Theme 1: The Endocrine System Flashcards
What are the 7 functions of the endocrine system?
- growth and development
- stress responses
- sexual development and arousal
- glucose and mineral regulation
- control of weight
- emotional regulation
- responding to changes in environment such as temperature, dehydration etc.
What is the endocrine system?
Is the hormonal pathway of communication throughout the body, comprises of series of glands that secrete a variety of hormones into the blood stream.
What are the types of glands in the endocrine system?
Exocrine and endocrine glands
Exocrine glands > sweat and salivary glands.
Endocrine glands > stimulated by neural pathways, and release hormones depending if they are needed for a body function.
Label this diagram of the glands in the endocrine system
A - thymus
B - pineal gland
C - thyroid
D - adrenal glands
E - uterus
F - ovaries
G- testes
What are the two types of hormones?
Water-soluble
Lipid- soluble
What are water soluble hormones?
They are soluble in water, meaning they can be easily transported in the bloodstream without the need of a plasma protein
- they require receptors on the cell membrane to trigger reactions within the cytoplasm (mostly enzyme related)
- these reactions either change the permeability of the cell membrane, allowing molecules to pass through it, or it triggers the activation of other molecules within the cell.
What are lipid soluble hormones?
They are able to pass through the phospholipid liblayer, and bind to receptors inside the cell nucleus,
Examples include thyroid and steroid hormones which can directly control the function of the cells to prove more protiens via transcription.
- helps with growth and maintain body function.
- lipid soluble hormones require transportation from a plasma proteins as they are not soluble in water.
What causes stimulation of hormones?
Envirmental factors such as stress, temperature changes and physical activity
Tropic hormones which release further horses to trigger from another gland
Changes in internal body factors such as blood glucose, blood pressure
Positive feedback homeostatic mechanisms which require further normal regulation e.g childbirth
What are examples of inhibition of hormones
When envirmental factors change
The presence of inhibitor hormones that can either interfere with receptors to stop or slow down partiticular hormones
Negative feedback homeostasis, which identifies a high level of hormone is will slow or stop the production
What can effect our hormone levels throughout life?
Stress, lifestyle and wider determinants of health
For example, a family with a reduced salary will struggle to buy healthier options for food, and may turn to cheaper unhealthy food. This increases the risk of many endocrine related conditions, such as type 2 diabetes, hypothyroidism and obesity. It is why having an understanding of how wider determinants of health can impact an individual’s physiological wellbeing is important if we are to promote health.
What is the hypothalamus responsible for?
Growth, control of hunger, thirst, thermoregulation, sexual development and regulation of stress defences
What 9 hormones does the hypothalamus and pituitary gland secrete
- Growth hormone (somatotropin) releasing hormone (RH) > stimulates hormone release from anterior piturity gland
- Thyrotropin - RH > stimulations thyroid hormones
- Gonadotropin RH > stimulates follicle stimulating hormone and luteinizing hormone
- Prolactin RH > stimulates prolactin
- Corticotropin RH> stimulates adrenocorticotrophic hormone (ACTH)
- Growth hormone (somatotropin) inhibiting hormone (IH) > inhibits thyroid stimulating hormone
- Prolactin IH > inhibits prolactin
- **Anti diuretic hormone ** > triggers collecting ducts in kidneys to re absorb more water
- Oxytocin > smooth muscle contraction of uterus and let down reflex for breast milk ejection
What is the difference between the anterior and posterior pituitary gland
The anterior pituitary gland is the true glandular structure of the pituitary gland which releases hormones depending on stimulation from the hypothalamus
The posterior pituitary gland is made up of nervous tissue, and can store and release hormones depending on the body’s needs.
What is the pineal glands crucial role?
Produce melatonin
Maintain circadian rhythms
Inducement of drowsiness
What is the thyroid gland and what are the three major hormones it produces
- thyroxine (T4) and Triiodothyronine (T3) - regulate metabolism, stimulates body o2 and energy consumption - influences the nervous system and promotes proteins synthesis (metabolic rates and energy usage)
- calcitonin this is released in response to increasing calcium ions in the blood stream, it promotes re absorption of calcium into the matrix of the bones
What are the parathyroid glands ?
Produce parathyroid hormone (PTH) in response to low calcium levels and triggers osteoblasts to breakdown the bone matrix into realising calcium into the blood
Also activate vitamin d and decrease phosphate levels
What are the issues the thyroid not working?
Hypothyroidism (underactive thyroid) is a condition where a lack of thyroid hormones are produced and can result in lethargy, constipation, weight gain, depression, muscle cramps etc.
Hyperthyroidism (overactive thyroid) is when too much thyroid hormones are being produced, and it can result in symptoms such as difficulty sleeping, diarrhoea, mood swings, nervousness, anxiety, more need to wee etc.
What are the thymus gland?
Located in the chest
- is responsible for making a group of hormones called thymosins
» thymosis, thymus humoral factor, thymic factor and thymopoietin
They are responsible for the differentiation of primitive leukocytes and maturation of t-cells as part of immunise system
What is the two structures of the adrenal gland?
**The adrenal cortex **- is the outer layer, produces cortical hormones > glucocorticoids, mineralocorticoids and androgens
The adrenal medulla - adrenaline and noradrenaline if stimulated by the sympathetic neural channels of the autonomic nervous system
What is the function of mineralocorticoids?
Stimulates sodium reabsorption in the kidneys which helps increase sodium and water levels in the blood, increasing blood volume.
Stimulates secretion of potassium and hydrogen ions.
What is the function of glucocorticoids
Mainly cortisol
Stimulates gluconeogenesis and fat breakdown in adipose tissue, increasing glucose availability in the blood.
It also promotes metabolism and inhibits inflammation and immunological responses to protect the body against stress. Inhibits protein synthesis and glucose uptake in muscles and adipose tissue.
What is the function of gonadocorticoids
Masculinization in both male and females
Includes testosterone
What is the function of adrenaline?
Involved in the fight or flight response as a result of sympathetic response. It produces multiple effects including boosting oxygen and glucose supply to the brain and muscles by increasing heart rate and stroke volume. Reduces blood flow to organs and structures not needed in emergencies.
