aging and disease lecture 9- endocrine system

Question 1

what is a hormone?

Answer 1

a chemical signalling molecule that enables an event in one part of the bodyto have an effect elsewhere in the body. it traces in the blood to the target tissues

may be product from specialist organs like the endocrine glands. hormones can also be produced from cells distributed around the body

Question 2

what are the functions of the endocrine system?

Answer 2

involved in regulation of..
-Homeostasis (the internal balance of body systems)
-Electrolyte, water, nutrient balance in blood
-Cellular metabolism
-Glucose and mineral homeostasis
-Growth and development
-Reproduction
-Blood pressure control
-Response to a stress – e.g. illness or injury
-Production of immune cells

Question 2

how do hormones selectively target tissues?

Answer 2

-hormones circulate in blood, potentially coming into contact with all cells
-a particular hormone usually affects only a limited number of cells which are called target cells
-a cell is a target because has a specific receptor for the hormone which may be intracellular or on the cell surface

Question 3

what is the classical endocrine system made up of?

Answer 3

The classical endocrine system is made up of the glands that are specialised for producing and secreting hormones

Question 4

what are the major sites of nervous systems an endocrine system integration?

Answer 4

the hypothalamus and pituitary gland

Question 4

what is the hypothalamus?

Answer 4

a small region of the brain containing clusters of neurone and regulates much of the activity of the pituitary gland

Question 5

what are the steps to the Regulation of the synthesis and secretion of anterior pituitary hormones

Answer 5

1. Neurons in the hypothalamus release RELEASING/INHIBITING HORMONES
2. These hormones travel in a portal blood system to the anterior pituitary gland
3. Releasing Hormone - Ant Pituitary secretes hormones into blood, where it travels to its targets and produces its response (4).
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   Inhibitory Hormone – Ant Pituitary stops hormone secretion which in turn has knock on effect on target tissue (e.g. Growth Hormone Inhibiting Hormone)

Question 6

what is the difference between the posterior and the anterior pituitary glands?

Answer 6

posterior pituitary gland is an extension of the hypothalamus. antidiuretic hormone and oxytocin are synthesised in hypothalamus and stored in the post gland

the anterior pituitary is made up of epithelial cells and synthesizes and secretes several peptide hormones

Question 7

what is the pituitary gland?

Answer 7

sometimes called the master gland because it regulates many body functions and other glands

Question 7

what is an example of negative feedback?

Answer 7

Thyrotrophin-releasing hormone (TRH) from the hypothalamus stimulates production & secretion of Throid Stimulating Hormone (TSH) from the anterior pituitary.

TSH stimulates production of Thyroid Horomes ( T4 & T3) from the thyroid.

T4 & T3 have a negative feedback on the pituitary and hypothalamus, reducing production of TRH and TSH..

Question 8

what is the somatopause?

Answer 8

A gradual, progressive decline in growth hormone (GH) secretion with age, primarily due to reduced hypothalamic secretion of Growth Hormone-Releasing Hormone (GHRH

Question 8

what happens the the endocrine system in aging?

Answer 8

-Endocrine system generally functions well in most older people
-Levels of most hormones decline with age.
-Some hormones that increase, e.g. Follicle Stimulating hormone, Luteinising Hormone and norepinephrine.
-Target cells become less sensitive to the hormones.
-Chronic diseases, such as those affecting the liver and kidney, can affect the metabolism and excretion of hormones.
-Circadian rhythms are altered

Question 8

what is the menopause?

Answer 8

Natural part of ageing

Recognized to have occurred after 12 consecutive months of amenorrhea, for which there is no other obvious pathological or physiological cause.

UK average age for menopause is 51 (45-55)

Question 8

what are the effects of the somatopause?

Answer 8

Effects:
Decreased production of Insulin-like Growth Factor 1 (IGF-1).
Metabolic changes:
Increased body fat.
Decreased protein synthesis.
Reduced bone mass (osteopenia/osteoporosis risk).
Decline in immune function.

Mitigating Factors:
Exercise: Regular physical activity has been shown to slow the decline in GH and improve body composition, bone density, and metabolic health.

Question 9

what is the GH replacement for the somatopause?

Answer 9

Studies indicate no proven long-term benefits of GH replacement in healthy older adults.
Risks include insulin resistance, oedema, joint pain, breast tissue hypertrophy and increased cancer risk.
Focus has shifted toward safer interventions like exercise and healthy nutrition for mitigating effects of declining GH and IGF-1 levels without the risks associated with hormone replacement.

Question 10

what is hypothyroidism?

Answer 10

Thyroid gland produces T3 and T4 (thyroxine) hormones which are important for maintaining Basal Metabolic Rate.
Decrease in thyroid activity as we age
Reduction in production of T3 (T4 normal)
Increase in autoimmune thyroiditis in elderly females
Lack of dietary iodine

Question 11

do trans and non binary people experience the menopause?

Answer 11

Trans-men and non-binary people may experience menopause if they keep their ovaries and do not alter their hormone profile.
Research on transgender people and menopause is limited;gap in scientific literature regarding the experiences of transgender individuals going through menopause.
Require access tohealthcare that addresses their needs and concerns.

Question 11

what is the menopause?

Answer 11

Due to decline in oestrogen levels

Oestrogens are a group of steroid hormones

Many functions including development of secondary sexual characteristics in females and reproductive functions.

Oestradiol is the main oestrogen in cis women and is synthesized predominantly in the ovaries.

Within the ovary there are thousands of primordial follicles, which contain a primary oocyte surrounded by supporting cells

Caused by depletion of primordial follicles in the ovaries.
Females have 6-7 million oocytes at 20 weeks gestation, 2 million at birth. This follicular pool decreases gradually through life:
Once there are fewer than 1000 follicles, menopause occurs
No developing granulosa cells to produce oestrogen

Question 12

what is the ovarian follicle?

Answer 12

During the reproductive years, groups of follicles begin growing and developing
During each menstrual cycle, supporting cells develop into two cell layers – theca cells and granulosa cells
Theca cells produce androgen hormones, which are precursors for oestrogen
Granulosa cells convert androgens to oestrogens
One follicle becomes dominant, the others degenerate (undergo atresia)
At ovulation the dominant follicle releases the oocyte

Question 13

What is the second type of negative feedback?

Answer 13

GnRH secreted by the hypothalamus stimulates anterior pituitary to produce LH and FSH
FSH stimulates development of ovarian follicles
As follicles develop, they produce increasing levels of oestrogen.
Oestrogen is Initially low, but rises as follicles mature.
Low to moderate levels of oestrogen exert negative feedback on the hypothalamus and anterior pituitary.
This suppresses the release of GnRH, LH, and FSH, preventing excessive hormone production during the early to mid-follicular phase.

Question 14

what is the Role of Oestrogen in Positive Feedback before ovulation?

Answer 14

Positive feedback occurs when release of a hormone stimulates further hormone release, amplifying the response.
Shortly before ovulation, high and rapidly rising oestrogen levels from the developing follicle exert a positive feedback effect on the hypothalamus and anterior pituitary.
This leads to a surge in Luteinizing Hormone (LH) release.
Stimulates granulosa cells to produce even more oestrogen, reinforcing the cycle.
Triggers ovulation, releasing the mature oocyte from the dominant follicle
Ovulation halts the positive feedback loop as oestrogen levels drop, shifting hormone regulation back to negative feedback.

Question 15

what is the luteal phase?

Answer 15

After ovulation, the ruptured follicle transforms into the corpus luteum, marking the start of the luteal phase of the menstrual cycle.

Oestrogen levels initially drop post-ovulation but are soon maintained by the corpus luteum.

The corpus luteum produces both oestrogen and progesterone, with progesterone being dominant.

If fertilisation occurs, the corpus luteum continues producing oestrogen and progesterone to support the pregnancy until the placenta takes over hormone production.

If there is no pregnancy, the corpus luteum degenerates, oestrogen & progesterone levels fall, and menstruation occurs.

Question 16

what is reproductive aging?

Answer 16

The progressive loss of follicles is the hallmark of ovarian ageing.
As the number of follicles declines, the ovaries produce less oestrogen.
Reduced oestrogen results in weaker negative feedback on the hypothalamus and pituitary.
In response, the pituitary increases secretion of Follicle-Stimulating Hormone (FSH)

Question 17

what is hormone replacement therapy?

Answer 17

Types of HRT
Oestrogen + Progesterone for women with an intact uterus to protect against endometrial hyperplasia.

Oestrogen-only for women who have had a hysterectomy (no need for progesterone).

Progesterone:
Reduces the risk of endometrial hyperplasia and cancer, though not completely.
Can be given continuously, or cyclically, with intermittent progesterone

HRT Delivery Methods
Systemic options: Tablets, skin patches and slow-release implants are available.
Local options (for vaginal / bladder symptoms): vaginal tablets, cream or vaginal rings.

Question 18

what is the breast cancer risk?

Answer 18

Slightly increased risk of breast and ovarian cancer with HRT
Breast cancer is common – lifetime risk is 1:8
There are around 5 extra cases of breast cancer in every 1,000 women who take combined HRT for 5 years.
Studies have not shown an increase in deaths from breast cancer due to HRT.
The evidence for ovarian cancer risk is less conclusive, but some studies suggest a minor increased risk.
The risk appears lower for women starting HRT in their 50s compared to older age groups.
The elevated risk diminishes after discontinuation of HRT.

Question 19

what is the other effect of HRT to cardiovascular disease?

Answer 19

Oestrogen helps maintain vascular health by improving lipid profiles, enhancing endothelial function, and reducing inflammation.
After menopause, oestrogen levels decline, leading to a rapid rise in cardiovascular risk
Early initiation of HRT (within 10 years of menopause) may reduce the risk of CVD.
Initiating HRT beyond 10 years post-menopause may increase the risk of cardiovascular events, particularly stroke and venous thromboembolism

Question 20

what is the other effect of HRT to osteoporosis?

Answer 20

Oestrogen deficiency post-menopause triggers increased osteoclast activity, leading to bone resorption and loss of bone density.
HRT helps maintain bone density and reduce fracture risk during treatment, particularly vertebral and hip fractures
Not generally recommended as a first-line preventive therapy for osteoporosis unless for women with premature menopause (< 40) or those at high fracture risk.
Alternatives such as bisphosphonates or selective estrogen receptor modulators (SERMs) are preferred for long-term prevention

Question 21

what’s the relationship between HRT and aging?

Answer 21

HRT plays a critical role in managing the hormonal changes associated with menopause, but it requires careful consideration.
HRT should be prescribed primarily for the relief of menopausal symptoms (e.g., hot flushes, vaginal dryness).
Treatment should be initiated only after an individualised assessment of the patient’s risks and benefits.
The lowest effective dose for the shortest duration necessary to control symptoms should be used.
HRT users should undergo a yearly assessment with their GP to evaluate whether continuation is appropriate
Starting HRT in women over 60 years is generally not recommended due to increased risks of cardiovascular disease and other complications.
Earlier initiation, particularly within 10 years of menopause, may offer better outcomes

Question 22

what are the non-pharmacological management options?

Answer 22

Nutrition – fruit, veg & wholegrains forgeneral health; vit D Supports calcium absorption and bone metabolism & calcium for bone bone strength and maintenance
Stop smoking – quitting can reduce hot flushes and improve cardiovascular health. Smoking also accelerates bone loss, increasing fracture risk in menopausal women.
Physical activity -Activities like walking, jogging, or resistance training strengthen bones and reduce the risk of fractures. Regular physical activity may improve mood and reduce anxiety.
Cognitive Behavioural Therapy - Effective for managing low mood, anxiety, and sleep disturbances commonly experienced during menopause. CBT has also been shown to alleviate the severity of hot flushes and night sweats by reducing stress and improving coping mechanisms.

Question 23

what are the other pharmacological treatments?

Answer 23

Vaginalmoisturisers& lubricants (non-hormonal)
Selected antidepressants,such as SSRIs (e.g., paroxetine)formooddisturbance
Anticonvulsant gabapentin for hot flushes
Fezolinetanta new drug (neurokinin-3(NK3) receptor antagonist – involved in temperature regulation) ; licensed in the UK December 2023; available on private prescription from mid-January 2024. A NICE Technology Appraisal (expected publication date May 2025) is underway to determine if this drug should be available on the NHS.

Question 24

what is there conflicting evidence/ no evidence for?

Answer 24

Herbal treatments including evening primrose oil,black cohosh,St John’s wort. Evidence for benefits is inconsistent.

“Bioidentical hormones” - marketed as a “natural” alternative to traditional HRT. These products are often unregulated, and their doses and purity may vary, increasing the risk of overdose, underdose, or contamination. Lack of robust clinical trials means long-term safety and efficacy are unclear.

Despite the appeal of being “natural,” these treatments may have serious side effects, including potential interactions with prescription medications.

Any treatment should only be taken after consultation with a qualified healthcare professional to assess individual risks and benefits.

The popularity of alternative treatments highlights the need for careful consideration and medical guidance, particularly for a potentially vulnerable population seeking relief from menopausal symptoms. Evidence-based treatments remain the safest option.