Week 4 - The Cardiovascular System Flashcards
what is homeostasis?
maintaining a relatively constant internal environment in the face of a constantly changing external environment
what is the core concept in physiology?
homeostasis
what are examples of physiological variables?
body temp, blood composition, heart rate, red blooc cell concentration
what causes variation in physiological state?
sex, age, fasted/fed and exercise/red
how is homeostasis regulated?
nervous and endocrine system
what is the nervous system vs endocrine system?
nervous - transmits signals along dedicated pathways within seconds
endocine - signalling via hormones over long time and long-lasting
where are hormones transported?
blood
how many types of blood vessels are there?
5
what are the names of the 2 cardiovascular loops?
pulmonary and systemic circulation
what way is a heart depicted on paper?
the left side of the heart is depicted on the right, (it is the persons left)
which chamber of the heart is thicker and why?
left side (on right side of diagram) because it is pumping blood out of the heart
what percentage of our total body weight does the blood make up?
8%
average blood volume in the body?
5 litres in women, 5.5 in men
what are leukocytes?
white blood cells
what makes up the most of blood?
55% plasma
what makes up 45% of blood?
erthyrocytes - red blood cells
what blood vessels emerge from ventricles?
arteries
what blood vessels emerge from atria?
veins
in what order is blood pumped out of the ventricles?
ventricle, artery, arteriole, capillary, venule, vein, atrium
what benefit is smooth muscle to blood vessels?
contraction and relaxation - allow change of diameter
what is it called when a blood vessel contracts?
vasoconstriction
what happens when a blood vessel contracts?
blood vessels narrow, blood pressure increases
what is it called when a blood vessel relaxes?
vasodilation
what happens when a blood vessel relaxes?
more blood can flow through, blood pressure decreases
give an example of vasdilation
when temperature increases, blood vessels widen and during exercise
give an example of vasconstriction
when temperature drops
where does blood go following systemic circulation?
it goes into right atrium, then ventricle, contraction pushes blood out of pulmonary artery
where does blood go following pulmonary circulation
it has been oxygenated in the lungs and enters left atrium and then ventricle, contraction forces blood out of aorta beginning systemic circulation
what causes contraction in the heart?
electrical currents
the heart is autorhythmic, what does this mean?
it will still beat without nerve connections
how does the heart generate its own pulse?
pacemaker cells in SA node
where is SA node?
right atrium
describe electrical current and blood flow in heart:
blood enters atria, SA node initiates contraction and blood enters ventricles, purkinje fibres initiate contraction of blood out of heart through artery
what is it called when heart chambers contract?
systole
what is it called when heart chambers relax?
diastole
how long is cardiac cycle?
0.8 seconds
what is the heart rate when cardiac cyle is 0.8sec long?
60/0.8 = 75bpm
describe the flow of blood
unidirectional
what does the lup dup heart sound come from?
valves opening and closing
in an ECG what does P wave represent?
artial excitation/ systole
in an ECG what does QRS complex represent?
ventricular excitation/ systole
in ECG what does T wave represent?
Resting state return
what does ECG allow?
testing for cardiac abnormalities
why is the body a good conductor of electricity?
blood is full of electrodes
