Heart and Blood Flashcards
the circulatory system is?
a system of tubes with a pump and valves to ensure one-way flow of blood
why is it called double circulation?
blood passes through the heart twice for each complete circulation of the body
right side:
collects deoxygenated blood from the body and pumps it to the lungs under relatively low pressure
left side:
the oxygenated blood then returns from the lungs to the left side of the heart, where the pressure of the blood is raised in order to pump it to all organs of the body
advantages of a double circulation
- oxygenated is seperate from deoxygenated: septum ensures complete seperation
- the blood pressure in systemic circulation can be higher than that in the pulmonary circulation.
- the left ventricle has a thicker wall due to more muscle so it pumps blood under higher pressure to the organs. this means metabolites such as nutrients and oxygen can reach the tissues faster which will speed up all metabolic processes, enhancing heat generation or muscle movement.
- the right ventricle has a thinner wall to pump blood under a lower pressure to the lungs to avoid lung damage. is pulmonary pressure was equal to systemic, the tissues in the lungs would be damaged as tjey need to be very thin.
systemic
body
pulmonary
lungs
right side of heart
collects deoxygenated
left side of heart
pumps oxygenated to body
blood is pumped away from the heart into_______ and the blood returns in ________
arteries (a away)
veins
what are coronary arteries used for?
provide heart muscle with oxygen and glucose as cardiac muscle does not tire
the two upper chambers are called the ______. the two lower chambers are called the ______
atria (a above)
ventricles
the right atrium receives blood from the _______ ______. the left atrium receives blood from the ________ ________.
vena cava
pulmonary vein
what do the bicuspid and tricuspid valves fo?
prevent backflow of blood, ensuring blood flows only from the atria to the ventricles
the right ventricle pumps blood into the _____
the left ventricle pumps blood into the ________.
pulmonary artery
aorta
what do the semilunar valves do?
they allow blood to move upwards into the arteries from the ventricles but prevent blood from flowing in the opposite direction
why is the blood in the aorta under higher pressure than in the pulmonary artery?
the wall of the LV is much thicker than the RV as it needs to pump blood around the body. so the blood in the aorta is under higher pressure as it carries blood under high pressure around the body
heart: to and from
to heart: vena cava and pulmonary vein
from heart: pulmonary artery and aorta
lungs: to and from
to lungs: pulmonary artery
from lungs: pulmonary veins
kidneys to and from
to kidney: renal artery
from kidney: renal vein
describe coronary heart disease
- coronary arteries supply blood containing glucose and oxygen to the heart muscles
- if a coronary artery gets blocked the cardiac muscle runs short of oxygen
- this blockage is called CHD
- the cardiac muscle cannot respire—> no energy to contract and pump blood
- the heart stops beating: heart attack/cardiac arrest
cause of CHD: poor diet with too much saturated fat
- saturated fat can be converted into cholesterol which builds up in the arteries.
- individuals with hereditary high levels of blood cholesterol are more prone to developing CHD
cause of CHD: smoking
- nicotine damages the heart by reducing the elasticity of blood vessels
stress:
stress causes and increase of blood pressure: can result in fatty materials depositing in arteries
genetic predisposition:
DNA determines the size of the arteries, so characteristics of the heart are passed onto the offspring
age CHD
the risk of coronary heart disease increases with age. about 80% of people who die of CHD are 65 or above
gender:
mainly affects men of 45/55
women during menopause rarely suffer as the hormone oestrogen protects them
explain the effect of physical activity on the heart rate
- during exercise muscle cells must contract so they require more energy. so they need more glucose and oxygen per minute.
- the heart rate must increase to provide cells with more glucose and oxygen and to remove tje co2 produced during exercise
normal heart rate is about 70 beats a minute
the rate becomes lower the fitter you are
artery structure
- thick tough wall with muscles and elastic tissue // to withstand and maintain blood pressure (prevents bursting)
- narrow lumen // maintains high blood pressure
- valves absent /// none needed as high pressure prevents backflow of blood
vein structure
- thin wall with less muscles and elastic tissue// allows muscles to exert pressure on the veins
- wide lumen // allows great volume of blood to pass and reduces resistance to blood flow
valves present // prevent backflow of blood
capillary structure
permeable wall (one cell thick) no muscle or elastic tissue // allows diffusion of materials between capillary and surrounding tissue.
pores in the wall allow white blood cells to exit
luman approximately one red blood cell wide // narrow lumen allows blood cells to pass thru slowly and increases oxygen diffusion from red blood
cell
red blood cells function
red due to haemoglobin which binds to oxygen so the red blood cell can transport oxygen to the tissues
white blood cell function
fight infection vy phagocytosis and antibody production
platelets
cause blood clotting
plasma
transport of blood cells, ions, soluble nutrients, hormones and carbon dioxide.
NC BISH
antibody production:
- all cells have proteins on their surface called antigens
- lymphocytes recognize foreign antigens on foreign cells (such as bacteria) and make antibodies against them
- a different antibody is used for each antigen
- some antibodies make bacteria clump together in preparation for action by phagocytosis
tissue rejection:
- transplants involve replacing a damaged organ with a donor organ
- however lymphocytes detect the foreign antigens of the donor organ and make antibodies to it
- the donor organ is rejected as antibodies fight the foreign tissue
- the donor organ needs to be from similar tissue (3‘e.g from a relative)
- immunosuppressive drugs are user, which switch off the bodys immune response - however the drawback of these drugs are that the patient needs to be kept in isolation as they are at the risk of dying from any diseases they are exposed to.
phagocytosis
phagocytes have the ability to move out of capillaries to the site of infection
they then engulf and ingest the infecting pathogens and kill them by digesting them
features of alveoli
- large surface are so that a lot of gas particles can be exchanged at one time
- they are in contact with a dense network of capillaries for quick exchange of gases
- thin wall —> short diffusion distance
- well ventilated —> high diffusion gradients are maintained for gas exchange
role of goblet cells, mucus, ciliated cells
goblet cells produce a sticky substance called mucus which traps pathogens and particles in the inhaled air
the ciliated cells then waft this mucus with the trapped pathogens and particles upwards to the throat where it is then swallowed
smoking can cause
chronic obstructive pulmonary disease COPD
CHD
lung cancerw
nicotine
a small chemical which diffuses across the alveoli into the blood in the blood plasma to all parts or the body
it causes narrowing if the coronary arteries, increases blood pressure, addiction
carbon monoxide
this is a gas which diffuses across the alveoli into the blood in the capillaries. it binds to haemoglobin in the red blood cells and therefore reduces the amount of oxygem which the RBC can transport. therefore the body cells receive less oxygen so they cannot respire normally, leading to tiredness.
tar
goblet cells produce a abnormally thick mucus. it also paralyses the cilia so mucus trickles down into the alveoli causing a lung infection and breathing problems
it also leads to coughing which damages the alveoli thus interfering with gas exchange
