Module 9 - Cardiovascular System Flashcards
1
Q
What is the function of the cardiovascular system?
A
Transport
2
Q
What is blood? What are blood vessels for? What does the heart do?
A
- blood is the agent of transport
- blood vessels are the tubular structures through which blood flows
- the heart pumps blood
3
Q
What are the 3 functions of blood?
A
- Transportation
- oxygen, carbon dioxide, nutrients, wastes, water, hormones, etc - regulation
- pH, body temperature, and water content of cells - protection
- clotting to prevent blood loss
- white blood cells attack microorganisms
4
Q
What are the 6 characteristics of blood?
A
- specialized connective tissue
- temperature of 36.9 degrees celsius (average)
- pH of 7.35 to 7.45
- 8% of body weight
- females have around 4-5 L
- males have around 5-6 L
5
Q
What is the composition of blood?
A
- Plasma
- 55% of blood volume
- ~90% water and proteins, ions, gases, nutrients, etc - formed elements
- 45% of blood volume
- red blood cells, white blood cells, and platelets
6
Q
What are the 3 blood proteins? What are their functions?
A
- albumin
- principle role in maintaining osmotic pressure - globulins
- function as transport proteins
- includes antibodies - fibrinogen
- involved in clotting
7
Q
What are the 3 formed elements of blood?
A
- erythrocytes (red blood cells)
- leukocytes (white blood cells)
- neutrophils
- eosinophils
- basophils
- T & B lymphocytes
- monocytes - thrombocytes (platelets)
8
Q
What is hematopoiesis?
A
hematopoiesis is the process in which blood cells are formed -occurs in the red bone marrow -occurs mainly in: vertebrae ribs sternum pelvic bones proximal femur/humerus skull
9
Q
Red bone marrow contains _______ which are capable of self-renewal
A
STEM CELLS
10
Q
stem cells proliferate by ______ and _________ to become all types of blood cells
A
MITOSIS, DIFFERENTIATE
11
Q
What are erythrocytes? What is their function? What is their shape? What is their lifespan?
A
red blood cells or RBCs
- function in O2 and CO2 transport between the lungs and body tissues
- no nucleus or organelles (more space for O2)
- biconcave shape (more surface area)
- short lifespan of ~120 days
12
Q
What is hemoglobin? What is its function? What is it composed of?
A
Hemoglobin or Hb is an iron-containing protein found in RBCs
- binds O2 and CO2 for transport
- composed of 4 GLOBINS (polypeptides) each containing a central HEME molecule
- each Hb binds 4 O2 molecules
- ~300 million Hb/RBC –> able to carry 100x more O2 than plasma alone
13
Q
What is erythropoiesis? How does it work?
A
erythropoeisis is the process in which RBCs are synthesized
- RBC precursor cells in the bone marrow fill with hemoglobin and squeeze out their nucleus to form a reticulocyte
- reticulocytes are released into the circulation where they compete their maturation into RBCs
- ~2 million RBCs produced/second
- What is the consequence of a lack of a nucleus?
14
Q
What is erythropoietin?
A
erythropoietin or EPO is the hormone secreted by the kidney in response to low blood O2 levels (=hypoxia)
- binds to specific receptors on RBC precursor cells in red bone marrow
- functions to accelerate erythropoiesis
- what situations would stimulate erythropoiesis?
15
Q
What is the fate of RBCs?
A
- RBCs circulate for ~120 days
- aged or damaged RBCs are taken up by macrophages of the spleen (also liver and bone marrow)
- products of hemoglobin breakdown:
- iron and amino acids are recycled
- bilirubin is metabolized by the liver –> bile production
16
Q
What are the 2 measures of RBC production?
A
- reticulocyte count
- measures the rate of erythropoiesis
- ~1-2% of red blood cells - hematocrit
- measures the percentage of red blood cells in blood
- males ~47%
- females ~42%
When would these values increase or decrease?
17
Q
What are leukocytes? What are their functions?
A
leukocytes are white blood cels or WBC
- generally function in protection (phagocytosis and immune response)
- cells contain a nucleus
- classified as
1. granular (granules contain enzymes and other substances)
2. agranular
18
Q
What are the 3 granular leukocytes? What do they do?
A
- neutrophils
- most numerous WBC
- fast-acting phagocytic cells
- effective in the defense against bacterial infections - eosinophils
- involved in allergic reactions
- effective in combating parasitic infections - basophils
- release histamine and other factors which contribute to inflammation
19
Q
What are the 2 agranular leukocytes? What do they do?
A
- monocytes
- largest WBC
- phagocytic cells involved in the defense against microorganisms in the blood
- called macrophages when found in tissues - lymphocytes
- 2nd most numerous WBC
- important cells of the adaptive immune response
- B lymphocytes (B cells) produce antibodies that inactivate antigens
- T lymphocytes (T cells) directly attack infected and tumour cells
20
Q
What are platelets? What is their function?
A
small, disc-shaped cell fragments
- no nucleus
- synthesis occurs in bone marrow when megakaryocytes break apart
- 70% circulate free in blood; remainder are stored in the spleen
- function in clotting
- life span of 5-9 days
21
Q
What are the 3 steps in haemostasis? What is it?
A
Haemostasis is the response of damaged blood vessels to stop bleeding
- Vascular spasm
- smooth muscle contracts, causing vasoconstriction and stopping bleeding temporarily (~30 mins) - Platelet plug formation
- injury to lining of vessel exposes collagen fibres; platelets adhere
- platelets release chemicals that make nearby platelets sticky; platelet plug forms - Coagulation
- fibrin forms a mesh that traps red blood cells and platelets, forming the blood clot
22
Q
what are the 3 disorders of haemostasis?
A
- thrombus
- blood clot in an unbroken blood vessel
- formed from platelets adhering to sites of inflammation or atherosclerosis - embolus
- any piece of cell debris carried by the blood flow
- e.g thrombus, air bubble, fat droplet, endothelium - embolism
- situation when an embolus migrates from one part of the body and causes blockage of a blood vessel in another part of the body
23
Q
What is the cardiovascular system?
A
Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. the heart pumps blood
24
Q
How does the heart and circulation work?
A
The heart is the pump, arteries take oxygenated blood away from the heart to the tissues of the body, then deoxygenated blood is carried back to the heart from the veins
25
The heart is really two pumps. What is the difference between the left and right side of the heart?
The right side supplies the lungs -- the PULMONARY CIRCULATION
The left side supplies all tissues and organs -- THE SYSTEMIC CIRCULATION
26
Where is the heart located? What is the apex and the base?
The heart is located in the thoracic cavity between the two lungs
it's 2/3 to the left of the midline
the apex is the INFERIOR tip
the base is the SUPERIOR part
27
What two parts make up the pericardium? and what are their functions?
1. fibrous pericardium: prevents overstretching and protects and anchors the heart
2. serous pericardium: double layer (parietal and visceral)
- paricardial fluid between layers allows frictionless movement
28
What are the three layers of the heart wall?
1. endocardium - simple squamous epithelium
2. myocardium - cardiac muscle
3. epicardium - visceral layer of the serous pericardium
29
What is cardiac muscle?
it is INVOLUNTARY, STRIATED and BRANCHED
30
How are cardiac muscle cells joined? What do they contain? What is their function?
- cardiac muscle cells are joined by intercalated disks
- they contain desmosomes (physically join cells) and gap junctions (allow ion flow between cells)
- allow electrical impulses to spread quickly and the heart to contract as a whole
31
What are the different heart chambers and what are their functions?
```
Right and left ATRIA (singular = atrium)
-collecting chambers
-receive venous blood
Right and left VENTRICLES
-pumping chambers
-eject arterial blood
divided by interventricular septum
```
32
What are the 5 different GREAT vessels and what do they do?
ARTERIES (leaving the heart)
-aorta --> systemic circulation
-pulmonary trunk --> pulmonary circulation
VEINS (returning to the heart)
-inferior vena cava --> drains the lower body
-superior vena cava --> drains the upper body
-pulmonary veins --> carries oxygenated blood to the heart
33
What are the 4 heart valves?
two ATRIOVENTRICULAR VALVES
-tricuspid valve --> between right atrium and right ventricule
-bicuspid valve --> (mitral valve) between left atrium and left ventricle
two SEMILUNAR VALVES
-pulmonary valve --> between the right ventricle and pulmonary trunk
-aortic valve --> between the left ventricle and the aorta
34
What are the 2 functions of the heart valves? How do they work? What does the pressure change depend on?
1. allow the forward flow of blood when open
2. prevent the backflow of blood when closed
heart valves open and close in response to changes in pressure between heart chambers and the flow of blood
pressure changes depending on:
- the filling of blood
- heart contraction
35
What are the atrioventricular valves? How do they work?
-AV valve cusps (edges) are anchored to papillary muscles of the myocardium by the chordae tendinae
-the chordae tendinae and papillary muscles keep the leaflets stable to prevent blood from flowing backward.
once filled with blood, the AV valves resemble tiny parachutes with the chordae tendinae acting as the strings
36
What are pacemaker cells?
-specialized cells that spontaneously and rhythmically generate action potentials that result in cardiac muscle contraction
(electrical conduction system of the heart)
37
What is the sinoatrial (SA) node?
-pacemaker of the heart
-located in the right atrium
-has an intrinsic rate of ~100 beats/min
regulated by the autonomic nervous system such that heart rate is ~75 beats/min at rest
(electrical conduction system of the heart)
38
How does the conduction system of the heart work?
- action potentials generated by the SA node spread to the rest of the heart via an electrical conduction system
- cardiac muscle cells are stimulated to contract as the action potential travels through this system
39
What is the route of the conduction system of the heart from start to finish?
1. SA node (initiates action potential)
2. AV node spreads to both atria (simultaneously contract)
3. travels down the interventricular septum via the AV bundles (bundle of his)
4. splits into left and right bundle branches
5. ends at the purkinje fibres (supply the ventricular myocardium)
40
What is the cardiac cycle? what is diastole and systole? What happens to the atria and ventricles during the cardiac cycle?
the cardiac cycle is all events associated with one heart beat
1. diastole: the relaxation phase of the cycle
2. systole: the contraction phase of the cycle
during the cardiac cycle, both atria contract while the ventricles relax and vice versa
41
What are the three phases of the cardiac cycle?
1. relaxation
2. atrial systole
3. ventricular systole
42
Blood flows through left and right sides ___________ as the heart _________
-simultaneously, contracts
43
The heart pumps about 5 litres of blood each minute at rest for each circuit since they're continuous. This is called the cardiac _______
cardiac output
44
What are the three measurements of heart function? What do they measure?
1. cardiac output = the volume of blood pumped by the heart each minute
2. stroke volume = the volume of blood ejected during each heart beat
3. heart rate = the number of beats per minute
calculating cardiac output:
cardiac output = heart rate x stroke volume
=5L/min at rest
can increase up to 5-6x in strenuous exercise
45
What are the 10 steps of blood flow through the heart?
1. right atrium (deoxygenated blood) flows through the tricuspid valve to the
2. right ventricle which then flows through the pulmonary valve to the
3. pulmonary trunk and pulmonary arteries to the
4. pulmonary capillaries, where the blood loses the CO2 and gains O2 then it flows to the
5. pulmonary veins to the
6. left atrium then flows through the bicuspid valve to the
7. left ventricle then flows through the aortic valve to the
8. aorta and systemic arteries which then flow to the
9. systemic capillaries where the blood loses O2 and gains CO2, and then it flows to the
10. superior vena cava, inferior vena cava, and coronary sinus to the 1. right atrium again
46
Which nerves function in regulation of heart rate? how?
The vagus nerve (parasympathetic) decreases heart rate
| the sympathetic cardiac nerves increases heart rate and force of contraction
47
What are the 3 blood vessel systems? how do they work?
1. arterial system:
- branching system
- carries blood away from the heart
2. venous system:
- converging system
- carries blood back to the heart
3. capillary system:
- carries blood from arterial to venous systems
- thin walls allow exchange between blood and tissues
48
What are the 3 blood vessel wall structures? What are they made of?
1. inner layer
- endothelium, basement membrane, elastic fibres
2. middle layer
- smooth muscle, elastic fibres
3. outer layer
- collagen fibres
49
Contraction or relaxation of smooth muscle in the middle layer changes the lumen diameter to _______ blood flow. What are vasoconstriction and vasodilation?
regulate
vasoconstriction --> smooth muscle contracts
vasodilation --> smooth muscle relaxes
50
What is the organization of blood vessels?
Arterial system: aorta, arteries, arterioles
Venous system: vena cava, veins, venules
Heart:
Capillaries:
51
What are elastic tissue? What is its function?
Elastic tissue allows arteries (i.e. aorta and pulmonary artery) to stretch and recoil
a) elastic aorta and arteries stretch during ventricular contraction
b) elastic aorta and arteries recoil during ventricular relaxation
52
What are arterioles? What is their function? What do they consist of?
- arterioles deliver blood to tissue capillaries
- consist of a single layer of endothelium covered by a few smooth muscle fibres
- along with precapillary sphincters, they regulate blood flow into capillaries
53
What are capillaries? what is their function? What are they composed of?
- small blood vessels that connect arterioles to venules
- composed of single layer of endothelial cells and a basement membrane
- function to permit the exchange of gases, nutrients, and wastes between the blood and tissue cells
54
What are venous valves?
- veins are low pressure vessels
- movement of blood against gravity, from the extremeties to the heart requires skeletal muscle contraction
- valves in the veins prevent the backflow of blood
55
What supplies blood to the actual heart muscle?
Right and Left coronary arteries
56
What is blood pressure? What are the two types of BP?
blood flows from regions of higher to lower blood pressure
-blood pressure BP is the pressure exerted by the blood on the walls of blood vessels
-systolic BP is the arterial pressure during systole
-diastolic BP is the arterial pressure during diastole
BP is highest in the aorta at about 120mmHg in systole dropping to 70mmHg in diastole (between contractions)
57
How does the regulation of blood pressure work?
1. baroreceptors in the aorta and carotid arteries detect changes in blood pressure
2. sends information via sensory nerves to the cardiovascular control centre
3. activation of motor neurons of the sympathetic NS
- excite the SA node (>heartrate) and atrial and ventricular muscle cells (>force of contraction)
- excite smooth muscle of blood vessels --> vasoconstriction (>BP)
4. activation of motor neurons of the parasympathetic NS
- inhibit the SA node (
vasodilation (
vasodilation (
