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AS BIO UNIT2 > 2.3 Adaptations for Transport: Animals > Flashcards

2.3 Adaptations for Transport: Animals Flashcards

1
Q

Outline key features of a transport system

A
  • a medium to carry materials
  • a pump to move fluid (ie the heart)
  • valves to maintain one way blood flow
  • respiratory pigment to increase volume of oxygen transported
  • branching blood vessel network
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2
Q

Define an open circulatory system

A

The blood does not move around the body in blood vessels but bathes the tissue directly while held in a cavity called the haemocoel
—> insects

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3
Q

Define and explain a closed circulatory system

A

Blood moves in blood vessels. Two types:
- single circulation - blood move through heart once in passage around body
- double circulation - blood passes through heart twice in circuit around body

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4
Q

Explain the pulmonary circuit

A
  • serves the lungs
  • right side of heart pumps deoxygenated blood to the lungs
  • oxygenated blood returns to lungs from left side of heart
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5
Q

Explain the systemic circuit

A
  • serves the body tissues
  • left side of the heart pumps oxygenated blood to the tissues
  • deoxygenated blood from body returns to right side of heart
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6
Q

Why is double circulation more effective than single?

A

Oxygenated blood can be pumped around body at a high pressure

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7
Q

Explain the role of the arteries

A
  • carry blood away rom heart
  • thick muscular walls to withstand high blood pressure
  • branch into arterioles which branch to capillaries
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8
Q

Explain the role of capillaries

A
  • vast network
  • penetrate all tissues and organs
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9
Q

Explain the role of veins in

A
  • large lumen diameter but thinner walls than arteries to decrease blood pressure and flow rate
  • semilunar valve to ensure one way flow
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10
Q

Explain the structure of arteries and veins, and how this relates to function.

A
  • tunica intima (inner most layer) also known as endothelial layer. Reduces friction and maintains minimum resistance to blood flow
  • tunica media (middle layer) is thicker in arteries than veins. It allows stretching accommodate changes in blood flow and pressure
  • tunica external (outer layer) is made of collagen to resist over expansion of the vessels
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11
Q

Define myogenic contraction

A

Where the heartbeat is initiated within the cardiac cells themselves, and is not dependant on nervous or hormonal stimulation

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12
Q

State the meaning of systole and diastole

A

Systole: heart muscle contracts
Diastole: heart muscle relaxes

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13
Q

Explain atrial systole

A
  • atrium walls contract and blood pressure in atria increases
  • pressure in atria greater than in ventricles so AV valves (tri and bi) open
  • blood forced into ventricles which are relaxed
  • ventricular diastole coincides with atrial systole
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14
Q

Explain ventricular systole

A
  • ventricle walls contract and increase blood pressure in ventricles is greater than in atria so AV close to prevent backflow of blood
  • pressure in ventricles greater than in aorta and pulmonary artery so semi lunar valances open and blood leaves via pulmonary artery and aorta artery
  • pulmonary artery carries deoxygenated blood to lungs and aorta carries oxygenated blood around body
  • atrial diastole coincides with ventricular systole
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15
Q

Explain diastole

A
  • ventricles and atria are relaxed, pressure drops so semi lunar valves close
  • both atria fill with blood which is returned to heart via vena cava and pulmonary vein
  • AV valves open as P atria greater than P ventricle
  • cycle begins again with atrial systole
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16
Q

Describe the flow of blood through the heart

A
  1. Left atrium relaxes and receives oxygenated blood from the pulmonary vein
  2. When full, the pressure forces open the bicuspid valve between the atrium and ventricle
  3. Relaxation of left ventricle draws blood from left atrium
  4. The left atrium contracts, pushing remaining blood into left ventricle through the valve
  5. The left atrium relaxes and left ventricle contracts. Strong muscle walls exert high pressure
  6. This pressure pushes blood up out of heart through the semi lunar valves into the aorta. The pressure also closes the bicuspid valve, preventing back flow of blood into left atrium
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17
Q

What is the sino atrial node?

A
  • cluster of specialised cardiac cells in the wall of the right atrium that act as a pacemaker
  • initiate a wave of electrical excitation across the atria to generate contraction of the heart muscle
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18
Q

Explain the control of the heartbeat

A
  • wave of electrical stimulation arises at the SAN and spreads over both atria so they contract together
  • ventricles are electrically insulated by connective tissue, except from the AVN which introduces a delay in transmission
  • AVN passes the excitation down the nerves of bundle of His and to the apex of the heart. Excitation is transmitted to the Purkinje fibres in ventricle walls that carry it up the muscle
  • impulses cause the cardiac muscle in each ventricle to contract simultaneously
  • pushes blood up to aorta and pulmonary artery, emptying ventricles completely
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19
Q

What is the atrio ventricular node?

A
  • only conducting area of tissue in the wall of the heart between the ventricles and atria, through which electrical excitation passes from atria to conducting tissues in wall of ventricles
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20
Q

What is an ECG?

A

A trace of the voltage changes produced by the heart detected by electrodes in the skin

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21
Q

What is P on an ECG?

A
  • voltage generated by SAN with contraction of atria. Small amplitude as atria have little muscle
  • atrial systole
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22
Q

What is the QRS wave on the ECG?

A
  • depolarisation and contraction of ventricles, high amplitude due to thick muscle walls
  • AVN transmit electrical impulse through bundle of His
  • ventricular systole
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23
Q

What is T on the ECG?

A
  • repolarisation of the ventricle muscle
  • diastole
24
Q

What is the PR interval on an ECG?

A

Time taken for excitation to spread from atria to ventricles via the AVN

25
Q

What is an indication of a heart attack?

A

A wide QRS

26
Q

What is an indication of enlarged ventricle walls?

A

High R

27
Q

What is an indication of atrial fibrillation?

A

Rapid heart rate and may lack a P wave

28
Q

What is an indication of blocked coronary arteries and atherosclerosis?

A

Changes to heigh of ST segment and T wave

29
Q

What is an arrhythmia?

A

Abnormal heart rhythm

30
Q

What is fibrillation?

A

Electrical activity of heart not in sync

31
Q

What is myocardial infarction?

A

Heart attack caused by a blockage in the coronary arteries that stops blood flow reaching heart muscles

32
Q

What is cooperative binding?

A

The increasing ease with which haemoglobin binds its second and third oxygen molecules as the conformation of the haemoglobin molecule changes

33
Q

3 ways CO2 is transported

A
  • 5% is dissolved in plasma
  • 10% combines to haemoglobin to make carbaminohaemoglobin
  • 85% transported in hydrogen carbonate ion
34
Q

What enzyme catalyses the combination of CO2 and water

A

Carbonic anhydrase

35
Q

Describe the reactions in red blood cells involving CO2

A
  • carbon dioxide in blood diffuses into red blood cell
  • carbonic anhydrase catalyses reaction of CO2 and H2O, making carbonic acid
  • carbonic acid dissociate into H+ and HCO3- ions which diffuse out of red blood cell into plasma
  • to maintain electrochemical neutrality, chloride ions diffuse into RBC from plasma - chloride shift
  • H+ ions cause oxyhaemoglobin to dissociate into oxygen and haemoglobin which releases O2, so diffuses out of RBC into tissues
36
Q

What happens when CO2 concentration increases?

A

Haemoglobin releases oxygen more readily

37
Q

Define the Bohr effect

A

The movement of the oxygen dissociation curve to the right at a higher partial pressure of carbon dioxide because at a given oxygen partial pressure, haemoglobin has a lower affinity for oxygen

38
Q

What is tissue fluid?

A

Plasma without plasma proteins, forced through capillary walls, bathing cells and the places between the,

39
Q

Arterial end of blood supply

A
  • blood under high pressure
  • hydrostatic pressure greater than osmotic so pushes liquid outwards from capillary to spaces between surrounding cells
  • water drawn in by osmosis
40
Q

Venous end of blood supply

A
  • low pressure
  • osmotic pressure greater than hydrostatic pressure
  • pushes water out into capillaries by osmosis
  • tissue fluid pick up carbon dioxide and other waste
  • some drain into lymph system
41
Q

Where does the lymph empty?

A

Veins, restoring blood volume

42
Q

Composition of lymph compared to blood

A
  • more fat, lipids and carbon dioxide
  • less oxygen and nutrienrs
43
Q

How can myoglobin perform a useful function for muscle tissue?

A
  • myoglobin saturated and has high affinity for O2
  • acts as O2 store
  • used when muscle excersising heavily
44
Q

A change in the blood of an athlete training at high altitude

A

More RBC

45
Q

Importance of oxygen dissociation curve of fetal haemoglobin

A
  • higher affinity for O2 so absorbs from mother
  • fully saturated at low O2
46
Q

Explain why a low protein diet would result in fluid retention in tissues

A
  • low protein reduces plasma protein levels
  • plasma proteins decrease water potential
  • higher water potential in low protein diet
  • lower water potential gradient
  • more water remain in tissue fluid
47
Q

Function of bundle of His and purkinje fibres

A
  • conduct wave apex of heart
  • ensure contraction from base upward
48
Q

What impact does temp have on partial pressure of O2 that haem becomes saturated?

A
  • as temp increases higher O2 conc needed to saturate
  • increase temp means more O2 is released
49
Q

Explain how increase in minute volume results in decrease pCO2 of blood in alveolar capillaries

A
  • more CO2 exhaled
  • increased diffusion gradient from blood into alveoli
50
Q

Why would macrocytic anaemia cause a reduction in the oxygen carrying capacity of blood

A
  • fewer cells so lower total SA
  • larger cells so harder for RBC to pass through capillaries
51
Q

What is the function of the layer of connective tissue between atria and ventricles

A

Prevent depolarisation of atria passing to ventricle so that ventricles don’t contract downward

52
Q

Formation of tissue fluid

A
  • at arteriole end there is high hydrostatic pressure which results in ultrafiltration of blood so water, glucose, fatty acids, amino acids, ions and oxygen is pushed out to form tissue fluid
  • RBC, platelets and proteins and some water remains in blood stream
  • at venous end there is high osmotic pressure and low water potential so water rebasorbed into capillaries
  • remainder of tissue fluid is drained into lymphatic system and reabsorbed to blood stream near heart
53
Q

Explain why hydrostatic pressure decreases as blood travels along the capillaries

A
  • capillary loses water
  • increase in resistance
54
Q

Why does osmotic pressure remain constant as blood travels along the capillaries

A
  • osmotic pressure relates to plasma proteins which cannot leave capillary as too large and so osmotic pressure does not change
55
Q

Explain how the structure of the wall of the arteriole can reduce blood flow to a capillary network

A
  • muscle contracts which reduces lumen diameter
56
Q

Explain role of endoderm in uptake of water into xylem and generation of root pressure

A
  • waterproof casperian strip that forces water from apoplast to symplast
  • active transport of ions into xylem
  • water moves from endo to xylem by osmosis
  • increases hydrostatic pressure

AS BIO UNIT2 (7 decks)

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