cardiovascular Flashcards
functions of the cardiovascular system
Transport substances like oxygen and nutrients to cells
Transport metabolic wastes from cells and organs
Transport hormones, WBC, clotting proteins
Homeostasis (thermoregulation) (pH, hormones etc)
explain the flow of blood through the heart
Deoxygenated blood enters the right atrium through the vena cava, then it enters the pulmonary valve which then transports blood to the lungs.
At the lungs the oxygen undergoes gas exchange, it becomes oxygen rich.
The blood then travels around the body in veins, it then return to the left atrium, then into the left ventricle, then it travels out into the pulmonary veins, around the bodies.
what is ECG
Electrocardiogram (ECG) a visual display of the electricity polarisation in the heart.
describe the two hear sounds and what happens
First heart sounds (soft dubb as the AV valves close simultaneously)
Second heart sounds (louder dubb as the semilunar valves close simultaneously)
describe the artery and their function
tubular structure, very thick arterial walls that carry the blood away from the heart. They have thick smooth muscles, then endothelial layers internally. There are then arterioles, they are smaller arteries that lead into the capillaries that aid in blood regulation levels.
describe the vein and their function
carries deoxygenated back to the heart. They have thinner walls than arteries, not the vena cava is the largest vein and venules are smaller branches of arteries that connect to the capillaries. Note that they have venous valves, they are surrounded by skeletal muscle that contract to move the blood, the valves close if the blood moves in the wrong direction.
describe the capillary and their function
exchange the blood oxygenated and deoxygenated, they are a network that connect to both veins and arteries, they are the site of exchange plasma and interstitial fluid.) they hold no muscular walls, they do have pore that allow for passive movement.
what is cardiac output
Cardiac output is the amount of blood the heart pushes outward in a minute (stroke volume x heart rate)
define heart rate
Heart rate is the number of beats per minute.
define stroke volume
Stroke volume - the amount of blood that the heart outputs in a single beat. (end diastolic volume - end systolic volume)
define venous return
Venous return is determined by the muscles contraction (increased by exercise)
the blood theat return to the heart
Sympathetic innervation
increase contractility of the ventricle, increasing the stroke volume.
what are the two impacts on stroke volume
venous return
sympathetic innervation
what is the symathetic nervous sytem influence on heart rate
increase the heart rate by stimulating the SA node by pumping adrenaline which controls the B - adrenoceptors, these receptors speed the SA node, increasing heart rate. this is largley due to the thoracic and cervical nerves (accelatory centre)
what is the parasympathetic system influence on heart rate
decrease the heart rate. The heart muscle cells have ion channels. When potassium is pumped in the heart slows as the SA node reacts. This is largley connected to the vagus nerve
define blood pressure
force exerted on the walls measured in mmHg (millimetres of mercury) arteries have the highest and vein the lowest. Blood pressure is pulsatile, it changes depending on the phase of the heart cycle
Define diastolic pressure
where is minimum pressure is (80)
define systolic pressure
where the maxim pressure is (120)
define pulse pressure
the difference between the diastolic and systolic pressure
define mean arteial pressure
average blood pressure over several heart beats.
define baroreceptor reflex
Baroreceptors are pressure sensory receptors that respond by either stretching the arteries or contracting. They are located in the aortic arch and the carotid sinus.
what are the two mechanism of autoregulaton of blood flow
metabolic and myogenic
deifne myogenic mechanisim of blood flow
contraction of the vascular smooth muscle decreases the friction that the blood undergoes and increases the blood flow.
define metabloic mechanisim of blood flow
supply and demand, when needed to the blood vessels will increase blood flow of nutrients towards a tissue. This is situational (consider injury).
what are the regulatory pressure of mean arterial pressure (MAP)
There are short term regulation (heart and blood vessels, chemical control) or long term regulation (kidneys, hormonal)
what are they two factors that influence the MAP
cardiac output
Total peripheral resistance.
- Diameter of the vessels
- Length of the vessels
- Smoothness of the vessels
- Viscosity of the blood
what is the name for the ‘heart strings’ and the mucles that move them
chordae tendeae and the palpitory mucles
what is the name of the valve that connects the right atrium and right ventricle, and why is it called that
tricuspid
tricuspid means three, as there are three segments tin the valve.
what is the name of the valve that connects the left atrium and left ventricle, and why is it called that
bicuspid (matrial)
bicuspid mean 2 as the vavle has two function segments
what is the pace maker of the heart
Sinoatrial node
what is the second electricle nod of the heart and what does it connect to that aids in eletrical conduction
Atrioventritular node, which is connected to bundle branchs that are around the ventricles.
what are the four phases of the cardiac cycle
- ventricular filling
- isovolumetric ventricular contraction
- ventriculare ejection
- isovolumetric ventricular relaxation
