GI Flashcards
(58 cards)
define autotrophs
Autotrophs are able to make their own food- All plants and some prokaryotes are autotrophic- photosynthesis
define heterotrophs and the 3 types
“Heterotrophs obtain organic (carbon-based) food which was originally synthesised by plants (Animals, Fungi, Some protists and prokaryotes)
-Holozoic nutrition:
- Solid or liquid food/organic material is taken in, broken down and absorbed
- Most animals
- Complex food taken into specialist digestive system.
-Saprotrophic nutrition
- live and feed off dead or decayed organic matter
- secrete enzymes which digest the food then absorb the soluble products- fungi
-Parasitic nutrition:
- Parasites
- Live on or in a host organism from which they obtain their food”
what are the 6 processes of digestion with brief descriptions
“Ingestion – taking food into GI
Propulsion – moves food through alimentary canal
- swallowing,
- peristalsis
Mechanical breakdown
- mastication,
- churning,
- segmentation
- Increases surface area
Chemical digestion
- Enzyme secreted into lumen
Absorption
- Uptake of digested products
Egestion:
- Elimination of indigestible material from the body”
what are the sources and function of protein, carbs and lipids in the diet
“Proteins –
source: Milk, eggs, meat, fish – complete Legumes, nuts, cereals – incomplete (low in one or more essential amino acids)
Function: Structural role- skin, hair, teeth, bone, muscle.
metabolic roles, enzymes, hormones, transport proteins
Lipids -
sources: Triglycerides animal products (saturated) Unsaturated in seeds , nuts olive oil, Cholesterol – egg, yolk, meats, dairy. ,
Function: Fatty adipose tissue (energy store), Insulation, Protection, phospholipids – cell membranes, Cholesterols – cell membranes, hormones
Carbohydrates
Sources: Mainly plants from plants, Simple sugars – from fruits, sugar cane, sugar beet, honey and milk, Complex carb – grains and veges
Function: energy source - glucose
Red blood cells and neurones.
The glycocarlyx”
name the vitamins needed, their sources and function
“A- Retinol- Liver, milk, egg yolk, carotene- Formation of rhodopsin
B1- Thiamine- Cereal, brown rice, nuts and beans- TPP – coenzyme
B2- Riboflavin- Milk, eggs, yeast, liver, cereal- FAD – coenzyme in respiration
B3- Niacin- Nuts, meat and grain- Co-enzymes NAD, NADP
B5- Pantothenic acid- Most foods- Component of co-enzyme A
Vitamin C- Ascorbic acid Fresh fruit and vegetables- Electron carrier, collagen formation, utilisation of iron, stimulates immune system
D- Cholecalciferol- Synthesized in the skin, dairy products, oily fish, egg yolk- Calcium metabolism
E- Tocopherol- Vegetable oils, nuts, green leafy vegetables, and fortified cereals- Antioxidant, free radical scavenger, membrane integrity
K- Phylloquinone menaquinone- Green leafy vegetables- Blood clotting
Osteocalcin synthesis”
factors affecting energy requirements in animals
“gender
- females need fewer calories than male animals because males generally have a higher metabolic rate
- Studies shows that neutered animals are twice as likely to become obese compared to intact dogs.
growing animals:
requires higher concentrations of protein (amino acids), calcium, phosphates, and energy in the diet to support basic physiological processes in addition to bone, connective tissue, muscle, and coat formation
pregnancy and lactation:
rely on forage and are only given concentrates during the last stages of pregnancy and early lactation.
Dairy cows need high levels of ME to sustain milk yields and so are fed concentrates to supplement forage
Small animals also have increased energy demands during late pregnancy and lactation, although cats show an increased intake from conception
Water is essential for all animals during lactation – thing that is often forgotten
Folic acid is especially important in the early stages as it’s crucial for development of the neural tube.
working animals:
Racehorses require a diet that is high in energy to fuel the levels of performance- require water
- supply of fast- and slow-release energy
- diets high in fat, protein, fibre and starch are appropriate for high-performance racehorses and they can obtain most of these nutritional elements from a combination of forage”
what are the 4 layers of the GIT and describe
“The mucosa
- Epithelial layer, protective, cells have a short lifespan (2/3 days), secretions, absorption
- Connective tissue layer, blood vessels, nerves, lymph vessels
- Muscularis mucosae, thin smooth muscle layer
The Submucosa
- Connective tissue, blood vessels and nerves
Musculariz
- 2 layers of smooth muscle, inner circular and outer longitudinal
- Myenteric plexus: a network of neurons between the 2 layers
Serosa
- A thin layer of connective tissue
- Covered by the peritoneum (epithelial cells)”
describe the oesophagus
”- Runs from pharynx to stomach. Role is to convey food to the stomach
- Cervical, thoracic and abdominal sections
- Muscularis – striated initially and then becomes smooth. Muscles needed for PERISTALSIS
- Mucosa – Stratified squamous epithelia for extra protection
- Sphincters at upper opening of oesophagus and at junction with stomach
- In many species, it enters stomach at sharp angle, aids function of lower sphincter and reduces vomiting (eg horses).”
describe peristalsis and the muscles involved
”- The process by which food is moved along the oesophagus to the stomach
- During peristalsis, the circular and longitudinal muscles in the oesophagus contract and relax in a wave-like pattern to move food through the digestive tract:
- Circular muscles: These muscles squeeze and expand in a coordinated way to push food through the oesophagus.
- Longitudinal muscles: These muscles shorten the oesophagus and propel food forward”
describe the stomach and the types
”- Chemical and mechanical digestion (to produce chyme)
- Stores food and to transfer stomach content to SI at a rate to ensure maximum digestive efficiency. (eg. Carnivores)
- Variation between species
- Monogastric
- Ruminants”
describe the mono gastric stomach
”- Located behind diaphragm
- Sphincter prevents reflux
- 4 regions
- Cardia, small except in the pig where food is stored
- Fundus, stores food
- Corpus, mixing with gastric juice
- Pylorus, mixing, pyloric sphincter
- gastric glands on inner lining of stomach”
whats the role of gastric glands
”- Mucus production for protection from digestive enzymes/acid
- Gastric juice is secreted by gastric glands
- Gastric juice contains
- HCl from parietal cells
- pepsin from chief cells
- contain endocrine cells, -produce gastrin, a hormone that stimulates the stomach to release acid”
describe the role of pepsin and HCL
”- Pepsin is secreted from chief cells as the inactive enzyme precursor pepsinogen
- This prevents autodigestion
- Activated by HCl and pepsin itself in the lumen of the stomach
- Pepsin breaks down proteins into peptides and amino acids. It works with other enzymes, such as trypsin and chymotrypsin, to digest food
- HCL Secreted from parietal cells in the gastric gland
- Activates pepsinogen
- Provides optimum pH for pepsin activity
- causes pepsinogen to be cleaved into the active enzyme pepsin”
what are the 3 ways that gastric secretion is controlled
“1. Reflex due to sight and smell of food- The nerve impulses affect the epithelial cells directly and cause a release of gastrin
2. Expansion of the stomach by the presence of food causes smooth muscle to contract. Secretion of gastrin into the bloodstream from special cells in the pyloric region of the stomach. The hormone stimulates the secretion of pepsin and HCl. It also stimulates muscular movement of the stomach
3. Control by peptides
- Peptide production
- G cell secrete more gastrin
- Parietal cells increases HCl production”
what are the 4 stoamchs of ruminants and their function
“The Rumen: The rumen stores and ferments food. Salivary enzymes aid digestion, while muscular contractions churn the contents. It houses bacteria that produce cellulase, breaking down cellulose into beta-glucose, which is further fermented into volatile fatty acids (ethanoic, propionic, and butyric acids). These acids are absorbed through the rumen wall.
Reticulum: balls of cud formed and then regurgitated
The Omasum: Once food is liquid enough, it enters the omasum, a chamber with tissue folds that absorb water and concentrate the contents.
The Abomasum: The abomasum, or “true stomach,” produces hydrochloric acid and enzymes like pepsin, breaking down food before it enters the intestines.”
describe the tongue and its function in the oral cavity
”- highly muscular organ
- surface covered in papillae,
- function of tongue- Prehension, Forming bolas, Pushing bolas back to oropharynx, taste, Grooming, Speech articulation
- function varies between species (taste buds, grooming, manipulate food)”
describe the role of salvilary glands in digestion
“Salivary Glands:
Chemical digestion:
- Liquid – mixing food / formation of bolas
- Digestion
- Enzymes
- α-amylase - Amylase starts the digestion of starch (mostly)
- lysozyme - Lysozyme acts to cause lysis in bacteria.”
describe mastications role in digestion
“chewing- mechanical digestion:
- Involves the actions of jaw, teeth, tongue and cheeks
Muscles of mastication – all of these raise the jaw”
describe how the size of the temporalis and masseter differ in different species
”- Temporalis is larger in carnivores
- Carnivores and omnivores have mainly a vertical action for a cutting effect.
- Carnivores able to open mouth wide
- the jaw joint is on the smae plane as the teeth so tighter connection
- Masseter is larger in herbivores
- Herbivores also move jaw laterally which helps to grind food”
what is the function of cementum
the calcified or mineralized tissue layer covering the root of the tooth which sits inside the gum socket
what is the function of dentine
hard dense bony tissue forming the bulk of a tooth, beneath the enamel
what is the function of enamel
Tooth enamel is the hard, shiny, white outer layer of your teeth that covers the underlying tissues. The hardest substance in the body, stronger than bone – and is made up almost entirely of minerals.
what is the function of tooth roots and the pulp cavity
“Tooth Roots: Attach to the alveolar bone (mandible) via the periodontal ligament
Pulp Cavity: The area in between the tooth root that contains blood vessels and nerve endings”
what are the muscles involved in mastication nd where are they.
”- Temporalis: Top of head (O) → Coronoid pr of mandible
- Masseter: Zygomatic arch (O) → Ramus of mandible
- Pterygoid: sphenoid bone (O) → condylar pr of mandible”
