Flashcards
Cardiovascular Y1
Cards in this deck (60)
- 1What is the root of the lugs called?The hilus
- 2Name the lobes of the lungs?Left has 2- cranial and caudal
Right has four: cranial, caudal, accessory and middle(horse lacks middle) - 3What pleura invests the lungs?Visceral
- 4What constitute the parietal pleura?mediastinal pleura
diaphragmatic pleura
costal pleura - 5The heart is encapsulated and invested by a serous membrane called?pericardium
- 6Layers of the heart?inner layer of endocardium, the muscular myocardium and the outer serosal epicardium which is confluent with the visceral pericardium
- 7Name the atrioventricular valves and how many cusps they have?The AV valves consist of fibrous ‘cusps’; the mitral valve has two cusps and the tricuspid in most species has three although in the dog the number of main cusps varies, with most having 2 main cusps and additional little commissural cusps at the edges.
- 8Atrium separated by?interatrial septum
- 9Ventricle separated by?inter ventricular septum which is really part of the left ventricle.
- 10What are the aortic and pulmonic valves known as?semilunar valves
- 11What brings blood the heart muscle?Coronary circulation.
- 12The contraction phase of the cardiac cycle is known as?Systole (squeezing)
- 13The relaxation phase of the cardiac cycle is known as?Diastole
- 14When are the trioventricular, aortic and pulmonic valve open/closed?Because of the direction of blood flow, it is easy to see that the atrioventricular valves are closed during ventricular systole, and open during ventricular diastole. The aortic and pulmonary valves are closed during ventricular diastole and open during ventricular systole.
- 15What is it called when the volume of the ventricle do not change doing contraction and relaxation?isovolumetric relaxation and isovolumetric contraction
- 16What are the phases of the cardiac cycle?isovolumetric relaxation
filling
isovolumetric contraction
emptying - 17When do isovolumetric relaxation and isovolumetric contraction start?Isovolumetric relaxation starts before the AV valves open but after the aortic and pulmonary valves close. Isovolumetric contraction starts before the aortic and pulmonary valves open but after the AV valves close.
- 18—1-stroke volume
2-ventricular ejection
3-Aortic valve opens
4-isovolumetric contration
5-mitral valve closes
6-EDV= end diastolic ventricular volume
7-ventricular diastole-filling
8-mitral valve opens
9-isovolumetric relaxation
10-ESV = end systolic ventricular volume
11- Aortic valve closes - 19What is this called?pressure-volume loop
1-stroke volume
2-ventricular ejection
3-Aortic valve opens
4-isovolumetric contration
5-mitral valve closes
6-EDV= end diastolic ventricular volume
7-ventricular diastole-filling
8-mitral valve opens
9-isovolumetric relaxation
10-ESV = end systolic ventricular volume
11- Aortic valve closes - 20S1?S1-The AV valves close and blood which has passed into the ventricle rebounds off the closed valve and walls. This is at the end of diastole and the beginning of isovolumetric contraction. A contribution is also made by the opening of the aortic valve and acceleration of the blood as it is squeezed into the aorta.
- 21S2?The pulmonary and aortic valves close and blood reverberates in the great vessels as it decelerates once the impetus of the ventricle is removed. This marks the end of systole.
- 22S3?Rarely audible except in the horse. Can be heard in dogs and cats with heart failure. Caused by blood turbulence in the left ventricle as blood flows in from the atria under pressure. It reflects reduced compliance of the (left) ventricle in early diastole.
- 23S4?Audible in the horse. In small animals it is associated with impaired relaxation of the ventricular wall (i.e. a stiff wall). Caused by increased force of contraction of the atria during atrial systole, as it endeavours to overcome the slow relaxation of the ventricular wall.
- 24What is a valve that is too narrow called?stenotic
- 25What electrically isolates the atriums and the ventricle while supporting the valves?Annulus fibrosus
- 26From the AV node the impulse enters?atrioventricular bundle /Bundle of His
- 27Each limb (of the Bundle of His) continues distally within the septum then branches out to supply the ventricular muscle via the?Purkinje Fibres
- 28The left bundle branch(of bundle of His) further subdivides intoanterior and posterior fascicles
- 29One part of the right bundle branch (of Bundle of His) crosses to the free wall of the right ventricle in a band of tissue called the?septomarginal band
- 30The valve cusps are joined by strands of fibrous tissue called? to muscular projections of the ventricular walls called?chordae tendinae
papillary muscles - 31What do the chord tendinae do?The chordae prevent the cusps from everting into the atrium during ventricular systole.
- 32What is it called when blood flows in the wrong direction?Regurgitation
- 33What percentage of body is fluid and what percentage of that is intracellular and extracellular?Mammalian bodies contain a large proportion of fluid – nearly 70% of the bodyweight – consisting of organic and inorganic solutes in water. Broadly speaking, two-thirds of this is fluid within cells (intracellular fluid), and one-third is fluid outwith cells (extracellular fluid).
- 34What makes up the extracellular fluid?The extracellular fluid is comprised of the blood plasma and the fluid between cells – the interstitial fluid which moves steadily through the extracellular space. The plasma and the interstitial fluid (ISF) are held in equilibrium, the maintenance of which is a function of the cardiovascular system.
- 35How do very active tissues get there exchanges they need? And give an example of an active tissue and a not so active tissue.Very active tissues that require fast, efficient exchanges need at least one capillary in contact with every cell (e.g. myocardium), whereas less active tissues can survive at a greater distance from the blood supply (e.g. hyaline cartilage).
- 36Where are large elastic arteries found?Near the heart e.g. the aorta
- 37What do arterioles divide into?Precapillary (or terminal) arterioles
- 38What is the system that accommodates increased blood flow when the main route is compromised?Most arteries give off side branches as a safety net in case of blockage of the main trunk. These are referred to as collateral circulation
- 39What is it called when there is a blockage to an end artery?ischemia
which, if persistent, leads to infarction and necrosis of the tissue - 40Do capillaries contain smooth muscle or elastic tissue?NO
- 41What is a sinusoid, and where can you find them?A modification of the capillary is the sinusoid, which also connect the arterial to the venous side of the circulation. These are very thin walled, relatively large diameter tubular channels occurring in several tissues, including the bone marrow and liver. There are gaps between the lining cells of sinusoids , allowing free communication between the blood plasma in the sinusoid and the surrounding tissues (e.g the Space of Disse in the liver), and movement of cells (e.g. from the myeloid tissue in the bone marrow into the blood). Blood moves through sinusoids slowly.
- 42What is the process that allows white blood cells to enter other tissues to fight infection?Diapedesis
After the capillary bed, the blood enters the post-capillary venules which still allow diffusion to occur and which allow the movement of cells out of the vessel lumen – a process called diapedesis. Diapedesis is the means by which white blood cells move out of the circulation and into tissues to fight infections. - 43What vessels enable a capillary bed to be shut off entirely (or opened up) depending on the needs of the bodyarteriovenous anastomosis
Run between an arteriole and a venule. - 44How is blood returned back to the heart?Veins do not actively contract; blood is returned to the heart passively, utilising pressure from within and outwith the vessel, and valves in many of the veins under gravitational pressure to prevent the backflow of blood.
- 45Arteries and veins have walls made up of three basic layers. These are:i. tunica intima which is the internal layer with an endothelial lining,
ii. middle tunica media which contains varying amounts of smooth muscle and elastic tissue
depending on the vessel
iii. external tunic adventitia, which is a layer of connective tissue. - 46What is the name of the blood supply to large arteries?the vasa vasorum which are small vessels that run in the adventitia.
- 47What are there branches that come off the aorta?1)aortic bulb. Here, the aorta is between the atria and forms sinuses (known as the sinuses of Valsalva); the cranial sinus gives rise to the right coronary artery and the caudosinistral sinus gives rise to the left coronary artery. These coronary arteries provide the blood supply to the heart muscle itself.
2)After the aortic bulb, the aorta gives rise to the brachiocephalic trunk and paired subclavian arteries. In larger species, these vessels are combined initially as the brachiocephalic trunk which courses cranially before dividing. In the dog and pig, the left subclavian artery remains distinct, arising from the aorta slightly caudally from the brachiocephalic trunk. The brachiocephalic trunk gives off the common carotid arteries which supply most structures of the head. - 48Where does the cranial vena cava receive blood from?The cranial vena cava receives all the venous return from the body cranial to the heart, as well as the drainage from the thoracolumbar area and ribcage via the azygous vein (in most species) and the internal thoracic vein. The azygous vein passes through the aortic hiatus of the diaphragm (see dissection).
The head is drained by the internal and external jugular vein, the external being the more prominent. The cephalic vein drains the cranial chest and forelimb. The axillary vein joins the subclavian vein draining the forelimb and some of the intercostal area. These veins combine to form the cranial vena cava.
The vertebral venous plexus drains (see CNS lectures) into the vertebral vein which enters the cranial vena cava just cranial to the azygous vein . - 49Where does the caudal vena cava receive blood from?The caudal vena cava receives the majority of venous return from caudal to the heart. The rectum and anal region drain towards the internal iliac veins, which joins the external iliac veins which drain the hindlimb to form the left and right common iliac veins. These fuse and are joined by the deep circumflex iliac veins and the testicular/ovarian veins and renal veins to form the caudal vena cava.
The portal vein drains most of the gastrointestinal tract, and then hepatic veins drain into the caudal vena cava. The caudal vena cava courses cranially through the diaphragm via the caval foramen then runs in the plica vena cava in the thorax to the right atrium. - 50What is the heart innervated by?Automatic nervous system
- 51Wher does the sympathetic nervous system arises from? (and the pre/postganglionic fibres)thoracolumbar spinal segments. Preganglionic axons are (mostly) short, and enter the sympathetic trunk which is a long chain of ganglia running lateral to the vertebrae on both sides. This chain extends beyond the thoracolumbar area – there are more sympathetic ganglia than there are spinal segments supplying them.
The postganglionic sympathetic supply to the thoracic viscera arises from sympathetic ganglions C5- T3. These ganglia combine to form two larger ganglia called the stellate ganglion and the middle cervical ganglion. The middle cervical ganglion consists of sympathetic ganglia C5 and C6 while the stellate ganglion consists of sympathetic ganglia C7-T3. Remember that the preganglionic fibres running to these ganglia arose from thoracolumbar spinal segments and are running cranially to these ganglia. - 52Where does the parasympathetic nervous system rise from?The parasympathetic nervous system arises from the brainstem and the sacral spinal segments. The preganglionic fibres are generally long and synapse with the postganglionic fibres at or near the target organ.
The parasympathetic supply to the thoracic viscera arises from the brainstem and runs to the thorax in cranial nerve X – the vagus nerve. - 53What is the basic role of the sympathetic and parasympathetic system?The sympathetic nervous system acts to increase cardiac output, and is capable of full activation in times of extreme need – the fight-or-flight response. The parasympathetic nervous system is generally in control when animals are resting, and tends to lower cardiac output – it is the rest-and- digest system.
- 54What happens when activation of the full sympathetic nervous system occurs?α-adrenergic activation causes constriction of the arterioles of the non-essential organs to divert blood to cardiac and working skeletal muscle, and venoconstriction of the abdominal organs to maximise preload to the heart and hence increase cardiac output. Cardiac output is also increased by β1 activation which leads to increased heart rate and conduction, reduced refractory period and stronger cardiac contractions. The blood supply to cardiac and skeletal muscle is optimised as β2 adrenergic and M3 cholinergic receptor activation causes vasodilation in these organs.
- 55What are the five systems at work in managing the cardiovascular system during exercise:metabolic auto regulation
psychogenic response
exercise reflex
baroreflex
skeletal muscle and respiratory pumps - 56What is metabolic auto-regulation?Increase in skeletal muscle activity means vasodilation in the working muscles as metabolic waste products (CO2, H+, K+) build up in the interstitial fluid. This would lead to a reduction in arterial pressure, having deleterious effects on other body systems were it not for other compensatory mechanisms.
- 57What is the psychogenic response?Before exercise even commences, a psychogenic response from the CNS increases sympathetic
activity to the heart and blood vessels, and decreases parasympathetic activity to the heart. This leads to increased cardiac output by direct effects on the heart: increasing contractility, heart
rate and speed of conduction. Remember that during sympathetic stimulation the increased heart
4
rate does not negatively impact diastolic filling, as systole is shortened disproportionately in order to preserve diastolic filling time.
CO is further increased by increased preload (which increases stroke volume) as venous return to the heart increases due to vasoconstriction in the non-essential organs. This vasoconstriction also increases TPR which in turn offsets the arterial dilation in skeletal muscle and, along with the raised CO, maintains BP.
In intense exercise, sympathetic stimulation causes contraction of the muscular capsule of the spleen to expel the blood contained in this organ into the circulation.
The psychogenic response is graded and modified depending on the intensity of the exercise - 58What is the exercise reflex?During exercise, the exercise reflex also modifies the degree of sympathetic and parasympathetic activity to the cardiovascular system. Specialised nerve endings in muscles and joints assess the intensity of exercise and feed back to the autonomic nervous system.
- 59What does the baroreflex do?If the psychogenic response and exercise reflex are insufficient to maintain arterial blood pressure (ABP) during exercise, the drop in BP is perceived by the baroreceptors in the aortic arch and carotid sinuses. In response to the drop in pressure the baroreflex further increases sympathetic and decreases parasympathetic activity.
Equally, if the psychogenic response and exercise reflex overshoot, raising ABP too high, the baroreflex can moderate the autonomic nervous system output to normalise the ABP. - 60What are the skeletal muscle and respiratory pumps?The two other systems which help to increase cardiac output during exercise are the skeletal muscle
pump and the respiratory pump.
Rhythmic contractions of skeletal muscles squeeze the venous contents therein towards the heart,
thereby increasing preload which in turn increases stroke volume and therefore cardiac output.
Increased depth of respiration distends the central veins, which draws blood from the abdominal veins into the central circulation, increasing preload. Also, caudal movement of the diaphragm during deep inspiration increases abdominal pressure, further emptying the abdominal veins and increasing preload.
Information
- Description
- Veterinary Medicine Flashcards on Cardiovascular Y1, created by Heather M on 15/08/2018.
- Created by
- Heather M
- Views
- 3
- Rating