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Structure And Function Of Living Organisms > Circulatory system > Flashcards

Circulatory system Flashcards

1
Q

What are the functions of the circulatory system

A

distribution of nutrients, support for metabolism (O2 delivery), distribution of water and electrolytes, transportation and distribution of hormones

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2
Q

What are the principle components of a circulatory system

A

Fluid that circulates through the system, mechanism that applies force to drive the fluid, system of tubes for the fluid to pass through, valves or septa to ensure unidirectional flow

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3
Q

Open circulatory system

A

incomplete system of vessels. Contains a circulating fluid called haemolymph which flows through vessels and freely percolates through intracellular spaces. Bathes internal organs and therefore directly reaches every cell of the body

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4
Q

Open circulation in insects

A

Use tracheal system to transport nutrients and CO2. Circulation can be less efficient when respiratory gases are handled through a separate system

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5
Q

Features of a closed system

A

complete and continuous system of blood vessels, blood, heart propels blood through vessels, intercellular spaces filled with interstitial fluid. Lymph in lymphatic vessels

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6
Q

Where does diffusion occur in the circulatory system

A

between blood vessels and interstitial fluid at the capillary bed

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7
Q

Requirements of an efficient circulatory system

A

Efficient O2 carriers in blood or haemolymph, efficient gas exchange and delivery of nutrients, diversification of oxygenated fluid to systemic organs and deoxygenated fluids to respiratory organs, fast flow of fluids

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8
Q

Flow rate formula

A

change in pressure/ resistance

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9
Q

pressure and resistance in a closed circulatory system

A

high change in pressure and high resistance

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10
Q

pressure and resistance in an open circulatory system

A

change in pressure is low and resistance is low

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11
Q

Functions of the mammalian cardiovascular system

A

distribution of O2 and nutrients, transportation of CO2 and removal of metabolic waste, distribution of water, electrolytes and hormones, thermoregulation, immune system infrastructure

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12
Q

arrangement of the mammalian cardiovascular system

A

4 chambered heart (unidirectional flow), blood supplies to systemic vascular bed run in parallel, pulmonary circulation runs in series, high pressure system

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13
Q

Components of a blood vessel

A

endothelium, smooth muscle, connective tissue

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14
Q

Function of the endothelium

A

lining of blood vessels, lines entire cardiovascular system, keeps blood in system, allows transfer between vessels and surroundings

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15
Q

where does the blood stream exchange things

A

through tissue fluid and endothelial cells. Junctional complex

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16
Q

Cycle of the circulatory system

A

heart, elastic arteries, muscular arteries, arterioles, capillaries, venuoles, veins, nheart

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17
Q

Elastic arteries function

A

smoothing. Catch blood that comes out of the heart and when the heart ventricle pumps it produces a burst of very high-pressure blood into the elastic arteries which expand, increasing their volume and reducing the pressure, when blood moves back out, elastic arteries shrink back in and increase the pressure again

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18
Q

Muscular arteries function

A

can be big and decrease in size as they get longer, muscles contract to control the diameter

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19
Q

arteriole function

A

controls blood flow to the capillaries at sufficient pressure

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20
Q

Capillary function

A

gas exchange. Thin and delicate

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21
Q

Venule function

A

Can exchange fluid with surroundings

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22
Q

General structure of blood vessels (except capillaries and sinusoids)

A

tunica intima (endothelium+CT), tunica media (smooth muscle + CT), tunica adventitia (CT), internal elastic lamina (IEL), extrernal elastic lamina (boundaries of t.media)

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23
Q

What is the arrangement of smooth muscle

A

long and thin, circular (controls diameter), narrow, small muscular artery + vein

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24
Q

Elastic arteries: aorta, pulmonary artery

A

very big lumen, thick walls, smooth muscle cells are contractile, elastic fibres organised into sheets, parallel to one another and run around the vessel, arranged concentrically and circular lumen, collagen to resist tension,

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25
Blood supplies to large arteries
thick walls of busy, living vells that requiire gases, vessels above certain sizes have their own circulation in walls, walls too thick to receive adequate O2 nutrient supply and waste disposal from centre
26
What are muscular arteries lined with
endothelium
27
Arteriole structure
same structure as larger vessels. Thicker wall and smaller lumen
28
Capillary network
terminal arterioles that control blood flow to the capillary bed. Pressure must be enough to get blood flow but not too much to burst capillaries. Sinusoid - one cell thick
29
Continuous endothelium
sit on top of basement membrane, all sit in complete layer, found in most layers and exchange solutes and gases
30
Fenestrated endothelium
cells have pores between them, sit on top of intact basement membrane, found in capillaries in endocrine glands, exchange larger molecules (hormones)
31
Discontinuous endothelium
gaps between cells, gaps in basal lamina, cells don't fit properly together, found in sinusoids, exchange whole cells, leaking tissue fluid
32
Venules and veins
thinner wall and larger lumen, bigger than capillaries, liquid exchange between plasma and tissue fluid, difference between venules and veins is the tunica media (vein is smaller), substantial T. adventita. Arterial pulse massages blood along vein, increases pressure in the veins. Muscle contraction squeezes and moves blood through valves
33
Valves
Folds of tunica intima (one way flow), valves point to the heart, pocket shaped structure
34
Blood (haemolymph) pressure
Difference between the pressure in the system and the ambient pressure (transmural pressure)
35
What are the 2 components of blood pressure
dynamic pressure (produced by the pump) and hydrostatic pressure of the fluid
36
What does the resistance of the system equal
sum of individual resistances of all elements
37
What can decrease resistance of the system
decreasing the number of resistors and adding more conductors
38
Artery function
conduit for blood to capillary beds, act as pressure resevoir to drive blood into arteries, damp oscillations in pressure and flow, control differential distribution to different organs and tissues
39
Veins functions
conduit for blood to return to heart, act as blood resercoir, flow influenced by external factors
40
Blood vessels providing resistance
as vessel diameter increases, blood flow decreases. Constriction of arterioles increases resistance.
41
Where is the site of greatest resistance
arterioles - they can change size of lumen. Blood enters arterioles with high speed and as the blood exits the pressure and speed is greatly reduced
42
What can cause a change in smooth muscle tone
neurotransmitters, hormones, endothelium derived substances, metabolites, pressure, heat
43
How do arteries regulate and distribute blood flow
change in smooth muscle tone - vasoconstriction and vasodilation
44
Arteriole pulse pressure
top number (systolic) - the bottom number (diastolic)
45
Total fluid energy
potential energy acquired from the beating of the heart, kinetic energy of the fluid itself, potential energy of the fluid that it possessed because of its position in the gravitational field, the fluid flows from where its total fluid energy is higher to where its total fluid energy is lower
46
What does pressure increase in proportion to
the height of the colum
47
Affect of height above the heart
arterial pressure decreases, acting against gravity
48
Affect of height below the heart
increase arterial pressure
49
Why does blood pool in lower limbs when stood upright
venous return is reduced, leads to a decrease in cardiac stroke volume, lower arterial blood pressure, immediate decrease in blood flow to brain
50
Vasoconstriction and vasodilation in a giraffe
when stood upright gravity causes vasoconstrcition (prevents blood pressure from falling) of vessels in lower body. When it lowers its neck the aortic pressure decreases causing vasodilation of vessels in lower body
51
Define cardiac output
the total volume of blood pumped by the heart in one minute
52
cardiac output (L/min) formula
heart rate (beats/min) x stroke volume (L/beat)
53
What does the P wave show
electrical activity in the right atria (depolarisation)
54
What does the QRS complex show
depolarisation of the ventricles
55
What does the T wave show
repolarisation of the ventricles
56
What does the PR interval show
conduction through AV node
57
What does the QT duration show
ventricular depolarisation and repolarisation
58
What is the heart rate modified by
autonomic nervous system (parasympathetic and sympathetic) and circulating hormones
59
What does the parasympathetic and sympathetic nervous system do to heart rate
Parasympathetic - slows Sympathetic - increases
60
Calcium's role in muscle contraction
binds to myofilaments in order to contract
61
How is electrical activity coordinated
contraction is highly organised, atria contracts followed by ventricles, relaxation is also coordinated to allow filling
62
How do valves ensure one way flow of blood
atria contract and eject blood into relaxed ventricles, AV valves close as ventricle contracts. Aortic and pulmonary valves open to allow blood out of ventricle
63
What is systole
contraction of chambers and ejection of blood
64
What is diastole
relaxation and filling
65
What is troke volume modified by
intrinsic control (degree of stretch of cardiac muscle - starlings law) and extrinsic control (sympathetic stimulation - modulation of Ca availability)
66
Where is the heart located
In the chest cavity, behind sternum. Centre/left. Top of diaphragm between the lungs in mediastinum. Bulges into the left lung so left lung is smaller than right.
67
What keeps the heart into position
by the pericardium and large blood vessels entering and leaving
68
Serous pericardium function
lines inside of the fibrous pericardium. Secretes a watery fluid between its layers allowing free movement
69
What does the visceral layer line
is attached and lines the heart
70
What does the parietal layer line
fibrous pericardium
71
Function of the fibrous pericardium
prevents over expansion of the heart
72
Coronary arteries
fewer interconnections (anastomoses). Easily blocked = heart attack. Coronary artery bypass surgery - graft leg veins to bypass blocked cpranry arteries
73
Internal anatomy of the heart
muscular septum divides into left and right halves. Atrium and ventricle on each side. All chambers lined by smooth lining (endocardium)
74
Anatomy of the right atrium
thin walled. Receives blood from superior vena cava (blood from head, arms and thorax), inferior vena cava (lower body), coronary sinus (heart walls)
75
Anatomy of right ventricle
thick walled. Recieves blood from the atrium. Pumps into pulmonary trunk and legs.
76
Where is the tricuspid valve located
Right atrium and right ventricle
77
Where are the semilunar valves located
between ventricle and pulmonary trunk
78
Where are the bicuspid valves located
left atrium and left ventricle
79
Anatomy of the left atrium
thin walled, receives 2 pulmonary veins from each lung. Foramen oval
80
Anatomy of the left ventricle
very thick wall. Blood from atrium. Blood to aorta
81
What is the foramen ovale
a flap between the right and left atria. The foetus gets nutrients by O2/CO2 exchange across the placenta, so most blood bypasses the lungs using the foramen ovale. Another route is ductus arteriosus between pulmonary trunk and aorta
82
What happens to the foramen ovale and the ductus after the baby is born
the foramen seals permanently. (hole in the heart is when it doesnt seal). Ductus goes into spasm and closes (fuses shut and becomes fibrous tissue)
83
Atrioventricular valve function
prevent ventricle to atrium flow when ventricles contract
84
Function of the valve between the right atrium and coronary sinus
stops back flow of blood into coronary veins when atrium contracts
85
chorda tedinae function
maintain the position and tension of the atrioventricular valves
86
papillary muscle function
helping to prevent leakage through the AV valves during systole
87
What is the myocardium
Muscle layer
88
What is the epicardium
visceral pericardium
89
Describe the endocardium
lining of the heart. Appears rigid (trabeculae carnae) - underlying bundles of muscle fibres. Made up of endothelium and underlying connective tissue
90
What makes up the myocardium
cardiac muscle fibers and connective tissue
91
What links cells together end to end
intercalated discs, allows cells to branch and join with other fibers
92
What are intercalated discs
3 types of cell-cell junctions link the heart muscle cells
93
What do adherent junctions link
actin cytoskeleton (sarcomere contractions)
94
What do desmosomes link
intermediate filaments - strength
95
What do gap junctions link
cytosol and allow cell-cell comms coordinate contraction cell to cell along the heart muscle fibres

Structure And Function Of Living Organisms (10 decks)

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