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Cardiovascular System

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What is included in the cardiovascular system?
heart, blood, and blood vessels
What are the functions of the cardiovascular system?
Maintains homeostasis
Transports nutrients, wastes, hormones, respiratory gases, salts, electrolytes
Protects against disease
Regulate pH
Maintain water balance
Prevents hemorrhage
Regulates temperature
Name 3 types of blood vessels.
arteries
veins
capillaries
Which blood vessels carry blood away from the heart?
arteries
Which vessels return blood to the heart?
veins
Which are the smallest vessels that exchange materials with tissue fluids?
capillaries
Do the larger blood vessels have blood vessels of their own? If so, explain why.
yes because they require oxygen and nutrients
Describe the outer layer of an arterial wall.
mostly fibrous connective
Describe the middle layer of an arterial wall.
mostly smooth muscle; thickest
Describe the inner layer of an arterial wall.
endothelium (simple squamous epithelium) with connective tissue basement membrane with elastic fibers
What are arterioles?
small arteries
How does the constriction and dilation of arterioles affect blood pressure?
the greater the number dilated, the lower the blood pressure
the fewer the number dilated, the higher the blood pressure
How thick are the walls of capillaries?
one cell thick
Are there capillary beds present in all regions of the body?
yes, almost all regions
Where are capillary beds not present?
cartilage, cornea, epidermis, epithelial
Why are capillaries a very important part of the cardiovascular system?
they connect arterioles and venules
they exchange materials with tissue fluid
Compare the wall of a vein with that of an artery. Which wall is thinner?
veins have same three layers as arteries, but middle layer poorly developed
Which wall is thinner, vein or artery?
vein
What accounts for blood flow in arteries and arterioles?
kept moving by pumping of the heart
What accounts for blood flow In veins?
due to skeletal muscle contraction
Are valves characteristic of arteries or veins?
veins
How do valves function?
allow blood to flow only in one direction and prevent back flow
What are varicose veins?
blood pooling in veins causing them to enlarge
At any time, how much of the blood is in veins?
more than half
Why is it said that the veins act as a reservoir?
because the veins hold the majority of the body's blood
What percentage of blood is found in veins?
70%
How large is the human heart?
the size of the human fist
What is the myocardium?
the major portion of the heart made of cardiac muscle tissue
Describe the myocardium's tissue makeup.
branched and tightly joined to one another
What is the pericardium?
where the heart lies
As a serous membrane, what would the pericardium's tissue makeup be?
connective and endothelial tissue
What is the epicardium?
outer protective layer of the heart
Describe the epicardium's tissue makeup.
cardiac muscle
What is the endocardium?
innermost layer of heart tissue that lines the cavities and valves of the heart
Describe the endocardium's tissue makeup.
loose connective tissue and simple squamous epithelial tissue
How many chambers does the human heart have?
four
Name and describe the upper chambers.
atria (upper 2 chambers) are weaker and sends blood to lower chambers
Name and describe the lower chambers.
ventricles (lower 2 chambers) are stronger with thicker walls. R vent sends blood to lungs. L vent sends blood to rest of body
What divides the heart internally?
septum
The heart valves permit only ___-way flow of blood.
one
What are atrioventricular valves?
allow blood to pass from the atria to the ventricles, closing tight to block leakage of blood back into the atria.
What are semilunar valves?
open to let blood pass out of the ventricles
Which specific valve is between the right atrium and the right ventricle?
tricuspid
Which specific valve is between the left atrium and the left ventricle?
bicuspid
Which valve is between the right ventricle and the pulmonary trunk?
semilunar valves
Which valve is between the left ventricle and the aorta?
aortic valve
What are the chordae tendineae?
strong fibrous strings that prevent the AV valve from inverting when heart contracts
Trace the route of blood through the heart.
...
Why is the heart called a double pump?
because the right ventricle sends blood into the lungs and the left ventricle sends blood into the rest of the body
Why are the walls of the left ventricle thicker than those of the right ventricle?
because it has a harder job of pumping blood to the entire body
In what vessel is blood pressure the greatest?
aorta
What is a cardiac cycle?
heartbeat
What does a heartbeat consist of?
systole (contraction) and diastole (relaxation) of the heart muscle
How many times a minute does the average adult heart beat?
60-80 beats
How long does each heartbeat last?
.85 sec
What is systole?
contraction of the heart muscle (atria & ventricles)
What is diastole?
relaxation of the heart muscle (atria and ventricles)
The atria have a short ______, followed by the longer and stronger ventricular systole.
systole
What accounts for the sound of the heartbeat, "lub-dub"?
heartbeats
The "lub" sound occurs when __________ valves close.
atrioventricular
The "dub" occurs when ________ valves close.
semilunar
What is a heart murmur?
unusual heart sound; slight whooshing after the "lub"
Is the heartbeat regulated intrinsically?
yes
What does the SA node do?
it itinitiates the heartbeat and sends out an excitation impulse (pacemaker); caused the atria to contract
What is the SA node's location?
it is located in the upper dorsal wall of the right atrium
What is the SA node's nickname?
sinoatrial node
What does the AV node do?
transmits impulses received from the SA node to ventricular walls
What is the AV node's location?
located near the base of the right atrium very near the septum
What are Purkinje fibers?
specialized muscle fibers that conduct the cardiac impulse from the AV bundle into the ventricles
What do Purkinje fibers signal the ventricles to do?
causes ventricles to contract
Is the heartbeat regulated extrinsically? If so, how?
Yes by way of the autonomic system, a portion of the nervous system
Where and what is the cardiac center?
coordinates the activity of the autonomic innervation of the heart
located in the medulla oblongata
The parasympathetic system, which promotes functions associated with normal activities, ___ the heartbeat; while the sympathetic system, which regulates responses associated with stress, __ the heartbeat.
slows, speeds up
What is an ECG?
electrocardiogram: recording of electrical changes that accompany a cardiac cycle
What is indicated by the P wave of an ECG?
atria about to contract
What is indicated by the QRS complex of an ECG?
ventricles about to contract
What is indicated by the T wave of an ECG?
ventricles relax
What are the 2 circuits of the cardiovascular system?
pulmonary and systemic
Know the general route of blood flow through the body.
...
What is a portal system?
a second bed of capillaries; an exception to the usual route
Give an example of a portal system in the human.
hepatic portal system and renal portal system
What is meant by blood pressure?
Pressure of blood against the wall of a blood vessel
What does systolic pressure result from?
blood being forced into the arteries during ventricular systole
What does diastolic pressure result from?
pressure in the arteries during ventricular diastole
Which blood vessel is usually used to record blood pressure?
brachial artery
What is a normal blood pressure reading?
120/80
What is blood?
tissue in which cells are separated by a liquid called plasma
What type of tissue is blood?
vascular connective tissue
What type of tissue is the matrix?
plasma
What are the two main portions of blood?
plasma and blood cells
What are the formed elements of blood?
blood cells or fragments
What is the chemical composition of plasma?
plasma, leukocytes, platelets, erythrocytes
What are the 3 main plasma proteins?
albumin, fibrinogen, and globulin
Where is albumin made and what is its task?
made by liver and takes care of blood volume and pressure
Where is fibrinogen made and what is its task?
made by liver and takes care of blood clotting
Where is globulin made and what is its task?
made by liver and transport and fights infection (antibodies)
What is hemoglobin?
a protein-based component of red blood cells which is primarily responsible for transferring oxygen from the lungs to the rest of the body
What is the significance of iron with regard to hemoglobin?
red blood cell production is decreased most often due to a diet that does not contain iron
How many times does hemoglobin increase the oxygen-carrying capacity of blood?
800-1120 million
Where are erythrocytes made?
bone marrow
Where are erythrocytes destroyed?
red pulp of the spleen
What happens to the erythrocytes hemoglobin?
Hemoglobin is released when rbc are broken down
What happens to the erythrocytes iron?
Iron is recovered and return to marrow for reuse
What happens to the erythrocytes heme?
Heme is degraded and excreted as bile pigments; color of feces and bruises
What may cause anemia?
1. decreased production of red blood cells
2. loss of red blood cells from the body
3. destruction of red blood cells in the body
What may cause hypoxia?
not enough oxygen to some or all of their body
What is erythropoietin?
a hormone
Where erythropoietin it produced?
in the kidneys
What does erythropoietin do?
stimulates the production of red blood cells in the bone marrow when it senses that the oxygen level in the body's tissues is low
What is phagocytosis?
a process which is used by cells to engulf and subsequently ingest particles of nutrients or bacteria.
What are macrophages?
a type of white blood cell which eat foreign material in the body
What do T lymphocytes do?
leave the bone marrow and mature in the thymus
What do B lymphocytes do?
stay within the bone marrow until they are mature. once mature, they spread throughout the body and concentrate in the spleen and lymph nodes
Summarize the steps in clotting using Figure 12.14.
1. platelets & damaged tissue release prothrombin activator
2. thrombin act on fibrinogen to form fibrin threads
3. red blood cells get caught in fibrin threads
What is fibrinogen?
plasma protein that is converted into fibrin threads during clotting
What is prothrombin?
plasma protein converted to thrombin during clotting
What does thrombin do?
converts fibrinogen to fibrin threads
What is fibrin?
insoluble protein threads formed from fibrogen during clotting
What is serum?
light yellow liquid left after clotting
What are stem cells?
any cells that can divide and differentiate into more functionally specific cells
What are 2 types of stem cells derived from multipotent stem cells that give rise to the different type of formed elements?
myeloid stem cells
lymphoid stem cells
What are two forces that primarily control movement of fluid through the capillary wall?
osmotic pressure & blood pressure
Explain briefly what happens at the arterial end of a capillary?
blood pressure is higher than osmotic & water exits
Explain briefly what happens at the mid-section?
forces cancel each other & no water moves
Explain briefly what happens at the venous end?
osmotic pressure is greater than blood pressure; water moves into the capillaries
How does tissue fluid form?
when small substances of of red blood cells and plasma proteins leave the capillaries
Why does tissue fluid usually lack plasma proteins?
because the proteins generally stay in the capillaries
How does lymph form?
when plasma leaks out of blood vessels into the interstitial space
What genetic factors predispose an individual to cardiovascular disease?
1. family history of heart attacks under 55
2. gender
3. ethnicity
Name 3 do's for a heart-healthy lifestyle.
healthy diet, exercise, cholesterol
Name 3 don't for a heart-healthy lifestyle.
smoking, drugs, obesity
What blood type is the universal donor in the ABO system?
O
What blood type is the universal recipient in the ABO system?
AB
What ABO blood types are the most common and the least common among U.S. African Americans?
O-common; B-uncommon
What ABO blood types are the most common and the least common among U.S. Caucasians?
O-common; AB-uncommon
What is agglutination?
clumping of red blood cells
What is an antibody?
a protein found in the blood or body fluid
What is an antigen?
a substance which stimulates an immune response
In the Rh system do Rh+ cells have antigens on their surface?
yes
In the Rh system do Rh- cells have antigens on their surface?
no
Do Rh-negative individuals normally make antibodies against the Rh antigen?
do not normally have antibody for antigen unless exposed to it
When would Rh-negative individuals make antibodies against the Rh antigen?
during pregnancy
Why can this be a problem?
not problem for first baby but subsequent babies if rhogam shot is not administered in pregnancy or no later than 72 hours after giving birth to Rh+ baby
What is HDN?
hemolytic disease of the newborn
What is Blood Type As antigen on the surface of RBC?
A
What is Blood Type As antibody in plasma?
B
Blood Type A can be given to?
A, AB
Blood Type A can receive from?
A, O
What is Blood Type Bs antigen on the surface of RBC?
B
What is Blood Type Bs anitbody in plasma?
A
Blood Type B can be given to?
B, AB
Blood Type B can receive from?
B,O
What is Blood Type ABs antigen on the surface of RBC?
A, B
What is Blood Type ABs anitbody in plasma?
no a, no b
Blood Type AB can be given to?
AB
Blood Type AB can receive from?
A, B, AB, O
What blood type is considered to be the universal recipient and least common?
AB
What is Blood Type Os antigen on the surface of RBC?
no A, no B
What is Blood Type Os anitbody in plasma?
a, b
Blood Type O can be given to?
A, B, AB, O
Blood Type O can receive from?
O
What blood type is considered to be the universal donor and most common?
O
What is the common name for erythrocyte?
red blood cell
What is the common name for leukocyte?
white blood cell
What is the common name for thrombocyte?
platelet
How many erythrocytes are there per mm3?
4-6 million
How many leukocytes are there per mm3?
5,000-11,000
How many thrombocytes are there per mm3?
150,000-300,000
Are erythrocytes nucleated at maturity?
no
Are leukocytes nucleated at maturity?
yes
Are thrombocytes nucleated at maturity?
no
What is the life span in days for an erythrocyte?
120
What is the function of an erythrocyte?
transports oxygen & CO2
What is the function of a leukocyte?
fight infection
What is the function of a thrombocyte?
clotting aid
What is the shape and size of an erythrocyte?
7-8μm in diameter biconcave disks
What is the shape and size of a leukocyte?
10-14μm in diameter spherical
What is the shape and size of a thrombocyte?
2-4μm in diameter disk-shaped
Does an erythrocyte contain hemoglobin?
yes
Does a leukocyte contain hemoglobin?
no
Does a thrombocyte contain hemoglobin?
no
Where are erythrocyte produced?
bone marrow
Where are leukocyte produced?
bone marrow
Where are thrombocyte produced?
bone marrow
Where are neutrophil produced?
bone marrow
Where are eosinophil produced?
bone marrow
Where are basophil produced?
bone marrow
Where are lymphocytes produced?
bone marrow
Where are monocytes produced?
bone marrow
Neutrophil is what % of leukocytes?
40-70%
Eosinophil is what % of leukocytes?
1-4%
Basophil is what % of leukocytes?
0-1%
Lymphocytes are what % of leukocytes?
20-45%
Monocytes are what % of leukocytes?
4-8%
What is the function of neutrophil?
phagocytize pathogens
What is the function of eosinophil?
phagocytize antigen-antibody complexes and allergens
What is the function of basophil?
produce histamine that promotes blood flow to injured tissue
What is the function of lymphocytes?
responsible for specific immunity
What is the function of monocytes?
become macrophages that phagocytize pathogens and cellular debris