cardiovascular system Flashcards
(316 cards)
1
Q
what is the heart and what does it do?
A
- self adjusting double pump
- propels blood around 2 circulatory systems
2
Q
what 2 systems does the heart pump blood around?
A
pulmonary and systemic
3
Q
what is the heart formed from?
A
- myocardium (specialised cardiac muscle)
4
Q
what does myocardium contraction allow?
A
- blood to be pushed out the chambers
5
Q
what does myocardium relaxation allow?
A
- blood to flow or be pushed into heart
6
Q
what is contraction of ventricles known as?
A
systole
7
Q
what is relaxation of ventricles known as?
A
diastole
8
Q
why is pulmonary circulation pumped at low pressure?
A
- not much force required to send blood distance through lungs from right to left heart
- high pressure would force fluid out into blood - lead to drowning
9
Q
what are the properties of the blood pumped from lungs to right ventricle?
A
- very low oxygen concentration
10
Q
where does blood go after leaving right ventricle?
A
- through pulmonary trunk which divides to give left and right pulmonary arteries
11
Q
what does systemic mean?
A
affects whole body
12
Q
where does the systemic circulation feed in to?
A
- in and out all organs apart from the lungs
13
Q
what is the origin of systemic circulation?
A
left ventricle
14
Q
where does the systemic circulation terminate?
A
right atrium
15
Q
what type of pressure does systemic circulation operate at?
A
- high pressure
- force needed to perfuse all tissues
- blood has larger distance to travel from left to right heart
16
Q
is the supply to organs rich or poor in oxygen?
A
rich
17
Q
is the blood supply returning to the heart rich or poor in oxygen?
A
poor
18
Q
where does the thorax lay?
A
sits superiorly in trunk of body
19
Q
what is the function of the thoracic cage?
A
- protects contents of thorax
20
Q
what is thoracic cage made up of?
A
ribs, costal cartilage, sternum (anteriorly), thoracic vertebrae (posterior)
21
Q
what are the components of the thoracic cage?
A
- superior and inferior thoracic aperture
- sternum
- costal cartilage
- ribs
- thoracic vertebrae
22
Q
what are the 3 regions of the thoracic cavity?
A
- mediastinum
- left pleural cavity
- right pleural cavity
23
Q
what is the mediastinum?
A
- central compartment of thoracic cavity
- situated between lungs
24
Q
what is mediastinum superior to?
A
superior thoracic aperture
25
what is mediastinum inferior to?
diaphragm
26
what is mediastinum anterior to?
sternum and costal cartilages
27
what is the mediastinum posterior to?
thoracic vertebrae
28
what does the mediastinum consist of?
- hollow visceral structures joined by loose connective tissue
29
what is the sternal angle?
- the joint between the manubrium (top) and the body (middle) of sternum
30
where is the thoracic plane 'drawn'?
horizontal plane drawn from sternal anal to level between T4 and T5
31
what 2 compartments does the thoracic plane split the mediastinum into?
- superior mediastinum
- inferior mediastinum
32
what is the inferior mediastinum further divided into?
- anterior
- middle
- posterior
33
drawings
34
what features does the superior mediastinum contain?
- oesophagus
- trachea
- neurovasculature: arch of aorta, superior vena cava, phrenic nerves, vagus nerves, thoracic duct, sympathetic chains
35
what features does the anterior mediastinum contain?
- mainly consists of fat and the thymus
36
what does the middle mediastinum contain?
- contains the heart and pericardium
- contains root of great vessels, phrenic nerves, vagus nerves
36
what does the posterior mediastinum contain?
- descending aorta and branches
- oesophagus
- thoracic duct
- azygos system of veins
- sympathetic chains
37
what structure features in both inferior and superior mediastinum?
oesophagus
38
what is the azygos system of veins?
- H shaped configuration of the azygos, hemiazygos and accessory hemiazygos veins
- drains the posterior thoracic wall
39
what are the sympathetic chains?
- external to spinal column
- adjacent to vertebral bodies
- paired structure (one on each side of body)
- also known as sympathetic trunk
40
what is the thoracic duct?
- main lymphatic vessel for return of chyle/lymph to systemic venous system
- drains lymph from both lower limbs, abdomen, left hemithorax, left upper limb, left side of face and neck
41
what is the thymus?
- T cell producing lymphoid organ
- plays role in development of immune system (maturation of T cells)
42
what is the phrenic nerve?
- paired nerve
- supplies the diaphragm
- comes from nerve roots C3. 4 and 5
43
what is the vagus nerve?
- tenth cranial nerve (CNX)
- paired
- provides bulk of parasympathetic input to gastrointestinal system and heart
- complex mixed sensory, motor and parasympathetic nerve
44
what is the pericardium?
membrane that covers the heart
45
where is the pericardium positioned?
within the middle mediastinum of the thorax
46
what 2 layers does the pericardium consist of?
- outer fibrous layer
- inner thin serous layer
47
what is the structure of the fibrous/outer layer?
- continuous with great vessels adventitia (aorta and pulmonary trunk)
- blended inferiorly with central tendon of diaphragm
- rigid structure
48
what is the structure of the serous pericardium?
- contained within the fibrous pericardial sac
- analogous to the pleural membrane
- double layer
- lubricating fluid between layers to reduce friction caused by heart contraction
49
what are the two layers of the serous pericardium?
- visceral layer (epicardium) -> inner layer of serous pericardium
- parietal layer -> outer layer that lines the fibrous pericardium
50
what are the 4 functions of the pericardium?
1. protection from infection
2. fixes the heart in the mediastinum and limits its motion
3. lubrication
4. prevents rapid overfilling of the heart
51
how does the pericardium protect the body from infection?
- fibrous later serves as physical barrier between muscular body of heart and adjacent organs prone to disease
52
how does the pericardium fix the heart in position?
- its attached to the diaphragm, sternum and outer layer of great vessels to fix heart in place
53
how does the pericardium allow lubrication?
- serous pericardium and small amount of serous fluid within pericardial cavity reduces friction between heart and surrounding structures
54
how does the pericardium prevent rapid overfilling of the heart?
- fibrous layer of pericardium prevents heart from increasing in size too rapidly
- places physical limit on potential organ size
55
what is cardiac tamponade?
- where blood or fluid accumulates the pericardium
- causes compression of the heart, preventing the ventricles from expanding fully and impeding its blood supply
- potentially fatal
56
what is cardiac tamponade a result of?
- pericarditis caused by either a bacterial or viral infection
- trauma where damage to heart/vessels causes pericardium to fill with blood
- end stage lung cancer, heart surgery, dissecting aortic aneurysm
57
what is the treatment of cardiac tamponade?
- immediate hospitalisation where pericardiocentesis is performed where fluid is drained from pericardium to reduce pressure
58
define pericarditis
inflammation of pericardium
59
how does dissection of aortic aneurysm occur?
- when tear occurs in inner layer of bodys main artery
- blood rushes through tear causing inner and middle layers of aorta to split
60
what is acute myocardial infarction?
- life threatening condition that occurs when blood flow to the heart muscle is abruptly cut off (heart attack)
61
what is pericardiocentesis?
- a procedure done to remove fluid that has built up in the sac around the heart (pericardium)
- done using needle and small catheter to drain excess fluid
62
what are the great vessels of the right side of the heart?
- superior vena cava
- inferior vena cava
- pulmonary tank
63
what is the function of the superior vena cava?
- brings deoxygenated blood to right atrium from systemic circulation superior to heart
64
what is the function of the inferior vena cava?
- brings deoxygenated blood to right atrium from systemic circulation inferior to the heart
65
what is the function of the pulmonary trunk?
- exits the right ventricle
- takes deoxygenated blood to the lungs
- bifurcates into right and left pulmonary arteries
66
what are the great vessels of the left side of the heart?
- pulmonary veins
- aorta
67
what is the function of the pulmonary veins?
- they enter the left atrium on posterior aspect of heart
- carry oxygenated blood from pulmonary circulation
68
what are the 4 pulmonary veins?
- left superior and left inferior
- right superior and right inferior
69
what is the function of the aorta?
- leaves the heart
- carries high pressure
- carries oxygenated blood to the body in systemic circulation
70
what forms the anterior (sternocostal) surface?
- formed mostly from the right ventricles
- surface is related anteriorly to sternum and ribs
71
what forms the inferior (diaphragmatic) surface?
- mostly the left ventricle, partly from the right ventricle
- related inferiorly to centre of diaphragm
72
what forms the left (pulmonary) surface?
- mostly by the left ventricle
- related laterally with left lung
- occupies a depression in lung known as cardiac impression
73
where is the base of the heart located?
- on the posterior aspect
- directed towards vertebrae T6-9
74
what forms the base of the heart?
- from left and right atrium
- extends from bifurcation of pulmonary trunk superiorly to atrioventricular groove (depression between atrium and ventricle on each side of heart) inferiorly
75
where does the apex of the heart lie?
- posterior to 5th intercostal space in midclavicular line
- directed antero-inferiorly and to the left
76
what are the 4 borders of the heart?
- right
- inferior
- left
- superior
77
what is the right border formed by?
- right atrium
- extends from superior to inferior vena cava
78
what is the inferior border formed by?
- roughly horizontal
- formed mostly by the right ventricle
-small contribution by left ventricle
79
what is the left border formed by?
- left ventricle
- superior portion formed by auricular appendage of left atrium
80
what is the superior border formed by?
- both atria
- aorta and pulmonary trunk arise from this border
81
where does superior vena cava enter heart?
- right side of superior border
82
what is the sternal angle?
- joint between manibrium of the sternum and the sternal body
82
what is the position of the superior border of the heart?
- reaches third costal cartilage on right side of sternum
- and second intercostal space on left side of sternum
83
what is the position of the right margin of the heart?
- extends from right third costal cartilage to near the right sixth costal cartilage
84
what is the position of the left margin of the heart?
- descends lateral from the second intercostal space to the apex
- located near the midclavicular line in 5th intercostal space
85
what is the position of the lower margin of the heart?
- extends from sternal end of right 6th costal cartilage to apex in 5th intercostal space
86
what are the different layers of the heart?
- epicardium
- myocardium
- endocardium
87
what does the epicardium consist of?
- layer of connective tissue
- provides protective layer over the heart
88
what does the myocardium consist of?
- myocytes or cardiac muscle cells
- muscular component of heart wall
89
what does the endocardium consist of?
- epithelium and connective tissue fibres that line heart and cover heart valves
- continuous with endothelial lining of blood vessels
90
what are the features of cardiac muscle?
- straited muscle
- not under voluntary control
91
what does cardiac muscle contraction rely on?
- sliding filament mechanism between thick and thin muscle filaments of sarcomeres
92
what is the difference between cardiac and skeletal muscle?
- cardiac muscle cells = highly branched, interconnecting network of fibres
93
why are cardiac muscle cells interconnected?
- allows heart to operate as functional syncytium
- whole heart contracts when one part is electrically stimulated
94
what physically divides the cardiac cells?
- sarcolemma (around fibrils)
- intercalated discs (between the cells)
95
what do intercalated discs separate?
- sarcoplasm of adjacent cardiac muscle cells
96
what allows the discs to be held together?
- action of desmosomes
97
what are desmosomes?
- specialised structure of cell membrane that allows adhesion to anchor neighbouring cells together
98
what do intercalated discs allow to pass through?
- electrical excitation between the cells through gap junctions
99
what is the fibrous skeleton of the heart?
- where the cardiac muscle is anchored to for support
100
what is the fibrous skeleton made up of?
- dense collagen (network forms 4 fibrous rings to surround valve openings)
- 2 fibrous trigones (triangles that lie between rings)
- provides membranous parts of interatrial and inter ventricular septa
101
what is the purpose of the fibrous skeleton?
- prevents valve openings from collapsing or distending
- provides base for attachment for leaflets and cusps of valves
- forms electrical barrier between atria and ventricles preventing contraction together
102
what are the 4 chambers of the heart?
- right atrium
- right ventricle
- left atrium
- left ventricle
103
where do the atria lie?
- superior to the ventricles
- separated by intertribal septum
104
what does the right atrium fill with?
- deoxygenated blood from systemic circulation
105
what does the left atrium fill with?
- oxygenated blood from pulmonary circulation
106
where does blood move once in atria?
to the ventricles
107
which ventricle is more muscular and why?
- left
- has to pump blood around whole body
108
what divides the ventricles?
- inter ventricular septum
109
what are the atria?
- thin walled chambers that receive blood from circulatory system
110
which circulation drains into left atrium?
- pulmonary circulation
- through pulmonary veins
111
where does the systemic circulation drain into?
- right atrium
- through superior and inferior vena cava
112
is ventricular filling active or passive?
- passive
- because atria don't contract until the end of diastole
113
what is essential during exercise?
- line up of atrial contraction and speed up of ventricular filling
- allows increased rate of ventricular contraction
114
what are the features of the right atrium?
- atrioventricular orifice (right)
- atrioventricular node
- crista terminalis
- fossa ovalis
- interatrial septum
- opening of coronary sinus
- pectinate muscles
- right auricle
- sinoatrial node
- sulcus terminalis
115
what is the atrioventricular orifice (right)?
- the aperture in which blood flows from the right atrium to the right ventricle
- where the tricuspid valve is positioned
116
what is the atrioventricular node?
- the electrical relay station between the atria and ventricles
- located in the posteroinferior region of the interatrial septum near the opening of the coronary sinus
117
what is crista terminalis?
- means terminal crest
- the origin of the pectinate muscles
- the sulcus terminalis (on the external surface) acts as a surface marking for the internal crista terminalis
118
what is the fossa ovalis?
- embryological remnant of the foramen ovale (hole between the 2 atria in a foetal heart)
119
what is the interatrial septum?
- the fibromuscular wall between the left and right atrium
- where the fossa ovalis and AV node is located
120
what is the opening of the coronary sinus?
- the main cardiac vein
- where the deoxygenated blood drained from the heart returns to the heart's circulation
121
what are the pectinate muscles?
- meaning comb like
- parallel ridges in the wall of the atrium
122
what is the right auricle?
- also known as right atrial appendage
- muscular pouch the acts to increase capacity of atrium
123
what is the sinoatrial node?
- pacemaker of heart
- located in posterior wall of right atrium
- inferolateral to opening of superior vena cava
-along superior part of crista terminalis
124
what is the sulcus terminalis?
- shallow depression marking point of fusion between venous part of right atrium and true right atrium
- crista terminalis sits on internal surface of this structure
125
what are the features of the right atrium?
- atrioventricular orifice (right)
- fossa ovalis
- interatrial septum
- left auricle
- pectinate muscles
126
what is the left auricle?
- known as left atrial appendage
- muscular pouch that acts to increase capacity of atrium
127
what are the pectinate muscles?
- comb like
- parallel ridges in wall of atrium
- sparse in left atrium
128
what are the ventricles?
- thick walled muscular chambers which propel blood around pulmonary and systemic circulation
129
which ventricle is more muscular?
left
130
why is this side more muscular?
more force is required to create higher pressure needed for tissue perfusion in systemic circulation
131
how are the muscle fibres arranged in ventricles?
- so ventricular contraction progresses upwards in spiral from apex of heart
- towards vessels leading out the ventricles
132
what are the papillary muscles extensions of?
- muscle of ventricular wall in left and right ventricles
133
where are the papillary muscles attached?
- to mitral and tricuspid valves via inextensible papillary tendons (chordae tendineae)
134
what occurs to papillary muscles during systole?
- they contract and prevent valves from inverting as result of high pressures created in contracting ventricle
135
what does back flow of blood cause?
- damage to atria wall and valves
- would reduce efficiency of ventricular contraction in pumping blood into pulmonary and systemic circulations
136
what are the features of the right ventricle?
- atrioventricular orifice (right)
- atrioventricular valve (tricuspid)
- chordae tendineae
- conus arteriosus
- interventricular groove
- interventricular septum
- moderator band
- papillary muscles
- pulmonary valve
- trabeculae carneae
137
what is the atrioventricular orifice?
- aperture in which blood flows from right atrium to right ventricle
- tricuspid valve positioned here
138
what is the atrioventricular valve (tricuspid)?
- valve sitting in atrioventricular orifice
- has 3 cusps
- prevent reflux of blood into right atrium
139
what is the chordae tendineae?
- meaning tendinous cords
- heart strings
- attach to cusps of atrioventricular valves and to the papillary muscles of ventricle
- act to hold valves in place and prevent reflux
140
what is the conus arteriosus?
- anterosuperior region of right ventricle from which the pulmonary trunk arises
141
what is the inter ventricular groove?
- the groove or sulcus on external surface of heart
- demarks the division between the two ventricles
142
what is the inter ventricular septum?
- fibromuscular wall between right and left ventricles
143
what is the moderator band?
- thick muscular structure that arises from the interventricular septum and ends at right anterior papillary muscle
- acts as shortcut for electric impulses from right bundle tract
144
what are the papillary muscles?
- nipple like
- muscles extend from ventricular walls
- attached to chordae tendineae
- contract and pull on these chords which prevent prolapse of atrioventricular valve cusps
- in right ventricle there are anterior, posterior and septal papillary muscles
145
what is the pulmonary valve?
- semilunar valve between the right ventricle and pulmonary trunk
146
what is the trabeculae carneae?
- meaning meaty ridges
- irregular muscles columns found on internal surface of ventricles
147
what are the features of the left ventricle?
- aortic valve
- atrioventricular orifice (left)
- atrioventricular valve (bicuspid/mitral)
- chordae tendineae
- inter ventricular groove
- inter ventricular septum
- papillary muscles
- trabeculae carneae
148
what is the aortic valve?
- semilunar valve between left ventricle and aorta
149
what is the atrioventricular orifice (left)?
- aperture in which blood flows from left atrium to left ventricle
- where bicuspid (mitral) valve is positioned
150
what is the atrioventricular valve (bicuspid/mitral)?
- has two cusps
- prevent reflux of blood into left atrium
151
what would happen without heart valves?
- contraction of wall surrounding ventricles would send blood forwards to pulmonary artery and backwards into aorta
152
what are atrioventricular valves?
- between atria and ventricles (prevent back flow of blood during systole)
153
what do the AV valves consist of?
- leaf shaped cusps
154
what does increased pressure in ventricles cause?
- cusps to form tight seal together in systole
155
what do the papillary muscles and chordae tendineae ensure?
- proper closure of valves and prevents inversion of blood
156
what are the semilunar valves?
- valves between ventricles and great vessels
- prevent back flow of blood during diastole
157
where dow the aortic valve exist between?
- left ventricle and aorta
158
what does the semi lunar valve consist of?
- three cusps shaped like pockets
159
what are aortic sinuses?
- spaces behind the aortic valves
160
what does the lub heart sound correspond to?
closure of atrioventricular valves
161
what does the dub heart sound correspond to?
closure of semilunar valves
162
???? heart sound stuff
163
what does abnormal heart sounds detect?
- something wrong with valves
164
what is a heart murmur caused by?
- blood leaking through incompletely closed or excessively narrowed (stenosed) valve
165
how does the blood flood occur through systemic and pulmonary circulation?
1. deoxygenated blood from inferior and superior travels through superior vena cava
???? look at slides
166
what does the cardiac cycle refer to?
- pattern of contraction and relaxation of heart during one complete heartbeat
167
what is contraction of heart known as?
systole
168
what is relaxation of heart known as?
diastole
169
what does contraction take place due to?
- intrinsic conducting system within the heart
170
what is the intrinsic conducting system?
- made up of specialised cardiac muscle cells
- they initiate a heartbeat
- contraction of cardiac muscle pumps blood through and out the heart
171
what is the extrinsic conducting system controlled by?
- nerves
- controls heart rate, contraction force etc.
172
what does the hearts electrical tissue consist of?
- two nodal tissues (sinoatrial node and atrioventricular node)
- conductive fibres
- myocardium
173
what is the sinoatrial node?
- pacemaker of heart
- its repeated automatic depolarisation sets the rhythm of the heartbeat
174
what is the structure of the SA node?
- cluster of cells
- situated on posterior wall of right atrium
175
what is the rate of SA firing modified by?
- autonomic input (sympathetic increasing heart rate, parasympathetic decreasing heart rate)
176
what happens once impulse reaches AV node?
- passes along main conductive bundle of His
- through insulating annulus fibrosus
- down inter ventricular septum of heart where it bifurcates into right and left bundle branches
177
what are the structures of the bundles now?
- narrow, slow conducting fibres
- terminate at extensive network of Purkinje fibres
178
what are Purkinje fibres?
- fast conducting fibres
- they spread impulse throughout ventricular myocardium
- causes upward wave of contraction
179
what is the purpose of the moderator band?
- in right ventricle
- provides shortcut for electric impulses of right bundle branch from inter ventricular septum to anterior papillary muscle of right ventricle
180
what is the process of movement to cause contraction after SA node depolarisation?
1. internal tract allows synchronised contraction of both atria and conduction to AV node
2. AV node receives impulse and transmits signal to ventricles via bundle of His
3. bundle of His transmits signal down inter ventricular septum, splits in two
4. left and right bundle branches transmit AP to Purkinje fibres
5. allows contraction from apex base of heart
180
what is an electrocardiogram?
- diagnostic tool
- measures electrical activity of the heart
181
what can you measure using ECG?
- activity and direction of electrical impulses in heart
182
what is the P wave?
- atrial depolarisation
183
what is the QRS complex?
- represents conduction of impulse through inter ventricular septum
- ventricular depolarisation
- atrial repolarisation
184
what does the T wave represent?
- ventricular depolarisation
- end of cardiac cycle
185
where do the coronary arteries arise?
- superior to the cusps of aortic valve
- from aortic sinuses
186
what are the 3 sinuses of the aortic valve?
- posterior aortic sinus
- left aortic sinus
- right aortic sinus
187
where does the right coronary sinus arise from?
- right aortic sinus
188
where does the left coronary artery arise from?
- left aortic sinus
189
where doesn't have an artery arise from?
- posterior aortic sinus
190
what does the left coronary artery supply?
- left atrium
- most of left ventricle
- some of right ventricle
- anterior part of inter-ventricular septum
- SA node
191
what does the left coronary artery divide into?
- anterior interventricular branch (left anterior descending branch)
-smaller circumflex branch
192
where does the anterior inter ventricular branch supply?
- anterior walls of both ventricles
- trails down anterior surface heart along inter ventricular groove towards apex of heart
193
where does the circumflex supply?
- supplies left ventricle
- supplies SA node in 40% of people
- passes along coronary (atrioventricular) groove on left border of heart to posterior surface
- gives off left marginal artery which runs on left border of heart
194
where does the right coronary artery supply?
- right atrium
- most of right ventricle
- some of left ventricle
- posterior IV septum
- SA node (in 60% of population)
195
what does the right coronary artery give off near its origin?
- ascending sinoatrial node branch that supplies SA node
196
where does the right coronary artery descend?
- in right atrioventricular groove
- gives off marginal branch at right margin of heart
- supplies right border of heart
197
what does the right coronary artery give off at the crux of the heart?
- large posterior inter ventricular branch
- descends in posterior inter ventricular groove
198
what is the crux of the heart?
- zone of junction of interartrial and inter ventricular septa, atrioventricular valves and 4 chambers of heart
199
what is venous drainage?
- network of cardiac veins drain deoxygenated blood from heart tissue and deposits in the coronary sinus
- this drains directly into right atrium
200
how is myocardial infarction caused?
- by blocked/severely restricted coronary artery
- myocardium becomes ischaemic
200
what is myocardial infarction?
- heart attack
201
what does ischaemic mean?
- deficient supply of blood due to obstruction of inflow of arterial blood
202
what does severe ischaemia lead to?
- tissue death due to lack of oxygen
202
what is the definition of infarct?
- area of tissue death due to local lack of oxygen
203
what is the most common location for ischaemia to occur?
- left anterior descending artery
204
what are the symptoms of myocardial infarction?
- chest pain
- nausea
- sweating
- jaw pain
- syncope (fainting)
- pressure in chest
- left arm or shoulder pain
- dyspnea (shortness of breath)
- neck pain
205
what are the ways of diagnosing myocardial infarction?
- ECG (reviews electrical activity)
- blood test (looks for markers of heart muscle damage)
- imaging (assess structure and function of heart)
206
what is the treatment of myocardial infarction?
1. primary percutaneous intervention (PCI)
2. thromolytics / fibrinolytics
3. coronary artery bypass graft
207
what is primary percutaneous intervention (PCI)?
- angioplasty (widen the blocked vessel using a stent)
- blocked vessel accessed through artery in groin
208
what is thrombolytics / fibrinolytic?
- medicines used to break down blood clots
209
what is the coronary bypass graft?
- blood vessel from elsewhere in body is attached above or below blockage
- blood can divert around blocked artery
210
what is the cardiovascular system made up of?
- heart
- blood vessels
- blood
211
what is the pulmonary circulation?
- deoxygenated blood travels through pulmonary arteries to the lungs
- oxygenated blood returns to heart through pulmonary veins
212
what is the systemic circulation?
- oxygenated blood travels through arteries to peripheral structures to supply with nutrients
- venous (deoxygenated) blood returns to heart
213
what is the vascular system talking about?
- blood vessels of the human body
214
what is the structure of the vascular system?
- great vessels emerging from heart split into smaller arteries
- they branch to form arterioles
- they branch into lots of capillaries
- capillaries converge to form venules
- venues converge to form veins
215
what are arterioles?
- narrow high resistance vessels
- diameter of 0.1 - 0.5 mm
216
what are capillaries?
- site of diffusion of nutrients and waste between blood and tissues
217
what are capillaries?
- thin walled
- oxygen and nutrients from blood enter organs and tissues
- take waste away from tissues
- oxygen exchanged for co2 and waste
218
what blood vessels have a three layered wall?
- arteries
- arterioles
- venules
-veins
219
what does the wall consist of?
- tunica intima (inner)
- tunica media (middle)
- tunica adventitia (outer)
220
what does the intima consist of?
- single sheet of endothelial cells resting on thin layer of connective tissue
- layer is mechanically weak but barrier to plasma proteins
- secretes vasoactive products
221
what does the media consist of?
- layer of smooth muscle of varying thickness
- matrix of elastin and collagen
- supplies mechanical strength, elasticity and contractile power to vessel
222
what does the adventitia consist of?
- connective tissue with no distinct outer border
- main role is to tether vessels loosely in place
- contains vasa vasorum in large arteries
223
what is the vasa vasorum?
- small blood vessel network
- responsible for nourishing the media
224
what else do larger vessels sometimes contain?
- nociceptive sensory fibres
- sympathetic nerve plexi
225
what are the different types of blood vessels?
- elastic arteries
- conduit (muscular) arteries
- arterioles
- capillaries
- arteriovenous anastomosis
- veins and venules
226
what are the characteristics of elastic arteries?
- diameter 1-2cm
- tunica media rich inelastic
- distensible walls
227
what happens to elastic artery walls in systole?
- expand to receive stroke volume of ventricular ejection
228
what happens to elastic artery walls in diastole?
- recoil
- creates almost constant flow in more distal tissues
229
what is the blood pressure created by elastic recoil called?
- diastolic blood pressure
230
what are the examples types elastic arteries?
- aorta
- pulmonary artery
- iliac arteries
231
what are the characteristics of conduit (muscular) arteries?
- diameter 0.1-1cm
- tunica media thicker relative to lumen of vessel
- media contains more smooth muscle (prevents collapse at sharp bends eg. elbow)
- highly innervated by autonomic nervous system (can contract/relax)
232
what is the main function of muscular arteries?
- limitation of blood loss in major trauma
233
what are examples of conduit (muscular) arteries?
- radial, cerebral and coronary arteries
234
what are the characteristics of arterioles?
- diameter <0.1 cm
- narrow lumen
- large numbers
- proximal and distal
235
what are proximal arteries?
- many smooth muscle layers
- richly innervated by sympathetic (vasoconstrictor) nerve fibres)
236
what are distal arterioles?
- closer to capillaries
- have 1-3 layers of smooth muscle
- poorly innervated by sympathetic fibres
237
what is the main function of arterioles?
- main site of blood flow regulation to tissues
238
what are the characteristics of capillaries?
- diameter 0.004-0.007cm
- wall contains single layer of endothelial cells
- very numerous
239
what is the blood pressure like at capillaries?
- very low
- slowest movement
- allows exchange of nutrients, gases and waste
240
what are the three different types of capillaries?
- continuous (intercellular cleft, basement membrane, endothelial layer)
- fenestrated (fenestrations)
- sinusoid (incomplete basement membrane, intracellular gap)
241
what are the characteristics of arteriovenous anastomosis?
- diameter 0.02-0.135cm
- only found in few tissues (skinned nasal mucosa)
- wide 'shunt vessel' that bypasses capillary beds
- richly innervated with sympathetic nerve fibres
242
what is the function of arteriovenous anastomosis in the nasal mucosa?
- help to warm inspired air
243
what is the function of arteriovenous anastomosis in the skin?
- temperature regulation
244
what are the characteristics of veins and venules?
- diameter 0.05-0.2 cm (venules), >0.2cm (veins)
- venules and veins only differ in size and number
- thin tunica media composed of smooth muscle and collagen
- easily distended
- often collapse
- in limbs, tunica intima have valves to prevent back flow
245
246
247
how resistant are veins and venules to flow?
not very
248
why are they also called capacitance vessels?
- they often contain up to 2/3s circulating blood at any one time
249
what are many veins innervated by?
- sympathetic (vasoconstrictor) nerve fibres
- makes smooth muscle contract and displace blood from this 'reservoir' of blood in veins during physiological stress
250
what is the general appearance of arteries vs veins?
- arteries = rounded
- veins = more irregular, often collapsed
251
what is the pressure of arteries vs veins?
- arteries = high
- veins = low
252
what is the relative oxygen concentration of arteries vs veins?
- arteries = higher in systemic, lower in pulmonary
- veins = lower in systemic, higher in pulmonary
253
which has valves present?
veins
254
what is hypertension?
- high blood pressure
- causes increased probability of coronary thrombosis, stroke and renal failure
255
what are the two forms of hypertension?
- primary (essential, most common)
- secondary
256
what is the cause of primary hypertension?
- unknown
- evidence of hereditary factor
- linked somewhat to smoking, obesity and western diet
257
what is the cause of secondary hypertension?
- occurs in 5% of cases
- caused secondary to primary hypertension or by a specific abnormality in one of the organs/systems of body
258
what are the treatments?
- antihypertensive drugs
- lifestyle changes are first line treatment
259
what drugs are used to treat?
- beta blockers
- ACE inhibitors
- calcium antagonists
- diuretics
260
what is the first line of management in hypertension?
- stopping smoking
- lose weight
- exercise regularly
- avoid stress
- reduce salt in diet
261
what is the aorta?
- largest artery in the body
- comes from left ventricle
- carries oxygenated blood
262
what 4 parts can the aorta be divided into?
- ascending
- arch
- descending / thoracic
- abdominal
263
what is the ascending aorta?
- left and right coronary arteries branch from here
- supply the heart
264
what is the aortic arch?
- arches overdo left side
- gives off 3 branches which supply head, neck and upper limbs
265
what is the first branch that's given off?
- brachiocephalic trunk
266
what does the brachiocephalic trunk divide into?
- right subclavian artery
- right common carotid artery
267
what are the other branches given off aortic arch?
- left common carotid artery
- left subclavian artery
268
what are common carotid arteries?
- at level of C3
- divide into internal and external carotid arteries
269
what does the internal carotid artery supply?
- brain
270
what does the external carotid artery supply?
- neck, face and scalp on its respective side
271
what are the subclavian arteries?
- below the clavicle
272
what is the subclavian artery a major supply to?
- arm
- thoracic wall
- shoulder (on respective side)
- neck (on respective side)
273
what does the subclavian artery become in the upper limb?
- axillary
- brachial artery
274
what do the brachial artery and axillary provide?
- arterial branches throughout the upper limb
275
what are the two major arteries in the forearm?
- ulnar
- radial arteries
276
what is the descending/thoracic aorta?
- sits left of vertebral column in thorax
- gives off branches that supply structures of thorax
277
what does the descending/thoracic aorta supply?
- oesophagus
- lungs
- thoracic wall muscles
- pericardium
- superior surface of diaphragm
278
what is the abdominal aorta?
- passes through diaphragm at level of T12
279
what does the abdominal aorta supply?
- abdomen
- pelvis
- lower limb
includes coeliac trunk, superior mesenteric artery, renal arteries, inferior mesenteric artery
280
what does the abdominal aorta split into?
- two common iliac arteries
- they travel towards pelvis and lower limb
281
what is the coeliac trunk?
- first unpaired branch of abdominal aorta
282
what does the coeliac trunk supply?
- structures of abdomen
- stomach
- liver
- gallbladder
- pancreas
- spleen
283
what is the location of the coeliac trunk?
- comes off abdominal aorta at vertebral level of T12
284
what is the superior mesenteric artery?
- second unpaired branch of abdominal aorta
285
what does the superior mesenteric artery supply?
- structures of abdomen
- most of small intestine
- proximal portion of large intestine
286
what is the location of the superior mesenteric artery?
- comes off at vertebral level of L1
287
what are the renal arteries?
- paired branches of the abdominal aorta
288
what do the renal arteries supply?
- kidneys
289
what is the location of the renal arteries?
- come off at vertebral level of L1/L2
290
what is the inferior mesenteric artery?
- third unpaired branch of abdominal aorta
291
what does the inferior mesenteric artery supply?
- hindgut structures of the abdomen (distal portion of large intestine
292
what is the location of the inferior mesenteric artery?
- comes off at vertebral level of L3
293
where do common iliac arteries form from?
- bifurcation of abdominal art at vertebral level of L4
294
what does the common iliac artery split into?
- internal iliac
- external iliac artery
295
what does the internal iliac artery supply?
- structures of pelvic cavity and perineum
296
what does the external iliac artery supply?
- lower limb on respective side
297
what does the external iliac artery continue as?
- femoral artery
298
where do capillaries drain into?
- venules
- venules then drain to veins
299
what are the largest veins that drain into heart?
- superior and inferior vena cava
300
in which direction is venous drainage?
- blood travelling towards the heart
301
what do veins have instead of branches?
- tributaries
302
what are the superior vena cava tributaries?
- internal jugular vein
- subclavian vein
- brachiocephalic vein
303
which tributary of superior vena cava drains most the blood out of head and neck?
- internal jugular vein
304
what does the subclavian vein drain?
- upper limb
305
what do the internal jugular and subclavian veins join to form?
- brachiocephalic vein
306
what does the azygous system drain?
- posterior thoracic wall
- drains into superior vena cava
307
what are the tributaries of the inferior vena cava?
- common iliac veins
- renal veins
- lumbar veins
- hepatic veins
308
what do the common iliac veins drain?
- structures of lower limb and pelvis
309
what is the portal venous system?
- collection of veins that drain into the liver before draining the IVC
310
where do the portal venous system veins originate from?
- digestive organs within the abdomen
311
what happens to the blood filtered by the lungs?
- its returned to the heart via hepatic veins and IVC
