L4 - The Endocrine System - Glands & Hormones

Question 1

What’s the endocrine system

Answer 1

• works alongside the nervous system to control vital functions in the body, acts much more slowly than the nervous system but has very widespread and powerful effects
• Various glands produce hormones which are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone
• Most hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful responses

Question 2

Glands

Answer 2

• pineal gland
• thyroid gland
• thymus
• pancreas
• ovary
• adrenal glands
• placenta (in pregnant women)
• testicle

Question 3

Parts of brain involved in endocrine system

Answer 3

• The major endocrine gland is the pituitary gland, often called the ‘master gland’ as it controls the release of hormones from all the other endocrine glands in the body
• The hypothalamus is connected to the pituitary gland and is responsible for stimulating or controlling the release of hormones from the pituitary gland
• hypothalamus is the control system which regulates the endocrine system.

Question 4

Thyroid

Answer 4

• releases thyroxine
• Regulates the body’s metabolic rate and protein synthesis

Question 5

Adrenal medulla

Answer 5

• releases adrenaline & noradrenaline
• Fight or flight response, increases
• Increased heart rate and blood flow to the brain and muscles, release of stored glucose and fats for use in fight or flight responses

Question 6

Adrenal cortex

Answer 6

• releases Glucocorticoids, such as cortisone, cortisol and corticosterone
• this allows for further release of stored glucose and fats for energy expenditure. Suppression of the immune system and the inflammatory response
• also releases Mineralocorticoids
• These regulate the water balance of the body through water and sodium reabsorption in the kidneys.

Question 7

Testes

Answer 7

• Androgens mainly testosterone
• Development of male secondary sexual characteristics at puberty
• Promotes muscle mass and muscle growth

Question 8

Ovaries

Answer 8

• Releases Oestrogens mainly oestradiol
• Regulation of female reproductive system, menstrual cycle and pregnancy

Question 9

Pineal

Answer 9

• releases melatonin
• Regulation of arousal, biological rhythms and the sleep-wake cycle.

Question 10

Pituitary gland

Answer 10

• divided into an anterior and a posterior portion or lobe – these are distinguished by the hormones they release
• anterior (front)
• posterior (back)

Question 11

Anterior pituitary gland hormones

Answer 11

• Adrenocortical trophic hormone (ACTH) - Adrenal cortex, stimulating release of glucocorticoids such as cortisone and corticosterone. Key component in the stress response
• Thyroid stimulating hormone (TSH) - stimulates thyroxine
• Prolactin - Mammary glands, stimulating milk production and release
• Follicle stimulating hormone (FSH) - Ovaries and testes, stimulating release of ovarian follicles and promoting spermatogenesis
• Growth hormone - General promotion of cell growth and multiplication in the body
• Melanocyte stimulating hormone (MSH) - Stimulates the production and release of the pigment melanin in the skin and the hair

Question 12

Posterior pituitary gland hormones

Answer 12

• Vasopressin or antidiuretic hormone (ADH) - Involved in regulating the water balance of the body; stimulates water reabsorption by kidney and increases blood volume
• Oxytocin - Important in promoting uterine contractions in childbirth and lactation after birth