Cardiovascular system Flashcards
(151 cards)
1
Q
the function of the cardiovascular system?
A
- the heart maintains adequate pressure to circulate blood and everything it carries to the entire body via the vasculature
2
Q
the function of the heart
A
provides the FORCE to circulate the blood to the entire body
3
Q
what are the major components of the cardiovascular system?
A
- heart
- blood vessels (arteries, arterioles, veins, capillaries, lymphatics)
- blood
- lymph
4
Q
the function of the arteries
A
- carry blood AWAY from the heart
- normally oxygenated (the exception is the pulmonary artery)
5
Q
which artery is not oxygenated?
A
pulmonary artery
6
Q
what is the function of the veins?
A
- carry blood towards the heart
- normally de oxygenated blood (exception is pulmonary vein)
7
Q
which vein carries oxygenated blood?
A
pulmonary vein
8
Q
describe the shape of the heart
A
- cone shaped
- hollow
- muscular
- 4 chambers
- tilted, the long axis of the heart forms a 45-70 degree angle with the sternum
- apex faces downward and the base is cranial
9
Q
where is the heart found?
A
- within the thorax
- in the mediastinum (slightly to the left)
- between the 3rd and the 6th pair of ribs in dogs and the 4th-7th in cats
10
Q
what is the mediastinum?
A
space between the lungs
11
Q
describe the base of the heart
A
- wide end
- cranio-dorsal end
- the site where blood vessels enter and exit
- non mobile
12
Q
describe the apex of the heart (4)
A
- pointed end
- free (mobile)
- caudo-ventral (towards the sternum)
- parietal pericardium attached by ligament to sternum
13
Q
what are the layers of the heart wall?
A
epicardium
myocardium
endocardium
14
Q
how many layers is the pericardium/ pericardial sac?
A
2
- Outer: outer layer
- inner: epicardium
15
Q
describe the pericardium
A
- completely closed, 2-layered membranous sac around the heart
16
Q
describe the outer layer of the pericardium (4)
A
- fibrous
- thin but tough fibrous connective tissue
- contains viscous fluid
- reflects onto the heart at the base
17
Q
describe the inner layer of the pericardial sac
A
- more delicate layer
- aka serous pericardium
- has 2 layers (parietal and visceral layer)
- the space between the 2 inner layers is called the pericardial cavity and is filled with pericardial fluid
18
Q
describe the parietal layer of the heart
A
- a layer of the epicardium (inner layer of the pericardium)
- adheres to the fibrous pericardium
19
Q
describe the visceral layer of the heart
A
- a layer of the epicardium (inner layer of the pericardium)
- adheres to the myocardium
20
Q
describe the pericardial cavity
A
- space between the 2 layers of the epicardium
- is filled with pericardial fluid
21
Q
what is the function of pericardial fluid?
A
- to reduce friction when the heart beats
22
Q
what are the 4 functions of the pericardial sac?
A
- protects the heart
- fixes the heart’s position in the chest (via the ligament to the sternum, attaches at the base of the heart)
- lubricates
- helps relax the heart during diastole by exerting a small negative pressure
23
Q
describe the myocardium
A
- the middle layer of the heart wall
- thickest layer
- cells are striated and branched
- cells form continuous sheets of muscle
- the muscle does not tire
- intercalated discs connect the muscle cells
- all the cells contract and relax as a unit due to the low electrical resistance (allows the impulse to spread quickly)
24
Q
describe the endocardium
A
- serous membrane
- the lining of the chambers of the heart
25
describe the atria
- near the base
- external cauliflower-like border called auricle(s)
- entrance for major veins
- hollow
- thin-walled
- inner surface covered by a network of muscular ridges called the musculi-pectinati
26
what is musculi-pectinati?
the network of muscle ridges in the atria
- function possibly for traction
27
describe the ventricles (8)
- largest chambers
- hollow
- thicker walled
- at the apex
- major muscular pump
- blood leaves through arteries from here
- The left side is thicker because it pushes into the body
- coronary arteries found over the surface
28
describe the inter-ventricular septum
- thick muscular wall separating the left and right ventricles
29
how many valves are in the heart?
4
30
how are the cardiac valves oriented?
toward the base
31
why are the cardiac valves all on a similar level/plane?
to control the flow of blood through the heart in one direction
32
what are the 2 groups of cardiac valves?
-atrio-ventricular valves
- semi-lunar valves
33
describe the AV valves
- located between an atrium and a ventricle
34
describe the right AV valve
tricuspid
35
describe the left AV valve
bicuspid
36
which is the only bicuspid valve?
the left AV valve
aka mitral valve
37
describe the aortic semilunar valve
- located between the left ventricle and the aorta
38
describe the pulmonary semilunar valve
- located between the right ventricle and the pulmonary artery
39
what is a cusp when referring to cardiac valves?
- thin flaps of connective tissue
- are arranged to meet other cusps to form a seal
40
describe chordae tendinea
- fibrous connective tissue cords
- aka heartstrings
- attach to the free edge of AV valve cusps and the ventricle wall
- resemble parachute cords
- prevent eversion of the valve into the atrium (prevents the valve from flipping)
41
describe the papillary muscle (3)
- prominent muscular projections
- on the inner aspect of the ventricle wall
- are attachment points for the chordae tendinae
42
describe the trabeculae carnae cordis
- are muscular ridges covering the inner surface of the ventricle wall
43
what are the major blood vessels entering the heart?
- superior and inferior vena cave
- pulmonary vein
44
What major blood vessels exit the heart?
- aorta
- pulmonary artery
45
which major blood vessels/supply are found within the heart?
the coronary artery and vein (coronary vessels)
46
what are the 4 major divisions of the mammalian circulatory system?
- systemic (to the cells)
- pulmonic (to the lungs)
- coronary (to the heart cells)
- portal (brings nutrients from the GIT to the liver for processing/filtration before joining systemic circulation)
47
describe pulmonary circulation (2)
- the right side of the heart
- from the vena cava to the pulmonary vein
48
describe systemic circulation
- left side of the heart
- from the left atrium to the rest of the body
49
name the branches coming off the aorta of cats and dogs
- brachiocephalic artery
- left subclavian artery
50
which artery is also known as the innominate artery?
the brachiocephalic artery
51
what does the brachiocephalic artery further branch into:
- right subclavian artery
- right common carotid
- left common carotid
52
describe coronary circulation
- provides nutrients and oxygen to the myocardium
- removes carbon dioxide from the myocardium
53
describe the muscles of the electrical conduction system of the heart
- specialized cardiac muscle cells
- can convey an impulse
54
what is called the pacemaker of the heart
SA node
55
where in the electrical conduction system of the heart is the electrical potential delayed for a fraction of a second?
at the AV node
56
what does an electrocardiogram tell us?
the measurement of the cardiac electrical activity through the body tissues
57
what is a Galvanometer?
- an instrument that records the electrical activity of the heart at the surface of the body
- leads are used to record the electrical activity
- represents electrical activity as a wave (PQRST wave)
58
where is lead 1 of a galvanometer placed?
- right front
- usually white
59
what does lead 1 of a galvanometer tell us?
- registers the electrical activity across the left forelimb to the right forelimb
60
where is lead 2 of a galvanometer placed?
left front
- usually black
61
what does lead 3 of a galvanometer tell us?
- registers activity of the right forelimb to the left hindlimb
62
where is lead 3 of a galvanometer placed?
left hindlimb
usually red
63
what does lead 2 of a galvanometer tell us?
- registers the electrical activity from the left hindlimb to the left forelimb
64
what does an ECG show us?
- represents the electrical activity of the heart
- problems with the electrical impulse (ie depolarisation and repolarisation) can be seen visually and diagnosed non-invasively
- used routinely to monitor and diagnose
- represents one complete heartbeat
65
what is the P wave?
- represents the electrical activity as it spreads from the SA node across the left and right atrial muscle
- is the activation of the atria
66
what is the QRS complex?
- measures ventricular activity from the AV node to the muscles of the ventricle
- causes depolarisation and contraction
- activation of the ventricles
67
what is the T wave?
- represents repolarisation of the ventricle
- heart recovers and goes back to normal
68
describe a heart block
- any interruption in the cardiac impulse pathway
- results in normal atrial beat and a slow ventricular rate
69
where does heart block commonly occur?
at the AV node
70
what are the 2 major periods of the cardiac cycle?
systole
diastole
71
describe systole
- period of active contraction resulting in partial emptying of the chamber
- can be left or right atrial or ventricular systole
72
when does the cardia cycle begin?
at the stage of atrial diastole
73
what causes the opening of the AV valve?
- blood enters the atria which increases the pressure
- when atrial pressure exceeds ventricle pressure, the AV valve opens
aka atrial diastole
74
what occurs during atrial diastole?
- blood enters the atria which increases the pressure
- when atrial pressure exceeds ventricle pressure, the AV valve opens
75
What happens during atrial systole?
(atria are contracting)
- SA node fires (this causes the atria to contract which pushes more blood into the ventricles)
- when the pressure in the ventricles exceeds atrial pressure, the AV valve suts
76
what does auscultation reveal (very basically)?
- 2 distinct heart sounds
- Lubb
- Dupp or Dubb
it goes: lubb, dubb, pause
77
describe the 'Lubb' heart sound
- lounder
- lower pitched
- longer duration
- represents the closure of the AV valves when the ventricles are contracting
- systole
78
describe the 'dubb' heart sound
- short
- sharp sound
- represents the vibrations of the pulmonary and aortic arteries and closure of the semi-lunar valves
- diastole
79
which heart valve/cusps are more likely to stop closing properly (develop a heart murmur)?
- bicuspid valve
80
what does the absence/muffled heart sounds indicate? (3)
- increased fluid around the lungs
- pleural effusion
- pericardial effusion
etc
81
which nervous system controls the heart rate?
autonomic NS (involuntary)
82
how does the parasympathetic NS affect the heart rate?
- via the vagus nerve:
1. decreases force and rate of contraction of the heart
2. decreases the conduction of impulses through the heart
3. decreases coronary blood flow
slowing down
83
how does the sympathetic NS affect the heart rate?
- increases force and rate of contraction
- increases the conduction rate of impulses through the heart
- increases coronary blood flow
- speeding up
84
what factors influence heart rate?
- body size
- age
- breed
- health
- metabolic rate
- fitness
- individual variation
- environmental (conditioning, diet, altitude)
- chemicals (hormones)
- temperature
- behavior
- respiratory rate
85
define a vessel:
any channel for carrying fluid (eg, arteries, capillaries, and veins)
86
describe an arteries
- thick-walled (stronger than veins)
- small lumen
- don't collapse
- greater pressure
- variable size
- 3-layered structure
- deep to the veins
87
what is the inner layer of an artery called?
- tunica intima
88
describe the tunica intima (3)
- inner layer of an artery
- epithelial (endothelial) lining
- has elastin and connective tissue
89
what is the middle layer of an artery called?
- tunica media
90
describe the tunica media
- the middle layer of the artery wall
- primarily smooth muscle and some elastin
91
what is the outer layer of the artery wall called?
- tunica externa or Tunica adventita
92
describe the tunica externa
- the outer layer of the artery wall
- primarily fibrous connective tissue
93
name the 3 layers of the artery wall
- tunica intima
- tunica media
- tunica externa
94
describe arterioles
- small arteries
- lead to capillaries
- regulate blood flow into capillaries
95
right-sided heart failure leads to what?
- fluid build-up around the lungs
96
left-sided heart failure leads to what?
blood in the abdomen (distended, has a fluid wave)
97
are there any internal structures in an artery?
no
98
is there an extra type of tissue in arteries?
yes, elastin
99
what tissues are found in the middle layer of the vein wall?
- primarily connective tissue
100
describe capillaries
- are only 1 epithelial cell thick (8 microns) upon a basement membrane
- is semi-permeable and allows the exchange of gas, nutrients, and wastes
- is a network of small vessels
101
describe a capillary bed?
- a network of capillaries
- hydrostatic pressure drops from the arterial to the venous side of the capillary bed
- osmotic pressure increases from the arterial to the venous side
102
describe a vein (6)
- thinner walled
- larger lumen
- 3 layered wall (similar to arteries but lacks smooth muscle and elastin)
- can collapse
- unidirectional valves to prevent backflow
- muscle movement of the body helps with pumping
103
why are the valves in veins useful?
- prevents backflow
- low venous pressure
104
define blood pressure
- the pressure (force) that the blood exerts against the arterial vessel wall
105
what is BP affected by in the blood vessels?
- elastin, dilation, and constriction of smooth muscle
106
what is used to measure BP?
- arterial canulation (carotid, dorsal pedal)
- sphygmometer
107
what is BP influenced by?
- heart rate
- force of contraction (ventricles)
- resistance in the blood vessel walls (can be due to elastin, smooth muscle, thickness)
108
how is a sphygmometer used?
- place an inflatable cuff above the elbow (over the humerus)
- inflate the cuff until the pressure stops blood flow
- auscultate with a stethoscope below the cuff
- release pressure from the cuff slowly until you can hear the pulse (this represents the 1st sound = diastolic pressure)
- then note when the sound abruptly changes (this is the 2nd sound = diastolic pressure)
- shortly after the sun will disappear
109
using a sphygmometer, what does the 1st sound represent?
systolic blood pressure
110
when using a sphygmometer what does the second sound represent?
diastolic BP
111
what blood pressure does 130 mm Hg represent?
systolic BP
112
what blood pressure does 82 mm Hg represent?
diastolic BP
113
what blood pressure does 78 mm Hg represent?
no sound
114
what is systolic BP
the max pressure in arteries during ventricular contraction
115
what is diastolic BP?
the lowest pressure in arteries during ventricle relaxation
116
describe a pulse
- a wave of systolic pressure
- can be felt superficially with slight pressure over an artery
- begins at the heart
- spreads through the arterial network
117
IBD
invasive blood pressue
118
NIBP
non invasive blood pressure
119
common pulse assessment areas in cows are:
- facial artery
- middle coccygeal artery
120
common pulse assessment areas in horses are:
- facial artery
- digital artery
121
common pulse assessment areas in sheep and goats are:
- femoral artery
122
common pulse assessment areas in cats and dogs are:
femoral artery
123
in the fetus which organs are non-functional?
- lungs
- kidneys
- digestive system
124
in fetal circulation where does gas/nutrient/waste exchange occur?
on the placenta
125
what different vessels do fetuses have? (4)
- ductus arteriosus
- foramen ovale
- ductus venosus
- umbilical arteries
126
describe the ductus arteriosus
- shunts blood from the pulmonary artery into the aorta
- bypasses the lungs
- classes off at or shortly after birth
- failure to close results in a murmur
127
describe the foramen ovale
- shunts blood from the right atrium to the left atrium
- normally classes at or shortly after birth (is the one most likely not to close)
- failure to close is called a 'hole in the heart'
128
describe the ductus venosus
- shunts blood from the umbilical vein to the caudal vena cava (small amount goes to the liver)
- normally closes at birth (becomes 'round ligament', failure to close results in a liver shunt which requires sx)
129
describe the umbilical arteries
- returns poorly oxygenated blood and wastes to the placenta and the mother
- closes at birth when the umbilicus is torn
130
in fetal blood flow the blood in the umbilical vein divides into what?
- hepatic portal vein ( to the liver)
- ductus venosus (most blood goes this way)
131
in fetal blood flow, what does the ductus venosus connect to?
post vena cava
132
what are the 4 functions of the lymphatic system?
- returns/ absorbs protein-containing fluid from tissue and returns it to circulation (prevents pooling/edema)
- transports fats from the digestive tract to the blood
- produces lymphocytes
- develops immunity
133
what are the 4 components of the lymphatic system?
- lymph
- lymph vessels
- lymph nodes
- lymphocytes and monocytes
134
describe lymph
- transparent-slightly yellow liquid
- is approximately 95% water (the rest is plasma protein and other normal substances)
- contains lymphocytes
135
what filters lymph?
the lymph nodes, as the lymph travels through the lymph vessels
136
describe lymph vessels
- one way
- thin-walled
- unidirectional valves (has more than veins)
- parallel to the venous system
begin as blind-end lymph capillaries
- empty into the blood circulation
137
describe the lymph nodes
- discrete, nodular, oval-shaped structures scattered along the course of the lymph channels
- filters lymph
- produces lymphocytes
- surrounded by a capsule (connective tissue)
- there are connective tissue partitions are sent into the center of the node
- is divided into the cortex and medulla
- afferent lymph vessels enter the node at multiple sites
- a single vessel leaves the node
- cortex contains many target-like structures (known as lymphatic nodules which contain lymphocytes)
- medulla contains cords of lymphocytes/plasma cells
138
what are the 6 lymph nodes?
- submandibular
- parotid
- prescapular
- axillary
- inguinal
- popliteal
139
what are the lymph organs?
- tonsils
- spleen
- thymus
140
describe the tonsils in respect to the lymphatic system
- a mass of lymphoid tissue embedded in a mucus membrane
- supplied with reticuloendothelial cells
141
describe the spleen in respect to the lymphatic system.
- is the largest mass of lymphoid tissue
- phagocytic function
- produces lymphocytes
- stores and releases blood as needed
142
describe the thymus in respect to the lymphatic system
- important in developing immune response in the young
- is eventually replaced by fat in the adult (depending on the species)
143
define edema
- increased fluid between the cells
144
what causes edema?
- greater retention of existing fluid
- too much fluid entering the compartment
145
what does edema cause?
- increased arteriolar pressure
- starvation (decreased plasma proteins)
- lymph obstruction
- increased blood capillary permeability
146
how to treat edema?
- diuretic
- proper nutrition
- reduced hydrostatic blood pressure (smooth muscle relaxants, decrease heart rate)
147
define shock
- an insufficient effective volume of circulating blood to perfuse the tissues with nutrients and remove wastes
148
what is the effect of shock?
- preserve circulation to the core organs
- peripheral circulation is significantly reduced (vasoconstriction)
149
what causes shock?
- blood vessel damage (hemorrhage)
- dilation of visceral blood vessels
- loss of fluid into tissues
- failure of blood to return to the heart
- failure of the heart to pump enough blood
150
what physiological changes do you see with shock?
- altered respiration
- peripheral areas of the body become cold
- loss of consciousness
- possibly death
151
treatments for shock
- restore fluid volume
- stop bleeding
- can give corticosteroids or immunosuppressants (depending on the initial cause)
