C6 - Transport Systems in Mammals Flashcards

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1
Q

Why do you larger organisms have transport systems?

A

Diffusion would take too long as they have a small surface area to volume ratio reducing the rate of diffusion.

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2
Q

What are the components of a specialised circulatory system?

A

The heart

The fluid in which substances are transported

Vessels through which the fluid flows

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3
Q

What occurs in an open circulatory system?

A

The system consisting of the hearts that pumps the fluid ‘haemolymph’ through the short vessels went into a large cavity called the haemocoel.

In the haemocoel, the haemolymph directly bathes organs and tissues enabling the diffusion of substances.

When the heart relaxes, the haemolymph blood is sucked back via pores called ostia.

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4
Q

What is an open circulatory system?

A

When blood flows freely through the body cavity, carrying nutrients to their cells.

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5
Q

What is the closed circulatory system?

A

One where blood is fully enclosed within blood vessels at all times.

Blood is pumped through vessels and substances enter and exit via diffusion.

This is beneficial as in a closed system pressure can be created.

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6
Q

Why is a closed circulatory system beneficial?

A

Pressure can be created and blood pressure can be maintained throughout the body

Pressures can differ in the pulmonary and systemic systems

Blood supply to different organs varies depending on the function and need for example the gut needs more blood during digestion

Lower volumes of transport fluid, the blood, are needed to keep the system moving than in an open system

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7
Q

What’s a double circulation system?

A

When there are two circuits - one is the circuit between the lungs and the heart (the pulmonary circuit) and the other is between the body and the heart (the systemic circuit)

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8
Q

What are the advantages of a double system?

A

Blood pressure can be maintained around the body rather than falling due to resistance to flow as it moves through the lungs and other tissues.

Oxygenated blood doesn’t mix with deoxygenated blood making oxygen uptake from exchange more efficient

There is a greater efficiency of the delivery of nutrients and oxygen

Blood pressure and the systemic and pulmonary circulation is can be maintained at different pressures

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9
Q

What are the different blood vessels?

A
Arteries
Veins
Capillaries
Arteriolar
Venules
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10
Q

What is the structure of arteries?

A

They have a thick wall with large amounts of smooth muscle and elastic fibres

The inner endothelia lining is smooth to reduce friction

There are no valves

They have a small lumen

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11
Q

What is the function of arteries?

A

They keep the pressure high as the blood is distributed throughout the circuit.

The artery wall stretches during ventricular systole and recoils during ventricular diastole.

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12
Q

What is the bloodflow of arteries?

A

They take blood away from the heart under high-pressure

High-pressure pulses as the pressure fluctuates

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13
Q

What is the structure of veins?

A

They have a wide lumen and a thin walls with a small amount of muscle and elastic tissue.

Semilunar valves are found all along the length

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14
Q

What is the function of veins?

A

Blood is carried on the low-pressure and the thin wall makes it easier to compress the vessel when the skeletal muscles contract around them.

This aids blood flow through the veins

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15
Q

What is the blood flow within veins?

A

They return blood to the heart

Flow is slow because the pressure is low

There is no pulse

The valves prevent back flow and keep the flow moving in one direction which is necessary with the low-pressure

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16
Q

What is the structure of capillaries?

A

The wall is a single layer of squamous epithelial cells with no elastic on muscle tissue

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17
Q

What is the function of capillaries?

A

They connect arterioles and venules forming a vast network within the tissues.

The size of the network provides a large overall cross-sectional area for exchange of materials between the blood and surrounding tissues

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18
Q

What is the blood flow within capillaries?

A

See allows the flow between the arterioles and venules.

Rate of flow is slow as the pressure is low.

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19
Q

What is the structure, function and blood flow within arterioles?

A

They have a thin wall mainly of muscle and some elastic fibre

They carry blood between arteries and capillaries. They regulate the flow and distribution.

Smooth-muscle contracts to constrict the lumen or relax and dilate the lumen to allow blood pressure and distribution to be regulated.

20
Q

What is the structure, function and blood flow within venules?

A

They have very thin walls of muscle and elastic fibres.

They carry blood from capillaries back to the veins.

The wall has only a thin layer of muscle which does not provide any assistance in blood flow.
Valves along the length of the venue prevent back flow.

21
Q

What moves blood forwards within arteries?

A

Elastic fibres contribute to blood pressure is elastic fibres and arteries stretch during systole and recoil in diastole, propelling the blood forwards.

22
Q

How is blood pressure calculated?

A

Systolic pressure divided by diastolic pressure measured in millimetres of mercury.

23
Q

What is systolic pressure?

A

Pressure created by the contraction of the left ventricle / the force generated by the left ventricle contracting

24
Q

What is diastolic pressure?

A

Pressure reflecting the elasticities of artery walls

25
Q

How does blood flow in veins?

A

There is no pulse so skeletal muscles around the veins contract and relax. Surrounding muscle contraction increases blood pressure.

As they relax blood pressure falls so more blood from the capillaries can flow in.

Valves prevent back flow

26
Q

What is hypertension?

A

A permanently raised high blood pressure

27
Q

What is hypotension?

A

Are permanently lowered blood pressure

28
Q

What can hypertension cause?

A

Damage to the lining of artery walls causing an aneurysm. This could lead to a heart attack or stroke.

Damage to heart valves

Kidney disease as the capillaries within the kidney are damaged by constant high-pressure

29
Q

What can hypotension cause?

A

Weakness and tiredness

Dizziness and fainting

Coma and possible death

30
Q

What risk factors can contribute to hypertension?

A
Smoking
Being obese or overweight
A diet high in salt
Excess alcohol consumption
High levels of stress
Age - the older you are the greater the risk
Gender – males have increased risk
Low levels of exercise
31
Q

What is the name of the vein and artery that travels to and from the head and neck?

A

Carotid artery (to the head)

Jugular vein (away from head)

32
Q

What is the name of the vein and artery that travels to and from the upper limbs?

A

The subclavian artery (to the fore limbs)

The subclavian vein (away from upper body)

33
Q

What is the name of the vein and artery that travels to and from the lungs?

A

Pulmonary artery (to the lungs)

Pulmonary vein (to the left atrium)

34
Q

What is the name of the vein and artery that travels to and from the liver?

A

Hepatic artery (from the heart)

Hepatic portal vein (from the stomach and intestines to the liver)

Hepatic vein (to the heat)

35
Q

What is the name of the vein and artery that travels to and from the kidney?

A

Renal artery

Renal vein

36
Q

What is the name of the vein and artery that travels to and from the gonads (reproductive glands)?

A

Genital artery

Genital vein

37
Q

What is the name of the vein and artery that travels to and from the lower body / hind limbs?

A

Iliac artery

Iliac vein

38
Q

What is tissue fluid?

A

The fluid that surrounds body cells.

It has a similar composition to blood plasma except it contains no large proteins and no cells.

Excess tissue fluid that’s not reabsorbed is known as lymph.

39
Q

What is the function of tissue fluid?

A

To supply cells with nutrients and remove waste products.

40
Q

What is hydrostatic pressure?

A

Pressure created by a fluid pushing against the sides of a vessel.

41
Q

What is oncotic pressure?

A

Also known as colloid osmotic pressure, it is the force due to the tendency of plasma proteins and other substances to lower the water potential.

It tends to pull fluids into the circulatory system.

42
Q

What is another name for colloid osmotic pressure?

A

Oncotic pressure.

Also known as colloid osmotic pressure, it is the force due to the tendency of plasma proteins and other substances to lower the water potential.

It tends to pull fluids into the circulatory system.

43
Q

How is tissue fluid formed?

A

(Arteriole end)
Slow blood flow through many capillaries and high hydrostatic pressure results in small molecules and water leaving the capillaries.

Larger protein molecules remain in the capillaries/blood plasma and create an oncotic force. This is negative and pulls the water back in. Hydrostatic pressure is greater than oncotic so there’s a net outward force.

(Venule end)
Hydrostatic pressure has now fallen due to loss of fluid so oncotic pressure is higher than hydrostatic, drawing fluid back into the capillary.

Some tissue fluid doesn’t return and drains into the lymphatic system which carries excess tissue fluid back to veins in the neck.

44
Q

What creates the oncotic pressure in the formation of tissue fluid?

A

The large protein molecules which remain in the capillary blood plasma.

45
Q

Why does the exchange of fluid occur in capillaries?

A

They’re made of very thin, flat, squamous epithelial cells with many fenestrations (gaps) which make the walls permeable to small molecules.

They’re ‘leaky’ so materials can be exchanged.