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72 Cards in this Set

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Water soluble hormones

-Hyrdophillic, easily dissolved in water so blood


- Produced in gland cell and stored there until needed (released by exocytosis)


- made up of peptide (75%) and catecholamine


- made and stored until required

Lipid soluble hormones

-Hydrophobic, unable to mix with water so requires a carrier protein


- Steroid hormones made from cholesterol


- Thyroid hormones made in thyroid cells


- steroids not stored, made as required


- thyroid made in thyroid cells and stored until required

Function of endocrine system

Regulate internal environment by secreting hormones that travel through the blood stream to target areas

Hormones definition

chemical messengers produced in one location and transported to a second location (target cells) where they exert their effects.

Cellular responce to Water Soluble Hormones

1. WSH bind to cell surface receptor


2. Hormone binding activate G Protein


3. G Protein activates adenylyl cyclase


4. adenyly cyclase converts ATP to AMP (cAMP)


5. cAMP activates protein kinase


6. protein kinase activate specific enzyme


7. enzyme converts specific substrate to product

Cellular responce to Lipid Soluble Hormones

1. Lipid soluble hormone dissociates from carrir protein


2. hormone diffuse across cell membrane


3. hormone bind to Intracelullar receptor


4. hormone rec acts as specific hormone TRANSCRIPTION factor


5. new mRNA generated


6. new protein generated by TRANSLATION of mRNA


7. new protein mediate cells specific responce

specific hormone action

a hormone can only affect cells with specific receptors for that hormone

Receptors on water sol and lipid sol

water sol - on surface


lipid sol - intracellular receptors

mechanism of action of water and lipid sol

water sol - 2nd messengers


lipid sol - alter gene transcription

speed of response in lipid and water sol

water sol - milli sec to mins


lipid sol - hours to days

sensitivity of a target cell

depends on number of receptors expressed for that hormone

Compare endocrine and neuronal control systems

Neuronal - action potentials in axons and neurotransmitter release at the synapse


- fast and specific


- good for brief response


Hormonal - hormones released into the blood


- slow but sustained


- widespread

Hypothalamus and Posterior Pituitary

- connected by neurons, cell bodies in hypothalamus and axons in posterior lobe


- neural communication, freq of AP to posterior lobe determines the rate of hormone secretion



Posterior pituitary hormones

- made in hypothalamus


- travel down axon


- stored in the axon ends until required


ADH regulation (PP Hormone)

PP releases ADH into bloodstream


Effector: Kidneys


Responce: kidneys conserve water, decrease ECF conc (neg feedback)


Stimulis: increase in ECF (dehydration)


Sensor: Osmoreceptors


Intergrator: Hypothalamus


NOTE SENSOR AND INTERGRATOR ARE IN THE HYPOTHALAMUS

Anterior Pituitary Hormones

1. Growth (GH)


2. Adrenocorticospinal (ACTH)


3. Thyroid Stimulating Hormone (TSH)


4. Gondadotropic (FSH and LH)


5. Prolactin (RRL)

Posterior Hormones

1. Artidiuretic (ADH)


2. Oxytocin (OT)

ADH Antidiuretic role

stimulate kidneys to reabsorb water


made in hypo and stored until needed

Oxytocin role

- stimulate contraction of uterine muscles during childbirth (positive feedback)


- stim breast milk release in breast feeding


- made in hypo and stored until needed

Milk ejection reflex

- signal is the sucking on the nipple, sends message via pathways to the hypothalamus and releases the hormone oxytocin so that milk can be released

Hypothalamus and Anterior Pituitary

- hypo and ant connected by blood vessels


- communicates by releasing hormones


- releasing and inhibitory


- ant pit hormones are made in the ant pit by specific cells



Feed back regulation of the anterior pit gland

- hypothalamus


- releasing hormone


- anterior pituitary gland


- pituitary hormone


- target organ


- hormone


- effect


Note some go back to hypothalamus and anterior pit to signal to stop.

Negative feedback Prolactin

principal regulator is prolactin inhibiting hormone (PIH)


PIH is dopamine


prolactin stimulates PIH secretion to inhibit prolactin secretion


stimulate breast develop, milk synthesis

Hormone associated with this cell:


Somatrophs

Growth Hormone


50%

Hormone associated with this cell:


Mammotrophs (lacotrophs)

Prolactin


20%

Hormone associated with this cell:


Corticotrophs

Adrenocorticotropichormone


20%

Hormone associated with this cell:


Thyromophs

Thyroid stimulating hormone


5%

Hormone associated with this cell:


Gonadotrophs

- Luteinizing hormone


- Folliclestium


5%



Regulation of Growth Hormone

1. GHRH released from hypothalamus


2. somatrophs release GH and target Liver


3. IGF 1 back to Hypo GHRH in brain


4. IGF 1 also can be positive feedback to the SS neurons



Growth hormone

- peptide hormone


- water soluble


- 2nd messenger process


- cell surface receptor



Effects of GH


Long and Short term

LT - Stim bone, muscle and tissue growth by cell division at IGF 1


- stim protein synthesis


ST - Incease Blood Glucose


- Increase Triglyceride breakdown and free fatty acid in adipose tissue

Growth hormone levels peck most when?


Gender differences?

At night time, but fluctuate during the day depending on meals and activities.


Gender -


Male - small during day major when sleep


Female - extended bursts during the day, longer not so pronounced when sleeping.



Disorders for GH

Hypersecretion - too much


- giantism


Hyposecretion - too little


- dwarfism




hyposensitive - little or no response in hormone receptors


hypersensitive - respond too much

Hormones important for growth

1. Thyroid - increase basal metaboliic rate


- essential for nervous system dev


2. Insulin - glucose metabolism


3. Cortisol - glucose metabolism


4. Testosterone - purbety

Thyroid gland location and hormones that are made and secreated

below the layrnx


thyroid hormone - basal metabollic rate


calcitonin - calcium homeostasis

Structure of Thyroid gland

compsed of follicles and each one surrounded by follicular cells




Follicular cells make thyroglobin and secrete it into the folicle




c-cell or parafollicular make the hormone calcitonin

Thyroid secretion steps

1. iodised TGB moves into follicular cells


2. thyroid hormones released from the iodised TGB


3. thyroid hormones have two forms


4. T3 (active) and T4 (more plentiful)


5. T3 and T4 secreted into blood travel to carrier protein to target cells.

Effects of Thyroid Hormone

1. Metabolism


- increase body heat production


- decrease triglceride and chol levels


- set basal metabollic rate


2. Growth


- normal growth in child


- growth retardation in thyroid deficiency


- essential for development of fetal brain.

Disorders with thyroid hormone

Hypo secretion - too little


- low met rate


- weight gain


- cold intolerance


Hyper secretion - too much


- increase met rate


- heat intollerant


- nervous


- increase heart rate





Calcitonin hormone

- controls levels of Ca2+ (controls ca in blood 1%)


- parafollicular or c-cells make this hormone



Increase in Ca2+

calcitonin secretion


osteocleast reduce activity - less bone resorption


osteoblast increased activity - more bone deposition


Blood ca2+ returns to normal

Calcitonin improtant in children

because osteoclasts take 5g of calcium from bone to blood each day where as adults is only 0.8g

Parathyroid glands

secrete parathyroid hormone



PTH and Calcitonin effects on Ca2+

PTH increases bone break down


Ca2+ decreases bone break down




together maintain homeostasis

Blood Ca2+ levels too low?

increased excitability of nervous system


muscle tremors and cramps


begins as ca2+ falls to 6mg


at 4mg larynx contracts and suffication

Causes of hypocalcemia

vit D deficent


diarrhea


thyroid tumor


pregnancy and lactiation


under active parathyroid glands

what is hyercalcemia

blood levels too high,


nerve and muscle cells less responsive and exciteable



hyperparathyroidism

leads to excess PTH secretion


caused by parathyroid tumor


bones soft


raises blood levels of ca2+


kidney stones

adrenal glands location and structure

above the kidneys


secretes steroid hormones


2 sections adrenal cortex and adrenal medulla



3 layers in the adrenal cortex


and what they secrete

Glomerulosa - aldosterone


Fasciculata - Cortisol


Reticulas - androgens eg testosterone



Inner Medulla

releases epinepherine and NE


Sympathetic nervous system - acute stress


Pre ganglionic SNS (ACH)

epinephrine binding system used

uses a 2nd messenger system

effects of inner medulla norepinephrine and epinephrine

- increase fat and glucogen break down


- decrease GI


- increase heart rate


- increase blood flow to muscles



Coritsol

lipid soluble so uses steriod mechanism of action


happens in mins to days



effects of cortisol

-gluconegenesis (produce glucose in the body)


- increase protein breakdown


- decrease glucoes uptake in muscle and fat


OTHER


- immune systme


- Blood pressure maintain


- CNS activation


- vasculature

Feedback Loop of Cortisol

stress daily variation


hypothalamus


corticotropin RH


Anterior Pituitary


Adrenocortiotropic H


Adrenal cortex


Cortisol

Pancreas location

abdominal cavity

sturture of the pancreas

exocrine glands - secrete digestive enzymes


endocrine glands - secrete pancreatic islets

pancreatic islets

beta cells - secrete Insulin (decrease BG)


alpha cells - secrete glucagon (Increase BG)



Blood glucose fasting range

3.3 to 4.4

Blood glucose levels are too high

1. beta cells release insulin into the blood


2. Insulin


3. body cells take up more glucose


4. blood glucose levels decline to a set point

Blood glucose levels are too low

1. alpha cells of the pancreas stimulated to relase glugagon into blood


2. Glugagon


3. liver breaks down glugogen (stored form of glucose) and releases it into the blood.


4. blood glucose levels rise and come to sp

target cells when beta secretes insulin are

muscle and adipose fat (increase glucose uptake)


liver cells (increase net glucose uptake)

target cells when alpha secretes glucagon

Liver


- increase the breakdown of glycogen


- increase glucose synthesis


- increase ketone synthesis

Hormonal control of blood glucose

- Pancreatic Islets 1. insulin 2. Glugagon


- Pituitary 1. growth hormone


- Adrenal glands 1. adrenaline 2. cortisol

Insulin action

1. insulin on receptor


2. allows the glucose channels to open


3. glucose into the cell via GLUT4


4. Hexokinase


5. make glycogen or ATP



Insulin resistance

Fatty acids


Diacylglycerol


Glucose is not entering the cell as the diacylglycerol switches off the pathways

long term isulin resistance leads to

impaired B cell function

ketone synthesis use

can be used as a last resort for the brain

glut 4 and glucose and insulin have no effect on..

brain cells

Type 1 diabetes

10 % diabetics


Symptoms:


high blood glucose


Glucose in urine


large urine volume


Diagnosed: child


Cause: Insulin producing beta cells and destroyed


Treatment: Insulin injections

Type 2 diabetes

90% diabetics


- cells are reisistant to insulin signals to store food, cells are starving as glucose can't be used.


- Risk factors: obesity, ethics, genetics


Treatment - exercise and diet