Respiratory and Circulatory Systems

Question 1

Define the Respiratory System

Answer 1

A system that transports oxygen into the body and transports carbon dioxide out of the body.

Question 2

Define external respiration and internal respiration

Answer 2

External respiration is the movement O2 + CO2 between the lungs and the bloodstream.
Internal respiration is the exchange of O2 + CO2 between the blood and the tissues

Question 3

What is ventilation?

Answer 3

Ventilation is the process of moving air into and out of the lungs. The purpose of breathing is to exchange oxygen and carbon dioxide between the lungs and the air. Air flows from an area of high pressure to an area of low pressure. Air flows in and out of lungs due to differences in air pressure.

Question 4

Define inspiration.

Answer 4

Inspiration is also known as inhalation, the process of taking oxygen into the body. During inspiration, the pressure within the lungs must be less than that of the outside environment, which is done by increasing volume.

Question 5

Describe the movements of the respiratory organs during inspiration.

Answer 5

1. Intercostal muscles contract, extending ribcage upwards and outwards. Diaphragm contracts, extending chest cavity downwards.
2. Lung volume increases.
3. Air flows form higher pressure to lower pressure in lungs.

Question 6

Define expiration.

Answer 6

Expiration is also known as exhalation. During expiration, the pressure within the lungs is greater than that of outside the body, by decreasing volume in lungs.

Question 7

Describe the movements of the respiratory organs during expiration

Answer 7

1. Diaphragm relaxes, pushing up into chest cavity. Ribcage moves down and inwards
2. Lung volume decreases.
3. Air flows from higher pressure in lungs to lower pressure outside.

Question 8

Why are lungs well suited to their function?

Answer 8

The alveoli give the lungs a huge internal surface area, so that large amounts of gases can be exchanged quickly. Each alveolus is well supplied with blood vessels; the continuous flow of blood helps to maintain a difference in concentrations of oxygen and carbon dioxide in the blood and in the air in the lungs. The membrane of the wall of the alveolus is very thin, so gas molecules do not have far to travel. The lungs are positioned deep inside the body to prevent excessive evaporation of the fluid that covers the respiratory surfaces. The wall of the alveolus must be covered by a thin layer of moisture because gases can diffuse into and out of the blood only when they are dissolved in blood.

Question 9

Explain the process of gas exchange

Answer 9

Oxygen enters alveolus, is dissolved into the film of moisture on the inside of the alveolus and diffuses through the membrane of the alveolus through the walls of the blood capillaries and into the pulmonary vein. Carbon dioxide then comes from the pulmonary artery, diffuses through the wall of the blood capillary into the alveolus, dissolves in the film of moisture on the inside of the alveolus. Carbon dioxide leaves the alveolus during expiration.

Question 10

Explain concentration gradient.

Answer 10

Refers to the difference in gas between the air in the alveoli and the air in the blood. It is maintained by constant blood flow through the capillaries, as blood flows the alveolus picks up oxygen and loses carbon dioxide it is replaced by more blood pumped into the capillaries. The ‘new’ blood is low in oxygen and high in carbon dioxide so the concentration gradient is maintained. Movement of air in and out of alveoli as we breathe in and out, the alveoli picks up co2 from blood and gives o2 to blood. The new air is now low in carbon dioxide and high in oxygen.

Question 11

Describe the functions of Nose and Naval Cavity

Answer 11

Filters, warms and moistens air before enters the lungs. Hairs trap dust and bacteria to prevent it from getting into lungs.

Question 12

Describe the functions of Pharynx and Epiglottis

Answer 12

Pharynx - pathway for air from nose and mouth to trachea

Epiglottis - during swallowing, closes trachea so food and liquid cannot enter the lungs.

Question 13

Describe the functions of the Larynx and Trachea

Answer 13

Larynx - Contains vocal cords. Passageway for air to travel to and from lungs.
Trachea - Leads into bronchi. Lined with cilia that beat to move mucus and trapped particles upward.

Question 14

Describe function of Bronchi and Bronchioles.

Answer 14

Bronchi - Holds the bronchioles. Main path into the lungs

Bronchioles - Holds alveoli. Ensure that incoming air is supplied to each alveolus

Question 15

Describe the functions of Alveoli and Lungs

Answer 15

Alveoli - Responsible for gas exchange. Supplied with blood capillaries for the exchange of oxygen and carbon dioxide.
Lungs - Help the oxygen from the air inhaled enter the red blood cells. Rid CO2 from the body.

Question 16

Describe the functions of the Intercostal Muscles and Diaphragm in the Respiratory System.

Answer 16

Intercostal Muscles - Move the ribcage up and out to increase volume of the lungs when inhaling.
Diaphragm - Increase volume of lungs during inhalation by contracting and flattening.

Question 17

Define circulatory system and what it transports.

Answer 17

An internal transport system that works to supply. It transports oxygen, nutrients, carbon dioxide and chemical dioxide. Blood allows substances to be carried around the body.

Question 18

What are the functions of the circulatory system?

Answer 18

• Maintains pH of body fluids.
• Distributing heat and maintaining body temp,
  Maintaining water content and ion concentration of the body fluids.
• Protecting against diseasing causing micro-organisms.
• Clotting when vessels are damaged, preventing blood loss.

Question 19

What are heart valves?

Answer 19

• Four valves in the heart
• Maintain one-way flow of blood and prevent any mixing of oxygenated and deoxygenated blood.
  Atrioventricular valves - tricuspid, bicuspid
  Semilunar Valves - Pulmonary Valve, Aortic

Question 20

Describe the Atrioventricular Valves

Answer 20

• prevent back flow of blood from ventricle to atria.
• flaps are attached to heart walls while the outer edge is supported by fibrous cords (chord tendinae) - this prevents slaps turning inside - out
  RIGHT - tricuspid (three flaps)
  LEFT - bicuspid (two flaps)

Question 21

Describe the Semilunar Valves

Answer 21

• prevent back flow of blood from the aorta and pulmonary arteries back into the heart.
  RIGHT - Pulmonary
  LEFT - Aortic

Question 22

What is the order of blood flow?

Answer 22

Vena Cava, Right Atrium, Tricuspid Valve, Right Ventricle, Pulmonary Valve, Pulmonary Artery, Pulmonary Vein, Left Atrium, Left Ventricle, Aorta

Question 23

Atrial and Ventricular Systole

Answer 23

Atrial Systole - contraction of atria, then follows and forces the remaining blood into the ventricles.
Ventricular Systole - ventricles contract and force blood into the arteries.
Systole = contraction
Diastole = relaxation

Question 24

List and describe the four cycles of blood flow

Answer 24

Cardiac - is the sequence of events that occurs none complete beat of the heart.
Pulmonary Cycle - the passage of blood flow from the right side of the heart through arteries to the lungs where it picks up oxygen and is returned to the left side of the heart by veins.
Systemic Circulation - the passage of blood from the left atrium through the left ventricle, the systemic arteries and the capillaries to the organs.
Double Circulation - continuous cycle of blood in which blood is first pumped to lungs and then to the body.

Question 25

List the differences between arteries and veins.

Answer 25

Arteries carry blood away from the heart, veins carry blood towards the heart.
Arteries have a blood pressure that increases when ventricles contract and decrease when ventricles relax, veins have a constant, relatively low blood pressure.
Arteries have thick, muscular, elastic wall. Being have thin, relatively inelastic walls with little muscle.
Arteries have no valves, Veins often have valves.

Question 26

Content of blood

Answer 26

• Blood is made up of plasma, red blood cells, white blood cells and platelets. Plasma makes up 55% of blood volume. 91% of plasma is water, the rest is made up of dissolved substances. Red blood cells are biconcave discs that hold haemoglobin, carry oxygen. White blood cells are larger cells that are responsible for fighting infections. Platelets are small cells important for normal blood clotting.

Question 27

Transport of oxygen

Answer 27

Haemoglobin is able to combine with oxygen to form a compound called oxyhemoglobin. The combination of oxygen and haemoglobin is said to be a loose one, because oxyhemoglobin can easily breakdown to release oxygen.
Hb + O2 -> Hbo2
Haemoglobin + oxygen -> oxyhaemoglobin

Question 28

Oxygenated and Deoxygenated Blood

Answer 28

The presence of haemoglobin in the red blood cells increases the oxygen carrying capacity of the blood by approximately 60 or 70 times.
Oxygenated blood is blood with a high proportion of oxyhemoglobin. Oxygenated blood in the arteries appears bright red.
Deoxygenated blood in the veins only have haemoglobin so it therefore appears dark blue.

Question 29

Why are red blood cells well suited to their function?

Answer 29

• contain haemoglobin which is able to combine with oxygen.
• have no nucleus, so there is more room for haemoglobin molecules.
• are shaped like biconcave discs- the biconcave centre increases the surface area for oxygen exchange and the thicker edges give a large volume that allows room for haemoglobin.

Question 30

Transport of Carbon Dioxide

Answer 30

• carbon dioxide the blood is carried in a number of ways. Some - about 7% or 8% - is dissolved in the plasma and carried in solution.
• another 22% combines with the global part of haemoglobin to form carbaminohaemoglobin.
• the remaining 70% is carried in the plasma as bicarbonate ions.

Question 31

Transport of nutrients and waste

Answer 31

Inorganic nutrients - transported as ions (Na+, Ca2+, K+, Cl-, I-)
Organic nutrients - required by the body (glucose, vitamins, amino acids, fatty acids and glycerol)
Wastes / metabolic wastes - need to be removed (urea, creatinine, uric acid)

Question 32

Blood Clotting

Answer 32

When there is a tear or cute, platelets go to where the cut occurred and stick to the wall. The coagulation factors joined with the platelets to block the cut and stop blood from coming out. Then fibrin, threads of insoluble protein, forms to create a mesh, known as a clot. Then clot retraction occurs and a fluid known as serum squeezes out. A scab forms over the wound.

Question 33

Describe the lymphatic system.

Answer 33

The lymphatic system is a one-way drainage system that carries lumps from tissues to general circulation.
Lymph is a clear yellow liquid that carries white blood cells, especially lymphocytes.
Function: to return excess tissue fluid to the circulation, filter out cellular material including pathogens and cancer cells, activate the immune system.

Question 34

Define transfusion

Answer 34

The transfer of blood, or of some of the components of blood, into the circulation of a person.

Question 35

Define ABO blood group system.

Answer 35

A system of classifying blood types according to the antigens on the surface of the red blood cells.

Question 36

Define antigen and antibody

Answer 36

Antigen - any substance capable of causing the formation of antibodies when introduced into the tissues.
Antibody - a substance produced in response to a specific antigen; it combines with the antigen to either neutralise it or destroy it.

Question 37

Define agglutination

Answer 37

The clumping together of micro-organisms or of blood cells.