The heart Flashcards

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1
Q

give two features of cardiac muscle

A

myogenic- can contract and relax without nervous or hormone stimulation

never fatigues- as long as it has O2 and glucose

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2
Q

what happens if the cardiac muscles run out of O2

A

respire anaerobically- produce lactic acid= heart attacks!!

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3
Q

how can blocked coronary arteries cause heart attacks

A

blocked means they cannot carry oxygenated blood to cardiac muscle
cardiac muscle receive no O2
they respire anaerobically- produce lactic acid- heart attack

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4
Q

why does the right ventricle have a thinner wall than the left ventricle

A

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

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5
Q

what is the only vein that carries oxygenated blood

A

pulmonary vein
from LUNGS to LA

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6
Q

what is the only artery that carries DEoxygenated blood

A

pulmonary artery
from RV to LUNGS

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7
Q

when do AV valves:
- open
- close

A
  • open when pressure is greater BEHIND
  • close when pressure is greater IN FRONT
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8
Q

describe the function of the septum

A

seperates deoxygenated and oxygenated blood

maintains high O2 concentration in oxygenated blood

maintains concentration gradient- enables diffusion at respiring cells

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9
Q

why is there a delay between atrial systole and ventricular systole?

A

all the blood needs to leave the atrium and enter ventricle
atrium walls recoil to push all blood into the ventricle

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10
Q

when do semi lunar valves:
- open
- close

A

open when pressure is greater in ventricles

close when pressure is greater in artery

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11
Q

what is meant by correlation

A

a relationship between variables

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12
Q

what is meant by causation

A

when one variable has an influence on another variable

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13
Q

describe the effects of smoking on blood

A
  • 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
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14
Q

describe the influence of blood cholesterol on the heart

A

high density lipoproteins= low conc cholesterol :)

low density lipoproteins= high conc cholesterol- fatty deposit build up

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15
Q

describe the effect of diet on heart

A
  • high salt increases blood pressure- damage to artery walls
  • lots of saturated fats- low density lipoproteins- higher conc blood cholesterol- fatty deposit build up
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16
Q

function of:
- muscle layer
- elastic layer
- thin endothelium

A
  • muscle layer- constricts and dilates to control volume of blood flowing
  • elastic layer- stretches and recoils- maintains blood pressure
  • thin endothelium- allows diffusion
17
Q

why is the muscle layer in arterioles relatively thicker than arteries

A

needs to constrict to narrow the lumen as arterioles carry blood into the capillaries- need to reduce blood flow

18
Q

why is elastic layer in arterioles relatively thinner than arteries

A

carrying blood at lower pressure than arteries

19
Q

describe 3 features of capillary structure and how they relate to function

A
  • 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
20
Q

why do capillaries have fibrous tissue around them

A

to prevent cells and and proteins from leaking out

21
Q

list the 2 routes by which tissue fluid returns to bloodstream

A

via lymphatic system

via capillaries

22
Q

state what forces tissue fluid out of blood plasma in capillaries and into surrounding tissues

A

hydrostatic pressure due to pumping of the heart

23
Q

how are the contents of the lymphatic system moved

A
  • hydrostatic pressure of tissue fluid that has left the capillaries
  • contraction of body muscles which squeezes the lymph vessels