
ventricular depolarization
what does the T wave represent?
ventricular repolarization
def: an irregularity in the rhythm of the heartbeat
arrythmia
how do you diagnose an arrythmia?
- look at heart rate
- amplitude and shapes of the ECG
- time intervals
what are three examples of arrythmias?
atrial
nodal
ventricular
condition where individual has irregularly high heart rate at rest
tachycardia (atrial fibrilation)
describe nodal arrythmia
second and third degree heart blocks (electrical conduction issus)
describe ventricular arrhythmia
premature ventricual contraction, ventricular tachycardia, ventricular fibrilation
what are the two major arteries that supply blood to the heart?
- left coronary artery
- right coronary artery
at rest, normal blood flow to the myocardium is about __% of the total cardiac output
4%
what increases cardiac output?
exercise
how much oxygen is extracted from blood flowing in the coronary vessels?
70-80%
def: blood vessels that carry blood away from the heart
arteries
what happens to arteries as they get smaller
there is less elastic tissue in the walls and more smooth muscle
def: arteries under 0.5 mm in diameter
arterioles
what do arterioles do during exercise?
they dilate, direction blood flow to the active muscles where oxygen and fuel for contraction is required
def: very tiny, thin walled vessels where exchange of nutrients and gases between the blood and tissues occurs
capillaries
def: small vessels which conduct venous blood from capillaries to veins
venules
def: vessels that convey blood toward the heart, greater diameter but thinner walled
veins
T or F: Veins can change their diameter
True
arteries and arterioles constitute the ____ pressure part of the circulatory system
high
the venules and veins constitute the ___ pressure part of the circulatory system
low
def: found in those veins which carry blood against the force of gravity, especially in the veins of the legs
valves
what are the 3 mechanisms involved in return of blood to the heart?
- pressure difference between the left ventricle and right atrium
- skeletal muscle pump, active muscles squeeze the veins and push blood to heart
- respiratory pump - decreased pressure in the thoracic cavity during inspiration
what are the types of cells in blood?
- red blood cells
- white blood cells
- platelets
- plasma
what percent of the body mass is blood?
8%
blood volume is greater for…?
larger, endurance, and altitude
what is plasma composed of?
90% water and 10% solutes
def: the ratio of the volume of blood cells to the total volume of blood cells to the total volume of blood expressed as a percentage
hematocrit
where do RBC’s form?
in the red bone marrow in ends of long bones and flat bones
what is the lifespan of an RBC
120 days
what are two sites of gas exchange in the body?
- alveolar capillary membrane in lung
2. tissue capillary membrane in tissues
what kind of diffusion occurs at the alveolar capillary membrane in lung?
- net diffusion of O2 from alveoli –> blood
- net diffusion of CO2 from blood –> alveoli
what kind of diffusion occurs at the tissue capillary membrane in tissues?
- net diffusion of O2 from blood –> tissue
- net diffusion of CO2 from tissue –> blood
what is the partial pressure of a gas dependent on?
- the total barometric pressure
2. the fractional concentration of the gas
what is the most important factor determining gas exchange?
the partial pressure gradients of the gases involved
the functional residual capacity serves as a damper so that each incoming breath of air only has a small effect of the composition of the _______ air
alveolar
def: the amount of gas that dissolves in a fluid is a function of two factors
1. pressure of the gas above the fluid
2. solubility coefficient of the gas
henry’s law
def: the volume of oxygen that crosses the alveolar capillary membrane per minute per millimeter mercury pressure between the alveolar air and pulmonary capillary blood
diffusing capacity for oxygen
what can affect diffusing capacity?
- the thickness of the respiratory membrane
- the number of red blood cells or their hemoglobin concentration
- the surface area of the respiratory membrane available for diffusion
how can diffusing capacity increase?
- during exercise more alveoli are ventilated
- opening up more capillaries in the lung and greater volume of blood flowing through the lung due to an increase in cardiac output
__% of the oxygen in the blood is carried in red blood cells in chemical combination with hemoglobin
98%
