Topic 8 – Exchange and Transport in Animals- The circulatory system Flashcards

1
Q

What is the circulatory system?

A

● Network of organs and vessels

● Enables the flow of blood and transport of oxygen, carbon dioxide, nutrients and other molecules around the body

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2
Q

What are the main components of blood?

A

● Red blood cells
● White blood cells
● Platelets
● Plasma

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3
Q

What are red blood cells also known as?

A

Erythrocytes

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4
Q

What is the function of red blood cells?

A

● Transport O2 from lungs to tissues

● Transport CO2 from tissues to lungs

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5
Q

How do red blood cells transport oxygen to body cells?

A

● Lungs, haemoglobin in RBCs binds reversibly with oxygen to form oxyhaemoglobin
● Tissues, oxyhaemoglobin breaks down to form haemoglobin and oxygen which diffuses into cells

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6
Q

How are red blood cells adapted to their function?

A

● Biconcave disk gives large SA/V ratio, increasing diffusion rate
● Lack nucleus, allowing more space for haemoglobin molecules (increases oxygen carrying capacity of the cell)
● Small and flexible so they can squeeze through capillaries
● Thin giving a short diffusion distance

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7
Q

What is the function of white blood cells?

A

Provide immunological protection

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8
Q

Name two types of white blood cell

A

● Phagocytes

● Lymphocytes

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9
Q

What are phagocytes?

A

● Type of WBC

● Engulf pathogens and digest them in a process known as phagocytosis

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10
Q

What are lymphocytes?

A

● Type of WBC
● Produce antibodies specific to a pathogen
● Produce antitoxins to neutralise toxins

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11
Q

What is the function of platelets?

A

Role in blood clotting

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12
Q

What is plasma?

A

● Pale-yellow liquid portion of the blood

● Contains proteins, nutrients, waste products, hormones, antibodies etc.

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13
Q

How is plasma adapted to its function?

A

Plasma consists mainly of water. This acts as a solvent, enabling the transport of materials around the body.

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14
Q

What are the three main types of blood vessel?

A

● Arteries
● Capillaries
● Veins

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15
Q

What is the function of the arteries?

A

Carry blood away from the heart under high pressure

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16
Q

Describe how the arteries are adapted to their function (6)

A

● Narrow lumen maintains high pressure
● Thick wall to withstand high pressure
● Thick layer of smooth muscle provides strength
● Thick layer of elastic fibres allow stretch and recoil
● Smooth inner lining to reduce friction
● No valves

17
Q

What is the function of the veins?

A

Return blood to the heart under low pressure

18
Q

Describe how the veins are adapted to their function (4)

A

● Large lumen eases blood flow
● Thin wall as blood at low pressure
● Thin layer of smooth muscle and elastic fibres
● Valves prevent backflow of blood

19
Q

What is the function of the capillaries?

A

Allow the exchange of materials at tissues

20
Q

Describe how the capillaries are adapted to their function (4)

A

● Form large network ∴ greater surface area for diffusion
● Walls one cell thick giving a short diffusion distance
● Walls permeable allowing the exchange of substances ● Narrow lumen decreases diffusion distance

21
Q

Describe the double circulatory system in humans

Blood flows through the heart twice in two circuits:

A

● Pulmonary circuit

● Systemic circuit

22
Q

What is the pulmonary circuit?

A

● Part of the circulatory system involving the right side of the heart
● Deoxygenated blood is transported to the lungs
● Gaseous exchange occurs between the alveoli and capillaries in the lungs
● Oxygenated blood is returned to the left side of the heart

23
Q

What is the systemic circuit?

A

● Part of the circulatory system involving the left side of the heart
● Oxygenated blood is pumped to tissues and organs around the body
● Exchange of materials occurs at tissues
● Deoxygenated blood returns to the right side of the heart

24
Q

Name the four chambers of the heart

A

● Left atrium
● Left ventricle
● Right atrium
● Right ventricle

25
Q

Describe the pathway of blood around the body, naming the structures of the heart

A

Pulmonary vein → Left atrium → Left ventricle → Aorta → Body → Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs

26
Q

Why is the left ventricle thicker than the right ventricle?

A

● It pumps blood a further distance

● It must generate a greater force of contraction so blood can be pumped at a higher pressure

27
Q

What is the function of valves in the heart?

A

Prevent the backflow of blood

28
Q

What is cardiac output?

A

The volume of blood pumped out of a ventricle in one minute

29
Q

What is stroke volume?

A

The volume of blood pumped out of a ventricle in one contraction

30
Q

What is heart rate?

A

The number of times the heart contracts in one minute

31
Q

How is cardiac output calculated?

A

cardiac output = heart rate × stroke volume (cm3 min-1) (bpm) (cm3)