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A A A Level Biology > Transport in Animals 3.1.2 > Flashcards

Transport in Animals 3.1.2 Flashcards

(59 cards)

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1
Q

1

Describe what happens during late diastole+ atrial systole

A
  • AV valves open
  • Semi Lunar closed
  • Passive Filling of followed by atrial systole

(blood flows passively from atria»>ventricles
causes muscles in atria to contract PRESSURE INCREASES)

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2
Q

2

Describe what happens during isometric contraction and Ventricular Systole

A
  • AV valves close at end of atrial systole
  • All valves closed as the ventricular muscles contract without shortening (Isometric Contraction)
  • Chordae Tendinae pulled tort to prevent blowback of of valves when Ventricular pressure rises
  • Pressure Builds in ventricles
  • Volume decreases
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3
Q

3

Describe what happens during ventricular systole (ejection)

A

MAIN

  • pressure builds in ventricles
  • semi lunar open and blood ejected to aorta and pulmonary artery
  • muscles shorten as they contract
  • Pressure in aorta rises
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4
Q

4

Describe what happens during ventricular relaxation/diastole

A

-semi lunar valves close as ventricles begin to relax
-pressure in ventricles falls
-AV valves open
CYCLE STARTS AGAIN

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5
Q

Describe the function of papillary muscles

A
  • contract as wave of excitation spreads through ventricular myocardium
  • tighten the chordae tendinae before ventricles contract
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6
Q

What are the 3 stages of the heart cycle

A

atrial systole
ventricular systole
diastole

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7
Q

what does an oxygen dissociation curve show

A

a graphical representation of the behaviour of haemoglobin at different partial pressures(concentrations) of oxygen
- has a sigmoidal shape

partial pressure/ % saturation

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8
Q

why do haem groups join more easily to oxygen after the first join

A

combination of first haem group with an oxygen molecule increases the affinity of the second haem group for oxygen
(allostery)

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9
Q

Describe the Bohr shift if there’s more CO2

A
  • more shift to right
  • more oxygen it delivers
  • less reliance on anaerobic
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10
Q

describe the featires+ structure of haemoglobin

A
  • Quaternery structure of protein (conjugated)
  • 4 subunits per molecule (4 polypeptide chains)
  • Iron Fe2+ in ferrous state and binds with single molecule of oxygen
  • 2 alpha and 2 beta
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11
Q

describe the changes to valves + chambers during late diostole

A

all chambers relaxed
av open
semi lunar closed

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12
Q

what happens during passive filling

A

blood flows passively from atria through open AV valves into ventricles
ventricles stretch to accomodate extra volume of blood

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13
Q

What percentage of ventricle capacity is full in passive filling

A

70%

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14
Q

what is the structure and function of the myocardium

A

-cardiac muscle+ interclated discs + separate muscle fibres&raquo_space;»strengthen muscle tissure + aid impulse conduction

  • lots of mitochondria for rapid aerobic respiration
  • myogenic= generates own excitory impulse
  • long refractory period- eliminates cardiac fatigue
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15
Q

Describe the size and shape of the vein

A

lumen- oval shaped smaller in comp
tunica intima small
tunica media small
tunica externa larger

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16
Q

name the muscle in walls of heart chambers

A

cardiac muscle

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17
Q

name the process that creates pressure in heart chambers

A

systole

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18
Q

How can you treat a patient with narrowing arteries

A

preventing clotting with bypass operation

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19
Q

describe the structure and function of the left ventricle

A

thick walls

generates pressure to force blood into the systematic circulation

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20
Q

describe the structure and function of the chordae tendinae

A
  • short inextensible fibres composed of collegen
  • these connect to free edges of AV valves to prevent blow back of valves when ventricular pressure rises during myocardium contraction
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21
Q

what is the function of the right venrticle

A

generates pressure to pump deoxygenated blood to pulmonary circulation

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22
Q

what is the function of the aortic semi- lunar valve

A

prevents backflow from aorta to left ventricle

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23
Q

what is the function of the bicuspid valve/ left atrioventricular valve

A

ensures blood flow from left ventricle into aortic arch

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24
Q

what is a refractory period

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A

interval between two consecutive effective excitory impulses

25
describe the structure and function of the aorta
- carries oxygenated blood from left ventricle into systemic circulation - has elastic conducting artery +larger lumen which allows wall of aorta to accomodate the surges of blood - as ventricles contract artery expands + when relax elastic recoil of artery forces blood onwards
26
what initiates the heartbeat
sino- atrial node | an excitable myogenic tissue in the wall of the right atrium
27
average intrinsic heart rate?
78bpm
28
which extrinsic factors may modify basic heart rate
- vagus nerve decreases heart rate - accelerator sympathetic nerve increases heart rate - adrenaline + thyroxine increase heart rate
29
describe the structure and function of the tricuspid | / right AV valve
- 3 fibrous flaps w/ pointed ends - flaps pushed together when ventricular pressure exceeds the atrial pressure so blood is propelled through pulmonary artery (instead of back to atrium)
30
-describe the structure and function of superior vena cava
- carry deoxygenated blood back to right atrium of heart | - no venous valves in contrast to veins returning blood from below heart
31
how are capillaries adapted for their function
large s.a walls single endotheial cell thick cross section area larger than artiriole supplying them so descreases blood flow rate allows more time for material to exchange between walls
32
Everything to know about capillaries
- link arterioles with venules - red blood cells travel single file - substance exchange through cell wall - gaps between endothelial cells relatively large so substances pass out to fluid - tight juctions - blood enters oxygenated + leaves less oxygen ore CO2
33
what is significant about cardiac muscle
contracts and relaxes in regular rhythm and doesnt need to rest unlike skeletal muscle
34
which blood vessel suppies the cardiac muscle with oxygen
coronary artery supplies oxygenated blood to cardiac muscle to keep it contracting and relaxing all the time
35
which membrane surrounds the cardiac muscle
inelastic pericardial membranes
36
which side of the heart does desoxygenated blood travel through
right side
37
where does the deoxygenated blood enter
superior vena cava
38
where does the deoxygenated blood leave
the pulmonary artery
39
where does oxygenated blood enter and leave the heart
enters through pulmonary vein and leaves via the aorta
40
what happens as the right ventricle starts contracting
the tricuspid valve closes preventing the backflow of blood
41
what do the tenidinous chords do
make sure valves arent turned inside out by the pressure
42
what does the septum
inner dividing wall of heart which prevents mixing of deoxygenated blood and oxgenated blood
43
what are arterioles
link arteries and capillaries
44
describe features of arterioles
more smooth muscle less elastin little pulse surge contract and dilate to control blood flow into individual organs
45
descibe vasoconstriction in smooth muscle
when smooth muscle contracts it constricts vessel and prevents blood flowing into capillary bed
46
what do arteries do
carry blood away from heart to tissue | exception of heart >>> lungs and umbrial artery fetus to placenta
47
areries are at higher pressure than veins | how are they adapted for this
walls elastic fibres smooth muscle and collegen this enables them to withstand force of blood pumped out of heart + stretch to larger volume of blood HIGHER PRESSURE
48
how are veins adapted for their functions
- between contractions they recoil to origional length to even out surges of blood when heart contracts - endothelium smooth so blood flows easily
49
list some characteristics of veins
- dont have pulse as surges from heart are lost - carry blood TO heart deoxygenated except pulmonary - little elastic fibre - medium sized have valves to prevent backflow - large resovoir of blood + low pressure
50
what happens when veins contract
blood forced towards heart valves prevent backflow breathing can change the pressure
51
what are venules
- join capillaries to veins (deoxygenated) - very thin walls - little elastic muscle - several link to form a vein
52
what happens to bigger veins when muscles contacts
squeeze veins forcing blood towards the heart | when relaxed the valves prevent backflow
53
why are transport systems needed
high metabollic rate low s.a to volume ratio transporting molecules such as hormones, waste products, enzymes and products of digestion
54
define what is meant by an open circulatory system
consists of heart that pumps a fluid called haemolymph trough short vessels and into large cavity called haemocoel as abdomin contracts heart contracts
55
what is meant by a closed circulatory system
blood contained and transported through blood vessles | away from body tissues in continuous circulation pattern
56
what is menat by single circulatory system
pumps by heart blood is oxygenated via gills delivers oxygen to tissues 1 circuit
57
what is meant by double circulatory system
in mammals consists of heart lungs and body blood is pumped twice through heart in one circuit
58
describe the structure and function of the semi lunar/ pulmonary valve
3 cusps/ flaps which are forced together when pressure in pulmonary artery exceeds that of the pressure in right ventricle to prevent backflow
59
describe how the action of the heart is initiated and co-ordinated
1) wave of electrical excitation from sino atrial node spreads over atrial muscle cells causing atrial systole 2) AV node picks up electrical excitation and conducts to apex of ventricles where it is conducted by bundle of his made from purkinje fibres 3) when electrical excitation reaches bundle of his it causes a delay at AVN which causes ventricles to contract from apex causing ventricular systole diastole relaxes and causes repolarisiation

A A A Level Biology (22 decks)

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