S4: The Ageing Endocrine System Flashcards
1
Q
List changes in the endocrine organ system with age
A
- Hypothalamus.
- Pituitary gland.
- Thyroid gland.
- Adrenal gland.
- Reproductive system.
- Pancreas.
- Parathyroid gland.
2
Q
What is the endocrine system?
A
- Made up of organs and tissues that produce hormones.
- A hormone is a chemical messenger that is released into the bloodstream from one location to target other organs or tissues. They are amino acid or steroid based.
3
Q
Role of Hypothalamus
A
- Links the NS to endocrine system via the pituitary gland.
- Main control centre for homeostasis - a balancing act.
4
Q
Describe ageing of the hypothalamus
A
- Circadian rhythm function diminishes with age. The central circadian clock is in the suprachiasmatic nucleus (SCN) in the hypothalamus.
- Decreased sleep and disturbed sleep/wake cycle
- Diminished appetite which is worse in dementia and also lose thirst
- Poor thermoregulation so it is more of a struggle to keep body temp up or down. Also don’t notice so don’t take action to correct.
- Reduction in number of cells.
- Vasopressin expressing neurons particularly reduced.
5
Q
Pituitary gland hormones
A
Anterior pituitary produces its own hormones and posterior pituitary stores hormones made in the hypothalamus. Growth hormone (GH) Oxytocin Anti-diuretic hormone (ADH) Thyroid stimulating hormone (TSH) Follicle stimulating hormone (FSH) Luteinising hormone (LH) Adrenocorticotropic hormone (ACTH) Prolactin
6
Q
Describe growth hormone (somatostatin) and its change in age
A
- GH stimulates growth, cell production and regeneration. It causes production of IGF-1 from liver and is involved in protein, fat and carbohydrate metabolism.
- · GH secretion from pituitary declines progressively after puberty leading to decreased levels of IGF-1. There is then decreased muscle mass and bone density. Muscle mass is reduced and replaced by fat.
- SOMATOPAUSE.
- Pulsatility decreases.
7
Q
Should growth hormone be replaced in individuals who have low levels?
A
Yes: - Increased lean body mass. - Decreased adipose tissue. - Increased bone density. No: - Has to be given subcut. - Difficult dosing. - Side effects e.g. hyperglycamia, oedema, arthralgia. - Increased IGF-1 can increase malignancy. - Cost.
8
Q
Describe melatonin production normally and in ageing
A
- Produced in pineal gland.
- Production is light sensitive.
- Peak in the middle of the night.
- Day and night time values of melatonin in serum during the ageing. Note the decline in melatonin levels in night time samples (made mostly in the pineal gland) which explains why older people need less sleep.
9
Q
Describe thyroid hormone changes in ageing
A
- Possible decrease TSH and T3.
- T4 levels remain unchanged.
- Increased levels of thyroid antibodies.
- Both hyperthyroidism and hypothyroidism are more prevalent in elderly but many are undiagnosed.
- There’s not much change noticed in hypothyroidism and hyperthyroidism can be mistaken for normal ageing.
10
Q
Why is thyroid disease tricky to detect in the elderly?
A
- Symptoms are non-specific and often mistaken for the ‘normal ageing’ process.
- Examination is difficult as thyroid may be shrunken and may have a kyphotic posture.
- Overlapping presentation of hypo- and hyperthyroidism in the elderly e.g. confusion, depression, decreased mobility, incontinence.
- Hypothyroidism - cerebellar dysfunction, carpal tunnel syndrome and neuropathies more common than in younger patients.
- Hyperthyroidism - cardiac complications occur more frequently e.g. AF, angina, heart failure.
11
Q
What does the adrenal glands produce?
A
- Cortex produces ALDOSTERONE and CORTISOL
- Medulla produces CATECHOLAMINES (adrenaline and noradrenaline)
12
Q
Describe adrenal function with age
A
- Cortisol is the STRESS hormone.
- Levels increase with age.
- The diurnal variation in cortisol is altered in the elderly.
- Chronically elevated levels have been implicated with numerous age-related conditions e.g. cognitive impairment, cardiovascular disease.
13
Q
Describe DHEA and changes in age
A
- Endogenous steroid hormone.
- Produced in adrenal gland, gonads and brain.
- Metabolite intermediate in biosynthesis of androgen and oestrogen sex steroids.
- Weak activity in own right.
- Levels decrease with age.
- Possible link to immune senescence.
14
Q
Describe gonadal function in ageing women
A
MENOPAUSE - ovulation decreases by age 40 and ovarian function ceases by the 6th decade. Post-menopause - oestrogen levels fall and FSH and LH increase initially and then fall.
- Increased cardiovascular risk.
- Rapid loss of skeletal mass and bone mass.
- Vasomotor instability.
- Psychological symptoms.
- Atrophy of oestrogen responsive tissue.
- Loss of libido.
15
Q
Should HRT be given as treatment?
A
Indications: - Menopausal symptoms where the risk : benefit ratio is favourable. - For women with early menopause. Benefits: - Improve vasomotor symptoms. - Reduction in osteoporosis. - Improve sleep and mood. - Reduce risk of colorectal cancer. - Reduce risk of CVD. Risks: - Small increase risk of breast, ovarian and endometrial cancer. - Increased risk of VTE. - Increased risk of stroke. - Increased risk of cholescystitis. - Side effects e.g. bloating, breakthrough bleeding, breast tenderness.
