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Biology > B8 - Transport in animals > Flashcards

B8 - Transport in animals Flashcards

1
Q

What processes supply single-celled organisms with necessary substances? (5 points)

A
  • Diffusion
  • Osmosis
  • Active transport
  • Endocytosis
  • Exocytosis
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2
Q

Why do multicellular organisms require specialized transport systems? (6 points)

A
  • High metabolic demands
  • Decreased SA:Vol ratio
  • Long diffusion distances
  • Molecules may be made in one place & needed in another
  • Food digested in 1 organ & needs transporting to all cells used in respiration & metabolism
  • Waste products of metabolism ned to be removed from the cells & transported to excretory organs
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3
Q

What is a mass transport system?

A

Transport of substances in a mass of fluid with a mechanism for movement

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4
Q

What is an open circulatory system? (2 points)

A
  • Transport medium is pumped into the body cavity (haemocoel) with low pressure & comes into direct contact wiht the tissues & the cells.
  • Transport medium returns tot he heart through an open-ended vessel.
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5
Q

What is haemolymph?

A

Insect blood that transports food and nitrogenous waste, not oxygen or carbon dioxide

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6
Q

What characterizes a closed circulatory system? (2 points)

A
  • Blood is enclosed in vessels, pumped under pressure, and returns directly to the heart
  • Blood doesn’t come into direct contact with body cells
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7
Q

What are single closed circulatory systems?

A

Blood flows through the heart once per complete circulation

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8
Q

What is the significance of a double closed circulatory system? (3 points)

A
  • Blood travels twice through the heart for each circuit, allowing efficient transport.
  • Once through the heart to the lungs to pick up oxygen and unload carbon dioxide
  • Second time so the oxygenated blood is pumped arround the body.
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9
Q

What are the three main types of blood vessels? (3 points)

A
  • Arteries
  • Capillaries
  • Veins
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10
Q

What is the function of elastic fibers in arteries?

A
  • Provide flexibility, allowing vessels to stretch and recoil
  • Enable them to withstand the force of the blood pumped out of the heart & stretch to take the larger blood volume
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11
Q

What is vasoconstriction?

A
  • Contraction of smooth muscle in arterioles, reducing blood flow to capillaries
  • Vasoconstriction : Narrows lumen, reducing flow.
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12
Q

What is the function of capillaries?

A

Exchange of substances between blood and tissue cells

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13
Q

How are capillaries adapted for efficient exchange? (3 points)

A
  • Large surface area
  • Thin walls (single endothelial cell thick)
  • Slow blood flow
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14
Q

What do veins primarily carry & what are the exceptions to this rule ?

A
  • Deoxygenated blood towards the heart
  • Except pulmonary and umbilical veins
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15
Q

What adaptations help veins return blood to the heart? (3 points)

A
  • One-way valves prevent blood backflow
  • Muscle contractions squeeze the veins forcing the blood towards the heart
  • Breathing movements of the chest acts as a pump
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16
Q

Fill in the blank: The transport medium in open circulatory systems is called _______.

A

haemolymph

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17
Q

True or False: The blood pressure in veins is higher than in arteries.

A

False

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18
Q

What is the main function of blood in the circulatory system? (8 points)

A
  • Transport medium, it transports :
  • Oxygen to, and carbon dioxide from, the respiring cells
  • Digested food from the small intestine
  • Nitrogenous waste products from the cells to the excretory organs
  • Chemical messages (hormones)
  • Food molecules from storage compounds to the cells that need them
  • Platelets to damaged areas
  • Cells and antibodies involved in the immune response.
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19
Q

List three components carried by plasma.

A
  • Glucose
  • Amino acids
  • Hormones
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20
Q

What is the osmotic effect of plasma proteins?

A

Gives blood a relatively high solute potential.

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21
Q

What is tissue fluid?

A

Fluid that fills the spaces between cells and has the same composition as plasma, without red blood cells and plasma proteins.

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22
Q

What happens to hydrostatic pressure as blood moves through the capillaries?

A

It falls / decreases as fluid has moved out and the pulse is completely lost.

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23
Q

What is lymph?

A

Fluid that drains into lymph capillaries, similar in composition to plasma but with less oxygen and fewer nutrients.

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24
Q

Where does lymph eventually return to the bloodstream?

A

Right and left subclavian veins.

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25
Q

What role do lymph nodes play in the immune response?

A

Produce antibodies and intercept bacteria and debris.

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26
Q

What is the Bohr effect?

A

As the partial pressure of carbon dioxide rises, haemoglobin gives up oxygen more easily.

27
Q

What is the shape of red blood cells (RBC) and why is it beneficial?

A

Biconcave shape increases surface area for gas diffusion.

28
Q

What is the composition of haemoglobin? (2 points)

A
  • Large globular protein
  • Made up of four peptide chains, each with an iron-containing haem prosthetic group.
29
Q

How does oxygen bind to haemoglobin?

A

Oxygen binds loosely, forming oxyhaemoglobin in a reversible reaction.

30
Q

What happens during positive cooperativity in oxygen binding to haemoglobin? (3 points)

A
  • The binding of one oxygen molecule makes it easier for subsequent molecules to bind.
  • As the % saturation increases, it forms an S-shaped curve
  • At the highest pO2 the curve levels out because all the haem groups are bonded to the O2 so the haemoglobin is saturated & cant take anymore
31
Q

What is fetal haemoglobin’s advantage compared to adult haemoglobin?

A

Has a higher affinity for oxygen, allowing it to extract oxygen from maternal blood.

32
Q

List the three ways carbon dioxide is transported in the blood.

A
  • Dissolved in plasma (5%)
  • Combined with amino groups in haemoglobin (10-20%)
  • Converted into hydrogen carbonate ions (75-85%)
33
Q

What enzyme catalyzes the conversion of CO2 and H2O to carbonic acid?

A

Carbonic anhydrase.

34
Q

What is the role of the human heart ?

A

Pumps deoxygenated blood to the lungs to get oxygenated and oxygenated blood to the body.

35
Q

What prevents the mixing of oxygenated and deoxygenated blood in the heart?

A

The septum in the inner dividing wall of the heart which prevents the mixing of deoxygenated and oxygenated blood.

36
Q

What structure prevents backflow of blood in the heart?

A

Valves (bicuspis & trucuspid & semi-lumar)

37
Q

What supplies the cardiac muscle with oxygenated blood?

A

Coronary arteries.

38
Q

Fill in the blank: The heart is surrounded by _______ membranes.

A

inelastic pericardial

39
Q

What happens when the right atrium contracts?

A

Forces blood into the right ventricle. (Artial systole)

40
Q

What is the role of tendinous cords in the heart?

A

Ensure the valves are not turned inside out by pressure.

41
Q

Where does deoxygenated blood enter the heart from the upper body?

A

Superior vena cava.

42
Q

Where does deoxygenated blood enter the heart from the lower body?

A

Inferior vena cava.

43
Q

What prevents backflow of blood into the atrium during right ventricle contraction ?

A
  • The tricuspid valve
  • The tricuspid valve closes when the right ventricle contracts, ensuring that blood flows in the correct direction.
44
Q

What structures ensure that the heart valves do not turn inside out during contraction?

A
  • The tendinous cords
  • These cords anchor the valves to the heart muscle, preventing inversion due to pressure changes.
45
Q

What type of blood is pumped from the right ventricle to the lungs?

A
  • Deoxygenated blood
  • The right ventricle pumps deoxygenated blood through the pulmonary artery to the lungs for oxygenation.
46
Q

What valve opens between the left atrium and left ventricle as pressure builds in the atrium?

A
  • The bicuspid valve
  • Also known as the mitral valve, it allows oxygenated blood to flow into the left ventricle.
47
Q

What is the function of the semilunar valves?

A
  • Prevent backflow of blood into the heart
  • These valves close to stop blood from returning to the ventricles after contraction.
48
Q

How do the muscular walls of the left and right sides of the heart differ? (2 points)

A
  • The left side has a thicker muscular wall
  • This is necessary to pump blood throughout the entire body, unlike the right side which only pumps to the lungs.
49
Q

What is the role of the septum in the heart?

A
  • Prevents mixing of deoxygenated and oxygenated blood
  • The septum is the wall that separates the left and right sides of the heart.
50
Q

What happens to the septum after birth? (2 points)

A
  • The gap closes to separate blood types
  • This closure prevents mixing of deoxygenated and oxygenated blood in a healthy heart.
51
Q

What is the duration of a single cardiac cycle in a human adult?

A
  • About 0.8 seconds
  • This cycle includes both diastole and systole phases.
52
Q

What occurs during diastole?

A
  • The heart relaxes and fills with blood
  • Both the atria and ventricles fill with blood, leading to increased volume and pressure.
53
Q

What occurs during systole? (2 points)

A
  • The atria and ventricles contract
  • This phase results in increased pressure and the ejection of blood from the heart.
54
Q

What causes the ‘lub-dub’ sounds of the heartbeat?

A
  • Closing of heart valves
  • The first sound is caused by the closing of atrio-ventricular valves, and the second by the closing of semilunar valves.
55
Q

What is the intrinsic rhythm of cardiac muscle?

A
  • Around 60 beats per minute (bpm)
  • This rhythm helps maintain a steady heart rate without excessive energy expenditure.
56
Q

What initiates the heartbeat in the heart? (2 points)

A
  • The sino-atrial node (SAN)
  • The SAN generates electrical impulses that trigger atrial contraction.
57
Q

What is the function of the atrio-ventricular node (AVN)?

A
  • Imposes a slight delay before stimulating the bundle of His
  • This delay ensures that the atria finish contracting before the ventricles start.
58
Q

What does an electrocardiogram (ECG) measure?

A
  • Electrical activity of the heart
  • It records tiny electrical differences in the skin caused by heart activity.
59
Q

What is tachycardia and when can it be clased as normal? (2 points)

A
  • A rapid heartbeat over 100 bpm
  • It can be normal during exercise or stress but may indicate electrical control problems if abnormal.
60
Q

What is bradycardia and when can it be normal? (2 points)

A
  • A slow heartbeat below 60 bpm
  • It can be normal in fit individuals but may require treatment if severe.
61
Q

What is atrial fibrillation and what does it result in? (2 points)

A
  • An abnormal rhythm with rapid atrial contractions
  • This condition results in ineffective pumping of blood due to irregular impulses.
62
Q

Whats the Haldane Effect

A
  • When hemoglobin is oxygenated, its affinity for CO₂ decreases.
  • This promotes the release of CO₂ from carbaminohemoglobin and bicarbonate conversion, enhancing CO₂ excretion.
63
Q

What are the 3 steps in the electrical control of the heart ?

A
  1. Sino-Atrial Node (SAN) initates heartbeat, causing atria to contract
  2. Atrioventricular Node (AVN) delays electrical impulse ensuring atrial contraction conpletes before ventricles contract
  3. Bundle of His & Purkyne Fibres conducts impulses to ventricles, triggeriing contraction from the apex upwards

Biology (2 decks)

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