Module 1 - Endocrine System Flashcards
Functions of System
Regulates blood composition and volume
Manage stressors
Regulates growth and development
Controls reproductive processes
Balances metabolism and energy
Aid immune function
Contracts muscles and gland secretion
Components
Hypothalamus
Pituitary Gland - Anterior & Posterior
Thyroid gland
Parathyroid gland
Thymus
Adrenal glands
Pancreas
Gonads - ovaries & testes
Exocrine glands
Exocrine – DUCTS – release their produce into ducts, bringing products to target or body surface – lumen of organ
Sweat
Milk
Digestive enzymes
Mucous – protects respiratory system
Endocrine glands
Endocrine – DUCTLESS – release products (hormones) into interstitial fluid/bloodstream – by diffusion
Maintains body functions – growth, metabolism, and repo
Up-regulation
Up-regulation – less hormones, # of receptors increases
Down-regulation
Down-regulation – Increased hormone, # of receptors will decrease to avoid over stim
Lipid Solubility
Lipid Solubility
Receptors – inside cell – fats pass through the bilayer of a cell
Needs carrier protein when exposed to water in bloodstream
Binds to receptor in cytosol or nucleus
Alter gene expression – turn on or off a gene
Types:
Steroid
Thyroid
Nitric ox- ide – relaxes blood vessels, widens increasing blood flow, lowering BP
Water Solubility
Water Solubility
Floats in water of blood
Cytoplasmic response and gene expression
Exocytosis to exit cell to go into bloodstream
First Messenger - Receptors on surface of cell – hormone binds
Activates G protein
Secondary messenger – G protein binds to Adenylyl cyclase inside to communicate response
Adenylyl w/ ATP = CAMP
CAMP activates protein kinase
Protein kinase are enzymes that modify proteins within a cell – activates or inactivates processes in cell
Types:
Single amino acid
Epinephrine and Norepinephrine
Peptides:
Antidiuretic hormones (ADH)
Oxytocin
Proteins:
Insulin
Growth hormone
Hormone Secretion
Hormone Secretion
Maintains homeostasis
Prevents overproduction or underproduction – disorder can occur
Controlled by:
Signals of nervous system
Chemical changes in blood
Other hormones
Negative feedback example
Negative feedback example
1) Imbalance – low blood conc. of glucocorticoids – senses tell
2) Hormone release – hypo releases CRH
3) Correction – CRH starts cascade – triggers adrenal glands to release glucocorticoid into blood – conc. goes up
4) Negative feedback – sensors tell hypo to stop release of CRN
5) Homeostasis
Hypothalamus
Hypothalamus – master regulator – link between nervous and endocrine systems – in diencephalon in brain – inferior and anterior to thalamus
Pituitary Gland – Hypophysis
Pituitary Gland – Hypophysis
Reacts to messages from hypo – divided into anterior and posterior lobes – in hypophyseal fossa of sphenoid bone
Anterior Pituitary Gland – adenohypophysis
controlled by releasing or inhibiting hormone from hypothalamus – produces 7 hormones that influence homeostasis
Hypophyseal portal system
Human growth hormone (hGH)
Thyroid-stimulating hormone (TSH)
Follicle-stimulating hormone (FSH)
Luteinizing Hormone (LH)
Prolactin (PRL)
Adrenocorticotrophic hormone (ACTH)
Melanocyte-stimulating hormone (MSH)
Hypophyseal portal system
Hypophyseal portal system – blood supply – nervous tissue in hypothalamus communicates so anterior gland produces hormones – diffuses in to blood supply in gland – separate from body circulation
Human growth hormone (hGH)
Human growth hormone (hGH) – promotes protein synthesis (to build) – triggers liver to secretes insulin-like growth factors after breakdown of glycogen into glucose – stimulates growth and regulates metabolism – regulated by GHRH sent by hypothalamus
Thyroid-stimulating hormone (TSH)
Thyroid-stimulating hormone (TSH) – regulates thyroid gland – stimulated by thyrotropin-releasing hormone (TRH) from hypothalamus
Follicle-stimulating hormone (FSH)
Follicle-stimulating hormone (FSH) – females: initiates follicle development and estrogen secretion in ovaries – males: stims sperm production in testes – type of Gonadotropin
Luteinizing Hormone (LH)
Luteinizing Hormone (LH) – females; stims estrogen for ovulation and secretion of progesterone – males; stims testes to secrete testosterone – type of Gonadotropin
Prolactin (PRL)
Prolactin (PRL) – milk production – no stim factor – not ejection – dopamine inhibits
Adrenocorticotrophic hormone (ACTH)
Adrenocorticotrophic hormone (ACTH) – produces and controls glucocorticoids in adrenal glands – stim.ed by Corticotropin
Melanocyte-stimulating hormone (MSH)
Melanocyte-stimulating hormone (MSH) – skin pigmentation
Posterior Pituitary Gland – neurohypophysis
Posterior Pituitary Gland – neurohypophysis
No production
Stores and releases 2 hormones made in hypothalamus
Nervous tissue – axons and terminal – communication with hypothalamus to release or inhibit hormones stored
Oxytocin (OT)
Antidiuretic hormone (ADH)
Oxytocin (OT)
Oxytocin (OT) – contracts uterus with positive feedback loop in childbirth – controls ejection of milk (let-down)
Antidiuretic hormone (ADH)
Antidiuretic hormone (ADH) – maintains blood osmolarity by controlling water balance – stims reabsorption by kidneys
Thyroid Gland
Thyroid Gland
located below larynx around trachea
Right and left lobes
Mains a level of iodine within tissue
Composed of thyroid follicles – secrete thyroxine (T4) and triiodothyronine (T3) & parafollicular cells – secrete Calcitonin (CT)
Thyroid hormones – T4 and T3
Calcitonin (CT)
Calcitonin (CT)
Secretion controlled by level of iodine in gland – influenced by negative feedback with Hypo and ant pituitary gland
Calcitonin – lowers blood calcium levels – lower conct. = secretion
Thyroid hormones – T4 and T3
Thyroid hormones – T4 and T3 – regulate oxygen use, metabolic rate, cellular metabolism, growth and development – produced in colloid of thyroid cell tissue
Thyroid hormones – T4 and T3
Steps of production and release
Thyroid hormones – T4 and T3
Steps of production and release:
1) iodine taken up by body becomes Iodide by digestive tract – travels in blood, transported into basal cells of thyroid then diffuses into colloid
2) thyroglobulin synthesis in colloid
3) iodide oxidizes – loses positive charge – by hydroperoxide in colloid
4) Iodide and thyroglobulin bind together – with help of enzyme
5) Produces:
T1 – Mono-iodothyronine (MIT)
MIT + DIT = T3
T2 – Di-iodothyronine (DIT)
DIT X 2 = T4
6) Pinocytosis - secretion from thyroid basal cells into bloodstream
7) Transport in blood
Hyperthyroidism
Hyperthyroidism – overproduction of T4 & T3 = over stim of thyroid gland – Cancer, growths and graves disease
Hypothyroidism
Hypothyroidism – underproduction of T4 & T3 – under stim of thyroid gland – destroys tissues of gland
Parathyroid Gland
Parathyroid Gland
Located on posterior surface of thyroid gland
Superior and inferior parathyroid glands
Produces parathyroid hormone (PTH)
Works in negative feedback system
Increases blood calcium levels
Decreases blood phosphate levels Calcitonin opposes PTH
Parathyroid Hormone (PTH)
Parathyroid Hormone (PTH) – regulates Ca+ and P levels
Increases blood calcium levels
Activates osteoclasts – releases calcium by breaking down bones
Inhibits osteoblasts
Reabsorption in Kidneys
Absorbs from digestive tract
Decreases blood phosphate levels
Vitamin D – PTH puts more phosphate into urine so vitamin D will increase phosphate reabsorption b/c we need for ATP
Calcitonin opposes PTH
Pancreas
Pancreas
Exocrine and endocrine gland
Flat organ posterior & inferior to stomach
Managers blood glucose levels – normal: 70-110mg/dL
Pancreatic islets / islets of Langerhans – specialized clusters of cells – endocrine
Secrets bile for digestion
Acini – clusters of cells – enzyme-producing – exocrine
Pancreatic islets
Pancreatic islets / islets of Langerhans – specialized clusters of cells – endocrine
Alpha cells – glucagon
Beta cells – insulin
Delta cells – somatostatin – inhibits insulin and glucagon release
PP cells – pancreatic polypeptide – controls appetite
Alpha cells
Alpha cells – glucagon
Beta cells
Beta cells – insulin
Delta cells
Delta cells – somatostatin – inhibits insulin and glucagon release
PP cells
PP cells – pancreatic polypeptide – controls appetite
Hyperglycemia
Hyperglycemia (high BG) – NEEDS INSULIN to decrease
Triggers uptake of glucose from blood
Glycogenesis
Proteogenic
Lipogenesis
Glycogenesis
Liver stores glucose as glycogen - Glycogenesis
Proteogenic
Stops amino acids & free glycerol to glucose – Proteogenic – builds up proteins
Lipogenesis
Stores extra as fat – Lipogenesis
Hypoglycemia
Hypoglycemia (low BG) – NEEDS GLUCAGON to increase
Stops glucose uptake from blood
Lipolysis
Glycogenolysis
Gluconeogenesis
Lipolysis
Breaks down fat - Lipolysis
Glycogenolysis
Stims liver to breakdown glycogen into glucose – Glycogenolysis
Gluconeogenesis
Stims liver to take in amino acids and free glycerol into glucose – Gluconeogenesis
Adrenal Glands
Adrenal Glands
Superior to kidneys
Consist of outer cortex and inner medulla
Controlled by hypothalamus and anterior pituitary gland
“TERONE” – cholesterol – lipid soluble – steroids
Outer cortex
Outer cortex – 85% - divided into zones each with different hormones
Outer – Zona Glomerulosa – mineralocorticoids - ALDOSTERONE
Middle – Zona Fasciculate – glucocorticoids – CORTISOL
Inner – Zona Reticularis – Androgens
Outer – Zona Glomerulosa
Outer – Zona Glomerulosa – mineralocorticoids - ALDOSTERONE
Fluid, electrolyte, and mineral balance
effects blood pressure and volume
increase Na+ and H20 reabsorption
decrease P reabsorption
renin-angiotensin pathway – communication pathway with kidneys
Middle – Zona Fasciculate
Middle – Zona Fasciculate – glucocorticoids – CORTISOL
Regulate glucose metabolism – catabolic
Breaks down proteins
Forms glucose
Lipolysis – fat breakdown
Resistance to stress
Anti-inflammatory
Depression of immune response
Controlled anterior pituitary
Corticotropin-releasing hormone (CRH)
Adrenocorticotropic hormone (ACTH)
Inner – Zona Reticularis
Inner – Zona Reticularis – Androgens – Dehydroepiandrosterone
Steroid sex hormones
ACTH converted into testosterone or estrogen
Medulla
Medulla – Chromaffin – neuroendocrine cells – ganglion
Epinephrine and norepinephrine
Produce stress responses – fast action
Direct innervations from ANS – preganglionic fiber synapse
Large blood vessels – quick distribution of hormones
Gonads
Gonads – Ovaries and Testes
Produce gametes/sperm and oocytes/eggs
Controlled by pituitary gland – FSH and LH
Aromatization – Adam to Eve – get female hormones from male hormones - FSH
Ovaries – Pelvic cavity
Testes – inside scrotum
Ovaries
Ovaries – Pelvic cavity
Estrogen and progesterone
Development
Sexual characteristics
Repro cycle
FSH – follicle maturation
LH – ovulation – release ova from follicle
Pregnancy - relaxin
Lactation
Produce inhibin and relaxin
Female FSH
FSH – follicle maturation
Female LH
LH – ovulation – release ova from follicle
Relaxin
maintains pregnancy
Testes
Testes – inside scrotum
Testosterone – LH
Development
Sexual characteristics
FSH – spermatogenesis – creation and maturation of sperm
Produce inhibin – inhibits secretion of FSH – reduces spermatogenesis
Male LH
Testosterone – LH
Male FSH
FSH – spermatogenesis – creation and maturation of sperm
Inhibin
Produce inhibin – inhibits secretion of FSH
Pineal Gland or Epiphysis cerebri
Pineal Gland or Epiphysis cerebri
Posterior to thalamus – attached to roof of third ventricle
Cells:
Pinealocytes – neuroendocrine cells – produce and secretes melatonin
Neuroglia
Postganglionic sympathetic fibres
Internal clock – diurnal rhythms – circadian rhythms
Light sensors in retina stim hypothalamus
Hypothalamus tells pineal gland to secrete melatonin
Released into CSF then passed to bloodstream
Light = wakeup – no melatonin
Dark – drowsy – melatonin
Thymus Gland
Thymus Gland
Medial to lungs and superior to heart
Atrophy with aging
Contain thymocytes – T cells
Secrete immunity hormones – develop and maturation of T cells – white blood cell
Thymosin
Thymic humoral-factor
Thymic factor
Thymopoietin
Cortisol lowers functions of T cells – in stress cortisol spikes – immunity lowers
Thymosin
Thymosin
Immunity hormones – develop and maturation of T cells – white blood cell
Heart
Heart
Atrial natriuretic peptide (ANP) – reduce blood volume, BP, and Na+ concentration
Sensors in atrial walls sense high blood volume or pressure
GI Tract
GI Tract
Eat food – glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1) – stim pancreas to secrete insulin
Gastrin, secretin, and cholecystokinin – aids digestion and buffer acid in stomach
Kidneys
Kidneys
Renin – stimed when blood flow decreases – tells adrenal cortex to release aldosterone
Calcitriol – converted from Vitamin D – helps maintain blood Ca+ levels – aids absorption
Erythropoietin – response to low O2 – stims production of RBC in marrow – increase O2 delivery
Renin
Renin – stimed when blood flow decreases – tells adrenal cortex to release aldosterone
Calcitriol
Calcitriol – converted from Vitamin D – helps maintain blood Ca+ levels – aids absorption
Erythropoietin
Erythropoietin – response to low O2 – stims production of RBC in marrow – increase O2 delivery
Skeleton
Skeleton
FGF23 – produced by bone cells b/c increase blood Vit. D or P – triggers kidneys to release calcitriol & increase P excretion
Osteocalcin – produced by osteoblasts – stim pancreas Beta cells to increase insulin production
Adipose Tissue
Adipose Tissue
Leptin – metabolism and storage of lipids – tells brain we are full
Adiponectin – reduces insulin resistance
Liver
Liver
Insulin-like growth factor-1 – stims growth – specially in bones
Angiotensinogen – increase BP
Thrombopoietin – platelets – increase blood clotting ability
Hepcidin – blocks iron release – stores in for homeostasis
Alarm Reaction – fight or flight
Alarm Reaction – fight or flight
Nerve impulses send from hypothalamus to ANS and adrenal medulla
Release of epinephrine or norepinephrine starts response
Increase circulation
Increased catabolism for energy production
Decrease nonessential activities – ex digestion
Resistance Reaction
Resistance Reaction – shift in energy balance
Hypothalamus sends CRH to anterior pituitary gland
Increase secretion of ACTH
Tells adrenal cortex secrete Glucocorticoids
Accelerate catabolism to make energy to combat stress
Exhaustion
Exhaustion
Results from lots of alarm or resistance reactions
Causes by a loss of P – its been burned up for ATP and glucose production
Adrenals stores of glucocorticoids is used up
Possibly death – severe
Disease
Disease
Interleukin-1 (IL-1) – produces macrophages – stims ACTH
Stims CRH in hypo
Stims ACTH in pituitary gland
If low - lowered immune response
If low – Inhibits release of GH
If low – can’t stim release of prolactin
Stress linked to chronic disease
GI – gastritis, IBS
Heart – hypertension
Resp – asthma
Nervous – migraine headaches, anxiety and depression
