The Circulatory System Flashcards
The circulatory system is composed of what?
The heart
What 3 actions does the heart preform through blood vessels?
Transports nutrients, waste products and dissolved gases to and from tissues and organs as well as redistributing heat in the body
Why don’t unicellular organisms need a circulatory system?
They exchange matter directly through their environment through diffusion and active transport
The heart functions as two pumps that drives blood through separate circulatory systems. What are they?
Pulmonary circulation and systematic circulation
What is pulmonary circulation?
Blood pumped from the right side of the heart transports blood back and forth from the lungs to the heart.
What is systemic circulation?
Blood pumped from the left side of the heart transports blood to and from all other organs in the body such as the stomach and the kidneys.
What is blood made up of?
It’s a tissue made up of plasma, red blood cells, white blood cells and platelets
What are arterioles?
branches or arteries with smaller diameter
What are capillaries?
thin (one cell thick) tubes, where the exchange or gasses, nutrients and waste occur
What are venules?
vessles at the end or capillary beds merge to form venules
What are veins formed of and what is their function?
Venules merge to form veins, return blood, towards the neart
What do semi-lunar valves do?
They prevent backflow from arteries into ventricles
What do A-V valves do?
They prevent backrow from ventricle into atrium
What are your heart sounds due to?
your heart sounds are due to the closing of A-V and semi-lunar valves
What is the “LUB” sound in your cardiac cycle due to?
The ventricles contracting forcing the closure of of the A-V valves. It’s louder than the “DUB”.
What is the “DUB” sound in your cardiac cycle due to?
The ventricles contact forcing the closure of the semi-lunar valves. It’s softer than the “LUB”.
What is cardiac output?
It’s the volume of blood the left ventricle pumps into the systemic circuit per minute
What factors affect cardiac output?
Stroke volume and heart rate
What is stroke volume?
Quantity of blood pumped with each beat. ~ (170 mL/b)
What is heart rate?
The number of times the heart beats per minute ~(70 bpm)
How do you calculate cardiac output?
Heart rate x stroke volume
70 bpm x 70mL/1bpm = 4900 mL
What is the S.A. node?
Located in the space where the vena cava enters the right atrium it’s a bundle of nerves and muscle tissue that set the rate of the heart, aka the “pacemaker”. It initiates the nerve impulses to other cardiac muscles cells causing the atria to contract.
What does SA node stand for and what is its function?
sinoatrial node and it’s the “pacemaker”
What does the A.V node stand for?
atrial-ventricular
Where is the AV node located?
between the right atrium + right ventricle (in the wall)
What is the AV nodes function?
• Conductor, passing nerve impulses along specialized tracks (bundle of His and purkinje Fibers) to the ventricles
• ensures atria are completely emply before ventricles contract (apex and upwards) Forcing blood toward the pulmonary artery and aorta.
What are electrocardiograms?
Impulses that travel through cardiac muscle produce electrical currents through body fluids to skin. These impulses are detected as an ECG.
What is blood pressure?
Measure of the force blood exerts on the walls of a blood vessel.
What’s blood pressure measured in?
Millimeters of mercury
mm/Hg
What is systolic pressure?
ventricles are contracted (systole). highest pressure in arteries
What is diostolic pressure?
ventricles are relaxed (diastole). Lowest pressure in arteries
What is blood pressure measured from?
from an artery; the pressure drops substantially by the time blood enters veins
How does blood return to the heart?
with the aid of steletal muscle contraction, squeezing the blood through venules; one way values allow blood flow in one direction
What is blood pressure determined by?
• Cardiac output - greater the cardiac output, the higher the bp
• vasoconstriction and vasodilation of arterioles
What does constriction do?
recluces the diameter of arterioles, increase in BP
What does dilation do?
It increases the diameter of arterioles, decreasing BP
What is vasoconstriction and vasodilation regulated by?
Nerves and hormones
How much blood does the human body contain?
4-6 L
How much of your body mass does blood comprise of? (%)
8-9%
What are the three components of plasma?
90% water
~7% plasma proteins (albumins, globulins, fibringen, prothrombin)
3% Substances that are beings transported from one part of the body to the other (nutrients, dissolved gases, metabolic wastes, hormones, vitamins, heat)
What are red blood cells called?
Erythrocytes
Where are erythrocytes produced?
In the spleen and marrow of long bones
How many RBC are in a micro litre of blood?
5 million
What is the shape of a erythrocyte?
Biconcave disk (thinner in the center than at the edges)
True or false - red blood cells don’t contain nuclei or mitochondria
True
What is a erythrocytes major function?
Carry oxygen
What is hemoglobin (Hb) and how many molecules of it does each RBC contain?
It’s an oxygen carrying protein containing iron and each erythrocyte contains 250 million molecules
What is oxyhemoglobin?
The complex formed when oxygen bonds to four iron molecules and attach to the folded protein structure of hemoglobin
What makes blood red?
Oxyhemoglobin
What is carbaminohemoglobin?
The complex formed when carbon dioxide binds hemoglobin
What is the production of RBC controlled by?
A negative feedback mechanism directed by oxygen levels
What will low oxygen levels stimulate?
RBC production in the bone marrow
If an individual lives at high altitude will they have more or less RBC than and individual who does not? Why?
They will have more to compensate for lower oxygen levels in the atmosphere
How long is the average lifespan of a RBC?
120 days
What is the spleen and livers function?
Remove old RBCs and recycle their parts
What are leukocytes?
White blood cells
What is homeostasis?
Balance within the body
What are the 5 kinds of leucocytes?
Monocytes, neutrophils, basophils, cosinophils, and lymphocytes
Where are leucocytes produced?
Marrow of long bones
Can WBC leave the capillaries and travel in the tissues?
Yes
What is the function of leucocytes?
Fight infections by phagocytosis or the specialization of B cells and T cells which produce the immune response
Where do leucocytes spend most of their time?
Outside the circulatory system in the interstitial fluid and the lymphatic system where encounters with pathogens occur
How big are platelets?
They’re fragments of cells about 2 - 3 µm
Where are platelets produced?
In the bone marrow
What is the lifespan of a platelet?
5-10 days
What is the function of platelets?
Clots blood with the help of proteins found in the blood plasma
Do white blood cells contain nuclei?
Yes
What is the largest blood component?
Leucocytes
What is the liquid component of blood?
Plasma
What is thrombus?
A blot clot that seals a blood vessel
What is embolis?
A clot that has become dislodged and travels through the boy until it becomes lodged in a vessel too small for it to pass
What’s hemophilia?
Blood doesn’t clot due to insufficient blood clotting proteins
What is anemia caused by?
Too few red blood cells or too little hemoglobin inside red blood cells, reduced oxygen carrying ability of blood
May be caused by iron deficiency
What is leukaemia?
Cancer of leucocytes
Myeloid leukaemia- too many leukocytes but immature and unable to fight infection
Lymphoid leukaemia- cancer of the lymphocytes
What is the marker on red blood cells called?
Glycoproteins (antigens)
What is an antigen
An identification protein that can be used to determine if a substance is a foreign invader. If it is then it stimulates the creation of specific proteins called antibodies
What are antibodies?
Proteins produced to combat foreign invaders
What happens when an antibody attaches to an antigen?
Causes the blood to clump (agglutinate)
What are the four blood groups?
A,B,AB, O
What blood group can accept blood from any group? (Universal acceptor)
AB has both A and B antigens and produces no antibodies
What blood group is considered to be the universal donor?
Type O contains no antigens and produces both A and B antibodies
What is the Rhesus factor?
A protein that may be present on a red blood cell.
What percentage of North Americans have the factor on they erythrocytes?
85%
What does it mean if a person is Rh+? -?
Positive means they have the antigen, negative means they do not.
What type of blood can Rh + people receive?
Rh+ or Rh-
What type of blood can Rh- receive?
Only Rh-
What is the first line of defense against infection?
Barriers that prevent the pathogen from entering the body such as tears, sweat, skin, stomach acid, eyelashes, ear wax, cilia lining bronchioles
What is the second line of defense when fighting infection?
One the pathogen has entered the body a general mechanism occurs where increased blood flow at the site of infection causes an inflammatory response
What is the third line of defence?
It’s the immune response. It’s a specific response built up against every invading pathogen
What does a macrophage do?
It’s a type of white blood cell that ingests the foreign invader and presents the foreign antigen on its surface
What do helper T cells do?
Recognize the antigen as a foreign invader and activates the B cells (made in bone marrow)
What do B cells do?
Produce proteins called antibodies and killer T cells which directly kill cancer or infected host cells
What happens once the infection is under control?
Suppressor T cells signals the B cells and killer T cells to stop multiplying
What do memory B cells and memory T cells do?
Remain to remember the invader and to allow for a faster immune response if the body is exposed to the same foreign antigen, this leads to the development of immunity
How long do memory T and B cells last?
4-6 months
How long does it take the immune response if memory B cells and memory T cells haven’t yet been exposed?
5-10 days which gets shortened to 3-5 days once exposed
What is elephantiasis?
Disease caused by a parasite that disrupts the proper functioning or the lymphatic system
