Please enable JavaScript.

Coggle requires JavaScript to display documents.

Cardiovascular system (The cardiac cycle (steps: (Isovolumetric…

- - - - AV valves closed
      - SL valves closed
    - - AV valves closed
      - SL valves open
    - - AV valves closed
      - SL valves closed
    - - AV valves open
      - SL valves closed
    - - AV valves open
      - SL valves closed
- - - - end diastolic volume. This is the amount of blood that fills the ventricle before it contracts and is measured in milliliters per beat
      - end systolic volume. This is the amount of blood that remains in the ventricle after contraction and is also measured in mL/beat.
  - - - Frank Starling's Law
        
        greater the stretch of the ventricular muscle, the more powerful the contraction
        
        . This would increase preload which will also increase the next factor, contractility.
        
        force of heart contraction is directly proportional to the initial length of the muscle fiber
      - how much the ventricle stretches in order to contract more forcefully
      - During exercise the ventricle would be receiving more blood which stretches the cardiac muscle fibers making for a more forceful contraction
      - . So exercise would increase the stroke volume
    - - Calcium ions are needed for the contraction of cardiac muscle cells
      - if a person is low in calcium then their heartbeat would be irregular which would decrease the stroke volume.
      - amount that cardiac muscle fibers can shorten
    - - . Anything that would slow this down would increase the afterload
      - amount of force needed to eject blood from the ventricle up through the semilunar valve
- - - - the T wave depicts the repolarization of the ventricles.
    - - depicts the depolarization of the ventricles, requires a much larger electrical signal because of the larger size of the ventricular cardiac muscle
    - - depicts the depolarization of the atria, very small wave, only have to contract to move the last 20% of blood to the ventricle
- - - - right atrium sends about 80% of blood into the right ventricle
        
        atrium contracts sending the next 20% into right ventricle: the pressure in the ventricle builds up the tricuspid valve closes
        
        pulmonary SL valve opens sending blood into pulmonary trunk and then to right and left pulmonary arteries when pressues enough
        
        When pressure in the pulmonary trunk is higher than pressure in the right ventricle, it fills the cusps of the SL valve and they close
        
        blood then travels through the lungs giving off carbon dioxide and taking up oxygen
        
        oxygenated blood then enters the left atrium through the pulmonary veins
        
        1 more item...
- - - - Cardiac output
      - Compliance
        
        how much that vessel can expand
        
        good compliance of a vessel then it can withstand the constant surges in blood flow
      - Blood vessel length and diameter
        
        small diameter, the blood is in contact with more of the endothelium.
        
        increases the peripheral resistance and is why blood moves slower in a smaller diameter vessel
        
        veins have large diameters and capillaries have small diameters
        
        blood slows down going through capillaries so that gas and nutrient exchange can occur in the organs
        
        play the largest role in controlling the amount of blood that goes to an organ are the arterioles
      - Volume of blood
        
        average amount of blood volume in a person is about 6 L
        
        excessive bleeding or dehydration may cause a decrease in blood volume
      - Viscosity of the blood
        
        how thick a solution is that will affect its ability to flow
        
        difference in the plasma or the formed elements
    - - Sympathetic Nervous System
        
        Sympathetic nerve fibers release norepinephrine that binds to the smooth muscle of the arterioles
        
        stimulates the contraction of the muscle resulting in vasoconstriction
        
        arterioles only receive innervation by the sympathetic nervous system
        
        Vasodilation achieved by decreasing the sympathetic action
        
        arterioles are the blood vessels that control blood flow to organs
      - Baroreceptors
        
        cardiac inhibitory center in the medulla is also signaled which results in a decrease in heart rate
        
        Vasodilation is a result of this which leads to a decrease in blood pressure
        
        detect changes in arterial pressure, when stretched, they send an impulse to the cardiac center in the medulla oblongata
        
        stretch receptors that are found in the walls of the aorta and the carotid arteries
  - - - Edmea= too much fluid that collects in the interstitial space and the lymphatic capillaries can't remove that much
      - edematous= due to an excess of fluid accumulating in the interstitial space
      - lymphatic capillaries run next to blood capillaries so they take up the excess fluid and take it to the heart
      - blood is moving from an area of higher pressure at the arteriole end to an area of lower pressure on the venule side
      - two main pressures on the fluids inside and outside the capillary
        
        Osmotic pressure
        
        protein which is considered a colloid
        
        blood colloidal osmotic pressure: proteins are too big to cross the capillary walls
        
        comes from the side with the most solute as it pulls the water towards it in an order to equalize the concentrations of the two sides
        
        proteins in the interstitial space that may create osmotic pressure on the venous end of the capillary bed
        
        when there are two solutions of different solute concentrations that are separated by a semipermeable membrane
        
        create interstitial fluid osmotic pressure
        
        Hydrostatic pressure
        
        Capillary hydrostatic pressure (CHP) is the force that pushes water out of the blood into the interstitial space
        
        higher in the arterial end versus the venous end
        
        force of the fluid against the capillary wall
        
        also hydrostatic pressure from the interstitial space into the blood
        
        called the interstitial fluid hydrostatic pressure (IFHP).
        
        Net filtration pressure: difference between the net hydrostatic pressure and the osmotic pressure= regulate the movement into and out of the capillaries
        
        at arterial end, a positive net filtration pressure favors the movement of fluid from the blood into the interstitial cells.
        
        NFP (arterial) = Filtration - Absorption
        
        positive number= net movement of fluid is moving OUT of the capillary at the arterial end.
        
        at venous end: look at the net filtration pressure
        
        when blood has gotten to this end there is not much hydrostatic pressure in the blood as it is now far away from the heart and slowed down by the capillaries
        
        NFP (venous) = Filtration - Absorption
        
        negative number= net movement of fluid is moving into the capillary
- - - - Cardiac cells are autorhythmic: meaning contraction is not run by the nervous system but rather by its own rhythmic waves that originate from the pacemaker of the heart.
      - linked by gap junctions which allows action potentials to travel quickly and have the heart work as one unit.
      - much more dependent on voltage-gated calcium channels
      - similarities
        
        contain multiple myofibrils, sarcoplasmic reticulum and T-tubules
      - steps to cardiac contraction
        
        the nodes (AV and SA), and the pathway
        
        specialized cells in cardiac muscle that contain no contractile proteins (myosin, actin)
        
        capability of setting their own rhythm
        
        SA (sinoatrial) node is the primary pacemaker and is located in the upper right atrium
        
        sends a signal about 80 times per minute
        
        don't contract, send a spark that moves out across both atria and down to the secondary pacemaker, the AV (atrioventricular) node
        
        electrical impulse travels between the two nodes, is called the internodal pathway
        
        AV node is located at the bottom of the right atrium
        
        the signal travels to the AV bundle then down the septum dividing into right and left branches.
        
        From here ^^^ it spreads out to both atria and signals the ventricles
        
        SA node --> internodal pathway --> AV node ---> AV bundle --> bundle branches --> Purkinje fibers
      - refractory period is much longer in cardiac cells
      - uninucleate
    - - skeletal muscle cells must be stimulated by a motor unit of a neuron
      - multinucleate