The Heart & Blood
The Heart Coronary Heart Disease(CHD)
Problem with arteries and blood supply to heart
Pacemaker - the heart has a pacemaker, your → damages heart muscles because not enough
resting heartbeat is controlled by a group of cells blood
in the right atrium reaches the heart = lack of oxygen
The cells produce a small electric impulse
which spreads around the muscle cells causing Causes of this are: high blood pressure, smoking,
them to contract alcohol, obesity, ageing, family history
Cholesterol builds up in the arteries blocking blood flow
Artificial pacemakers - used to control heartbeat if
natural pacemaker cells don’t work LDL - brings cholesterol to be deposited on artery
properly(patient have irregular heartbeat) walls
- Is a device implanted under the skin HDL - takes cholesterol to liver from arteries to be
- has a wire going to the heart burned
- produces electric current to keep heart
beating regularly Stents - wire mesh inserted inside arteries, keep open
so blood can pass through to keep heart beating
Tissue - a group of similar cells that work together + lower risk of heart attacks
to perform a particular function + effective long time
Organ - a group of different tissues that work Dis
together to perform a certain function - risk of complications in surgery
Organ system - a group of organs working - risk of infection
together to perform a particular function - risk of patient developing blood clots near stent
Causes of high cholesterol in blood - diet & Statins - reduce the amount of cholesterol in
genes blood stream, decrease rate of fatty deposits
→ slows rate of fatty deposits forming in the
Blood is a tissue coronary arteries
Negatives
Coronary arteries - supply blood to the heart - muscle pains & damage, liver damage
, Alveoli - increased blood sugar - diabetes
- Thin walls, gases can diffuse through easily Plasma - mainly liquid, 55% of blood, carries dissolved
- Large surface area to allow diffusion to substances(nutrients, CO2, waste products,
happen at a faster rate hormones, salts etc)
- Good blood supply to maintain
concentration gradient Red blood cells - no nucleus so can carry more
haemoglobin,
bi concave & flexible to travel narrow blood vessels
large surface area exposing them to more oxygen
White blood cells - deal with infections, ingest
microorganisms that enter body, produce
antibodies and produce antitoxins to kill bacteria
Lymphocytes - produce antibodies, these are
chemicals that kill pathogens or stick to them so
phagocytes can ingest them
Phagocytes - collect at site of infection and ingest
pathogens
Breathing - allows oxygen to enter the lungs and
pass into the alveoli to diffuse into the blood, Platelets - triggers blood clotting, binds together with
breathing keeps O2 levels high in the alveoli, fibrous, prevents blood loss & microorganisms
maintaining the concentration gradient entering blood, are fragments of cells
Diaphragm moves out → volumes increases → Trachea transports air, spits into bronchi then alveoli
pressure decreases → air sucked in
Heart transplants
Artificial hearts - not usually used as permanent fixes
- Used to keep patient alive while waiting for a
donor
- Allows people to recover allowing heart to heal
and rest
Donor hearts - heart that is from a donor, human
Adv
- no mechanical parts that wear out
- blood flows more smoothly
Dis
- donors are hard to find
Arteries - carry blood to body, oxygenated, high
- more likely for heart to be rejected by immune
pressure
system
Veins - deoxygenated blood, carries blood to heart, → have to take drugs for the rest of their lives to
low pressure, valves prevent backflow, wider
prevent this, drugs lead to increased risk of infection
lumen to help blood flow
Capillaries - brings blood to cells, substances
diffuse in & out blood, 1 cell thin walls for diffusion,
Rate of blood flow = Volume of blood
blood from arteries to veins, found in organs &
Number of minutes
tissues, under pressure, substances squeezed out
into intracellular space, permeable walls
Heart
