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Alevel Bio > 8 - Transport in animals > Flashcards

8 - Transport in animals Flashcards

1
Q

Why do animals need metabolic transport systems?

A

High metabolic demand

long distance diffusion not enough

SA:V gets smaller as animals get larger

results increase in diffusion distance and lower relative SA for diffusion to occur

Molecules synthesised in one location, need to be transported to another (hormones, enzymes)

Food digested in one organ system
must be transported to every cell

Metabolic waste products need to be removed and transported to excretory organ.

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2
Q

Define mass transport system.

A

Where substances are transported in a fluid mechanism around the body.

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3
Q

What are the features of an insect’s open circulatory system?

A

A
Haemocoel: An insect’s open body cavity

Haemolymph: Insect blood

No separate tissue fluid, so haemolymph is in in contact with organs and cells

Few vessels so blood pumped straight from heart to haemocoel

Haemolymph holds no O2 or CO2 - gas exchange performed in tracheal system

It transports: nitrogenous waste, disease defence cells

Oxygenated & deoxygenated blood freely mix

Body movements affect circulation

Pressure cannot be changed to support circulation

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4
Q

Give features of a closed circulatory system in fish

A

Blood in vessels - no direct contact to cells​​

​Substances leave by diffusion

Pressure can be maintained and is higher than an open system

Flow can be directed to different tissues and organs

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5
Q

Give features of a single closed circulatory system.

A

Blood flows through the heart once per circulation

Blood flows through 2 sets of capillaries before the heart

1st one for gas exchange - e.g. gills
2nd for substance exchange in organs

LIMITATIONS:

Blood passes through narrow capillaries, lowering blood pressure

Blood returns to heart slowly minimising efficiency

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6
Q

As opposed to other organisms with single closed circulatory systems, why are fish efficient?

A

Countercurrent flow maximising gas exchange

Body weight supported by water

Doesn’t maintain own body temperature

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7
Q

What are features of a double circulatory system?

A

Blood flows through heart twice for every circuit of circulation

2 circuits

1st is the pulmonary circulation - used to carry blood to lungs and oxygenate

2nd is to carry O2 and other nutrients around the body

Per circuit, the blood only passes one capillary network, so pressure is maintained

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8
Q

State and describe the 3 components of blood vessels.

A

Elastic fibres: composed of elastin, can stretch and recoil, providing vessel walls with flexibility Smooth muscle: contracts or relaxes, changing the lumen size Collagen: structural support for vessels (maintains shape

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9
Q

Describe the functions of arteries.

A
  • Carries bloody away from heart to body tissues - Usually carries oxygenated tissue (except pulmonary artery) AWAY from the heart umbilical artery carries fetus’s deoxygenated blood to placenta for gas exchange with mothers blood - Pressure in arteries > veins
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10
Q

Describe the structure and related functions of arteries.

A

Has elastic fibers, smooth muscle, collagen - Elastic fibers enable arteries to withstand force of blood pumped from heart & stretch to take large volumes of blood - Between heart contractions - elastic fibers recoil - helps even out blood surges giving a continuous flow - Artery lined with endothelium, smooth and doesn’t interrupt blood flow

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11
Q

Describe the function and structure of arterioles.

A

Arterioles have more smooth muscle and less elastin than arteries - due to less pulse surge from heart - Arterioles constrict or dilate to control blood flow to organs

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12
Q

Define vasoconstriction and vasodilation.

A

Vasoconstriction - when arteriole smooth muscle constricts, blood vessels constrict, stopping blood flow to capillary bed (stops heat loss)
Vasodilation - when smooth muscle in arterioles relax, blood flows into the capillary bed (increasing heat loss)

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13
Q

What are the adaptations of blood capillaries?

A

Large SA for diffusion of substances into and out of the blood - Total cross-sectional area of capillaries is greater than arterioles, blood flow rate falls - Slower blood movement allows more time for diffusion - Walls are single endothelial cell thick - this shortens diffusion distance.

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14
Q

Give vein adaptations for blood flow back to heart.

A

When veins go back to the heart, blood pressure is too low and it is against gravity 1. Veins have 1 way valves 2. Larger veins run between big, active muscles in body When muscles contract, they give blood extra push in vein 3. Breathing movements in the chest act as pump Pressure in chest changes, squeezing actions move blood into veins of chest of abdomen towards heart

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15
Q

What is blood plasma?

A

Main component of blood, yellow, carries dissolved substances such as blood cells

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16
Q

What is the % composition of components of blood?

A

55% plasma (most of which is water)
45% RBCs, wbc, platelets

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17
Q

What are functions of blood?

A
  • transport of O2 and CO2 to and from respiring cells
  • transport of digested food from small intestine
  • nitrogenous waste products from cells to excretory organs (urea)
  • transport hormones
  • transport of stored food to necessary locations
  • transport of platelets to damaged areas
  • blood contributes to the maintenance of body temp (vasodilation/constriction) and is a buffer to minimise pH changes
18
Q

Define hydrostatic pressure.

A

Pressure due to gravity, increases with depth due to the weight above it
Is also increased by heart surge contraction

19
Q

What are lymph capillaries and what role do they play in fighting infection?

A
  • lymph capillaries form to join larger vessels, they have 1 way valves
  • lymph returns to blood flowing into L & R subclavian veins
    Lymph nodes: exist along lymphatic vessels. Within them are lymph nodes
  • they have lymphocytes that build up in lymph nodes where needed to product antibodies and intercept bacteria. They are ingested by phagocytes
20
Q

How is oxygen carried?

A

O2 levels are low (steep conc. gradient between air in alveoli and erythrocytes) - Oxygen diffuses into rbc and binds to a Hb POSITIVE COOPERATIVITY: 1 O2 binds to a heam group, Hb changes shape to allow the next O2 to bind - Due to O2 being bound to haemoglobin, free O2 conc. in erythrocytes stay low until all haemoglobin is saturated (maintains conc. gradient)

21
Q

How is oxygen released?

A

blood meet body tissue, O2 conc. in somatic cell’s cytoplasm is lower –O2 moves out by diffusion, Hb molecule changes shape each time to release O2 molecule

22
Q

What is partial pressure?

A

In an ideal gas system, many gases make up a mixture, the partial pressure is the individual pressure of each gas.

23
Q

What is an oxygen dissociation curve?

A
  • Graph showing relationship between O2 and Hb at different O2 partial pressures x axis - pO2, y axis - % sats of Hb w/ O2. - Represents the affinity of Hb with O2
24
Q

How are changes in pO2 represented by oxygen dissociation curves?

A
  • Small rise in pO2 - Hb saturation increases at a faster rate as more O2 is available - Curve levels at high pO2 as Hb is saturated - Small drop in pO2 of surrounding (tissue), O2 is rapidly releases from Hb to diffuse into cells –effect enhanced by low pH in tissues vs. lungs (Alkaline conditions - favour for O2 binding to O2 acidic - favour for O2 dissociation
25
Q

What is the effect of CO2 on an oxygen dissociation curve?

A

As pCO2 rises, Hb dissociates O2 faster to remove the CO2, odc moves to the right, so lower Hb/O2 sat Known as the Bohr effect

26
Q

What is the importance of the Bohr effect?

A
  • In active tissues with high pCO2, Hb more readily gives up O2 - In lungs where there is low pCO2, O2 binds to Hb easily.
27
Q

Describe and explain the affinity of fetal haemoglobin.

A
  • Fetus developing in uterus reliant on mother for O2 - Oxygenated blood runs close to deoxygenated fetal blood from umbilical artery in placenta (site of gas exchange) - If affinity for fetal haemoglobin & adult was the same, no O2 would be transferred — fetal haemoglobin has higher affinity to attract O2
28
Q

What are the 3 ways CO2 is transported in the blood?

A
  1. 5% carried dissolved in plasma 2. 10-20% combined with amino group in polypetide chani of Hb forming carbaminohaemoglobin (Hb.Co2) 3. 75-85% converted to HCO3- in erythrocyte cytpolasm – most of the CO2 diffuses that into the blood from cells is transported in the form of HCO3-
29
Q

How is free CO2 produced to be released in the lungs?

A

As blood nears lung tissue, where there is a low CO2 conc. - Carbonic anhydrase catalyses H2CO3<> CO2 + H2O - HCO3- diffuses back into erythrocytes to react w/ H+ to form carbonic acid.

30
Q

What is the basic structure and function of the heart?

A
  • Made of cardiac muscle

Has coronary artery and inelastic pericardial membrane

  • Has septum wall
  • inner dividing wall preventing mixing of oxygenated and deoxygenated blood
31
Q

What is the function of the coronary artery?

A

Supplies cardiac muscle w/ oxygenated blood

32
Q

Describe the blood flow path in the RHS of the heart.

A
  1. Deoxygenated blood enters right atrium from inferior and superior vena cava into right atrium and low pressure
  2. As blood flows in, pressure builds until tricuspid valve opens > blood flows into right ventricle –once both right atrium and ventricle are full of blood, right atrium contracts - all blood forced to right ventricle
  3. Right ventricle contracts, tricuspid valve closes and is stopped from going inside out by chordinous tendons (stops backflow)
  • Blood pumped into pulmonery artery via semilunar valved to capillary bed in lungs - semilunar valve closes.
33
Q
A

A
At the same time as RHS of body…

  1. Oxygenated blood enters left atrium through pulmonary vein from lungs. - Pressure in atirum builds, bicuspid valve opens - blood enters left ventricle
  2. Once both L ventricle and atrium are full, atrium contracts - pumps oxygenated blood through
  3. L ventricle, contracts, pumps oxygenated blood through semilunar valve in aorta and rest of body - semilunary valve closes.
34
Q

Describe the events of the cardiac cycle.

A
  1. Heart is relaxed (diastole) and blood flows into atria
  2. Atria then contract - atrial systole
  3. Higher pressure is generated in atria than ventricles
  4. Blood then flows into ventricles
  5. Ventricles then contract - ventricular systole
  6. Higher pressure in ventricles than atria
  7. Atrioventricular valves close
  8. Blood flows into aorta and pulmonary artery
  9. Higher pressure in aorta and pulmonary artery than in ventricles
  10. Semilunar valves close
35
Q

Explain valves closing with respect to pressure differences.

A

If the pressure is higher in the 2nd location as opposed to the first, the valves close e.g. pressure higher in ventricles than atria, atrioventricular valves close

If the pressure is higher in the 1st location as opposed to the second, the valves open e..g pressure in atria than ventricles, AV valves open

36
Q

Describe and explain the heart sounds.

A

‘Lub-dub’ Lub - atrioventricular valves closing Dub - semulinar valves in aorta and pulmonary artery close

37
Q

Define myogenic.

A

Feature of cardiac muscle, has its own intrinsic rhythm, - Prevents body from wasting resources to maintain basic heart rate.

38
Q

What is the role of the SAN in a heartbeat initiation?

A

Sino-atrial node (natural pacemaker) - starts a wave of excitation in the left and right atrium causing them to contract

Layer of non-conducting tissue prevents excitation from passing to the ventricles and causing them to contract (ensures ventricles only respon to signal from AVN and Bundle of His)

SAN is embedded in right atrium wall

39
Q

What is the role of the AVN in a heartbeat?

A

Picks up electrical activity from SAN

AVN imposes slight delay, ensuring the atria have completely emptied and stopped contracting before the ventricles begin

Then the Bundle of His is stimulated - a bundle of conducting tissue made of Purkyne Fibres

40
Q

Describe each section of an ECG.

A

P wave - atrial systole - wave of depolarisation in atrial walls, atria contracts and blood flows into ventricles

Heart rate calculated from interval between P waves

QRS Complex - Ventricular systole - wave of depolarisation in ventricular wall, ventricles contract, and AV valves close

T wave - ventricular diastole

41
Q

What does each ECG interval represent?

A

PR - time taken for impulse to travel from atria to ventricles

QT - contraction time

Interval between T of one cardiac cycle and Q of the next is filling time

42
Q

Define i) tachycardia ii) bradycardia iii) ectopic heartbeat iv) atrial fibrillation

A

Tachycardia - rapid heartbeat

Bradycardia - slow heartbeat, maybe due to high fitness, severe brady may lead to need for pacemaker

Ectopic heartbeat - extra heartbeat out of rhythm, usually happens once a day.

has abnormal QRS
lack of T wave
gap between extra systole and next cardiac cycle
Atrial fibrillation - e.g. arrhythmia, abnormal heart rhythm. Rapid electrical impulses generated in atria, causes fast contraction (fibrillation). – contraction doesn’t occur properly, only some impulses pass to ventricles so they don’t contract properly.

Alevel Bio (9 decks)

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