Cardiovascular System Flashcards
1
Q
Duty of blood
A
Transports everything that must be carried from one place to another, including
- Nutrients
- Oxygen
- Wastes
- Hormones
- Body heat
- Acid base and electrolyte balance
2
Q
Components of blood
A
▪ Formed elements (living cells) – 45% known as hematocrit as Erythrocytes sink to the bottom
▪ Plasma (nonliving fluid matrix) – 55%
▪ Buffy Coat (less than 1%) contains leukocytes and platelets – thin, whitish layer between the erythrocytes and plasma
3
Q
Physical characteristics of blood
A
- Sticky, opaque fluid
- Heavier and thicker than water (5 times)as blood contains solid components such as plasma proteins, electrolytes
- Color range: oxygen-rich blood is scarlet red, oxygen-poor blood is dull red or purple
- Metallic, salty taste
- Blood pH is slightly alkaline, 7.35 – 7.45 pH
- Temperature 38 degrees
- Blood viscosity contributes to blood flow resistance. Blood viscosity increases with high altitudes, decreased blood temperature and increased proportion of red blood cells
4
Q
Composition of plasma
A
90% water , 8% plasma proteins
Straw-coloured fluid
Dissolved substances (2%): nutrients, salts (electrolytes), respiratory gases, hormones, plasma proteins, waste products
electrolytes such as sodium, potassium, chloride, magnesium and calcium, maintain fluid and electrolyte balance
5
Q
Describe and name the plasma proteins
A
- Most abundant solutes in plasma
- Most are made by the liver
- 3 types – fibrinogen, albumin and globulin
- Albumin – an important blood buffer and contributes to osmotic pressure
- Fibrinogen - Clotting proteins – help to stem blood loss when a blood vessel is injured
- Globulin - Antibodies – help protect the body from pathogens
6
Q
Describe components of the formed elements
A
Each element starts as haematopoietic stem cell which morphs into another type of morph cell which turns into a blast cell. Depending on which growth factors and hormones influence them, these cells turn into either:
Erythrocytes – red blood cells (RBCs)
Leukocytes – White blood cells (WBCs)
Platelets – Cell fragments
7
Q
Explain Erythrocytes
A
Main function is to carry oxygen and carry C02 away
Difference to other blood cells –
- Anucleate (no nucleus)
- Contains few organelles, no mitochondria
- Shaped like biconcave discs – increases surface area, flexibility is increased, restricts the cell’s life span to 120 days
- 7-8 micro mm
8
Q
What is haemoglobin
A
- Binds oxygen, each can bind 4 oxygen molecules
- Transports C02 back to lungs
- Each erythrocyte has 250million haemoglobin molecules
- Normal blood contains 12-18g of haemoglobin per 100ml of blood
9
Q
Describe Leukocytes
A
- Crucial in body’s defence against disease
- Complete cells, with nucleus and organelles
- Able to move into and out of blood vessels (diapedesis)
- Respond to chemicals released by damaged tissues (known as positive chemotaxis)
- Move by amoeboid motion
- 4,800 to 10,800 WBCs per mm3 of blood, for 1 wbc there are 700 rbc
- Produce antibodies, play role in allergic reactions, inflammatory response, destroy parasites
10
Q
What are platelets
A
▪ Fragments of megakaryocytes (multinucleate cells)
Small, irregularly shaped, non-nucleated
Important in haemostasis
▪ Needed for the clotting process
▪ Normal platelet count is 300,000 platelets per mm3 of blood
11
Q
Positioning and size of heart
A
Size of a human fist, weighs less than a pound
Located in the thoracic cavity, in the inferior mediastinum
▪ Apex is directed toward left hip and rests on the diaphragm 5th rib ▪ Base points toward right shoulder
12
Q
Coverings of the heart
A
Pericardium – a double walled sac
- Fibrous pericardium is loose and superficial
- Serous membrane is deep to the fibrous pericardium and contains two layers
- Serous fluid fills the space between the layers of pericardium called the pericardial cavity
13
Q
What are the walls of the heart
A
- Epicardium ▪ Outside layer; the visceral pericardium, the coronary artery lies here
- Myocardium ▪ Middle layer ▪ Mostly cardiac muscle, 2/3 of the heart muscle, contracts
- Endocardium ▪ Inner layer known as endothelium
14
Q
What are the chambers of the heart and explain their duties
A
Atria (right and left) – superior - Receiving chambers - Assist with filling the ventricles - Blood enters under low pressure Ventricles (right and left) - Discharging chambers - Thick walled pumps of the heart - During contraction, blood is propelled into circulation
15
Q
Name the septum and their duties
A
Interatrial septum
- Separates the two atria longitudinally
Interventricular septum
- Separates the two ventricles longitudinally
16
Q
Explain the double pump
A
- Arteries carry blood away from the heart
- Veins carry blood toward the heart
Double pump - Right side works as the pulmonary circuit pump
- Left side works as the systemic circuit pump
17
Q
What is the pulmonary Circuit pump
A
▪ Blood flows from the right side of the heart to the lungs and back to the left side of the heart
▪ Blood is pumped out of right side through the pulmonary trunk, which splits into pulmonary arteries and takes oxygen-poor blood to lungs
▪ Oxygen-rich blood returns to the heart from the lungs via pulmonary veins
18
Q
What is the Systemic Circulation pump
A
▪ Oxygen-rich blood returned to the left side of the heart is pumped out into the aorta
▪ Blood circulates to systemic arteries and to all body tissues
▪ Left ventricle has thicker walls because it pumps blood to the body through the systemic circuit
▪ Oxygen-poor blood returns to the right atrium via systemic veins, which empty blood into the superior or inferior vena cava
19
Q
Explain the heart valves
A
Allow blood to flow in only one direction, to prevent backflow
▪ Atrioventricular (AV) valves—between atria and ventricles ▪ Left AV valve: bicuspid (mitral) valve ▪ Right AV valve: tricuspid valve
▪ Open during heart relaxation, when blood passively fills the chambers ▪ Closed during ventricular contraction
▪ Semilunar valves—between ventricle and artery ▪ Pulmonary semilunar valve ▪ Aortic semilunar valve
Closed during heart relaxation ▪ Open during ventricular contraction
Valves open and close in response to pressure changes in the heart
20
Q
Components of blood supply to circulatory system
A
▪ Coronary arteries (right and left) —branch from the aorta to supply the heart muscle with oxygenated blood, filled when heart is relaxed
▪ Cardiac veins—drain the myocardium of blood
▪ Coronary sinus—a large vein on the posterior of the heart; receives blood from cardiac veins
Blood empties into the right atrium via the coronary sinus
21
Q
Unifying regulatory systems are
A
- Autonomic nervous system – decrease or increase heart rate
- Intrinsic conduction system, or the nodal system
- Sets the heart rhythm ▪ Composed of special nervous tissue ▪ Ensures heart muscle depolarization in one direction only (atria to ventricles) ▪ Enforces a heart rate of 75 beats per minute
22
Q
Components of the intrinsic conduction system
A
▪ Sinoatrial (SA) node - Located in the right atrium ▪ Serves as the heart’s pacemaker
▪ Atrioventricular (AV) node is at the junction of the atria and ventricles
▪ Atrioventricular (AV) bundle (bundle of His) and bundle branches are in the interventricular septum
▪ Purkinje fibers spread within the ventricle wall muscles
23
Q
Steps of contraction coordination
A
- The sinoatrial node (SA node) starts each heartbeat
- Electrical impulses carried to left atrium
- Atria contract
- At the AV node, the impulse is delayed briefly
- Impulse travels through the AV bundle, bundle branches, and Purkinje fibers ▪ Ventricles contract; blood is ejected from the heart
24
Q
Explain Tachycardia and Bradycardia
A
▪ Tachycardia—rapid heart rate, over 100 beats per minute ▪ Bradycardia—slow heart rate, less than 60 beats per minutes
25
Explain the ECG
▪ Recording of electrical activity of the heart
Three waves –
1. P wave – small, signal depolarization, firing of sinoatrial node
2. QRS complex – depolarization of ventricles, contraction of the ventricles
3. T wave – ventricle relax, repolarization
▪ Illustrates what is happening electrically in the atria and ventricles when the depolarize (contract) and relax (repolarize)
26
What are systole and diastole
- Systole = contraction (1/3 of the cycle)
| - Diastole = relaxation (2/3 of the cycle)
27
What are the cardiac cycle steps
1. Atrial Diastole – ventricular filling
2. Atrial Systole
3. Isovolumetric contraction
4. Ventricular systole (ejection phase)
5. Isometric relaxation
28
Explain the heart sounds
▪ Often described a “lub” and “dup” sounds - Correspond with closing of heart valves
Heart murmurs are abnormal or unusual heart sounds ▪ Reflect turbulent blood flow
▪ Lub—longer, louder heart sound caused by the closing of the AV valves
▪ Dup—short, sharp heart sound caused by the closing of the semilunar valves at the end of ventricular systole
29
What is cardiac output and Stroke volume
Cardiac Output (CO)
▪ Amount of blood pumped by each side (ventricle) of the heart in 1 minute
Stroke volume (SV)
▪ Volume of blood pumped by each ventricle in one contraction (each heartbeat) ▪ About 70 ml of blood is pumped out of the left ventricle with each heartbeat
30
What is heart rate and how is it calculated
▪ Cardiac output is the product of the heart rate (HR) and the stroke volume (SV) ▪ CO = HR × SV ▪ CO = HR (75 beats/min) × SV (70 ml/beat) ▪ CO = 5250 ml/min = 5.25 L/min
31
How is stroke volume regulated
how much cardiac muscle is stretched
▪ The more the cardiac muscle is stretched, the stronger the contraction
▪ Venous return is the important factor influencing the stretch of heart muscle
32
3 Factors modifying basic heart rate
1. Neural (ANS) controls
▪ Sympathetic nervous system speeds heart rate
▪ Parasympathetic nervous system, primarily vagus nerve
fibers, slow and steady the heart rate
2. Hormones and ions
▪ Epinephrine and thyroxine speed heart rate
▪ Excess or lack of calcium, sodium, and potassium ions
also modify heart activity
3. Physical factors
▪ Age, gender, exercise, body temperature influence
heart rate
33
What are blood vessels and what are they called
Blood vessels form a closed vascular system that transports blood to the tissues and back to the heart
▪ Vessels that carry blood away from the heart - Arteries and arterioles
▪ Vessels that play a role in exchanges between tissues and blood - Capillary beds
▪ Vessels that return blood toward the heart - Venules and veins
34
Describe three tunic layers
1. Tunica intima forms a friction-reducing lining ▪ Allows blood to flow smoothly. Endothelium
2. Tunica media ▪ Smooth muscle and elastic tissue and collagen ▪ Controlled by sympathetic nervous system to dilate lumen or decrease opening. Allows blood flow to certain tissue and decreases flow to some.
3. Tunica externa forms protective outermost covering ▪ Mostly fibrous connective tissue ▪ Supports and protects the vessel
35
Describe arteries and aortas
Arteries have a heavier, stronger, stretchier tunica media than veins to withstand changes in pressure
Aortas – largest artery, leaves heart and branches into small arteries that turns into arteriole
36
Describe veins and venules
Veins have a thinner tunica media than arteries and operate under low pressure ▪ Veins also have valves to prevent backflow of blood ▪ Lumen of veins is larger than that of arteries ▪ Skeletal muscle “milks” blood in veins toward the heart
Venules form to make the largest veins, superior and inferior vena cava
37
Describe capillaries
Only one cell layer thick (tunica intima) ▪ Allow for gas exchanges between blood and tissue ▪ Form networks called capillary beds that consist of: ▪ A vascular shunt ▪ True capillaries ▪ Blood flow through a capillary bed is known as microcirculation
38
Describe True capillaries
▪ Branch off a terminal arteriole ▪ Empty directly into a postcapillary venule
39
Major arteries of Systemic circulation
Aorta - ▪ Largest artery in the body Regions:
▪ Ascending aorta—leaves the left ventricle
▪ Aortic arch—arches to the left ▪ Thoracic aorta—travels downward through the thorax ▪ Abdominal aorta—passes through the diaphragm into the abdominopelvic cavity
▪ Arterial branches of the ascending aorta - Right and left coronary arteries serve the heart
40
Arterial branches of the aortic arch
▪ Brachiocephalic trunk splits into the: ▪ Right common carotid artery ▪ Right subclavian artery
▪ Left common carotid artery splits into the: ▪ Left internal and external carotid arteries, serves the brain
▪ Left subclavian artery branches into the: ▪ Vertebral artery ▪ In the axilla, the subclavian artery becomes the axillary artery → brachial artery → radial and ulnar arteries
Digital arteries
41
Arterial branches of the thoracic aorta
▪ Intercostal arteries supply the muscles of the thorax wall
▪ Other branches of the thoracic aorta supply the:
▪ Lungs (bronchial arteries) ▪ Esophagus (esophageal arteries) ▪ Diaphragm (phrenic arteries)
42
Arteries of the head
Internal carotid artery – serves the brain
| External carotid artery – serves skin and muscles of head and neck
43
Arterial branches of the abdominal aorta
▪ Celiac trunk is the first branch of the abdominal aorta. Three branches are: 1. Left gastric artery (stomach) 2. Splenic artery (spleen) 3. Common hepatic artery (liver)
▪ Superior mesenteric artery supplies most of the small intestine and first half of the large intestine
▪ Left and right renal arteries (kidney)
▪ Left and right gonadal arteries ▪ Ovarian arteries in females serve the ovaries ▪ Testicular arteries in males serve the testes
▪ Lumbar arteries serve muscles of the abdomen and trunk
▪ Inferior mesenteric artery serves the second half of the large intestine
44
Major Veins of systemic circualtion
▪ Superior vena cava and inferior vena cava enter the right atrium of the heart
▪ Superior vena cava drains the head and arms ▪ Inferior vena cava drains the lower body
45
Veins draining into the superior vena cava
▪ Radial and ulnar veins → brachial vein → axillary vein ▪ Cephalic vein drains the lateral aspect of the arm and empties into the axillary vein ▪ Basilic vein drains the medial aspect of the arm and empties into the brachial vein ▪ Basilic and cephalic veins are joined at the median cubital vein (elbow area)
▪ Subclavian vein receives: ▪ Venous blood from the arm via the axillary vein ▪ Venous blood from skin and muscles via external jugular vein
▪ Vertebral vein drains the posterior part of the head
▪ Internal jugular vein drains the dural sinuses of the brain
▪ Left and right brachiocephalic veins receive venous blood from the: ▪ Subclavian veins ▪ Vertebral veins ▪ Internal jugular veins
▪ Brachiocephalic veins join to form the superior vena cava → right atrium of heart
▪ Azygos vein drains the thorax
46
Veins draining into the inferior vena cava
▪ Anterior and posterior tibial veins and fibial veins drain
the legs
▪ Posterior tibial vein → popliteal vein → femoral vein →
external iliac vein
▪ Great saphenous veins (longest veins of the body)
receive superficial drainage of the legs
▪ Each common iliac vein
▪ Right gonadal vein drains the right ovary in females and
right testicle in males
▪ Left gonadal vein empties into the left renal vein
▪ Left and right renal veins drain the kidneys
▪ Hepatic portal vein drains the digestive organs and
travels through the liver before it enters systemic
circulation
▪ Left and right hepatic veins drain the liver
47
Arterial supply of the brain
▪ Internal carotid come from neck and temporal bone and arteries divide into: Anterior and middle cerebral arteries - supply most of the cerebrum
▪ Vertebral arteries join once within the skull to form the basilar artery ▪ Basilar artery serves the brain stem and cerebellum.
▪ Posterior cerebral arteries form from the division of the basilar artery ▪ These arteries supply the posterior cerebrum
▪ Anterior and posterior blood supplies are united by small communicating arterial branches
48
Name the brain arteries
```
Internal carotid artery
Middle carotid artery
Anterior communicating
artery
Anterior cerebral artery
Posterior communicating
artery
Posterior cerebral artery
Basilar artery
Vertebral artery
```
49
Hepatic portal circulation
```
formed by veins
draining the digestive organs, which empty into
the hepatic portal vein
▪ Digestive organs
▪ Spleen
▪ Pancreas
```
50
Duty of hepatic portal vein
carries blood to the liver,
where it is processed before returning to systemic
circulation
51
Describe vital signs and arterial pulse
Vital signs
▪ Measurements of arterial pulse, blood pressure,
respiratory rate, and body temperature
Arterial pulse
▪ Alternate expansion and recoil of a blood vessel wall
(the pressure wave) that occurs as the heart beats
▪ Monitored at pressure points in superficial arteries,
where pulse is easily palpated
▪ Pulse averages 70 to 76 beats per minute at rest, in a
healthy person
52
Body sites where pulse is most easily palpated
```
Superficial temporal artery
Facial artery
Common carotid artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial artery
Dorsalis pedis artery
```
53
What is blood pressure
▪ The pressure the blood exerts against the inner walls of the blood vessels ▪ The force that causes blood to continue to flow in the blood vessels (in arteries supplied by aorta)
54
What is the blood pressure gradient
When the ventricles contract:
▪ Blood is forced into elastic arteries close to the heart
▪ Blood flows along a descending pressure gradient
▪ Pressure decreases in blood vessels as distance from
the heart increases
▪ Pressure is high in the arteries, lower in the capillaries,
and lowest in the veins
55
How to measure blood pressure
▪ Two arterial blood pressures are measured
▪ Systolic—pressure in the arteries at the peak of
ventricular contraction
▪ Diastolic—pressure when ventricles relax
▪ Auscultatory method is an indirect method of
measuring systemic arterial blood pressure, most often
in the brachial artery
56
What factors effect blood pressure
▪ Arterial blood pressure (BP) is directly related to
cardiac output and peripheral resistance
▪ Cardiac output (CO; the amount of blood pumped out of
the left ventricle per minute)
▪ Peripheral resistance (PR; the amount of friction blood
encounters as it flows through vessels)
BP = CO × PR
57
Effects of neural factors on blood pressure
the autonomic nervous system
▪ Parasympathetic nervous system has little to no effect
on blood pressure
▪ Sympathetic nervous system promotes vasoconstriction
(narrowing of vessels), which increases blood pressure
58
Effects of renal factors on blood pressure
▪ Kidneys regulate blood pressure by altering blood
volume
▪ If blood pressure is too high, the kidneys release water
in the urine
▪ If blood pressure is too low, the kidneys release renin to
trigger formation of angiotensin II, a vasoconstrictor
▪ Angiotensin II stimulates release of aldosterone, which
enhances sodium (and water) reabsorption by kidneys
59
Effects of temperature on blood pressure
▪ Heat has a vasodilating effect
| ▪ Cold has a vasoconstricting effect
60
Effects of chemicals on blood pressure
▪ Various substances can cause increases or decreases
in blood pressure
▪ Epinephrine increases heart rate and blood pressure
61
Effects of diet on blood pressure
▪ Commonly believed that a diet low in salt, saturated
fats, and cholesterol prevents hypertension (high blood
pressure)
62
What is the normal human range for blood pressure
▪ Systolic pressure ranges from 110 to 140 mm Hg
| ▪ Diastolic pressure ranges from 70 to 80 mm Hg
63
What is hypotension
▪ Low systolic (below 100 mm Hg)
▪ Often associated with illness
▪ Acute hypotension is a warning sign for circulatory
shock
64
What is hypertension
▪ Sustained elevated arterial pressure of 140/90 mm Hg
| ▪ Warns of increased peripheral resistance
65
what are the four processes of capillary exchange of gases and nutrients
▪ Substances take various routes entering or leaving the
blood
1. Direct diffusion through membranes
2. Diffusion through intercellular clefts (gaps between
cells in the capillary wall)
3. Diffusion through pores of fenestrated capillaries
4. Transport via vesicles
66
Fluid movement out of or into a capillary depends on
| what?
1. Blood pressure forces fluid and solutes out of
capillaries
2. Osmotic pressure draws fluid into capillaries
67
Fluid pressures at capillary bed
▪ Blood pressure is higher than osmotic pressure at the
arterial end of the capillary bed
▪ Blood pressure is lower than osmotic pressure at the
venous end of the capillary bed
▪ Thus, fluid moves out of the capillary at the beginning
of the bed and is reclaimed at the opposite (venule)
end
68
Name and explain some heart diseases
```
Diseases of the arteries
▪ Aneurysms
▪ Coronary artery disease
Heart attack
▪ Myocardial infarction
Heart murmurs
▪ Caused by one of the heart valves not closing properly
Diseases ending in –itis
▪ Pericarditis
▪ Myocarditis
▪ Endocarditis
Heart failure
▪ Occurs when the heart cannot adequately pump blood
```
69
Name the arteries that supply the lower limb (8)
```
Common iliac artery
External iliac artery
Femoral artery
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Dorsalis pedis artery
Arcuate artery
```
70
Name the arteries that supply the upper limb (8)
```
Subclavian artery
Axillary artery
Brachial artery
Radial artery
Ulnar artery
Deep palmar arch
Superficial palmar arch
Digital arteries
```
71
Name the arteries of the head and trunk (12)
```
Internal carotid artery
External carotid artery
Common carotid arteries
Vertebral artery
Subclavian artery
Brachiocephalic trunk
Aortic arch
Ascending aorta
Coronary artery
Thoracic aorta
(above diaphragm)
Celiac trunk
Abdominal aorta
```
72
Name the veins of the upper limb
```
Subclavian vein
Axillary vein
Cephalic vein
Brachial vein
Basilic vein
Median cubital vein
Ulnar vein
Radial vein
Digital veins
```
73
Name veins of the lower limb
```
External iliac vein
Femoral vein
Great saphenous vein
Popliteal vein
Posterior tibial vein
Anterior tibial vein
Small saphenous vein
Dorsal venous arch
Dorsal metatarsal veins
```
74
Veins of the head and trunk
```
Dural venous sinuses
External jugular vein
Vertebral vein
Internal jugular vein
Right and left
brachiocephalic veins
Superior vena cava
Great cardiac vein
```
75
Describe cardiac contractions step - Atrial Diastole
```
1. ventricular filling
Heart is relaxed
Pressure in heart is low
Atrioventricular valves are open
Blood flows passively into the atria and into ventricles
Semilunar valves are closed
```
76
Describe cardiac contractions step - Atrial Systole
▪ Ventricles remain in diastole
▪ Atria contract
▪ Blood is forced into the ventricles to complete ventricular filling
77
Describe cardiac contractions step - Isovolumetric contraction
▪ Atrial systole ends; ventricular systole begins
▪ Intraventricular pressure rises
▪ AV valves close
▪ For a moment, the ventricles are completely closed chambers
78
Describe cardiac contractions step - Ventricular Systole
▪ Ventricles continue to contract ▪ Intraventricular pressure now surpasses the pressure in the major arteries leaving the heart ▪ Semilunar valves open ▪ Blood is ejected from the ventricles ▪ Atria are relaxed and filling with blood
79
Describe cardiac contractions step - Isometric relaxation
▪ Ventricular diastole begins
▪ Pressure falls below that in the major arteries
▪ Semilunar valves close
▪ For another moment, the ventricles are completely closed chambers
▪ When atrial pressure increases above intraventricular pressure, the AV valves open
