Theme 1: The Digestive System Flashcards
What is the digestive system?
The digestive is how the human body gains all it’s nutrients and energy from ingested food
contains many structures and organs that each have their role in digesting food, absorbing and converting nutrients ready for transportation around the body.
Label bitch
A - mouth
B - liver
C - gall bladder
D - small intestine
E - appendix
F - rectum
G - anus
H - large intestine
I - pancreas
J - stomach
K - oesophagus
L - salivary glands
What are macro-nutrients?
large molecular nutrients
** carbohydrates, proteins and fat **
Gained from food
What are simple carbohydrates?
Simple carbohydrates or sugars are referred to as monosaccharides.
Monosaccharides are the simplest form of carbohydrates and as such can be easily absorbed by the body for energy and calorie use. Glucose, fructose and galactose (milk sugar) are examples.
What are disaccharides?
Disaccharides is when two simple sugars link up together.
Sucrose which is often referred to as table sugar is made up of one glucose linked to one fructose. Maltose is when two glucose link together.
Simple sugars link together via glycosidic bonds.
What are complex carbohydrates?
Complex carbohydrates is when a chain of carbohydrates is formed.
They can either be chained in rows such as oligosaccharides which are found in soybeans.
Or they can be in chains with branches of them which are called polysaccharides, such as starch.
Polysaccharides can be broken down by enzymes to form monosaccharides (Amylase breaks the glycosydic bonds through the act of hydrolysis)
What are proteins?
Building blocks for most structures
Proteins are made up of amino acids that are bound together by peptide bonds
Protein can form into complex structures from enzymes, hormones or carrier proteins as examples. The human body only needs 20 amino acids to maintain body function
What are the three groups of proteins>
Non-essential - can be gained from food or made by ourselves.
Conditionally essential - can be made when we are well nourished, but they cannot be made when the body is starved.
Essential - can only be got from food.
What are fats?
Fats are made up of chains of fatty acids attached to a glycerol backbone
When a glycerol backbone meets one fatty acid, they can joined together to make a monoglyceride. If two fatty acids join a glycerol backbone it will become a diglyceride. And three fatty acids joined to the glycerol backbone is a triglyceride.
What are saturated fats?
The saturated status of fats is a result of how many hydrogens are bound to the fatty acid chain, which results in the formation of single bonds between the fatty acids.
This often results in saturated fatty acid chains being long and straight, thus easier to pack together.
This means that anything with high amounts of saturated fat can remain solid at room temperature, such as butter.
What are unsaturated fats?
Unsaturated fats have less hydrogen bound to the fatty acid chain as a result of double bonds replacing hydrogen.
The more double bonds there are, the less hydrogen is bound to the fatty acid chain.
Because of the double bond, the chain also bends or kinks in another direction.
This means that unsaturated fats do not pack together as well, resulting in unsaturated fats being more liquid at room temperature.
What are monounsaturated fats?
If unsaturated fats have one double bond, they are called monounsaturated fats. If they have more than one double bond, they are referred to as polyunsaturated fats.
Polyunsaturated fats include omega 3, 6 and 9 which are vital fats to help maintain health.
The omega name is a result of the amount of carbons bound together before a double bond. So, if there are three carbons bound before a double bond, it will be Omega 3. The ‘carbon ends’ are often referred to as methyl ends.
What is the role of vitamin A, B1, b2, and B3
A - maintain epithelial health, bone health, pigment in eyes
** B1 ** - (thiamine), co enzyme for metabolism of carbohydrates, sythesis of acetylcholine
** B2 ** - riboflavin, coenzyme in carbohydrates and protein in eyes and skin cells and GI tract and blood
** B3 ** - pyridoxine co enzyme in amino acids and fat metabolism , assist in antibody production
What is the role of vitamin B6, B12, C and D
B6 - pyridoxine - co enzyme in amino acid and fat metabolism, assist in antibody production
B12 - cyano-cobalamin - co enzyme for > formation of red blood cells, enzyme acids and neuro transmitter choline
C - formation of connective tissue , promotes protein metabolism/ wound healing
D - absorption of calcium and phosphate from the GI tract
What the role of vitamin E and K
E - necessary for nucleotides for cell formation, promoting wound healing and neural function
K - co enzyme necessary for producing clotting factors
What is the mineral sodium, potassium and calcium for?
sodium main component of Extracellular fluid, needed for action potential for nerves and muscles, part of Ph buffer systems
** potassium ** main ion for intracellular fluid, needed for action potential
** calcium ** needed for growth of bones and teeth, blood clotting, muscle contraction and production of neurotransmitters
What is the role of these minerals - magnesium, iron and copper?
** magnesium ** normal muscle and nerve function
** iron ** major component of haemoglobin, needed for intracellular respiration
** copper ** works with iron for haemoglobin formation, co enzyme for melanin formation
What is the role of the minerals - chlorine, phosphorous and iodine
** chlorine ** main component of intracellular and Extracellular fluids, necessary acid-base balance, formation of hydrochloric acid in the stomach
** phosphorus ** formation of bone and teeth, apart of Ph buffer system, nerve conductive and component of nucleotides and ATP
** iodine ** main component of throid hormones
What are enzymes?
** Enzymes are protein based structures that are designed to speed up biochemical reaction **
When an enzyme binds to a substrate it becomes a product which is the final outcome of whatever the enzyme is trying to encourage. The binding site is often referred to as the active site. Enzymes can either act alone or there can be a group of enzymes working together.
Enzymes will either breakdown a substrate into smaller elements, or it can create a bigger structure.
What is the ideal temperature enzymes work at?
36.5 degrees
What are the different ways enzymes can bind and how do they work? L___ K____ me___
** the lock and key approach **
the idea being that an enzyme and substrate can be structurally similar that they easily bind together like two jigsaw pieces. When they bind together, a reaction occurs and the products of the substrate are made:
How do enzymes bind to a substrate I___ F___
** induced fit **
this type of bonding is similar to the lock and key except the enzyme’s structure has slight differences to the structure of it’s substrate. However, when the enzyme binds to the enzyme, the enzyme can mould around the substrate to bind to the enzyme.
What are co-enzymes
Sometimes enzymes need help with a reaction or binding to a substrate, this is when co-factors and co enzymes come in
Co-enzymes and co-factors can activate an inactive enzyme or/and support the binding of an enzyme to a substrate.
Usually non-organic elements such as iron or organic such as heme
Help sleep up chemical reaction, e.g ATP speeds up muscle contraction
How are medication enzyme inhibitors?
A lot of medication are designed to be enzyme inhibitors, which means they are designed to slow down the reactions of enzymes. It can do this by binding to the enzyme’s active site where the substrate would normally bind which blocks the reaction, or it can slow down the catalysis phase which is the process of how an enzyme speeds up a reaction. For example, antibiotics such as penicillin block enzymes in bacteria that maintain the bacteria’s cell wall, meaning that the bacteria will burst due to a damaged cell wall.
Label this digestive system
A - mouth
B - tongue
C - esophagus
D - liver
E - gallbladder
F- duodenum (small intestine)
G - jejunum (small intestine)
H - Illeum (small intestine)
I - anus
J - parotid gland (salivary glads)
K - sublingual gland (salivary glands)
L - submandibular gland (salivary glands)
M - pharynx
N - stomach
O - spleen
P - pancreas
Q - Transverse colon (large intestine)
R - ascending cool (large intestine
S - descending colon
T - caecum
U - sigmoid colon
V - appendix
W - rectum
X - anal cavity
What is the brief description of the mouth stages of digestion
- mechanical digestion includes chewing and swallowing
- chemical digestion of carbohydrates and fats
What does the autonomic nervous system help control in digestion?
The autonomic nervous system helps to control aspects of the gastrointestinal system such as peristalsis and the release of mucus and enzymes
Look at this mouth anatomy
What are the four layers of the oesophagus?
- The muscosa - the inner most layer that is in contact with the food, mucus barrier to lubricate the lining
- The submucosa - connective tissue layer that provides support and is where the nerves and blood vessels are found
- The muscularis where the two muscle layer are found
- The Serosa - the outmost layer that is in contact to the abdominal cavity, forms part of the visceral peritoneal membrane
What are the four distinctive anatomical parts to the stomach
- The Cardia - the opening between the oesophagus and the stomach, where food enters the stomach.
- The Fundus - located at the top of the stomach and is located horizontally next to the cardia.
- The Corpus - also called the gastric body, it is the largest part of the stomach.
- The Pylorus - the opening from the stomach to the duodenum.
What is the pylorus?
It’s where the stomach and the duodenum meet, it is split into two areas > the muscle there is called the pyloric sphincter which is a circular layer of smooth muscle.
- The pyloric antrum - connected to the stomach
- The pyloric canal - connected the duodenum
Label this
A - stomach
B - gallbladder
C - common bile duct
D - duodenum
E - pancreas
What is the illeum?
The ileum is the longest part of the small intestine, and it is where the majority of nutrients are absorbed. The lining of the jejunum and ileum which we will discuss later are lined with structures called circular folds. On the circular folds are microscopic finger like structures called villi
What are the causes of vomiting/ diarrhoea
Physiological causes : Constipation, Gastroenteritis, Outlet obstruction, Bowel obstruction, Raised ICP, Hepatomegaly, Cough, Oral Thrush, Motion sickness.
Metabolic causes– Uremia, Endocrine imbalance, Electrolyte imbalance – hyponatremia, hypercalcemia.
Treatment related – Chemo, Radiotherapy, Medications.
Emotional/Psychological – Anticipatory, loss of personhood, role change, anxiety, fatigue, grief, overwhelming sensory perception such as offensive smells.
Main causes for diarrhoea?
Secretory diarrhoea - when there is disruption to the absorption of ions that would usually encourage water to cross over too - such as sodium. This can be a result of inflammation caused by bacterial or viral infections or medication such as laxatives.
Infectious/Inflammatory diarrhoea - caused by bacterial, viral or parasitic infections that causes inflammation across the whole intestines. Inflammation in the small intestines means that more water is secreted, and inflammation in the large intestines means that less water is being reabsorbed to form faeces.
**Osmotic **- caused by either over-consumption of electrolytes and salts or it can be caused by conditions that generate a high osmolality within the intestines which causes water to secrete into the bowel. Laxatives such as lactulose can cause this as can underlying conditions such as Coeliac disease and lactose intolerance.
