lecture 1 (week 7)

Question 1

what are the main endocrine glands in the body?

Answer 1

the pituitary, thyroid, parathyroid, adrenal and pancreatic islets (islets of langerhans)

Question 2

what is an exocrine function?

Answer 2

exocrine glands develop from epithelial cells to form ducts which secrete substances onto the surface of epithelial cells (i.e. body cavities) e.g. salivary glands, sebaceous glands, sweat glands.

Question 3

what is the difference between endocrine glands and exocrine glands?

Answer 3

endocrine glands do not have any ducts, they are clumps of cells with a rich blood supply (i.e. they are highly vascularised) and secrete HORMONES into the ECM where it diffuses into the bloodstream via capillaries (venous system).

Question 4

what are the three different types of hormones?

Answer 4

proteins/polypeptides; steroids (modified cholesterol); amino acid derivatives (thyroid hormones, catecholamines (adrenalin, dopamine noradrenalin)

Question 5

what are paracrines?

Answer 5

hormones which act locally. Can act on other tissue types in the ECM of the glands via diffusion - no bloodstream transport required.

Question 6

what is autocrine signalling?

Answer 6

hormones which act on the same cell type as the type which they were secreted from. Involved in negative feedback control.

Question 7

how are peptide neurotransmitters an endocrine hormone?

Answer 7

peptide neurotransmitters can diffuse away from the axon bulb and act on other adjacent neurones.

Question 8

what is the pineal gland and where is it located?

Answer 8

the pineal gland is located near the back of the brain and is involved in producing melatonin (sleep-inducing hormone).

Question 9

what is the thymus gland and where is it located?

Answer 9

located between the lungs, above the heart and is very active before puberty and is involved in producing white blood cells throughout life.

Question 10

where are the adrenal glands located?

Answer 10

on top of the kidneys

Question 11

how can concentrations of hormones in the blood vary?

Answer 11

can be diurnal, episodic or pulsatile. Some are secreted by circadian rhythms.

Question 12

how are hydrophobic hormones transported in the blood? (e.g. steroids and thyroid hormones)

Answer 12

By carrier proteins (hydrophilic proteins) which coat the surface of these hormones. this increase the hormones water solubility and the half-life which means it stays in circulation longer and can provide a reserve in the blood.

Question 13

are the hormones physiologically active when coated in the carrier proteins?

Answer 13

No, the carrier proteins have to diffuse off first before the hormones become metabolically active.

Question 14

how to hormones alter the cell biochemistry?

Answer 14

by binding to specific receptors - either on the cell surface or inside the cell.

Question 15

what type of hormones bind to receptors on the cell surface?

Answer 15

peptides, glycoproteins and catecholamines - hydrophilic hormones

Question 16

which types of hormones bind to intracellular receptors?

Answer 16

hydrophobic hormones (eg steroids and thyroid hormones) many are involved in gene transcription and can induce changes in protein synthesis.

Question 17

what are the two different regions of the pituitary gland?

Answer 17

anterior pituitary and posterior pituitary

Question 18

what is the function of the anterior pituitary (also called the adenohypophysis) and what did it develop from?

Answer 18

the anterior pituitary gland developed from epithelial cells of the mouth and the hypothalamus releases GnRH which acts on the anterior pituitary

Question 19

what is the function of the posterior pituitary (also called the neurohypophysis) and what did it develop from?

Answer 19

the posterior pituitary is a down growth of the hypothalamus and consists of neural axons. stores and releases hormones which are secreted by the hypothalamus (by neurosecretory cells) including oxytocin and ADH

Question 20

what is the function of the hypothalamus?

Answer 20

secretes hormones which control secretion and release of pituitary hormones. controls release of anterior pituitary hormones via hormones .

Question 21

which six hormones are released from the anterior pituitary gland?

Answer 21

Growth hormone, thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH) (acts on the adrenal glands to stimulate the production of moe cortisol), follicle stimulating hormone (FSH), Lutenising hormone (LH) and prolactin

Question 22

why is the control of the secretion of prolactin by the hypothalamus different?

Answer 22

the hypothalamus releases prolactin-release inhibiting factors.

Question 23

what is the function of ADH (antidiuretic hormone)

Answer 23

in small concentrations, promotes reabsorption of water in the kidney. in large concentrations, causes constriction of blood vessels to maintain blood pressure (e.g. in cases of extreme trauma with a lot of blood loss)

Question 24

what is the function of oxytocin?

Answer 24

important in birth and also causes release of milk in the breasts by constricting the alveoli.

Question 25

why can tumours of the pituitary gland cause disease?

Answer 25

the pituitary gland is housed in a bony cavity so tumours forming on it can crush it in the small cavity and kill the cells.

Question 26

what is the purpose of an endocrine axes/cascade?

Answer 26

the final product acts to inhibit a hormone higher up the cascade. The hypothalamus is an important site of negative feedback in many hormone systems. (e.g. gonadal steroids inhibit the secretion of GnRH)

Question 27

what is acromegaly?

Answer 27

a condition caused by overproduction of growth hormone in the pituitary gland caused by a pituitary adenoma. If this happens after puberty results can include enlarged hands, feet nose and jaw.

Question 28

what is a pituitary adenoma?

Answer 28

a non-cancerous tumour in the pituitary gland

Question 29

where is the thyroid gland located?

Answer 29

at the top of the trachea, just below the larynx.

Question 30

what does the thyroid gland develop from?

Answer 30

the epithelium of the tongue.

Question 31

which hormones does the thyroid gland produce?

Answer 31

tri-iodothyronine (T3) an Thyroxine (T4) -structure is of 3 amino acids and iodine. these hormones are produced by the follicular cells. Also, the parafollicular cells produce calcitonin (stimulates osteoblasts)

Question 32

what is the function of thyroxin hormones?

Answer 32

regulates: energy use (metabolic rate), protein production (growth and development, sensitivity of cells to other hormones

Question 33

what are the causes of an underactive thyroid and what are the symptoms?

Answer 33

underproduction of thyroxine hormones. Symptoms include tiredness, weight gain and depression.

Question 34

what are the causes and symptoms of an overactive thyroid?

Answer 34

caused by an overproduction of thyroxine hormones. Symptoms can include exophthalmos (bulging eyes); weight loss (despite increased appetite) hyperactivity, lack of sleep, diarrhoea, polyuria, polydipsia.

Question 35

what is cretinism?

Answer 35

stunted physical and metal growth due to a congenital lack of thyroxine hormones. Characteristics can include a thick protruding tongue and drooling.

Question 36

where do the parathyroid glands develop from?

Answer 36

develop from the walls of the pharynx.

Question 37

where are the parathyroid glands located?

Answer 37

two pairs of glands (2 superior parathyroid glands and 2 inferior parathyroid glands) on the posterior aspect of the thyroid.

Question 38

which hormone does the parathyroid gland produce?

Answer 38

parathyroid hormone which stimulates osteoclasts to break down the bone matrix and increase blood calcium levels.

Question 39

wha are the three layers of epithelial cells that make up the cortex of the adrenal glands?

Answer 39

from surface: zona glomerulosa, zona fasciculata, zona reticularis

Question 40

what are the two different regions of the arenal glands?

Answer 40

cortex and medulla

Question 41

what hormones does the adrenal cortex produce?

Answer 41

steroid hormones: aldosterone, cortisol and sex steroids - androgens

Question 42

what hormones do the adrenal medulla produce?

Answer 42

the CHROMAFFIN cells produce: epinephrine (adrenaline), norepinephrine (noradrenaline) and dopamine

Question 43

what is cushing’s syndrome and what is caused by?

Answer 43

caused by an increased production of cortisol. Symptoms can include: weight gain, fatty deposits i the face, thinning skin which bruises easily, muscle or bone weakness.

Question 44

what are the exocrine functions of the pancreas?

Answer 44

PANCREATIC ACINI produces pancreatic amylase etc

disorder - pancreatitis

Question 45

what are the endocrine functions of the pancreas?

Answer 45

ISLETS OF LANGERHANS: alpha cells produce glucagon
beta cells produce insulin
disorder - diabetes mellitus

Question 46

what is cortisol?

Answer 46

hormone produced in the adrenal cortex and controls BP, blood sugar, can help reduce inflammation and assist with memory function. Can also control salt/water balance. overproduction can cause cushion’s syndrome.