Circulatory and Respiratory Systems Test - Yr 11 ATAR

Chapter 4 and 5 for Human Biology

Why do humans have a double circulatory system

. right side of heart pumps deoxygenated blood to lungs for oxygenation = pulmonary circulation

. left side of heart pumps oxygenated blood to rest of body (is thicker) = systemic circulation

Describe the hearts chambers

. heart has 4 chambers

. 2 thin walled atria on top: receive blood

. 2 thick walled ventricles underneath: pump blood

—> veins carry blood into atria + arteries carry blood away from ventricles

Describe the locations of valves in the heart

. between the atria + ventricles are atrio-ventricular valves: prevent back flow of blood from ventricles to atria

1. Left AV valve has 2 flaps = bicuspid/mitral valve

2. Right AV valve has 3 flaps = tricuspid valve

Also are 2 semi-lunar valves in arteries

3. Pulmonary valve

4. Aortic valve

What are the left and right halves of heart separated by?

. the septum

Which ventricle has thinner walls and why?

. walls of right ventricle are 3x thinner than left

—> it produces less force and pressure in the blood as the blood has less distance to travel (lungs only)

Draw the process of gaseous exchange

. the absorption of oxygen from the air in exchange for CO2 removed from the body, taking place in alveoli of lungs

Process:

1. Gases move from an area of high pressure to an area of low pressure in diffusion

2. Oxygen is inhaled and taken to alveoli

3. Oxygen moves from alveoli into the capillaries + blood

4. CO2 moves from capillaries in blood into alveoli + exhaled

5. Blood is now oxygenated + will be transported to rest of the body

What happens when the heart’s cardiac muscle contracts?

. the volume in the chamber decreases, so the pressure in chamber increases, forcing blood out

What type of muscle is the heart?

. cardiac muscle

—> myogenic (contracts on its own without needing nerve impulses)

—> made of myocytes

Stage 1 of Cardiac Cycle: Atrial Systole

Stage 2 of Cardiac Cycle: Ventricular Systole

Stage 3 of Cardiac Cycle: Diastole

What is the lub dub sound of the heart caused by?

lub: the atrioventricular valves closing during ventricular contraction

dub: the semilunar valves closing as the ventricles relax. 

Explain how the heart is a double pump

1st: blood is pumped to lungs + returns to heart (via right side)

2nd: blood is pumped to respiring muscles + back to heart (via left side)

—> 1. Deoxygenated blood is pumped from heart to lungs (right side)

—> 2. Blood receives oxygen + pumped back to heart

—> 3. Oxygenated blood then pumped to rest of body (left side)

—> 4. Oxygen leaves blood to be used for respiration in body + blood goes back to heart

Cardiac output

. the amount of blood flowing in a given time

Heart rate x stroke volume = cardiac output

What are the benefits of increased cardiac output during exercise (5) ?

1. oxygen to muscles faster

2. glucose to muscles faster

3. CO2 away from muscles faster

4. Lactate away from muscles faster

5. Heat away from muscles faster

Difference between systemic and pulmonary arteries and veins?

Systemic arteries: carry oxygenated blood to rest of body

Systemic veins: carry deoxygenated blood to heart from body

Pulmonary arteries: carry deoxygenated blood to lungs

Pulmonary veins: carry oxygenated blood to heart from lungs

Veins and venules description

function: to carry blood from tissues to heart

—> thin walls since blood at low pressure

—> large lumen to reduce resistance to flow

—> many valves to prevent backflow

—> blood at low pressure: BP naturally decreases as moves from arteries (close to heart) towards veins (further), due to the resistance blood encounters as it flows through the blood vessels

—> blood usually deoxygenated (except pulmonary vein)

Arteries and Arterioles description

function: to carry blood from heart to tissues

—> thick walls with smooth elastic layers to resist high pressure + muscle layer to aid pumping

—> small lumen

—> no valves (except in heart)

—> blood at high pressure: directly connected to heart + force of heart’s pumping action creates high pressure helping blood reach all parts of body

—> blood usually oxygenated (except in pulmonary artery)

Capillaries description

function: to allow exchange of materials between blood + tissues

—> very thin (1 cell thick), permeable walls to allow exchange of materials

—> very small lumen (blood cells distort to pass)

—> no valves

—> BP falls: due to large total cross-sectional area, increased resistance to blood flow caused by small diameter, low velocity of blood flow allowing for efficient exchange of nutrients + waste products

—> blood changes from oxygenated to deoxygenated (except in lungs)

How are ABO blood groups distinguished

. the difference is due to the presence of antigens on the plasma membranes of RBCs + the presence or absence of antibodies in plasma

What happens if someone receives incompatible blood?

. donor antigens react with antibodies in patient’s plasma and an immune response called agglutination can occur

What is agglutination?

. clumping together of RBCs due to the interaction between antigens + antibodies

What is the ABO blood group system?

. a method of classifying blood types according to the antigens on the surface of the RBCs

—> 4 types: A,B,AB,O

—> 2 sugar antigens involved: antigen A and antigen B

How is your ABO blood group determined?

. by your DNA and is thus inherited

. on surface of the RBCs a person may have either antigen A, antigen B, both antigens (AB) or neither antigen (O)

ABO blood compatibilities

Blood group typing table

The Rhesus factor transfusions table

Lymphatic system’s role in defence

. larger particles (bacteria) are trapped in the meshwork of fibres

—> large phagocytic cells (macrophages) destroy these particles in phagocytosis

. when infection occurs, formation of lymphocytes increases, causing the lymph nodes to become swollen + sore (part of immune response)

3 Functions of lymphatic system

1. collects + returns excess tissue fluid that has escaped the blood in circulatory system, back to circulation

2. filter lymph fluid containing pathogens + cell debris and destroy it

3. Activate the immune system

Difference between lymphatic system and circulatory system

. lymphatic has no RBCs, does not circulate and has no pump

Breathing (ventilation)

. the process of moving air into and out of the lungs

. purpose is to exchange oxygen + carbon dioxide between lungs and air

Respiration

. the transport of oxygen from the air to the tissues and the transport of CO2 in the opposite direction

External respiration

. the movement of O2 and CO2 between the lungs and bloodstream

Internal Respiration

. the exchange of O2 and CO2 between blood and tissues

How is oxygen transported

. oxygen combines with haemoglobin in RBCs to form oxyhaemoglobin

How is carbon dioxide transported

. most CO2 is transported in the plasma as dissolved bicarbonate ions

The Process of Inspiration

1. External intercostal muscles contract, pulling ribs up and out

2. Diaphragm contracts + flattens downwards

3. volume of thorax increased

4. Volume of lungs + alveoli increased

5. Decreases pressure of air in alveoli (below atmospheric)

6. Air flows in to lungs to equalise pressure

The process of normal expiration

1. External intercostal muscles relax, allowing ribs to fall

2. Diaphragm relaxes + curves upwards (elasticity returns)

3. Volume of thorax decreased

4. Volume of lungs + alveoli decreased

5. Increases pressure of air in alveoli (above atmospheric)

6. Air flows out of lungs to equalise pressure

Describe forced expiration

1. Internal intercostal muscles contract, pulling ribs downward

2. the abdominal muscles contract, pushing diaphragm upwards

—> gives a larger + faster expiration, used in exercise

Describe what asthma is

. medical condition that causes difficulty breathing due to a narrowing of the airways

What does asthma occur due to

. smooth muscles contracting, narrowing the airway

. inflammation causing the lining of the airways to thicken, narrowing its diameter

. mucus filling the airway, narrowing the tube

Triggers of asthma

1. allergic response to allergen

2. a non-allergic response

. air pollutants, exercise, cold air, infection, anxiety, stress, smoke, some medication

Asthma effect on respiratory system

. much greater resistance to air flow in and out of alveoli, making it difficult to ventilate lungs

—> hard to maintain a diffusion gradient as a result of reduced flow

Symptoms of asthma

1. difficulty in breathing: due to constriction + inflammation

2. wheezing sounds: due to air passing through very constricted passages

3. Tight feeling in chest: a consequence of not being able to ventilate the lungs because of constriction in bronchi + bronchioles

4. Coughing: a reflex action to obstructed bronchi + bronchioles

How does the structure of alveoli aid in gas exchange?

1. 1 cell thick epithelial cells + capillaries

2. Blood capillaries throughout/around them = rich supply of blood + high rate of diffusion

3. High SA:V ratio

Blood vessels in the heart

1. Aorta

2. vena cava

3. Pulmonary artery

4. Pulmonary vein

Describe the rhesus blood group system

. based on antigens that occur on surface of RBCs

. Rh antigens are proteins

. With Rh antigens = Rh+, without = Rh-

—> without is able to produce an anti-Rh antibody that reacts against those antigens

—> Rh+ cannot produce an anti-Rh antibody

Blood transfusion

. the transfer of blood, or one of the components of blood, from one person to another

—> avoid bringing together corresponding antigen and antibody since agglutination will occur

—> however in reality, incompatible antibodies in transfusion are diluted by recipient’s plasma, so this can be safe

When is a blood transfusion given and what does this involve?

. given to a person suffering from: excessive blood loss, anaemia, leukaemia, haemophilia

. involves: blood or a blood product, from a donor being injected directly into patient’s bloodstream

Different types of blood transfusions (6)

1. Whole blood: blood as it is taken from the donor but with a chemical added to prevent clotting.

2. Red cell concentrates: produced by spinning blood at very high speed in a centrifuge. The heavier cells sink to the bottom, leaving the lighter plasma on top. The concentrate may or may not have platelets and white blood cells (leucocytes) removed. Transfusions of red cell concentrates are used for patients suffering from heart disease or severe anaemia

3. Platelet concentrates: given to patients who have abnormal platelets or a reduced number of platelets

4. Cryoprecipitate: obtained by freezing the plasma and thawing it slowly. When the plasma is thawed, the cryoprecipitate remains solid. It contains many of the substances necessary for blood clotting. Cryoprecipitate may be used to treat some forms of haemophilia, but it is most often used for severe bleeding.

5. Immunoglobulins: group of proteins that act as antibodies. They are extracted from the blood and used for patients who are deficient in antibodies. e.g tetanus immunoglobulin may be used to treat tetanus.

6. Autologous transfusion: when the patient’s own blood is used. The blood is collected from the patient prior to an operation that may require a transfusion. Autologous transfusions eliminate the risk of transmission of disease and most possible side effects of the usual transfusions.

How does blood group typing work

. before any transfusion, patient’s blood group needs to be determined

—> done by: adding pure anti-a and anti-b antibodies to small spots of patient’s blood

How is lymph fluid formed

1. fluid leaks out of the arterial end of a capillary due to high pressure

2. Some of this fluid returns to capillary at venous end but excess fluid surrounding tissues is returned to blood via lymphatic system

What’s the lymphatic system and lymph

. a one-way drainage system that carries lymph from body tissues back to general circulation

Lymph = a clear yellow liquid that carries WBCs (especially lymphocytes)

What is the blood

. a liquid connective tissue

Functions of blood (3)

1. Transport: nutrients, O2, water, hormones, heat TO tissues + removes waste: CO2, urea, creatinine, uric acid

2. Regulation: pH levels + body temp

3. Protection: prevents blood loss if blood vessels are damaged + protects body against pathogens + toxins

Blood volume components

1. Plasma: liquid

2. Cells: formed elements - RBCs (erythrocytes), WBCs (leukocytes), platelets (thrombocytes)