Cardiovascular system Flashcards

1
Q

What are the 2 main forms of bulk transport?

A

Ventilation and circulation

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2
Q

What are the 2 main contributions circulation has?

A

Bypasses diffusion

Enhances ΔP by moving fluids with different gas contents

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3
Q

What are the 5 main parts of the vertebrate cardiovascular system?

A
Muscular heart
Arterial system
Venous system
Systemic circulation
Pulmonary circulation
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4
Q

Describe the muscular heart

A

Pumps blood around the body
Consists of multiple chambers
Thin auricles/atria
Thick ventricles

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5
Q

Describe the arterial system

A

Transports materials such as O2, nutrients, and hormones at a high pressure

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6
Q

Describe the venous system

A

Removes waste materials such as CO2 and respiratory H2O at a low pressure
Has capacitance

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7
Q

What is capacitance?

A

The ability to store an electric charge

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8
Q

Describe systemic circulation

A

The movement of blood to and from body tissues

Ideally at high flow rates thus at a high pressure

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9
Q

Describe pulmonary circulation

A

The movement of blood to and from the lungs

Ideally at high flow rates but a low pressure

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10
Q

Describe the structure of arteries

A

Lots of elastic tissue and smooth muscle to withstand high pressures

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11
Q

Describe the structure of veins

A

Some have valves to prevent backflow as they operate under low pressure

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12
Q

What is vasoconstriction?

A

The reduction in the diameter of veins

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13
Q

What is vasodilation?

A

The increase in the diameter of veins

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14
Q

How many chambers does a fish heart have?

A

4

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15
Q

What are the chambers in a fish heart?

A

Sinus venosus
Atrium
Ventricle
Conus arteriosus

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16
Q

Describe the sinus venosus in fish

A

The thin-walled venous chamber that receives blood from the duct of Cuvier, coronary veins, and hepatic veins

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17
Q

Describe the atrium in fish

A

A large and thin-walled chamber

Is the 1st chamber that provides the initial acceleration of blood flow around the body

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18
Q

Describe the ventricle in fish

A

The 2nd chamber which is the main propulsive force for cardiac flow
Pumps into the conus arteriosus- continuous with the aorta
Chambers are separated by valves

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19
Q

Describe the conus arteriosus in fish

A

It is short in bony fish and amphibians
Not present in adult amniotes
Capacitance vessel-smooths flow of blood to the gills

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20
Q

What is different in the lungs of lungfish versus fish?

A

Modifications of the partial or complete partition of the atrium into the left and right atria

21
Q

What did the advent of lungs bring?

A

Double circulation
Modification to the conus arteriosus to separate the flow
Semi-lunar valve modified to shunt deoxygenated blood to the lungs (spiral valve)

22
Q

How many chambers are in the amphibian heart?

A

3
2 atria
1 ventricle

23
Q

Describe the structure of the amphibian heart

A

2 atria
1 ventricle
Spiral valve to direct oxygenated blood to enter the ventricle from the left atrium
Conus arteriosus (bulbus cordis) is a swelling of the ventral aorta and is made of smooth muscle

24
Q

Describe the reptilian heart

A

Functionally divided double circulation but there is an additional chamber- cavum venosum
The cavum pulmonae, cavum arteriosus and cavum venousum make up the ventricle

25
Q

Describe the movement of blood through the reptilian heart

A

Venous blood is collected from the body through the sinus venosus
Then to the right atrium
Then to the cavum pulmonae
The into the pulmonary artery into the lungs
Then oxygenated blood returns through the pulmonary veins into the left atrium
Then into the cavum arteriosus
Then into the cavum venosus into the right and left aortic trunks

26
Q

Describe the crocodile heart

A

They have a completely divided ventricle
The left and right sides of the heart are still connected through the Foramen of Panizza
The pressure changes in the pulmonary circulation can change the flow of blood in the heart

27
Q

What is the Foramen of Panizza?

A

A valve between the aortic trunks used to divert blood

Allows the left ventricle to pump to both arches when the right ventricle is shut

28
Q

What happens to the crocodile’s circulation when diving?

A

The lungs are not utilised
Blood is not pumped to the lungs
The right ventricle helps to pump systemic blood

29
Q

How many chambers does the mammalian and avian hearts have?

A

4
2 atria
2 ventricles

30
Q

What happens to the left and right atria in embryos?

A

They are not separated

31
Q

Describe the venous system

A

Fluid is squeezed out of the capillary by blood pressure at the arteriole end
Fluid is pulled back into the capillary by osmotic pressure at the venule end

32
Q

Describe the flow chart of the effects of a low pH, increased waste products and localised depletion on blood flow

A

Low pH, increased waste products, and localised depletion of the blood occurs
This leads to vasodilation of the capillaries
This increases the blood flow
This replenishes the blood, removes waste products, and returns the blood to a normal pH
This leads to vasoconstriction of the capillaries and the cycle begins again

33
Q

Describe the flow chart of the effects of lowering arterial pressure and how it leads to the production of vasopressin

A

The arterial pressure is lowered
Firing in arterial stretch sensors decreases
The hypothalamus released vasopressin
Vasopressin stimulates the kidneys to reabsorb water
This increases the arterial pressure

34
Q

Describe the flow chart of the effects of lowering arterial pressure and how it leads to the production of renin

A
The arterial pressure is lowered 
The kidneys release renin
Renin activates angiotensin
Angiotensin causes vessels to constrict
This increases the arterial pressure
35
Q

Describe the flow chart of the effects of lowering the arterial pressure leads to the widening of vessels

A

The arterial pressure is lowered
There is a decrease in blood flow to the tissue
There is a local accumulation of metabolic waste
There is then autoregulatory widening of vessels
The arterial pressure is then lowered again

36
Q

What is a respiratory protein?

A

A metalloprotein that binds reversibly with oxygen at specific sites

37
Q

Describe haemoglobin Fe

A

Turns from blue to red when oxygen is bound

Present in all vertebrates

38
Q

Describe haemrhythrin Fe

A

Turns from colourless to red/violet when oxygen is bound

Present in sipunculid worms, brachiopods, and priapulids

39
Q

Describe haemocyanin Cu

A

Turns from colourless to blue when oxygen is bound Present in arthropods and molluscs

40
Q

Describe chlorocruorins Fe

A

They are green

Present in fan and feather worms

41
Q

Describe the affinity of respiratory pigments to oxygen

A

Each subunit can bind one oxygen molecule allosterically

Binding of 1 or 2 oxygen molecules changes the shape of haemoglobin to increase the affinity for oxygen

42
Q

Describe the sigmoid dissociation curve of oxygen

A

The closer to the y-axis it is the higher the affinity for oxygen

43
Q

What is myoglobin?

A

A respiratory pigment found in muscles
A single globin unit
No allosteric effect

44
Q

Describe the Bohr shift

A

Respiring tissues will release CO2 which decreases the pH
This causes the Bohr shift in the curve to the right which causes the haemoglobin to increase unloading and enhances oxygen delivery

45
Q

Describe the Root shift

A

Usually, the change in pH does not affect the maximum capacity of oxygen
However, there is an exception in teleost fish blood
Where the acidity decreases the haemoglobin’s maximum capacity for oxygen

46
Q

How is carbon dioxide transported in the blood?

A

Very little is transported as CO2

Most is transported as bicarbonate ions HCO3-

47
Q

What is the equation for CO2 dissociation?

A

CO2 + H2O ⇌ H2CO3⇌ H+ + HCO3-

48
Q

Describe the equation for CO2 dissociation

A

A slow reaction

Enhanced by Carbonic Anhydrase which is present in the endothelium of capillaries and red blood cells