The Heart And Circulatory System Flashcards
Define Plasma
an aqueous solution of proteins, ions, nutrient molecules and gas but mostly water
Define erythrocytes(rbc)
Are the oxygen carriers of the blood
Define Leukocytes(wbc)
-provide the body’s front line of defense against disease
Define Platelets
-induce blood clots that seal breaks in the circulatory system
Bone marrow has multipotent stem cells that give rise to:
-Myeloid stem cells and lymphoid stem cells
What type of cells come from myeloid stem cells
-erythrocyte, platelets, monocyte/macrophage, eosinophil, basophil, neutrophil
What type of cells come from lymphoid stem cells
Natural killer cell, T lymphocyte, B lymphocyte
What are the three plasma proteins
-Albumins
-globulins
-fibrinogen
What plasma protein is responsible for osmotic balance, pH, transport, hormones, waste, and drugs
-Albumins
What plasma protein is responsible for transport of lipids, fat soluble vitamins
-Globulins (ex. immunoglobulin)
What plasma protein is responsible for blood clotting
-Fibrinogen
What are the plasma ions
-Na+, K+, Ca2+, Cl-, HCO3-
What are the functions of erythrocytes
Contain hemoglobin (transports oxygen to lungs), flexible can squeeze through capillaries
What are the functions of Leukocytes
Defend body against infecting pathogens, eliminate dead and dying cells
What are the functions of platelets
-cell fragments enclosed in plasma membrane, triggers clotting
What are the four chambers of the heart
-Two atria at the top of the heart
-Two ventricles at the bottom of the heart
-Atrioventricular (AV) valves between atria and ventricles
-Semilunar (SL) valves between ventricles and aorta/ pulmonary arteries
What are the two separate circuits the blood is pumped into
-Pulmonary circuit
-Systemic circuit
What are the systole and diastole in the basic heart beat
-Systole: ventricle contracting
-Diastole: ventricle relaxing, chambers filling, atria relaxing
Pulmonary artery pumps
-deoxgenated blood in the lungs
Pulmonary vein pumps
oxygenated blood into the heart
Systole-diastole sequence is the
-cardiac cycle
Systolic pressure
-contraction of ventricles pushes blood into arteries at peak pressure
Diastolic pressure
-between ventricular contractions, blood pressure in arteries falls to a minimum pressure
Define afterload
systemic vascular resistance, is the amount of resistance the heart must overcome to open the aortic semilunar valve and push the blood volume out into the systemic circulation
Define preload
-left ventricular end diastolic pressure is the amount of ventricular stretch at the end of diastole. The heart is loading up for the next big squeeze of the ventricles during systole
What are the steps of the cardiac cycle
-heart is fully relaxed; atria begins to fill with blood; AV and SL valves are closed
-blood fills atria and pushes AV valves open; ventricles begin to fill
-atria contract, filling ventricles completely
-ventricles begin to contract, forcing AV valves closed; SL valves remain closed
-Ventricles contract fully, forcing SL valves open and ejecting blood into arteries
Define stroke volume
-the amount of blood ejected per beat from left ventricle and measured in mL/beat
-Stroke volume increases proportionally with exercise intensity
SV= EDV-ESV
-stroke volume equals end diastolic volume(volume of blood in ventricle after filling phase)- end systolic volume(blood left in the ventricle after contraction)
Define cardiac output
the amount of blood pumped by the heart in 1 minute measures in L/min
-if either heart rate or stroke volume increase or both, cardiac out increases also
What is the main idea of stroke volume-force of contraction
-Amount of blood pumped out is proportional to how much blood returns to the heart
-As more blood comes back to the heart, the blood that is coming back stretches the heart muscle to a great extent than normal
If more blood comes back…
the heart muscle is stretched more and the volume leaving per beat is increased
What other two things can effect the force of contraction?
-Sympathetic and parasympathetic activity
How does the parasympathetic nerve stimulation effect the heart rate
-it decreases the heart rate
What do parasympathetic neurons produce
-the neurotransmitter, Acetylcholine
How does acetylcholine effect the heart rate
-ACh binds to ligand gated channels on the cardiac cell membrane which causes K+ to go out which hyperpolarizes the cell. The hyperpolarized membrane take longer to depolarize and causes and action potential
-the heart rate decreases
How do M2 muscarinic receptors effect the heart rate?
-they act to slow the heart rate down to normal sinus rhythm after stimulatory actions of the sympathetic nervous system, by slowing the speed of depolarization
Where are the sympathetic nerves located that send signals to the heart?
-The thoracic region of spinal cord project to the heart as cardiac nerves
Sympathetic nerves innervate the….
-SA and AV nodes
-the coronary vessels
-the atrial and ventricular myocardium (heart muscle)
Does sympathetic stimulation increase or decrease heart rate and force of muscular contraction?
-increase
Sensory neurons carry action potentials from… Chemoreceptors in the medulla oblongata influence the…
-baroreceptors to the cardioregulatory center.
-cardioregulatory center
The cardioregulatory center controls…
-the frequency of action potentials in the sympathetic and parasympathetic neurons
Parasympathetic neurons extend to the
-heart through the vagus nerves
Sympathetic neurons extend through…
-the adrenal medulla