BIOL 1203 Week 1 PDF

BIOL-1203 WEEK 1 Units Topics 1 Endocrine System Lab Topic 1 Endocrine System M. Salomon Winter 2025 BIOL-1203 1 REVIEW: NEGATIVE FEEDBACK...

BIOL-1203 WEEK 1 Units Topics 1 Endocrine System Lab Topic 1 Endocrine System M. Salomon Winter 2025 BIOL-1203 1 REVIEW: NEGATIVE FEEDBACK SYSTEMS Stimulus Change Receptors Return to Control centre homeostasis? Effectors Response BIOL-1203 2 REVIEW: NEGATIVE FEEDBACK SYSTEMS WHAT IS THE MAIN GOAL? Stimulus Stimulus disrupts homeostasis by… Change …causing a change in your body Receptors Receptors detect change Feedback loop compares Nervous/chemical signal response to change: Brain processes information & determine if Return to Control centre directs a response body has homeostasis? returned to Nervous/chemical signal homeostatic levels Effectors Effectors cause a response Response Overall response to stimulus BIOL-1203 3 CHEMICAL MESSENGERS IN BODY Blood vessel Response Endocrine signaling Response Paracrine signaling Response Autocrine signaling Synapse Response Synaptic signaling Blood vessel Response Neuroendocrine signaling BIOL-1203 4  HOMEOSTATIC PATHWAYS BRAIN Hypothalamus Hypothalamus Endocrine system Nervous system (mostly ANS) Hormones Nerve impulses Neurotransmitters Slow, enduring Fast, short-term effects effects BIOL-1203 5  ENDOCRINE SYSTEM GENERAL MECHANISM - Hormones - Change in blood Endocrine Hormone Target chemical levels cell Response via blood/lymph cell(s) - Nervous system vessels Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Polypeptides Steroids Types of hormones Peptides Proteins Amino acid derivatives Steroids Insulin Cortisol Amines BIOL-1203 6 Epinephrine Thyroxine ENDOCRINE VS. NERVOUS PATHWAYS BIOL-1203 7 Note: the word “everywhere” is used a little too loosely in this diagram.  TYPES OF GLANDS Exocrine glands Endocrine glands Produce & secrete substances onto surface Produce & secrete hormones directly into of epithelium (skin or body cavity) via ducts. surrounding tissue fluid without using ducts; hormones enter blood or lymph. Examples: - Sweat glands Examples: - Oil glands - Pituitary gland - Salivary glands - Adrenal glands - Mammary glands - Gonads - Gastric glands - Pancreas (Islets of Langerhans) BIOL-1203 8 MAIN ENDOCRINE GLANDS & TISSUES Major endocrine glands: Hypothalamus Pineal gland Pituitary gland Organs containing endocrine cells: Thyroid gland Thymus Parathyroid glands (behind thyroid) Heart Liver Adrenal glands (atop kidneys) Stomach Pancreas Kidneys Small Ovaries (female) intestine Testes (male) BIOL-1203 9 SOME FUNCTIONS OF HORMONES Function Example Reproduction Estrogen from ovaries regulate female menstrual cycle Growth & development Thyroid hormones affect the rate of development of various structures in the body Metabolism Glucagon from pancreas increases blood glucose levels Stimulate endocrine TSH from the anterior pituitary gland stimulates the glands secretion of thyroid hormones Stimulate exocrine Prolactin from the anterior pituitary gland stimulates lactation glands in breasts Activation of muscle or Epinephrine from adrenal glands increase the heart rate nervous tissue Immunity Thymus hormones regulate the development of T lymphocytes BIOL-1203 10 HYPOTHALAMUS & PITUITARY GLAND GENERAL ANATOMY Hypothalamus Pituitary gland Hypothalamus Infundibulum (connecting stalk) Posterior lobe of Anterior lobe of Pituitary gland Pituitary gland BIOL-1203 11 Note: the pituitary gland is also known as the hypophysis.  POSTERIOR PITUITARY GLAND Hypothalamus Neurosecretory cells Axons Hormone Posterior Pituitary Blood capillaries HORMONE ADH Oxytocin TARGET Kidney Mammary glands, tubules uterine muscles BIOL-1203 12  POSTERIOR PITUITARY GLAND ANTIDIURETIC HORMONE (ADH) Actions Hypothalamus Hypothalamus generates thirst  H2O permeability & Osmoreceptors in hypothalamus reabsorption in renal tubules trigger release of ADH (i.e. DCT & Collecting duct) Posterior Main effects pituitary DCT gland  Volume of urine  Urine concentration ADH  Blood volume Stimulus causes Drink Collecting ↑ H2O  Blood osmolarity ↑ Blood osmolarity duct reabsorption water ADH hyposecretion Diabetes insipidus Possible cause: Damaged hypothalamus Feedback loop Response: Symptoms: ↓ Blood osmolarity Polyuria, polydipsia BIOL-1203 13  POSTERIOR PITUITARY GLAND OXYTOCIN Stimulus Suckling infant stimulates mechanoreceptors in nipples Sensory neuron Hypothalamus/ Posterior pituitary Positive feedback Neurosecretory cell OXYTOCIN Blood vessel Target cells Smooth muscles in breasts contract Response Milk release (let-down reflex) BIOL-1203 14  ANTERIOR PITUITARY GLAND Neurosecretory cells Hypothalamus HYPOTHALAMIC Hypophyseal portal system RELEASING & INHIBITING HORMONES (blood capillaries & veins) Endocrine cells of Anterior Pituitary PITUITARY HORMONES HORMONE FSH & LH TSH ACTH Prolactin GH TARGET Testes or Thyroid Adrenal Mammary Liver, bones, Melanocytes ovaries cortex glands other tissues BIOL-1203 15  ANTERIOR PITUITARY GLAND HORMONAL CONTROL Hypothalamic hormone Anterior pituitary Target Hormone production hormone affected in the target Growth hormone releasing Growth hormone Various n/a hormone (GHRH) (GH) tissues Thyroid-stimulating hormone Thyroid-stimulating Thyroid Thyroxine/Triiodothyronine releasing hormone (TRH) hormone (TSH) gland Calcitonin Adrenocorticotropic hormone Adrenocorticotropic Adrenal Corticosteroids releasing hormone (ACTHRH) hormone (ACTH) cortex Gonadotropin releasing Follicle-stimulating Ovaries Estrogens hormone (GnRH) hormone (FSH) Testes n/a Lutenizing hormone Ovaries Estrogens, progesterone (LH) Testes Androgens Prolactin inhibiting hormone Prolactin Mammary n/a (PIH) glands Prolactin releasing factor (PRF) BIOL-1203 16  ANTERIOR PITUITARY GLAND GROWTH HORMONE Hypothalamus Feedback Inhibits GHRH release secretes GHRH & GHIH Stimulates GHIH release Anterior pituitary Inhibits GH synthesis & release GH Growth-promoting Metabolic actions actions Liver & other tissues Produce Insulin-like growth factors (IGFs) Effects Effects Fat Carbohydrate Skeletal Extraskeletal metabolism metabolism Increased cartilage Increased protein Increased Increased blood formation & synthesis, and cell fat breakdown glucose skeletal growth growth & proliferation & release BIOL-1203 17  GH-RELATED DISORDERS Disorder Disorder name Main symptoms Hyposecretion Pituitary dwarfism Slow growth of long bones during childhood Early epiphyseal plate closure Hyposecretion Simmonds’ Decrease in muscle mass, during adulthood disease weakness Hypersecretion Gigantism Excessive long-bone growth during childhood Hypersecretion Acromegaly Overgrowth of certain bones during adulthood (e.g. hands, feet, face) BIOL-1203 18  THYROID GLAND GENERAL ANATOMY Hyoid bone Thyroid cartilage of larynx Pyramidal lobe Internal jugular vein Left lateral lobe Right lateral lobe Common carotid artery Isthmus Trachea Sternum (anterior view) BIOL-1203 19  THYROID GLAND HORMONE PRODUCTION Thyroid follicles Produces Calcitonin Parafollicular cell Follicular cell Produces thyroid hormones from Thyroglobulin and Iodine: - Tyroxine (T4) - Triiodothyronine (T3) Colloid Contains Thyroglobulins and Iodine BIOL-1203 20  THYROID HORMONES Tyroxine (T4) & Triiodothyronine (T3) Regulatory mechanism Derived from tyrosine (amino acid) Hypothalamus Produced by follicular cells Increase metabolic rate TRH Promote tissue growth & development Anterior pituitary Maintain body temperature (increase) TSH Thyroid gland Thyroid hormones Target cells BIOL-1203 21  THYROID HORMONE DISORDERS Disorder Disorder name Main symptoms Hypersecretion during Graves’ disease Increased metabolic rate, weight loss, childhood or (autoimmune) eye protrusion, sweating, goiter adulthood Hyposecretion (severe) Cretinism Mental & physical retardation during childhood Hyposecretion during Myxedema Decreased metabolic rate, edema, adulthood weakness, sensitivity to cold, lethargy Hyposecretion due to Goiter Enlarged thyroid & myxedema lack of iodine in diet symptoms BIOL-1203 22  CALCITONIN Structure Function Polypeptide hormone Involved in calcium homeostasis Produced by parafollicular cells Target cells in skeleton Decreases Ca2+ blood levels: - Inhibits bone resorption by osteoclasts - Promotes Ca2+ uptake into bones BIOL-1203 23  CALCIUM HOMEOSTASIS ROLE OF THYROID GLAND High Ca2+ levels in blood  Calcitonin release Feedback loop from Thyroid gland BONES:  Ca2+ uptake  Osteoclast activity  Ca2+ levels in blood BIOL-1203 24  PARATHYROID GLANDS GENERAL ANATOMY (posterior view) Parathyroid hormone (PTH) - Produced by parathyroid cells - Protein hormone Thyroid gland Parathyroid glands (4) Esophagus Trachea BIOL-1203 25  CALCIUM HOMEOSTASIS ROLE OF PARATHYROID GLAND Hypocalcemia (low blood Ca2+) PTH release from parathyroid glands Feedback loop Osteoclast activity Ca2+ reabsorption Activation of in bone causes Ca2+ in kidney tubule vitamin D by kidney & PO43- release into blood Ca2+ absorption from food in small intestine Ca2+ in blood BIOL-1203 26  PARATHYROID GLANDS PARATHYROID HORMONE (PTH) Effects PTH disorders Calcium homeostasis Hyperparathyroidism (rare) Increases Ca2+ blood levels by: Bone demineralization, causing bone - Stimulating osteoclasts to resorb bone & deformation & softening release Ca2+ from bone (this also increases PO43- blood levels) Hypoparathyroidism Neuronal over-excitation, causing muscle - Enhancing reabsorption of Ca2+ by kidneys twitching & convulsions - Promoting absorption of Ca2+ by intestinal endothelium (via activation of vitamin D) BIOL-1203 27  PANCREATIC ENDOCRINE TISSUE Pancreatic tissue Abdominal aorta Pancreatic islet Duodenum (islet of Langerhans) exocrine acinar cells  cell  cell BIOL-1203 28  PANCREAS MAIN FUNCTIONS Function Secretion Substances Digestion Pancreatic juices Digestive enzymes (as an exocrine gland) Bicarbonate Metabolism Glucose-regulating Insulin (as an endocrine gland) hormones Glucagon BIOL-1203 29 BLOOD GLUCOSE HOMEOSTASIS HORMONAL ACTIONS Hormone Structure Effects Insulin Small protein Promotes: secreted by  cells - Glucose uptake by tissue cells - Glycogenogenesis Inhibits: - Glycogenolysis - Gluconeogenesis Glucagon Polypeptide Promotes: secreted by  cells - Glycogenolysis - Gluconeogenesis BIOL-1203 30 BLOOD GLUCOSE HOMEOSTASIS DIABETES MELLITUS Types Description Typical symptoms Type I Autoimmune disorder Polyuria, glucosuria, ketonuria, causing the destruction of polydipsia, polyphagia  cells Type II Insulin resistance or (most common) deficiency BIOL-1203 31 BLOOD GLUCOSE HOMEOSTASIS Stimulates glucose uptake by cells Insulin Tissue cells Stimulates glycogen Pancreatic islets: synthesis  cells Glucose Glycogen Blood glucose Liver falls to normal range  Blood glucose level (e.g. after eating) BALANCE: Normal blood glucose level  Blood Blood glucose glucose level rises to normal (e.g. after fasting) range Pancreas islets: Liver  cells Glucose Glycogen Stimulates glycogen breakdown Glucagon BIOL-1203 32 Note: mistake in Marieb & Hoehn textbook diagram.  ADRENAL GLANDS HORMONE PRODUCTION Capsule Hormones secreted Aldosterone (a mineralocorticoid) Adrenal gland Cortex Corticosteroids Medulla Cortisol Cortex (a glucocorticoid) & Androgens Kidney (a gonadocorticoid) Medulla Epinephrine (adrenaline) & Norepinephrine Photomicrograph BIOL-1203 33  ADRENAL HORMONES Site of production Hormone type Hormone Adrenal cortex Mineralocorticoid Aldosterone (steroid) Glucocorticoid Cortisol (most abundant) (steroid) Corticosterone Cortisone Gonadocorticoid Dehydroepiandrosterone (DHEA) (steroid) Adrenal medulla Catecholamine Epinephrine (amino acid derivative) Norepinephrine BIOL-1203 34  ADRENAL HORMONES BIOL-1203 35  ROLE OF ALDOSTERONE ↑ Na+ reabsorption, Response: Actions then H2O ↑ Blood pressure & Feedback loop  Reabsorption of Na+ (& H2O) Aldosterone volume in renal tubules (i.e. DCT & Collecting duct) Stimulus causes Arterioles  Secretion of K+ & H+ constrict ↓ Blood pressure or Adrenal gland blood volume into DCT & Collecting duct Main effects DCT Angiotensin II  Volume of urine  Blood volume & pressure  [Na+] in blood Angiotensin I Sensors in ↑ [K+] in blood & stress (via JGA detect Renin ACTH) may also cause the change Angiotensinogen aldosterone release. Juxtaglomerular apparatus (JGA) Liver BIOL-1203 36  STRESS RESPONSE Short-term stress Stress Prolonged stress (alarm response) (resistance response) Nerve impulses Hypothalamus ACTHRH Spinal cord Anterior pituitary Sympathetic To target via blood fibers Adrenal cortex Adrenal medulla ACTH Epinephrine & Mineralocorticoids Glucocorticoids Norepinephrine Effects Effects - Increased heart rate & blood pressure - Dilation of bronchioles - Kidneys retain Na+ & H2O - Proteins & fats converted to - Liver converts glycogen to glucose & releases glucose - Increased blood volume & glucose or broken down for into blood blood pressure energy - Change in blood flow, reducing activity of digestive system - Increased blood glucose & urine output - Partial suppression of immune - Increased metabolic rate system BIOL-1203 37  ADRENAL DISORDERS RELATED TO GLUCOCORTICOIDS Disorder Disorder name Main symptoms Hyposecretion Addison’s disease Hypoglycemia, loss of weight, of glucocorticoids & weakness, hypotension mineralocorticoids Hypersecretion Cushing’s syndrome Hyperglycemia, loss of muscle of glucocorticoids proteins, hypertension, H2O/salt retention, redistribution of body fat (to abdomen & back of neck), bruising BEFORE AFTER BIOL-1203 38 ORGANS WITH ENDOCRINE TISSUE SECONDARY ENDOCRINE FUNCTIONS Organs Hormones produced (non-exhaustive list) Gonads - Ovaries Estrogens - Testes Androgens Digestive organs - Duodenum Secretin, CCK - Stomach Gastrin Placenta hCG, estrogens, progesterone Thymus Thymosins Kidneys Erythropoietin Heart Atrial natriuretic peptide (ANP) Adipose tissue Leptin BIOL-1203 39  GONADAL HORMONES Ovary Testis Hormone Function Hormone Function Estrogens Promote development of Androgens Promote development of (e.g. estradiol) primary & secondary (e.g. primary & secondary male female sexual testosterone) sexual characteristics characteristics Inhibin Inhibit FSH production by Progesterone Regulate uterine cycle, anterior pituitary gland support pregnancy, promote breast milk production Inhibin Inhibit FSH production by anterior pituitary gland BIOL-1203 40  PLACENTA ENDOCRINE FUNCTION Placenta Hormone Function Human chorionic Maintain receptive state of gonadotropin uterus for implantation; Uterine wall (hCG) stimulate production of sex hormones Estrogens Promote growth of uterine lining; support pregnancy; Progesterone promote growth of mammary glands BIOL-1203 41  DIGESTIVE ORGANS ENDOCRINE FUNCTION Organ location (cells) Hormone Function Stomach mucosa Gastrin Promotes gastric juice secretion & (G cells) gastric mobility Duodenal mucosa Secretin Promote pancreatic juice & bile (S cells vs. CCK cells) CCK secretion Stomach Duodenum BIOL-1203 42  THYMUS ENDOCRINE FUNCTION Hormone Function Thymus Thymosins Promote development & maturation of T lymphocytes; Thymulin Help mount immune Right responses lung Left Thymopoietins lung Diaphragm BIOL-1203 43  PINEAL GLAND ENDOCRINE FUNCTION Hormone Functions Melatonin Set circadian rhythms (e.g. appetite, sleep); Antioxidant that protects CNS Thalamus Hypothalamus Pineal gland BIOL-1203 44  PROSTAGLANDINS LOCAL SIGNALLING Local signal Structure & function Prostaglandins - Lipids - Produced in all tissues - Paracrine or autocrine signals (not hormones) - Regulate many processes (e.g. inflammation, digestion, pain, blood pressure) BIOL-1203 45