The endocrine system

Question 1

What is the endocrine system

Answer 1

The endocrine system is made up of specialised ductless glands including the thyroid, adrenal and ovaries which release hormones into the blood for communication

Question 2

What are hormones

Answer 2

Hormones are molecules that bind to receptors on target organs and trigger a specific action to be carried out

Hormones are chemical messages directly released into the blood.

Question 3

What is the posterior pituitary

Answer 3

The posterior pituitary is found at the back of the pituitary gland and is an extension of the hypothalamus

Question 4

What is the anterior pituitary

Answer 4

The anterior pituitary is the front portion of the pituitary gland formed from the roof of the mouth also known as a rathkes pouch

Question 5

What is the pars intermedia

Answer 5

The pars intermedia is where the anterior and posterior pituitary fuse

Question 6

What are some of the main functions of the posterior pituitary

Answer 6

The posterior pituitary secretes oxytocin which stimulates myometrium contraction, the let down reflex, promotes bonding and reduces nerve activity in babies brain during labour.
It also produces antidiuretic hormone

Question 7

What are some of the main functions of the anterior pituitary

Answer 7

It produces somatotropin which promotes the growth of bones by stimulating the epiphyses of long bones to widen.

Question 8

What are some of the main functions of the pars intemedia

Answer 8

The pars intemedia produces melanocyte stimulating hormone which controls skin pigmentation by stimulating melanocytes to produce melanin, responsible for melasma.

Question 9

What is the thyroid gland

Answer 9

The thyroid gland is a bilobed organ that sits below the larynx and is responsible for regulating metabolism by taking iodine used to make thyroxine, and also regulates blood calcium level.

Question 10

What is goitre

Answer 10

Goitre is a swelling of the thyroid gland due to an iodine deficiency

Question 11

What is hypothyroidism

Answer 11

Hypothyroidism is a condition caused by an autoimmune disease or ageing which causes reduced thyroxine secretion. This leads to a reduced metabolic rate, weight gain, drop in body temp, dry hair, hair loss and dry skin. In pregnancy it can increase the risk of miscarriage and preterm birth. It can present as increased BP and anaemia

Question 12

What is hyperthyroidism

Answer 12

Hyperthyroidism is a condition caused by graves disease that leads to an over secretion of thyroxine and an increase in metabolic rate. This leads to weight loss, hair thinning, excess heat, tachycardia, tremors, goitre, increased sweating and bulging eyes. It can cause low birth weight and premature delivery in pregnancy

Question 13

What is the pancreas

Answer 13

The pancreas is part of both the endocrine ad digestive system, and found in the loop of duodenum. It contains the islet of Langerhans which produce glucagon by alpha cells, insulin by beta cells, ghrelin by epsilon cells and pancreatic polypeptide by PP cells.

Question 14

What is ghrelin

Answer 14

Ghrelin is the hunger hormone that peaks before meals and binds to receptors in the hypothalamus to elicit hunger

Question 15

What is pancreatic polypeptide

Answer 15

Pancreatic polypeptide is the satiety hormone that switches off hunger after a meal. It can be reduced in overweight people and overproduced in anorexic people.

Question 16

How does the body regulate blood glucose levels

Answer 16

When alpha cells detect a drop in blood glucose they release glucagon which binds to hepatocytes in the liver causing them to release glucose.
When beta cells detect an increase un blood glucose levels they release insulin which binds to cell receptors causing glucose transporter protein channels to embed in the membrane allowing glucose to move in

Question 17

What is gestational diabetes

Answer 17

Gestational diabetes is a condition found in 5% of pregnant women which raises glucose levels by inhibiting the normal action of insulin. This increases thirst and urination, and can lead to macrosomia which is where babies grow very large.

Question 18

What are the adrenal glands

Answer 18

The adrenal glands sit on top of the kidneys and have the outer cortex and the inner medulla

Question 19

What is the function of the medulla in the adrenal glands

Answer 19

The medulla produces adrenaline which gears the body for activity by raising HR, vasoconstriction of skin vessels and vasodilation of vessels in organs, increasing blood glucose and increases oxygen uptake.

Question 20

What is the function of the cortex in the adrenal glands

Answer 20

The cortex takes up cholesterol to produce steroid hormones.