midterm study Flashcards
(28 cards)
What are the four categories of enzymatic reactions?
- Oxidation-reduction reactions.
- Hydrolysis dehydration reactions
- Addition-subtraction exchange reactions
- Ligation reactions
Describe the main ways that cells can regulate metabolism?
- Controlling Enzyme concentration
- producing modulators that change reaction rates
- Using 2 different enzymes to catalyze reversible reactions
- compartmentalizing enzymes within cellular organelles
- Maintain an optimum ratio of ATP to ADP
explain the basics of glycolysis?
- Does not require oxygen
- glycolysis takes place in the cytosol, 2 molecules of glyceraldehyde-3-phosphate (G3P) is formed for every glucose molecule (a total of 4 ATP is produced, a net gain of 2 ATP)
How does the electron transport system worK?
- takes high energy electrons from NADH and FADH2
- energy is used to create ATP by creating an H gradient
- oxygen is the final acceptor of electrons and H to make h2o
- H concentrated between the two mitochondrial membranes
- the flow of H (down gradient) through ATP synthase in membrane results in a transfer of energy to make ATP
describe the control of hormone release in the human body as a reflex pathway
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Describe the main patterns of physiological communication
- simple diffusion across small distances
- Widespread distribution of molecules through the circulatory system
- Rapid, specific delivery of messages by the nervous system
what are the main classes of hormones?
- Peptide/protein hormones
- steroid hormone
- Amine Hormones
compare and contrast peptide and steroid hormones
peptide hormones are the most common hormones in the body, they are composed of linked amino acids and are water-soluble and lipophobic. While steroid hormones are derived from cholesterol and are lipophilic and hydrophobic
describe the control of hormone release in the human body as a reflex pathway
- A stimulus is detected by a sensor, this sensor sends an afferent signal to the integrating center
- the integrating center is going to compile all the information it has received and send out an efferent signal to target tissues.
- the target tissues then initiate a response, when the response is achieved we seed a negative feedback loop to turn off signal
List the anterior pituitary hormones. What are their functions?
- Prolactin - Milk production & breast development
- Luteinizing Hormone = sex hormones, ovulation
- Adrenocorticotropic hormone - promotes the growth of the adrenal cortex
- thyroid-stimulating hormone - stimulates the secretion of thyroid hormones & growth of thyroid gland
- follicle stimulating hormone - stimulates growth and development of ovarian follicles
- growth hormone - acts on body tissues
What are the 3 basic patterns of endocrine pathology? Provide an example for each?
- Excess
- Deficiency
- Abnormal responsiveness of target tissues
Describe the route that a piece of food will take through your digestive tract and the main events that will occur in each place
- Oral cavity - receives food, saliva helps to start the breakdown of food
- Esophagus - muscular contractions move food through the thorax and into the abdomen
- stomach - food gets mixed with acid and enzymes to make chyme
- small intestine - where most digestion takes place
- colon - chyme is converted to semi-solid feces
- rectum - movement of feces into rectum triggers defecation reflex
- anus - exit for feces
explain the main stages of integrating GI function?
- Cephalic Phase - the anticipation of food
- Deglutition (swallowing) - going to push the bolus of food into the esophagus
- Gastric Phase - consists of storage, digestion, and immune functions
- Intestinal Phase - peristalitic contractions and segmental contractions move chyme along the tract
How is glucose absorbed from the intestinal lumen?
Via a glut 2 transport protein, this occurs via secondary active transport
explain how different macronutrients are digested and absorbed.
- Carbohydrates: must be broken down or digested before they can be absorbed
- Proteins: broken down into small peptides and amino acids by endo/exopeptidases
- Fats: digestion facilitated by bile salts
What are the three types of reflexes in the regulation of GI function?
- Long Reflexes
- Short reflexes
- Reflexes involving GI peptides
what is the first law of thermodynamics?
energy cannot be created nor destroyed
describe the factors that influence metabolic rate, and what their impact is
- Age (Decreases as we get older)
- Sex (Males > females)
- body composition (more muscle, less fat)
- activity level
- Diet (protein > fat)
- hormones
- genetics
explain what is happening with all of the macronutrients when the body is in a fasted state
- Carbohydrates: glycogen in the liver is used for the entire body
- Proteins: can become energy sources when we are in extended fast (proteins can be used to produce ATP, or to make new glucose)
- Fats: broken down to glycerol
Explain what is happening with all of the macronutrients when the body is in a fed state?
- Carbohydrates: glucose is the main source of energy for ATP production in fed state (absorbed in intestine)
- amino acids: taken to the liver by hepatic portal system
- Fats: used for energy and stored in adipose tissue
what are the factors affecting insulin secretion? What are the functions of insulin?
- Increase in plasma glucose
- increase in plasma amino acids
- feedforward effect of GI hormones
- Parasympathetic activity
- sympathetic activity
Insulin lowers blood glucose
describe the interaction between insulin and glucagon
After a meal, insulin spikes and glucagon decreases. While after exercises, glucagon spikes, and insulin decreases
Compare and contrast carbohydrate metabolism in the fed and fasted states.
in the fed state, glucose is the main source of energy for ATP production. in the fasted state, we get our energy from glycogen stores in the liver
Compare and contrast lipid metabolism in the fed and fasted states.
In the fasted state lipids are broken down into glycerol, while in the fed state chylomicrons enter the blood via lymphatics
