B2-Organisation & digestive system Flashcards
What makes up a TISSUE?
A group of similar cells makes up a TISSUE
What makes up an ORGAN?
A group of tissues makes up an ORGAN
What makes up an ORGAN SYSTEM?
A group of organs makes an ORGAN SYSTEM
Name some organ systems and organs included in them.
Circulatory: heart, veins, arteries Respiratory: Lungs, trachea, diaphragm
Digestive: Stomach, small intestines, mouth etc
Nervous: Brain, spinal chord
Skeletal: Bones Reproductive: Penis, testes, ovaries, vagina
Name some Tissues and their functions
Muscular - contracts to bring about movement
Glandular - contains secretory cells that can produce and release substances like enzymes or hormones
Epithelial - covers the outside of our bodies as well as internal organs
Food tests:
What do these nutrients need and show if the result is positive?
- Starch
- Fat
- Simple sugar
- Protein
Starch Testing reagent - Iodine solution NO HEAT is required Positive result shows blue-black
Fat Testing reagent - Ethanol NO HEAT is required Positive result shows - Oil drops form at surface
Simple Sugar Testing reagent - Benedict’s solution HEAT IS REQUIRED Positive result shows - Orange (brick-red)
Protein Testing reagent - Biuret A or B reagent NO HEAT is required Positive result shows - pale lilac
What is Digestion?
Digestion is the breakdown of large insoluble molecules into small soluble ones.
Name organs in the digestive system.
Mouth
Salivary glands
oesophagus
liver
stomach
gallbladder
pancreas
small intestine
large intestine
rectum
anus
What is the function of the MOUTH?
It’s the FIRST stage in MECHANICAL DIGESTION.
Food is broken up into smaller pieces and mixed with saliva.
Saliva contains ENZYMES and helps lubricate food so it can be SWALLOWED and DIGESTED.
What is the function of the Oesophagus?
A wave of muscular construction called PERISTALSIS moves food from mouth to stomach.
What is the function of the stomach?
Thick muscular walls which churns the food - further broken down. It secretes HCl (hydrochloric acid) which creates the correct pH for activating enzymes and kills any microbes we might have consumed.
What is the function of the Small Intestine?
Where the small soluble molecules get absorbed in the blood.
The walls of the small intestine are highly folded into villi . This gives a large surface area .
They have a good blood supply so short diffusion distances.
Muscular walls squeeze undigested food to the large intestine.
What is the function of the Large Intestine?
Where water and electrolytes are absorbed back into the body.
Formation of faeces
What is the function of the rectum?
Stores faeces
What are Enzymes?
Enzymes are biological catalysts - they speed up chemical reactions but do NOT get used up. They are made of PROTEIN. They catalyse different metabolic reactions: • build up large molecules i to smaller ones • break up large molecules •change one molecule into another
What shape do enzymes have?
Enzymes have a very specific shape.
The part of the enzyme to which the substrate binds is called the active site. (most important part of the enzyme).
The enzyme is the lock, and the substrate is the key.
What is the SUBSTRATE?
It’s the molecule (‘key’) that the enzyme (‘lock’) works on.
What is an ACTIVE SITE?
The specific part of the enzyme (lock) that the substrate (key) fits into.
What happens after the enzyme has finished working on the SUBSTRATE?
It leaves PRODUCTS these are products of the broken down substrate.
How do the enzyme and substrate fit together?
The enzyme and substrate fit together like a lock and a key.
enzyme is the lock and the substrate is the key
What do enzymes only work in and require?
Enzymes only work in specific conditions.
They need a specific temperature and pH.
What is the optimum temperature?
This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells.
Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.
What does it mean if the enzyme has a low rate of reaction?
This means the particles do not have as much kinetic energy.
What happens when an enzyme becomes denatured (e.g. high body temperature)?
The enzyme has changed shape - the active site and substrate no longer fit together. This is IRREVERSIBLE.
What happens when the enzyme Amylase is added to Starch?
Starch turns into Simple Sugars (glucose).
What does ‘ase’ mean on the end of a word.
It means it’s an enzyme. E.g. Protease
What happens when the enzyme Protease is added to Protein?
Protein turns into Amino acids.
What happens when the enzyme Lipase is added to Fat (Lipids)?
Fats turn into Glycerol + Fatty acids.
Where is the digestive enzyme Amylase produced?
- Pancreas
- Salivary glans
- Small Intestine
Where is the digestive enzyme Protease produced?
- Pancreas
- Stomach
- Small Intestine
Where is the digestive enzyme Lipase produced?
- Pancreas
- Small Intestine
Where does the digestive enzyme Amylase work?
- Mouth
- Small Intestine
Where does the digestive enzyme Protease work?
- Stomach
- Small Intestine
Where does the digestive enzyme Lipase work?
Small Intestine
What is Bile?
It is a greenish-yellow liquid that is produced in the liver and stored in the gallbladder. It then travels via the bile duct into the small intestine
recap of
red blood cells
white blood cells
platelets
plasma
and main functions
What two functions does Bile have?
- It is an alkali so it neutralises the food coming from the stomach.
- It emulsifies fats - breaks them into smaller droplets so there is a larger surface area for lipases to work on.
What percentage of the blood is plasma?
55%
What percentage of the blood is white blood cells + platelets?
<1%
What percentage of the blood is red blood cells?
45%
What is the shape and function of red blood cells?
Biconcave shape to increase surface area –
Transport oxygenated blood from the lungs to cells around the body.
What do red blood cells not have that most cells have and why?
NO nucleus to carry as much oxygen as possible.
What molecule does oxygen bind to on the red blood cells?
Haemoglobin
What does haemoglobin do?
- It gives the red pigment to the blood cells.
- Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body’s tissues and returns carbon dioxide from the tissues back to the lungs.
What happens when oxygen is bound to haemoglobin?
It forms oxyhaemoglobin (bright red colour). Haemoglobin can combine reversibly with oxygen.
What happens when oxygen is delivered to the cells?
The oxygen leaves haemoglobin - this is called deoxyhaemoglobin (dark red).
What is a white blood cell in comparison to a red blood cell?
A white blood cell has a nucleus and is larger than a red blood cell.
What are white blood cells function?
They fight of pathogens.
What are Platelets and their function?
- Platelets are cell fragments produced by giant cells in the bone marrow.
- They have NO NUCLEUS.
- Their function is that they are important in helping your blood to clot at the site of a wound.
What are the two main ways that platelets carry out their function and stop bleeding?
- They have proteins on their surface that enable them to stick to breaks in a blood vessel and clump together.
- They secrete proteins that result in a series of chemical reactions that make the blood clot, which plugs a wound.
How do white blood cells carry out their function?
- Engulfing pathogens
- Producing antibodies
- Producing toxins
What is plasma?
- light yellow liquid, similar to the colour of straw
- Along with water, plasma carries salts and enzymes.
What is the function of plasma?
Transports everything you need (utrients, hormones, and proteins) and waste products around your body.
How does plasma carry out this function?
Contains nutrients, proteins, waste products, gases, hormones and all types of blood cells.
Name the double circulatory system
REMEMBER
Arteries is…
Veins is…
Capillaries…
away from the heart (e.g. aorta)
towards the heart (e.g. vena cava)
connect arteries and veins (embedded in tissues for oxygen diffusion)
Name the parts of the heart.
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle
- Vena Cava
- Aorta
- Pulmonary artery
- Pulmonary vein
- Cardiallic muscle
- Pace maker
What features do arteries have?
- Narrow cavity/lumen - Helps to maintain pressure away from the heart.
- Thick walls (muscle tissue) - To resist the high blood pressure.
- Thick layer of elastic tissue - Allows arteries to stretch when blood is pumped and flows at high pressure and the recoil at low pressure.
What features do veins have?
- Thin walls - Blood flows at very low pressure, walls don’t need to be strong.
- Valves present - Blood at low pressure, sometimes moving against gravity. They help to prevent blood from flowing backwards.
- Wide lumen - It offers less resistance to the flow of blood
- Thin layer of elastic tissue - As pressure is low and there are almost no fluctuations, no need to stretch and recoil.
What features do capillaries have?
- Walls are one cell thick - The distance for substances to diffuse is shorter so faster diffusion.
- The cavity has the diameter of one red cell - All red cells in contact with capillary wall, so more surface for diffusion of oxygen.
- Also, it allows time for oxygen to diffuse out of red cells.
Name the parts of the respiratory system.
Nose
Mouth
Trachea
Bronchi
Diaphragm
Intercostal muscle
Rib
Lung
Bronchioles
Alveoli
Percentage of Nitrogen breathed in and out?
% breathed in - 80%
% breathed out - 80%
Percentage of Oxygen breathed in and out?
% breathed in - 20%
% breathed out - 16%
Percentage of Carbon Dioxide breathed in and out?
% breathed in - 0.04%
% breathed out - 4%
Percentage of water vapour breathed in and out?
% breathed in - variable
% breathed out - saturated
What does Ventilation do?
Moves air in and out and helps maintain a steep concentration gradient.
