circulation Flashcards
1
Q
in multicellular animals are all cells engaged in metabolic activities
A
yes
2
Q
every cell requires nutrients but which cells require oxygen
A
only those that carry out aerobic respiration
3
Q
what are examples of cell waste products
A
nitrogenous compounds and carbon dioxide
4
Q
why must every cell be bathed in aqueous solution
A
to allow for diffusion
5
Q
what is diffusion proportional to
A
the square of distance
6
Q
what is diffusion
A
the passive process of molecules moving from a high concentration to a low concentration over a semi permeable membrane
7
Q
in terms o diffusion why do we need a complex transport system
A
diffusion alone is far too slow
8
Q
diffusion plays an important role in movement of materials over what distance
A
<100um
9
Q
do protistan, cnidarian and platyhelminthes require a complex transport system
A
no diffusion is sufficient because they are either small, thin or flat
10
Q
What is the main purpose of the circulatory systems
A
to transport nutrients and oxygen to the tissues and remove waste products
11
Q
what is a small artery called
A
arteriole
12
Q
what is a small vein called
A
venule
13
Q
do vertebrates have a closed or open circulatory system
A
closed
14
Q
what does the circulatory system of vertebrates include
A
heart
arteries
veins
capillaries
15
Q
do veins and arteries travel side by side
A
yes
16
Q
how many chamber are in the heart
A
4 - 2 atria and 2 ventricles
17
Q
which artery is the only one to carry deoxygenated blood
A
pulmonary artery
18
Q
what direction do arteries travel
A
away from the heart
19
Q
what direction do veins travel in
A
towards the heart
20
Q
describe the circulatory system of a fish
A
single circulation
one atrium, one ventricle
blood reaches the tissues after passing over the gills to collect oxygen
blood has low pressure when flowing in the systemic part
21
Q
what about the fish is in series
A
the gills and the systemic capillaries (tissues)
22
Q
why is the fish circulatory system adequate
A
they have low metabolic rate as they are ectotherms
23
Q
describe the circulatory system of amphibians
A
a partial double circulation
limited mixing
can redirect blood from the lungs to the skin - less blood goes to the lungs when the animal is not moving
24
Q
as well as using the respiratory system how else do frogs respire
A
through their skin when they are in water
25
describe the circulatory system of reptiles
one ventricle partly divided by a septum
R-L shut occurs when submerged so blood by-passes the lungs
2 atria
26
in vertebrates which ventricle is thicker
the left ventricle
27
what are the pacemakers of the heart
the SA node primarily and the AV node is involved
28
How does the SA node set the pace of the heart
it sends out an electrical charge at a specific interval. this causes the right atrium to contract starting the whole string of events that gets blood pumping in waves through your body.
29
where do the SA and AV nodes sit in the heart
the right atrium
30
what is a pacemaker
it is a small device inserted into the chest of a recipient that mimics the electrical impulses of the SA and AV nodes
31
where is the pulmonary semilunar valve found
Between the right ventricle and the pulmonary artery
32
where is the aortic semilunar valve found
Between the left ventricle and the aorta
33
where is the tricuspid (atrioventricular) valve found
the right atrium
34
where is the bicuspid (atrioventricular) valve found
the left atrium
35
what process quickly follows the failure of the circulatory system
brain death - 3-4mins later
36
on average how many time does the heart beat per minute
70
37
how many times does an elephant heart beat per minute
25
38
how many times does a shrew heart beat per minute
25
39
what is the effect of mammal size on metabolic rate
smaller the mammal, greater the metabolic rate (due partly to their increased surface area to volume ratio)
40
the smaller the animal the …………. the heart rate
faster
41
life span ……………. with an decrease in heart rate
increases
42
what is the phrase that means the heart contracts spontaneously
myogenic property
43
what are the intercalated discs of the cardiac muscle
channels connecting cells
44
what occurs via the intercalated discs
cell-cell transmission
45
what is the rhythm of the cardiac muscle in the ventricles
slow
46
what is the rhythm of the cardiac muscle in the atria
faster than ventricles
47
what is the rhythm of the cardiac muscle in the SA (sino-atrial) node
the fastest - faster than atria and ventricles
48
describe what happens when the heart contracts
heartbeat is initiated by the SA node
it spreads over the atria
then it spreads over the ventricles
49
Excitation spreads slowly from the SA node over the atria to the AV node. why is this process slow
to ensure that atrial contraction is complete before ventricular contraction begins
50
cell-cell transmission is adequate for what size of heart
small
51
what is the order of excitation
SA Node > AV Node > Bundle of His > Purkinje Fibres
52
instead of cell-cell transmission what do larger hearts require
bundle of his and purkinje fibres which conduct rapidly to all parts of the ventricles including the apex (bottom tip of the heart in the left ventricle)
53
what is the bundle of his
a collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node to the point of the apex of the fascicular branches via the bundle branches.
54
what leads from the bundle of his to the purkinje fibres
fascicular branches
55
what happens when excitation reaches the purkinje fibres
electrical conduction to the ventricles, causing the cardiac muscle of the ventricles to contract at a paced interval.
56
what results when purkinje fibres become damaged
ventricular fibrillation - use a defibrillator to restart.
57
what regulates the frequency and strength of the heartbeat
autonomic nervous system - the part of the nervous system that controls things automatically
58
what does the sympathetic nervous system do
excitation of the heart
increase in heart rate
increase in stroke volume (greater force of contraction
59
what does the parasympathetic nervous system do
inhibition of heart
decrease in heart rate
decrease in stroke volume (weaker force of contraction)
60
what is stroke volume
the volume of blood pumped from the left ventricle per beat
61
what is epinephrine
adrenaline
62
what does excretion of epinephrine result in
increases heart rate and stroke volume
63
what is the stroke volume at rest
70ml/beat
| 5litres/min
64
what is the heart rate at rest
70beats/min
65
what is the heart rate during strenuous exercise
up to 180bpm
66
what is the stroke volume during strenuous exercise
25 litres/min
| up to 35 litres/ min in a athlete
67
what happens to blood flow during exercise
cardiac output blood flow increases
brain blood flow is constant
skeletal muscle blood flow is increased
alimentary system blood flow is decreased
68
why shouldn't you exercise straight after a meal
the blood flow of the alimentary system is decreased as the blood is diverted to the skeletal muscles and cardiac output so food won't be digested as efficiently
69
what is systole
when the ventricle (left in example but can be either) contracts, blood is forced under high pressure into the aorta and blood surges forward in all arteries. the pressure waves stretch the walls of the arteries. this is a pulse
70
what is diastole
when the ventricle relaxes, the pressure falls and the elastic of the stretched arteries recoils, maintaining some pressure in the blood
71
what determines blood pressure
cardiac output and peripheral resistance met by the blood as it passes from the arteries into the arterioles and capillaries.
72
what is peripheral resistance
resistance to flow determined by the diameter of the tube – the smaller the diameter the greater the resistance
73
what is the cardiac cycle in terms of systole and diastole
atrial and ventricular diastole
atrial systole, ventricular diastole
ventricular systole, atrial diastole
74
what is the first sound of the heart beat
LUB
75
what is the second sound of the heart beat
DUB
76
which valves are open during atrial and ventricular diastole
atrioventricular valves (tricuspid and bicuspid (mitral) valves)
77
which valves are closed during atrial and ventricular diastole
semilunar valves (aortic and pulmonary valves)
78
what is the pulse pressure calculation
systolic-diastolic pressure difference
79
is there a pulse in veins
no
80
what are the 4 main functions of arteries
1. To transport blood from the heart to the capillaries
2. To act as pressure reservoir for forcing blood into small diameter capillaries – their thick walls withstand pressure
3. To dampen oscillations in pressure and flow generated in the heart, so producing a more even flow of blood to the capillaries.
4. The arterioles control flow to the capillary beds
81
what is vasoconstriction
smooth muscle in the arteriole wall contracts to decrease blood flow to capillary bed
82
what is vasodilation
smooth muscle in the arteriole wall relaxes to increase blood flow to capillary bed
83
what is vascular tone
the degree of constriction experienced by a blood vessel relative to its fully dilated state.
84
what controls the flow of blood between arterioles and venules
precapillary sphincters - rings of smooth muscle
85
what ultimately controls blood flow to the capillary beds
the sympathetic nervous system, hormones and local factors
86
is blood flow constant
yes
87
which organ have their capillaries filled to capacity
heart, brain, kidneys and liver
88
where is blood diverted to when body temperature increases
the skin - vasodilation occurs
89
what are the main functions of veins
1. To transport blood from capillaries back to the heart
| 2. To act as a storage reservoir for blood (60% of blood volume is in veins).
90
blood pressure is very low in the veins, so how is blood returned to the heart?
They return blood to the heart by the mechanism of having valves (blood may only flow in 1D) and skeletal muscular activity.
91
what is thrombophlebitis
the pooling of blood, leading to blood clot formation in bedridden patients - why people are encouraged to walk soon after operation
92
what increases the likelihood deep vein thrombosis (blood clot in the leg)
Immobility for long periods of time e.g. long flight
93
what is thrombosis
formation of a blood clot or thrombus in a blood vessel.
94
where can a blood clot block a vessel
in the vessel in which it forms or it may become dislodged and be carried to some other location in the circulatory system, in which case it is called an embolus. can be very dangerous e.g. in the lung
95
what is a stroke
When an embolus or thrombus blocks a blood vessel in the brain
96
what are symptoms of a stroke
depending on which part of the brain has been damaged (due to lack of blood supply) – e.g. paralysis, speech impairment, emotional disturbance.
97
where do capillaries run from
arterioles to venules
98
what are endothelial cells
Endothelial cells are the thin layer of cells that line the interior surface of all blood vessels. these cells line the entire circulatory system
99
what are the 2 ways that materials can move in and out of capillaries
passively and actively
100
how do materials move in/out capillaries passively
through capillary endothelial cell wall
| e.g. O2, CO2
101
How do materials move in/out capillaries actively
```
by bulk flow through the intercellular spaces between the endothelial cells. happens in most capillaries (not the brain)
active transport (especially in brain) there are tight junctions in the brain that close the intercellular spaces forming a blood brain barrier
```
102
how do nutrients get from capillaries to cell tissues
the nutrients diffuse into the interstitial fluid around the cells
103
define cardiac output
the volume of blood each ventricle pumps per minute
104
define heart rate
number of beats per minute
105
define stroke volume
the volume of blood pumped by a ventricle in a single contraction
106
what creates the lub sound
recoil of blood against the closed AV valves
107
what creates the dub sound
the closing of the semilunar valves
108
what happens when impulses are released from the SA node
both atria contract in unison
the impulse reaches the AV node
signals from the AV node a re conducted to the heart apex and throughout the ventricular walls by bundle of his branches and purkinje fibres
109
which two systems regulate the pacemaker function of the SA node
the sympathetic and parasympathetic nervous system
110
which nervous system speeds up the pacemaker when you walk
sympathetic
111
which nervous system slows down the pacemaker when you sit down
parasympathetic
112
which gland secretes epinephrine that induces fight or flight (speeds up the pacemaker)
adrenal glands
113
what else other than the sympathetic and parasympathetic nervous system affects the pacemaker
body temperature - increase in temperature increases heart rate
114
what is a heart murmur
when blood squirts back through a defective valve
115
what is a an endothelium
single layer of flattened epithelial cells
116
what part of the blood vessel is lined with an endothelium
the central lumen (cavity)
117
how does endothelium affect resistance
it decreases the resistance
118
what surrounds the endothelium in a capillary
basal lamina
119
what layers surround the endothelium of arteries and veins
smooth muscle and connective tissue (elastin allow stretch and collagen allows strength)
120
why can arteries accommodate blood pumped at high pressure
because they have thick walls
121
what controls modulation of blood flow by constriction or dilation
signals from the nervous system and circulating hormones act on the smooth muscle of the vessels
122
do veins contain valves
yes
123
do arteries contain valves
no
124
what happens to the velocity of blood flow when blood flows between the arteries and arterioles
decreases
125
what is the connection between total cross sectional area and velocity of blood flow
increase in cross sectional area = decrease in blood flow velocity
126
Blood, like all fluids flows from areas of …………….pressure to areas of ………..pressure
higher to lower
127
contraction of a …………… generates blood pressure
ventricle
128
when is arterial blood pressure highest
when the heart contracts during ventricular systole
129
what is the blood pressure called when the heart contracts
systolic pressure
130
what is the blood pressure called during diastole
diastolic pressure
131
why is blood always under pressure
so that their is a continuous flow
132
how is a continuous flow of blood maintained
during diastole, before enough blood has flowed into the arterioles to completely relieve pressure in the arteries, the heart contracts again (systole)
133
Smooth muscles of the arteriole wall contracts. vasoconstriction …………….. blood pressure upstream in the arteries
increase
134
smooth muscles of the arteriole walls relax. vasodilation ………………. blood pressure in the arteries
decrease
135
how is blood pressure measured
systole pressure/diastole pressure (mm Hg)
136
what is osmotic pressure
the pressure produced by the difference in solute concentration across a membrane
137
the difference in osmotic pressure between the blood and the interstitial fluid ………….. fluid movement out of the capillaries
opposes
138
generally, blood pressure is …………. than opposing forces leading to net loss of fluid from the capillaries
greater
139
how is the fluid lost from the capillaries brought back to the blood
via the lymphatic system
140
what is the fluid recovered to the lymphatic system called
lymph
141
do lymph vessels have valves
yes
142
disruption in the movement of lymph can result in fluid accumulation in affected tissues. what is this called
edema
143
edema is responsible for what in starving children
bloated bellies (kwashiorkor)
144
Pregnant women get swollen ankles because their …….…….…. pressures become higher than the norm.
osmotic
145
by what method of transport does gas exchange occur
by diffusion
146
what factors does rate of transfer depend upon
area
distance
concentration difference
147
area should be as large/small as possible
| diffusion distance should be as small/large as possible
large
| small
148
describe the anatomy of the lungs
trachea, bronchus, bronchioles, alveoli
149
what hormone secreted by the kidneys stimulates generation of erythrocytes
erythropoietin
150
what is coagulation
liquid blood going to solid blood
151
the enzyme thrombin converts what to what
fibrinogen to fibrin - this forms a clot
152
what is a heart attack caused by
a blockage in one of the coronary arteries
153
what is partial pressure
the pressure exerted by a particular gas in a mixture of gases
154
in what direction does a gas move
from a high partial pressure to a lower partial pressure
155
what makes an alveoli
capillary endothelium
interstitial space
alveolar epithelium
156
what about alveoli maximises gas exchange
moist walls
thin walls
large surface area
157
what are the walls lined with
moist epithelium cells
158
what are the lungs
localised respiratory organs
159
run through the process of breathing
inhale through nostrils
air goes to pharynx
trachea opens and air passes through into bronchi then bronchioles then alveolidissol
160
what lines the epithelium that line the major branches in the lung tree
cilia
161
what do cilia do in the lungs
they brush up mucous into the pharynx where it is swallowed into the oesophagus
162
where does gas exchange in mammals occur
alveoili
163
how is oxygen taken up
oxygen in the air entering the alveoili dissolves in the moist film lining their inner surfaces and rapidly diffuses across the epithelium into a web of capillaries that surrounds each alveoli
164
how is carbon dioxide removed from the capillaries
net diffusion of carbon dioxide occurs from the capillaries across the epithelium of the alveoli and into the air space
165
As the oxygen passes through the airways it .........….pressure.
loses
166
mammals employ negative/positive pressure breathing
negative - it means pulling rather than pushing air into the lungs
167
air pressure is lowered by muscle contraction which expands the thoracic cavity, causing what
influx of air into the lungs
168
inhalation
The diaphragm ..............and is pulled down
The rib cage expands and the rib muscles contract
contracts
169
exhalation
rib cage gets ……………
rib muscles ………..
elasticity of lungs drives air out of them
smaller
| relax
170
what is tidal volume
volume of air inhaled and exhaled with each breath
171
what is vital capacity
tidal volume during maximal inhalation and exhalation
172
what is residual volume
air that remains after a forced exhalation
173
because the lungs of mammals don't completely empty with each breath fresh and oxygen depleted residual air mix slightly. what results
concentration of oxygen in alveoili is always less than in the atmosphere
174
how is CO2 transported
5% as dissolved CO2
5% attached to haemoglobin and other blood proteins
90% as bicarbonate ions
175
describe cooperativity of haemoglobin
when one oxygen binds affinity of other sites increases
| when one oxygen is released affinity of other sites decreased
176
where is the foramen Ovale located (allows blood to bypass the lungs)
between the right and left atrium
177
what coats the lining of the alveoli
pulmonary surfactant
