Metabolism and Hormonal Regulation Quiz

Integration of Metabolism

• Metabolism is the sum of all chemical reactions in an organism
• Integrated metabolic processes in the body involve multiple organs working together

Cellular Level Metabolism

• Enzymatic roles, flux of metabolites in pathways, regulation through feedback mechanism and transport of metabolites
• Various specific tissues and organs play different roles
• Hormonal regulation of metabolism affects the whole organism and body mass control

Neuronal vs. Hormonal Signaling

• Neuronal signaling occurs through neurotransmitters affecting nearby cells (short distance)
• Hormonal signaling uses hormones traveling through the bloodstream to affect distant cells or organs (long distance)

Hormone-Receptor Interactions

• Varying receptor types on different cells lead to varying responses
• Hormones bind to specific receptors with high affinity, needing only low hormone amounts
• Receptors are intracellular or extracellular, affecting cell functions

"Downstream" Events, Following Hormone Binding

• Secondary messengers, like cAMP and IP3, are released inside the cell and affect enzyme activity
• Receptor Tyrosine Kinase activity leads to cell responses
• Hormone-gated ion channels can open or close to change membrane potential
• Adhesion receptor interactions affect the cytoskeleton
• Steroid hormone receptors in the nucleus can change gene expression

Three Classes of Mammalian Hormones

• Endocrine hormones are released into the blood stream and travel to affect distant cells or organs
• Paracrine hormones diffuse in the extracellular space and affect nearby cells
• Autocrine hormones affect the cell producing them

Peptide and Amine Hormones

• Peptide hormones include insulin, glucagon, somatostatin, etc.
• Epinephrine (adrenaline) is an amine hormone
• They bind to membrane receptors; this activates second messenger pathways impacting many targets

Insulin as a Peptide Hormone

• Synthesized on ribosomes in the pancreas, processed into active form
• Stored in secretory vesicles in the pancreas
• Has 51 amino acids; A and B chains are similar across species

Newer Insulins

• Rapid-acting analogs (Lispro, Aspart, Glulisine) have faster onset
• Long-acting analogs (glargine, detemir) have extended duration of action
• Analogs change amino acid sequence to modify activity

Epinephrine and Norepinephrine

• Catecholamine hormones made in the adrenal medulla from L-tyrosine
• Stored and released like peptide hormones
• Bind to extracellular receptors to trigger secondary messenger systems similar to peptide hormones

Paracrine Hormones

• Include prostaglandins, thromboxanes, leukotrienes
• Made in response to stimuli near the site of release
• Affect local tissues (inflammation, smooth muscle contraction, etc.)

Steroid Hormones

• Derived from cholesterol
• Bind to carrier proteins to travel through the bloodstream
• Enter the nucleus and act on nuclear receptors to change gene expression
• Some bind plasma receptors affecting various tissues

Retinoid Hormones

• Derived from vitamin A (retinol), which derives from –carotene
• Act on nuclear receptors affecting cell growth and differentiation in tissues with rapid growth

Thyroid Hormones

• Thyroid hormones (T3 and T4) have iodine atoms
• T4 gets converted to T3
• Act on nuclear receptors changing enzyme expression and energy regulation
• Lack of iodine can lead to goiter

Nitric Oxide

• Made from arginine
• Acts locally near release
• Enters cells and activates guanylyl cyclase
• Increases cGMP, relax smooth muscle and lowering blood pressure

Major Endocrine Glands

• Brain (hypothalamus, pituitary)
• Thyroid, parathyroid
• Adrenals, pancreas, adipose tissue
• Ovaries/Testes

Top-Down vs. Bottom-Up Hormonal Signaling

• Top-down signals originate in the brain and affect the body
• Bottom-up signals originate in the body and affect the brain

Hormones and Target Tissues

• Overview of hormone pathways, targets, roles

Muscle Metabolism

• Stores relatively small amounts of glycogen (1–2% of mass)
• Heart muscle is primarily aerobic
• Light activity uses fatty acids and ketone bodies
• Heavy activity uses glycogen and produces lactate

Cori Cycle

• Cycle between muscle and liver involving lactate
• Muscle uses glycogen for energy during activity
• Liver converts lactate into glucose for further use
• Uses ATP during recovery

Brain Metabolism

• Requires constant energy from glucose or ketone bodies
• No glycogen storage, relying on incoming energy sources
• Important for action potentials

Blood Insulin Increased (Well-fed State)

• Increased insulin to control blood glucose levels
• Glucagon decreases, allowing for glucose being used by cells

The Well-Fed Lipogenic Liver

• Insulin promotes glycogen synthesis, inhibits fat breakdown in adipose tissue
• Muscle cells take up glucose
• Liver takes up glucose, synthesizes glycogen
• Adipocytes, take up glucose, use it to create glycerol for fat synthesis

Effects of Insulin on Blood Glucose

• Promotes glucose uptake in muscle, adipose tissue
• Enhances glycogen synthesis in liver and muscle
• Suppresses glycogen breakdown
• Promotes glycolysis, and acetyl-CoA production

Insulin and Amylin

• Insulin and amylin are secreted together by beta cells
• Amylin affects gastric emptying, glucagon secretion and appetite

The Fasting State

• Glycogenolysis and gluconeogenesis contribute to the glucose levels
• Adipose releases fatty acids
• Muscle breaks down proteins, amino acids to glucose and ketone bodies
• Brain uses ketone bodies and glucose for function

ATP Equivalents

• ATP produced from glucose metabolism and ketone bodies
• Caloric values associated with carbohydrates, protein, and fats

Available Metabolic Fuels

• Comparison of metabolic fuel availability between normal and obese individuals

Fuel Metabolism in Prolonged Fasting and Type 1 Diabetes

• Fat becomes the primary energy source when glycogen stores are depleted
• Ketone bodies increase while blood glucose decreases
• Insulin output decreases but glucagon increases

Graph of Plasma Concentrations during Starvation

• Graph of various substances' concentrations over days of starvation

Tissues Involved (Well-fed vs. Starvation)

• Shows the involved metabolic pathways in the body during both states

Drugs and Diseases

• Includes diabetes, inflammation, and various other conditions, and their respective drug therapy

Nutritional Quality of Proteins

• Essential amino acids simultaneously needed for protein synthesis
• Quality assessed through essential amino acids, digestibility, and chemical score
• Animal proteins generally have higher biological value

Nutritional Quality of Proteins (Quality, Source)

• Comparing the chemical score and biological value of proteins in various food sources
• Animal sources tend to have higher biological values.

Plant Protein Quality

• Plant proteins often have lower biological value than animal sources
• Combining plant protein sources with complementary amino acid profiles can be beneficial

Nutritional Quality of Proteins, Obesity

• Emphasizes that obesity results from excess caloric intake over expenditure
• 1 pound of fat equates to 3500 calories

Test your knowledge on the integration of metabolism, hormonal regulation, and the differences between neuronal and hormonal signaling. This quiz covers essential concepts related to metabolic processes, receptor interactions, and the roles of different organs. Perfect for students studying biology or physiology.