LO3: Digestive System

Question 1

Describe the function of small & large intestine, anus, rectum, liver, bile duct and pancreas

Answer 1

• Small intestine - Absorbs most of nutrients from food we consume to absorb into blood
• Large intestine - Absorbs water from chyme and empties waste to be stored as faeces into anus.
• Anus - Where faeces is excreted through.
• Rectum - Last part of large intestine that connects to anus.
• Liver - Processes and digests food and removes toxic substances. Filters out harmful waste, stores vitamins and glycogen, produces bile.
• Bile duct - Carries bile from gall bladder into upper part of small intestine
• Pancreas - Exocrine function: helps with digestion. Endocrine function: helps with regulating blood sugar.

Question 2

Describe mechanical digestion.

Answer 2

Chewing:
- Physical breakdown of food into smaller pieces using teeth to form bolus shape.
- Saliva lubricates food, moistening it and tongue pushes chewed food to back of buccal cavity.
- Food is swallowed and enters oesophagus to undergo peristalsis.

Stomach:
- Inner stomach layer (rugae) allow stretching of stomach to accommodate for large meals.
- Rugae help to grip and move food.
- Muscles of stomach churn food = breaking food into smaller pieces (chyme).

Question 3

Describe chemical digestion.

Answer 3

Mouth:
- Saliva produced contains amylase which begins breakdown of starch into maltose.

Stomach:
Gastric glands produce gastric juice that has HCL and pepsin.

• HCL destroy harmful microorganisms & provide optimum conditions for pepsin
• Pepsin enzyme breaks proteins into polypeptides.
• Mucus also produced to protect stomach wall from corrosive acid.

Small intestine (Duodenum, Jejunum - where nutrient absorption takes place - and ileum):

• Chyme enters duodenum & mixes with bile (emulsifies fats in chyme into smaller droplets to allow absorption to take place faster)
  and with pancreatic juice (released by pancreas and contains alkaline salts - neutralise acidic food from stomach - and digestive enzymes that breakdown fats into fatty acids and glycerol, protein into amino acids and complex carbs into simple sugars

Question 4

What is absorption and how is the small intestine adapted for absorption?

Answer 4

Absorption - Obtaining oxygen and nutrients from food to be absorbed into bloodstream and delivered to cells for respiration.

Adaptations:
1. Length - Long enough to provide enough time for absorption, larger surface area so absorption can take place faster & efficiently
2. Folds in inner layer - Large surface area maximising absorption of nutrients.
3. (Micro)villi - Found on epithelial cell increasing its surface area. Epithelium is one cell thick = short diffusion distance for absorption

Question 5

What is absorption and assimilation and the liver’s role in this?

Answer 5

Absorption: Process of digested food molecules entering bloodstream and lymphatic system.

Assimilation: Process where absorbed nutrients from digested food molecules are taken up by cells to be used.

• Liver sorts and distributes nutrients required to cells
• Liver also removes nitrogen-containing part of amino acids = urea (deamination)
• Liver neutralises and destroys drugs and toxins (detoxification)

Question 6

What is Irritable Bowel Syndrome, symptoms, causes, risk factors, treatment options, monitoring and impacts?

Answer 6

Condition that affects the digestive system, specifically the way in which the the stomach and intestines function. Symptoms include: pain, cramping, diarrhoea, constipation, bloating, excessive wind, change in bowel habits.

Causes: abnormal muscle contractions, inflammation in intestine due to immune response, severe infection and changes in gut bacteria.

Risk factor: previous digestive illness, family history

Treatment:
- Buscopan ( relieves stomach cramps)
- Peppermint oil ( relieves stomach cramps)
- Antidepressants ( eases IBS symptoms)
- Avoid high fibre foods (brown bread/rice)
- Avoid hard to digest foods ( beans, onions)
- Sleep enough and stay hydrated

Monitoring:
- Colonoscopy (long flexible tube with light and video camera to examine digestive organs)
-Ultrasound (examine liver and abdominal organs using sound waves that help form image)

Impacts:
- Can make sleep difficult = fatigue and lack of energy for school or work , flatulence = cause embarrassment socially, feel sick and nauseous

Care needs: Dietician recommends foods not easily broken down or CBT.

Question 7

What is coeliac disease , symptoms, causes, risk factors, treatments, monitoring, impacts and care needs?

Answer 7

Condition where immune system reacts abnormally to gluten and attacks its own tissues, causing inflammation of the small intestine.

Symptoms:
- Stomach cramps = pain
- Bloating
- Flatulence
- Diarrhoea & Constipation
- Unexplained weight loss.

Causes:
- Genetic mutation affecting immune system
- Family history

Risk Factors:
- Genetic disorders e.g. Down syndrome
- Having another autoimmune condition

Treatments:
- Anti-inflammatory antibiotics for itchy rash
- Exclude all gluten-containing food e.g. bread, cakes, biscuits, pasta, cereals (lifestyle change would include vitamin supplements and taking care when eating out)

Monitoring:
- blood test to confirm
-biopsy of small intestine
- endoscope to collect samples of small intestine and check under microscope.

Impacts:
- Restricted diet
- Lack of socialising

Question 8

What is gallstones , symptoms, causes, risk factors, treatments, monitoring, impacts and care needs?

Answer 8

Hard deposits usually made of cholesterol that form in the gall bladder (where bile is stored) or bile duct and cause a blockage.

Symptoms:
- abdominal pain
- nausea
- vomiting
- flatulence
- increased body temp
-jaundice
- itchy skin

Causes: An imbalance in the chemical makeup of bile as it contains too much cholesterol or bilirubin = formation of tiny crystals and then overtime solid stones.

Risk factors:
- overweight
- aged 40 and older
- pre-existing condition that affects bile i.e. liver cirrhosis
- family history

Treatment:
- medication to dissolve gallstones: side effects, don’t cure forever, long term so frustration
- keyhole surgery: to remove gall bladder
- procedure using shockwaves to break gallstones into smaller fragments so easily dissolvable
- avoid high saturated fat foods

Monitoring:
- Ultrasound using soundwaves to creates images of inside body
- Procedure involving dye given into bloodstream/ bile ducts.
- Dye visible using Xray and can detect any abnormalities of bile duct.

Impacts:
- loss of appetite
- lack of sleep due to pain
-restricted social events due to fear of embarrassment
- unable to do high intensity exercise due to pain

Care needs:
- home help due to inability to perform daily tasks as a result of severe pain