Heart Flashcards
1
Q
Blood vascular system
A
Closed, continuous supply and drainage
2
Q
Lymphatic vascular system
A
Open-entry, one-way drainage system
3
Q
Supply situated…
A
Avoid damage
Deep and on the flexor aspect of limbs
4
Q
Heart shape
A
Blunt, cone shape
Apex and base
5
Q
Point of max impulse
A
Midclavicular line b/w 5/6 rib
6
Q
Heart positioning
A
Rotated to left
Base tilted posterior
Right ventricle to sternum
7
Q
Layers of heart
A
Epicardium
Myocardium
Endocardium
8
Q
Endocardium structure
A
Simple squamous epithelium
Loose irregular FCT
Small blood vessels
Punkinje fibers
9
Q
FCT
A
Fibrous connective tissue
10
Q
Endocardium strength
A
Different orientation of FCT
11
Q
Myocardium (left)
A
1.5 cm x3 thicker vs right
Supply systemic circuit
Long distance = greater force
12
Q
Myocardium (right)
A
0.5 cm
Supply pulmonary circuit
13
Q
Epicardium
A
Viscaral pericardium
Blood vessels
Loose irregular FCT
Adipose
14
Q
Visceral pericardium is
A
part of the pericardium fused with epicardium
15
Q
Pericardium function
A
Sack that surrounds the heart
Lubricated, prevents roughing and friction
16
Q
Pericardium layers
A
Fibrous pericardium
Serous pericardium
17
Q
Serous pericardium layers
A
Parietal - outer
Visceral - inner (epicardium)
Pericardial cavity
18
Q
Fibrous pericardium
A
Dense irregular FCT
19
Q
Atrioventricular valves
A
Right - tricuspid valve
Left - bicuspid valve
20
Q
Chordae tendineae
A
During systole
Attached to free edge of AV leaflets
Prevents prolapsing into atrium chamber
21
Q
Papillary muscle
A
Systole
Tension on leaflet before chamber fills
Controlled closing
22
Q
Semilunar valves
A
Pulmonary and aortic valve
3 cusps
23
Q
Cardiomyocytes appearance
A
Straited Short, irregular branched sarcomeres 1 central nucleus per cell Interconnected via intercalated disks 8 - 10 micron (um)
24
Q
Cardiomyocytes function
A
Beating of heart
Best gas exchange
20% mitochondria cell vol
25
Cardiomyocytes gas exchange
RBC travel in single file
| Limiting distance b/w capillaries and muscle cell
26
ICDS
Adhesion belt
Desomosome
Gap junction
27
Adhesion belt
Actin to actin via transmembrane proteins
| Physical propagation
28
Desmosomes
Cytokeratin to cytokeratin (flexible skeleton inside)
| Perpendicular to force
29
Gap junction
B/w cells (level with mitochondria)
Electrochemical communication
Synchronise cells to function together
30
Skeletal muscle appearance
Nucleus pushed to periperal
2% mitchondria
No ICDs
31
Punkinje cells appearance
Started as contractile cardiac cell, to communicating cell
Central nucleus
1% cardiac cells
32
Punkinje cells function
Increase energy - mitochondria/glycogen
| Communicating - many gap junctions
33
Blood vessels layers
Tunica Intima
Tunica Media
Tunica Adventitia
34
Tunica Intima layers
Endothelium
Sub-endothelium
Internal elastic lamina (IEL)
35
Endothelium
Simple squamous epithelium
Lines lumen
Delicate
36
Sub-endothelium
Loose FCT
| Support endothelium
37
Internal elastic lamina
Condensed elastic tissue
Well developed in arteries
Stores energy
Dampens pressure
38
Tunica Media
Smooth muscle
Connective tissue - elastin, collagen
Thickness proportional diameter, b.p
39
Tunica Adventitia
```
Loose FCT (high collagen, some elastin)
Contains vasa vasorum, lymphatics, autonomic nerves
```
40
Vasa vasorum
Supply nutrients to blood vessel wall
41
Veins features
Irregular, flattened
Large lumen, thin walls
Venous valves
Large vol, low pressure
42
Veins function
Capacitance vessel - uptake extra blood
43
Veins layers
Tunica intima, media, adventitia
44
Veins tunica media
```
Thinner vs arteries
Smooth muscles (2 layers)
```
45
Veins tunica adventitia
Thickest layer
| Diameter limiting - stops uptake of too much blood
46
Venous valves function
Stop backflow of blood
47
Venous reflex
Faulty valves
48
Capillaries structure
Very thin walls
Large CSA
Slow, smooth blood flow
49
Precapillary sphincters
Smooth muscle cells
Involuntary
Regulate flow through shunt (restrict side branches)
50
Continuous capillaries
Common
8 - 10 microns (um)
Continuous basement membrane
51
Basal laminar
Stick cell to underlying of tissue
52
Fenestrated capillaries
Small holes, too small for RBC, etc...
Continuous basement membrane
8 - 10 microns (um)
53
Sinusoidal
30 - 40 microns ( 3 - 4 RBC)
Incomplete basement membrane, intercellular gap (gas exchange)
Force cells against walls (not too leaky)
54
Lymph vascular system function
Drain excess fluid from tissue and return to blood
Activate immune response
Absorbs fat from intestine
55
Lymphatic vessels structure
Large, thin walls
No RBC
Valves
Porous
56
Draining in small intestines
Lacteals drain fat-laden lymph into cisterna chyli
57
Left side and bottom half of right lymph channel
Lymphatic collecting vessels
Thoracic duct
Left subclavian vein
58
Upper right lymph channel
Right lymphatic duct
| Right subclavian vein
59
Cardiovascular system
```
Unidirectional
In series
2 circuits
Arterial blood from heart
Venous blood to heart
```
60
Pulmonary circuit
Arteries deoxygenated
| Veins oxygenated
61
Systemic circuit
Arteries oxygenated
| Veins deoxygenated
62
Contraction and Relaxation caused by
Ca2+ = cross-bridges = force
| All myocytes activated with each heartbeat
63
Diastole
Relaxation
64
Systole
Contraction
65
Systolic b.p
High
| 120
66
Diastolic b.p
Low
| 80
67
Pulse pressure
Difference b/w systolic and diastolic
68
Mean b.p
Av pressure during cardiac cycle
| Below mid-way point (more time in diastole)
69
Systemic
Measured, higher vs pulmonary
70
Hypertension
High b.p
71
Hypotension
Low b.p
72
Flow =
Change in pressure/Resistance
73
Electrical cells
1%
'Pale' striated appearence
Low actin and myosin
Rapid
74
Contractile cells
99%
Striated appearance
High actin and myosin
75
A.P propagation
Depolarisation at SAN
| Spread to adjacent cells via gap junctions from conduction to contractile
76
Gap junction where
Conduction pathway
B/w electrical and contractile
B/w contractile
77
Benefit of gap junction
Increase speed of impulse
| All cardiac cell acts as one - functional syncytium
78
Pacemaker
SA node
| Continuously independently send out electrical signal to pump heart
79
AV node function
Holds signal from SA node
| Ensure atria contracts & builds pressure
80
Why do Punkinje fibres move up sides of heart
Most efficient way for moving blood from bottom to top
81
Depolarization
Electrical change
| Signal arrives
82
Repolarization
Signal moved through
| Returns to psition before signal
83
Lubb
AV valves close
84
Dupp
Semilunar valves close
85
MAP =
CO x TPR
86
CO =
SV x HR
87
Homeostasis b.p how?
Brain - pace of heartbeat
Via brainstem
Afferent input - CNS & 'periphery'
Efferent output - Heart & blood vessels
88
What and where are baroreceptors?
B.p sensors
Aorta and carotid artery in neck
Walls of vessels
89
How does baroreceptors sense change in b.p?
Stretch
Normally constant signalling
Drop in stretch = less signals
Increase in stretch = more signals
90
Decrease b.p
Parasympathetic
Decrease heart rate
SA node - slow down
AV node - longer pauses
91
Parasympathetic pathway (b.p)
Medulla oblongata
Vagua nerve
Heart
92
Increase b.p
```
Sympathetic
Increase heart rate and force of contraction
SA - faster
AV - shorter
Punkinje and myocytes - stronger
```
93
Sympathetic pathway (b.p)
```
Medulla oblongata
Spinal cord
Sympathetic cardiac nerve
Ganglion
Heart
```
94
Distribution of cardiac output
Parallel
| Varies with exercise
95
With exercise
Brain constant
Increase: heart, skin, skeletal muscle
Decrease: kidney, GI tract, other tissues
96
Exercise MAP
CO increase, TPR decrease
97
TPR controlled
Arterioles
| R = 1/r^4
98
Rule of 16
Resistance of flow changes by a factor of 16
99
Vasodiluation
Smooth muscle relax
| Increase vessel
100
Vasoconstriction
Narrow lumen
101
How blood flow controlled
High pressure
| Greater range and control of change in flow
102
Compliance
Extent to which a vessel allows deformation in response to applied force
103
Need for extra blood?
Reduce lose of blood from system due to injury
104
Venoconstriction
Restore arterial blood
105
Arteries compliance
Low
| Low vol change under high pressure
106
Veins compliance
High
| High vol change under low pressure change
107
Compliance equation
Change in vol/change in pressure
108
Venous valves
Even distribution
| Unidirectional
109
Skeletal muscle tone
Stiffens veins
| Contractions increase 'venous return' to heart and SV
110
Starling's Law of the Heart
More stretched musclefibres before contraction, the stronger the contraction will be
111
% of blood in veins
2/3
112
Key function of blood
Transport
Immune
Coagulation
113
Transport in
O2, H2O, nutrients
Ions
Hormones
114
Tranport out
CO2, waste products
| Heat
115
Immune
Fight infection
| WBC
116
Coagulation
Prevent bleeding and pathogen entering body
| Platelets and 'coagulation factors'
117
Blood composition
Plasma 55%
| Formed elements 45%
118
Hematopoiesis
Formation of blood cells
| Initiated in red bone marrow
119
Hemocytoblasts
Progenitors for all blood cells
120
Erythropoietin (EPO)
Stimulates RBC formation
121
Erythropoiesis
Generation of RBC
122
RBC physical characteristics
Biconcave disc
Large SA:V
Flexibility for movment through narrow capillaries
1/3 - hemoglobin
123
Hematocrit
% of RBC
124
Anemic
Not enough RBC
125
Polycythemic
Too much RBC
126
Training in high altitudes
Decrease RBC
Kidney release EPO
Increases RBC, greater oxygen capacity
127
EPO augmented by
Testosterone
