circulatory Flashcards
what is the blood comprised of?
55% plasma and 45% cells(rbc, wbc, platelets)
what is the function of blood?
transport oxygen to cells, maintain homeostasis, arrest haemorrhage through clotting and defend against disease
what is the function of rbc
aka. erythrocytes and they function to transport oxygen to cells from the lungs and take up CO2 from cells and transport it back to the lungs
what are characteristics of rbcs
erythrocytes; have no nucleus, few organelles, are disc-shaped and contain hemoglobin. they circulate for 120 days then are broken down in the spleen(hemolysis).
what are immature rbcs called
reticulocytes
what is the ratio of rbcs to blood?
5 million rbc per mL of blood.
what is the function of wbcs?
defend against disease; fight bacterial infection and remove foreign material
what are wbcs called
leukocytes
what is the function of platelets
play a role in clotting blood, play a role in wound healing and maintain homeostasis(by preventing blood loss)
what are platelets called
thrombocytes
what are some characteristics of platelets?
no nucleus, contain granules of clotting factors and other substances. they are not whole cells, but pieces of megakaryocyte cells.
characteristic of wbcs
contain a nucleus.
what is the composition of plasma
water(90%), protein(8%), mineral salts, nutrients, cellular waste products, hormones, enzymes, antibodies, dissolved gases(O,N CO2)
describe process of blood clotting
- damaged endothelium
- temporary plug formed by platelets; which release thromboplastin
- thromboplastin converts prothrombin to thrombin
- thrombin converts fibrinogen to fibrin
- fibrin traps wbcs and rbcs
what is blood clotting called
coagulation
what mineral does prothrombin need to convert to thrombin?
calcium
describe pathway of blood
Deoxygenated blood enters through inferior or superior vc, into right atrium, where it is pumped through tricuspid valve to right ventricle, where it is pumped through pulmonary valve to pulmonary artery, which pumps the deoxygenated blood to the lungs, where it is oxygenated. It comes back through pulmonary veins into left atrium, its pumped through mitral valve, into left ventricle, then through aortic valve, into aorta, where it is pumped to the rest of the body.
describe sequence of events in cardiac cycle
- Atrial systole(atria contact together)
- Ventricular systole(ventricles contract together)
- diastole(all 4 chambers at rest)
*lasts for 0.8 s and resting HR is usually 72 bpm
describe electrical conduction system of heart
Parasympathetic nerves control HR set by SA node(aka. Pace maker)
Resting HR is 72-75 bpm.
Sympathetic nerves innervate SA node, AV node and myocardium(muscular layer)
This increases hr and contractility of ventricles, especially left ventricle.
what is normal systolic bp
80-120 mm Hg
what is normal diastolic bp
60-80 m Hg
what is ‘normal’ level of pressure on vessels in adults?
120/80 mmHg
what are arteries?
carry blood away
what are veins?
carry blood to heart
what are venules
very small veins
what are arterioles
very small arteries
what is capillary
smallest vessels; they link arterioles and venules; and Has intimate contact with tissues.
where does internal respiration occur?
in capillaries
what is lumen
cavity inside an anatomical structure
what are the 3 layers of an artery
- tunica intima(innermost; endothelial layer of squamous epithelial cells
- tunica media(smooth muscle and elastin)
- tunica adventitia- collagen
what do veins have that artieries dont?
valves
why do veins have valves?
to prevent backflow
what is internal respiration
exchange of oxygena dn carbon dioxide at cellular level; occurs b/w capillaries and tissues
larger vessels have more______tissue and less____ tissue
have more elastic tissue and less muscle tissue
what does hepatic artery do?
(off aorta) carries blood to liver
what is systemic circulation
b/w body and heart
pulmonary circulation
b/w heart and lungs
coronary circulation
blood circulation in heart
arteries for coronary circulation are?
left and right coronary arteries
arteries/veins for blood circulation to head
left/right external jugular veins
left/ right common carotid arteries
left internal jugular vein
portal/hepatic circulation is?
doesnt follow direct route to heart, goes to spleen, stomach, liver and so on
portal veins do what? for what circulation system?
bring deoxygenated blood through liver from spleen, intestines and stomach
blood exits the liver via____?
hepatic vein
what does hepatic vein
allow blood to exit liver to go to vena cavas.
what is coronary heart disease
narrowing and hardening of coronary arteries due to athetosclerosis(build up of plaque on artery walls) , can result in heart attack
what is heart attack aka
myocardial infarction
what are the risk factors of coronary heart disease?
inheritance, overweight, high blood cholesterol, lack of exercise, smoking, high BP, long-term stress
deoxygenated blood come in what side of the heart?
right
oxygenated blood comes in what side of the heart>
left
heart is seperated by ..
septum
blood vessel that collects blood from digestive organs?
hepatic portal vein
70 bpm
is average heart rate
