The heart Flashcards
give two features of cardiac muscle
myogenic- can contract and relax without nervous or hormone stimulation
never fatigues- as long as it has O2 and glucose
what happens if the cardiac muscles run out of O2
respire anaerobically- produce lactic acid= heart attacks!!
how can blocked coronary arteries cause heart attacks
blocked means they cannot carry oxygenated blood to cardiac muscle
cardiac muscle receive no O2
they respire anaerobically- produce lactic acid- heart attack
why does the right ventricle have a thinner wall than the left ventricle
RV pumps blood to lungs, LV pumps blood to whole body= to lungs is shorter distance
blood from RV flowing at lower pressure- prevents damage to capillaries in lungs
lower pressure so moving slower- allows more time for gas exchange
what is the only vein that carries oxygenated blood
pulmonary vein
from LUNGS to LA
what is the only artery that carries DEoxygenated blood
pulmonary artery
from RV to LUNGS
when do AV valves:
- open
- close
- open when pressure is greater BEHIND
- close when pressure is greater IN FRONT
describe the function of the septum
seperates deoxygenated and oxygenated blood
maintains high O2 concentration in oxygenated blood
maintains concentration gradient- enables diffusion at respiring cells
why is there a delay between atrial systole and ventricular systole?
all the blood needs to leave the atrium and enter ventricle
atrium walls recoil to push all blood into the ventricle
when do semi lunar valves:
- open
- close
open when pressure is greater in ventricles
close when pressure is greater in artery
what is meant by correlation
a relationship between variables
what is meant by causation
when one variable has an influence on another variable
describe the effects of smoking on blood
- nicotine- stimulates adrenaline- raises blood pressure and heart rate - damage to artery walls and fatty deposit build ups
- carbon monoxide- binds to Hb- reduces capacity of Hb to carry O2
describe the influence of blood cholesterol on the heart
high density lipoproteins= low conc cholesterol :)
low density lipoproteins= high conc cholesterol- fatty deposit build up
describe the effect of diet on heart
- high salt increases blood pressure- damage to artery walls
- lots of saturated fats- low density lipoproteins- higher conc blood cholesterol- fatty deposit build up
function of:
- muscle layer
- elastic layer
- thin endothelium
- muscle layer- constricts and dilates to control volume of blood flowing
- elastic layer- stretches and recoils- maintains blood pressure
- thin endothelium- allows diffusion
why is the muscle layer in arterioles relatively thicker than arteries
needs to constrict to narrow the lumen as arterioles carry blood into the capillaries- need to reduce blood flow
why is elastic layer in arterioles relatively thinner than arteries
carrying blood at lower pressure than arteries
describe 3 features of capillary structure and how they relate to function
- thin outer wall- endothelial layer 1 cell thick- SHORT diffusion distance
- lots of capillaries, and highly branched- HIGH SA
- narrow diameter- no cell is far from capillary- SHORT diffusion distance
- narrow lumen- red blood cells flattened against capillary wall- SHORT diffusion distance
- spaces between endothelial cells- allow white blood cells to escape and deal with infections
why do capillaries have fibrous tissue around them
to prevent cells and and proteins from leaking out
list the 2 routes by which tissue fluid returns to bloodstream
via lymphatic system
via capillaries
state what forces tissue fluid out of blood plasma in capillaries and into surrounding tissues
hydrostatic pressure due to pumping of the heart
how are the contents of the lymphatic system moved
- hydrostatic pressure of tissue fluid that has left the capillaries
- contraction of body muscles which squeezes the lymph vessels
