Digestion & Metabolism Flashcards
(74 cards)
What is digestion?
The process of breaking down food into absorbable nutrients.
What is metabolism?
Utilizing nutrients from digestion to generate cellular energy.
What is the sequence of energy processes after digestion?
Digestion -> Absorption -> Metabolism
What is a calorie?
The amount of energy needed to raise the temperature of 1 gram of water by 1°C.
What is the “Eat or Exercise Activity Thermogenesis”?
Energy expended through physical activity, which can be increased by exercise.
What is the “Thermic Effect of Food”?
The energy required to digest food. Protein digestion requires more energy.
What is Basal Metabolic Rate (BMR)?
The amount of energy expended while at rest. It can increase in heat.
What are some factors affecting BMR?
BMR varies by individual, is correlated with body size, is higher in men, and decreases with age.
What is the digestive system responsible for?
Breaking down food into absorbable nutrients: amino acids, lipids, mono/disaccharides, vitamins.
What are the key steps in digestion?
- Mouth
- Stomach
- Small intestine
What happens in the mouth during digestion?
Chewing (mechanical digestion) and saliva secretion (chemical digestion).
What are the key components of saliva?
Amylase, lingual lipase (for lipids), lysozyme, IgA, epithelial cells, biomarkers.
What is the role of the epiglottis?
A cartilage flap that prevents food from entering the trachea during swallowing.
What is the function of the esophagus?
A muscle-lined tube that helps food travel to the stomach in just a few seconds.
What happens in the stomach during digestion?
Both chemical and mechanical digestion. The stomach holds food for 1-4 hours.
What enzymes are involved in stomach digestion?
Hydrochloric acid and pepsin (breaks down proteins).
How long can the stomach hold food and what is its pH?
The stomach holds food for 1-4 hours, and its pH is around 1-3, aiding in digestion and killing bacteria.
What are the three salivary glands?
Parotid, submandibular, and sublingual glands.
What is the role of the salivary glands?
They secrete saliva, which aids swallowing and begins chemical digestion.
What is the function of the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles?
They are involved in the mechanical breakdown of food by chewing.
What is the role of the tongue in digestion?
The tongue helps in swallowing and the mechanical breakdown of food.
Why is the pH of saliva important?
The near-neutral pH (~6.7) helps prevent tooth decay and acts as a buffer.
What does the stomach’s acidity do?
It helps break down proteins and kills most bacteria and viruses.
What are the layers of muscles in the stomach?
The stomach has three muscle layers that are cross-layered, aiding in food breakdown.