digestive system

Question 1

functions

Answer 1

ingestion
secretion
mechanical processing
digestion
absorption
defeacation

Question 2

ingestion

Answer 2

digestive tract via the oral cavity
An active process involving conscious choice and decision-making

Question 3

secretion

Answer 3

non-specific defence against the corrosive effects of digestive acids and enzymes

water, acids, enzymes, buffers, and salts from the epithelium of the digestive tract and glandular organs into the digestive tract

Question 4

mechanical processing

Answer 4

Physical breakdown of food into smaller particles that makes materials easier to propel along the digestive tract
Mixes the food with secretions and increases the surface area of the food,

Question 5

digestion

Answer 5

Chemical breakdown of food into small organic fragments suitable for absorption by the digestive epithelium

Question 6

absorption

Answer 6

The movement of organic molecules, electrolytes (inorganic ions), vitamins, and water across the digestive epithelium, into the interstitial fluid

Question 7

defacation

Answer 7

Elimination of wastes, indigestible substances, bacteria, dead cells from the body.

Question 8

4 layers of digestive tract

Answer 8

muscosa

submucosa

muscularis

serosa

Question 9

mucosa

Answer 9

inner lining where The locations where absorption occurs,

moistened by glandular secretions

Question 10

submucosa

Answer 10

Dense, irregular connective tissue beneath the mucosa
Has numerous blood vessels and lymphatic vessels

Question 11

muscularis

Answer 11

Dominated by smooth muscle cells
The inner circular layer is essential for agitation and in the formation of valves
The outer longitudinal layers of muscle is essential for mechanical processing

Question 12

serosa

Answer 12

Covers the muscularis externa along most portions of the digestive tract

Question 13

oral cavity

Answer 13

lubrication by mixing with mucus and saliva
mechanical digestion through the actions of the teeth, tongue and palatal surfaces

-initiation of carbohydrate digestion by salivary amylase

• initiation of lipid digestion by lingual lipase

Question 14

salivary glands

Answer 14

lysozyme: kills bacteria

• enzymes: salivary amylase and lingual lipase

Saliva:

• lubricates the food and helps combine materials in the mouth with the digestive enzymes

Question 15

pharynx

Answer 15

passageway for solid food, liquid and air. Swallowing is the process that allows for a substance to pass from the mouth

Question 16

oseophagus

Answer 16

hollow muscular tube, posterior to the trachea, that conveys solid food and liquids to the stomach.

peristalsis then into the stomach through an open lower oesophageal sphincter

Question 17

liver

Answer 17

Metabolic regulation:

• modifies and stores excess glucose, amino acids, and fatty acids therefore stabilising blood glucose levels

Haematological regulation – synthesis and release of the plasma proteins, including albumin, transport proteins, clotting proteins, and complement proteins.

Bile production – bile salts break lipid droplets apart in a process called emulsification, which dramatically increases the surface area

Question 18

gall bladder

Answer 18

stores and concentrates bile prior to its excretion into the small intestine

Question 19

stomach

Answer 19

Parietal cells:

• secrete intrinsic factor – required for the absorption of vitamin B12 in the small intestine

secrete hydrochloric acid

Chief cells:

• secrete pepsinogen – becomes pepsin when activated by HCl, digests protein.

Question 20

pancreas

Answer 20

ecause it secretes the hormones, insulin and glucagon into the bloodstream.

Exocrine – because it secretes pancreatic juice into the duodenum. Pancreatic juice contains:

• an alkaline solution containing bicarbonate

Question 21

small intestine

Answer 21

Duodenum – first and shortest segment of small intestine, receives chyme from the stomach and digestive secretions from the pancreas and liver.

Jejunum – middle segment of small intestine, is the location where the most chemical digestion and nutrient absorption occurs.

illeum- final segment of small intestine that ends at the ileocecal valve which is a sphincter that controls the flow of material from the ileum into the cecum of the large intestine.

Question 22

teeth

Answer 22

mastification

tearing apart your food

then the tongue will squash

Question 23

mechanical digestion

Answer 23

mastification
mixing and churning
segmentation
peristalis

increases surface area of food

Question 24

peristalis

Answer 24

Contraction of circular muscles
behind bolus
2. Contraction of longitudinal
muscles ahead of bolus
3. Contraction of circular muscle
layer forces bolus forward
contraction
contraction
contraction
longitudinal muscle
circular muscle

Question 25

carbohydrates

Answer 25

Monosaccharides are the smallest carbohydrate. They can be absorbed and are water soluble

Disaccharides are two monosaccharides joined together. They are water soluble

Complex carbohydrates do not dissolve in water or other body fluids

Question 26

function of protein

Answer 26

Structural proteins create a framework for the body
Contractile proteins bring about muscle contraction
Transport proteins transport substances in the blood
Form hormones for coordination and control of body processes
Provides pH buffering to prevent dangerous pH changes of body fluids
Control metabolic reactions.
Provide defense against pathogens e.g., antibodies

Question 27

primary amino acid

Answer 27

the sequence of amino acids along the length of a single polypeptide. Peptide bonds are responsible for the primary structure of proteins.

Question 28

secondary amino acids

Answer 28

the shape that results from the presence of hydrogen bonds between atoms at different parts of the polypeptide chain. Hydrogen bonding may create either an alpha helix or beta sheets.

Question 29

tertiary amino acids

Answer 29

the complex coiling and folding that gives a protein its final 3D shape. Tertiary structure results primarily from hydrophobic, hydrophilic and disulphide bonds.

Question 30

quarternary structure

Answer 30

he interaction between individual polypeptide chains to forma a protein complex.

Question 31

lipids

Answer 31

Structural component e.g. plasma membrane
Energy source – provide twice as much energy as carbohydrates do, gram for gram but when in excess stores in fat deposits
Chemical messenger – to corrinate cellular activites
Insulation – fat deposits slow heat loss to the environment
Protection – fat deposits around delicate organs such as the kidneys provides a cushion that protects against bumps or jolts.

Question 32

age to digestion

Answer 32

Epithelial stem cell division rate decreases – this results in the epithelium being more susceptible to damage by abrasion, acid and enzymes and can lead to peptic ulcers as tissue repair is less efficient with aging.
Smooth muscle tone decreases – this results in a decrease in general motility and weaker peristaltic contractions leading to constipation. Straining to eliminate compacted faecal matter stresses less resilient blood vessels causing haemorrhoids. Weakening of muscular sphincters can lead to oesophageal reflux and heartburn.
Cumulative damage from toxins (e.g. alcohol) can lead to a gradual loss of teeth due to dental cavities, liver cirrhosis, and cancer.