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MBChB1 Phase 1 > Week 9 > Flashcards

Week 9 Flashcards

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1
Q

What is the circulatory system?

A

organ system transporting oxygen, carbon dioxide, nutrients etc

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2
Q

What is the cardiovascular system made up of?

A
  • heart
  • blood vessels aka arteries, veins, capillaries
  • blood
  • lymphatic system
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3
Q

what is the lymphatic system?

A

network of tissues, vessels and organs working together to move lymph back into circulatory system

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4
Q

what is the pulmonary circulation?

A

oxygen depleted blood passes from heart to lungs
returns oxygenated blood to heart

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5
Q

what is the systemic circulation?

A

oxygen rich blood passes from heart to lungs
returns deoxygenated blood to heart

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6
Q

what are the boundaries of the superior mediatinum?

A

T1
superior manubrium (chest wall)
sternal angle
T4/5

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7
Q

What is in the superior mediastinum?

A

thymus
aortic artery
pulmonary artery

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8
Q

what are the boundaries of the inferior mediastinum?

A

sternal angle
skeletal muscle of diaphragm

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9
Q

what is in the anterior portion of the inferior mediastinum?

A

fat and some thymus

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10
Q

what is in the middle portion of the inferior mediastinum?

A

heart

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11
Q

what is in the posterior portion of the inferior mediastinum?

A

aorta
oesophagus

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12
Q

function of trabeculae in heart?

A

increase flow and contractility of blood and heart

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13
Q

what is the endocardium?

A

the iner layer of the heart

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14
Q

2 layers of pericardium?

A

fibrous and serous

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15
Q

function of fibrous pericardium? problem with this?

A

tough outer layer anchoring heaart to diaphragm
prevents rapid overfilling of heart
can restrict if theres an accumulation of fluid aka pericardial effusion compressing the heart, especially in right side reducing cardiac output

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16
Q

function of serous pericardium? 2 layers?

A

helps lubricate heart
inner visceral and outer parietal

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17
Q

function of serous fluid?

A

reduces friction of layers during beating of heart

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18
Q

function of superior vena cava?

A

takes deoxygenated blood from head and neck and upper limbs to RA

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19
Q

function of inferior vena cava?

A

takes deoxygenated blood from below level of heart e.g. abdomen, pelvis, lower limbs to RA

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20
Q

pathway of blood from SVC and IVC?

A

Right atria then right ventricles, to pulmonary valve then pulmnary trunk then to lungs via pulmonary arteries

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21
Q

Where does oxygenated blood from lungs pass to?

A

pulmonary veins then to LA then mitral valve then LV then aorta then several other blood vessels

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22
Q

Function of coronary arteries?

A

first branch of aorta
pass blood to heart muscle

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23
Q

function of braciocephalic trunk?

A

passes blood to right subclavian artery and right carotid artery
first branch of aorta

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24
Q

function of right carotid artery?

A

supplies head and neck with blood

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25
function of right subclavian artery?
supplies right upper limb
26
function of ductus venosus? how much blood is taken to IVC here?
allows maetrnal blood to bypass fetal liver to go to IVC 30%
27
what does the ductus venosus become at birth?
ligamentum venosum
28
function of foramen ovale?
allows blood to flow between the right and left atrium
29
function of ductus arteriosus
links pulmonary trunk with aorta to allow blood to flow into systemic circulation of fetus prevents blood going to non breathing lungs in utero
30
function of umbiical arteries
carry deoxygenated blood back to placneta
31
what is 70% of maternal blood used in fetus?
liver
32
what is the fossa ovalis?
embryological remenant of forman ovale
33
function of aortic sinuses and location?
above aortic valve 3 of these, 2 from left and right coronary arteries give rise to coronary arteries
34
significance of right atrial appendage?
additional part of right atrium site for external pacemaker to be positioned
35
where is crista terminalis, function?
at opening of right atrial appendage site of origin for pectinate muscles
36
function of pentinate muscles?
allow strecth in RA and improve volume capacity
37
what is the orifice of the coronary sinus?
where venous blood from heart enters
38
function of pulmonary veins?
carry oxygenated blood to left atrium
39
which heart chamber is thicker?
left as it has to pump blood through systemic circulation
40
what are trabeculae carnae?
rounded muscular collumns in heart ventricles contraction pulls on chordae tendinae
41
what happens when you have atrial or ventricular septal defects?
present at birth holes between ventricles or atria small holes close themselfs compromise lungs and heart by increasing BP may require surgery
42
what are symptoms of atrio ventricular septal defect? requires?
breathing problems heart racing cyanosed tired easily surgery
43
which heart valve is tricuspid?
right between atria and ventricles
44
which heart vakve is bicuspid?
left between LA and LV
45
what are chordae tendinae?
heart strings connecting to papillary muscles prevent mitral and tricuspid valves flipping back into atria during ventricular contraction
46
WHat arteries supply heart muscle?
coronary arteries
47
Which coronary arteries does left coronary arteries give rise to?
circumflex artery anterior and posterior interventricular arteries
48
what arteries does right coronary artery give rise to?
marginal artery
49
name the cardiac veins?
small anterior cardiac veins small cardiac vein middle cardiac vein great cardiac vein
50
where do blood from the heart drain into right atrium?
coronary sinus
51
what are end arteries?
supply oxygenated blood to specific portion of tissue
52
where are end arteries found?
spleen liver intestines ends of digits ears nose penis
53
what happens if end arteries are blocked?
heart attack
54
what is ischaemia, what can it cause? what does it present with?
reduction in blood oxygen colateral circulation develops angina
55
what is colateral ciruclation?
new blood vessel growth to pass around area of reduced blood supply
56
what is infarction?
death of a tissue due to a lack of blood supply
57
which coronary arteries are usually affected by infarction?
anterior interventricular branch of LCA 40-50% RCA 30-40% circumflex branch of LCA 15-20%
58
what can be used in a coronary artery bypass graft?
saphenous vein (longest vein in body) internal mammary artery internal thoracic artery
59
what is the pacemaker of the heart? how? what does this mean?
sinoatrial node generates electrical signals controls heart rate
60
what is the moderator band of the heart?
allows more rapid contraction across to anterior papillary muscle helps with conduction times
61
what are purkinje fibres and their functions?
specialised conducting fibres create contraction across ventricles maintain regular heart rate
62
what is the pathway of nerve impulses in the heart?
pass from Sinoatrial node to atrioventricular node pass down interventricular septum through atrioventricular bundle through walls of left and right ventricles then into purkinje fibres
63
what makes up the upper respiratory tract?
nasal cavity pharynx larynx
64
what makes up the lower respiratory tract?
trachea primary bronchi lungs
65
functions of the respiratory tract?
conducts air (warms and humidifies) respiration (gas exchange) mucus protects against pathogens
66
what is the nasopharynx?
base of skull to soft palate
67
what is oropharynx?
soft palate to epiglottis
68
what is the laryngopharynx?
epiglottis to where bifurcation occurs to oesophagus and trachea
69
difference between right and left bronchus?
right - vertical, greater diameter and short so foreign body more likely to go here. Right has superior, middle and inferior lobe bronchus Left - has suberior and inferior lobe bronchus
70
what type of epithelia is respiratory epithelium?
pseudostratified ciliated columnar epithelium with goblet cells
71
what is lamina propira?
thin layer of connective tissue forming part of mucus membrane
72
function of brush cells in bronchi?
can detect bacteria proteins
73
what is different in each level of bronchi?
epithelium type
74
what happens in type I pneumocytes?
gas exchange
75
what is secreted by type II pneumocytes? function?
surfactant increases lung compliance/expandability and prevents atelectasis/collapse of lungs at end of expiration
76
when is surfactant produced?
weeks 24-28
77
how many lobes are in each lung?
left - 2 right - 3
78
what is contained in the hilum?
bronchus pulmonary arteries veins
79
what does the base of the lungs join with?
diaphragm
80
what does the costal urface of lungs connect to?
ribs
81
what 2 fissures exist in right lung?
horizontal fissure oblique fissure
82
what fissure exists in left lung?
oblique fissure
83
what 3 lobes are in right lung?
superior, middle, inferior lobe
84
what is a drug?
chemical entity altering body function prevents or treats disease
85
features of small molecule drugs?
synthetic and chemical derived low molecular weight simple structure stable cheap
86
how do drugs work?
drug must get to site of action bunds to target/receptor exhibits required response
87
what are biologics drugs? what disease are they involved in?
recombitant processes target soecific side effects expensive autoimmune disease
88
example of biologic drug and how it works?
etanercept recombitant antibody molecule blocks TNF alpha treats autoimmune disease
89
what is a drug target?
macromolecular component of a cell where a drug interacts to produce a response
90
what are drug targets usually and what do they change?
usually a protien change activity of cellular enzymes
91
what may happen to cellular enzymes when drug interacts with protein?
inhibited or activated
92
what siganl acts on ligand gated ion channels? where?
neurotransmitters in nerve or muscle cell
93
when is suxamethonium used and how..?
used in anaesthesia as a muscle relaxant binds to acethycholine receptor at neuromuscular junction depolarisation occurs
94
which molecule do catecholamines activate?
b adrenoreceptors activates adenylyl cyclase actuvates camp
95
what is bisoprolol used for? which type of drug id it? how does it work? speed?
heart conditions beta blocker blocks stimulation of b1 receptors , which would usually increase heart rate seconds to minutes
96
what are targets for peptide hormones in protein kinase inhibitors involved in? how long does this take...
cell growth and differentiatiin release of inflammatory mediators hours
97
where are cytosolic receptors foind? what do they do?
inside the cell regulate dna trabscription and protein synthesis hours to days
98
4 mechanisms of drug action?
ligand gated ion channels gpcrs protein kinase receptors cytosolic receptors
99
what is prednisolone used for? which type of drug is it?
allergies corticosteroid inhibits inflammation slow process
100
Role of the lungs?
Bring in oxygen rich air to the body Expel waste gas produced from cells in the body
101
What process is movement in and out the lungs coupled with?
Cellular respiration
102
Which type of homeostasis does breathing maintain?
Blood gas homeostasis
103
What is the partial pressure of oxyegn at rest?
100mm hg
104
What is the partial pressure of carbon dioxode at rest?
40mm Hg
105
How many liters of ventilation happens in the lungs at rest per minute, how many breaths?
6L/min 12 500ml/breath
106
How many mls carbon dioxide expired and oxygen consumer per minute?
250ml/min consumed 200ml/min expired
107
What is the barometric pressure?
Sea level atmospheric pressure 760 mmHg
108
How do you work out the partial pressure of a gas?
Fraction of gas in gas mixture x barometric pressure
109
What is the water vapour partial pressure at body temperature?
47mmHg
110
What is the partial pressure of oxygen in the trachea?
150mmHg
111
WhT is the primary muscle for respiration?
Diaphragm
112
What happens to the disphragm and exteranl intercostals in quiet breathing?
Inspiration: active Diaphragm contracts downwards and pishes abdominal contents outwards External intercostals pull ribs upwards and outwards Expiration: passive Elastic recoil
113
What happens in inspiration in strenuous breathinf?
Greater contraction of diaphragm (10cm compared to 1cm in quiet) and external intercostals Inspiratory accessory muscles active e.g. sternocleidomadtoud, alae nasi, genioglossus
114
What happens in expiration in strenuous breathing?
Abdominal muscles active Internal intercostals oppose external by pushing ribs down and inwards
115
What is pleural pressure?
Pressure between albeolar lining and chest wall
116
What is transpulmonary pressure?
Difference in pressure between pleural and alveolar pressure
117
What is alveolar pressure?
Pressure within alveolar sacs
118
What is the alveolar pressure at the start of inspiration?
The same as barometric pressure
119
What increases when inspiratory muscles contract? What decreases?
Thoracic volume Transpulomary pressure Alveolar volume pleural pressure decreases Alveolar pressure decreases below barometric pressure
120
Where does air flow into in inspiration? From which pressure?
Alveoli From high to low pressure
121
How does inspiration end?
Muscles stop contracting Thorax and alveoli stop expanding
122
What happens in expirstion?
Thoracic volume decreases Pleural pressure increases Transpulmonary pressure decreases Alveolar pressure becomes greater than barometric pressure
123
Function of the nasal cavities?
Filters warms and humidifies air Detects smells
124
Function of the pharynx?
Conducts air to larynx
125
Function of larynx?
Protects opening to trachea Contains vocal cords
126
Function of trachea? What jeeps the airway open?
Filters air Traps particles in mucus Cartilages keep airway ipen
127
Functions of bronchi?
Filters air Traps paritcles in mucus
128
Fucntion of alveoli?
Act as sites of gas exchange between air and blood
129
Function of upper airways?
Consucts air to lungs Humidifies air - saturates with water Warms to body temp Filter
130
How do upper airways filter air?
Inhaled particles stick to mucus Mucus move to mouth by beating cilia
131
Function of coughing?
Protective reflex gets rid if offending material
132
What receptors activate the cough reflex?
Rapidly adapting pulmonary strech receptors in epithelium of respiratory tract
133
What are RARs activated by?
Dust Smoke Amnonia Odeoma
134
What are RARs afferents of?
Vagus nerve
135
How is afferent information from RARs sent to brain?
Via vagus nerve
136
describe the cough reflex
- stimulation of rapidly adapting pulmonary strecth receptors by irratant e.g. dust - afferent information sent via vagus nerve to brain - brain sends information to diaphragm via phrenic nerve - external intercostals induce strong contraction - air rushes into lungs - abdominal muscles contract to induce expiration - glottis opens to forcefully expel air and irritants
137
what do trachea branch into? what happens with branching?
bronchi non respiratory brinchioles respiratory bronchioles alveolar ducts increase in number, decrease in diameter, increase in surface area
138
what are conducting airways ? where aree these? what do they form?
do not participate in gas exchange, only conduct air into body form anatomic dead space brinchi containing cartilage and non respiratory bronchioles
139
how much volume is in conducting airways?
150mls 30 percent of average breath
140
what are respiratory airways? where are they?
bronchioles with alveoli where gas exchange occurs from terminal bronchioles to alveoli
141
how long is the region of respiratory airways! how much volume is in these..
5mm long 2500ml volume
142
what is a respiratory unit? what does it consist of?
gas exchanging unit basic physiological unit of the lung consists of respiratory bronchioles, alveolar ducts, alveoli
143
how many alveolar sacs are in an adult?
300-400 million
144
what shape are alveoli? what is their dismeter?
250 microns
145
what type of cells are in alveoli?
type 1 and 2 epithelial cells
146
what are type one epithelial cells? how much surface area does this take up?
site of gas exchange in alveoli 97%
147
what are type 2 epithelial cells?
produce pulmonary surfactant to relieve surface tension
148
what are septal cells?
type 2 epithelial cells
149
what are alveolar macrophages?
remove debris
150
why are alveoli designed for gas exchange?
large surface area very thin walls good diffusion characteristics
151
surface area of alveoli?
100metres squared
152
how thin are alveolar walls?
0.5 microms
153
function of pulmonary circulation in lung?
brings deoxygenated blood from heart to lung and oxygenated blood from lung to heart
154
function of bronchial circulation in lung?
brings oxygenated blood to lung parenchyma
155
how much blood is in the pulmonary circulation?
500mls so 10 pervent
156
how much blood is in the alveolar capillary network at rest? what does this increase to and how?
75mls 150-200mls due to recruitment of new capillaries and increased pressure and flow in exercise
157
how long does it take for RBCs to pass through capillaries..
less than 1 second
158
what is the pulmonary circuit in gas exchange?
oxygen enters blood from alveoli down pressure gradient carbon dioxide leaves blood to alveoli down pressure gradient
159
what is the systemic circuit of gas exchange?
oxygen leaves blood to go to tissues down pressure gradient carbon dioxide enters blood via tissues down concentration gradient
160
what is partial pressure of oxygen in alveoli compared to venous blood?
alveoli - 100mmHg venous blood - 40 mmHg
161
what is the partial pressure of co2 in alveoli compared to venoud blood?
alveoli - 40mmHg venous blood - 46mmHg
162
what is the partial pressure of co2 in tissues compared to arterial blood?
tissue - 46mmHg arterial blood - 40mmHg
163
what is the partial pressure of oxygen in tissues compared to arterial blood?
tissues - 40mmHg arterial blood - 100mmHg
164
what processes near ro a cell can drugs act on?
inhibition/induction of transporter processes that carry substances in or out of cells incorporation into larger molecules altering metabolic processes unique to microorganisms e.g. penicillin
165
how can drugs act on processes outside a cell?
direct chenical interaction chealating agents
166
what are agonist drugs?
binds to receptor binding site activates it the same way as the endogenous chemical messenger would
167
2 types of agonist drugs?
full- an agonist with maximum efficacy partial - a drug with less than maximal efficacy
168
function of antagonist drugs?
interact with receptor but do not activate it affinity but no efficacy
169
example of partial agonist?
buprenorphine used to treat opiod addiction
170
2 types of antagonist drug?
competitive non competitive
171
what is a competitive antagonist?
competes with agonist for receptor reduces apparent affinity of the agoist
172
what happens to dose response curve in competitive antagonists?
dextral shift - displaced to the right loss of potency of agonist
173
what is a non competitive antagonist?
drug binds irreveribly to receptor producds slight dextral shift as more receptors are bound by non competitive agonists it is impossible for agonist to elicit maximum effect
174
what is affinity?
how strongly a drug binds to a receptor
175
what is efficacy?
a measure of the maximum biological effect resulting ffom a drug binding to its target
176
what is drug potency?
measure of the amount of drug required to produce a defined biological effect
177
example of drug potency?
morphine is more potent than aspirin less morphine is required to achieve a large analgesic effect than aspirin
178
what is a drug adverse affect?
response to a drug which is noixus and unintended occurs at normal doses used for therapy of a disease
179
how common are drug adverse effects? who is more at risk?
1 in 16 patients in hospital older adults and those on multiple prescribed medication
180
two types of drug adverse affects?
type a; related to intended pharmalogical action if the drug type b: effects unrelated to known pharmacological function
181
characteristics if type a drug adverse affect?
common predictable dose related usually usually not life threatening e.g. drug for lowering blood pressure may cause low blood pressure in patients
182
characteristics of type b adverse drug effects?
uncommon unpredicstbel usually not dose related usually life threatening e.g. severe allergy causing anaphyaltic shock afyer penicllim
183
what is theraputic efficacy?
capacity of a drug to produce an effect and refers to maximum such effect
184
what is median effective dose 50 ED50?
dose at which 50 percent of the population or sample manifests a given effect
185
what is median toxic dose 50 TD50?
dose at which 50 percent of population manifests given toxic effect
186
what is median lethal dose 50 LD50?
dose which kills 50 percent of subjects
187
what is drug toleramce? example?
continuous or repeated administration of a drug accompanied with gradual diminuation of the effect it produces must increase dose to get required effect of previous smaller dose
188
examples of drug tolerance?
alcohol - accellerated metabolism by enzyme induction opiates
189
3 concepts of drugs crossing the cell membrane?
phsiochemical properties of the drug properties of membrane type of transport
190
3 phsiochemical properties of drugs?
molecular size concentration gradient pharmacokinetics
191
properties of the cell membrane affecting drugs?
thickness surface area permability ph of cell
192
3 types of drug transport?
paracellular - diffuses through extracellular fluid diffusion through memrbanes active transport/transport protoens
193
2 types of diffusion across cell memrbaen for drugs?
passive and facilitated diffusion
194
3 types of passive diffusion?
paraceullar diffusion intracellular diffusion (lipid) membrane diffusion
195
2 types or faciliated diffusion?
channel protein carrier protein
196
what influences drug diffusion?
drug molecule size and shape concentration gradient membrane thickness membrane surface area pharmacokinetics ph of solution
197
3 time courses of drug effects
immediate delayed cumulative
198
example of delayed drug effect?
warfarin
199
what is warfarins drug action? effect? response?
inhibition of vit k recycling decreased synthesis of clotting factors prolonged cosgultion time
200
what is cumulation of a drug?
blood levels of a drug build ip and inreases its theraptuic and toxic effects
201
example of cumulative drug? action? effect? response?
omeprazole action - inhibits gastric acid pump effect - decreased acid secretion and increased pH response - ulcer healing
202
how exactly does omezaprole block proton pumps?
irreveribly binds to them
203
when do first order kinetics occur? what is the rate of elimination proportional to?
when a constant proportion of the drug is eliminated per unit time rate of elimination proportionsl to amount of drug in body - each half life of the drug halfs the concentration
204
how are most drugs eliminated?
first order kinetics every half life that passes eliminates half drug concentration
205
what are zero order kinetics? examples of drugs?
a constant amount of drug is eliminated per unit time e.g. 10mg drug eliminated per hour ethanol, phenytoin, salicylates
206
what are non linear kinetics due to?
saturation in a pharmacokinetic mechanism protein binding, hepatic metabolism, active renal transport of drug
207
what is theraputic drug minitoring?
monitors level of medication within blood
208
what is a loading dose? when is it used? what do you need to calculate this?
brings the concentration of a drug to the target range in a single dose used when rapid onset of action is needed volume of distribution
209
when is oral loading dose used?
when drug will take a long time to reach a steady state concentration e.g. digoxin
210
what are the functions of the cardiovascular system?
- transport of nutrients, oxygen, waste products around the body - transfer of heat (core to skin) - buffers body pH - transport of hormones e.g. adrenaline - asissts in infection response - assists in formation of urine
211
what is opening/closing of a valve determined by?
pressure gradients across the valve
212
what is calcification of valves? what can this cause?
calcium deposits form on aortic valve of heart causing narrowing of valve lv hypertrophy, heart failure
213
what is the first heart sound?
sound of AV valves closing
214
what is the second heart sound?
sound of pulmonary and aortic valves closing
215
why might a third heart sound be heard?
due to oscillation of blood flow into the ventricle
216
what is preload?
force from volume of blood present that stretches cardiac muscle prior to contraction
217
what is afterload?
the force the heart must work against to eject blood during contraction
218
what is end diastolic volume?
volume of blood left after ventricular contraction
219
what is stroke volme?
amount of blood ejected per beat
220
how is cardiac output calculated? average volume?
CO = SV x HR 5L / min
221
what determines heart rate in the heart? why?
sinoatrial node has fastest intrinsic rate
222
which part of the heart slows contraction and can act as a secondary pacemaker?
av node
223
what is excitation contraction coupling?
purkinje fibres interdigitate with myocyte to spread impulse across ventricles
224
what can problems with pacemakr cells cause?
arythmias tachycardia brachycardia
225
what does an ecg detect?
phasic change in potential difference between 2 electrodes
226
where are 2 electrodes placed in ecg? what is the role of the body in this?
on surface of heart on limbs volume conductor
227
what device is used in an ecg?
oscilloscope
228
what is the p wave in ecg?
atrial depolarisation
229
what is the qrs complex in an ecg?
ventricular depolarisation
230
what happens in the t wave in ecg?
ventricular repolarisation
231
what happens in pr interval of ecg?
delay through av node
232
what happens in st interval of ecg?
plateau phase of ap
233
what triggers action potential in sinoatrial node? what causes deplarisation? what causes repolarisation?
calcium ions in and reduced potassium ions out (both positive) calcium in potassium leaves and calcium channels closed
234
what happens if potassium permability increases in the sinoatrial node?
more potassium leaves so there is a longer time to thereshold therefore fewer bpm so HR decreases due to ach from vagal nerve
235
what happens in calcium permeability increases in the sinoatrial node?
shorter time to thereshold so more bpm so HR increases due to noradrenaline
236
what is the resting membrane potential in purkinje fibres?
-90mV
237
how is a purkinje action potential caused?
positive sodium moves in calcium ions move in potassium moves out
238
why is there a plateau phase in purkinje action potential? what is this on an ECG?
positive calcium is moving in but positive potassium is moving out at the same time ST segment
239
why is plateau phase of AP important?
elongastes phase of action potential by creating a refractory period this allows the heart to relax
240
what triggers contraction in cardiac muscle?
calcium entry
241
where does calcium come from to trigger contraction in muscles?
outside of myocyte sarcoplasmic reticulum inside cell
242
function of calcium induced calcium release in myocytes?
allows greater contraction for a small calcium movement acts as amplifier
243
how do some drugs increase heart contraction?
increase intracellular calcium
244
what is starlings law?
force of contraction increases as muscle was streched in response to increased filling of heart chambers otherwise circulation would fail
245
where are b1 adrenoreceptors found in the heart?
nodal tissue conducting system myocardium
246
what do b1 adrenoreceptors bind?
noradrenaline by sympathetic nerves adrenaline in circulation
247
effects of b1 adrenoreceptors binding adrenaline/noradrenaline?
positive inotropy positive chronotropy positive lusitropy positve dromotropy
248
what is positive inotropy?
increases contraction of the heart
249
what is positive chronotropy?
increases heart rate
250
what is positive lusitropy?
relaxing the heart muscle
251
what is positive dromotropy?
increases rate of conduction
252
effect of beta agonists on the heart?
bind to beta adrenoreceptors support with cardiogenic shock/arrest
253
what happens if you use a drug for asthma that acts on b1 and b2 agonists?`
causes inotropy etc causing increased HR/contraction/conduction
254
where does the left and right vagus nerve terminate?
R - SA node L - AV node
255
how does ACh released by vagus nerve affect m2 receptors?
activates them to reduce HR by increased K+ permeability
256
what do vagolytic drugs (inhibits vagal nerve activity) do in bradycardic patients?
increase heart rate
257
how can you stimulate the vagal reflex?
breath holding
258
what are changes in cardiac output detected by? where is this information taken to?
baroreceptors brain
259
arteries function?
carries oxygenated blood away from the heart around the body
260
function of arterioles?
small blood vessel branching off arteries which link to capillaries
261
function of capillaries?
gas exchange
262
function of venules?
drains blood from capillaries into veins
263
function of veins?
blood vessel carrying deoxygenated blood back to heart
264
where do endothelial cells line?
all vessels and inside of heart chambers
265
how are endothelial cells important to heart function?
regulates blood pressure prevents platelet aggregation and formation of blood clots angiogenesis +vessel remodelling can express molecules which tether inflammatory cells
266
what barrier do endothelial cells form?
permeability barrier for nutrients/fluid between plasma and interstitial fluid
267
what do endothelial cells release?
vasoconstrictors: endothelin, thromboxane vasodilators: nitric oxide, prostacyclin free radicals
268
function of free radicals?
oxidise ldl cholestrol
269
where is vascular smooth muscle found?
all vessels apart from smallest capillaries
270
function of vascular smooth muscke? what does it secrete? what happens when it multiplies?
determines vessel radius by contracting/relaxing secretes ecm to give vessels elastic properties hypertension
271
why is arterial elasticity (compliance) important?
allows large arteries to act as pressure reservoir prevents pressure falling to 0 as blood leaves arteries in diastole allows expansion of arteries without having pressure too high
272
why does calcification occur in arteries? what happens?
healing response to precense of dead cells reduces elasticity of vessel affects blood prssure more likely for plaques to form
273
when does blood pressure fall?
blood circulating from left to right ventricle in systemic circulation right to left in pulmonary
274
what is the normal blood pressure?
120/80 systolic/diastolic
275
how is mean arterial pressure caculated?
diastolic bp + 1/3 pulse pressure or co x tpr
276
what is the mean arterial pressure?
average pressure pushing blood round the system
277
where does blood to the arteries come from?
ventricles forcefully
278
what happens to arteries walls and why?
elastic wall stretched by raised pressure
279
how do aorta/arteries structures relate to their function?
small amount of blood at high pressure very thick walled/elastic
280
how do arterioles structures relate to their function?
variable resistance system distributing blood dissipates most of pressure
281
how do capillaries structures relate to their function?
interchange of substances with extracellular fluid of tissues large surface area, one cell thick
282
how do venules/veins/vena cava structures relate to their function?
contains most of blood at low pressure very distensible
283
how much blood is in capillaries?
5%
284
why are capilaries one cell thick?
rapid exchange with tissues
285
what does flow in capillaries depend on?
supply from arterioles
286
what is hydrostatic pressure?what movement does this pressure favour?
blood in capillaries exerts pressure on capillary wall movement out of the capillary
287
what is colloid pressure? what movement does this pressure favour?
plasma has instrinsic osmostic pressure due to plasma proteins movement of fluid into the capillary
288
hydrostatic pressure at arterial end of capillary opposed to venous end?
35mmHg at arterial 15mmHg at venous
289
what prevents pulmonary oedema?
pulmonary hydrostatic pressure much lower than systemic pressure
290
what pressure increases in heart failure? where does this happen in particular? symptoms?
capillary hydrostatic pressure increases in extremities pitting oedema, pulmonary oedema
291
what is pulmonary oedema caused by?
high altitude left heart failure
292
what symptoms happens in right heart failure?
jugular distension
293
what drugs reduce capillary hydrostatic pressure?
nitrates ace inhibitors vaso dilators
294
what is the net filtration of tissue fluid a day?
4 litres not including kidneys
295
what does build up of fluid in tissues cause? how does the body stop this?
oedema moves fluid back into blood with lymph vessels and capillaries
296
how do lymph vessels aid movement of fluid?
contraction
297
where is the carina found in the lungs?
where the trachea bifurcates
298
which parts of the lung are especially sensitive to irratants and create a cough?
larynx and carina
299
what are the main arterial baroreceptors in the body detecting changes in blood vessels
carotid sinus aortic arch
300
how do nasal hair protect against infection?
trap foreign particles
301
how can you change total peripheral resistance to lower blood pressure?
- nerve varicosities from sympathetic nervous system release noradrenaline - activates alpha 1 adrenoreceptors on blood vessels - blood vessels constrict - tpr raised and raises bp
302
name a selective alpha adrenoreceptor antagonist? what is its function?
prazosin, doxazosin decreases total peripheral resistance
303
name a non selective alpha adrenoreceptor antagonist? why are they not used theraputically?
phentalomine blocks a1 and a2 adrenoreceptors a2 adrenoreceptors act as negative feedback to prevent excessive noradrenaline release more noradrenaline is released when a2 adrenoreceptor bound to so more competition for a1 receptor
304
how does prazosin work?
blocks a1 adrenoreceptor reduces noradrenaline binding reduces constriction of blood vessels total peripheral resistance decreases
305
how do nasal decongestants work?
vasoconstrict mucosal blood vessels by releasing endogenous noradrenaline
306
which channel does menthol cool and act as a local anasthetic?
TRPM8
307
what can dilate arterioles? what happens?
changes in o2/co2/cellular metabolites active hyperaemia
308
what is reactive hyperaemia induced by?
blocking blood flow temporarily
309
how is flow maintained? what is this?
flow autoregulation blood flow in vascular bed reamins constant during varied arterial arterial pressure
310
what can reduced blood flow cause?
coronary artery disease = MI critical limb ischaemia reynaud's
311
what are factors controlling blood flow?
length of tube viscosity of liquid aka blood pressure gradient across tube cross sectional area of tube
312
what is assumed about flow?
flow is laminar flow is non pulsatile flow is through a uniform straight pipe
313
what problems can be caused by viscosity of blood?
- deep vein thrombosis - immobility due to venous pooling - dehydration increases blood viscosity so flow increases
314
how to decrease thickened blood viscosity?
movement increases venous return hydration reduce alcohol compression socks for dvt
315
how is flow determinded?
pressure gradient resistance
316
what is resistance proportional to?
diameter
317
what happens as branching increases down the arterial tree (arteries, arterioles, capillaries)?
resistance increases flow reduced
318
function of valves in veins?
prevents backflow of blood
319
what happens when theres too much blood in the veins?
increases capillary hydrostatic pressure increases fluid in tissue oedema
320
how does skeletal muscle aid in venous return?
in exercise it compresses veins moves venous blood back to heart acts as a pump
321
what 3 things aid venous return?
skeletal muscle pump respiratory muscle contraction sympathetic nerves
322
how do sympathetic nerves aid in venous return?
noradrenaline constricts veins increased bp increases venpus return to heart
323
what is preload? what happens if it increases?
venous return to the right ventricle heart has to work harder to pump blood out - probem in heart failure and coronary artery disease
324
what does cerebral dilation by glyceral nitrate cause?
headache
325
effect of nitrates on the circulatory system?
primary venodilation reduces preload on the heart so reduces cardiac work
326
what does venodilation do to the cardiovascular system?
decreases central venous pressure precreases preload decreases cardiac outpit decreases cardiac work/oxygen consumption
327
what is reflex tachycardia and what is it caused by? what does this maintain?
blood pressure decrease causes chronotropy maintains arterial blood pressure
328
where does aortic arch baroreceptors take information?
brain via vagus nerve 10
329
where does carotid sinus take information to the brain?
nerve IX
330
which baroreceptor is most sensitive? when?
carotid receptor so more importnat most sensitive around mean arterial pressure
331
where do baroreceptors inpit information?
nts - nucleus tractus solaris
332
which pressure is baroreceptors sensitive to?
60-180mmHg
333
what does decreased arterial pressure do in baroreceptors, parasympathetic and sympathetic systems?
decreased arterial baroreceptors firing decreased parasympathetic outflow to heart so heart rate increases increased sympathetic outflow to heart, arterioles veins to increase HR
334
which reflex decreases parasympathetic outflow to heart?
medullary cardiovascular centre
335
how is blood pressure lowered by the nucleus tractus solaris?
alpha 2 adrenoreceptor inhibits bulbar circulatory centres to lower noradrenaline release to decrease tpr activates vagus nerve to release ach to lower cardiac input
336
how is blood pressure increased by the nucleus tractus solaris?
beta 1 adrenoreceptor activates bulbar circulatory centres to release noradrenaline to increase tpr inhibits vagal nerve releasing ach to increase cardiac output
337
function of clonidine? problem?
alpha 2 agonist decreases blood pressure activates presynaptic receptors in brain vasomotor centres to lower sympathetic output rebound hypertension
338
function of methyldopa? problem? when is it used?
used as central a2 adrenoreceptor agonist decreases bp decreases dopamine used in hypertension in pregnancy
339
what is local control of bp?
modulation of local blood pressure/flow and can override central control systems independent of nerves/hormones
340
what is involved in the local control of bp?
metabolites blood gases endothelium derived factors
341
how does nicorandil treat angina?
opens potassium channels hyperpolarises smooth muscles closes calcium channels reduces muscle contraction

MBChB1 Phase 1 (12 decks)

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