MNSR 40 - Endocrinology: Endocrine systems: hormones

Question 1

Endocrinology

Answer 1

The branch of biology dealing with the endocrine glands and their secretions, esp. in relation to their processes or functions.

Question 2

Features of endocrine glands

Answer 2

ductless
secrete hormones
secreted directly into bloodstream

Question 3

hormones

Answer 3

A substance secreted by cells in one part of the body that passes to another part where it is effective, in very small concentrations, in regulating the growth or activity of the cells

Question 4

what will stimulate the release of the hormone

Answer 4

the appropriate receptor of the hormone

Question 5

how do hormones function

Answer 5

as long term regulators of many activities, often involved in homeostasis

Question 6

where do the secreted hormones go to and how are they transported

Answer 6

Transferred to the site of action, or target organ

Usually complexed with (transported by) plasma proteins - usually hydrophobic

Question 7

how are neurohormones (hormones released by neurons) released

Answer 7

Pass down the axon to the nerve endings

Released into special capillary networks near the target organ

Question 8

tissue hormones

Answer 8

hormones, produced in various parts of the body which have a local effect on cells and tissues

Question 9

examples of tissue hormones

Answer 9

Kinins
Prostaglandins (inflammatory mediator)
Gastrin (Gastric acid secretion)
Secretin (Regulation of pH in duodenum)
Cholecystokinin (Digestion of fat & protein).

Question 10

types of functionality of hormones

Answer 10

endocrine signalling
paracrine signalling
autocrine signalling

Question 11

endocrine signalling hormones

Answer 11

hormones acts on target sells distant from site of synthesis

e.g. adrenocorticotrophic hormone

Question 12

paracrine hormones

Answer 12

Signalling molecules act on neighbouring cells e.g. serotonin

Question 13

Autocrine hormone

Answer 13

Local regulators

Signalling molecules act on same cells to amplify signals

Question 14

4 main chemical groups

Answer 14

peptide hormones
amino acid derived hormones
steroid hormones
fatty acid hormones - derived from from arachidonic acid

Question 15

4 ways hormones control activity of cells and tissue of target organs

Answer 15

Influencing the rate of synthesis of enzymes or other proteins.
Altering the rate of enzyme catalysis
Speeding up or slowing down metabolic pathways.
Altering the permeability of the cell membrane.

Question 16

2 types of hormones

Answer 16

Cell-surface signalling – hydrophilic

Intracellular signalling - hydrophobic

Question 17

mechanism of action of steroid and thyroid hormones

Answer 17

easily pass through membrane into nucleus

interact w/ receptor to activate or recess specific genes - synthesis of specific proteins

Question 18

mechanism of action of peptide hormones

Answer 18

water soluble - can’t directly pass through membrane
GPCR - G Protein Coupled Receptor
hormones bind to receptor leads to conformational change in receptor
G protein is activated - moves away from receptor to activate next signalling protein in pathway usually adenylyl cyclaseATP – > cyclic-AMP
Phosphorylation cascade w/ protein kinase

Question 19

hypothalamus function in endocrine systme

Answer 19

Links nervous system to endocrine system

Receives input from other areas of brain and alters release of hormones in response

Question 20

what type of hormone does hypothalamus release

Answer 20

neurohormones

Question 21

where are hormones produced in hypothalamus usually stored in

Answer 21

pituitary gland for regular secretion of hormones

Question 22

through what system are hormones secreted in hypothalamus

Answer 22

hypothalamic-hypophyseal portal system

Question 23

name 3 main components of the hypothalamic-hypophyseal portal system

Answer 23

superior hypophyseal artery
primary capillary plexus
secondary capillary plexus

Question 24

function pituitary gland

Answer 24

Controls the other endocrine glands

Question 25

what influences and regulates pituitary gland

Answer 25

Influenced by endocrine glands via a system of mostly negative feedbacks Partially regulated by hypothalamus

Question 26

2 lobes of pitiuitary gland

Answer 26

``` Posterior pituitary (neurohypophysis) is neural tissue anterior pituitary (adenohypophysis) is glandular tissue ```

Question 27

how is pituitary gland attached

Answer 27

Attached by a short connection called the infundibular stalk (pituitary stalk) to the hypothalamus

Question 28

what is the posterior and anterior part of the pituitary gland derived from?

Answer 28

One part is derived from a downgrowth of the hypothalamus, the infundibulum, The other from Rathke’s pouch

Question 29

rathke's pouch

Answer 29

Depression of the roof of the developing mouth Breaks away from the pharynx Forms anterior pituitary

Question 30

hypothalamus extends to form

Answer 30

Infundibulum | Posterior pituitary

Question 31

what is posterior of pituitary gland composed of

Answer 31

Composed of two parts: pars nervosa and the median eminence

Question 32

where is anterior pituitary developed from

Answer 32

developed from an inpushing of the mouth ectoderm called Rathke's pouch.

Question 33

how many major hormones are secreted from anterior pituitary gland and how many of them are trophic

Answer 33

Seven major hormones are secreted by the anterior pituitary, four of which are trophic hormones

Question 34

trophic hormones

Answer 34

are hormones which have another endocrine gland as the target organ

Question 35

identify trend in hormones secreted by anterior pituitary gland

Answer 35

hormones appear to have both releasing and inhibitory factors The releasing function is dominant Prolactin is an exception; inhibited by dopamine

Question 36

name the 7 hormones released from the anterior pituitary gland

Answer 36

``` Growth Hormone Prolactin Follicle-stimulating Hormone Luteinizing Hormone Thyroid-stimulating Hormone Adrenocorticotrophic hormone Endorphins ```

Question 37

list the hormones released from hypothalamus

Answer 37

``` Growth hormone releasing hormone Prolactin releasing hormone ADH Oxytocin Gonadotrophin-releasing hormone Thyrotrophin-releasing hormone Corticotrophin-releasing hormone ```

Question 38

Hypothalamus-pituitary axis

Answer 38

The control and secretion of these hormones is under the direction of the hypothalamus which releases special neurohormones

Question 39

hormones secreted in posterior pituitary gland

Answer 39

oxytocin | ADH - vasopressin

Question 40

where is the pars intermedia and what hormone does it release

Answer 40

Boundary between the anterior and posterior lobes of the pituitary Melanocyte-stimulating hormone (MSH) An increase in MSH will cause a darkening in humans

Question 41

cushing's syndrome

Answer 41

high levels of adrenocoroticotropic hormone production - high MSH levels - > abnormal darkening