HLTB22 Midterm

• Cells of organisms need to communicate with each other to regulate their development and organize growth and cell division
• Hormones act as messengers between cells, telling them what's happening elsewhere and how they should respond
• Endocrine system consists of:

  • Glands located throughout the body
  • Hormones made by the glands and released into the bloodstream or the fluid surrounding cells
  • Receptors in various organs and tissues that recognize and respond to the hormones
• Hormones control many bodily processes such as:

  • Metabolism
  • Homeostasis
  • Growth and development
  • Sexual function
  • Reproduction
  • Sleep-wake cycle
  • Mood
• Endocrine glands contain cells that release their products (hormones) just outside the cells (into the extracellular fluid), which diffuse directly into the bloodstream
• Hypothalamus:

  • Links the endocrine and nervous systems together
  • Drives the endocrine system
• Pituitary gland:

  • Receives signals from the hypothalamus
  • Produces hormones like Antidiuretic hormone (ADH), Oxytocin (OT), Growth Hormone (GH), Luteinizing hormone (LH), and Follicle-stimulating hormone (FSH)
• Thyroid gland:

  • Produces hormones like Thyroid hormone (TH) and Calcitonin (CT)
• Adrenal gland:

  • Located on each kidney
  • Produces hormones like Epinephrine ('adrenaline')
• Gonads:

  • Testes produce Androgens (testosterone) and develop male sex characteristics
  • Ovaries produce Estrogens and progesterone and develop female sex characteristics
• Insulin is a hormone made by the pancreas that enables the body's cells to absorb sugar (glucose) from the bloodstream for energy
• Diabetes is a complex chronic metabolic disease characterized by high fasting blood glucose, with two major forms: type 1 and type 2
• In Type 1 diabetes, insulin is no longer secreted, while in Type 2 diabetes, insulin is no longer able to facilitate glucose entry into cells for energy production
• Insulin insufficiency in Type 1 diabetes is due to a lack of insulin production by the pancreas, while insulin resistance in Type 2 diabetes is due to reduced or dysregulated insulin receptor signaling
• Hemoglobin A1c test (HbA1c) assesses average glucose levels over a 2-3 month period and is used to monitor blood glucose levels in diabetics
• Pre-diabetes is defined as impaired fasting glucose and/or impaired glucose tolerance, where blood glucose is higher than normal but not high enough to meet the diagnostic criteria for type 2 diabetes
• Diabetes increases the risk of developing comorbidities and various health complications, impacting physical and cognitive health
• Genetics play a role in the risk of developing Type 1 diabetes, with environmental factors like viral infections also implicated as possible triggers
• Factors that contribute to the increased risk of developing type 1 diabetes among Caucasians compared to other ethnic groups:

  • Genetic susceptibility
  • Family history
  • Certain environmental triggers
• Management of Type 1 Diabetes:

  • Insulin replacement by daily injection to maintain blood glucose levels
  • Timing and dosing of insulin, diet patterns, and activity levels to prevent hyperglycemia leading to diabetic ketoacidosis and hypoglycemia leading to diabetic coma
  • Life-long daily insulin replacement and glucose monitoring are required for type 1 diabetics
• Type 2 Diabetes:

  • Represents approximately 90-95% of all cases of diabetes
  • Insulin is still produced and secreted by the pancreas but its impact on glucose uptake is impaired
  • Elevated blood glucose occurs due to a mismatch between the amount of insulin produced and secreted and the amount needed to maintain normal blood glucose levels
  • This mismatch is caused by target tissue insulin resistance
• Risk Factors for Type 2 Diabetes:

  • Obesity is the strongest modifiable predictor of type 2 diabetes
  • The cause and effect relationship between obesity and type 2 diabetes has been demonstrated in several studies
  • Compared with a body mass index (BMI) of 21 kg/m2, the relative risk of developing type 2 diabetes rises exponentially with increasing BMI
• Dietary Factors:

  • Dietary factors influence the risk of developing type 2 diabetes
  • Factors such as glycemic index, glycemic load, type of fat, type of carbohydrate, dietary fiber, and dietary additives have been investigated in experimental and epidemiologic studies
• Glycemic Index:

  • A measure of postprandial increase in blood glucose due to intake of a specific food relative to that induced by glucose
  • Ranks foods based on their glycemic impact relative to glucose
  • Glycemic index and glycemic load have been widely used in epidemiologic and clinical investigations (GL = GI x quantity of serving)
• Dietary Fiber:

  • Certain types of fiber protect against the development of type 2 diabetes
  • Soluble fiber inhibits macronutrient absorption, reduces postprandial glucose responses, and influences blood lipids beneficially
  • Primarily insoluble fiber is associated with reduced diabetes risk
• High Fructose Corn Syrup:

  • Attracts attention as a potential risk factor for insulin resistance and increased risk of type 2 diabetes
  • Cheaper, sweeter, and more quickly absorbed compared to regular sugar
  • Consuming high levels of fructose from high fructose corn syrup can increase insulin resistance and decrease insulin sensitivity
• Ethnic Disparities in Type 2 Diabetes:

  • Type 2 diabetes disproportionately affects Asians, Hispanics, Native Americans, Pacific Islanders, and African Americans
  • Asians have a high risk for developing type 2 diabetes at relatively low levels of body mass due to body composition and distribution of body fat
• Metabolic Syndrome:

  • Symptoms include abdominal obesity, abnormal cholesterol levels, hypertension, insulin resistance, and a pro-inflammatory state
  • Clinical diagnosis is made when any three of these conditions exist in the same individual
• Other Approaches to Prevention:

  • Sustained glucose control is essential to prevent dangerous episodes of hyperglycemia and hypoglycemia
  • Weight loss in overweight and obese diabetic patients reduces insulin resistance
  • Regular examinations are critical to prevent complications such as vision loss, foot issues, and other health risks
• All living things contain the molecules of life and include four macromolecules:

  1. Carbohydrates

  2. Proteins

  3. Lipids

  4. Nucleic acids
• Examples of each macromolecule:

  • Carbohydrates: glucose, cellulose
  • Proteins: enzymes, antibodies
  • Lipids: fats, phospholipids
  • Nucleic acids: DNA, RNA
• All living things are composed of cells

  • Cells are the smallest units of life
  • All cells arise from preexisting cells
• Living things grow and are capable of reproduction

  • Stem cells are the body's raw materials, from which all other cells with specialized functions are generated
  • Under the right conditions, stem cells divide to form more cells called daughter cells
• Living things use energy and raw materials to carry out metabolism

  • Metabolism refers to all of the chemical reactions that occur within the cells of living things
  • Basal Metabolic Rate (BMR) is the number of calories burned as the body performs basic life-sustaining functions
• All living things respond to their environment

  • Stimulus is a thing or event that evokes a specific functional reaction in an organ or tissue
• All living things maintain homeostasis

  • Homeostasis is the relatively constant and self-correcting internal environment of a living organism
• Organisms have adaptive traits that allow them to survive and reproduce

  • Populations will ultimately evolve
  • Bipedalism is a major type of locomotion involving movement on two feet
• Scientists organize living organisms in a system that demonstrates evolutionary relationships

  • Organisms with the greatest similarity are grouped together
  • Several classification systems have been proposed, with the latest including three domains
• The Scientific Method is a process used to design and perform experiments

  • Observation, hypothesis, prediction, experiment, and conclusion are key steps
  • Observation is the first step in research to guide the study
  • Hypothesis is a proposed explanation based on limited evidence
  • Prediction is a specific belief about the scientific idea
  • Experiment accurately tests the hypothesis
  • Results and conclusions are often published in scientific research papers
• Experiments with human participants require informed consent

  • Experiments are first tested on laboratory animals before human trials
  • Informed consent is required from all human participants in clinical trials