Endocrine System Flashcards
Hormones (long or short distance?)
3 types (definitions)
Endocrine
Neuroendocrine
Exocrine
Long distance
Endocrine: secreted directly into bloodstream
Neuroendocrine: produced by neurons, secreted directly into bloodstream
Exocrine: secreted into a duct (can enter bloodstream)
T or F: cell must have receptor specific to hormone to be affected by that hormone
True
Short distance secreted peptides (need bloodstream?)
2 types (definitions)
Autocrine
Paracrine
Autocrine: exert effects on self or same type of cell
Paracrine: exert effects on nearby cells
Examples of effects of hormones
alter plasma membrane permeability
stimulate protein synthesis
activate/deactivate enzymes
induce secretion
stimulate mitosis
3 factors that impact level of target cell activation
- Blood levels of hormone
- Number of receptors on target cell
- Affinity of the receptors for the hormone (higher affinity: less hormone needed)
Up regulation vs down regulation
Up regulation: hormone binds, more receptors form
Down regulation: hormone binds, receptors lost
Hormones in the blood:
controlled by what feedback system?
Free vs bound (definitions)
Negative feedback system
Free: hydrophilic, most hormones
Bound: hydrophobic, bound to carrier proteins (steroids/thyroid hormones)
Blood hormone concentration: impacted by 3 factors
Rate of release
Speed of inactivation
Removal from body (enzymes in kidney/liver)
What is permissiveness?
One hormone can not work without another being present
Ex: thyroid hormone is permissive for epinephrine, cortisol is permissive for growth hormone
What is synergism?
Multiple hormones producing same effect on target cell
E
What is antagonism?
One or more hormones opposing the action of another hormone
What is a tropic hormone?
A hormone that regulates the secretion of other hormones
List all the non-tropic hormones
PRL: prolactin
MSH: melanocyte-stimulating hormone
B-lipoprotein
Humoral stimuli
Hormone release in response to ions/nutrients in blood
Neural stimuli
Hormone release stimulated by nerve fibers
Hormonal stimuli
Tropic hormones: regulate secretion of other hormones
Nervous system modulation
Nervous system can override regular negative feedback mechanism of endocrine glands
Ex. Under stress (need more glucose), hypothalamus + SNS override endocrine system to increase glucose levels
Eicosanoids
Life span
Derived from
3 types (+features)
Very short (seconds-mins)
Derived from arachidonic acid
Prostaglandins: prevent blood clotting
Thromboxanes: promote blood clotting
Leukotrienes: allergic reactions
Glucocorticoids: inhibit production of which eicosanoids
All 3: Prostaglandins, thromboxanes, leukotrienes
NSAIDs: inhibit production of which eicosanoids
Prostaglandins, thromboxanes
PGE2 vs PGI2
(Porstaglandin E2 vs Prostcyclin
PGE2: induces labour, vasodilator, pain, fever
PGI2: inhibits platelet aggregation, vasodilator
Amino-acid based hormones
Effect on adenylate cyclase
Protein Gs
Protein Gi
Gs: stimulates adenylate cyclase
Gi: inhibits adenylate cyclase
Signal amplification (in amino acid based hormones)
One hormone can lead to exponential amplification
Steroid hormones
Hydrophili/phobic?
Freely diffuse into plasma membrane? Nuclear membrane?
Hydrophobic (use transport protein for stability)
Freely diffuse into plasma membrane + nuclear membrane
Steps of steroid binding to chromatin
- Steroid enters nucleus
- Binds to receptor-chaperone complex, chaperone leaves
- Receptor-hormone (steroid) complex binds to chrmatin
- Second receptor-hormone complex needed to induce transcription (dimer)
Do steroids cause short/long term effects?
Is result seen immediately?
Long term, takes time to see result
Do all steroids work through gene expression? Give example
No, estrogen
T/F estrogen (E2) can perpetuate breast cancer tumour?
True
What are some ways that drugs interfere with estrogen (E2) promoting cancer?
- Block receptor from binding E2
- Block co-receptor in nucleus (prevents dimer forming)
- Induce receptor degradation
HER2 positive vs HER2 negative breast cancer? (2 things)
How does herceptin (actual name of drug?) reduce recurrence of breast cancer?
HER2 positive: increased recurrence of Breast cancer
HER2 negative: lower recurrence rates, higher life expectancy
Herceptin (trastizumab) blocks HER2 dimerization AND flags cancer cell for destruction by immune system.
Pituitary gland (alternate name?)
Posterior lobe name
Anterior lobe name
Connected by?
Hypophysis
Posterior lobe: neurohypophysis
Anterior lobe: adenohypophysis
Connected by infundibulum
Neurohypophysis
what kind of tissue?
Receives, stores, releases hormones from …
Examples of hormones?
Neural tissue
From hypothalamus
Oxytocin, Antidiuretic hormone
Adenohypophysis
what kind of tissue?
How is it connected to hypothalamus?
What type of hormones released? (example)
Glandular tissue
Connected through hypophyseal portal system (indirect)
growth hormone
Oxytocin:
From which lobe of which gland?
Pos/neg feedback?
Effect on birth?
Effect on lactation?
Effect on sexual arousal?
Posterior lobe (neurohypophysis) of pituitary gland
Positive feedback mechanism
Birth: causes intense uterine contractions (can be externally stimulated)
Lacation: oxytocin causes milk letdown, sucking on nipple releases oxytocin
Arousal: in males/non-lactating females
Antidiuretic hormone (ADH)
From which lobe of which gland?
Effect on urine output?
Alcohol effect on ADH?
Posterior lobe (neurohypophysis) of pituitary gland
Lowers urine output
Alcohol inhibits ADH, increases urine output
Growth hormone
From which lobe of which gland?
Anabolic or catabolic?
Key targets?
Tropic?
From adenohypophysis (anterior pituitary gland)
Anabolic
Liver, skeletal muscle, bone
Tropic
Gonadotropins:
From which lobe of which gland?
Examples
Effects in males/females
Tropic?
From adenohypophysis (anterior pituitary gland)
Follicle stimulating hormone (FSH) and luteinizing hormone (LH)
maturation of egg/sperm, release of estrogen/preogesterone/testosterone
Tropic
Prolactin (PRL)
From which lobe of which gland?
Triggered by:
Inhibited by:
Effect
Anterior pituitary (adenohypophysis)
Triggered by: hypothalmic prolacin-releasing hormone (PRH)
Inhibited by dopamine
In females, stimulates milk production (sucking increases PRH, increases milk)
Diseases from pituitary tumour (difference) - what happens?
Acromegaly vs Gigantism
before/after puberty?
What part of body is affected
Acromegaly: after puberty (epiphyseal plate closed), tissue swelling, pigmentation changing, skull expansion
Gigantism: before puberty, elongation of bones/fingers/toes
Thyroid gland
largest/smallest endocrine gland?
Releases which main hormone?
Largest endocrine gland
Thyroid hormone
Which things does thyroid hormone not affect? (acronym)
USTAT:
Uterus
Spleen
Testes
Adult brain
Thyroid gland (self)
Components of:
T4 thyroid hormone
T3 thyroid hormone
Which is more active? by how much
T4: 4 iodine + 2 tyrosine
T3: 3 iodine + 2 tyrosine
T3 is 5-10x more active than T4
Synthesis of thyroid hormone (6 steps)
- Thyroglobulin enters follicle lumen
- Iodides (I-) enter cell
- I- oxidized to I2
- Thyroid peroxidase forms T3/T4 with iodine + tyrosine (from thyroglobulin)
- T3/T4 enter lumen (with lysosome)
- Lysosomes cleave T3/T4 from thyroglobulin, enter bloodstream
Thyroid hormone (T3 and T4)
Mechanism of activity on body is similar to? How?
Effects are local or body wide?
Exceptions (acronym)
Similar to steroids, lead to production of mRNA for desired effect
Body-wide effects
USTAT: uterus, spleen, testes, adult brain, thyroid gland
Hypothyroidism:
From a deficiency in?
How does it happen?
What is goiter?
Additional symptoms
Iodine deficiency (can’t produce thyroid hormone)
Pituitary gland produces extra Thyroid stimulating hormone (TSH), doesn’t help since no iodine.
Leads to goiter: enlargement of thyroid gland
Low metabolic rate, lethargy, mental sluggishness
Hyperthyroidism (grave’s disease)
Type of disease?
How?
Common symptoms
Autoimmune
Abnormal antibodies mimic Thyroid stimulating hormone (TSH), cause excessive thyroid hormone release
Symptoms: goiter, bulging eyes (exophthalmos)
Calcitonin hormone
Which cells in thyroid produce it?
What does it do (to children)
Parafollicular cells
Lowers blood Ca2+ levels in children
How: inhibits osteoclast (bone breakdown) activity, stimulates Ca2+ incorporation into bone
Parathyroid gland
which hormone?
Effect on calcium?
Feedback loop?
Parathyroid hormone
Increases calcium in the blood
Negative feedback loop (more calcium inhibits PTH)
Adrenal glands
Adrenal medulla: part of … (NS)
Adrenal cortex: what type of hormones? (3 zones of cortex, 3 types of corticosteroids)
Adrenal medulla: parts of SNS
Adrenal cortex:corticosteroids (long-term stress)
Zona glomerulosa: aldosterones
Zona fasiculata: glucocorticoids
Zona reticularis: androgens
Adrenal cortex:Steroidogenesis
What is the overall precursor
Draw out pathway
Cholesterol overall precursor
Check with notes
Mineralocorticoids: main type?
What does it cause?
Secretion is impacted by (4 things, pos/neg?)
Aldosterone
Causes inc. blood pressure + volume
1. Low blood pressure (pos)
2. High K+ in blood (pos)
3. High stress (pos)
4. High blood pressure + volume (neg)
most potent estrogen?
E2
Cortisol:
What type of steroid? (where is it produced - gland + area)
How does it help reduce stress
Excessive levels of cortisol cause:
Glucocorticoid
Adrenal cortex (of adrenal gland)
keep blood glucose constant, maintain blood volume
Excess: dec. cartilage/bone formation, inflammation, inhibits immune system
Adrenal medulla:
What type of stress does it respond to?
Which neurotransmitters released?
Short-term stress
Norepinephrine + epinephrine
Short term stress vs long term stress (for each:
Part of adrenal gland stimulated:
Hormones/NT released:
Effects on body:
Short term stress: adrenal medulla, catcholamines (NE/E), inc. heart rate, blood pressure, reduced digestive/urinary output
Long-term stress: adrenal cortex, glucocorticoids (cortisol) + mineralocorticoids (aldosterone), inc. blood pressure, water/sodium retention, immune system suppression
Pancreas:
Islets: endocrine or exocrine?
3 types of islets + what do they produce
Islets are endocrine
Alpha: glucagon
Beta: insulin + amylin
Delta: somatostatin
Insulin:
effect on blood glucose
when is it released?
Decreases blood glucose
Released when glucose is high
Glucagon
effect on blood glucose
when is it released?
Increases blood glucose (breaks down glycogen, uses ketones from fatty acids)
Released when glucose is low
Type 1 diabetes
Which cells are attacked?
Hereditary?
Indications of type 1:
Long term effects of type 1:
Beta cells are attacked (autoimmune)
Hereditary
Polyuria: excessive urination
Polydipsia: excessive thirst
Polyphagia: excessive hunger/food consumption (body not using nutrients)
Blindness, loss of limbs,
Type 2 diabetes:
occurs in what type of people
Adult or childhood onset?
How to prevent?
Obese/sedentary ppl
Adult onset
Body does not respond to insulin
Good diet/exercise
Gonads: produce what
In females:
In males
Estrogen + progresteron
Testosterone
Pineal gland
Which ventricle of brain
releases what hormone
for what
third ventricle
melatonin
for sleep cycle
Thymus
how is it linked to lymphatics
Education of T cells
What hormone are secreted by
Adipose tissue
Leptin. resistin, adiponectin
What hormone is secreted by
Stomach
Gastrin
What hormones are secreted by
dueodenum
intestinal gastrin, secretin, checytokinin, incretins
What hormone is secreted by
heart
atrial natriuretic peptide
What hormone is secreted by
kidney
renin
What hormone is secreted by
skeleton
osteocalcin
What hormone is secreted by
skin
cholecalciferol
What hormone is secreted by
thymus
thymulin, thym-
The following are tropic hormones except:
TSH, FSH, LH, PRL, MSH, GH, ACTH
PRL (prolactin), MSH (melanocyte stimulating hormone)
