Class 20 Flashcards
What is Metabolism?
The highly regulated processes through which nutrients are broken down, transformed, & otherwise converted into cellular energy to sustain processes of life & health.
The Body’s Energy Systems (How is energy derived & why is it important?)
Body needs consistent, reliable, 24/7 supply of energy for all its physical, mental & emotional activities. Energy is derived from m food we eat. If not, body utilizes stored energy from previously ingested food, or as last resort, breaks down its own tissues for fuel.
What is the function of the Digestive System?
Breaks down food into usable energy units:
● Proteins into amino acids, which are key component of enzymes, essential tissue building blocks, & important in transport of nutrients, hormones, etc.
● Carbohydrates (starches) into glucose, which is body’s primary fuel (easiest to use to create ATP, which is essential cellular energy source)
● Oils/fats into fatty acids, can be used as alternative energy sources if body is low on glucose, or converted into adipose, body’s long-term energy storage form; fatty acids are also important for building cell membranes & organelles as well as molecules such as hormones, ketone bodies & triglycerides
What are triglycerides?
Major form of fat storage in body; built from fats and carbohydrates. Food calories that are not used immediately by body tissues are converted to triglycerides & stored in fat (adipose) cells. Hormones regulate triglyceride release from adipose tissue to help meet body’s needs for energy. Hypertriglyceridemia (excess volume of triglycerides in the blood) is linked to coronary artery disease.
What is Hypertriglyceridemia?
Excess volume of triglycerides in blood
What is the Circulatory System?
● Responsible for delivery of cells’ supply of oxygen, which is essential element for all chemical processes, including digestion.
● Transports nutritive particles such as glucose from digestive tract to body tissues
● Transports metabolic wastes from tissues to organs of re-processing or elimination (lungs, kidneys, liver)
What is Liver?
● Produces bile (needed to break down ingested oils/fats)
● Glucose regulation: can build glucose (from fatty acids) & break it down, also converts glucose into storage form GLYCOGEN
● Stores vitamins & minerals
● Synthesizes proteins for use in body
● Helps build & break down fat stores
● Metabolizes hormones & drugs
● Converts fatty acids into KEYTONES
What are ketones?
When glucose supplies are low, body begins to break down fat cells for energy. Process produces fatty acids as by-product, some of which are essential to metabolism, but some are quite dangerous to health. Liver can convert fatty acids into ketones, which can keep heart, brain & muscles fueled. However, ketones are acidic (lower pH of body fluids). Ketone build-up blood, called ketoacidosis, can be life threatening.
What is ketoacidosis?
Ketone build-up blood
The preferred cellular fuel source is?
*Glucose.
If glucose availability is insufficient, amino acids, fatty acids & triglycerides are utilized. Glucose utilization is less complex & most efficient, & involves the fewest potentially detrimental by-products.
What is the pancreas?
Part of endocrine system, large gland with several major roles to play in digestion & glucose dynamics.
● synthesizes digestive enzymes involved in breaking down of all digestible food types
In addition to helping break down proteins, fats & starches, pancreas also helps neutralize chyme. Chyme (thick semi-fluid mass of partly digested food) passed from stomach to duodenum. Acidity has potential to damage walls of small intestine if pH is not balanced.
● synthesizes hormones involved in blood glucose
regulation
→ alpha cells release GLUCAGON in response to low blood glucose
→ beta cells release INSULIN in response to high blood glucose
→ delta cells (along with various other sources) release SOMATOSTATIN, regulator hormone. It’s employed to oversee endocrine gland activities, by inhibiting hormone secretion. Influences release of many hormones, e.g., growth hormone, digestive hormones like gastrin & secretin, glucagon & insulin. So, it can control processes Eg. stomach emptying & nutrient digestion, absorption & utilization. These hormones are produced in area
of pancreas tissue called ISLETS OF
LANGERHANS.
What is insulin?
● hormone that creates ‘well fed’ state in body; without insulin body cannot get energy it needs from food it consumes
● released in response to GI enzyme levels (part of digestive cycle), to high blood glucose, & to parasympathetic nervous system stimulation
● facilitates passage of glucose from bloodstream into cells by stimulating cell wall insulin receptors
N.B. Blood cells, most brain cells do not require insulin for glucose uptake.
● increases uptake of amino acids by cells
What is the function of Insulin?
● anabolic in function:
→ stimulates conversion of glucose not needed immediately into its storage form glycogen; glycogen storage occurs in liver, where it’s accessible to body as needed, & in muscle cells, for future use by muscle
→ stimulates liver to convert excess glucose to fatty acids & then to triglycerides
→ stimulates conversion of amino acids to proteins
After meal, glucose moves from intestinal tract into blood. With rising blood glucose level, insulin is released to promote movement of glucose molecules into tissue cells, where they are used for energy production. Insulin then prompts liver to either store remaining excess blood glucose as glycogen (for short-term energy storage) and/or use it to produce fatty acids. Excess fatty acids are synthesized into triglycerides to form basis of adipose, more concentrated, longer term form of energy storage.
What is Glucagon?
● creates ‘find food’ state in body
● released in response to low blood glucose & to SyNS stimulation (stress connection)
● catabolic in function:
→ facilitates conversion of liver glycogen stores to glucose
→ facilitates breakdown of amino acids & stored fat (adipose)
What is Diabetes?
Disorder of carbohydrate, protein & fat metabolism resulting from an imbalance between insulin availability & insulin need.