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72 Cards in this Set

  • Front
  • Back
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


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:


Growth Hormone


Hormone associated with this cell:

Mammotrophs (lacotrophs)



Hormone associated with this cell:




Hormone associated with this cell:


Thyroid stimulating hormone


Hormone associated with this cell:


- Luteinizing hormone

- Folliclestium


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


thyroid tumor

pregnancy and lactiation

under active parathyroid glands

what is hyercalcemia

blood levels too high,

nerve and muscle cells less responsive and exciteable


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


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


- immune systme

- Blood pressure maintain

- CNS activation

- vasculature

Feedback Loop of Cortisol

stress daily variation


corticotropin RH

Anterior Pituitary

Adrenocortiotropic H

Adrenal cortex


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


- 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


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


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