Digestive System

Question 1

why are animals heterotrophic

Answer 1

they obtain the nutrients they need to survive from plants or other animals, these nutrients are processed by digestive system

Question 2

name the nutrient groups

Answer 2

proteins, lipids, carbs, vitamins, minerals, fibre, water

Question 3

function of proteins

Answer 3

necessary for growth and maintenance of all body cells and tissues. enzymes are proteins as some are hormones and proteins also form some transport molecules (haemoglobin) also a source of energy

Question 4

functions of carbohydrates

Answer 4

supply energy to cells

Question 5

functions of lipids

Answer 5

fats supply and store energy and insulate, support and cushion organs. are also involved with absorption of fat-soluble vitamins

Question 6

functions of vitamins

Answer 6

promote specific chemical reactions within cells

Question 7

functions of minerals

Answer 7

used for growth and maintenance of bones and teeth, are also involved with osmoregulation, nerve transmission, muscle contraction, transport systems and other functions

Question 8

functions of fibre

Answer 8

adequate dietary fibre is needed to increase bulk and water in the intestinal contents to promote and regulate normal bowel function ad transit times

Question 9

functions of water

Answer 9

water make sup 50-70% of body weight and provides a medium for chemical reactions, also transports chemicals, regulates temperature and removes waste products

Question 10

what are the two digestive processes

Answer 10

mechanical -
chemical -

Question 11

what is the process of mono gastric digestion

Answer 11

-food enters out and is mechanically broken down by teeth and tongue
-saliva is added which starts the chemically digest the food
- food is swallowed and moves down oesophagus to the stomach
- in the stomach hydrochloric acid and enzymes are added which break down the food even further to form chyme
- when it enters the duodenum, bile emulsifies fats and neutralises stomach acid and more enzymes are added
- in the jejunum and ileum nutrients are absorbed and taken to cells for use or storage
- in the large intestine, water and some water soluble vitamins are absorbed through the villi
- the villi provides a larger s.a for absorption and contain a network of capillaries to allow for the effect diffusion of molecules
- waste material is stored in the rectum until it leaves the body via the anus

Question 12

where is bile made and stored

Answer 12

made - liver
stored - gall bladder

Question 13

how do hindgut fermenters digest their food

Answer 13

they digest the majority of their food in their cecum and at the start of the large intestine where there are large numbers of microbes to ferment the food

Question 14

why do some herbivores need to adapt their digestive system to their diet

Answer 14

they eat mostly high fibre plant material which is difficult to digest

Question 15

describe bird digestion

Answer 15

they do not chew so instead they use their tongue to move food to the back of their mouth where it is swallowed and food moves from the oesophagus to the crop before passing to the proventriculus where digestive enzymes and hydrochloric acid are added then food moves to the ventriculus where it is mechanically digested where the small and large intestines join, there are 2 ceca where some water is reabsorbed and the food is fermented. the cloaca at the end of the digestive system mixes digestive and urinary waste and expels them as one substance

Question 16

what does a ruminants foregut fermenters stomach consist of

Answer 16

rumen, omasum, reticulum, abomasum

Question 17

process of foregut fermenters

Answer 17

1. rumen - anaerobic environment where microbes secrete enzymes, saliva helps to ensure there is a suitable environment for the micro flora to survive.
   (retro peristalsis allows food to be brought back up to allow it to be mechanically broken downwind swallowed for more digestion
2. reticulum - aids the rumen and helps form the undigested feed into the cud, it filters the food in the rumen allowing only parts which are sufficiently broken down to move to omasum
3. omasum - some water and salts are absorbed then the remaining matter is passed to abomasum
4. abomasum - the true stomach, digestive enzymes and acid are added

Question 18

what does a herbivores oral cavity consist of

Answer 18

diastema, dental pad, incisors, premolars, molars

Question 19

what does a carnivores oral cavity consist of

Answer 19

carnassial teeth, incisors, canines, premolars, molars

Question 20

what does a birds oral cavity consist of

Answer 20

upper and lower mandible

Question 21

explain adaptations of a herbivores dentition

Answer 21

instead of upper incisors they have dental pad, they grasp plants with their tongue and use lower incisors against dental pad to rip. no canine teeth and thoroughly grind food and mix it with large amounts of saliva. molars continually grow and are worn down by silica in plants

Question 22

explain adaptations of a carnivores dentition

Answer 22

canines enable them to rip meat which are paired with carnassial teeth allowing them to shear meat, more efficient than tearing. cannot digest cellulose due to lack of cellulase.

Question 23

explain adaptations of a birds dentition

Answer 23

beaks are made of bone, keratin and blood vessels. they continually grow and are worn down by grooming, feeding, climbing and rubbing. shape of beak is adapted to type of food they eat. no teeth as they do not chew

Question 24

why is glucose needed

Answer 24

cells need it for respiration as its important that conc of glucose in blood is maintained at constant level

Question 25

how is blood glucose regulated

Answer 25

by pancreas in homeostatic process, pancreas detects blood glucose conc then releases hormones which alter the amount of glucose in the blood

Question 26

process of high blood sugar

Answer 26

-pancreas detects the rise in blood glucose conc
-pancreas increases secretion of insulin and decreases secretion of glucagon
- insulin is increased by beta cells in pancreas
- insulin causes muscle and liver cells to remove glucose from blood and store as glycogen stored in tissue cells causing blood sugar to lower

Question 27

process of low blood sugar

Answer 27

• pancreas detects fall in blood glucose conc
• pancreas decreases secretion of insulin and increases secretion of glucagon
• glucagon is released by alpha cells in pancreas
• glucagon causes liver cells to convert glycogen to glucose and release it into the blood causing blood sugar to raise

Question 28

what can digestive disorders lead to

Answer 28

dehydration, acid base and electrolyte imbalances and malnutrition

Question 29

describe how ingestion of foreign bodies cause issues

Answer 29

can cause obstruction in the digestive system, can slow the digestive process and lead to regurgitation of food or block the digestive system completely
some foreign bodies like nails or tools can puncture the digestive system leading to infection or death

treatment involves surgery for removal

Question 30

causes and treatments of sickness and diarrhoea

Answer 30

caused - unsuitable amount of food, contaminated food, unsuitable food types, stress, pathogens

treatments - vary on cause

Question 31

what are the types of ruminant bloat, describe them

Answer 31

frothy bloat - caused by foam in the rumen trapping the gas, most common in animals fed a high protein diet, low roughage diet

free gas bloat - caused by obstruction in the oesophagus

needs surgical procedures to relieve the bloat

Question 32

what’s mechanical digestion

Answer 32

where large pieces of food are ingested and physically broke down into smaller pieces

Question 33

whats chemical digestion

Answer 33

larger molecules of food are broken down into smaller molecules by enzymes, acid and bile