B2: Organisation Flashcards
(38 cards)
What is a cell, a tissue, an organ and an organ system?
+ Cell: The smallest unit of a living organism
+ Tissue: A group of cells with a similar function & structure
+ Organ: A group of tissues that work together to perform a function
+ Organ System: A series of organs that work together to perform a function
In what order do the Organs of the digestive system connect (from food intake)?
Mouth → Oesophagus → Stomach → Small Intestine → Large Intestine → Anus → Rectum
Other Organs that food doesn’t pass through:
Salivary Glands, Liver, Gall bladder, Pancreas
What are the functions of each of the organs in the digestive system?
+ Mouth: To break up food
+ Salivary Glands: To produce Amylase & other digestive enzymes
+ Oesophagus: To push food down to the stomach
+ Liver: To produce Bile & filter blood (among other things)
+ Gall Bladder: To store Bile
+ Stomach: To churn & digest food with acid
+ Pancreas: To produce digestive enzymes
+ Small intestine: To digest food & absorb soluble food molecules, like nutrients
+ Large Intestine: To absorb water & produce faeces
+ Rectum: To store faeces until excretion
+ Anus: To excrete faeces
What are Enzymes?
Enzymes are Proteins that act as biological catalysts within the body, reducing activation energies for metabolic reactions.
What is the ‘Lock & Key’ Theory?
The Lock and key theory is a way of explaining enzyme activity, and it dictates that every enzyme has an active site that matches perfectly in shape to a specific substrate.
Like a lock for a key, each enzyme can only interact with the one substrate whose reaction it is designed to catalyse.
What are the three Main Enzymes for digestion, what do they do, where are they produced and where do they Act?
\+ Amylase > Breaks Carbohydrates down into simple sugars > Produced by the salivary glands & Pancreas > Used in the mouth & small intestine \+ Protease > Breaks proteins down into amino acids > Produced by the stomach & pancreas > Used in the stomach & small intestine \+ Lipase > Breaks lipids down into glycerol & fatty acids > Produced by the pancreas > Used in the small intestine
What are the two factors that primarily affect enzyme Activity, and in what way do they affect it?
+ Temperature
> The Higher the temperature of the environment, the more efficiently the enzyme works, to an extent…
> Above a certain temperature, enzymes begin to denature, and the shape of their active sites deform. This means they can no longer catalyse the reaction of their relevant substrate
> The temperature that enzymes work best in before they denature is known as the optimum temperature
+ pH
> Each Enzyme has an optimum pH level that it works best at.
> For example, enzymes that work in the stomach function best at a lower, more acidic, pH
> Outside of their optimum conditions, these enzymes work less effectively, and in extreme pH conditions, they denature
What are the two functions of Bile and where is it produced and stored?
The two functions of Bile:
+ The neutralisation of Stomach Acid
+ The emulsification of lipids
> This increases the surface area of the lipid by turning it into droplets, which allows more Lipase to catalyse its breakdown
Why do we digest food?
+ We digest food to break down large, insoluble food molecules into smaller, soluble food molecules that can be absorbed into the bloodstream via diffusion into the villi
+ These smaller food molecules are used to create new lipids, proteins, carbohydrates
+ Some of the absorbed glucose is also used for respiration
How do we test foods for Proteins, Starch & Sugars?
+ To test for the presence of proteins, use Biuret solution
> If the sample turns purple, protein is present
+ To test for the presence of sugars
> Heat for two minutes, and depending on the concentration of sugar, the solution will turn green, yellow or red
+ To test for the presence of starch, use iodine
> If the sample turns black/blue, starch is present
+ To test for the presence of lipids, use Sudan III or Ethanol
> If a red layer gathers at the top using Sudan III, lipids are present
> If, when shaken with ethanol, the food solution turns cloudy, lipids are present
What are the four main Chambers of the Heart, and how do they work to pump blood?
The four chambers of the heart are arranged in the following arrangement
Right Atrium Left Atrium
Right Ventricle Left Ventricle
+ The atriums fill with blood from the vena cava & pulmonary vein
> The heart pumps the muscles, forcing blood from the atriums into the ventricles
> The blood then pumps again, sending blood in the ventricles to the lungs and around the body through the pulmonary artery & aorta respectively
What are the five main blood Vessels of the Heart, and what do they do?
+ De-oxygenated blood from the rest of the body enters the right atrium through the VENA CAVA
+ This blood is pumped into the right ventricle, and then pumped out into the PULMONARY ARTERY, which leads to the lungs
+ At the lungs, the blood is oxygenated and returned to the heart via the PULMONARY VEIN, which connects to the left atrium
+ The oxygenated blood is pumped from the left atrium into the left ventricle, and is then pumped through to the rest of the body via the AORTA
+ There are also CORONARY ARTERIES that supply oxygenated blood to the heart
How is your heartbeat regulated?
+ The heartbeat is regulated by a group of cells known as the pacemaker, and these regulate your normal resting heart rate
> Electrical, artificial pacemakers can be used to regulate the heart rate in the event of irregularities
Why is the cardiovascular system a double circulatory system?
The cardiovascular system is a double circulatory system because for every circuit of the system, blood passes through the heart twice
How are the lungs structured?
+ The Trachea (or windpipe) splits into two tubes called bronchi, which then split into smaller tubes called bronchioles before finally ending with tiny air sacs called alveoli
+ There are millions of alveoli in the lungs
How are the lungs adapted to their function?
+ Constant Breathing maintains the steep concentration gradient of Carbon dioxide & Oxygen
+ Constant blood flow in the capillaries of the alveoli maintains the steep concentration gradient of oxygen & carbon dioxide
+ The distance between the capillaries and alveoli’s ‘air sac’ is only one cell thick, to minimise the distance of diffusion
What are the three Blood Vessels, and how are they adapted to their functions?
+ Arteries: Carry blood away from the heart. This blood is pumped at a high pressure, so…
> The vessels have thick walls to withstand the pressure
> The vessels are made of elastic fibres to withstand the pressure
> The vessels have a small lumen (cross section)
+ Veins: Carry blood from the body towards the heart. This blood is under less intense pressure, so…
> They have thin walls
> Have large lumens to facilitate an equal quantity of blood (since it is flowing at a slower pace)
> Have valves to prevent backflow
+ Capillaries: Carries blood to individual cells. This blood is under extremely low pressure, so…
> They’re only one cell thick
What is blood composed of?
+ Blood is composed of three things suspended in plasma, a fluid containing CO2, transports cells, hormones, waste etc. These are the following…
> Platelets, which work to help wounds clot
> Red blood cells, which contain haemoglobin (a substance capable of binding to oxygen), carry oxygen to cells
> White blood cells, which help fight pathogens & disease
How are Platelets, White blood cells & red blood cells adapted to their functions?
+ Red Blood Cells:
> Have no nucleus, to store more haemoglobin
> Have a biconcave shape for increased surface area, to increase the diffusion rate of oxygen
> Are small, so they can fit into capillaries
+ White blood cells
> Can change shape, to engulf pathogens and enter other cells
> Have a nucleus
+ Platelets
> Are fragments of cells, which gather in large numbers to clot wounds
> Do not have a nucleus
What is Cardiovascular Heart Disease (CHD)?
Cardiovascular heart disease is the buildup of fatty deposits in the coronary arteries, narrowing them, causing a reduced blood flow and reduced supply of oxygen to the heart. (This buildup is known as Atherosclerosis)
What are the two ways that CHD can be treated?
CHD can be treated in two ways…
+ Using Stents: Stents are small metal wire grids that are surgically implanted into the coronary arteries and expanded, causing the fatty deposits to be pushed back and the artery widened.
> Pros: Keep you alive
: Cons: Require surgery, cause build up of scar tissue, require blood clot preventing drugs
+ Using Statins: Statins are drugs that reduce the amount of harmful cholesterol, limit the liver’s production of cholesterol and reduce the rate it is deposited. This helps prevent the development or worsening of heart disease.
> Pros: Cheap & do not require surgery
> Cons: May have side effects & people may forget to take them
What are the two ways Blood Valves can be faulty?
+ Leaky Valves: Valves cannot close properly, and backflow in veins occur
+ Stiff/stuck valves: Valves do not open fully, or require more effort to open
> Both of these conditions mean more effort is required to circulate blood
> This places stress on the heart (Symptoms of this can be shortness of breath, swelling in the feet & ankles as well as unusual tiredness)
+ Faulty valves can be replaced with animal or artificial replacements
Cardiovascular Disease can lead to Heart failure. What are the two ways heart failure can be treated?
+ Donor Hearts: A heart transplanted from someone else
> Pros: Won’t wear down, function like the replaced organ
> Cons: Requires a suitable donor, the organ will be rejected if immunosuppressants are not taken, making the patient more susceptible to infections
+ Artificial Hearts: Machinery used to keep people with poor hearts alive while a donor is not available, or if their heart needs to rest & recover
> Pros: Can be used when a donor is not available
> Cons: Short term (eventually wears out), requires an electrical supply
How do some diseases interact to provoke illness?
+ Immune system defects mean some are more susceptible to disease (HIV)
+ Viruses in cells can trigger cancers to form
+ Immune reactions to pathogens can cause allergic reactions (i.e. rashes, asthma)
+ Severe illness can lead to other mental illnesses like depression
