Transport in Animals Flashcards

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1
Q

What is an open circulatory system

A

No/very few blood vessels

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2
Q

What is a closed circulatory system

A

Contain blood vessels

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3
Q

What is a double circulatory system

A

Blood flows through
the heart twice for one
complete circulation of
the body

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4
Q

What happens in diastole

A

Walls of atria and ventricles relax
Blood flows into the heart
Pressure forces Av valves open
Blood moves from atria to ventricles
SL valves are closed

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5
Q

What happens in atrial systole

A

Walls of left and right
atrium contract together.

Increases pressure in
atria.

Forces all blood into
ventricles.

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6
Q

What happens in ventricular systole

A

Once full, the ventricle walls start
to contract (millisecond later).

This causes AV valves to shut.

Momentarily all valves closed.

Walls of ventricles contract,
starting at the apex.

Pressure forces blood out of the
ventricles and into the arteries and
SL valves open.

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7
Q

How is the heart initiated and coordinated

A

The Sinoatrial node generates electrical impulses called action potentials. This creates a wave of excitation

The excitation spreads over the atria walls causing them to contract

A band of non-conducting tissue stops the contraction spreading to the ventricles

The excitation is picked up by the atrio-ventricular node, which delays the excitation

The excitation passes down the septum via the bundle of His to the base of the heart and over the purkinjie fibres

This causes the ventricles to contract upwards

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8
Q

What does P represent in an electrocardiogram

A

Excitation of atria

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9
Q

What does QRS represent in an electrocardiogram

A

Excitation of the ventricles

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10
Q

What does T represent in an electrocardiogram

A

Diastole

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11
Q

What is tachycardia

A

Heartbeat is still regular, but faster than usual
Happens as a result of exercise, emotion or fever

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12
Q

What is bradycardia

A

Regular heartbeat but slower than usual
Happens as a result of hypothermia or drugs

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13
Q

What is Fibrillation

A

Chaotic rhythm, heart stops beating properly
Will result in death

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14
Q

What is an ectopic heartbeat

A

An ectopic heartbeat is when the heart either skips a
beat or adds an extra beat.

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15
Q

How are arteries adapted to withstand pressure

A

Thick walls
Lots of collagen
Folded endothelium

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16
Q

How are arteries adapted to maintain pressure

A

Elastic fibres can stretch and recoil
- Vasoconstriction

17
Q

What features help blood return to the heart in veins

A

Skeletal muscle pump
Valves
Gravity
residual pressure

18
Q

What is the equation for the formation of oxyhaemoglobin

A

Hb + 4O2 -> HbO8

19
Q

What is association

A

When oxygen attaches to Hb in the lungs

20
Q

What is dissociation

A

When Hb releases oxygen to cells for respiration

21
Q

Why is the oxygen dissociation curve S-shaped

A

The first oxygen group finds it difficult to attach to a haem groups
Once it attaches there is a conformational change
This means the second and third haems oxygens can attach more easily
This leads to another conformational change
Then the fourth oxygen finds it hard to attach

22
Q

Why does foetal haemoglobin have a higher affinity for oxygen

A

Placenta has a low partial pressure of oxygen
Foetal haemoglobin has a higher affinity for O2 than maternal Hb
At low partial pressure the adult Hb will dissociate and foetal Hb takes up the oxygen

23
Q

What are the three ways CO2 is transported

A

Blood plasma
As carbaminohaemoglobin
As hydrogen-carbonate ions

24
Q

How is CO2 converted into HCO3-

A

CO2 diffuses into RBC and combines with H2O to form carbonic acid

This is catalysed by carbonic anhydrase

The carbonic acid dissociates to release hydrogen ions and hydrogen-carbonate ions

Hydrogen-carbonate ions diffuse out of the blood cell into the plasma

This leads to chloride shift

Hydrogen ions are taken up by Hb to produce haemoglobonic acid

This displaces O2 into the plasma

25
Q

What is BOHR effect

A

More respiration = more CO2
So more hydrogen ions produced
Leading to more oxygen released

26
Q

How does BOHR effect ensure more efficient delivery of O2 when excercising

A

Actively respiring tissue needs more O2 for aerobic respiration to release more ATP

Actively respiring tissue make more CO2

HB involved in transport of CO2

BOHR shift means more O2 is released