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Flashcards in Biology 11 Circulatory system Deck (43):

Function of Circulatory/cardiovascular system
-main components

oTransports blood, nutrients, gases and wastes (delivers: nutrients, oxygen, messages/via hormone, toxins; removes: wastes, carbon dioxide, toxins)
Objective is to maintain homeostasis:
• Body temperature regulation (flow of blood)
• Controls blood pressure (speed of blood)

o Pump: heart,
o Blood vessels (veins, arteries, capillaries)
o Fluid/ blood

Functions closely with respiratory (O2 and CO2 exchange) and digestive systems (nutrients)


Types of blood circulation

Pulmonary & Systemic

-Pathway where deoxygenated blood travels to the lungs to become oxygenated and then returns to the heart
-Contains of Pulmonary arteries and veins

-Pathway where oxygenated blood leaves the heart and drops off oxygen to tissues, and then re-enters the heart to become re-oxygenated
-Acts as the transport portion of the circulatory system (delivers nutrients, hormones, oxygen, etc.)
-Distributes heat
-Contains all blood vessels except pulmonary arteries and veins


Blood vessels

arteries → arterioles → capillaries → venules → veins

Arteries: highest Blood Pressure
Capillaries: lowest Blood Pressure
Veins: medium Blood Pressure


Blood Pressure

Blood Pressure: Pressure exerted by blood against a vessel wall
o Systolic pressure (highest pressure, ventricles contract)-->average 100-140 mm Hg
o Diastolic pressure (lowest blood pressure, ventricles relaxed) -->average 70-90 mm Hg
High Blood Pressure: over 140/90

• How:
o Stethoscope: hear sounds of heart
o Squeezing to see blood pressure (using sphygmomanometer)
• Importance: check to see if there is any health/heart problems (high BP→cardiovascular diseases)

• High blood pressure results in hypertension
• Chronic high blood pressure causes heart and kidneys to work harder, increasing risk of heart disease or kidney failure
-HBP also damages arteries-->weak-->burst


Arteries details
-type of blood
-blood pressure level

Function: Carries oxygenated blood away from the heart
*Pulmonary artery only artery that carries deoxygenated blood

-Blood travels at high pressure (therefore must have thick walls to withstand)

-made up of smooth muscle with elastic connective tissue
Three layer walls (thick)→withstand pressure
o Smooth muscle controls diameter (by relaxing and contracting)
o Elastic component so that walls can stretch or constrict

• Divide into arterioles (smaller) which lead to capillaries

Nervous system controls diameter:
vasodilation & vasoconstriction
Dilation: relaxed walls, increase diameter, more flow, lower blood pressure
Constriction: contracted walls, decrease in diameter, less flow, higher blood pressure


Smallest blood vessel in body

-only 1 cell thick
-Very tiny, close to organs and tissues (for transfer or nutrients, oxygen, etc.)
-Carries both oxygenated and deoxygenated blood
o Due to gas delivering oxygen, which leaves blood deoxygenated
-When merging away from the arteries they exchange for CO2
-Connection between veins and arteries

-Form network of blood vessels that supply oxygen and nutrients to every cell
-massive surface area
-Thin walls →Gases exchange can occur via diffusion


Vein details
-type of blood
-blood pressure level

Function: Carry deoxygenated blood back to the heart
*pulmonary veins carry oxygenated blood back to heart

-Carry blood at much lower pressure

-Valves: to prevent backflow of large volume of blood, maintain a constant direction of blood flow
- Muscles help with this: Chordae tendineae
-Wider in diameter, but lower pressure and thinner walls than arteries
-Divide into venules (smaller)

-These structures allow the blood to flow faster to rid the body of wastes (CO2)


Components of blood

Blood is a fluid connective tissue that carries oxygen, nutrients, and other solutes to cells, and carries away their metabolic wastes and secretions (hormones).
• Viscous fluid (thicker than water)
• Helps regulate body temperatures, fight infections, heal wounds

Made up of plasma, blood cells, and platelets

-50-60% of blood (top layer when separated)
-Protein-rich Fluid portion of blood that carries wastes, gases, and nutrients
-These proteins have many roles, such as in blood clotting or immunity (Ex : fibrinogen is converted into fibrin when forming blood clots)
-Absorbed nutrients and gases travel in the plasma

Blood cells and platelets: (bottom-from stem cells in red bone marrow)
-Red and white blood cells
-platelets (with clotting factors, harden blood)

A sample of blood can be spun in a centrifuge
 high speed, circular motion
 causes blood to separate by the densities of its components



Red Blood Cells
• Very abundant (body needs oxygen)
• Produced in bone marrow, stored in spleen
• Constantly destroyed and replaced
• Distinct biconcave shape
oFlattened disc that is pinched in the centre
oMakes it flexible for traveling through various blood vessels
Ex: slip easily through narrow blood vessels and faciliatates gas exchange
• No nucleus
• No mitochondria
• Contain hemoglobin →transports oxygen from lungs to tissues

Mature red blood cell contains glucose and enzymes to last about 120 days


What is Hemoglobin?

Hemoglobin: Pigment that allow cells to carry oxygen.
-Complex PROTEIN made up of 4 protein chains, each with a central IRON-containing HEME group. Oxygen binds to heme on the hemoglobin molecule

-Iron gives RBCs their distinct red colour
-Iron binds with oxygen
-(4 O2 molecules per hemoglobin molecule) – blood becomes oxygenated
-Iron is recycled in bone marrow
*Lack of iron results in little hemoglobin, therefore does not carry a lot of oxygen (because not able to bind with oxygen)



White blood cells

-Larger than red blood cells, but fewer in number (normally)
o Body does not need too many white blood cells (not always have infection)
-Contain nucleus and lysosomes (RBC no nucleus)
-Lysosomes digest foreign bacteria

-For defense (fights off infections and foreign substances that body needs to get rid (Part of body’s immune response system)
-Not abundant (because body does not need to fight infections all the time)
-Produced in the bone marrow
-Detects and defends body from infection and diseases by attacking foreign substance
-An increase in white blood cells indicate the body is fighting an infection
-Pus is formed at site of infection

o Consists of: White blood cells (living & dead) + bacteria
o Body’s natural “soap” →to get rid of bacteria



What?: Cell fragments from the bone marrow that have a role in clotting
-After a platelet forms and activated, it releases substances needed for blood clotting
-Important for circulatory system repair

Function: form blood clots
1) Platelets detect damaged blood vessels (opening)
2) When a platelet is activated (after detecting damage), it releases substances needed for blood clotting
• burst and release special adhesive chemicals, causing the platelets to stick together and form a platelet plug (stops wound from bleeding)
3) Through chemical reactions and clot formation, forms strand-like fibrin molecule. A mesh of fibrin strands forms a blood clot (traps cells and platelets)


Blood Clot formation

Hemostasis: Process by which blood clots are formed in response to injury
• Blood clots stop blood loss and constructs framework for repairs (by body)
3 phases:
1. Smooth muscle in damaged vessel wall contracts in an automatic spasm
2. Platelets (found in blood) stick together at the injured site. They release substances that prolong the spasm and attract more platelets.
3. Plasma proteins convert blood to a gel and form a clot. During clot formation, fibrinogen (soluble plasma protein) is converted (by enzyme thrombin) into insoluble threads of fibrin, which forms a mesh that traps cells and platelets.


Importance of blood clots + Problems with blood clots

• Clot protects body from losing blood through the damaged vessel
• Holds vessel wound together until it can be reconstructed with new tissue growth

Problems occur when blood clots can occur when not necessary:
• I.e: elevated leg makes body think that there is an excess of blood in lower limbs, therefore develop blood clot
• Blood clot may break away and clot in clot in a vessel that supplies blood to a critical spot (lungs, heart, brain)


Blood Types

• Four blood types (A, B, AB, O) -->+ and –
• Each letter refers to a kind of antigen, or protein, on the surface of red blood cells.
-+ and - based on rhesus factor

Antigens: any substance that causes your immune system to produce antibodies against it


Blood Typing

Blood typing: Analysis of specific surface molecules on red blood cells
• Can prevent mixing of blood from incompatible donors and recipients
• ABO blood typing
o Identifying certain glycoproteins (A or B) on red blood cells
• Rh blood typing:
o If Rh (type of protein) is present on an individual’s red blood cells
• Present → Rh +
• Absent → Rh –
• Both involve the presence of protein on the red blood cells
* If body receives unknown blood, it will react against the blood cells


Special qualities of certain blood types

Type O
o “Universal Donor”: Can be transfused into anyone
•No markers: molecules in blood that signal what they are and signal immune)
o Can only accept type O

Type AB
o Universal Recipient: Can accept from anyone (A, B, O is always donor)
• Because has both markers
o Can only be transfused to AB


Rhesus Factor (Rh)

• An antigen that produces an antibody reaction
• Refers to a specific protein found on the surface of red blood cells.

Rh positive (most common): Blood has the protein
-Present in approximately 85% of the population

Rh negative: Blood lacks the protein
15% of the population are Rh negative
• Donate blood to Rh positive
• Cannot receive from Rh positive

Importance: Affects compatibility of blood (for donations)



Function: to pump blood
How? (structure):
-Double pump/ventricle: Right side vs left side
-Consists of right & left atrium, right & left ventricle
-Left side bigger: ventricle has to pump oxygenated blood to the rest of the body, therefore requires more muscle
-Heart is a muscle (cardiac muscle) (therefore exercise strengthens heart)
-Heart is covered and protected by pericardium (connective tissue)
-Consists of cardiac muscle, lining is epithelium
-Septum divides heart to prevent mixture of deoxygenated and oxygenated blood (Decrease likelihood of pumping deoxygenated blood to tissues and organs →lead to function problems)
-High fluid pressure forces valves open (decline in pressure →closed valves)

-Heart beat controlled by natural pacemaker in the heart wall
-Cardiac Arrest: when the pacemaker malfunctions, resulting in abnormal heart beat

• Ventricles contract (need more muscle than atria)
• Atria fill up blood in ventricles
• Lub-dup sound
o Lub: AV valves closing
o Dup: aortic and pulmonary valves closing


Cardiac Cycle

Cardiac Cycle: sequence of contraction and relaxation of heart chambers that occurs with each heartbeat
• About 0.8s

Two phases:
o Diastole: relaxation; heart fills up with blood
o Systole: contraction; heart empties blood

Diastole: Heart is relaxed →both atria expand with blood→when atria is full, blood pressure forces AV valves to open, allowing blood to flow into the relaxed ventricle
•Atria then contract to push remaining blood into ventricles (full ventricle)
•Once ventricle full, AV valves close (lub) when ventricles begin to contract
•Systole: Ventricles fully contract, which raises fluid pressure inside the ventricles and forces the aortic and pulmonary valves to open. Blood flows through these valves and out of the ventricles.
•Emptied, the ventricles relax while the atria fill up again.



Sinoatrial (SA) Node: a clump of specialized cells located in the wall of the right atrium that generates an electrical signal

•Cardiac “pacemaker” →initiates heart beat
•Rhythmic signals from SA node make cardiac muscle cells of the heart wall CONTRACT in a coordinated fashion
•50-100 electrical signals per minute (SA nodes carry electrical signals)
•SA node generates an electrical impulse that initiates the contraction of the heart the atrium by causing atria contract

Atrioventricular (AV) node: clump of cells that serves as the electrical bridge between the atria and ventricles (located between the right atrium and right ventricle)

Both SA and AV nodes release bursts of electrical energy, which travel through the heart muscle, causing it to contract.
o SA node sets the rhythm of your pulse, AV node sets the rhythm of your heart contractions


ECG and waves of the heart beat

•Measures the electrical signals & activity of the heart (electrical activity controls heart beat) by reading signals for SA and AV nodes

•How? Connected to the body using a number electrodes (12)

• Importance: can provide evidence for the presence of abnormal heart conditions (by comparing ECG patterns)
Waves: P, Q, R, S, T

•Heart rests/relaxes (no electrical activity) before SA node is activated

-P wave: SA node generates an electrical impulse that spreads over the right and left atira (not ventricle due to non-conducting band which blocks spreading). Atria excitation begins, causing atria to contract

•Q wave: AV node receives the signal from the SA node, then after a short delay at the AV node, the AV node sends an electrical impulse that travels down the septum and splits into left and right branches (carry the electrical signal to the walls of the ventricles). Ventricles fill; delay

•R wave: electrical impulse travels over the ventricles (ventricular excitation cause contraction of ventricle). Bicuspid and tricuspid valves close (Lub) →blood is pushed through open semilunar valves

•S wave: ventricle excitation complete

•No electrical activity for a brief period of time when impulse has travelled throughout the heart (heart is relaxed).
-Then, the heart begins to 'recharge' from the inside to the outside. This causes a bump in the ECG, called the T wave. Ventricular relaxation; Semilunar valves close

•Heart beat very quickly; takes about 0.3 seconds for an electrical impulse to travel from the SA node to all the parts of the ventricles!


Disorder: Atherosclerosis

Cardiovascular disease characterized by plaque build up due to excessive fat in blood vessels (particularly arterial wall)

•Plaque: accumulation of cholesterol and lipids
•Atherosclerosis constricts blood flow through arteries by narrowing the pathway for blood to flow through

• Pop artery
• Formation of blood clot (in addition to plaque)→fully block passage
• Reduce transportation of oxygen and nutrients to tissues (leads to loss of function and Heart attack, stroke)

*Coronary arteries often, thus causing coronary artery disease

Treatment: remove plaque via surgery (recovery process involves eating less fatty foods)

•Too much fat -->build into plaque--> build onto walls of arteries


Disorder: Angina

•Tightness in chest due to coronary artery disease (narrowing of coronary arteries that supply blood to heart)
-Symptom of early stages in heart attack

oCause: plaque build up→ blood clots →blocking coronary arteries→less blood flow
oNot supplying enough oxygen to parts of the heart, which leads to deprivation of oxygen that creates muscle pain and strain
oSevere blockage can lead to heart attack
•Pain can also be felt from physical exertion, eating too quickly, stress

Relief from pain:
o Ex: nitroglycerine: pill (type of vasodilators)/spray
Dilates blood vessel and reduces resistance by relaxing blood vessel. This allows for easier blood flow and oxygen to be delivered to deprived areas of the heart.

Nitroglycerine is absorbed by blood vessels without difficulty and mimics negative feedback response to oxygen deprivation to restore homeostasis.


Disorder: Anemia

Medical condition when there is a less than normal amount of healthy red blood cells or hemoglobin in the blood

•Less hemoglobin, less O2 being delivered throughout the body (O2 do not bind to RBC)

-Great Blood loss from a wound or infection
-Diet with too little iron (preventing the synthesis of iron-containing heme)
-A genetic disorder (e.g., sickle cell anemia or thalassemias)

Sickle Cell Anemia
o Blood cells have a sickle/moon shape
o Prevents cell to bind to oxygen easily
o Hemoglobin changes shape at a low oxygen concentration

Thalassemia is a genetic disorder which passes down abnormal form of hemoglobin.

• Anemic people have trouble blood clotting


Disorder: Leukemia

Cancer of white blood cells

oResults in too many white blood cells being produced in the bone marrow (these wbc do not function properly)
oNot enough red blood cells -->not enough oxygen due to bone marrow too crowded
oNot enough platelets to ensure proper clotting
oNot enough normal WBC to fight infection
Bone marrow is unable to manufacture other blood cells

Malignant white blood cells can leave bone marrow, travel blood stream and affect other organs

•Chemotherapy (target white blood cells and killing the cancer white blood cells)


Disorder: Hemophilia

Blood does not clot normally as the body lacks special proteins that are needed for creating blood clots

o Can bruise easily → the small blood vessels (capillaries) beneath the skin break easily and frequently. They then leak blood into the surrounding tissue and create discolorations.
o Can bleed excessively if cut – sometimes bleeding to death →no blood clots

Hemophilia is a X-linked genetic disorder (inherited)


Disorder: Shock

Life-threatening medical condition due to insufficient blood flow throughout the body, resulting in not enough O2 delivered

•Occurs when the body (or parts of body) shuts down because circulatory system cannot meet oxygen demands of some vital organs

Cause: loss of blood, extreme fright or emotional disturbance ( Psychological causes: Body thinks that human is in danger, therefore will send hormones to body to deliver blood to the core, thus resulting in less blood flow to other parts of the body)

•During shock: Body reduces blood flow to arms and legs so it can maximize O2 getting to the vital organs (in body’s core→ heart and brain)

Since shock is life-threatening, must perform immediate First-Aid:
• Put person in half upright position →blood flow
• Keep warm→allows for more blood flow
• Apply direct pressure to any areas of severe bleeding →to stop bleeding
• Get (call for) medical help


Disorder: Hypertension

•Chronic High Blood Pressure (prolonged pressure above 140/90)
oHigh BP makes Heart work harder than normal →heart becomes enlarged and it functions less efficiently

o Environmental: inactivity, stress, obesity, salt, trigger factors etc.
o Hereditary

•Result: can cause coronary heart disease (plaque build up on walls of coronary artery and can reduce or even block blood flow)

Treatment: Hypertension Relief
oGoal: to lower arteriole blood pressure and decrease cardiac output (Decrease the amount of blood body needs)
• Improved nutrition
• Physical Activity
• Medication: Ex-
Vasodilators: medications that widen (dilate) blood vessels (increase blood flow, decrease blood pressure and resistance in the blood)

Diuretics (water pills): helps body get rid of unneeded water by increasing urination. This reduces body fluid, which leads to less fluid to create pressure and thus lower blood pressure. →easier for heart to pump

o Lower BP can help body maintain homeostasis


Disorder: Heart Attack

Severe form of angina

Occurs when cardiac muscle cells in the heart die due to a blockage (clot) in the coronary arteries (supply blood to heart).

•Result: heart is unable to pump and function as efficiently
o Fatigue
o Dizziness or light-headedness
o Indigestion

Risk Factors:
o Controlled: smoking, poor diet/nutrition, obesity, lack of exercise, stress, diabetes (type 2)
o Other: Age, Family history of heart disease

Person may have more than one heart attack due to the scars on tissue (damaged) that can interfere with coronary circulation and potentially prevent other areas of the heart from receiving enough oxygen →another heart attack


Disorder: Stroke

Occurs when brain cells in the brain die due to a blockage to the arteries that supply oxygen and blood to brain.

• Hemorrhagic (burst of blood vessel due to high blood pressure→internal bleeding)
• Ischemic (blood clot in blood vessel→brain tissue dies due to lack of oxygen)
o Result: loss in brain function and dead brain tissue

Symptoms: Some can be reversed
o Varies
o Symptoms typically shown on opposite side of affected brain
o All "sudden": weakness or numbness, severe headache, dizziness or loss of balance, vision problems, Slurred speech or comprehension difficulty, confusion


Affects of smoking

Cigarettes contain nicotine: an addictive substance in tobacco that increases blood pressure and heart rate.
-nicotine makes blood vessels sticky, which cause substances (i.e. saturated fats) to stick to the walls
• Result: are risk factors for serious health problems (heart disease, lung cancer)
• Similar: cigarettes (tar and carbon monoxide)


Disorder diagnosis

Exercise Stress Test:
oTo determine the amount of stress that your heart can manage before developing either an abnormal rhythm or evidence of ischemia (not enough blood flow to the heart muscle)
• Individuals walk on a treadmill (to increase heart rate, speed and incline)
• Individual is monitored using ECG readings, blood pressure, and physical symptoms (e.g., if individual has shortness of breath or angina)

Nuclear Medicine:
• Radioactive thallium201 is injected during a stress test and pattern of radioactive decay in coronary arteries is examined (radioactive appears clearly on x rays)

Cardiac Catheterization:
• Using a catheter (injected in femoral artery) to guide itsway to the coronary artery. Dye is then injected and fills coronary arteries (allows for more vision of artery walls). Angiogram (special X-ray) is taken of blood vessels that can reveal location of blockages.


Surgery for disorders

for clogs in coronary arteries

Angioplasty: small balloon is inserted through cardiac catheter. The balloon is inflated to help dilate the coronary arteries. Ex: atherosclerosis (tightening of walls)

Bypass Surgery: A portion of the blood vessel (vein) is removed and inserted (via surgery) in the heart (typically a leg vein). The vein then acts as an alternate pathway (creating a shunt). This allows circulation to bypass an arterial blockage in the coronary arteries and restore blood flow to heart muscle.


Exercise benefits

• Reduces risk of developing heart disease.
• Strengthens heart, lungs, and bones.
• Muscles become toned giving more shape to the body.
• Exercise allows body to utilize sugar and maintain blood sugar levels (can reverse type 2 diabetes) →Diabetes can be controlled,
• Other: improved concentration and memory, and a reduction in stress levels.


Exercise effects

• Causes muscles to increase cellular respiration →produces more oxygen and lactic acid
o Acids results in acidic pH of blood and causes blood vessels to dilate while stimulating deeper and more breathing to replenish O2 in the blood.
• Heart rate increases, so oxygenated blood is pumped more efficiently throughout body.
• Regular exercise increases body’s capacity to utilize oxygen (e.g., 10% more in athletes).
• Muscle memory -->muscle is used to increasing heart rate if exercise often (therefore do not have to work as hard)


Blood type receive and donate info

A+: only receive from A+, A-, O+, O-; can donate to A+, AB+
A-: only receive from A-, O-; can donate to A-, A+, AB+, AB-
B+: only receive from B+, B-, O+, O-; can donate to B+, AB+
B-: only receive from B-, O-; can donate to B-, B+, AB+, AB-
O+: only receive from O+, O-; can donate toO+, A+, AB+, B+
O-: only receive from O-; can donate to all blood types

- can receive from only -


What increases blood pressure?

-lots of salt, which leads to fluid retention and more blood volume

Plaque does not cause high blood pressure. It simply reduced blood flow, making blood harder to circulate. this can cause blood clots


How does high blood pressure cause blockages in blood vessels?

High blood pressure causes scarred arteries (damage to walls), which that fill up with plaque and become more prone to blood clots


Complete Blood Count

Complete blood count: a blood panel that gives information about the cells in a patient’s blood. The complete blood count measures the concentration of cellular components of blood (RBC, WBC, platelets).
• # of RBC, WBC
• Plasma Composition
• Hemoglobin (iron) levels
• 02 levels
• Sugar levels
Information is used to determine a body’s medical conditions/heath by comparing the concentrations to normal/regular concentrations

Proportion of each component and the number of each type of cell in a specific volume of blood should fall within an acceptable range
• If not: indicate a health problem


Heart Rhythm: comparing myogenic muscle to nervous system

Heart Rhythm:
• Heart can relax and contract on its own
o How? Heart can generate its own electrical signal by creating electrical impulses that travel to different nodes in the heart
• Cardiac muscle is described as Myogenic muscle: muscle can contract and relax without input from external nerve stimuli (rate of contraction and relaxation can be adjusted by the nervous system) →Safety mechanism to ensure heart will continue to beat if nervous system is damaged
• Heart beat is initiated at a cluster of cells
o Sinoatrial (SA) node
o Atrioventricular (AV) node
• Both SA and AV nodes release bursts of electrical energy, which travel through the heart muscle, causing it to contract.
o SA node sets the rhythm of your pulse, AV node sets the rhythm of your heart contractions


How can vasoconstriction allow for the body to efficiently use the amount of blood available?

More blood volume in the vessel, which leads to more blood available to reach vital organs

-heating mechanism


Blood doping

Blood Doping: re-injecting blood cells into athletes before a competition. This increases the RBC and O2 in the blood, which allows muscles to work more efficiently. Also, athlete’s usually train with less erythrocytes to build oxygen tolerance.