Circulatory System Flashcards
Stroke volume
- The volume of blood pumped from one ventricle of the heart in a single pump (healthy individuals have the same stroke volume for both ventricles)
- SV = EDV - ESV
- EDV = volume of blood in ventricle before contraction
- ESV - volume of blood in the ventricle at the end of the contraction
Activated thrombin converts:
Fibrinogen to fibrin
What does the Q wave of electrocardiogram represent?
Depolarization through the interventricular septum (which initiates ventricular depolarization)
What are known as capacitance vessels?
Veins because of their high capacity —> most of the body’s blood is found in veins
Pulmonary circulation:
Moves deoxygenated blood to the lungs in order to become oxygenated
The pathway is as follows:
Superior/inferior vena cava —> right atrium —> tricuspid valve —> right ventricle —> pulmonary semilunar valve —> pulmonary arteries —> lungs —> pulmonary veins —> left atrium
Which blood do cardiac veins carry?
Deoxygenated blood from the myocardium
What does thromboplastin convert?
Prothrombin (inactive precursor) to thrombin (active form)
Automaticity
A property of all cardiomyocytes, allowing cardiomyocytes to have the ability to generate action potentials without external nerves having to initiate the action potential
Cardiac output
- volume of blood being pumped by the heart (ventricle) in one minute
CO = HR x SV
What do activated platelets release?
Thromboplastin (also called a tissue factor)
How to calculate mean arterial pressure
MAP = CO x TPR
Cardiac output from the heart multiplied by the total peripheral resistance of the vessels
What is another name for the respiratory pump?
Abdominothoracic pump because it involves both the abdomen and the thoracic cavity
Hemolymph
Functions as both blood and interstitial fluid in organisms that contain an open circulatory system
It contains nutrients (similar to blood) and lies between cells (similar to interstitial fluid)
Sinuses
- found in organisms with open circulatory systems (arthropods)
- Small, open-ended chambers that hemolymph move into form the dorsal vessel
Hemocoel
A large cavity (body cavity) that surrounds all of the internal organs of the insect where sinuses empty hemolymph into
It allows for the hemolymph to surround and nourish all of the organs
Ostia
Openings in the tubular hearts in which hemolymph can re-enter the relaxed heart and go back to the dorsal blood vessels
It does so by locomotion and muscular contractions
Spiracles
Tiny holes that allow air to pass into the tracheal tubes/system (act as nostrils)
Tracheal system
(Act as lungs) Responsible for gas exchange between the insects cells (the hemolymph) and the environment
Which circulation has a higher resistance to blood flow?
Systemic circulation
Coronary circulation
Circulation in which the heart pumps blood to itself
Which part of the heart received oxygen-rich blood from the coronary arteries?
Coronary arteries branch off the aorta and provide oxygen-rich blood to the hearts myocardium (beginning of coronary circulation)
SA node
(Sinoatrial node)
Known as the pacemaker of the heart
Usually initiates the cardigan cycle
Has the greatest automaticity in the heart: most likely to reach the threshold and stimulate action potentials to ripple through the other heart cells (stimulating a heartbeat)
Sends signal to contract both atria to send blood to the ventricles
Sends signal to the AV nose to initiate contraction
Which nerve of the parasympathetic nervous system sends a signal to slow down the SA node?
The parasympathetic vagus nerve extends from the medulla oblongata and inner gates the SA node, the vagus nerve exerts a default signal to slow down the SA to a normal rate
Path of cardiac conduction:
1) SA node: reaches threshold and sends a wave of depolarization to both atria causing both of them to contract and send the blood to the ventricles
2) AV node: once the wave of depolarization reaches the bottom of the right atrium, it reaches the AV node which adds a brief delay between contraction of the atria and ventricles (this allows them to contract at different times so ventricles can completely fill)
3) Bundle of His: AV node sends an electrical signal to the bundle of His, located in the interventricular septum
4) Left and right bundles: Bundle of His sends an electrical signal to the left and right bundle branches
5) Purkinje fibers: the left and right branches pass the signal to the purkinjie fibers, located within the walls of the ventricles, allow for coordinated ventricular contraction
Systole
The phase of the cardiac cycle where blood pressure is highest in the arteries
When does systole occur during the cardiac cycle?
Right after the ventricles eject blood *into** their connecting arteries
Diastole
Phase of the cardiac cycle where blood pressure is lowest in the arteries, the myocardium is completely relaxed at this point
When does diastole occur during the cardiac cycle?
Right after the end of ventricular contraction
Lub
When both atrioventricular valves snap shut, causing the semilunar valves to open
The left and right atria are relaxed as the left and right ventricles are contracting
Dub
Semilunar valves snap shut
The left and right ventricles are relaxed as the left and right atria are contracting
Between which heart sounds does systole occur?
Lub & dub
Between which heart sounds does diastole occur?
Dub & lub
Intercalated discs
Contact points between adjacent cardiomyocytes that connect heart cells to each other
Allow for signal transduction
Made up of desmosomes and gap junctions
Desmosomes
Small proteins that adhere cardiomyocytes together
Act like “stitches”, stitching cardiomyocytes together
Gap junctions
Protein tunnels that connect cytoplasm of cardiomyocytes
Allow molecules and ions to directly pass from cell to cell and therefore propagating action potentials from one tell to the rest of the heart
Syncytium
Connect of many heart cells together, allowing for the coordination of heart function as a unified organ
Umbilical vein
Carries oxygenated blood from the placenta to the fetus via the umbilical cord
Ductus venosus
Connects the umbilical vein to the inferior vena cava
Allows oxygenated blood coming from the umbilical vein to flow into the inferior vena cava and mix with deoxygenated blood
Blood inside the inferior vena cava can then be slightly oxygenated
Foramen ovale
A hole in the fetal heart allowing for the slightly oxygenated blood to travel directly from the right atrium to the left atrium
Arterial end of the capillary
Forces plasma out of the vessel because hydrostatic pressure is high
This is how nutrients get dropped off to the tissues
Venous end of the capillary
Wastes are pulled back into the capillary due to oncontic pressure (a type of osmotic pressure)
At the venous end of the capillary, what causes wastes to be pulled into the capillary?
When there is a high protein content within the venous end, oncontic pressure increases causing water to flow back into the capillary along with the substances dissolved in it
Lymph nodes
An aggregate of lymphocytes (immune cells) that trigger immune response when they come across factors that must be eliminated and thus filters out harmful bacteria from lymph
What do cardiac veins and coronary arteries carry?
Cardiac veins: deoxygenated blood from the heart
Coronary arteries: oxygenated blood to the heart
What would occur if there were a decrease in plasma protein levels?
Is levels of plasma protein (e.g. albumin) decreased, the oncotic pressure in the blood vasculature would decrease as well, leading to less water returning to the blood and more water remaining in the interstitial fluid —> this leads to the increase in lymph volume
blood brain barrier
- blockade of cells
- prevents or slows the passage of drugs, ions and pathogens into the central nervous system
- it is permeable to oxygen, carbon dioxide, glucose and general anesthetics
hemorrhage
- excessive bleeding
- results in decrease in arterial pressure
- the decrease in pressure is sensed by arterial baroreceptors
- in order for the body to compensate for the reduced blood pressure, it increases the heart rate and system vascular resistance
- maintains pH of internal fluids of all cells
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