Catabolic Pathways release energy by breaking down complex molecules into smaller products; exergonic

Anabolic Pathways consume energy to build complicated molecules from simpler ones; endergonic

ex: the synthesis of a protein from amino acids

- energy currency in a cell

- collects and stores energy from nutrients of organisms

- used as an energy source for reactions

3 main factors:

- basal metabolic rate

- amount of physical activity

- thermic affect of food

- liver has 100% of the metabolic burden when fructose is consumed opposed to the 20% burden from glucose.

- every cell in the body utilizes glucose, therefore much of it is "burned up" immediatly after consumption. in contrast fructose is turned into free fatty acids, which get stored as fat.

- glucose supresses hunger and fructose has no effect on hunger

- building blocks for protien

- body can't produce these amino acids so the diet must supply them

- allow the body to build and repair tissue

- form enzymes important for many internal functions

- needed to support good health, but can't be synthesize by the body so diet must supply these fatty acids

- most of our body cells use these fats as a direct source of enery

- goiter

- scurvy

- increases the surface area of food by breaking it into smaller, similar-sized pieces for easier digestion

ex: mastification (chewing)

the breaking down of food particles through chemical reactions

begins when the salivory glands secrete water, mucus, amylase, and lipase

1. smell of food triggers the salivary glands to secrete saliva
2. after food enters the oral cavity, mechanical digestion and chemical digestion begin
3. after food is broken down into smaller pieces it is considered a bolus and moves to the stomach via pharynx and esophagus
4. coordinated contractions churn the bolus and gastric juices changing it from a bolus to chyme
5. chyme exits the stomach entering the first section of the small intestine, the duodenum
6. secretions neutralize the acidic pH of the gastric juices and further break down the chyme
7. absorption of water and nutrients occur in the remainder two sections of the small intestine
8. chyme moves from the small intestine to the large intestine where more water is absorbed and waste is compacted and moved to the rectum to await elimination

- hormone released from the stomach

- stimulates hunger

- eating causes levels to decrease

- hormone secreted by the small intestine

- promotes satiety

- levels rise during and after meals

- hormone secreted by the small intestine in proportion to caloric content of food

- decreases hunger

- injections of the hormone can be appetite suppressant

- hormone secreted by the adipose tissue

- affects satiety 

- reduces appetite and increases metabolic rate

- insulin stimuates the adipose tissue to secrete leptin

- secretion increases as stored fat increases

- hormone secreted by the pancreas

- promotes anabolism

- inhibits breakdown of fat and protein

- inhibits secretion of glucagon

- stimulates insertion of GLUT4

- hormone secreted by the pancreas

- helps to elevate glucose levels

- stimulates breakdown of glycogen in the liver converting it back to glucose, which raises blood glucose levels to normal 

- insulin converts glucose to glycogen and stores it in the liver for future use

- when blood glucose levels are low the pancreas can use the glycogen in the liver to convert it back to glucose, raising blood glucose levels

- insulin works to lower glucose levels, converting glucose to glycogen

- glucagon works to elevate glucose levels by breaking down glycogen

- as a result, they keep eachother balanced

- accounts for 5% of all diabetics

- insulin dependent

- autoimmune disease that destroys insulin cells

- impaired insulin secretion by the pancreas

- glucose is unable to enter resting muscle or adipose cells

- fast progression and can occur at any age

- fatty acids are converted to ketone bodies, producing ketoacidosis

- accounts for 95% of all diabetics

- insulin independent

- insulin has little affect on the body

- slow to develop

- not usually accompanied by ketoacidosis

- treatable by exercise and diet

rare mutations:

- insulin receptor

- glucose transporter

- signalling proteins

- inactivity

- obesity

- stress

- insulin

- glucagon

- between 65-105 mg/dl

- insulin and glucagon prevent levels from rising above 170 mg/dl after meals or below 50 mg/dl between meals

• metabolic balance

- feeding promotes anabolism

- fasting promotes catabolism

• inverse relationship between insulin and glucagon secretion

- insulin secretion rises, glucagon falls during food absorption

- opposite occurs during fasting