Circulatory System Flashcards

1
Q

What does blood transport?

A

Oxygen

Carbon dioxide

Nutrients

Urea

(Heat, Hormones, Antibodies)

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2
Q

“Circulatory system” of unicellular organisms?

A

None

Diffusion across a surface membrane due to the large surface area to volume ratio

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3
Q

Deoxygenated blood leaves the heart to the lungs in…

A

Pulmonary artery

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4
Q

Oxygenated blood enters the heart from the lungs in…

A

Pulmonary vein

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5
Q

Why is a double circulatory system more efficient?

A

It pumps the blood twice and helps maintain a higher pressure so the blood can quickly reach all parts of the body.

In a single circulatory system, blood loses pressure as it passes through the gills

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6
Q

The job of the arteries and veins is?

A

Arteries carry oxygenated blood away from the heart

Veins carry deoxygenated blood towards the heart

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7
Q

Vein between the digestive system and the liver?

A

Hepatic portal vein

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8
Q

Explain the cardiac muscle cells

A

Cardiac muscle cells make up the wall of the heart

Made up of branching cells called muscle fibres that form a strong, mesh-like framework

The cells are striated and there are several nuclei per cell

This framework allows waves of contraction to spread through the heart in a coordinated way

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9
Q

The special properties of cardiac muscle cells?

A

It never gets fatigued (unlike skeletal muscle)

It contracts on its own without nerve stimulation.

Nerves are present only to adjust the rate of contraction

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10
Q

Systole?

A

Phase during the cardiac cycle when the heart is contracting

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11
Q

Diastole?

A

Phase during the cardiac cycle when the heart is relaxing

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12
Q

How are the left and right sides of the heart separated?

A

By a muscular wall called the septum

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13
Q

The function of valves?

A

Valves flow in only one direction through the heart and there’s no backflow of blood

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14
Q

Adaptation of the atria?

A

They have thin walls so they can be stretched while receiving blood but also contract with enough force to push blood through the valves into the ventricles

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15
Q

Blood supply of the cardiac muscle?

A

Coronary circulation: coronary arteries (to the heart)
capillaries
coronary veins (to right atrium)

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16
Q

What is the output of the heart?

A

The stroke volume and the heart rate determine the cardiac output

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17
Q

How can the cardiac output be changed?

A

Actions of the nerves

By hormone: adrenaline from the adrenal glands

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18
Q

Describe the reflex action that causes changes in cardiac output

A

An increase in CO2 is detected by receptors at the aorta and carotid artery

Nerve impulses via sensory nerve sent to the cardiac centre in the medulla

Medulla responds by sending nerve impulses along the accelerator nerve which increases heart rate and causes the heart to beat with more force and increases blood pressure

When CO2 levels return to normal, impulses are sent down the decelerator nerve and the opposite happens

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19
Q

How is a pulse created?

A

The blood leaves the aorta in short bursts of pressure causing the aorta’s wall to stretch.

As the ventricle relaxes, the stretched portion of the aorta recoils increasing the pressure inside it

A wave of stretching and constriction passing along the aorta and the arteries caused by a surged of blood at each heartbeat is known as the pulse

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20
Q

Structure of the arteries

A

They have a thick layer of elastic tissue allowing them to stretch and recoil

Thick smooth muscular walls that help control the flow of blood by constricting and dilating (same for arterioles but due to nerve ending)

Narrow lumen

No valves

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21
Q

Size of capillaries?

A

Wall: one cell thick

Tiny lumen that the RBCs can just fit through

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22
Q

How does the tissue fluid come about?

A

The squamous epithelial cells of the capillary wall are leaky…

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23
Q

The function of tissue fluid?

A

Forms pathway for the diffusion of substances

24
Q

Signs of increased physical fitness

A

The resting heart rate is lower

Stroke volume increases

Length of recovery time (Heart returns to normal more quickly after exercise)

25
Q

How is CO2 carried in the plasma?

A

As HCO3- (hydrogen carbonate) ions

26
Q

Where are RBCs destroyed?

A

Spleen

27
Q

Features of RBCs?

A

Biconcave

Thin walls

Flexible

No nucleus

Hemoglobin (iron-containing protein)

28
Q

Two main actions taken up by WBCs?

A

Phagocytosis

Production of antibodies

29
Q

What are antibodies and how do they work?

A

Antibodies are soluble proteins

They recognize antigens on the surface of pathogens, stick to the surface antigens and destroy them

30
Q

How do antigens destroy pathogens?

A
  1. Causing bacterial cells to stick together…
  2. Acting as a ‘label’ on the pathogen…
  3. Causing bacterial cells to burst open
  4. Neutralising toxins produced by pathogens
31
Q

What is vaccination?

A

Artificially supplying an agent that carries the antigen of a specific pathogen to stimulate an immune response and creation of memory lymphocytes

32
Q

Some agents used as a vaccine:

A
  1. Weakened strain
  2. Dead microorganism
  3. Modified toxins of the bacteria
  4. Just the antigens themselves
  5. Harmless bacteria, engineered to carry the antigens of a pathogen
33
Q

Process of blood clotting:

A

exposure to air ⋙ chemical release ⋙ fibrinogen ⋙ fibrin ⋙ network across the wound ⋙ trapped RBCs ⋙ clot ⋙ scab ⋙ new cells

34
Q

Antigens are determined by ______

A

Genes

35
Q

People who cannot have a heart transplant are:

A

Those with:

  • an advanced lung
  • liver or kidney disease
  • cancer
  • diabetes
36
Q

How to deal with organ rejection?

A

Tissue typing

Immunosuppressive drugs

37
Q

Benefits of aerobic exercise

A

Maintain the glucose level of blood

Strengthen intercostal muscles and increase vital capacity

Stimulates the immune system

Reduces risk of certain cancer

Reduces the level of lipids

38
Q

Define atherosclerosis

A

Hardening of the coronary arteries due to the build of fatty substances like cholestrol (plaque)

39
Q

How do statins work?

A

Statins lower blood cholesterol by inhibiting an enzyme involved in the synthesis of cholesterol and also affect lipid metabolism

40
Q

Where is most of the cholesterol synthesized?

A

Liver

41
Q

What are plant stanol esters?

A

Naturally occurring molecules found in plants that have a similar structure to cholesterol and lower blood cholesterol

Found in vegetable oils and dairy products

42
Q

What do beta blockers do?

A

Beta-blockers are drugs that manage unusual heart rhythms and prevent a second heart attack

Effective treatment for angina

43
Q

How do beta-blockers work?

A

They act on the nervous system by blocking the action of adrenaline at its receptor sites in various parts of the body, including the heart.
Therefore, reducing cardiac output so the heart has to work less hard and needs less O2.

44
Q

What is used to treat angina?

A

Beta-blockers

45
Q

Unit of blood pressure

A

millimeters of mercury

mmHg

46
Q

Blood pressure is expressed as two measurements:

A

Systolic pressure (higher)

Diastolic pressure

47
Q

Risk factors for hypertension:

A
  • High salt content
  • Diseases such as kidney disease
  • Alcohol
  • Pregnancy
  • Genetic factors
  • Stress
  • Lack of exercise
  • Overweight
  • Smoking
48
Q

ACE stands for:

A

Angiotensin-Converting Enzyme

49
Q

Explain the renin-angiotensin system (the system that controls blood pressure)

A

(At low blood pressure) Kidneys ⋙ Renin (enzyme) ⋙ angiotensinogen (plasma protein) ⋙ angiotensin 1 (a peptide of 10 amino acids) ⋙ (ACE) ⋙ angiotensin 2 (a peptide of 8 amino acids) ⋙ constricts blood vessels

50
Q

How are monoclonal antibodies produced?

A

They are produced from a single clone of hybridoma cells

51
Q

A special feature of monoclonal antibodies?

A

Monoclonal antibodies are specific to one binding site on one protein antigen

So, they can target a specific chemical or specific cells in the body

52
Q

Uses of monoclonal antibodies:

A
  • Pregnancy testing
  • Measuring levels of hormones
  • Detecting diseases
  • Treating diseases such as cancer
53
Q

Example of a monoclonal antibody:

A

Herceptin used to treat breast cancer. It binds to the HER2 receptors and blocks their action or marks them for destruction by the immune system.

54
Q

Advantages of monoclonal antibodies:

A
  • Cause no damage to healthy cells

- Used to treat a wide range of conditions

55
Q

How do monoclonal antibodies work against cancer?

A

They bind to particular antigens on the infected or cancerous cells and act in various ways: killing the cell or interfering with the signaling pathways in the cells.

56
Q

What’s HER2 (human epidermal growth factor receptor 2)?

A

A receptor protein on the cell membrane. It responds to chemicals in the blood that switch on mitosis. Some cells have too many HER2 receptors, resulting in uncontrolled cell division that leads to cancer