Topic 8: Endocrine System

• What is the endocrine system primarily composed of?

  Specialized organs called endocrine glands
• What does endocrinology study?

  The endocrine system and its disorders
• What are the main functions of the endocrine system?

  • Co-ordination
  • Homeostasis
  • Glandular secretion
  • Metabolism
  • Behaviour
  • Growth and development
  • Physical appearance
  • Reproduction
  • Digestion
  • Circadian rhythm
  • Body fluids
  • Immune response
  • Mood and emotions
  • Hunger
• What are hormones?

  Chemical messengers transported by the bloodstream
• How do lipid-soluble hormones circulate in the body?

  Bound to transport proteins

  
• How do water-soluble hormones circulate in the body?

  Freely in the plasma

  
• Where do lipid-soluble hormones bind in target cells?

  To receptors within target cells

  
• Where do water-soluble hormones bind in target cells?

  To receptors on the exterior surface

  
• What factors influence how a target cell responds to a hormone?

  The hormone's concentration, receptors, and other hormones
• What is the synergistic effect in hormone action?

  When multiple hormones work together
• What is the antagonistic effect in hormone action?

  When one hormone opposes the action of another
• How are hormones secreted?

  In short bursts when needed
• What regulates hormone secretion?

  Signals from the nervous system and chemical changes
• What is negative feedback in hormone secretion?

  Increased hormone levels inhibit further release

  
• What is positive feedback in hormone secretion?

  Increased hormone levels stimulate further release

  
• What does the hypothalamus regulate?

  Primitive functions like water balance and thermoregulation
• What processes does the hypothalamus help stimulate or inhibit?

  • Heart rate and blood pressure
  • Body temperature
  • Fluid and electrolyte balance
  • Appetite and body weight
  • Glandular secretions of the stomach and intestines
  • Production of substances influencing the pituitary gland
  • Sleep cycles

  
• What is the pituitary gland also known as?

  Hypophysis
• What hormones are produced by the anterior pituitary lobe?

  TSH, FSH, LH, ACTH, hGH, PRL

  
• What does somatostatin inhibit?

  Secretion of growth hormone and TSH

  
• What are the actions of anterior pituitary hormones?

  • Growth hormone (GH): Stimulates growth and metabolism
  • Thyroid-stimulating hormone (TSH): Stimulates thyroid hormone secretion
  • Follicle-stimulating hormone (FSH): Stimulates oocyte development and sperm production
  • Luteinizing hormone (LH): Stimulates sex hormone secretion and ovulation
  • Prolactin (PRL): Stimulates milk production
  • Adrenocorticotropic hormone (ACTH): Stimulates glucocorticoid secretion

  
• What does oxytocin stimulate?

  Contraction of the uterus during childbirth

  
• What does antidiuretic hormone (ADH) do?

  Conserves body water and raises blood pressure
• What are the functions of the thyroid gland?

  • Regulates metabolism
  • Increases basal metabolic rate
  • Promotes gluconeogenesis and glycogenolysis
  • Stimulates protein synthesis and lipogenesis
  • Involved in thermogenesis

  
• What shape is the thyroid gland?

  Butterfly-shaped

  
• What is the role of parafollicular cells in the thyroid gland?

  Secrete calcitonin

  
• What is the process of thyroid hormone synthesis initiated by?

  Recognition of TSH by TSH-receptors
• What does parathyroid hormone (PTH) do?

  Increases blood calcium levels

  
• What are the functions of the adrenal cortex?

  • Produces mineralocorticoids like aldosterone
  • Regulates sodium retention and potassium excretion
  • Produces glucocorticoids that regulate glucose metabolism
• What is the role of the pineal gland?

  • Synthesizes melatonin from serotonin
  • Synchronizes physiological functions with circadian rhythms
  • May influence seasonal affective disorder (SAD)
• What is the role of the thymus in the body?

  • Maturation of T cells for immune defense
  • Secretes hormones that stimulate lymphatic organ development
• What are the metabolic processes increased by thyroid hormones?

  • Basal Metabolic Rate
  • Gluconeogenesis
  • Glycogenolysis
  • Protein synthesis
  • Lipogenesis
  • Thermogenesis
• What are the effects of growth hormone (GH) on the body?

  • Stimulates growth of body cells
  • Promotes protein synthesis and tissue repair
  • Influences bone growth and remodeling

  
• What does the parathyroid gland do?

  It eases bone resorption
• Where is the thyroid gland located?

  In the neck
• What is the function of the esophagus?

  It transports food to the stomach
• What is the trachea's role in the body?

  It conducts air to the lungs
• What is the pharynx?

  A muscular tube for food and air
• What do parathyroid glands regulate?

  Blood calcium levels

  
• What type of tissue is adipose tissue?

  Connective tissue