Digestive System Flashcards
Stages of digestion
Chewing Mixing with acid Digestive juices and enzymes Breaks down into constituent parts proteins, carbs, acid and fats
The constitute parts are absorbed at what
Different level of digestive tract
The digestive system is a collection of organs and tracts whose solo function is to do what
Break down solid and liquid food into usable basic chemicals required by the body
What do I need to know about nutrition?
What do I need to know about nutrition?
The principle nutrients of the body are carbohydrates, fats and proteins. During digestion, carbohydrates are converted to glucose, fats to fatty acids and proteins to amino acids. These molecules then enter the cells and react chemically with oxygen, under the influence of enzymes , to release energy.
Amino acids
Amino acids
These must be supplied in food:
Arginine
Lysine
Tryptophan
Histidine
Methionine
Leucine
Phenylalanine
Isoleucine
Minerals
Minerals
A number of mineral salts play an important role in the process of metabolism. Some are present in relatively large amounts, while others are only needed in minute quantities.
All are derived from food:
Calcium
Magnesium
Fluorine
Phosphorus
Iron
Potassium
Iodine
Sodium
Vitamins
Vitamins
Vitamins or accessory food factors are organic compounds that are needed in small quantities for metabolism .
These are derived from food:
Fat soluble vitamins:
- A - liver, dairy produce, eggs and fish
- D - fish, margarine, butter and eggs
- E - wheatgerm, vegetable oil, dairy products
- K - present in many foods
Water soluble vitamins:
- B 1 - cereals, flour, peas and beans
- B 2 - meat, milk and flour
- B 3 - meat, liver and flour
- B 6 - present in many foods
- B 12 - liver meat and animal products
- Folic acid - present in many foods
- Pantothenic acid - liver, meat, eggs, milk
- C - fresh fruit and vegetables
name body’s essential nutrients
minerals
vitamins
Amino acids
How is food intake regulated?
How is food intake regulated?
The control mechanisms to regulate food intake lie within the hypothalamus. There are two clusters of nerve cells, one in the lateral nuclei known as the feeding (hunger) centre and one in the medial nuclei, known as the satiety centre.
The feeding centre is constantly active but it is overridden when impulses are stimulated by the satiety centre.
There are five basic elements to the digestive process:
- Ingestion - taking food into the body
- Movement - passage of food along the digestive tract
- Digestion - breakdown of food by chemical and mechanical processes
- Absorption - passage of digested food from the digestive tract into the cardiovascular or lymphatic systems
- Defecation - elimination of indigestible substances
There are five basic elements to the digestive process name them
There are five basic elements to the digestive process:
- Ingestion - taking food into the body
- Movement - passage of food along the digestive tract
- Digestion - breakdown of food by chemical and mechanical processes
- Absorption - passage of digested food from the digestive tract into the cardiovascular or lymphatic systems
- Defecation - elimination of indigestible substances
three words describe process of eating
Bolus
peristalsis
chyme
alimentary tract and function Mouth
Mouth
This is also known as the buccal cavity.
It is lined with a mucous membrane thinner than the skin. The boundaries of the mouth are the hard palate superior, the maxilla laterally and the soft palate or uvula inferior. The main muscles forming the walls of the mouth are the masseter, buccinator and obicularis oris muscles.
There are three pairs of salivary glands that discharge into the mouth:
Parotid glands - at the level of the cheek
Submandibular glands - at the level of the mandible
Sublingual glands - below and to the midline of the tongue
It is the parotid glands that are generally affected in the viral condition mumps.
The tongue is composed almost entirely of voluntary muscle. Its functions are those of mastication, swallowing, speech and taste. The under-surface and anterior part of the tongue are covered by a thin mucous membrane that forms a central fold, which attaches to the floor of the mouth and is called the frenulum.
Difficulty in swallowing is known as dysphagia.
alimentary tract and function Pharynx
Pharynx
This is an expandable muscular tube lying posterior and inferior to the mouth and is divided into the oropharynx and laryngopharynx.
Within the oropharynx lie the palatine tonsils.
The nerve supply of the pharynx involves some of the cranial nerves
alimentary tract and function Oesophagus
Oesophagus
A collapsible muscular tube extending from the pharynx to the cardiac sphincter protecting the stomach. It leaves the thorax by piercing the diaphragm to enter the abdomen.
The cardiac sphincter prevents regurgitation of stomach contents into the oesophagus
alimentary tract and function Stomach
Stomach
This lies within the epigastric, umbilical and left hypochondriac regions of the abdominal cavity. To the left of the cardiac sphincter is a pouch shaped upper part of the stomach called the fundus. Below this is the body of the stomach ending at the pyloric sphincter .
The stomach is lined with a thick mucous membrane that has a smooth soft velvety surface when distended but recoils to form lots of irregular folds (rugae) when empty.
Within the lining of the pyloric vesicles are glands responsible for the secretion of the “intrinsic factor”, essential for the absorption of vitamin B12.
alimentary tract and function Duodenum
Duodenum
The duodenum is approximately 25-30cm long and lies in a C shape around the head of the pancreas.
It is fixed to the abdominal wall by a loop of peritoneum.
The point of entry for the bile and pancreatic duct s is known as the ampulla of vater
alimentary tract and function Jejunum and ileum
Jejunum and ileum
The jejunum forms two fifths of the small intestines and the ileum makes up the remaining three fifths.
The mucous membrane of the small intestine is arranged in permanent folds called plicae cartularies. They effectively increase the surface area for secretion and absorption. Projections of this lining extend in outward microscopic fingers called villi. Between each villus lie tubular glands (crypts of lieberkuhn). Lymphatic tissue is scattered throughout the whole of the small intestine in collected masses (peyer’s patches). Blood is suppled via the superior mesenteric artery .
Parasympathetic impulses increase peristaltic movement and secretion of intestinal glands. These impulses also cause the ileocaecal sphincter to relax.
The functions of the small intestines are to complete digestion of food (through secretion), to absorb the end products of digestion (through villi) and to move the chyme towards the ileocaecal sphincter (through peristalsis).
Poisons fall into the 4 main groups
Burning or corrosive poisons
Non-burning poisons
Industrial poisons and pesticides
Irritant poisons
alimentary tract and function Peritoneum
Peritoneum
The peritoneum is a serous membrane and like other important serous membranes of the body has two layers, the outer parietal layer and the inner visceral layer.
Peritoneal ligaments
The liver, uterus and other organs are partly maintained in position by means of double folds of peritoneum which form suspensory ligaments.
Omenta
These are folds of peritoneum connected to the stomach. The great omentum hangs from the lower border of the stomach like an apron in front of the small intestine.
Mesentery
This is a fold of peritoneum that encloses the small intestine and anchors it to the posterior abdominal wall. The attachment to the abdominal wall is relatively short, whereas the intestinal part is many feet long, so the mesentery can be described as a fan-shaped structure.
Functions of the peritoneum include:
Allowing movement of organs without friction
Partial/complete covering of organs
Forming ligaments and mesenteries for anchorage
Absorbing fluid in large quantities
Acting as a body store - omenta and mesentery contain fat
Slowing the spread of infection - omentum has the ability to move and will wrap around inflamed organs and tracts
alimentary tract and function Large intestine
Large intestine
- Approximately 1.5m in length the large intestine is made up of:
- Caecum and veriform appendix
- Ascending colon
- Transverse colon
- Descending colon
- Pelvic or sigmoid colon
- Rectum and anal canal
Blood is supplied via both the superior and inferior mesenteric arteries . The veins of the anus form dilated vessels within the anal ring called the haemorrhoidal plexus.
The functions of the large intestine are the absorption of water and electrolytes from chyme passing through it and the expulsion of waste material from the body.
The large intestine contains a multitude of bacteria. These synthesize vitamins B and K, which are then absorbed into the blood by the mucosa
alimentary tract and function Ileum
Jejunum and ileum
The jejunum forms two fifths of the small intestines and the ileum makes up the remaining three fifths.
The mucous membrane of the small intestine is arranged in permanent folds called plicae cartularies. They effectively increase the surface area for secretion and absorption. Projections of this lining extend in outward microscopic fingers called villi. Between each villus lie tubular glands (crypts of lieberkuhn). Lymphatic tissue is scattered throughout the whole of the small intestine in collected masses (peyer’s patches). Blood is suppled via the superior mesenteric artery .
Parasympathetic impulses increase peristaltic movement and secretion of intestinal glands. These impulses also cause the ileocaecal sphincter to relax.
The functions of the small intestines are to complete digestion of food (through secretion), to absorb the end products of digestion (through villi) and to move the chyme towards the ileocaecal sphincter (through peristalsis).
What is diabetes mellitus?
What is diabetes mellitus?
Diabetes mellitus is a chronic disorder that affects approximately 200 million people world-wide. It happens when the body is unable to metabolise carbohydrate, resulting in a raised blood sugar level.
Hyperglycaemia signs symptoms
Hyperglycaemia
This is high blood sugar.
The onset of hyperglycaemia is gradual and may take several days. There are inadequate amounts of insulin for the amount of sugar, so the body’s glucose level becomes too high and body fat reserves are broken down; resulting in the production of organic acids or ketones .
The patient will show signs of restlessness but will eventually become lethargic and their level of consciousness will deteriorate into total unconsciousness and if left untreated, death. Quick medical intervention is very important.
Signs and symptoms include:
- Gradual onset, hours or maybe days
- Dry flushed skin
- Deep sighing respirations
- Pulse of 100+
- Fruity breath smell (acetone)
- Fever and thirst
- Nausea
- Lethargy
- Drowsiness
- Vomiting
