The Respiratory and Circulatory System Flashcards
Structure of the Respiratory System
Air enters the nose and mouth, convoluted lining and mucous membranes in the nose and nasal cavity warm and humidify the air. Hairs and muscous lining the nose traps debris. Air travels throug the pharynx before being diverted into the trachea by the epiglottis.
Pharynx
Region from the nasal cavity to the top of the trachea.
Epiglottis
Flap of elastic cartilage that covers the oesophagus during inhalation and covers the larynx during swallowing.
Larynx
Cartilage structure containing the vocal cords (mucous membranes that vibrate when air passes through).
Trachea
Made up of ‘C’ shaped cartilage rings that hold the structure open, ensuring that air can constantly pass. As its base, it splits into 2, each branch for each lung. The epithelial lining produces mucous trapping debris, where the cilia lining moves in wave like motions to take mucous and debris to pharynx to be swallowed.
Bronchi
At the end of the trachea, it splits into 2 primary bronchi, one for each lung. They split into secondary bronchi, which take air into each lobe of the lung. These than split into tertiary bronchi. The structure of bronchi is similar to trachea.
Bronchioles
The tertiary bronchi divide into bronchioles, which then split into terminal bronchioles. They don’t contain cartilage but rather smooth muscle, allowing them to control air flow to lungs, expanding when the body needs more oxygen. Cilia and mucous is also present.
Lungs
The lungs take up the entire chest cavity except for the space between them called the mediastinum. Each lung is divided into lobes, the left having 2 and the right having 3. The pleura (a membrane) covers the surface of the lungs (visceral pleura) and lines the inside of the chest (parietal pleura). Between these 2 layers is pleural fluid, which holds the lungs against the chest and allows them to slide. Inside the lungs, the smallest bronchioles open into clusters of tiny air sacs called alveoli. Each alveolus has a wall only one cell thick, and is surrounded by a network of blood capillaries, where gases move between the blood in the capillaries and air in the alveoli.
Nasal Cavity
Contains projections that increase the surface area. Filters, warms and moistens air. Contains smell receptors. Resonating chamber for speech, and hairs and mucous trap debris.
Intercostal Muscles
Muscles between ribs. They move the ribcage upward and outwards to increase the volume of the chest cavity.
Diaphragm
Muscle that separates the chest from the abdomen. it contracts and flattens downwards, increasing chest volume.
Ribs
Framework of the chest.
Ventilation
The process by which air is moved in and out of the lungs (air flows from a place of higher pressure to lower pressure, therefore, air flows into and out of lungs due to pressure difference).
Inspiration
The process of taking air into the lungs. To lessen the pressure inside the lungs, their volume must increase. To do this, the diaphragm and external costal muscles contract. The diaphragm becomes flatter and rib cage moves upwards and outwards, increasing the volume of the chest cavity. As the pleura adheres to the internal wall of the chest cavity, the lungs expand with the chest cavity. Due to the lower pressure created, air flows in via the trachea.
Expiration
The process of breathing out. The diaphragm and external costal muscles relax, so the diaphragm bulges into the chest cavity and the rib cage moves downward. This reduces the volume of the chest cavity, and lungs but increases air pressure in the lungs. Air flows out to have equilibrium.
Structure of the Lungs and Gas Exchange
- The alveoli’s give the lungs a large internal surface area so that large amounts of gases can be exchanged in a shorter period of time.
- Each alveolus has as much blood as possible close to the air in the alveolus, to maximise speed.
- The continuous flow of blood helps to maintain a concentration differential of oxygen and carbon dioxide between the blood and the air in the lungs.
- The wall of the alveolus is one micrometre thick so that gas molecules don’t have to move far when moving in and out of blood.
- The membrane of the alveolus is covered in a thin layer of moisture, as gases can diffuse into and out of the blood only when dissolved.
The Process of Gas Exchange
- Deoxygenated blood in the capillaries surrounding the alveoli is brought to the lungs by the pulmonary arteries.
- Oxygen dissolves in the moisture inside the alveolus and diffuses through into the blood, at the same time that carbon dioxide diffuses from the blood into the air (higher concentration then the air).
- This process happens due to a concentration gradient which is maintained by the constant flow of blood to the capillaries and the movement of air into and out of the alveoli as we breath in and out.
Emphysema
Disease caused by long term exposure to irritating particles. It can damage the alveoli, lessening the surface area of the lung. Because of the loss of elasticity, the lungs are constantly inflated, and breathing out becomes voluntary. Can’t be cured and only worsens.
Lung Cancer
Development of a mass of cells that divides uncontrollably in the lungs. tabacco and asbestos contains initiators and promotors of lung cancer. Most of the time, it begins in the bronchi, causing a mass production of mucous. Cells at the base divide more rapidly and the mucous becomes trapped, causing a rupture in the alveoli. Then a growth develops.
Lung Infections
Pneumonia is an infection. The inflammation causes secretion of fluid and mucus into alveoli, reducing air they contain and reducing surface area. Tuberculosis is an infection by the bacterium ‘mycobacterium tuberculosis.’ It is spread by droplets and hygiene prevents it.
Asthma
Difficulty breathing due to narrowing of the airways due to the bronchioles spasming. This occurs due to the smooth muscles contracting, inflammation causing the lining of the airways to thicken and mucus filling the airway. It can be an allergic and non-allergic response. Usually irritation causes mass mucus production, reducing the volume of air going in and out.
Circulatory System
The link between the cells inside the body and the environment outsides (to meet the cells requirements).
Blood
Is the transport link between the cells of the body systems. Some of its functions is to:
1. transport oxygen and nutrients to cells
2. Transports waste away
3. Transport hormones to cells
4. Maintain pH of body fluids
5. Distributing heat (maintaining body temp)
6. Maintaining water content and ion concentration in fluids
7. Protecting against disease
8. Clotting when vessels damage
Structure of Blood
Composed of 55% plasma, 41% erythrocytes, and 4% leucocytes and thrombocytes.
Plasma
Mixture of water and dissolved substances such as salts and sugars. It transports the components of blood, including cells, nutrients, wastes, hormones, proteins and antibodies throughout body.
Erythrocytes
Red blood cells. They have biconcave shape. They don’t have a nucleus, making them more flexible but limiting their lifespan to 120 days. Their function is to transport oxygen from the lungs to cells.
Leucocytes
White blood cells. Plays a role in protecting the body from infection. The different types are neutrophils, monocytes, lymphocytes, basophils and eosinophils.
Thrombocytes
Platelets. Small fragments of cells.
Neutrophils
Contains enzymes to digest pathogens.
Monocytes
Form other cells, like macrophages.
Lymphocytes
Involved in the immune response, cell mediated immunity uses T-lymphocytes and antibody mediated immunity used B-lymphocytes.
Basophils
Responsible for allergic reactions, producing heparin and histamine.
Eosinophils
They are inflammatory responses for larger parasites.
Transport of Oxygen
Oxygen is not soluble, so only 3% is carried as solution. The rest is combined with haemoglobin to form oxyhaemoglobin (Hb + O2 = HbO2). This happens where the concentration is relatively high (at capillaries of the lungs). Oxyhaemoglobin breaks down into haemoglobin and oxygen when the concentration is low (the capillaries between body cells). Oxygenated blood is high with oxyhaemoglobin, which gives it that bright red colour.
Transport of Carbon Dioxide
- 8% of carbon dioxide is dissolved in the plasma and carried in solution. The alveoli is surrounded by capillaries, here the CO2 dissolved in plasma diffuses into the air.
- 22% combines with haemoglobin to form carbaminohaemoglobin. The carbaminohaemoglobin breaks down and the CO2 molecules released diffuse into the alveolus.
- 70% is carried in the plasma as HCO3 (CO2 + H2O = carbonic acid = hydrogen ions + bicarbonate ions). Hydrogen ions and bicarbonate ions recombine to from carbonic acid, which then breaks down under enzyme action into water and CO2, which diffuses into alveolus.
Transport of Nutrients and Waste
They are dissolved and transported in the blood plasma. Inorganic nutrients are transported as ions. organic nutrients are dissolved in the blood plasma.
When and Injury Occurs that Injures Blood Vessel…
- Vasoconstriction
- Platelet plug
- Coagulation
(When Injury Occurs) Vasoconstriction
The muscles in the walls of the small arteries that have been injured constrict to reduce blood loss.
Platelet Plug
The internal walls of the blood vessels are normally very smooth, but any damage creates a rough surface to which platelets stick, which attracts more, creating a plug. The platelets release substances that act as vasoconstrictors, which enhance and prolong the constriction of damaged vessels.
Coagulation
For more serious injuries. The formation of a blood clot involves clotting factors. they result int he formation of fibrin that forms a mesh that traps blood cells, platelets and plasma. This then forms the clot (thrombus). Then clot retraction occurs.
Clot Retraction
The network of fibrin contract, pulling the edges of the damaged blood vessels together. As it occurs, a fluid known as serum is squeezed out. The clot then dries, forming a scab that prevents entry of microorganisms.
The Heart
- Pumps blood.
- It is located between the 2 lungs in the mediastinum, behind and slightly left of the sternum, and the size of a human fist.
- It is enclosed in a membrane called the pericardium, holding the heart in place but allowing it to move as it beats.
- The walls of the heart is made up of cardiac muscle.
- The heart is split by a septum. The right side collects deoxygenated blood and sends it to lungs, the left side collects blood from lungs and pumps it to the body.
Circulation Through Lungs
As deoxygenated blood flows through the capillaries of the lungs, oxygen diffuses from the air into the blood, and carbon dioxide diffuses from the blood into the air. Blood becomes oxygenated.
Circulation Through Body
As oxygenated blood flows through the capillaries of the body, oxygen and nutrients diffuse from the blood into the body cells, and carbon dioxide and other wastes diffuse from the cells into the blood. Blood becomes deoxygenated.
Aorta
Largest artery. Takes blood from the left ventricle to body.
Pulmonary Vein
Brings blood from the lungs to the left atrium. There are four, two for each lung.
Semilunar Valve
Stops blood from flowing back into the ventricles when they relax. Each valve has 3 cusps. When blood flows into the artery, the cusps are pressed flat against the artery wall. When blood tires to flow back into the ventricles, the cusps fill out and seal off the artery.
Left Atrium
Receives blood from the lungs and passes it to the left ventricle.
Left Atrioventricular Valve
Bicuspid. Prevents backflow of blood from the left ventricle into left atrium during ventricular systole.
Papillary Muscle
It contracts to pull chordae tendineae and open atrioventricular valves during atrial systole.
Left Ventricle
Pumps oxygenated blood into aorta towards body.
Septum
Heart muscle that separates the left and right sides of the heart.
Right Ventricle
Pumps deoxygenated blood into the pulmonary artery towards the lungs.
Chordae Tendineae
Prevents atrioventricular valves from inverting during ventricular systole.
Right Atrioventricular Valve
Tricuspid. Prevents backflow of blood from right ventricle, into right atrium during ventricular systole.
Inferior Vena Cava
Major vein returning deoxygenated blood from legs, abdomen, liver and kidneys.
Right Atrium
Pushes deoxygenated blood into the right ventricle.
Superior Vena Cava
Major vein returning deoxygenated blood from head and arms.
Pulmonary Trunk
Divides into 2 pulmonary arteries that carry deoxygenated blood to each lung.
Circulation
The movement of blood through the heart and blood vessels.
Arteries
Blood vessels that carry blood away from the heart. When the ventricles relax, the elastic artery walls recoil, which keeps the blood moving and maintains pressure. They can divide into arterioles, which supply blood to the capillaries.
Capillaries
Link between arteries and veins. They are microscopic blood vessels that form a network to carry blood to most cells, enabling cells to get their nutrients and rid their wastes.
Veins
Carry blood to heart. Capillaries join to small veins (venules), which then join up to make larger veins. Blood pressure in the veins is relatively low because the blood loses most of its pressure as it flows through the capillaries, therefore the wall of the veins are thinner, and the pressure is constant. They have valves to make sure there’s no backflow.
Catering to Change
To cater to change, the blood flow must be able to change by changing the output of blood from heart, and by changing the diameter of the blood vessels supplying tissues.
Cardiac Cycle
Or heartbeat, is the sequence of events that occurs in one complete beat of the heart. The heart muscle contracts (systole) then the muscle relaxes (diastole), the ventricules and atrium’s follow a similar pattern, though different.
Cardiac Output
Cardiac output (mL/min) = stroke volume (mL) * heart rate (beats/min).
Stroke Volume
Volume of blood forced from a ventricle in the heart with each contraction.
Heart Rate
Number of times the heart beats per minute.
Antigens and Antibodies
The surface of red blood cells is coated with sugar and protein molecules that are able to stimulate the immune system. These are called antigens, and the body produces antibodies for a specific antigen. When they combine, the antigen is neutralised/destroyed.
Blood Groups
There are two sugar antigens involved in ABO classification antigen A and B. Thus, there are four groups. A (antigen A), B (antigen B), AB (both) and O (neither). The antibody that reacts against antigen A is called anti A, and so on. A persons immune system is able to recognise their own antigens. A person with A will produce anti-B, group B produces anti-A, group both produces neither and group O produces both. The Rh is protein antigens. A person with this is Rh+. A person without this produces Rh antibodies.
Transfusions
Transfers blood, or one of its components, from one person to another. Mixing of incompatible blood types can cause the erythrocytes to agglutinate (clump). There is whole blood transfusions, red cell concentrate transfusions, platelet concentrates transfusions, cryoprecipitate transfusions, immunoglobulins transfusions and autologous transfusion.
Whole Blood Transfusions
Blood taken with added chemical to prevent clotting.
Red Cell Concentrate Transfusions
Produced by spinning blood in centrifuge. The heavier cells sink, leaving the plasma on top. Both materials are used.
Platelet Concentrates Transfusion
Given to patients with abnormal platelets or less.
Cryoprecipitate Transfusions
It is obtained by freezing plasma and thawing it slowly. When it has thawed, the cryoprecipitate remains solid, containing many of the substances need for clotting (can treat haemophilia).
Immunoglobulin Transfusions
Group of proteins that act as antibodies. They are extracted and given to those antibody deficient. Particular immunoglobins from certain donors are used to treat patients with no immunity to a particular disease.
Autologous Transfusion
When the own patients blood is used, collected prior an operation that may require it.
Function of the Lymphatic System
Is to collect some of the fluid that escapes from the blood capillaries due to the high pressure and returning it to the circulatory system. It also acts as defence against disease causing organisms. The fluid is called lymph. This system doesn’t circulate, and is one way.
Structure of the Lymphatic System
Consists of a network of lymph capillaries joined to larger lymph vessels (lymphatics) and consists of lymph nodes.
Working of the Lymphatic System
The lymph vessels originate as blind ended tubes in the spaces between the cells of most tissues. Lymph capillaries are more permeable, proteins and disease causing organisms in the intercellular fluid can easily pass. The network of lymph vessels joins to form 2 lymphatic ducts that empty the lymph into large veins in the upper chest. Lymph is moved by the contraction of smooth muscle with the additional help of skeletal muscle, which propels the lymph forward. Because there is no pump, the larger lymph vessels have valves in case the pressure drops.
Lymph Nodes
Lymph glands. Occur at intervals along the lymphatic system vessels, though most numerous in the neck, armpits, groin and around the alimentary canal. Lymph nodes are surrounded by a capsule of connective tissue, within this is lymphoid tissue that contains lymphocytes, macrophages and plasma cells. Lymph filters through and passes several other nodes before entering the circulatory system.
The Lymphatic System and Defence Against Disease
Lymph entering the nodes contains cell debris, foreign particles and microorganisms. Larger particles are trapped in the meshwork of fibres as lymph flows through the spaces in the nodes. Large phagocytic cells called macrophages destroy these particles by ingesting them via phagocytosis (projections from the macrophage surround the particle and take it into the cell, where its destroyed by enzymes). When infections occur, the formation of lymphocytes increase, causing the lymph nodes to become swollen and sore.
