AT3: Cardiovascular System Flashcards
(140 cards)
1
Q
Functions of blood
A
- To transport nutrients and wastes around the body
- To regulate body temp. Through VD+ VC/ blood plasma
- To regulate pH
- To maintain fluid and electrolyte balance
- To protect the body against infection via WBCs
- To transport toxins out of the body
2
Q
Structure of blood
A
-cells, cell fragments, plasma
3
Q
Erthyrocyte
A
Red blood cell
4
Q
Leukocyte
A
White blood cell
5
Q
PLT
A
Platelet
6
Q
% of plasma in blood
A
55%
7
Q
% of RBCs in blood
A
45%
8
Q
What does the buffy coat contain
A
PLT and WBCs
9
Q
% of buffy coat in blood
A
Less than 1%
10
Q
Structure of RBCs
A
Biconcave shape
Have no nucleus
Contain haemoglobin
11
Q
Function of RBCs
A
To transport o2 around the body
12
Q
How does structure of RBCs help function
A
Biconcave-> inc. SA:V ratio-> inc. rate of oxygen diffusion in and out of cell
Inc. flexibility-> squeeze through small capillaries-> delivers o2 close to each cell
No nucleus-> more space for Hb-> inc. o2 carrying capacity
13
Q
WBCs structure
A
Largest of all blood cells
14
Q
WBCs function
A
- to protect the body against infection by digesting pathogens
- to provide immunity by producing antibodies in response to pathogenic antigens
15
Q
Platelets structure
A
-no nucleus
-small fragments of cells
16
Q
Function of platelets
A
To allow blood to clot through thrombosis and coagulation
To prevent entry of pathogens into body
- to prevent excess blood loss
17
Q
Haemostasis process
A
Injury-> vascular spasm/ vasconstriction-> platelet plug formation -> coagulation
18
Q
Injury: haemostasis
A
A blood vessel is severed. Blood is leaking out of breaks
19
Q
Vascular spasm/ vasconstriction :haemostasis
A
Smooth muscle in vessel wall vasoconstriction reducing blood loss from injury site
20
Q
Platelet plug formation: haemostasis
A
Platelets activated and stick to each other and the wound site-> forms a primary plug to stop the bleeding
21
Q
Coagulation: haemostasis
A
Fibrinogen (inactive) converted to fibrin (active)-> fibrin meshwork form and traps PLTs and strengthens the clot
22
Q
Structure of plasma
A
Liquid part of blood
Consists of water with dissolved chemicals in it
23
Q
Function of plasma
A
To transport substances around body
To help regulate body temp. Through sweat
24
Q
Substances in plasma
A
Nutrients e.g glucose
Wastes e.g CO2, urea
Plasma proteins e.g antibodies
Hormones e.g insulin
25
WNL for pH
7
26
WNL pH for blood
7.3 to 7.45
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Blood pH below 7.3
Acidic
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Blood pH above 7.45
Basic
29
What happens to pH if it becomes more acidic
Bicarbonate buffer system removes excess H+ ions
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What happens if pH rises/ becomes more basic
Bicarbonate buffer system releases H+ ions
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Hypovolemia
Abnormal condition of low blood plasma levels
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Possible health risks of Hypovolemia
-dehydration
- potentially fatal Hypovolemic shock
- inc. risk of infection b/c not transport WBC efficiently
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Regulating blood pH
Bicarbonate buffer system= primary mechanism for maintaining blood pH
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What happens in bicarbonate buffer system
Carbonic acid dissociates into H+ ions and bicarbonate ions
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What is an open circulation loop
Contains a different start and end point where substances enter/exit
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What is a closed circulation loop
Contains the same start and end point
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Is the CVS an open or closed circulation loop
Closed
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Systemic circulation
- transports oxygenated blood from the heart to body tissues/organs
- transports deoxygenated blood and waste from the body tissues to the heart
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Pulmonary circulation
-transports deoxygenated blood from the heart to the lungs via pulmonary artery
- transports oxygenated blood from the lungs to the heart via pulmonary vein
40
Arteries structure
Thick, muscular wall
Small lumen
41
Arteries function
To provide a pathway for blood away from heart
(Blood travels at a high pressure through arteries)
42
Arterioles structure
Branch off the arteries
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Arterioles function
To direct oxygenated blood from a major artery into the capillary beds
44
Capillaries structure
Single layer of epithelial cells
One cell thick
45
Capillaries function
To allow for gaseous exchange of nutrients and wastes from blood and tissues
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Venules structure
Capillaries converge into venules which converge into the vein
47
Venules function
To direct deoxygenated blood from a capillary to a vein
48
Veins structure
Thin, floppy walled
Large lumen
One way valves
49
Function of veins
To provide a pathway for blood to the heart from body tissues/organs
(Blood travels through veins at low pressure)
50
What do the coronary blood vessels do
Branch from the aorta and supply the heart with blood
51
What happens in an MI
There is reduced blood flow in a coronary artery
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Right atrium function
To receive deoxygenated blood from the vena cavae and empty it into the right atrium
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Left atrium function
To receive oxygenated blood from the lungs via the pulmonary vein and empty it into the LV
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Function of atria
To receive blood
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Function of ventricles
To pump blood out of the heart
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RV function
To pump deoxygenated blood from the right atrium to the lungs via the pulmonary artery
57
LV function
To pump oxygenated blood from the left atrium to the body via the aorta
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Pericardium description
A fibrous sac that encapsulates the heart
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Myocardium description
Compromised of cardiac muscle and transmits electrical stimuli
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Endocardium description
Lines the chambers and valves of the heart
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Septum description
A muscular wall between the left and right sides
62
Function of septum
To separate the left and right sides of the heart
63
Bicuspid valve
Found of left side
Has 2 flaps
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Tricuspid valve structure
Found on right side
3 sides
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Chordae tendinae structure
Thin string fibrous chords connecting leaflets of bicuspid and tricuspid valve to papillary muscle
66
Function of chordae tendinae
To help regulate opening and closing of the valves
67
Why does the LV have a thicker wall than RV
LV pumps blood to entire body t/f needs more muscle to generate higher pressure
RV only pumps blood to lungs
68
What is the cardiac cycle
A series of pressure changes that occur in the heart
69
Systole
When the heart contracts to pump blood out
70
Diastole
When the heart relaxes after contraction
71
Auscultation
A method used to listen to sounds of the body during physical examination using a stethoscope
72
What happens in atrial diastole
- all heart muscle in relaxation
- all heart valves are closed to prevent backflow
- blood returning to atria
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What happens in atrial systole
- atria in contraction
- AV valves open to allow blood to flow through
-SL valves close to allow fill
- blood to ventricles
74
What happens in ventricular systole
-Ventricles in contraction
- SL valves open to allow blood flow out of ventricles
- AV closed to prevent backflow
- blood passing to arteries (out of heart with highest pressure)
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What happens in ventricular diastole
-all heart muscle in relaxation
- all heart valves are closed
-blood returning to atria
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What is arrhythmia
Abnormal rhythm of heart
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What is AFib
Atria beat irregularly
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What is VFib
Ventricles beat irregularly
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Tachycardia
Abnormal condition of fast heart rate
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Bradycardia
Abnormal condition of slow heart rate
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What is the cardiac conduction system
The network of nodes cells and signals that control your heartbeat
82
Function of cardiac conduction system
To generate electrical signals that travel through the heart and cause different parts of the heart to expand and contract
83
Structure of SA node
A collection of specialised pacemaker cells
84
Location SA node
Upper wall of RA
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Function of SA node
To generate electrical impulses that stimulate the heart muscle to contract.
Triggers atrial systole
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Structure AV node
Collection of specialised pacemaker cells
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Location AV node
Between RA and RV
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Function of AV node
To conduct electrical impulses from the atrium to the ventricles of the heart, controlling HR
To regulate the speed of electrical impulses through heart to allow for ventricles to fill
89
Structure of Bundle of HIS
Specialised conductive cells in the interventricular septum
90
Location bundle of HIS
Connects the AV node and the R+L bundle branches of the septum
91
Function of bundle of HIS
To transmit electrical signals from the AV node to the bundle branches
92
Structure of purkinje fibres
Specialised conductive cells
93
Location of purkinje fibres
Myocardium of both ventricular walls
94
Function of purkinje fibres
To trigger ventricular systole
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Sympathetic nervous system
Increases firing rate of the SA node-> more electrical impulses generated-> inc. HR
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Parasympathetic nervous system
Decreases firing rate of SA node-> dec. HR
97
If more electrical impulses are generated, what happens to HR
HR increases
98
What is CHD/CAD
Blockage of coronary arteries (often due to athersclerosis)
99
Complete blockage of coronary arteries may lead to
MI
100
Partial blockage of coronary arteries may lead to
Angina
101
What is angina
Chest pain due to lack of oxygen and blood to the cardiac muscle
102
Tx for CAD/CHD
CABG
103
CAD/CHD risk factors
Smoking
High BMI
Stress
104
How is smoking a risk factor of CAD/CHD
Increases rate of athersclerosis
105
How is high BMI a risk factor of CAD/CHD
Increases strain on heart/ inc. BP
106
How is stress a risk factor of CAD/CHD
Chronic exposure to stress hormones e.g cortisol-> inc. BP/ weight gain
107
How to prevent high BMI
Exercise regularly
Eat a diet low in salt and low in sat fat
108
How to reduce stress
Seek support to manage stress levels
See a psychologist
109
How to maintain a healthy cardiovascular system
Exercise regularly
Healthy eating
Smoking
110
How does exercising regularly lead to a healthy CVS
Strengthens cardiac muscle, lowers BP-> Dec. strain on heart
111
Why is BP important
Gives an indication of heart function/ health
Safety
Necessary to circulate blood around whole body
112
BP normal range for newborn
60-80/ 30-60
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BP WNL toddler
90-100/ 50-65
114
BP WNL school age
95-110/ 55-70
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BP WNL adolescent
110-120/ 60-80
116
BP WNL adult
110-140/60-90
117
Hypertension health risks
Inc. strain on heart-> heart work overtime-> inc. heart failure/ MI
Rupture blood vessels-> haemorrhage/stroke
Kidney failure
118
Hypotension health risks
Dizziness
Falls
119
Systolic BP
Measures pressure of arteries when heart muscle contracts and pumps blood
120
Diastolic BP
Measures pressure of arteries when heart muscle relaxes and refills with blood
121
Factors affecting BP
Blood volume, hydration, age, exercise, stress, gender
122
What happens to BP if low blood volume
Dec. blood volume-> Dec. blood circulating-> Dec. BP
123
What happens to BP if dehydrated
Dehyrdration-> inc. blood viscosity-> inc. BP
124
What happens to BP as age increases
As age inc., BP inc
125
Do females or males have lower BP
Females
126
Suggest why hypoxia may stimulate inc. BP
Low o2-> inc need for o2 around body-> inc. blood flow around body to transport o2 around body-> inc. SV-> inc. BP
127
How does vasoconstriction inc. BP
Dec. lumen size-> inc. resistance to force blood through-> inc. BP
128
What are chemoreceptors
Receptors that detect levels of o2, co2, chemical signals
129
Location of chemoreceptors
In aorta and carotid arteries
130
What do chemoreceptors do in response to low BP
Stimulus: inc. blood levels of co2/ Dec. blood levels of o2 or low pH
Receptor: chemoreceptor detects change
Co-coordinator: cardio regulatory and vasomotor centre transmit info to CNS which engages body responses to restore homeostasis
Response: CVS inc. HR +vasoconstriction
—> INCREASED BP
131
Where is the vasomotor centre found
In brainstem
132
Baroreceptor reflex in response to low BP
Homeostasis disturbed-> baroreceptor inhibited-> vasomotor centre + cardioacceleratory centre stimulated/cardioinhibitory centre inhibited-> inc. Q, HR, SV/ vasoconstriction occurs-> homeostasis restored + BP rises to WNL
133
Baroreceptor reflex in response to high BP
Homeostasis disturbed-> baroreceptor stimulated-> cardioinhibitory centers stimulated/ cardioacceleratory and vasomotor centres inhibited-> Dec. Q, HR, SV/ vasodilation occurs-> homeostasis restored + BP decreases to WNL
134
Does low blood pressure result in vasoconstriction or vasodilation to increase BP to WNL
Vasoconstriction
135
Does high blood pressure result in vasoconstriction or vasodilation to decrease BP to WNL
Vasodilation
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137
138
Pacemaker of the heart
Sa node
139
Ways to manage low blood pressure
Increase water intake-> increase blood volume-> increase BP
Increase physical activity to inc. strength of heart-> inc. volume of blood pumped per beat
Increase salt intake/appropriate salt intake
Decrease stress
140
Considerations to make when moving patient to prevent further injury
Transport with support
Wheelchair
Not stand up too quickly
