Biology > 3.1.2 > Flashcards

3.1.2 Flashcards

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1
Q

Why is a transport system needed?

A

*Low SA:V
*High metabolic rate
*Transport hormones, products, remove waste

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2
Q

Describe how Open circulatory systems work

A

*Small invertebrates e.g. insects
*Transport medium (haemolymph) pumped directly to open body cavity (haemocoel)
* Few vessels
*Low pressure
*Transports food nitrogenous waste, not gases
*After exchange, returns to hear in open ended vessel

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3
Q

How are gases transported in insects?

A

Tracheal system

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4
Q

Describe how closed circulatory systems work

A

*All vertebrates, some invertebrates e.g. mammals/ earthworms
*Transport medium (blood) remains inside blood vessels
*Under high hydrostatic pressure
*Substances Leave vessels by diffusion/pressure
*Flow can be adjusted, more efficient
*Gases carried

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5
Q

What is the open body cavity in insects called?

A

haemocoel

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6
Q

What is the transport medium in insects called?

A

Haemolymph

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7
Q

Describe how Single closed circulatory systems work

A

*Blood only passes through heart once per cycle ( 1 circuit)
*2 sets of capillaries
-Heart → capillaries in gills (oxygenated)
-Through capillaries in body back → heart
*Not efficient but efficient in fish from count current exchange

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8
Q

Describe how double closed circulatory systems work

A

*Blood passes through heart twice per cycle, 2 separate circuits
*1st- heart → lungs (gas exchange
*2nd heart → body (deliver O2 & nutrients collect cells)

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9
Q

What is the circuit of the heart to the lungs in mammals called?

A

Pulmonary circuit

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10
Q

What is the circuit of the heart to the body in mammals called?

A

*Systemic circuit

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11
Q

What are the functions of the 3 components of blood vessels?

A

*Elastic fibres- With elastin can stretch and recoil for heart contractions, reduce pulse
*Smooth muscle- contracts and relaxes to change lumen size
*Collagen- structural support

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12
Q

What is the function of arteries and arterioles

A

*Carry oxygenated blood away from heart to tissues

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13
Q

What are the exceptions of arteries (carry deoxygenated blood not oxygenated)

A

*Pulmonary artery- heart to lungs
*Umbilical artery- fetus to placenta

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14
Q

Describe the structure and function of the arteries.

A

*Carry oxygenated blood away heart
*Contains folded endothelium- expands at high pressure
*Elastic layer- maintains high pressure
-Stretches to increase blood volume
-reduces pulse, stretching and recoiling at heart contractions
*Smooth muscle- Thicker than veins, vasoconstriction and dilation can occur
*Collagen layer- structural support- high pressure
*Thick walls- from high pressure, largest diameter

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15
Q

List the order of blood vessels

A

-Arteries
-Arterioles
-Capillaries
-venules
-Veins

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16
Q

Why are elastic fibres so important in arteries?

A

*Maintains higher pressure
*Stretch and recoil to smooth out pressure surges at heart contractions

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17
Q

Why does vasoconstriction and dilation occur in smooth muscle?

A

*Regulates blood flow to areas with higher metabolic demand
*Regulates pressure surges

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18
Q

Describe the structure and function of the arterioles.

A

Link arteries and capilaries
*Smooth endothelium
*Elastic layer- thinner than arteries as pressure lower
*Smooth muscle-Thicker than arteries, have to reduce flow to capillaries, (vasoconstriction)
*Thinner collagen- less Pressure, wall less thick

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19
Q

Why is smooth endothelium important in Arterioles, capillaries, venules and veins,

A

*Smooth efficient flow

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20
Q

What is systolic pressure

A

pressure measuring the force your blood exerts on artery walls during heart contraction (systole)

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21
Q

What is hydrostatic pressure?

A

Hydrostatic pressure, fluid pressure, is defined as the pressure exerted by a fluid at rest due to weight.

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22
Q

Why does vasoconstriction occur?

A

*Smooth muscle constricts, lumen diameter decreases
*Reduces blood flow
*Increases pressure

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23
Q

Why does vasodilation occur?

A

*Smooth muscle relaxes, lumen diameter increases
*Increases blood flow
*Decreases pressure

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24
Q

Describe the structure and function of the capillaries

A

*Towards and away heart Link arterioles and venules
*Smooth endothelium
*No elastic, smooth muscle/ collagen
*Very low pressure (1-2mmHg)
*Supplies cells
*One cell thick- short diffusion distance
*Small lumen diameter- increased diffusion
*Small gaps in walls, liquid and wall molecules forced out
*Large network- high SA:V

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25
What is the function of venules and veins?
*Carry deoxygenated blood from cells to heart
26
What are the exceptions of veins (carry oxygenated blood instead of deoxygenated)
*Pulmonary vein- Oxygenated blood from lungs to heart *Umbilical vein- placeta to fetus
27
Describe the structure and function of the Venules
*Connects capillaries and veins *No elastic, collagen *Thin layer of smooth muscle *Thin smooth wall
28
Describe the structure and function of the veins.
*Smooth endothelium *Elastic and smooth muscle layer thin- from low pressure/ no pulse surges, flow doesn't need controlling as much *Lots of collagen *Thin wall- low pressure *Wide lumen for efficiency *Valves- prevent backflow from low pressure
29
What factors other than the heart, ensure blood in veins keeps flowing.
*Breathing movements of the chest act as a pump *Big veins run between muscles- muscle contractions force blood along.
30
Describe the main 3 white blood cells
*Neurophils -immune response, -multilobed nucleus -Hydrolytic enzymes lots of cytoplasm *Eosinophils -Very granular cytoplasm *Lymphocytes -Very large nucleus -produce antibodies -very small cells
31
Describe the components of plasma
*Yellow liquid that carries substances e.g. hormones red blood cells *55% of the blood -Contains albumin- maintains osmotic potential -fibrinogen- important for blood clotting -Globulins-transport of immune system
32
Describe the components of platelest
*Fragments of large cells (megakaryocytes) *Found in bone marrow *involved in clotting
33
what is tissue fluid?
*At high pressure liquid and small molecules forced out of capillary walls baths tissues = tissue fluid
34
What is hydrostatic pressure
*Pressure exerted by a liquid -In blood this is pressure from blood surge
35
What is oncotic pressure?
*Tendency of water to move into blood -Arises from plasma proteins giving blood a low water potential.
36
Why does tissue fluid leave blood vessels?
*Blood enters capillaries from arterioles. -Change in diameter = high hydrostatic (pressure of liquid) pressure -Hydrostatic pressure higher than oncotic pressure -Forces water/ molecules e.g. glucose, O2 out capillaries at arterial end -baths substances in nutrients, waste picked up
37
why does reabsorption of tissue fluid happen?
*After water/ small molecules (tissue fluid move out *Large molecules e.g. plasma proteins- albumin- remain -Lower water potential, increasing oncotic pressure *And at venule end hydrostatic pressure (pressure of liquid) begins decreasing from exit tissue fluid *Oncotic higher than hydrostatic pressure *H2O moves in via osmosis till equilibrium reached. *Remaining tissue fluid absorbed into lymphatic system (now lymph) -Eventually drains to blood stream- subclavian vein.
38
What is the composition of lymph?
*Similar to plasma/ tissue fluid -No plasma proteins, Less nutrients/ O2 (as absorbed by cell from tissue fluid)
39
When does tissue fluid become lymph?
*The remaining tissue fluid that is not reabsorbed back to the blood vessels via osmosis *Rejoins via lymph vessels, lymphatic system, before draining back to heart
40
What are lymph nodes?
*Along lymph vessels -where lymphocytes build up to produce antibodies -Intercept bacteria/ debris and digest phagocytes here before bringing back to blood
41
How long do red blood cells last and why?
*120 days *Adaptations e.g. no nucleus, have to be made in bone marrow
42
What is the equation when haemoglobin binds to oxygen?
*Hb + 4O₂ ⇋Hb(O₂)₄
43
How is O₂ transported in the lungs?
*When blood enter capillaries in lungs, it has low conc of O₂ *Alveoli have lots, steep conc grad. Diffusion. *Oxygen bind to haemoglobin *Positive cooperativity occurs - As O₂ bound to haemoglobin, low conc of free oxygen, so steep conc maintained
44
What is Positive cooperativity
After 1 Oxygen binds, haemoglobin changes shape, others easier to bind.
45
How is Oxygen transported at the tissues?
*Oxygen in cytoplasm of respiring tissues lower than red blood cells *Moves down conc grad to tissues via diffusion *Once first haemoglobin removed, changes shape- easier to remove remaining positive coopertivity *Bohr effect= O2 more easily given up by haemoglobin
46
What does the Oxygen affinity curve show?
*Liking of haemoglobin to oxygen -Percentage saturation of haemoglobin over partial pressure O₂ -Curve becomes steeper before leveling to plateau -from positive cooperativity -till all bonded (plateau)
47
What is the Bohr effect?
*At high partial pressure of CO₂ *Haemoglobin gives up O₂ more easily
48
When is the Bohr effect important?
*In Active tissue, high partial pressure CO2- haemoglobin gives O2 easier *In lungs, where CO2 is low, reverse- O2 binds to haemoglobin easier.
49
How does Fetal blood become oxygenated?
*Oxygenated blood from mother runs close to deoxygenated from placenta *Fetal blood haemoglobin has high O2 affinity *Removes O2 moving past
50
What are the percentages in transport of CO2 (Tissues to lungs)
*5% dissolved in blood plasma *10-20%- CO2 binds with amino acids in haemoglobin (4, carbaminohaemoglobin *70-80% turns CO2 into bicarbonate ions,
51
when CO2 transported, describe the reaction of CO2 in bicarbonate.
*CO₂ + H₂O ⇋ H₂CO₃ ⇋ H⁺ + HCO₃⁻ *Reaction in red blood cells *Sped up by carbonic anhydrase *When HCO₃⁻ conc high, diffuses into plasma -Exchanged for Cl⁻ (chloride shift) to balance charge *Reaction maintains the pH of blood -When H⁺ low, equilibrium shifts right CO₂, H₂O made. *When CO₂ in the plasma, diffuses down partial pressure gradient to the alveoli
52
How is CO2 transported?
*5% dissolved in blood plasma *10-20%- CO2 binds with amino acids in haemoglobin (4, carbaminohaemoglobin, *70-80% turns CO2 into bicarbonate ions, which later becomes CO2 *Diffuse at alveoli down pressure grad
53
How is the heart adapted for circulation?
*Made of cardiac muscle, which is myogenic (doesn't fatigue automatically contracts/ relaxes *Contains coronary arteries that supply oxy blood for respiration. *Surrounded by pericardial membrane, prevents heart swelling with blood *Septum prevents oxy/deoxy mixing *L ventricle- thicker to pump at higher pressure around body, resistance of arteries *R ventricle- thinner cardiac muscle, only pumps to lungs *Artia thin, pump to ventricles
54
What is the function of the right side of the heart?
*Deoxygenated blood to the lungs
55
What is the function of the left side of the heart?
*Oxygenated blood to the body
56
How is deoxygenated blood pumped from the heart to the lungs?
*Atria /ventricular diastole *Deoxygenated blood enters vena cava to lower pressure -superior (upper body) -inferior (lower) -To right atrium *As blood enters, pressure increases -triscuspid valve opens -Artia contract -Blood flows to right ventricle *pressure increase, triscupid valve closes *Ventricle contracts -ventricle pressure increase, more than aorta * blood flows through semilunar valves (which close, no backflow) *Leave through right pulmonary artery goes to lung capillaries.
57
Why is the right ventricle thinner?
*Only pumps to the lungs, doesn't go as far *Doesn't need to overcome resistance of arteries *Blood must flow in lungs at low pressure to prevent capillary damage and allow gas exchange.
58
What do the tendinous cords do?
Prevent atrioventricular valves turning inside out in contractions
59
How is oxygenated blood pumped from the heart to the body?
*Arita and ventricular diastole (low pressure) *Blood enters pulmonary vein to left artium *Pressure increases -Bicuspid valve opens *atria contracts (systole) forces to ventricle *Ventricular pressure increases bicuspid valve closed *Left ventricle contracts, pumps through semilunar valves to aorta and around body
60
What is a septal defect?
*When the septum doesn't full develope after birth.
61
Why do fetus have a non-developed septum?
*Blood oxygenated in placenta not lungs *No pulmonary circuit needed *Blood in heart is all oxygenated
62
Describe the 2 types of valves.
*Atrioventricular- Artia to ventricles *Semilunar- Ventricles to arteries
63
what blood vessels carry deoxygenated blood
Veins- transport deoxygenated blood back to the heart Pulmonary Artery: deoxygenated blood from the heart to the lungs
64
What is the cardiac cycle?
the events of a single heartbeat
65
What is systole
heart muscle Contracting
66
What is diastole
Heart muscle relaxing
67
Describe the events of the cardiac cycle
*Diastole- Artia/ventricular muscles relax Passive filling -Increases volume in chambers -Pressure decreases blood flows in (passive filling) -Pressure increase opens atrioventricular valves *Artia Systole(contract) -Forces blood to ventricles -Pressure in ventricles increases -Atrioventricular valves shut (from pressure increasing at valve backs) *Ventricular systole -ventricles contract after pressure higher than atria -When pressure higher than aorta semilunar artery opens in aorta, leaves.
68
What is cardiac output?
heart rate x stroke volume
69
What is heart rate?
Beats of the heart per min
70
What is stroke volume?
Volume of blood leaving the heart each beat.
71
How is the cardiac cycle controlled?
*SAN releases wave of depolarisation across atria -Contracts *Wave reaches AVN, which releases another wave after a pause -Nonconductive tissue between atria and ventricle prevents reaching ventricle -Bundle of his conducts wave down septum and Purkinje fibres -To apex, contracts causing ventricle to contract -Cells depolarise (diastole) cardiac relaxes
72
What is wave of depolarisation
An electrical impulse
73
What and where is the SAN in the heart?
*Sino-atrial node -In upper wall of the right artium
74
What and where is the AVN in the heart?
Artio-ventricular node -in the septum
75
Why are impulses from AVN sent across the bundle of his?
*To bypass and cause a delay *Needs time for atria to pump all the blood into the ventricles before contracting
76
What is the normal heart rate?
60-100 bpm
77
What is bradycardia?
*Slow heart rate, less than 60bpm
78
When is bradycardia normal?
*Sleeping *Fit people have this, heart more efficient.
79
How is bradycardia treated?
*Artificial pace maker
80
What is tachycardia and when is it normal?
*Fast heart beat >100bmp *Normal in exercise, emotional situations, fever.
81
What is the treatment for tachycardia?
Medication/ surgery
82
What is atria Fibrillation
*Abnormal heart rhythm *Rapid atria depolarisation (contract very fast)
83
How is atria Fibrillation treated?
*Defibrillator, stops heart to heart myogenic rhythm
84
What is a Ectopic heartbeat
*Altered beat, Extra systole and longer pause after *Normal unless frequent.
85
What does an electrocardiogram measure?
*Depolarisation of the heart
86
Analyse a normal Electrocardiogram.
*Bump before peak -P-wave= Atrial depolarisation (systole) *Peak & dip before -QRS-complex= Ventricular depolarisation *Bump after peak -T-wave= Ventricular repolarisation (diastole)
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