The Circulatory System Flashcards
What are the main functions (3) of the circulatory system?
Transport, homeostasis, and protection
How does the circulatory system maintain homeostasis?
Blood vessels dialate or restrict to dissipate heat or reduce heat loss
What are the types of blood vessels (3)?
Veins, capillaries, and arteries
How long is the total distance of of all vessels?
96000km
What is the function of an artery?
Carries blood (usually nutrient rich) away from the heart
What color are arteries?
Red
What is the difference between an artery and a vein (function)?
An artery carries blood away from the heart while a vein carries blood towards the heart
Why do arteries have to have thick muscular layers?
They must be able to withstand the pressure applied onto them due to the contracting and relaxing of the heart
When measuring blood pressure, what is actually being measured?
The pressure exerted on the arteries by the heart
Tunica Externa of arteries/veins
Outer, protective layer of tough connective tissue
Tunica Media of arteries/veins
Muscle and elastic tissue layers, thick in arteries and thin in veins
Tunica Intima of arteries/veins
Smooth endothelium forming the lining of the lumen
Which part of an artery/vein is actually in contact with blood?
The intima
Why does the lining of the lumen (endothelium) have to be smooth?
It’s where blood flows through
Systolic pressure definition
Maxium pressure applied during ventricular contraction
Synonym for ventricular contraction
heart contracting
Synonym for ventricular relaxation
heart relaxing
Diastolic pressure definition
minimum pressure during ventricular relaxation
How is systolic pressure measured by a sphygmomanometer?
When it first picks up on any pressure
How is diastolic pressure measured by a sphygmomanometer?
When the machine no longer picks up on any pressure
How does a blood pressure cuff work?
By initially cutting off circulation, then detecting when it first picks up pressure and when it loses any sense of pressure
What is the average blood pressure of an adult?
120/80
What unit is blood pressure measured in?
mm/Hg (millimeteres of mercury)
What is the general path that blood flows after it leaves the heart (which order of vessels)?
Heart, aorta, arteries, arterioles, capillaries, venules, veins, vena cava
What is an arteriole
A smaller artery, when an artery starts to branch off
In which blood vessel is the pressure the greatest?
Arota, arteries, arterioles
(Those just leaving the heart)
What is a pulse?
Rhytmic relaxation and contractions of arteries implied upon by the heart
What is the prefix for arteriole?
Vaso
Aneurysm
When the inner wall of an artery bulges outward, putting pressure on the outer wall
What causes aneurysms?
Generally a birth defect, however may be cause due to lifestyle
When do aneurysms become a problem and why?
When it’s broken or erupts, it won’t be able to bring nutrients to desired areas, thereby shutting the organ down
Why do arterioles vasoconstrict or vasodilate?
To control resistance of blood flow
Atherosclerosis
When fat droplets restrict blood flow by reducing the diameter of the lumen
How can atherosclerosis be treated?
Bypass surgery or angioplasty
What is a coronary artery?
Arteries that orginate from the aorata and supply nutrients to heart muscles
Synonym for myocardium
Heart muscle
Coronary occulsion cause
When atheroma binds to the intima of the coronary artery
Atheroma definition
Fatty tissue created by LDL cholestrol
Why is coronary occulsion problematic?
They reduce the diameter of the lumen, reducing the nutrients that reach the heart
What can conronary occulsion cause?
Heart attacks
Symptoms of coronary occulsion (3)
Angina, increased heart rate, blood clotting
Function of veins
Carries blood (usually oxygen depleted) towards the heart
What color are veins
blue
Describe the muscle layers and lumen of a vein
Thin muscle layers, wide central lumen
Can veins contract or dialate?
Veins can dialate but can’t contract
How is blood moved through veins
The skeletal muscles surrounding veins and one way valves
Vericose veins cause
blood buildup between valves due to malfunctioning of a middle valve
Where do men get vericose veins and why
Ankles, subject to most gravity
Where do women get a lot of vericose veins and why
Under the knees, due to crossing legs
Function of capillaries
Responsible for exchange of nutrients between blood and tissues
How thick are capillaries
8 micrometers in diameter, enough for one blood cell to fit through
Structure of capillaries
only intima (endotheleium layer), no muscle
Are capillaries permeable
Yes
Cause of bruise
Capillaries get damaged so blood and plasma gets into interstitial space
William harvey discoveries (3)
Veins have valves, there is only one fluid in the body (blood), heart pumps blood around the body, veins carry blood towards heart, right ventricles supply blood to the lungs, left ventricles supply blood to arteries
Venous system definition
Returns blood to the heart
Arterial system definition
Carries blood to capillaries
Portal systems
Carry blood between two capillary beds
How did William Harvey make his discoveries?
By dissecting dead animals
Which organs are involved in the pulmonary circuit?
heart and lungs
Which organs are involved in the system circuit
The heart and every organ other than the lungs
Where are the lungs located
On either side of the heart
Why must capillaries be so thin?
This encourages slower blood flow, which allows for more efficient diffusion as there is more time for nutrients to diffuse in and out
microcirculation
Flow of blood through capillary bed
Two types of vessels in capillary bed
Vascular shunt and true capillaries
Vascular shunt function
diverts blood past true capillaries when metabolic demands are low
Portal venous system vs regular capillary systems
The blood from a capillary bed drains into another capillary bed instead of going to the heart
Example of a portal venous system
When blood from digestive organs goes to the liver before the heart to detoxify
Where is the heart located?
Center of the chest, slightly to the left
What are the functions of the heart (3)
Acts as a DOUBLE PUMP, keeps oxygen rich and oxygen poor blood seperated, and ensure blood only flows in one direction
Pulmonary circulation
Blood circulates to lungs and back to heart
Systemic circulation
Blood circulates to every other organ in body (except for lungs) and back to heart
Septum
muscular wall that seperates left and right side of the heart
How many chambers does the heart have?
4
Which chambers collect blood from the body?
Left and right atria
Left atrium function
collects blood from the lungs
Right atrium function
collects blood from body
Which 2 chambers are distributers of blood
left and right ventricle
Left ventricle function
Pumps blood to the body
Right ventricle function
pumps blood to the lungs
Vena cava
veins that collect deoxygenated blood
Where does superior vena cava collect blood
Head, chest, and arms
Where does the inferior vena cava collect blood
Central and lower body
Where does the deoxygenated blood of the vena cava pool into?
Right atrium
What is the ONE vein that’s red
pulmonary vein
pulmonary vein function
carries blood from lungs into the left atrium
What is the ONE artery that’s blue
pulmonary artery
pulmonary artery function
carries blood from right ventricle to the lungs
How many pulmonary veins and arteries are there?
2 each
Aorta
Largest blood vessel in the body, leaves the left ventricle carrying oxygenated blood
tricuspid valve
Atrioventricular valve that seperates right atrium from the right ventricle
bicuspid valve
Atrioventricular valve that seperates the left atrium from the left ventricle
What is the strongest valve in the body
Mitral valve (bicuspid valve)
Semilunar valve (2)
Found in the aorata and pulmonary trunk between ventricles and arteries
Why does the heart require its own blood supply
It’s constantly in action, so it has a high metabolic demand
Why should the pulmonary system operate at a lower pressure than the systemic system?
It is responsible for gas/nutrient exchange in the lungs, where the capillaries can’t handle high pressure. Higher pressure also increases osmotic pressure, leading to fluid build up in the aveoli
Why is the thickness of the left ventricle greater than the right?
The right ventricle pumps blood to lungs, which means less resistance and less workload compared to pumping blood to the rest of the body
Where is a heartbeat initiated?
SA node
What is the pacemaker of the heart?
The Sinoatrial (SA node)
What type of muslce is the SA node?
Myogenic muscle
Myogenic muscle definition
Muscle that can initiate action independent of the nervous system
How does the SA node make the heart contract?
When its electrical signal spreads over the two atria
Atrioventricular node function
Recieves electrical signals from the SA node, and transfers it through the bundle of His in the Septum
At what point do electrical signals from the AV node cause ventricles to contract
Once they’ve been transferred to the Purkinje fibers (up the sides of ventricles) after the bundle of His
What exactly creates the sound of the heart
Valves closing
Which valves respectively make the LUB DUB sound
AV valves closing make LUB sound, and semilunar valves closing make the DUB sound
What does an ECG (electrocardiogram) do?
Measure changes in voltage from electrical signal
Which part of the brain ensures SA node keeps the heart beating
Medula oblongata
How does the medula reach the SA node (which nerve)
Vagus nerve
What are some factors that can increase heart rate? (4)
Increased CO2, Decreased O2, Decreased Blood pressure, sympathetic nerve activity
Which hormones stimulate increase in heart rate
Epinepherine (adrenaline)
Which factors decrease heart rate?
Decreased CO2, Increased O2, Increased blood pressure, and parasympathetic nerve activity
Congenital heart defect definition
Heart Defects that were present since birth
Murmur
Congenital, when one or more of the heart valves malfunction (may or may not require treatment)
Hole in the heart
Congenital, a hole in the septum that allows oxygenated and deoxygenated blood to mix
Hypertension
High blood pressure due to fat build up in the lumen
Why is Hypertension regarded as the silent killer
No symptoms present until it is too late
Arteriosclerosis
Any disease where artery walls thicken and lose their elastic properties, limiting blood flow
One type of arteriosclerosis
Atherosclerosis
Myocardial Infarction
Heart Attack, Blood clot in coronary artery
How does an angioplasty work
Balloon is inserted in artery, and opens up restricted areas
How does bypass surgery work
Transplanted blood vessel is used to detour around blockages
How much blood is there in the human body?
5L
What are 3 functions of blood?
Carries oxygen to tissues, removes waste, transports white blood cells (defense)
How much of blood is plasma?
60%
The “fluid” component of blood
Plasma
Function of plasma
Provides coagulation factors (proteins that help with clotting)
What does plasma contain (5)?
water, dissolved proteins, organic molecules, minerals, and dissolved gases
Thrombocytes
Platelets
Where are platelets produced?
In the bone marrow
Appearance of platelets
Irreegularly shaped, colorless, and no nucleus
What is the inactive form of thrombin and how is it activated?
Thrompoplastin and calcium activate prothrombin into its active form, thrombin
What is the inactive form of fibrin and how is it activated?
Thrombin, activated by fibrinogen and calcium
Erythrocytes
Red blood cells
Shape of red blood cells
biconcave
Do red blood cells have a nucleus and why
No, for more effiecient transportation of oxygen
What is the main function of red blood cells
To transport oxygen
What does hemoglobin on cell membranes of RBC help them do
Grab onto oxygen (can grab onto 4 at once)
Size of red blood cells
7.5 microns
Lifespan of microns
120 days
Effect of congenital RBC abnormalities
Leads to mis-shaped RBCs, resulting in less oxygen that can be transported
Effect of lead poisoning on body
Lead binds to hemoglobin, which reduces avaiability of heloglobin to transport oxygen
Effect of Malaria on body
Prevents oxygen from attaching onto red blood cells, which result in less oxygen being transported
Function of spleen
Stores & recycles red blood cells and white blood cells
Hemotocrit
Seperated components of the blood after spinning on centrifuge
leukocytes
white blood cells
Primary function of leukocytes
Protects against infection or malignancy
Types of Pathogens
bacteria, protozoa, viruses, fungi
What are the three classes of leukocytes
lymphocytes, monocytes, granulocytes
How much of WBCs are lymphocytes?
20-40%
Appearance of lymphocyte nucleus
big round nucleus
Two types of lymphocytes
B cells and T cells
What is the difference between b cells and t cells
B cells mature in the bone level and produce antibodies, T cells mature in the thymus and produce other T cells
Functions of antibodies
lock and alter movement of pathogens, promoting their elimination
What activates antibody production in B cells
Interleukins
Where is the thymus
Slightly above the heart
4 types of T cells
Killer T cells, Helper T cells, Supressor T cells, and Memory T cells
Killer T cells function
Directly destroys antigens
Helper T cells function
Stimulates T cells and B cells
Supressor T cells function
Inhibits immune response (inhibits T cells and B cells)
Memory T cells
Remembers the antigens on the pathogen in preparation for future encounters
Macrophage definition
Tissue phagocytes
Monocytes percentage in WBCs
2-8%
Appearance of monocytes
agranular, oval/kidney shaped nucleus, rather transparent cytoplasm
Function of monocytes
Engulfs bacteria and present their antigens on the cell membrane
Granulocytes (3)
Neotrophils, Eosinophils, Basophils
How much WBCs are neutrophils
40-60%
How much of WBCs are eosinophils?
1-4%
How much of WBCs are basophils?
0.5-1%
Appearance of neutrophils
Multilobed nucleus
Function of neutrophils
Engulfs and digests bacteria via phagocytosis
Are neutrophils specific phagocytes
no
appearance of eosinophils
bilobed nuclei, large elongated granules
Lifespan of eosinophils
8-10 days in tissue
Function of eosinophils
Traps parasites, promotes inflammation, controls allergy response
Appearance of basophils
Full of granules, bi/trilobed nucleus(often covered by granules)
What cells do basophils become in tissue?
MAST cells
Function of basophils
Responsible for inflammation and allergies
How do basophils cause inflammation
By releasing histamine, which initiate swelling. This expands blood vessels and allow other white blood cells to enter area
How does an allergic response happen?
When basophils believe that allergins (peanuts, dog hair) are bacteria
Which three white blood cells does cell mediated immunity involve?
Monocytes, T cells, and B cells
Briefly describe how cell mediated immunity works?
Monocytes engulf bacteria and present its antigens to T cellsm which produce other T cells that help kill it. Helpter T cells identify antigens and present it to B cells which produce antibodies to slow down the movement of pathogens
