module 8

Question 1

what does the endocrine system do

Answer 1

The endocrine system manifests slows (mintues to hours) but lasts a long time.
it consists of a number of ductless glands that produce and secrete hormones directly into the blood.
Only interacts with target cells that have the appropriate receptors
Binding of hormones to their receipts alters the activity of target cells they act as chemical messengers.

Question 2

what does binding of a hormone to a receptor produces one or more of the following effects

Answer 2

Alters the permeability of the plasma membrane e. Permeability to ions, nutrients and water to help maintain electrolyte, fluid, and nutrient balance of the blood.
Stimulates protein Synthese eg syntheses o protein hormones to be secreted.
Activates or deactivates enzymes within the cell eg ATP production
Increases or decrease the secretary activity of the cell eg. Stimulates hormone secrete
Stimulates cell divas and therefore regulates reproduction, growth and development

Question 3

what are steroid hormones

Answer 3

synthesised from cholesterol, are lipid soluble and include sex hormones made by the ovaries and testes eg oestrogen and testosterone.
AND hormones produced by the adrenal cortex eg. Cortisol and aldosterone.
steroid(thyroid) hormones are lipid solubile= easily diffuse across the plasma membrane of a target cell to bind to receptors in the cytoplasm.

Question 4

what the steps of steroid hormones transport

Answer 4

1. Steroid hormone diffuses through plasma membrane and binds to an intracellualar receptor.
2. Receptor hormone complex enter the nucleus
3. The receptor hormone complex binds to a specific DNA region (sequence)
4. Binding initiates transcription of the gene to mRNA
5. The mRNA directs proteins synths
6. The new protein alter the cells activity to cause the repose typical of the hormone.

Question 5

whats amino acid based hormones

Answer 5

most are amino acid based
Size varies from simple amino acids to peptide to proteins
They are usually lipid insoluble (or water soluble)
They cannot diffuse cross the plasma membrane of target cell
Receptors located on the surface of the plasma membrane.

Question 6

whats the steps of an amino acids

Answer 6

1. Binds to receptor on plasma membrane surface
2. Receptors activates G protein
3. G protein activates an anzyme
4. Enzyme catalyses a reaction to produce a 2n messenger
5. Target response produced

Question 7

whats the amino acid thats different

Answer 7

thyroid hormones are lipid soluble but their mechanism of action is similar to lipid soluble hormones

Question 8

whats the three types of stimuli that control the production and secretion from endocrine glands

Answer 8

humoral stimulus
neural stimulus
hormonal stimuls

Question 9

whats a humoral stimulus

Answer 9

hormones are secreted in response to changing levels of certain ions or nutrients in the blood.

Question 10

whats a neural stimulus

Answer 10

hormone secretion is controlled by the nervous system.

Question 11

whats a hormonal stimulus

Answer 11

hormones are secreted in response to hormones produced by otherendocrine glands (i.e. one hormone stimulates the secretion of another).

Question 12

whats considerations part of the endocrine system

Answer 12

any cell or tissue the produces or secretes hormones

Question 13

whats the major endocrine glands

Answer 13

hypothalmus
pituirtay gland
pineal gland
thyroid gland
parathyroid gland
thymus
adrenal gland
pancreas
gonads

Question 14

whats the hypothalamus

Answer 14

produces a number of different hormones, including those that control theendocrine function of the pituitary gland

Question 15

whats the pituitary gland

Answer 15

produces and secretes hormones that regulate the endocrine activities ofvarious organs

Question 16

whats the pineal gland

Answer 16

produces and secretes melatonin which regulates circadian rhythm

Question 17

whats the thyroid gland

Answer 17

produce and secretes thyroid hormone and calcitonin

Question 18

whats the parathyroid gland

Answer 18

produces and secretes parathyroid hormone

Thymus - produces and secretes hormones that develop and maintain immune defences

Question 19

whats the adrenal gland

Answer 19

produces and secretes adrenalin and noradrenalin

Question 20

whats the pancreas

Answer 20

produces and secretesinsulin and glucagon

Question 21

whats the gonads

Answer 21

(ovaries in females, testis in males) produce the sex hormones responsible for the maturation of reproductive organs and the development of secondary sex characteristics

Question 22

whats the posterior pituritary

Answer 22

not technically an endocrine gland
Does not prouduce its own hormones but secretes those produced by the hypothalamus.
Connected to hypothalamus by a bundle of neuron axons called hypothalamic-hypophyseal tract.
The cell bodies of theses neurons synthesis the hormones oxytocin and ADH, and their axons transport these hormones to the posterior piturity.
When the hypothalamic neurons are stimulated they release the stored hormones into a capillary bed within the posterior pituritary fr distribution throughout the body.

Question 23

whats the anterior pituitary

Answer 23

comprised of endocrine cells that produce and secrete a number of different hormones
Under the control of regulating hormones produced by the hypothalamus
Releasing hormones stimuluate the anterior pituitary to secrete particular hormone
Inhibiting hormones prevent the anterior pituitary from secreting a particular hormones
AWhatlso connected to hypothamus but is a vascular connection called hypophyseal portal system
The vascular connection links blood supple of the hypothalamus with that of the anterior pituitary and transports the regulating hormones produced by the hypothalamic neurons to the anterior pituitary gland

Question 24

whats the site of production
stimulus secretion
and main action of ADH

Answer 24

Site of productions: produced by hypothalamus and released by posterior pituritary
Stimulus for secretion: in response to an increase in blood sodium concentration or decrease in blood volume and blood pressure
Main action: targets kidneys and increases the amount of water reabsorbed from the urine into the blood. THs decreases sodium concentration to homeostatic levels, decreases urine output and conserves body water to regulate blood volume and pressure.
casuses vasocontrition of arterioles at high concentrations

Question 25

what does hypo secretion of ADH result in

Answer 25

diabetes insipidus. Can be causes by a blow to the head that damages the hypothalamus or posterior pituitary and symptoms include extreme thirst, excessive urination .

Question 26

whats the site of production stimulus of secretion main action of oxycytocin

Answer 26

Site of production and secretion: Oxytocin is produced by the hypothalamus and released from the posterior pituitary. Stimulus for secretion: Oxytocin is secreted in response to the stretching of the cervix during labour, and the suckling action of the infant after birth. Main actions: Oxytocin stimulates uterine contractions during childbirth and the ejection of milk from the mammary glands during breastfeeding.

Question 27

whats the site of production and secretion stimulus fro secretion main action of prolactin

Answer 27

Site of production and secretion:  PRL is produced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of PRL is controlled by the hypothalamic regulating hormone, prolactin- inhibiting hormone (PIH). Low levels of PIH lead to an increase in PRL release. Main action: PRL stimulates milk production (lactation).

Question 28

whats the site of production stimulus for secretion main action of Follicle stimulating hormone (FSH)

Answer 28

roduced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of FSH is controlled by the hypothalamic regulating hormone, gonadotropin-releasing hormone (GnRH). Main actions: ovaries= stimulates sectreion of oestrogen and follicle (oocyte) development. testes= stimulates sperm production

Question 29

whats the site of production stimulus for secretion main action of Luteinising hormone (LH)

Answer 29

produced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of LH is controlled by the hypothalamic regulating hormone, gonadotropin-releasing hormone (GnRH). Main actions: ovaries= stimulates secretion of oestrogen and progesterone, stimulates ovulation testes= stimulates secretion of testosterone

Question 30

whats the site of production stimulus for secretion main action of insulin

Answer 30

Site of production and secretion: Insulin is produced and secreted by the β cells in the pancreas. Stimulus for secretion: Insulin is secreted when blood glucose levels increase above the normal range. Main actions: Insulin decreases blood glucose to normal levels by stimulating target cells (i.e. most body cells) to take up glucose from the blood. It also stimulates these cells to utilise the glucose for ATP (energy) production (this process is known as glycolysis), and stimulates the liver and skeletal muscles to convert glucose to glycogen for storage (this process is known as glycogenesis).

Question 31

type 1 diabetes is caused by

Answer 31

inadequate insulin production due to the destruction of pancreatic β cells by the body’s own immune system (autoimmune disease)

Question 32

type 2 diabetes occurs when

Answer 32

cells do not respond to the insulin being produced and appear to be “insulin resistant”

Question 33

whats the site of production and secretion stimulus for secretion main action of glucagon

Answer 33

Site of production and secretion: Glucagon is produced and secreted by the a cells in the pancreas  Stimulus for secretion: Glucagon is secreted when blood glucose levels decrease below the normal range. Main actions: Glucagon increases blood glucose to normal levels. It primarily targets the liver where it stimulates:   the breakdown of stored glycogen to glucose (this process is known as glycogenolysis) the production of glucose from amino acids and glycerol (this process known as gluconeogenesis) the release glucose into the bloodstream

Question 34

whats the site of production and secretion stimulus for secretion main action for growth hormone (GH)

Answer 34

Site of production and secretion: GH is produced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of GH is controlled by two hormones produced by the hypothalamus: Growth hormone-releasing hormone (GH-RH) - stimulates the secretion of GH Growth hormone-inhibiting hormone (Somatostatin) - inhibits the secretion of GH Main action: As is name suggests, GH mediates the growth of a body tissues, especially skeletal muscle and bone. Growth hormone stimulates the liver, muscle and bone to produce a hormone called insulin like growth factor (IGF), which stimulates the actions required for growth, i.e. cell division, protein synthesis and the uptake of glucose from the blood to fuel the process of growth (hence the name “insulin-like”). 

Question 35

what does hypo secretion or hyper secretion of GH lead to

Answer 35

The hypo-secretion of GH leads to dwarfisms and hyper-secretion leads to gigantism (in children) acromegaly (in adults).

Question 36

whats the site of production and secretion stimulis for secretion main action for adrenocorticotropic hormone (ATCH)

Answer 36

Site of production and secretion: ACTH is produced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of ACTH is controlled by the hypothalamic regulating hormone, corticotropin-releasing hormone (CRH). Main action: ACTH stimulates the adrenal cortex to secrete the hormone cortisol.

Question 37

whats the site of production and secretin stimulus for secretion main action for cortisol

Answer 37

Site of production and secretion: Cortisol is produced and secreted by the adrenal cortex. Stimulus for secretion: The secretion of cortisol is controlled by the anterior pituitary hormone, ACTH. Main actions: Cortisol is a glucocorticoid as it helps maintain blood glucose levels by stimulating the liver to produce glucose from amino acids and glycerol (a process known as gluconeogenesis) when blood glucose levels are low. Cortisol also helps the body resist stress by providing the energy (glucose) required for a fight-or-flight response, and acts as a potent anti-inflammatory agent by inhibiting activities of the immune system. 

Question 38

whats the HPA axis

Answer 38

Hypothalamus Pituitary gland Adrenal gland Produces cortisol

Question 39

whats the site of production and secretion stimulus for secretion main action of aldosterone

Answer 39

Site of production and secretion: Aldosterone is produced and secreted by the adrenal cortex. Stimulus for secretion: Aldosterone is secreted in response to an increase in blood potassium (K+) levels or the hormone angiotensin II which is produced by liver in response to a decrease in blood Na+ concentration and a decrease in blood volume/blood pressure. Main actions: Aldosterone is a mineralocorticoid as it regulates the blood concentration of certain minerals, in particular K+ and Na+. It also helps maintain blood volume and blood pressure. Aldosterone primarily targets the kidneys where it stimulates the: secretion of K+ from the blood into the urine, lowering blood K+ levels to homeostatic concentrations reabsorption of Na+ from the urine into the blood, increasing blood Na+ levels to homeostatic concentrations

Question 40

whats the site of production and secreiton stimulus for secretion main action for adrenaline and noradrenaline

Answer 40

Site of production and secretion: Adrenalin and noradrenalin are produced and secreted by the adrenal medulla. Adrenalin accounts for approximately 80% of the hormones secreted from the adrenal medulla, the rest being noradrenalin. Stimulus for secretion: The secretion of adrenalin and noradrenalin is controlled by the sympathetic division of the autonomic nervous system. Main actions: Adrenal and noradrenalin bind to adrenergic receptors (a and β) on cells in various organs including the heart, lungs and blood vessels, and they enhance and prolong the fight-or-flight response (i.e. actions of the sympathetic division of the ANS). Adrenalin and noradrenalin therefore: increase heart rate and force of contraction dilate bronchioles to increase respiratory airflow dilate blood vessels supplying skeletal muscles and heart constrict blood vessels supplying the skin, digestive organs and kidneys dilate pupils decrease digestive and urinary functions

Question 41

whats the site of production and secretion stimulus for secretion main action of Erythropoietin (EPO) day

Answer 41

Site of production and secretion: EPO is produced and secreted by the kidneys. Stimulus for secretion: EPO is secreted in response to a decline in the number of red blood cells circulating in the blood. Main action: EPO signals the bone marrow to increase the rate of red blood cell production (erythropoiesis). 

Question 42

what happens when too little EPO is secreted from the kidneys

Answer 42

person may have anaemia

Question 43

whats the site of production and secretion stimulus for secretion main action for thyroid stimulating hormone (TSH

Answer 43

Site of production and secretion: TSH is produced and secreted by the anterior pituitary. Stimulus for secretion: The secretion of TSH is controlled by the hypothalamic regulating hormone, thyrotropin-releasing hormone (TRH). Main action: TSH stimulates the thyroid gland to secrete the hormones T3 (triiodothyronine) and T4 (thyroxine) - collectively called thyroid hormone (TH). 

Question 44

whats the site of production and secretion stimulus for secretion main actions for the thyroid hormone (TH)

Answer 44

Site of production and secretion: T3 and T4 (TH) are produced and secreted by specialised follicular cells of the thyroid gland. Stimulus for secretion: The secretion of TH is controlled by the anterior pituitary hormone, TSH. Main actions: TH affects virtually every cell in the body and acts to: increase basal metabolic rate (BMR) - i.e. the amount of energy required by body cells to carry out all metabolic reaction at rest increases body temperature - an increase in metabolism = an increase in heat production = an increase in body temperature regulate tissue growth and development -  in particular the nervous and musculoskeletal systems

Question 45

what does hyosecretion of TH

Answer 45

results in a low BMR, decreased body temperature, cold intolerance and weight gain

Question 46

whats does hypersecreiton of TH

Answer 46

results in an above normal BMR, increased body temperature and weight loss

Question 47

whats the site of production and secretion stimulus for secretion main actions of calcitionin

Answer 47

Site of production and secretion: Calcitonin is produced and secreted by the parafollicular cells of the thyroid gland. Stimulus for secretion: Calcitonin is secreted when blood Ca2+ levels increase above the normal range. Main action: Calcitonin stimulates the uptake of Ca2+ from the blood into bone. This decreases blood Ca2+ concentration to normal levels.

Question 48

whats the site of production and secretion stimulus for secretion main actions of parathyroid hormone (PTH)

Answer 48

Site of production and secretion: PTH is produced and secreted by the parathyroid glands.  These glands are located in the posterior aspect of the thyroid gland. There are usually four glands, but the number does vary – as many as eight have been found in some individuals.  Describe how hormonal secretion is regulated by positive feedback using oxytocin as an example and by negative feedback using thyroid hormone as an example. Stimulus for secretion: PTH is secreted when blood Ca2+ levels decrease below the normal range. Main actions: PTH increases blood Ca2+concentration to normal levels by: stimulating osteoclasts (a type of bone cell) to digest or breakdown bone and release Ca2+ into the blood. increasing the reabsorption of Ca2+ at the kidneys (so that it remains in the body rather than being excreted in urine) activating vitamin D (a.k.a. calcitriol) to promote the absorption of Ca2+ from the gastrointestinal tract