(16) - endorine system
What are the 5 anterior pituitary trophic cells and the hormones they release? CTSLG Came To See Lucy & Gray
1)Corticotrophs - remember adrenal cortex- signal the adrenal cortex to release their hormones 2)Thyrotrophs - signals the thyrogland 3)Somatotrophs - soma means body -- stimulate many cells in your body for growth 4)Lactotrophs - lacto means milk - affects mamillary glands for milk production 5)Gonadotrophs - testes and ovaries - produce hormones that affect those tissues
List the major chemical classes of hormones
1. Amino acid derivatives: thyroid hormones, compounds NE/E/Dopamine (sometimes called catecholamines), and tryptophan derivatives (i.e. melatonin secreted by pineal gland) 2) Peptide hormones- synthesized as prohormones (inactive precursor molecules to be converted into active hormones) 3) Lipid derivatives- built from either fatty acids (eicosanoids-affects enzymatic processes in extracellular fluid) or cholesterol (steroids)
1. List two major types of eicosanoids and discuss their production and functions.
1. leukotrienes: involved in inflammatory responses (allergies) 2. prostaglandins: important to activate neurons for pain/injury to cells
Compare and contrast how the nervous and endocrine systems control body function, with emphasis on the mechanisms by which the controlling signals are transferred through the body and the time course of the response(s) and action(s).
CONTRAST: nervous is faster than endocrine. - neurons - response time is faster and the duration of the effect is immediate/short. release into the synaptic cleft and then bind to a receptor. but they get deactivated pretty quick. - hormones - response time is slower but the duration is longer because its released in spurts. cells release their products into the external fluid around the cell, diffuse into the circulatory system, then travel miles and find its target cell. but more hormone will follow behind to keep going (like adrenaline aka norepinephrine/epinephrine) SIMILAR: want to maintain homeostasis, use similar chem messengers like NE & E, rely on negative feedback and messengers binding to specific receptors
how are amino acid derivative hormones transported in the blood?
Water soluble a.k.a hydrophilic Can float/get off through plasma without needing a binding protein, then binds to a receptor in the cell membranes Exception: T3 and T4 (insoluble hormone) need a transporter called thyroxine-binding-globulin (TBG). T3 and T4 lipid based hormone but because it is attached by TBG (water soluble) it makes it able to interact with blood.
how are peptide derivative hormones transported in the blood?
Water soluble a.k.a hydrophilic When leaving circ.system → gets to target tissues → can't enter cell membrane → binds to extracellular receptor→ which triggers second messenger cascade inside the cell. SMS: water soluble hormone binds receptor → G protein activates → activates Adenylyl Cyclase → grabs molecule of ATP → turn into cAMP → activate protein kinase I.e. GH + Insulin
Explain the mechanism by which a lipid derivative hormone changes the activity of a target cell.
lipid derivative, thus hydrophobic, does not need an extracellular receptor because the cell membrane is made of mostly lipids, so goes right through. - at some point inside, in the cytoplasm or the nucleus, then it will bind to a receptor and form a hormone-receptor complex and change pattern of protein synthesis, which directly affects metabolic rate and structure ** in the nucleus, would change translation/transcription
synaptic
neuron releases neurotransmitter across synapses and binds a receptor on target cell, and excites/inhibits that target cell
direct
one cell connected by gap junctions to another cell and allow them to share their intracellular fluid like ions, etc
Describe the major functions of the endocrine system.
releases chemical messengers for reestablishing homeostasis
define releasing hormone and inhibiting hormone
releasing hormone: stimulates the synthesis/secretion of one or more hormones at the anterior lobe inhibiting hormone: prevents the synthesis/secretion of hormones from the anterior lobe ** remember: hypothalmic nuclei produce releasing/inhibiting hormone. they tell what the pituitary gland to do. it's the master!
paracrine
through ECF -- one cell makes a product that effects the cell nearby ** parachute: put it next to you or on your back
Thyrotropin-RELEASING hormone stimulates which trophic cell?
thyrophs
1. Explain the mechanism by which an amino acid or peptide hormone changes the activity of a target cell.
SECOND MESSENGER SYSTEM -- so the water soluble/polar/charge hormone [first messenger] has to bind to a receptor on that target cell membrane. when that happens, it starts a series of protein changes [second messenger] inside the cell. 1. "first messenger" hormone binds to a receptor 2. G-protein is activated 3. change to concentration of cAMP (adenylate cyclase + ATP=cAMP) or open Ca+ channels (both act as secondary messengers) 4. activate protein kinase which adds phosphates throughout cell --> THUS, accelerating/inhibiting the metabolic (enzyme) activity of a cell ** kinda like a spy mission. i can't get in so i bond with this other person that will go in and do the work for me inside
Growth hormone RELEASING/NHIBITING hormone stimulates which trophic cell?
SOMAtrophs -- growth! ** note that growth/lactin is the only hormones that have releasing/inhibiting
Explain the role of the hypothalamus in the production and release of posterior pituitary hormones.
contains supraoptic & paraventricular nuclei goes to --> posterior pituitary - they bypass the portal circulation. their axons travel down a stock that connects the pituitary to the hypothalmus and go directly to the capillary system of the posterior pituitary. - here, they release oxytocin and antidiuretic hormones that can enter circulation or be stored. ** remember: anterior has RH/IH, posterior only has 2 hormones OXT and ADH
Corticotrophin-RELEASING hormone stimulates which trophic cell?
corticotrophs.
define diabetes mellitus and name its 2 types
diabetes means: excessively high blood glucose (sugar) level that the kidney's can reabsorb them d. 1 -- autoimmune disease; white blood cells are attacking your beta cells in the pancreas. if they do that, you can't make insulin. sugar will stay in your body without insulin. d. 2 (most common) -- result of insulin resistance and obesity; normal beta function but then leads to burnout. insulin resistance - insulin is being secreted but nothing's happening when it binds
1. Explain the difference between an exocrine and endocrine cell [Review Module 4.3 & 4.8].
endocrine: release their secretions into the interstitial fluid (so goes inside the blood) exocrine: release their secretions into ducts that open onto an epithelial surface (so it exits the body) ** pancreas does both
describe T3/T4?
even though its base (tyrosine) is an amino acid which usually means we make a water-soluble molecule, t3 and t4 are not water soluble - they are water-phobic/Lipid derivative --> needs to be covered in a transportor (TBG) ** Analogy: T4 = weak; is the grenade with the pin in and lever depressed. It's a weak hormone T3 = strong; takes off one of the iodines and releasing the lever Changes what the cell is doing very quickly. T4 (the safe one) is what's going around our system. If cells need something that T3 can do, they can just take in T4 and remove the iodine
1. Explain the role of the hypothalamus in the release of anterior pituitary hormones.
has neurosecretory neurons goes to --> anterior pituitary ** portal circulation is a connection between hypothalmus and the anterior pituitary (not posterior!!) RH/IH from the capillary bed of the hypothalmus travels through portal veins and into the anterior pituitary capillaries. now RH/IH can be released to the cells that make up the anterior pituitary and the AP can then respond. capillaries --> veins --> capillaries
What is the root (etymology) of the word hormone
hormon/er - that which sets in motion
Define the terms hormone, endocrine gland, endocrine tissue (organ), and target cell.
hormone: regulate what tissues/cells in those tissues are doing like increasing/decreasing/work endocrine gland: gland that secretes their hormones direclty into the blood endocrine tissue: make up endocrine glands target cell: a cell that contains specific receptors for an chemical messengers
Explain how the endocrine organs relate to other body organs and systems to maintain homeostasis
hormones from endocrine organ will affect other organs? like protein catabolism (break down off aa) for nucleogenesis
Most hormones are produced by glandular cells, released into ______________ fluid, after which they diffuse or are transported into the _______________ system for transport to their target tissue.
interstium fluid (aka the extracellular fluid) circulatory system
pathway for insulin?
Awake and eating → glucose levels go up → beta cells detect and release insulin → binds insulin receptor and starts a second messenger system BETA = INSULIN BI'M SO HUNGRY
Explain the need for binding proteins in circulating blood and the role these proteins play in the regulations of the hormones they transport.
BLOOD has H20 (polar), which won't mix with LIPIDS (nonpolar). they must bind to the protein TBG to interact without being detected LIPIDS can't be transported in the circ. system otherwise
define tropic hormone
"turn on" endocrine glands or support the functions of other organs
hormones released during short-term stress and describe the hormonal actions?
- Epi. -- most dominant -NE (from adrenal medulla) body prepares to deal with stress factor by "fight/flight" response
define gigantism and acromegaly,
- Gigantism (too much hGH as a child): abnormally high bone growth - Acromegaly (too much hGH as an adult) bones get thicker
hormones released during long-term stress and describe the hormonal actions?
- Glucocorticoids aka CORTICOL (most dominant) - GH - E - thyroid hormones mobilize lipids and amino acids to shift tissue metabolism away from glucose to make more glucose available for neurons
Trace pathway for Thyroid-stimulating hormone (TSH),
- Stimulated by: Cold temp - Hypothalamus releases THYROtropin-Releasing Hormone (TRH) -- portal circ. --> binds THYROtrophs - Releases THRYROid Stimulating Hormone (TSH) - Goes to THYROid Gland - Thyroid gland cause follicular cells to make T3 and (mostly) T4 and release into blood through Thyroxine Binding Globulin TBG) - increase metabolism/O2 Consumption
Trace pathway for Human growth hormone (hGH)
- Stimulated by: Growing, sleep, needing more glucose - Growth Hormone Releasing Hormone (GH-RH) -- port cir → finds somatotrophs, -Somatotrophs release Human Growth Hormone (hGH) into systemic circulation (bloodstream) - Goes to liver, creates somatomedins/insulin growth factor [IGFs], goes to muscles which can then make their own SM/IGF - Increases bone and muscle growth (glycogenolysis in liver) ** SM = IGF, they the same thing
Trace pathway for Prolactin (PRL)
- Stimulated by: Pregnancy - Hypothalmus releases ProLACTin Releasing Hormone → port. Circ. → binds LACTotrophs - Releases ProLACTin (PRL) into sys. circ. - Binds to mammary glands - Stimulates development of the gland/milk production ** note: OXYTOCIN needed for ejection of milk
Trace pathway for Luteinizing hormone (LH)
- Stimulated by: Puberty - Hypothalamus releases GONADotropin Releasing Hormone (GnRH) -- portal circ. → binds GONADtrophs - Releases Luteinizing Hormone (LH) into systemic circ. - Binds to leydig cells in testes or theca cells in ovaries - Increase product./secr. of testosterone in M, estrogen for F (testosterone turns into estrogen) * needs SEX-HORMONE BINDING GLOBULIN (SHBG) and ANDROGEN-BINDING protein LEU = determines your LEWK with Test. and Est. she's a THECA woman put lyDIG(ck) in me
Trace pathway for Follicle stimulating hormone (FSH)
- Stimulated by: Puberty - Hypothalamus releases GONADotropin Releasing Hormone (GnRH) --> portal circ. --> binds GONADtrophs - Releases Follicle Stimulating Hormone (FSH) into systemic circ. - Binds to sertoli cells in testes or theca cells in ovaries - Increases Ova maturation or increase sperm #
Trace pathway for Adrenocorticotropic hormone (ACTH)
- Stimulated by: stress (fight/flight) - Hypothalmus releases CORTICOotropin Releasing Hormone (CRH) → port. Circ → binds CORTICOtrophs - Releases AdrenoCORTICOtropic Hormone (ACTH) into sys. Circ. - Because this is a peptide hormone, thus water soluble, binds to receptors on the adrenal cortex - Increases production of GlucoCORTICOids AKA CORTISOL (stress hormone)
Trace pathway for Oxytocin (OXT)
- Stimulated by: stretching of the cervix in child birth and suckling with breast feeding - Posterior pituitary (P.P.) releases OXT into sys. Circ. - Binds cells of the uterus or mammary glands - Allows contraction of smooth muscle for uterus or mammary glands
Trace pathway for Antidiuretic hormone (ADH, a.k.a vasopressin)
- Stimulated by: thirst/dehydration - Paraventricular/supraoptic nuclei of the hypothalamus are stimulated when h2o levels are low - P.P. Releases ADH into systemic circ. - Affects the kidneys → saving water (less h2o excreted from urine) * ADH - think diarrhea. Diuretic is wet and uncontrollable. Body's losing water somehow. So ANTIdiuretic will RETAIN water in the form of urine. So kidneys make less urine when ADH is high.
exhaustion phase
- aldosterone production results in NA+ conservation at the cost of K+ - K+ goes down, neurons and muscle fibers begin to malfunction
what are the water soluble (hydrophilic) hormones?
- amino acid derivatives like melatonin made from tryptophan - peptide hormones like insulin, growth hormone, parathyroid hormone ~they're sALL about the water~ ** water soluble will have to bind to the membranes
resistance phase
- neural tissue must have enough glucose because it's highly demanded - glycogen reserves adequate but depleting - mobilize lipids and a.a., shifting metabolism from glucose so that it can be used by the nervous system ** can only hold up for weeks or months
what is thymosine
- secreted by thymus - stimulates the production of T- Cells ** important part of the immune system
3 stages of stress? ARE u stressed bruv
1) Alarm phase - immediate response to stress factor; 2) Resistance phase - occurs if stress lasts more than a few hours; 3) Exhaustion phase - when R. phase ends; face sickness
describe negative feedback loop for hormone release
1) Hypothalamus produces releasing hormone, telling anterior pituitary to release other hormones (H.1.) into circulation. 2) Hormone 1 (I.e. thyroid stimulating hormone): goes to endocrine gland (I.e. thyroid gland) 3) thyroid releases a hormone (t3/t4) that works on body cells but that hormone level is detected by the hypothalmus 4) in response, as those levels go up, hypothalmus stops making so much releasing hormone (bc that's what's triggering the t3/t4 increase. we got too much at this point!) eventually, will stop making RH. ** NEGATIVE FEEDBACK LOOP --> RETURN TO HOMEOSTASIS
Explain the five "Mechanisms of Intercellular Communication."
1) direct : 2) paracrine 3) autocrine 4) endocrine 5) synaptic SPADE
alarm phase
1) energy reserves are mobilized in the form of glucose 2) body prepares for fight/flight EPI!
what are the 4 things that cortisol does for the body?
1) saves blood sugar for the NS 2) increase lipolysis (make energy out of fat) and glycogenesis (make glycogen out of sugar) 3) increases protein catabolism - takes proteins and break them down into a.a. to be released into the blood 4) decrease inflammatory response ** Gluconeogenesis - creation of glucose out of proteins (bad in long terml
Prolactin RELEASING /INHIBITING hormone stimulates which trophic cell?
LACTOtrophs ** note that growth/lactin is the only hormones that have releasing/inhibiting
how are lipid derivative hormones transported in the blood?
LIPID soluble aka (hydrophobic) Needs transporter like a binding protein (Thyroxine-binding globulin [TBG]) and androgen i.e. Testosterone, estrogen, aldosterone, cortisol (come from cholesterol)
describe positive feedback loop for hormone release
OXCYTOCIN -childbirth/increasing contractions * pregnancy and the continued release of oxytocin to increase the rate of contraction
What are the effects of Parathyroid hormone (PTH) -- 4 things
PTH = TOO LITTLE - Stimulated by: CALCium in blood is BELOW 8.5 - Parathyroid gland release ParaTHYROID Hormone - PTH binds Receptor on Osteoblasts, releasing Rank L - Rank L acts in a paracrine fashion to INCREASE: --> RESORPTION by OSTEOCLASTS --> REABSORPTION by KIDNEYS (of calcium) --> INCREASE renal secretion of CALCITRIOL aka vitamin D --> INCREASE ABSORPTION by G.I --> osteoclast resorption --> increase monocyte fusion to create new osteoclasts.
pathway for glucagon
Sleeping = sugar levels are dropping → alpha cells in pancrease respond and release glucagon into blood → targets the liver, where glycogen is stored → glycogen is broken down into glucose → glucose keeps your thing up ALPHA GLUCAGON AG I NEED SUGAR
which are the true endocrine glands?
TAPP: thyroid gland adrenal gland pineal gland pituitary gland because their function is only hormonal!!! ** those that aren't true have endocrine function BUT OTHER FUNCTIONS TOO
Describe the locations of and the anatomical relationships between the hypothalamus, anterior pituitary and posterior pituitary glands. [Review module 13.2, & 13.8].
The hypothalamus is superior to the pituitary gland, the A.P. is facing anteriorly/ventral, the P.P. is behind the A.P. facing posteriorly/dorsal (relative to body directions).
endocrine
cell makes a product, releases into ECF, through circulatory system, and throughout the body ** remember this is why hormones are slower than neurons
autocrine
a cell makes its product, exports it to the ECF, and the product gets fed back to effect itself ** what i release will automatically affect myself ** i'm a glandular cell, i release it, and then it affects me. comes back to bite me in the butt
RH/IH only affect the cells of the _____ pituitary. why not the other?
anterior pituitary. posterior pituitary has neurons that will make/deliver oxytocin or antidiuretic hormones directly to the posterior pituitary, so it doesn't need RH/IH.
what is tyrosine
base structure for making adrenaline (E, NE, dopamine; catecholAMINes) ** 80% of what our adrenal medulla makes is E, so its the bulk of adrenaline ** NE is more of a neurotransmitter than a hormone
who releases/What are the effects of calcitonin
calcitonin = calcium? TOO MUCH! ** 8.5-11.0 normal range** - Stimulated by: CALCium in blood is over 11.0 - Clear cells (a.k.a. Para-follicular cells) of the thyroid release CALCitonin - DECREASE in: --> DECREASE RESORPTION by OSTEOCLASTS --> DECREASE REABSORPTION by KIDNEYS (don't reabsorb it, so we pee it out) --> DECREASE ABSORPTION by G.I.
