Lecture 29 Flashcards
What can go wrong with hormone signalling
Secretion levels
- hyposecretion: too little hormone is secreted into the plasma
- hypersecretion: too mulch hormone is secreted into the plasma
What can go wrong with hormone signaling
Sensitivity of hormone receptors
- hypo sensitive- receptor that are less sensitiv, receptors get desensitised causing them to respond less or not at all ,
Hypothalamic-pituitary-adrenal axis
- Non stress stimuli
- hypothalamus secretes cortropin releasing hormone ( CRH )
- anterior pituitary gland secretes adrenocorticotropin hormone ( ACTH )
- adrenal gland ( cortex ) secretes cortisol
- targets and effectors of cortisol: liver, muscle and adipose, pancreas, cardiovascular system , immune system
Negative feedback: cortisol negatively feedbacks to reduce realise of CRH and ACTH
What is addisons disease, causes, hyposecetion disorder, symptoms
Hyposecretion of cortisol and aldosterone
Common cause:
- autoimmune disease that attacks the adrenal cortex
Hyposecretion disorder:
- reduced cortisol and aldosterone secretion causes reduction in normal effects
Symptoms
- low blood pressure
- fatigue; drowsiness; muscle weakness
- loss of appetite; weight loss
- craving salty foods; increased thirst
What is the Cushing disease
Hypersection of cortisol
Common cause:
- adrenal cortex tumour or taking glucocorticoid medication for long periods of time
Hyper secretion disorder:
- excess cortisol secretion causes amplification of normal effects, plus other symptoms
Symptoms:
- high blood pressure
- thinning or arms and legs; weight gain in torso
- buffalo hump at neck; moon face
- stretch marks and east bruising
Hypothalamic pituitary liver axis
The stimulus is excersize and sleep
Hypothalamus Secretion
- Releases Growth Hormone Releasing Hormone (GHRH) in response to exercise and sleep to stimulate the release of Growth Hormone (GH).
- Releases Growth Hormone Inhibiting Hormone (GHIH) (also known as somatostatin) to inhibit the release of GH when needed.
Anterior pituitary gland secretes
- growth hormone and this either goes to the liver, or liver,muscle,fat
Liver
- secrets insulin like growth factor 1 IGF-1
- chain keeps going to next stage: target of IGF-1: all body cells
Liver, muscle, fat
- full metabolism, and then the chain stops
target of IGF-1: all body cells
- effect: increase growth of cells
Dwarfism
Hyposecretion of growth hormone
Common causes
- genetic mutation or inheritance ( have short parents )
Hyposecretion disorder
- reduced growth hormone secretion
Symptoms
- short stature
Gigantism
Hyper secretion of growth hormone
Common cause
- pituitary gland tumour in childhood
Hyper secretion disorder
- excess growth hormone secretion before long bone have stopped growing ( epiphyseal plates have yet not fused )
Symptoms
- talk stature
Acromegaly
Hyper secretion of growth hormone
Common cause
- pituitary gland tumour in early adulthood
Hyper secretion disorder
- excess growth hormone secretion after longs bones have stopped growing
Symptoms
- large and irregularly shaped extremities and characteristic facial features
Hypothalamic pituitary thyroid axis
This is the process that stops when excersize stops or cold stress if removed
- stimulus- excersize and cold stress
- hypothalamus secretes - In response to the stimulus, the hypothalamus secretes Thyrotropin-Releasing Hormone (TRH).
- anterior pituitary gland - TRH stimulates the anterior pituitary gland to release Thyroid-Stimulating Hormone (TSH).
- thyroid gland secretes - TSH stimulates the thyroid gland to secrete thyroid hormones, primarily triiodothyronine (T3) and thyroxine (T4).
- target of thyroid hormone: all body cells - Thyroid hormones act on all body cells. Their effects include:
- Increasing the basal metabolic rate, regulating energy production and consumption.
- Stimulation of growth in fetus and during early childhood.
- Increasing mental alertness.
Hypothalimic piltary thyloid axis
This is the process that stops when excersize stops or cold stress if removed
- stimulus- excersize and cold stress
- hypothalamus secretes - In response to the stimulus, the hypothalamus secretes Thyrotropin-Releasing Hormone (TRH).
- anterior pituitary gland - TRH stimulates the anterior pituitary gland to release Thyroid-Stimulating Hormone (TSH).
- thyroid gland secretes - TSH stimulates the thyroid gland to secrete thyroid hormones, primarily triiodothyronine (T3) and thyroxine (T4).
- target of thyroid hormone: all body cells - Thyroid hormones act on all body cells. Their effects include:
- Increasing the basal metabolic rate, regulating energy production and consumption.
- Stimulation of growth in fetus and during early childhood.
- Increasing mental alertness.
Hypothalimic piltary thyloid axis
This is the process that stops when excersize stops or cold stress if removed
- stimulus- excersize and cold stress
- hypothalamus secretes - In response to the stimulus, the hypothalamus secretes Thyrotropin-Releasing Hormone (TRH).
- anterior pituitary gland - TRH stimulates the anterior pituitary gland to release Thyroid-Stimulating Hormone (TSH).
- thyroid gland secretes - TSH stimulates the thyroid gland to secrete thyroid hormones, primarily triiodothyronine (T3) and thyroxine (T4).
- target of thyroid hormone: all body cells - Thyroid hormones act on all body cells. Their effects include:
- Increasing the basal metabolic rate, regulating energy production and consumption.
- Stimulation of growth in fetus and during early childhood.
- Increasing mental alertness.
Infantile hyprothyroidism
Hyposecretion of thyloid hormone
Common causes:
• Missing or poorly developed thyroid gland
• Poorly functioning anterior pituitary
• Lack of iodine in mother’s diet
Hyposecretion disorder: reduced secretion of thyroid hormone causes reductions of its normal effects, plus other symptoms
Symptoms include:
• Low metabolic rate
• Delayed growth and development
• Swollen tongue and around eyes
Most affected infants have few or no symptoms and can be treated with thyroid hormone. Early diagnosis is essential to prevent permanent damage.
Adult hypothyroidism
(hyposecretion of thyroid hormone)
Common causes:
• Autoimmune disease
• lodine deficiency in diet
• Surgical removal of thyroid gland
Hyposecretion disorder: reduced secretion of thyroid hormone causes reductions of its normal effects
Some symptoms:
• Low metabolic rate; tiredness
• Weight gain
• Sensitive to cold
• Depression; brain tog
Simple Goitre
(hyposecretion of thyroid hormone)
• Common cause: lack of iodine in diet
• Hyposecretion disorder:
• Without iodine, the thyroid gland cannot make thyroid hormone.
• Without thyroid hormone negatively feeding back, TRH and
TSH get continually secreted.
• Excess TSH causes the thyroid gland to swell
• Symptoms:
• Enlarged thyroid gland = a goitre
