Digestion, Nutrition & Obesity Flashcards
What is a nutrient?
substance in food that are used to promote normal, growth, maintenance and repair (metabolised for building blocks or energy)
What are the uses of carbohydrates in the body?
Glucose (monosaccharide) = fuel
What can happen if you have excess carbohydrates in the body?
- depressed brain function and neurone death
- obesity
- diabetes mellitus
- dental cares
- gastrointestinal irritation
- excess glucose converted to fat and glycogen
What can happen if you have deficient carbohydrates in the body?
- tissue wasting
- metabolic acidosis
What are the uses of lipids in the body?
- provides protection for organs
- integral part of myelin sheaths
- cholesterol used in plasma membranes
- major energy fuel of skeletal muscle
What can happen if you have deficient lipids in the body?
- weight loss
- problems controlling heat
- poor growth, skin lesions
What can happen if you have excess lipids in the body?
- obesity
- increased risk of cardiovascular disease
- atherosclerosis
What are the uses of proteins in the body?
- tissue maintenance and growth
- rate protein synthesis = breakdown
- positive nitrogen balance needed needed for pregnant women or growing children
- negative nitrogen balance (seen in physical and emotional stress)
What can happen if you have deficient proteins in the body?
- profound weight loss
- tissue wasting
- anaemia
- oedema
What can happen if you have excess proteins in the body?
- obesity
- enhanced calcium excretion
- bone loss
What are vitamins?
organic compounds needed for growth and good health
What are electrolytes?
chemicals that regulate nerve and muscle function, hydrate the body, balance blood acidity and pressure, and help rebuild damaged tissue
What are some examples of electrolytes?
- Sodium
- Potassium
- Calcium
- Bicarbonate
- Magnesium
- Chlorine
- Phosphate
What is anabolism?
reactions that build larger molecules and structures
What is catabolism?
process of breaking down, complex structures into simpler ones
What is oxidation?
food molecules react with oxygen present in our body causing formation of water and carbon dioxide and release of energy
What are the short term controls of food intake?
- Vagus nerve
- nutrient signals
- gut hormones
What are the long-term controls of food intake?
- insulin
- leptin
What is basal metabolic rate (BMR)?
Energy of cost of living
- reflects the need to maintain essential activities like breathing and maintaining organ function
- controlled by thyroxine hormone
What is metabolic rate?
kilocalorie consumption required to fuel all ongoing activities
What does the digestive system consist of?
- Mouth
- Oesophagus
- Stomach
- Liver
- Gall bladder
- Pancreas
- Small intestine – duodenum, jejunum and ileum
- Large intestine
- Anus
What are the major processes occurring in the digestive system?
- Ingestion
- Secretion
- Mixing and Propulsion
- Digestion
- Absorption
- Defecation
What are the (3) mouth functions?
- ingest food
- masticate (chewing)
- mix food with saliva
What are the (3) functions of the salivary glands?
- cleanses mouth
- dissolves food chemicals to facilitate taste
- moistens food to enable bolus formation
What are the 2 phases of deglutition (swallowing)?
- Buccal phase – bolus formation
- Pharyngeal-oesophageal phase – tongue blocks mouth, epiglottis closes and upper oesophageal sphincter relaxes to allow food into oesophagus
What (2) muscles help push food into the oesophagus?
- oropharynx
- laryngopharynx
What does the epiglottis do?
closes to prevent food going into the trachea and direct it to the oesophagus
How does the oesophagus connect to the stomach?
via the oesophageal hiatus and the cardiac sphincter
What is propulsion?
peristalsis pushes food to fundus
What is grinding?
vigorous mixing motion close to pylorus
What is retropulsion?
pylorus forced back to the stomach
What are the (6) functions of the liver?
- Metabolism of carbohydrate, lipid and protein (maintains normal blood glucose level)
- Detoxification (removes and excretes alcohol and some drugs; chemically alters some hormones)
- Storage for nutrients (stores glycogen, vitamins A, B12, D, E + K; minerals like Fe and copper)
- Phagocytosis (breaks down worn out red blood cells, white blood cells and some bacteria)
- Activation of vitamin D
- Production of bile
What is the purpose of bile?
helps with digestion by breaking fats into fatty acids
What is the purpose of the pancreas?
- Supplies most of the enzymes that digest chyme
- Exocrine part produces pancreatic juice of enzymes
- Supplies bicarbonates that neutralise stomach acids
What is the purpose of the small intestine?
major site for digestion and absorption due to its invaginated structure (folds of mucosa are lines with villi)
Between the villi of the small intestine are intestinal crypts containing what (2) things?
- Enterocytes = absorb nutrients and electrolytes
- Goblet cells = secrete mucous
What is the purpose of the large intestine?
mainly to absorb water
What is an appendix?
- contains lymph tissue
- involved in immunity and as a storehouse of bacteria for the gut
What initiates the defecation reflex of the rectum?
stretching
How does defecation take place?
- faeces forced into rectum, distends the rectal wall
- this stretches it and initiates the defecation reflex
- the sphincter relaxes and rectal walls contract to expel faeces aided by glottis closing and contraction of diaphragm
What BMI is considered overweight?
greater than or equal to 25
What BMI is considered obesity?
greater than or equal to 30
How do you calculate BMI?
Person’s weight in kilograms divided by the square of his height in meters (kg/m2).
What are (5) ways to measure body fat?
- BMI
- DEXA (dual-energy X-ray absorptiometry) scan
- Bathroom scales
- Waist measurement
What is the fundamental cause of obesity and being overweight?
an energy imbalance between calories consumed and calories expended
What causes obesity and being overweight?
- Increased intake of energy-dense foods that are high in fat and sugars
- Increase in physical inactivity due to the increasingly sedentary nature of work, changing modes of transportation, and increasing urbanisation
What factors can cause someone to be overweight?
- genetic
- socioeconomic
- ethnicity
- lack of exercise
- sedentary lifestyle
- diet
- medications
- stress + mental illness
- poor sleep
How does a patient manage their obesity?
- lifestyle interventions
- diet
- exercise
- behavioural therapy
- medical managements (appetite suppressant)
- bariatric surgery
- patient education
