Endocrine

Question 1

Endocrine overview
Slide 2

Answer 1

The endocrine system works with the nervous system. It influences metabolic activities via hormones. Controlled mostly by negative feedback systems.

Question 2

Endocrine glands
Slide 4

Answer 2

Lack ducts
Produce hormones

Question 3

Neuroendocrine organ
Slide 5

Answer 3

Hypothalamus

Question 4

Hormones
Slide 7

Answer 4

Long distance chemical signals; travel in blood or lymph

Question 5

Autocrines
Slide 7

Answer 5

Chemicals that exert effects on the same cells that secrete them

Question 6

Paracrines
Slide 7

Answer 6

Locally acting chemicals that affect cells other than those that secrete them

Question 7

Two main classes of hormones
Slide 7

Answer 7

Amino acid-based hormones
Steroids

Question 8

Possible third class of hormones
Slide 7

Answer 8

Eicosandoids

Question 9

Target cells
Slide 8

Answer 9

Tissues with receptors for a specific hormone

Question 10

How do water soluble hormones act?
Slide 9

Answer 10

Act on plasma membrane receptors
Act via G protein second messengers
Cannot enter cell

Question 11

How do lipid soluble hormones act?
Slide 9

Answer 11

Act on intracellular receptors that directly activate genes
Can enter cell

Question 12

Cyclic AMP second-messanger mechanism of water soluble hormones
Slide 10

Answer 12

G protein signaling mechanisms are like a molecular relay race

Question 13

Intracellular receptors and direct gene activation
Side 11

Answer 13

Lipid soluble steroid hormones and thyroid hormones can diffuse into target cells and bind w intracellular receptors
Helps initial DNA transcription to produce mRNA
mRNA translated to specific protein

Question 14

Hormone release
Slide 13

Answer 14

Controlled by negative feedback systems ^ hormone effects on target organs can inhibit further hormone release
Hormone release can be triggered by
-endocrine gland stimuli
-nervous system modulation

Question 15

Humoral stimuli
Slide 14

Answer 15

Changing blood levels of ions and nutrients directly stimulate secretion of hormones

Question 16

Humoral stimuli example

Answer 16

Declining Ca+ stimulates parathyroid glands to secrete PTH> PTH causes Ca+. concentrations to rise and stimulus is removed

Question 17

Neural stimuli

Answer 17

Nerve fibers stimulate hormone release

Question 18

Neural stimuli example
Slide 15

Answer 18

Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines

Question 19

Hormonal stimuli
Slide 16

Answer 19

Hormones stimulate other endocrine organs to release their hormones

Question 20

Target cell specificity

Answer 20

Target cell activation depends on 3 factors
-blood levels of hormone
- relative # of receptors on/in target cell
-affinity (strength) of binding receptor and hormone

Question 21

Up regulation

Answer 21

Target cells form more receptors in response to low hormone levels

Question 22

Down regulation

Answer 22

Target cells lose receptors in response to high hormone levels

Question 23

Half life

Answer 23

Time required for the level of hormone in blood level to decrease by half

Question 24

Comparison between lipid and water soluble hormones table
Slide 20

Question 25

Hypothalamus

Answer 25

Connected to pituitary glad (hypophysis) via stalk called infundibulum

Question 26

Two major lobes of hypothalamus

Answer 26

Posterior pituitary and anterior pituitary

Question 27

Posterior pituitary

Answer 27

Composed of neural tissue that secretes neurohormones Posterior lobe + infundibulum make up neurohypophysis

Question 28

Neurohypophysis

Answer 28

Posterior lobe+ infundibulum

Question 29

Anterior pituitary (adenohypophysis)

Answer 29

Consists of glandular tissue

Question 30

Posterior lobe maintains connection to hypothalamus via

Answer 30

Hypothalamic-hypophyseal tract

Question 31

Hypothalamic-hypophyseal tract arises from neurons in

Answer 31

Paraventricular and supraoptic nuclei in hypothalamus Runs through infundibulum Secretes two neurohormones -oxytocin and ADH

Question 32

ADH

Answer 32

Causes reabsorption of water and vasoconstriction

Question 33

Oxytocin

Answer 33

Feeling of affection Contracture of uterine musculature

Question 34

ADH

Answer 34

Can cause vasoconstriction Targets kidneys Hypothalamus contains osmoreceptors that monitor solute concentrations

Question 35

Clinical imbalance Diabetes insipidus Syndrome of inappropriate ADH secretion

Answer 35

ADH deficiency due to damage to the hypothalamus or posterior pituitary Retention of fluid, headache, disorientation

Question 36

Anterior pituitary hormones All activate target cells via cAMP besides GH

Answer 36

GH TSH ACTH FSH LH PRL

Question 37

Growth hormone

Answer 37

Produced by somatotropic cells Direct actions on metabolism

Question 38

Regulation of GH

Answer 38

GHRH- stimulates GH release GHIH- inhibits release

Question 39

Clinical imbalance

Answer 39

Hypersecretion of GH- gigantism + acromegaly Hyposecretion- pituitary dwarfism (children) adult no probs

Question 40

Thyroid stimulating hormone

Answer 40

Also called Thyrotropin produced by thyrotropic cells release triggered by throtropin-releasing hormone from hypothalamus

Question 41

Adrenocorticotropic hormone ACTH

Answer 41

Also called corticotropin secreted by corticotropin cells release triggered by corticotropin-releasing hormone CRH