Endocrine - Overview Of Hormones

Question 1

What are the different types of intercellular messenger systems?

Answer 1

*neurotransmission
*neuronendocrine signalling
*endocrine signalling
*paracrine signalling
*autocrine signalling (self signalling)

Question 2

What are some examples of neurotransmitters?

Answer 2

Acetylcholine, dopamine, serotonin, glutamate, and GABA

Question 3

What are some examples of neuroendocrine hormones?

Answer 3

Oxytocin, vasopressin (ADH), and releasing hormones
from the hypothalamus (e.g., CRH, TRH)

Question 4

What are some examples of endocrine hormones?

Answer 4

insulin, thyroid hormones (T3 and T4), cortisol, and
sex hormones (oestrogen, testosterone)

Question 5

What are some examples of paracrine signalling molecules?

Answer 5

growth factors (e.g., VEGF), cytokines (e.g.,
interleukins), and local mediators like nitric oxide

Question 6

What are some examples of autocrine signalling molecules?

Answer 6

*cytokines
*prostaglandins and growth factors

Question 7

What are the endocrine’s system main functions?

Answer 7

*homeostasis
*growth and development
*stress
*metabolism
*reproduction

Question 8

What are the key components of the endocrine system?

Answer 8

*glands (specialised cells that release hormones)
*hormones (chemical messengers released into bloodstream)
*receptors (proteins that bind to specific hormones)

Question 9

What hormones regulate metabolism?

Answer 9

Thyroid hormones = T3 AND T4

Question 10

What hormones regulate growth and development?

Answer 10

*Growth Hormone (GH)

Question 11

What hormones do homeostasis?

Answer 11

*insulin and glugacon from pancreas regulate blood glucose levels

Question 12

What hormones release a stress response?

Answer 12

Cortisol from the adrenal cortex helps the body manage stress.

Question 13

What ways are hormones differentiated?

Answer 13

*structural (chemical) differences = distinguish the synthesis, storage, transportation and biological functions

Question 14

What are the hormone types?

Answer 14

*peptide hormones
*steroidal hormones
*amino acid derived hormone
*eicosanoids

Question 15

Where are peptide hormones secreted from?

Answer 15

hypothalamus, pituitary, pancreas and GIT

Question 16

What is the structure and some examples of peptide hormones?

Answer 16

*Structure: Chains of amino acids.
*Examples: Insulin, glucagon, growth hormone (GH), oxytocin, antidiuretic
hormone (ADH).

Question 17

What is the structure and some examples of steroidal hormones?

Answer 17

*Structure: Derived from cholesterol and has a characteristic four-ring structure.
*Examples: Cortisol, aldosterone, oestrogen, testosterone, progesterone

Question 18

What is the structure and some examples of the amino acid derived hormones?

Answer 18

*Structure: Derived from single amino acids, such as tyrosine or tryptophan.
*Examples: Thyroid hormones (thyroxine [T4], triiodothyronine [T3]),
adrenaline (epinephrine), noradrenaline (norepinephrine), melatonin.

Question 19

What is the structure and some examples of eiconsanoid hormones?

Answer 19

*Structure: Derived from arachidonic acid, a 20-carbon fatty acid.
*Examples: Prostaglandins, thromboxanes, leukotrienes.

Question 20

What is the peptide hormone target?

Answer 20

*G-protein on the cell membrane

Question 21

What is the steroidal hormone target

Answer 21

*acts on inner receptors = cytosolic receptor

Question 22

What are the types of steroid hormones and their receptors?

Answer 22

1.Glucocorticoids
* Examples: Cortisol, corticosterone.
* Receptor: Glucocorticoid receptor (GR)
2.Mineralocorticoids
* Examples: Aldosterone.
* Receptor: Mineralocorticoid receptor (MR)
3.Androgens
* Examples: Testosterone, and dihydrotestosterone (DHT).
* Receptor: Androgen receptor (AR)
4.Oestrogens
* Examples: Oestradiol, oestrone, oestriol.
* Receptor: Oestrogen receptors (ERα and ERβ)
5.Progestogens
* Examples: Progesterone.
* Receptor: Progesterone receptor (PR).

Question 23

What cells do glucocorticoids target? + function

Answer 23

Target Cells: Almost all body cells, including liver, muscle, adipose tissue, and immune cells.
Function: Regulate metabolism, reduce inflammation, and help the body respond to stress. In the liver, they stimulate gluconeogenesis. In the immune system, they inhibit inflammation

Question 24

What are the target cells and function of mineralocorticoids?

Answer 24

Target Cells: Kidney cells (primarily in the distal tubules and collecting
ducts), as well as cells in the colon, salivary glands, and sweat glands.
* Function: Regulate sodium and potassium balance by increasing sodium reabsorption and potassium excretion in the kidneys, thereby influencing blood pressure and fluid balance

Question 25

What are the target cells and function of androgens?

Answer 25

* Target Cells: Reproductive organs (e.g., testes, prostate), muscle, bone, skin, and the brain. * Function: Promote development and maintenance of male characteristics, increase muscle mass and strength, and influence libido and spermatogenesis

Question 26

What are the target cells and function of oestrogen?

Answer 26

* Target Cells: Reproductive organs (e.g., ovaries, uterus), breast tissue, bone, cardiovascular system, and brain. * Function: Regulate development and maintenance of female reproductive tissues, influence menstrual cycle and pregnancy, maintain bone density, and protect cardiovascular health

Question 27

What are the target cells and functions of progestogens?

Answer 27

* Target Cells: Uterus, mammary glands, brain, and other tissues. * Function: Prepare and maintain the uterus for pregnancy, regulate menstrual cycle and influence mammary gland development

Question 28

What is the simple feedback axis in a nutshell?

Answer 28

stimulus responds to need = if cold, turns heater on, if overheats, turn heater off

Question 29

What is the hypothalamus-pituitary axis (HPA)?

Answer 29

The Hypothalamus-Pituitary Axis is a complex set of interactions between the hypothalamus, pituitary gland, and various target endocrine glands. This axis plays a critical role in regulating hormone production and maintaining homeostasis

Question 30

What is the neuroendocrine reflex?

Answer 30

Neuroendocrine reflexes involve the integration of neural and endocrine responses to stimuli. These reflexes ensure a rapid and coordinated response to maintain homeostasis.

Question 31

What is an example of the neuroendocrine reflex?

Answer 31

*Example: The stress response. * Stimulus: Perceived threat. * Neural Response: The hypothalamus receives signals and activates the sympathetic nervous system. * Endocrine Response: The hypothalamus releases corticotropin-releasing hormone (CRH), stimulating the anterior pituitary to release ACTH, which in turn stimulates the adrenal cortex to release cortisol. Cortisol helps the body manage stress by increasing glucose availability, suppressing the immune response, and other actions.

Question 32

What is the circadian rhythms?

Answer 32

Circadian rhythms are 24-hour cycles in physiological processes regulated by an internal biological clock, primarily located in the suprachiasmatic nucleus (SCN) of the hypothalamus. These rhythms influence sleep-wake cycles, hormone release, and other bodily functions

Question 33

What is the diurnal rhythm?

Answer 33

* Diurnal Rhythms: These are circadian rhythms synchronised with the day-night cycle. * Sleep-Wake Cycle: The release of melatonin by the pineal gland is highest at night, promoting sleep. Cortisol levels peak in the early morning, preparing the body for wakefulness and activity

Question 34

How are cortisol, melatonin and GH affected by diurnal rhythm?

Answer 34

* Cortisol: Peaks in the early morning, declines throughout the day, and is lowest at midnight. * Melatonin: Increases in the evening, peaks during the night, and decreases in the morning * Growth Hormone: Secreted in pulses, with the largest release occurring shortly after the onset of sleep

Question 35

What is the enzymatic processes (metabolism of hormones)?

Answer 35

* Largely in blood, liver and kidney and some in target cells/tissues/organs *Excreted in urine

Question 36

Why do endocrine disorders happen?

Answer 36

Endocrine disorders arise from the dysfunction of endocrine glands, leading to either hypo- or hypersecretion of hormones

Question 37

What do ectopic hormonal disorders arise from?

Answer 37

Ectopic hormonal disorders arise when hormones are secreted by non-endocrine tissues. This can lead to secondary hormonal imbalances, as the ectopic source overrides normal regulatory mechanisms. Such conditions are often associated with malignancies but can also be caused by benign tumours or hyper-plastic tissues.

Question 38

What are the common sources and effects of ectopic ACTH syndrome?

Answer 38

Common Sources: Small cell lung carcinoma, bronchial carcinoids, pancreatic tumours, and thymomas. . Effects: Excess ACTH stimulates adrenal glands to produce cortisol, leading to Cushing's syndrome. * Symptoms: Weight gain, hypertension, diabetes, muscle weakness, skin changes (e.g., purple striae), and immunosuppression

Question 39

What are some examples of tumour induced hypersecretion (endocrine disorder)?

Answer 39

* Pituitary Adenomas: Can cause excess production of growth hormone (GH), leading to acromegaly. * Adrenal Adenomas: Can produce excess cortisol, leading to Cushing's syndrome (also immunological factors)

Question 40

What are some causes of hyposecretion?

Answer 40

*genetic causes (genetic mutations can affect hormone synthesis or gland development) *immunological attack (autoimmune diseases can destroy endocrine gland cells) *destruction by disease (Infections or chronic diseases can damage endocrine glands) *surgical removal (Surgical removal of endocrine glands for medical reasons can lead to hormone deficiencies)

Question 41

What is decreased target cell responsiveness caused by?

Answer 41

*receptor-level issues Mutations or downregulation of hormone receptors reduce target-cell responsiveness.

Question 42

What is autoimmunity?

Answer 42

Autoimmunity occurs when the immune system mistakenly attacks the body’s own cells and tissues, leading to various autoimmune diseases

Question 43

Describe the process of autoimmunity?

Answer 43

1.Genetic Predisposition: Certain genes (e.g., HLA genes) increase the risk of autoimmunity. 2.Environmental Triggers: Infections, toxins, and drugs can trigger an inappropriate immune response. 3.Loss of Immune Tolerance: Failures in central and peripheral tolerance allow self- reactive lymphocytes to survive. 4.Activation of Self-Reactive Lymphocytes: Self-reactive B cells produce autoantibodies, and T cells attack self-antigens. 5.Inflammation and Tissue Damage: Cytokines, chemokines, and the complement system cause chronic inflammation and damage tissues

Question 44

Examples of autoimmune diseases?

Answer 44

*type 1 diabetes mellitus *grave's disease

Question 45

What is step 1 of diagnosis of endocrine disorders?

Answer 45

-signs and symptoms

Question 46

What are the signs and symptoms of hypo secretion?

Answer 46

Hyposecretion: Fatigue, weight gain/loss, cold intolerance, hypotension, hypoglycaemia, and specific organ dysfunctions (e.g., hypothyroidism causing slow metabolism)

Question 47

What are the signs and symptoms of hypersecretion?

Answer 47

*Hypersecretion: Weight loss/gain, heat intolerance, hypertension, hyperglycaemia, increased sweating, and organ-specific symptoms (e.g., hyperthyroidism causing rapid metabolism)

Question 48

What is step 2 to diagnosis of endocrine disorders?

Answer 48

imaging

Question 49

What is the purpose of imaging?

Answer 49

*Purpose: Detect the presence of tumours (primary or secondary) that may cause hormonal imbalances.

Question 49

What are the imaging techniques?

Answer 49

* Ultrasound: Commonly used for thyroid and adrenal glands. * CT Scan/MRI: Detailed imaging for detecting pituitary, adrenal, and pancreatic tumors. * Nuclear Medicine Scans: Thyroid scans using radioactive iodine

Question 50

What is step 3 of endocrine disorder diagnosis?

Answer 50

*hormone levels (clinical biochemistry)

Question 51

What are some treatment strategies for endocrine disorders?

Answer 51

* Hyposecretion/hormone deficiency – Replace the hormone (supplements) * Hypersecretion/hormone excess – Block the synthesis and release (drugs) * Impaired target-cell responsiveness – drugs to enhance cellular response to hormone * Tumour – radiotherapy or surgery

Question 51

What are the types of hormone tests?

Answer 51

* Single-Point (Baseline) Measurements * Purpose: Assess hormone levels at a single time point to identify abnormalities. Dynamic or Provocative Tests * Purpose: Evaluate the integrity of the feedback control mechanism stimulation Tests (For Suspected Hyposecretion) *Purpose: Determine if a gland can produce adequate hormone levels when stimulated. Suppression Tests (For Suspected Hypersecretion) *Purpose: Determine if hormone production can be suppressed, indicating hypersecretion.