Theme 1: The Endocrine System

Question 1

What are the 7 functions of the endocrine system?

Answer 1

• 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.

Question 2

What is the endocrine system?

Answer 2

Is the hormonal pathway of communication throughout the body, comprises of series of glands that secrete a variety of hormones into the blood stream.

Question 3

What are the types of glands in the endocrine system?

Answer 3

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.

Question 4

Label this diagram of the glands in the endocrine system

Answer 4

A - thymus
B - pineal gland
C - thyroid
D - adrenal glands
E - uterus
F - ovaries
G- testes

Question 5

What are the two types of hormones?

Answer 5

Water-soluble
Lipid- soluble

Question 6

What are water soluble hormones?

Answer 6

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.

Question 7

What are lipid soluble hormones?

Answer 7

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.

Question 8

What causes stimulation of hormones?

Answer 8

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

Question 9

What are examples of inhibition of hormones

Answer 9

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

Question 10

What can effect our hormone levels throughout life?

Answer 10

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.

Question 11

Question 12

What is the hypothalamus responsible for?

Answer 12

Growth, control of hunger, thirst, thermoregulation, sexual development and regulation of stress defences

Question 13

What 9 hormones does the hypothalamus and pituitary gland secrete

Answer 13

1. Growth hormone (somatotropin) releasing hormone (RH) > stimulates hormone release from anterior piturity gland
2. Thyrotropin - RH > stimulations thyroid hormones
3. Gonadotropin RH > stimulates follicle stimulating hormone and luteinizing hormone
4. Prolactin RH > stimulates prolactin
5. Corticotropin RH> stimulates adrenocorticotrophic hormone (ACTH)
6. Growth hormone (somatotropin) inhibiting hormone (IH) > inhibits thyroid stimulating hormone
7. Prolactin IH > inhibits prolactin
8. **Anti diuretic hormone ** > triggers collecting ducts in kidneys to re absorb more water
9. Oxytocin > smooth muscle contraction of uterus and let down reflex for breast milk ejection

Question 14

What is the difference between the anterior and posterior pituitary gland

Answer 14

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.

Question 15

What is the pineal glands crucial role?

Answer 15

Produce melatonin
Maintain circadian rhythms
Inducement of drowsiness

Question 16

What is the thyroid gland and what are the three major hormones it produces

Answer 16

• 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

Question 17

What are the parathyroid glands ?

Answer 17

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

Question 18

What are the issues the thyroid not working?

Answer 18

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.

Question 19

What are the thymus gland?

Answer 19

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

Question 20

What is the two structures of the adrenal gland?

Answer 20

**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

Question 21

What is the function of mineralocorticoids?

Answer 21

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.

Question 22

What is the function of glucocorticoids

Answer 22

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.

Question 23

What is the function of gonadocorticoids

Answer 23

Masculinization in both male and females

Includes testosterone

Question 24

What is the function of adrenaline?

Answer 24

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.

Question 25

What is the function of noradrenaline?

Answer 25

Part of the same response above, more related to the flight response.

Question 26

What is a gland that is both endocrine and exocrine called?

Answer 26

Heterocrine gland

Question 27

What is the role of the pancreas in the endocrine system?

Answer 27

Releases hormones to control the level of blood glucose

Question 28

What are the two types of cells found within the pancreas in the islets of langerhans?

Answer 28

** Alpha cells ** - responsible for release of glycogen

** beta cells ** - responsible for release of insulin

Question 29

What are the four hormones released by the pancrease? And what do they do!

Answer 29

insulin > targets cells to take up and use free glucose, to convert glucose to glycogen + insulin increases protein and lipid sythesis from glucose as well as slowing down glycogenolysis (decreasing blood sugar)

** glucagon ** targets the liver to break down glycogen > glucose, accolades lipids and protiens to produce glucose in gluconeogenesis) (increasing blood sugar)

Somatostatin inhibits the release of insulin and glucagon and slows absorption of nutrients from the GI tract

**pancreatic polypeptide ** inhibits somatostatin, contraction of gall bladder and secretion of digestive enzymes from the pancreas

Question 30

What are the types of diabetes?

Answer 30

Type 1 diabetes: results from the body’s failure to produce insulin in response to high blood glucose levels.

Type 2 diabetes: results from resistance to insulin, reducing the body’s ability to absorb glucose into cells.

Gestational diabetes: results from having a high blood glucose level during pregnancy.

Question 31

What are the male gonads and what are they responsible for producing?

Answer 31

Testes

Androgens mainly testosterone > regulates sperm production, maintains secondary sexual characteristics

oestradiol prevents death of germ cells

inhibin inhibits the production and release of follicle stimulating hormone (FSH)

Question 32

What is the female gonad and what hormone does it produce?

Answer 32

Ovaries

oestrogen Development and maintenance of female sexual characteristics, menstrual cycle, blood coagulation, regulation of sodium and water retention and increase of growth hormone and protein synthesis.

progesterone Together with gonadotropic hormones of the anterior pituitary gland and oestrogen, it helps regulate the menstrual cycle and maintain pregnancy. It also prepares the endometrium for implantation, as well as preparing breasts for milk production.

**inhibin ** inhibits the production of FSH

** relaxin ** Relaxes symphysis pubis, helps dilate uterine cervix at the end of pregnancy and plays a role in sperm motility.