Principles Of Human Physiology Chapter 4

Front 1

What are the four main categories of chemical messengers?

Back 1

1)Paracrines
2)Neurotransmitters
3)Autocrines
4)Hormones

Front 2

Paracrines usually include...?

Back 2

growth factors, cytokines, and clotting factors

Front 3

What are cytokines?

Back 3

peptides released from immune cells that function in the body's defense against infections

Front 4

Histamine, a paracrine messenger, is secreted by what?

Back 4

mast cells

Front 5

Neurohormones are secreted by...?

Back 5

neurosecretory cells

Front 6

what are the five major classes of chemical messengers?

Back 6

1)amino acids
2)amines
3)peptides/proteins
4)steroids
5)eicosanoids

Front 7

What are the characteristics of the amine messengers?

Back 7

include a group called catecholamines (derived from tyrosine and includes dopamine, norepinephrine, and epinephrine). most amines are lipophobic and do not cross the membrane.

Front 8

What are the characteristics of the amino acid messengers?

Back 8

There are four that are classified as CMs because they funtion as neurotransmitters. They are glutamate, aspartate, glycine, and GABA. Amino acids are lipophobic and do not cross the membrane.

Front 9

What are the characteristics of peptide/protein messengers?

Back 9

more than 50=protein
less than 50=peptides
They are lipophobic and do not cross the membrane

Front 10

What are the characteristics of steroid messengers?

Back 10

-derived from cholesterol
-are lipophillic and cross the membrane

Front 11

Amines come from what neurotransmitter and by what process?

Back 11

Dopamine (tyrosine beta hydroxylase and dopa decarboxylase)

Norepinephrine(dopamine beta hydroxylase)

Epinephrine(PMNT)

Front 12

Eicosanoid synthesis requires what enzyme in its first step?

Back 12

phospholipase A2

Front 13

The cyclooxygenase pathway leads to what products?

Back 13

prostaglandins(inflammatory response), prostacyclins, or thromboxanes (blood clotting)

Front 14

The lipoxygenase pathway leads to what product?

Back 14

leukotrienes(inflammatory response)

Front 15

Most catcholamines that function as hormones are transported in what way?

Back 15

most are hydrophillic and so they are carried in the bloodstream in dissolved form.

Front 16

What is albumin?

Back 16

A carrier protein that can carry many different hormones

Front 17

What is a fast channel?

Back 17

A ligand-gated channel where the receptor and channel are the same protein. The binding of a messenger causes the channel to open, increasing the permeability of the membrane.

Front 18

What is an enzyme-linked receptor?

Back 18

transmembrane proteins with the receptor side facing the interstitial fluid and the enzyme side facing the the cytosol. most are tyrosine-kinases

Front 19

What is a G-protein?

Back 19

in its inactive state, it binds a GDP. when activated by a messenger, it releases the GDP and binds a GTP, moves to its effector, then hydrolyzes the GDP to return to its inactive state.

Front 20

What is a slow ligand-gated ion channel?

Back 20

one that is regulated by G proteins. G-proteins also catalyze the production of amplifier enzymes.

Front 21

cAMP Second Messenger System

Back 21

1. messenger activates G protein
2. effector: adenylate cyclase
3. adenylate cyclase catalyzes the conversion of ATP to cAMP
4. cAMP activates protein kinase A
5. phosphorylation, altered protein activity, response

Front 22

What is the function of the posterior pituitary?

Back 22

secretes two peptide hormones: anitdiuretic hormone (ADH, also called vasopressin) and oxytocin

Front 23

Prolactin Releasing Hormone (PRH)

Back 23

secreted by the hypothalamus. stimulates the anterior pituitary to release prolactin, which stimulates mammary gland development and milk secretion in females

Front 24

Prolactin Inhibiting Hormone (PIH), or dopamine

Back 24

secreted by the hypothalamus. inhibits the release of prolactin

Front 25

Thyrotropin releasing hormone (TRH)

Back 25

released by the hypothalamus. stimulates the release of thyroid stimulating hormone (TSH) from the anterior pituitary. TSH then stimulates the secretion of TH by the thyroid.

Front 26

Corticotropin releasing hormone (CRH)

Back 26

secreted by the hypothalamus. stimulates the release of adrenocorticotropic hormone (ACTH) by the anterior pituitary. ACTH then stimulates secretion of other hormones by the adrenal cortex.

Front 27

Growth Hormone Releasing Hormone (GHRH)

Back 27

secreted by the hypothalamus. stimulates the secretion of growth hormone (GH) by the anterior pituitary. GH regulates growth and energy metabolism but also functions as a tropic hormone by stimulating the secretion of IGFs from the liver.

Front 28

Growth Hormone Inhibiting Hormone (GHIH) or somatostatin

Back 28

secreted by the hypothalamus. inhibits the secretion of growth hormone by the anterior pituitary.

Front 29

Gonadotropin Releasing Hormone (GnRH)

Back 29

secreted by hypothalamus. stimulates the release of both FSH and LH by the AP. LH stimulates ovulation in females and stimulates the secretion of sex hormones by the gonads.

Front 30

What is the function of the pineal gland?

Back 30

secretes melatonin and controls circadian rhythms. melatonin enhances the immune system and exerts a suppressive effect on the reproductive system.

Front 31

What does the thyroid secrete?

Back 31

T3, T4, and Calcitonin

Front 32

Adrenocorticoids include 3 types of hormones: ?

Back 32

Mineralocorticoids
Glucocorticoids
Sex Hormones

Front 33

What do mineralcorticoids do?

Back 33

1)Mineralocorticoids (primarily aldosterone). Excreted by the zona glomerulosa. regulate sodium reabsorption and K secretion by the kidneys

Front 34

What do Glucocorticoids do?

Back 34

2)Glucocorticoids (primarily cortisol). secreted by the zona fasciculata and zona reticularis. regulate the body's response to stress; protein, carbohydrate, and lipid metabolism in a variety of tissues, and blood glucose levels.

Front 35

What do sex hormones in the adrenal gland do?

Back 35

Sex hormones (primarily androgens) are secreted by cells in the zona reticularis (and by the gonads). In females adrenal androgens stimulate the sex drive.

Front 36

What are the exocrine functions of the pancreas?

Back 36

includes acinar and duct cells that secrete enzymes and fluid into the GI tract.

Front 37

What are the endocrine functions of the pancreas?

Back 37

has cell clusters called Islets of Langerhans that are scattered throughout the pancreas in spaces between the ducts. Has alpha (glucagon) cells and beta (insulin) cells.

Front 38

What is the function of the adrenal medulla?

Back 38

it contains chromaffin cells and secretes catecholamines(about 80% is epinephrine (adrenaline), 20% is norepinephrine, and less than 1% is dopamine)

Front 39

What are the heart's functions as a secondary endocrine organ?

Back 39

it secretes atrial natriuretic peptide (ANP) which regulates sodium reabsorption by the kidneys

Front 40

What are the kidney's function as a secondary endocrine organ?

Back 40

it secretes erythropoietin, which stimulates the production of red blood cells by bone marrow

Front 41

What are the secondary endocrine functions of the skin with the help of the kidneys?

Back 41

the production of 1, 25-dihydroxy vitamin D3, which regulates blood calcium levels