Exchange And Transport Systems Flashcards
Tidal volume is
The volume of air in each breath
Ventilation rate is
The number of breaths per minute
Forced expiratory volume
The maximum volume of air that can be breathed out in one second
Forced vital capacity
The maximum volume of air it is possible to breathe forcefully out of the lungs after a really deep breath in
How is TB caused
Bacteria
How does TB affect the body
When someone’s becomes infected with tuberculosis bacteria, immune system cells build a wall around the bacteria in the lungs. This forms small, hard lumps known as tubercles. Infected tissue within the tubercles died and the gaseous exchange surface is damaged, so tidal volume is decreased.
Symptoms of TB
Persistent cough Coughing up blood Mucus Chest pains Shortness of breath (increased ventilation rate) Fatigue
What is fibrosis
The formation of scar tissue in the lungs
Structure of gills
Water containing oxygen enters the fish through its mouth and passes through the gills. Each gill js made of lots of thin plates called gill filaments which give a large surface area for exchange of gases. The gill filaments are covered in lots of lamallae which increase the surface area even more. The lamallae have lots of blood capillaries and a thin surface layer of cells to speed of diffusion between water and the blood
Counter current system
In the gills of a fish, blood flows through the lamellae in one direction and water flows over them in the opposite direction. This is called a counter current system. The counter current system means that water with a high oxygen concentration always flows next to blood with a lower concentration of oxygen. This in turn means that a concentration gradient between water and blood is maintained over the whole length of the gill. So as much oxygen diffuses from the water into the blood as possible
Main gas exchange surface in a lead
Mesophyll layer
Gas exchange in insects
Air moves into the trachea from the spiracles. Oxygen travels down the concentration gradient towards cells. The trachea branch off into tracheoles which go into individual cells. Oxygen diffuses directly into resourcing cells. Carbon dioxide moves down the concentration gradient towards the spiracles where it’s released into the atmosphere. Insects use rhythmic abdominal movements to move air in and out of the spiracles
Lung structure
Trachea
Bronchus
Bronchioles
Alveoli
What happens during inspiration
External intercostal and diaphragm contract. Ribcage moves up and out. Diaphragm flattens Increases volume in thorax Lung pressure decreases Air is drawn in
What happens in expiration
External intercostal muscles and diaphragm relax Ribcage moves in and down Diaphragm curves upwards Volume in thorax decreases Air pressure in thorax increases Air is forced out
Movement of oxygen through the lungs
Trachea Bronchi Bronchioles Alveoli Alveolar epithelium Capillary endothelium Blood
How is fibrosis caused
Infection or exposure to dust
How does fibrosis affect the lungs
Scar tissue is thick and less elastic than normal long tissue so the lungs cannot expand as much - they can’t hold as much air. Tidal volume reduce and forced vital capacity is reduced
Symptoms of fibrosis
Faster ventilation rate Shortness of breath Dry couch Chest pain Fatigue Weakness
Asthma is caused by
Allergic reaction
What happens to the lungs during asthma attacks
Smooth muscle lining the bronchioles contract and large amount of mucus is produced. Causes constriction of the airways. Oxygen in lungs is reduced so reduced forces expiratory volume
Asthma symptoms
Wheezing
Tight chest
Shortness of breath
Cause of emphysema
Smoking or long term exposure to air pollution. Foreign particles in the smoke become trapped in the alveoli which causes inflammation. Phagocytes gather at this area which produce an enzyme that breaks down elastin
Symptoms of emphysema
Shortness of breath
Wheezing
Increased ventilation rate
How does amylase break down starch
Amylase works by catalysing hydrolysis reactions that break the glycosidic bonds in starch to produce maltose.
Where is amylase produced
Salivary glands and pancreas
Membrane bound disaccharides are
Enzymes that are attached to the cell membranes of epithelial cells lining the ileum
What do membrane bound Disaccharides do
They help to break down disaccharides into monosaccharides , this involves the hydrolysis of glycosidic bonds
Glucose + fructose
Sucrose
Glucose + glucose
Maltose
Glucose + galactose
Lactose
What do lipase do
Catalyse the breakdown of lipids into monoglycerides and fatty acids. The involves the hydrolysis of an ester bond in the lipid
Where is lipase found
Pancreas - secreted into the small intestine
Where are bile salts made
Liver
What do bile salts do
Emulsify lipids. They cause the lipids to form small droplets. Several small droplets have a bigger surface area than a single large droplet so the formation of small droplets greatly increases the surface area of lipid that’s available for lipase to work on. Once the lipid has been broken down by lipase, the monoglycerides and fatty acids stick with the bile salts to form micelles
What do micelles do
Help the products of lipid digestion to be absorbed
Endopeptidases act to hydrolyse peptide bonds where on the protein
Within the protein
Exopeptidases act to hydrolyse peptide bonds where in the protein
At the end of the protein - they remove single amino acids from proteins
What are dipeptidases
Dipeptidases are exopeptidases that work specifically on dipeptides. They act to separate the two amino acids that make up a dipeptide by hydrolysing the peptide bond between them
How is glucose absorbed
Glucose is absorbed by active transport with sodium ions via a cotransporter protein
How is galactose absorbed
Galactose is absorbed by active transport with sodium ions via a cotransporter protein
How is fructose absorbed
Fructose is absorbed via facilitated diffusion through a transporter protein
How are monoglycerides and fatty acids absorbed
Micelles help to move monoglycerides and fatty acids towards the epithelium. Micelles constantly break up and reform so they can released the monoglycerides and fatty acids allowing them to be absorbed. Micelles are not taken up across the epithelium. Monoglycerides and fatty acids are lipid soluble so can diffuse directly across the epithelium cell membrane
How are amino acids absorbed
sodium ions are actively transported out of the epithelial cells into the ileum. They then diffuse back into the cells through sodium dependent transporter proteins in the epithelial cell membranes carrying amino acids with them
Structure of haemoglobin
Haemoglobib is a large protein with a quaternary structure. Each chain has a harm group which contains an iron on and gives haemoglobin its red colour. Each molecule of haemoglobin can carry four oxygen molecules
How does haemoglobin transport oxygen around the body
In the lungs oxygen joins to haemoglobin in red blood cells to form oxyhemoglobin during association. Oxygen unbinds to haemoglobin during dissociation
What is affinity for oxygen
Affinity for oxygen means the tendency a molecule has to bind with oxygen
High partial pressure means high affinity for oxygen
Low partial pressure means low affinity for oxygen
High partial pressure of carbon dioxide in a cell means
More oxygen is released into cell
The cardiac cycle
The ventricles are relaxed. The atria contract, decreasing the volume of the chambers and increasing the pressure inside the chambers. This pushes the blood into the ventricles. There’s a slight increase in ventricular pressure and chamber volume as the ventricles received the ejected blood from the contracting atria
The atria relax. The ventricles contract, decreasing their volume and increasing their pressure. The pressure becomes higher in the ventricles than the atria which forces the atrioventricular valves shut to prevent back flow. The semi lunar valves are forced open
The ventricles and the atria relax. The higher pressure in the pulmonary artery and aorta closes the semi lunar valve to prevent back flow into the ventricles. Blood returns to the heart and the atria fill again due to the higher pressure in the vena cava and pulmonary vein. In turn this starts to increase the pressure of the atria. As the ventricles continue to relax, their pressure falls below the pressure of the atria and so the atrioventricular valves open. This allows blood to flow passively into the ventricles from the atria
The inner lining of arteries are folded because…
They allow the artery to stretch
Why do veins contain valves
To prevent back flow
Water movement in a plant - cohesion tension theory
Water evaporates from the leaves at the top of the xylem during transpiration. This creates tension which pullls more water into the leaf. Water molecules are cohesive so when some are pulled into the leaf, others follow. This means the whole column of water in the xylem from the leaves down to the roots moves upwards. Water then enters the stem through the roots
How does light intensity affect transpiration
The lighter is is the faster the transpiration rate is because the stomata open when it gets light to let in CO2 for photosynthesis
What is a gas exchange surface
Boundary between the outside environment and the internal environment of an organism
What happens to the body during forced expiration
External intercostal muscles relax
Internal intercostal muscles contract
Ribcage pulled down and in even more
What does elastin do
Help alveoli recoil to their normal shape after inhaling and exhaling air
