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Biology > B8 - transport in animals > Flashcards

B8 - transport in animals Flashcards

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1
Q

Why do animals need a transport system?

A

Higher metabolic demands:
- high O2 & CO2 demands = more waste produced = diffusion alone not enough

small SA:V:
larger distance & smaller SA to absorb nutrients

hormones/enzymes:
- made in one place, needed in another

waste products:
- need transporting to excretory organs & removed

food:
- transported to cells for respiration etc.

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2
Q

components of circulatory system(3):

A

liquid transport medium = blood
vessels = carry transport medium
pumping mechanism to move fluid = HEART

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3
Q

open circulatory system in general

A
  • few vessels to contain transport medium
  • pumped straight from heart to haemocoel(open body cavity), where transport medium has low pressure
  • transport medium has direct contact w/ cells & tissues
  • transport medium returns to heart via open-ended vessel
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4
Q

open circulatory system in insects/invertebrates

A
  • insect blood = haemolymph (doesn’t carry O2 or CO2)
  • haemolymph transports nitrogenous waste & cells to defend against disease
  • heart extends along abdomen & thorax of insect.
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5
Q

Why can’t a steep concentration gradient be maintained in open circulatory systems?

A

The amount of haemocoel flowing to a particular tissue cannot be varied to meet demand, as is an open cavity w/ no blood vessels.

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6
Q

closed circulatory system (general)

A
  • Blood fully enclosed in vessels
  • No direct contact with cells
  • Heart pumps blood at high pressure through progressively smaller vessels
  • substances diffuse through walls of blood vessels (capillaries)
  • blood vessels widen or narrow to adjust amount of blood going to tissues
  • blood pigment carries respiratory gases
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7
Q

single closed circulatory system definition

A

blood passes through 2-chambered heart once for every complete circulation of the body

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8
Q

problems with single closed circulatory system’s efficiency

A
  • blood passes through 2 sets of capillaries before returning to heart
  • blood pressure drops due to narrow capillaries = slowly returns to heart = limits efficiency of exchange process
  • suitable for low activity animals
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9
Q

single closed circulatory system in fish.

A

very active & efficient system
- countercurrent gas exchange system in gills in first set of capillaries = takes O2 from water
- oxygenated blood becomes deoxygenated as is carried to body capillaries.

  • body weight supported by water
  • don’t need to maintain body temp = reduced metabolic demands, so can be very active.
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10
Q

Why are there 2 sets of capillaries in a single closed circulatory system?

A

1st: O2 & CO2 exchanged
2nd: substances exchanged between blood & cells

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11
Q

double circulatory system definition

A

Blood passed through 4-chambered heart twice for every complete circulation of the body

(only pass through 1 set of capillaries before returning to heart = maintain high pressure)

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12
Q

what are the 2 circulations in a double closed circulatory system?

A

pulmonary: heart -> lungs
- blood picks up O2 and unloads CO2
systematic: heart -> body
- releases O2 to cells that need it & return to heart

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13
Q

blood vessel components (3)

A

elastin fibres: stretch & recoil, flexible vessel walls

smooth muscle:
- constrict & relax to change lumen size

collagen: structural support & maintains shape/volume of vessel

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14
Q

Arteries

A
  • carry oxygenated blood away from heart
  • high pressure, maintained by narrow lumen

exceptions:
pulmonary artery - carries deoxygenated blood to lungs

umbilical artery - carries deoxygenated blood foetus to placenta

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15
Q

structure of arteries:

A

thick elastic: withstand force of blood & stretch to take more blood
- stretch and recoil in between heart contractions
- provides continuous blood flow, but you feel a pulse when the heart contracts as elastic fibres aren’t strong enough to eliminate pulse

endothelium thin lining:
smooth for blood to easily flow over

narrow lumen: withstand higher pressure

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16
Q

arterioles

A
  • link arteries & capillaries
  • more muscle, less elastin than arteries

VASOCONSTRICTION: smooth muscle contracts, preventing blood flow into capillary bed

VASODILATION: smooth muscle relaxes, increasing blood flow into capillary bed

17
Q

capillaries

A
  • link arterioles with venules
  • very narrow lumen, so reed blood cells travel single file
    -1 cell thick of endothelium slows rate of blood flow = more time for gas exchange
  • exchange substances through gaps in endothelium
  • oxygenated blood enters from arterioles, deoxygenated blood leaves venules
18
Q

Veins

A
  • carry deoxygenated blood from cells into heart
    (exception = pulmonary vein carries oxygenated blood from lungs into heart)
  • no pulse (lost after entering narrow capillaries)
  • low blood pressure
  • lots of collagen & little elastin
  • wide lumen & thin lining = easy blood flow
  • have valves which prevent backflow of blood
19
Q

Vein adaptations for pumping blood against gravity under low pressure:

A

valves: flaps/infoldings of inner lining. close to prevent blood flowing backwards

bigger veins run through active muscles: muscles contract, squeezing veins, forcing blood towards heart

breathing movement of chest acts as pump: pressure changes move blood to heart

20
Q

tissue fluid

A
  • dissolved substances move out gaps in endothelium
  • large plasma proteins (eg albumin) can’t move out = lowers water potential
  • water moves into blood from surroundings = oncotic pressure
  • blood flowing through arteriole end has high hydrostatic pressure due to heart contractions
  • hydrostatic pressure higher than oncotic, so fluid squeeze out capillaries = TISSUE FLUID
  • substances from tissue fluid diffuse into cells
  • As blood moves through capillaries, hydrostatic pressure decreases as fluid moves out & pulse is lost
  • oncotic pressure now higher than hydrostatic pressure at venule end
  • ## blood returns to veins w/ 90% tissue fluid
21
Q

What is the purpose of albumins?

A
  • large plasma proteins
  • can’t fit through fenestrations in endothelium
  • lowers water potential in blood
  • so that water moves into blood from surrounding fluid = oncotic pressure
22
Q

define tissue fluid

A

fluid cells are soaked in to facilitate substance exchange between cell & blood

23
Q

oncotic pressure value (kPa)

A

-3.3kPa

24
Q

role of lymphatic system

A
  • remove excess fluid & waste from spaces between cells
  • absorb fatty acids from digestive system & deliver to body cells
  • Role in immune system & defence
25
Q

haemoglobin’s oxygen affinity

A

high in lungs
low in tissues

26
Q

oxyhaemoglobin

A

haemoglobin bound to 4 O2

27
Q

Bohr effect

A

High p(CO2) reduces affinity for O2 as more CO2 in respiring tissues = need more O2 to respire
- curve shifts to the right

high CO2 = lower pH = haemoglobin change shape = reduced affinity for O2

28
Q

2 ways of transporting CO2

A

carbaminohaemoglobin: combines w/ amino groups of haemoglobin

carbonic anhydrase:
converted to HCO3- in RBC cytoplasm

29
Q

septum

A

prevents oxygenated and deoxygenated blood mixing from left and right side of heart

30
Q

pericardium

A

membrane surrounding heart
- lubricates & stops friction

31
Q

tendinous chords

A

hold down valves & prevent inversion

32
Q

papillary muscles

A

anchor
- outgrow of muscle for tendinous chords to attach to

33
Q

coronary artery

A

carries O2 to heart
if blood clot: no O2 for cells = no aerobic resp & cells die due to myocardial infarction

34
Q

ecg

A

electrocardiogram

35
Q

bradycardia

A

<60bpm
in healthy people/fit

36
Q

tachycardia

A

> 100bpm
during exercise, scared, angry etc.

37
Q

atrial fibrilation

A

abnormal heart rhythm
- rapid electrical impulse in atria
- contract v. fast but don’t contract properly = blood not pumped efficiently

38
Q

ectopic heart beat

A

irregular

1 a day is common but frequent = serious condition

Biology (20 decks)

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