Transcript PowerPoint to accompany - Phlebotomy Career Training

Cardiovascular System
1
Size of Heart
Average Size of Heart
• 14 cm long
• 9 cm wide
2
Location of Heart
• posterior to sternum
• medial to lungs
• anterior to vertebral column
• base lies beneath 2nd rib
• apex at 5th intercostal space
• lies upon diaphragm
3
Coverings of Heart
4
Wall of the Heart
5
Wall of the Heart
6
Heart Chambers
Right Atrium
• receives blood from
• inferior vena cava
• superior vena cava
• coronary sinus
Right Ventricle
• receives blood from
right atrium
Left Atrium
• receives blood from
pulmonary veins
Left Ventricle
• receives blood from
left atrium
7
Heart Valves
8
Coronal Sections of Heart
9
Heart Valves
Tricuspid Valve
Pulmonary and Aortic Valve
10
Skeleton of Heart
• fibrous rings to which the heart valves are attached
11
Path of Blood
Through the Heart
12
Path of Blood
Through the Heart
13
Blood Supply to Heart
14
Blood Supply to Heart
15
Angiogram of Coronary
Arteries
16
Heart Actions
Atrial Systole/Ventricular Diastole
Atrial Diastole/Ventricular Systole
17
Cardiac Cycle
Atrial Systole/Ventricular Diastole
• blood flows passively into ventricles
• remaining 30% of blood pushed into ventricles
• A-V valves open/semilunar valves close
• ventricles relaxed
• ventricular pressure increases
18
Cardiac Cycle
Ventricular Systole/Atrial diastole
• A-V valves close
• chordae tendinae prevent cusps of valves from
bulging too far into atria
• atria relaxed
• blood flows into atria
• ventricular pressure increases and opens semilunar
valves
• blood flows into pulmonary trunk and aorta
19
Heart Sounds
Lubb
• first heart sound
• occurs during ventricular systole
• A-V valves closing
Dupp
• second heart sound
• occurs during ventricular diastole
• pulmonary and aortic semilunar valves closing
Murmur – abnormal heart sound
20
Heart Sounds
21
Cardiac Muscle Fibers
Cardiac muscle fibers form a functional
syncytium
• group of cells that function as a unit
• atrial syncytium
• ventricular syncytium
22
Cardiac Conduction System
23
Cardiac Conduction System
24
Muscle Fibers in
Ventricular Walls
25
Electrocardiogram
• recording of electrical changes that occur in the myocardium
• used to assess heart’s ability to conduct impulses
P wave – atrial depolarization
QRS wave – ventricular depolarization
T wave – ventricular repolarization
26
Electrocardiogram
27
Electrocardiogram
A prolonged QRS complex may result from damage to the A-V
bundle fibers
28
Cardiac Cycle
29
Regulation of Cardiac Cycle
Autonomic nerve impulses alter the
activities of the S-A and A-V nodes
30
Regulation of Cardiac Cycle
Additional Factors that Influence HR
• physical exercise
• body temperature
• concentration of various ions
• potassium
• calcium
• parasympathetic impulses decrease heart action
• sympathetic impulses increase heart action
• cardiac center regulates autonomic impulses to the heart
31
Blood Vessels
• arteries
• carry blood away from ventricles of heart
• arterioles
• receive blood from arteries
• carry blood to capillaries
• capillaries
• sites of exchange of substances between
blood and body cells
• venules
• receive blood from capillaries
• veins
• carry blood toward ventricle of heart
32
Arteries and Arterioles
Artery
• thick strong wall
• endothelial lining
• middle layer of smooth
muscle and elastic tissue
• outer layer of
connective tissue
• carries blood under
relatively high pressure
Arterioles
• thinner wall than
artery
• endothelial lining
• some smooth muscle
tissue
• small amount of
connective tissue
• helps control blood
flow into a capillary
33
Walls of Artery and Vein
34
Arteriole
• smallest arterioles only have a few smooth muscle fibers
• capillaries lack muscle fibers
35
Metarteriole
connects arteriole directly to venule
36
Capillaries
• smallest diameter blood vessels
• extensions of inner lining of arterioles
• walls are endothelium only
• semipermeable
• sinusoids – leaky capillaries
37
Capillary Network
38
Regulation of Capillary
Blood Flow
Precapillary
sphincters
• may close a
capillary
• respond to
needs of the cells
• low oxygen and
nutrients cause
sphincter to
relax
39
Exchange in the Capillaries
• water and other substances leave capillaries because of net outward pressure
at the capillaries’ arteriolar ends
• water enters capillaries’ venular ends because of a net inward pressure
• substances move in and out along the length of the capillaries according to
their respective concentration gradients
40
Venules and Veins
Venule
• thinner wall than arteriole
• less smooth muscle and elastic tissue than arteriole
Vein
• thinner wall than artery
• three layers to wall but middle layer is poorly developed
• some have flaplike valves
• carries blood under relatively low pressure
• serves as blood reservoir
41
Venous Valves
42
Characteristics of Blood Vessels
43
Blood Volumes in Vessels
44
Arterial Blood Pressure
Blood Pressure – force the blood exerts against the
inner walls of the blood vessels
Arterial Blood Pressure
• rises when ventricles contract
• falls when ventricles relax
• systolic pressure – maximum pressure
• diastolic pressure – minimum pressure
45
Pulse
• alternate expanding and recoiling of the arterial wall
that can be felt
46
Factors That Influence
Arterial Blood Pressure
47
Control of Blood Pressure
Controlling cardiac output and peripheral resistance
regulates blood pressure
48
Control of Blood Pressure
If blood pressure rises, baroreceptors initiate the
cardioinhibitory reflex, which lowers the blood pressure
49
Control of Blood Pressure
Dilating arterioles helps regulate blood pressure
50
Venous Blood Flow
• not a direct result of heart
action
• dependent on
• skeletal muscle
contraction
• breathing
• venoconstriction
51
Central Venous Pressure
• pressure in the right atrium
• factors that influence it alter flow of blood into
the right atrium
• affects pressure within the peripheral veins
• weakly beating heart increases central venous
pressure
• increase in central venous pressure causes blood
to back up into peripheral vein
52
Pulmonary Circuit
• consists of vessels that carry blood from the heart to the lungs
and back to the heart
53
Blood Flow Through Alveoli
• cells of alveolar wall are tightly joined together
• the high osmotic pressure of the interstitial fluid draws
water out of them
54
Systemic Circuit
• composed of vessels that lead from the heart to
all body parts (except the lungs) and back to the
heart
• includes the aorta and its branches
• includes the system of veins that return blood to
the right atrium
55
Major Vessels of Arterial
System
56
Major Blood Vessels of the
Heart
57
Principal Branches of the
Aorta
58
Abdominal Aorta and Its
Major Branches
59
Arteries to Neck, Head, and
Brain
60
Cerebral Arterial Circle
• Circle of Willis
• formed by anterior and posterior cerebral arteries, which
join the internal carotid arteries
61
Arteries to Shoulder
and Upper Limb
62
Arteries to Thoracic Wall
63
Arteries to Pelvic Region
64
Arteries to the Lower Limb
65
Major Vessels of the Venous
System
66
Major Veins of the Brain, Head
and Neck
67
Veins from the Upper Limb
and Shoulder
68
Veins That Drain the Thoracic
Wall
69
Veins That Drain the
Abdominal Viscera
70
Veins from the Abdominal Viscera:
Hepatic Portal Vein
Hepatic portal vein drains one set of capillaries
and leads to another set
71
Veins of the Lower Limb and
Pelvis
72
Life-Span Changes
• cholesterol deposition in blood vessels
• heart enlargement
• death of cardiac muscle cells
• increase in fibrous connective tissue of the heart
• increase in adipose tissue of the heart
• increase in blood pressure
• decrease in resting heart rate
73
Clinical Application
Arrhythmias
Ventricular fibrillation
• rapid, uncoordinated
depolarization of ventricles
Tachycardia
• rapid heartbeat
Atrial flutter
• rapid rate of atrial
depolarization
74