Cardiovascular System Flashcards
1
Q
What are the boundaries of the thorax cranially, dorsally, laterally, ventrally snd caudally?
A
Cranial- thoraxic inlet
Dorsally- thoracic vertebrae
Ventrally- sternum
Caudally- diaphragm
2
Q
How many thoracic vertebrae are there?
A
13
3
Q
What do ribs articulate with?
A
thoracic vertebrae
4
Q
What is the dorsal 2/3 and ventral 1/3 of ribs made of and what is the junction called?
A
dorsal 2/3- bone
ventral 1/3- cartilage
costochondral junction
5
Q
How many ribs form the costal arch?
A
First 9 attach to the sternum, the next 3 form the costal arch the last is a floating rib
6
Q
How many bones make up the sternum?
A
8 sternebrae
7
Q
What is the name of the first and last sternebrae?
A
first is the manubrium the last is the xiphoid process
8
Q
What are the lobes of the left lung?
A
Cranial and caudal
9
Q
What are the lobes of the right lung?
A
Cranial, middle, caudal and accessory
10
Q
What lobe does a horse lack that most other domestic species have?
A
Middle lobe
11
Q
What lines the the thorax?
A
The pleura
12
Q
What are the two parts of the pleura?
A
visceral and parietal
13
Q
What does the visceral pleura cover?
A
The lungs
14
Q
What makes up the parietal pleura?
A
Medastinal, costal and diaphragmatic pleura
15
Q
What is there between the visceral and parietal pleura?
A
Potential space filled with serous fluid eliminating friction
16
Q
What part of the heart sits dorsally and cranially?
A
The base
17
Q
What part of the heart is ventral and caudal?
A
The apex
18
Q
In what direction does the heart lie?
A
Caudoventrally with slight left deviation to apex
19
Q
What covers the outside of the heart?
A
The pericardium (visceral and parietal)
20
Q
What are the layers to the body of the heart?
A
Inner layer of endocardium, muscular myocardium, outer epicardium
21
Q
What is the name of the valve between the left atrium and ventricle?
A
atrioventricular (bicuspid/mitral) valve
22
Q
What is the name of the valve between the right ventricle and atrium?
A
atrioventricular (tricuspid) valve
23
Q
What septettes the two atrium?
A
The interatrial septum
24
Q
What separates the two ventricles?
A
inter ventricular septum
25
What separates the right ventricle and pulmonary artery?
Pulmonic valve
26
What separates the left ventricle and aorta?
Aortic valve
27
What are the additional out pouches on the atriums called?
Appendage or auricle
28
What part of the heart receives oxygenated blood and where from?
Left atrium from pulmonary vein
29
What receives deoxygenated blood in the heart and by which vein?
right atrium via the venue cavae
30
What artery does blood leave the left ventricle by?
Aorta
31
What artery does blood leave the right ventricle by?
Pulmonary artery
32
What is contraction and relaxation phase of the cardiac cycle called?
contraction- systole
| Relax- diastole
33
Why is ventricle filling largely passive?
Atrial systole occurs at the end of ventricular systole
34
What is the stage between contraction/relaxation and change in volume?
isovolumetric contraction/relaxation
35
When does isovolumetric contraction occur?
before aortic and pulmonary valves open but after the AV valves close
36
When does isovolumetric relaxation occur?
Before the AV valves open but after the aortic and pulmonary valves close
37
What two sounds are audible in a normal animal?
Sound 1 and 2
38
In which animals can S3 and S4 be heard?
Horse and cow due to larger hearts
39
What causes S1?
The AV valves close and blood which has entered the ventricle rebound
40
What causes S2?
The pulmonary and aortic valves close and blood echos in the great vessels marking end of systole
41
Where can S3 be heard?
In horses or cats and dogs with heart failure
42
What causes S3?
Blood turbulence in left ventricle as it flows in from atria under pressure
43
When can S4 be heard?
In the horse or in small animals with a impaired relaxation of the ventricular wall
44
What causes S4?
Caused by an increased force of contraction of the atria to overcome the slow relaxation
45
What is an abnormal sound of the heart called?
Murmurs
46
What causes murmurs?
Anything that interferes with normal blood flow (thickened valve, narrow valve, incomplete valve, defect in septum)
47
On the left side of a dog where can a stethoscope be positioned to hear the pulmonary, aortic and mitral valves?
PAM- rib spaces 3,4 and 5
48
What can be heard on the right side of the dog?
tricuspid in rib spaces 4 and 5
49
What electrically insulates the atria and ventricles?
Annulus fibrosis
50
Describe the electrical activity which causes the cycle of the heart
Initial impulse generated by SAN, this travels cell by cell across atria causing contraction to AV node, which conducts impulse slowly to allow full atria contraction, it then enters the bundle of his, passes through annulus fibrosis and divides left bundle and right bundle branches, which branch to supply purkinje fibres, left divides into anterior and posterior fascicles, one part of right branch crosses to septomarginal band
51
What are valves made up of?
Cusps
52
How are the AV valves attached to the ventricular walls?
Cusps are joined by chordae tendinae to papillary muscles
53
What do the chordae tendinae prevent?
The cusps from inverting into the atrium
54
What proportion of fluid in the body makes up ECF, ICF?
ICF- 2/3, ECF- 1/3
55
In what vessel is blood carried away from the heart and towards?
Arteries away, veins towards
56
In what vessel does exchange occur?
Capillaries
57
What kind of arteries are found near the heart and why?
Elastic to withstand high pressures
58
What does an arteriole divide to become?
Pre-capillary arteriole intermittent smooth muscle and no elastic
59
What does the smooth muscle in precapillaries control?
regulates blood flow to capillary beds for precapillary sphincter zone
60
What is collateral circulation?
Where arteries give off side branched as a safety net incase of blockage
61
What are arteries called with no collateral circulation?
End arteries
62
What is a sinusoid?
A sinusoid is a modification of a capillary with gaps between lining of cells allowing free communication between blood and surrounding tissues
63
What is diapedesis and where does it occur?
The movement of cells out of a vessel lumen and occurs in post capillary venules
64
What are direct capillaries between arteries and venules referred to as?
Throughfare channels, metarterioles or arteriovenous capillaries
65
What vessels can shut the capillary bed for the most direct root?
Arteriovenous anastomosis
66
What layers are arteries and veins made of?
Tunica intima- endothelial lining
Tunica media- smooth/elastic tissue
Tunica adventitia- outer CT
67
Which layers do capillaries not have?
Tunica media or adventia
68
What do clefts of overlapped endothelial cells form in capillaries?
Gap junction for the movement of water soluble molecules
69
What are fenestrations?
an area where the endothelial cells is reduced to a thin membrane to allow increased transport of substances
70
What are the major velds of the heart?
Aorta, pulmonary trunk, cranial/caudal venae cavae, pulmonary veins and coronary arteries and veins
71
Describe the root of the pulmonary trunk
From the right ventricle, directs caudally and penetrates pericardium and divides left and right pulmonary arteries to corresponding lung
72
Describe the formation of coronary arteries
Left ventricle to aortic bulb, between atria it forms sinuses, cranial sinus to right coronary caudosinistral sinus to left coronary.
73
What does the aorta give rise to after the aortic bulb?
Brachiocephalic trunk and paired subclavian arteries
74
What does the brachiocephalic trunk give rise to?
Common carotid arteries
75
What 4 vessels do the subclavian arteries give off?
Vertebral, costocervical, internal thoracic and superficial cervical
76
What does the 4 vessels branched off the subclavian arteries supply?
Forelimb, neck, cervicothoracic junction and a portion of the brain
77
After the branches off the subclavian what remains and what does it supply?
Axillary and supplies forelimb and chest wall
78
What does the internal thoracic artery branch off?
The subclavian
79
What does the internal thoracic artery supply?
Pleura, pericardium, thymus, pectoral muscles, cranial mammary glands
80
What does the internal thoracic artery continue to become?
Cranial epigastric artery
81
Describe the direction of the thoracic aorta
Caudally along dorsal thoracic cavity, until the aortic hiatus of the diaphragm
82
What does the thoracic aorta supply?
The vertebrae, ribcage, lungs oesophagus
83
What branches of thoracic aorta supply ribcage?
Dorsal intercostal arteries and caudal ribcage by dorsal costoabdominal artery
84
What branch of the aorta supplies the lungs and oesophagus?
bronchoesophageal arteries
85
What branch of the abdominal aorta supplies the diaphragm and cranial abdomen?
Phrenicoabdominal arteries
86
What branch of the abdominal aorta supplies the lumbar tissues?
Lumbar arteries
87
What branch of the abdominal aorta gives off gastric, hepatic and splenic arteries?
Coeliac artery
88
What branch of the aorta supplies the small intestine?
Cranial mesenteric artery
89
What branch of the aorta branches off to supply the kidneys?
Renal arteries
90
What branch of the aorta supplies the reproductive organs?
Testicular or ovarian arteries
91
What branch of the aorta supplies the colon and rectum?
Caudal mesenteric artery
92
What branches of the aorta supplies the hind limb and pelvic viscera and gluteal muscles
hindlimb- external iliac arteries
| Pelvis- internal iliac artery
93
What does the aorta become to supply the tail?
median caudal artery
94
How is blood returned to the right atrium?
The caudal vena cava and coronary sinus
95
Where does the coronary sinus receive blood from?
The great cardiac vein and left azygous in ruminants and pigs
96
Where does the cranial vena cava receive venous return from?
The body cranial to the heart via azygous vein and internal thoracic
97
How is the head drained of blood?
Internal and external jugular vein
98
What vein drains the chest and forelimb?
Cephalic
99
What veins combine to form the cranial vena cava?
Axillary and subclavian
100
What drains the hindlimb?
External iliac veins
101
What drains the rectal and anal region?
Internal iliac vein
102
What veins fuse to form the caudal vena cave?
L and R common iliac, deep circumflex, testicular and renal
103
How does the caudal vena cava pass through the diaphragm?
Through the canal foramen
104
Where does the left coronary artery arise from?
Caudosinistral coronary sinus
105
What does the left coronary artery divide into?
Left inter ventricular artery and the circumflex artery
106
Where does the right coronary artery arise from?
Cranial sinus
107
When should an X-ray for examinations of lungs optimally be taken?
Peak inspiration
108
What side of the animal is touching the plate in left lateral recumbency?
Left
109
Why might elevation of the trachea occur?
Enlargement of the cardiac silhouette
110
Why might the heart be lifted off the sternum?
Air in the pleural cavity
111
What is the ventricular systolic pressure both left and right?
left- 120 mmHG,
| right- 25 mmHg
112
What is bulk flow?
Movement of fluid by means of pressure difference
113
What is perfusion pressure?
The difference in pressure between two points
114
What is transmural hydrostatic pressure?
Difference in pressure across a blood vessel
115
What is bulk flow in and out of a capillary called?
flow in- absorption,
| flow out- filtration
116
What effects the rate of diffusion?
The spleed of the substrate, the conc gradient, SA, distance
117
What do plasma proteins cause?
Plasma oncotic pressure
118
What does a high plasma oncotic pressure cause?
Water to move in to the vessel
119
How does water move in relation to oncotic pressure?
Low oncotic to high oncotic
120
What is the starling equation?
Net pressure= hydrostatic pressure - oncotic pressure
121
What does the starling equation show?
The net movement of water between capillaries and ISF
122
What does dilation of arterioles cause for filtration and absorption?
Increases hydrostatic pressure in the capillary causing filtration along the whole capillary
123
What is excessive ISF removed by?
Lymphatic system
124
What is a build up of ISF fluid called?
Oedema
125
What is a portal system?
Where capillary beds exist in series with one another
126
What are examples of portal systems?
Splenic, gastric and mesenteric capillary beds empty into the portal vein which goes to the liver. The kidney also has a portal system and the hypothalamus and pituitary gland
127
What is cardiac output?
the volume of blood pumped by one ventricle in a minute
128
What is the name for the blood which remains after systole?
End systolic ventricular volume
129
What is EDVV
End diastolic ventricular volume
130
What is the difference between EDVV and ESVV called?
Stroke volume
131
What is the ejection fraction?
The fraction of the EDVV that contributes to stroke volume (SF/EDVV)
132
What effects EDVV and ESVV
heart rate, preload, after load and contractility
133
What is cardiac output?
Strike volume x HR
134
How can EDVV/ESVV alter stroke volume?
Increase EDVV or decrease ESVV
135
What affects EDVV?
Filling time, compliance of ventricular wall and filling pressure (preload)
136
What is preload?
The filling pressure of the ventricle
137
How can preload be increased?
By increasing the pressure in the atria and veins
138
Why does preload increase during exercise?
Skeletal/respiratory muscle pumps as it contracts, and relaxes it pumps the contents towards the heart, the diaphragm compresses cranial abdominal veins
139
Why is too high of a preload lower SV?
too much stretching will cause damage to the myocardium and reduces contractility
140
Why does some stretching of the myocardium increase contractility
Increased calcium release from the SR
141
What is heterometric auto regulation?
Where the balance of stoke volume occurs as increased SV will cause and increase preload on the other side and increased SV
142
What is compliance of ventricle walls?
How readily ventricular walls stretch during diastolic filling
143
What is the equation of compliance?
Change in volume/
| change in pressure
144
What is lusitropy?
Ability of a ventricle to relax adequately
145
During a high HR how can SV be maintained?
By reducing the ESVV by increasing contractility
146
What is after load?
The ability of the heart to deliver its blood to the arterial system
147
What will a higher after load increase?
ESVV
148
What may sustained after load cause in the heart?
Myocardial hypertrophy
149
What is vascular resistance a measure of?
Compliance of the arterial system
150
How is resistance changed in blood vessels?
altering diameter
151
What is total peripheral resistance?
Net resistance of the whole circulation
152
What ate the two factors which influence aortic pressure?
total peripheral resistance and cardiac output
153
Why does arterial pressure remain about the same during exercise and rest?
TPR reduces due to dilation during exercise and CO increased
154
How does hypertension cause hypertrophy?
Increased pressure and therefore after load
155
What is the equation of a pulse?
systolic pressure - diastolic pressure
156
How can the mean arterial pressure be calculated except the aorta?
Diastolic pressure + 1/3 pulse
157
What words describe high pulse pressure and low pulse pressure?
High- bounding
| Low- thready
158
How is pulse pressure increased?
Increasing SV, reducing compliance, increasing TPR, reducing HR
159
How does the umbilical veins take oxygenated blood through the liver?
Via the hepatic sinusoids and ductus venosus
160
After passing through the ductus venosus where does the blood empty in a foetus?
Empties into the caudal vena cava and returns to right atrium
161
How is blood diverted from the right atrium to the left ventricle?
Foramen ovale
162
What assists the diversion of blood through the foramen ovale?
The eustachian valve
163
How is blood from the right ventricle redirected into the aorta?
By the ductus arteriosus
164
What happens to the umbilical arteries immediately prior to birth?
Contraction to stop blood flow
165
Why can the umbilical cord not be cut straight away?
Umbilical veins deliver 30% of blood volume which needs to take place
166
What happens to blood flow when the neonate takes its first breath?
It first pulls all the pulmonary capillaries open resulting is a huge drop in resistance to flow on the right side of the heart increasing blood flow to the lungs
167
What does increased flow to the the lungs cause?
Increased Venus return or preload to the left atrium increasing left atrial pressure
168
How is the foramen ovale closed after birth?
The right atrium no longer receives placental blood and the pressure difference pushes the septum premium against the septum secundum
169
After the closing of the foramen ovale what is the depression called?
Fossa ovalis
170
How is the ductus arteriosis closed?
Muscle in the ductus contracts closing the lumen, it is permanently closed by connective tissue
171
What is the remanent of the ductus arteriosis called?
ligamentum arteriosum
172
How long does it usually take to close the ductus arteriosis?
2-3 weeks
173
What us aortic stenosis?
narrowing of the aortic valve
174
What can be heard from an aortic stenosis?
A systolic heart murmur- usually high pitched
175
What is pulmonic stenosis?
Narrowing of the pulmonic valve
176
What causes a pulmonic stenosis?
Narrowing of the pulmonary artery or the valve
177
What does a pulmonic/aortic stenosis cause?
Increases after load on the ventricles causing hypertrophy of the muscle
178
What is patent ductus arteriosis?
The ductus arterioles remains open
179
What does patent ductus areteriosis cause?
Causes overload to the left side of the heart which could cause congestive heart failure
180
What is heard from patent ductus arteriosis?
Audible through systole and diastole in rib spaces 3 and 4
181
What can happen with patent ductus arteriosis if the lung vessels vasoconstrict?
Increases afterload on right ventricle, may >= aorta pressure causing deoxygenated blood to enter systemic circulation causing differential cyanosis (blue MMs)
182
What are ventricular septal defects?
Gaps int the interventicular septum
183
What is heard from ventricular septal defects?
Small- high pitched
| Large- lower softer at rib space 5 on the right side
184
What is a tetralogy of fallot?
4 defects- ventricular septal defect, dextraposed aorta, pulmonic stenosis, right ventricular hypertrophy
185
What are vascular ring anomalies?
A group of defects in development of the aortic arch which entrap the oesophagus and trachea
186
What is the most common vascular ring abnomaly?
most commonly persistent right 4th aortic arch combined with left ductus arteriosis
187
What does vascular ring abnormalities cause?
Causes an animal to struggle eating solid food and megaoesophagus
188
What is a congenital portosystemic shunt?
Anastomosis between the portal vein and the caudal vena cava
189
What does a congenital potosystemic shunt cause?
Blood cannot be decontaminated by the liver and toxins remain in the blood stream
190
What are clinical signs of congenital potosystemic shunt?
Stunted growth, copper irises in cats
191
How is an action potential propagated in the heart?
Cell to cell through intercalated discs
192
What is automaticity?
The ability to spontaneously depolarise and generate action potentials
193
What cells posses automaticity?
Pacemaker cells
194
What are cells called that develop automaticity after damage?
ectopic pacemakers
195
What does the autonomic nervous system affect in the heart?
Sympathetic increased HR and force, parasympathetic does the opposite
196
Why does the AV node slow down conduction of the AP?
To ensure full atrial contraction and emptying
197
What causes the plateau phase of the action potential in the heart ?
The Ca2+ channels
198
How do ions create the change in cardia myocytes membrane potential to change?
Fast Na+ channels open and almost immediately close and cell begins to repolarise, soon slow Ca2+ channels open via cyclin adenosine monophosphate causing the plateau phase, the Ca2+ causes calcium induced calcium release from the SR causing contraction, Ca2+ channels close and pumped into ECF
199
Why are Na+ channels in a cardiac muscle cell so long?
To prevent a new action potential being initiated before a previous one is completed
200
How does a atrial action potential differ to a ventricular?
Shorter due to Ca2+ channels being open for less time
201
What are Na+ channels called in a pacemaker cell?
Pacemaker or funny Na+ channels
202
When do pacemaker Na+ channels open and close?
Close during AP and ion once AP is finished
203
When do slow Ca2+ channels open in a pacemaker cell?
Just before the cell reached potential
204
What are the two axis of an ECG?
Voltage against time
205
What does an ECG measure?
The electrical potential difference between two electrodes
206
What does an ECG show if an action potential is traveling towards an electrode?
Upward deflection as there are more positive charges near the +ve electrode
207
What does an ECG show id an action potential is traveling away from an electrode?
Downward deflection as there are more negative charges near the +ve electrode
